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Profilers en meetboeien

2026-11-11T13:21:42Z

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Profilers blijven in tegenstelling tot meetboeien niet aan het oppervlak maar maken een profieldoorsnede van de waterfase.
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=<span style="color:#00787A">Meetboeien</span>=
Alhoewel meetboeien bestaan in tal van types, kunnen ze opgesplitst worden in twee groepen: vrij drijvende (Figuur 1) en verankerde boeien (Figuur 2)<ref name="een">http://www.jcommops.org/dbcp/platforms/types.html</ref>. Beiden zijn uitgerust met allerlei sensoren en meettoestellen die gegevens verzamelen en waarbij deze automatisch via realtime satelliet communicatie worden doorgestuurd. Metingen worden geleverd van onder meer water- en luchttemperatuur, luchtvochtigheid en –druk, wind, golfhoogte en saliniteit. Samen met complementaire methodes, zoals [[teledetectie|remote sensing]] en [[Schepen en instrumentarium|schepen met instrumentarium]], kunnen ze meehelpen om een accuraat beeld over de toestand van het oceaanoppervlak te verkrijgen. <P>
Meetboeien worden op grote schaal ingezet vanwege hun hoge efficiëntie voor het bekomen van meteorologische en oceanografische data. Als in voldoende aantal uitgezet, bestrijken ze een groot oppervlak. Ze kunnen ook gebruikt worden in afgelegen gebieden. Zo zijn er zogenaamde ijsboeien met aangepaste sensoren en batterijen, bestand tegen extreem lage temperaturen. Verder hebben meetboeien een uitermate accuraat satelliet positioneringssysteem zodat ze vlot teruggevonden kunnen worden<ref name="een"/>. Een groot aantal wordt onderhouden door het DBCP ([http://www.jcommops.org/dbcp/ Data Buoy Cooperation Panel]), dat onder meer instaat voor de progressie van het netwerk en de standaardisatie van de boeien. Het DBCP bestaat uit verscheidene werkgroepen, die focussen op vrij drijvende of verankerde boeien.

==<span style="color:#00787A">''Drijvende boeien'' </span>==
[[Image:Drifting_buoy.png|thumb|right|250px|Figuur 1: Drijvende boei met sleepanker<ref name="een"/>.]]
Vrij drijvende boeien (drifting buoys) zijn niet vastgeankerd aan de bodem maar worden nabij hun oorspronkelijke plaats gehouden door een zee- of sleepanker. Een zeeanker is een soort kunststoffen parachute die met nylondraad onderwater aan de boei vastgemaakt wordt en zo de weerstand vergroot, waardoor de positie min of meer behouden blijft. Een sleepanker is kleiner en heeft een meer conische vorm, maar functioneert analoog. Als na zekere tijd de boeien te ver zijn afgedreven, worden ze met een schip herplaatst, net zoals gebeurt met Argo floats. Samengevat zijn het gebruiksvriendelijke, relatief goedkope en betrouwbare observatie instrumenten<ref name="een"/>.

===Overkoepeling===
Ongeveer 1250 van deze boeien werden ondergebracht in het GDP ([http://www.aoml.noaa.gov/phod/dac/index.php Global Drifter Program]), onder leiding van [http://www.jcomm.info/ JCOMM] en het [http://www.aoml.noaa.gov/ AOML], dat instaat voor het behoud van dit netwerk (met een 5x5 graden precisie) en het voorzien van een data verwerkend systeem dat wetenschappelijk gebruik ondersteunt<ref name="twee">http://unesdoc.unesco.org/images/0018/001878/187825E.pdf </ref>. Het GDP is één van de werkgroepen binnen het DBCP.

===Toepassingen===
Deze relatief eenvoudige boeien dragen apparatuur voor het meten van de [[Temperatuur, dichtheid/saliniteit en stromingen|temperatuur, saliniteit]] en [[Weer en klimaat|meteorologische variabelen]] (wind, atmosferische druk). De gegevens worden via satelliet in real-time doorgestuurd naar de dataverwerkingscentra. Deze data worden wereldwijd onder meer ingeschakeld als ondersteuning voor meteorologische diensten. Tevens zijn in-situ metingen van de oppervlaktetemperatuur nodig voor het kalibreren van temperaturen bepaald door satellieten, zodat satellietdata nauwkeuriger wordt<ref name="twee"/>.

==<span style="color:#00787A">''Verankerde boeien'' </span>==
[[Image:Mooring_buoy.png|thumb|right|250px|Figuur 2: vastgeankerde boei met zonnepanelen<ref name="een"/>.]]
Verankerde meetboeien worden met de hulp van een schip verankerd in de zeebodem met een kabel. Ook het onderhoud geschiedt vanaf het onderzoeksschip. Als ze losslaan kan snel worden ingegrepen om verlies aan materiaal, data (soms wordt zoveel data verzameld dat niet alles doorgestuurd geraakt) en mogelijk gevaar voor andere schepen te voorkomen. Hiertoe is een extra mechanisme ingebouwd dat alarmeert wanneer de boei een bepaald gebied verlaat.

===Overkoepeling===
Het GTMBA ([http://www.pmel.noaa.gov/tao/global/global.html Global Tropical Moored Buoy Array]) is een multinationaal en wereldwijd programma van verankerde boeien, zowel voor klimaatonderzoek als voor seizoenale voorspellingen. Dit initiatief wordt regionaal ingevuld, bijvoorbeeld onder de naam [http://www.pmel.noaa.gov/tao/ TAO/TRITON] in de Stille oceaan, [http://www.pmel.noaa.gov/pirata/ PIRATA] in de Atlantische oceaan en [http://www.pmel.noaa.gov/tao/rama/ RAMA] in de in de Indische oceaan<ref name="een"/>. Dit zijn eveneens werkgroepen van het DBCP.

===Toepassing===
Ze voorzien een constante stroom aan atmosferische (luchttemperatuur, windsnelheid en –richting) en oceanische (watertemperatuur, golfhoogte, -periode en -voortplantingsrichting) data afgelegen gebieden<ref name="drie">http://www.ndbc.noaa.gov/mooredbuoy.shtml</ref>. Niet alleen het oppervlak wordt gemonitord, ook tot dieptes van 500m kunnen gegevens verzameld worden<ref name="een"/>. Sensoren kunnen aan het ankertouw bevestigd worden en gegevens kunnen via de kabel naar de boei verzonden worden. Omdat de boeien doorgaans ook voorzien zijn van zonnepanelen, kunnen ze meer metingen uitvoeren en data transfereren gedurende langere periodes dan wat mogelijk is met Argo floats en drijvende boeien<ref name="twee"/>.
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=<span style="color:#00787A">Profilers</span>=
==<span style="color:#00787A">''Argo floats'' </span>==
[[Image:Argo_opbouw.gif|thumb|right|150px|Figuur 5: Opbouw van de floats<ref name="twee"/>.]]
Argo floats (soms ook boeien of profilers genoemd) zijn autonome observatiesystemen die verticale profielen nemen tot een diepte van 2km. Argo is de naam van het schip van Jason dat volgens de Griekse mythologie een queeste ondernam naar het gulden vlies. De naam Argo verwijst dus naar de complementariteit met de Jason [[Teledetectie#Zeespiegelhoogte en oppervlaktetopografie|altimetrie]] satelliet die de hoogte van het zeeoppervlak meet. Samengevoegde data geven informatie over de oceaanstromingen<ref name="zes">http://www.argo.ucsd.edu/Argo_new_brochure.pdf</ref>. <P>
Argo floats zijn gemakkelijk te plaatsen en relatief goedkoop. Deze kleine cilindrische meettoestellen zijn dan ook efficiënt bij het systematisch verzamelen van gegevens in het ijsvrije deel van de oceaan. Watermassa’s onder het ijs kunnen onderzocht worden via het [[Tagging van zeedieren|taggen van zeedieren]] en met [[Duiktuigen|duiktuigen]].

===Overkoepeling===
Meer dan 3500 floats (Figuur 3) zijn vandaag operationeel in het internationaal [http://www.argo.net/ Argo programma], dat werd opgericht in 1998 en waaraan ondertussen (2012) 31 landen deelnemen. Elk land is verantwoordelijk voor de aankoop en plaatsing van de floats. Het geheel wordt gecoördineerd door het Argo Project Office. Het netwerk aan Argo floats laat toe elk jaar 100.000 profielen te nemen, 20 keer meer dan het aantal profielen genomen vanaf onderzoeksschepen en 4 keer zoveel als het aantal [[Schepen en instrumentarium#XBT|XBTs]] genomen vanaf commerciële schepen. Met name afgelegen gebieden plukken hier de vruchten van. Bovendien zijn de verzamelde diepteprofielen veel minder onderhevig aan weersomstandigheden en/of lopende wetenschappelijke projecten<ref name="vier">http://www.argo.ucsd.edu</ref>.<P>
Sinds 2004 neemt Nederland deel aan het programma. Ze bekostigden de aankoop van 49 floats, waarvan er nu nog 38 in werking zijn<ref name="vijf">http://www.knmi.nl/~sterl/Argo/#profiler</ref>. De Europese Unie behoort ook tot de landenlijst.
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[[Image:Argo_map.jpg|thumb|centre|400px|Figuur 3: Kaart met aanduiding van de locatie van alle Argo floats operationeel op 8 Augustus 2012<ref name="twee"/>.]]

===Toepassingen===
Argo floats meten de druk, saliniteit en temperatuur. De laatste twee grootheden zeggen iets over de stroming. De bepaling van druk is nodig voor het berekenen van de diepte. Al deze gegevens zijn essentieel voor het opstellen van globale modellen voor onder meer watercirculatie en warmtetransfer. Die modellen laten toe om voorspellingen te doen van fenomenen zoals El Niño en moessontijden. Ook klimaatsopwarming kan bestudeerd worden met de bekomen data<ref name="twee"/>.

===Werking===
De floats worden te water gelaten vanop een schip, waarna ze hun tiendaagse cycli van metingen beginnen (Figuur 4). Argo floats kunnen hun drijfvermogen regelen door mechanisch hun volume te veranderen. Dit gebeurt door het in- of uitpompen van hydraulische olie in een externe blaas (Figuur 5). Eerst zinken de floats vanaf het oppervlak tot een diepte van 1km, waar ze “parkeren” voor ongeveer 9 dagen. Dit doen ze om scheepsschroeven en vissersnetten te vermijden. Vervolgens duiken ze naar 2 km diepte, van waaruit ze al stijgend beginnen meten. Na ongeveer 7 uur wordt het oppervlak weer bereikt en worden de geografische positie en gegevens doorgegeven via satelliet naar een data centrum. Dit duurt ongeveer een halve dag, en hierna begint de cyclus opnieuw. De doorgestuurde gegevens van al de floats wereldwijd worden samengebracht en indien mogelijk publiek beschikbaar gesteld binnen de 24 uur. Omdat de floats meegenomen worden door de stroming is het noodzakelijk deze regelmatig te herplaatsen<ref name="vijf"/><ref name="zes"/><ref name="twee"/>.
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[[Image:Argo_schema.jpg|thumb|centre|400px|Figuur 4: Tiendaagse cyclus afgelegd door de Argo float<ref name="twee"/>.]]

==<span style="color:#00787A">''Gliders'' </span>==
[[Duiktuigen#Gliders|Gliders]] kunnen zowel aanzien worden als duiktuigen als profilers.
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=<span style="color:#00787A">Bronnen</span>=
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[[Category:Oceaanobservatie]]

{{author
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|AuthorName=Elisabeth Van Beveren}}

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Traits:Marine species traits

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{{Box Note|boxtype=warning|Note text=This page is no longer updated. More recent information can be found at https://marinespecies.org/traits/aphia.php?p=attrdefinitions|https://marinespecies.org/traits/aphia.php?p=attrdefinitions }}
==About==
<br/>
The hierarchy of traits has been organised into a series of four "collections" to aid navigation and use. Use the search box to find the term or definition of interest.
{{#ask: [[Category:Mstcollections]]
| limit=500
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This wiki hosts the Marine Species Traits Vocabulary. All terms and their definitions have yet to be stabilized, and so should be considered 'under development'.
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<br/>
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==Contacts==
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One application of this vocabulary is that selected European marine species can be tagged with relevant attribute information and be made available through the World Register of Marine Species ([http://www.marinespecies.org/ WoRMS]) and the [http://emodnet-biology.eu/portal/ EMODnet biological portal].

[https://marineinfo.org/imis?module=person&persid=3361 Mark John Costello], University of Auckland, New Zealand; [https://marineinfo.org/imis?module=person&persid=8941 Dan Lear], Marine Biological Association, UK; [https://marineinfo.org/imis?module=person&persid=15644 Harvey Tyler-Walters], Marine Biological Association, UK; [https://marineinfo.org/imis?module=person&persid=26101 Stefanie Dekeyzer], Flanders Marine Institute, Belgium; Dmitry Schigel, GBIF, Denmark


==Acknowledgements ==
The Traits Hierarchy has been developed within the European Marine Observation Data Network (EMODnet) Biology project ([http://www.emodnet-biology.eu www.emodnet-biology.eu]), funded by the European Commission’s Directorate - General for Maritime Affairs and Fisheries ([http://ec.europa.eu/dgs/maritimeaffairs_fisheries/index_en.htm DG MARE]).<br/>
The Coastal Wiki Marine Species Traits software is based on the setup created by the Biodiversity Information Standards also known as the Taxonomic Databases Working Group ([http://terms.tdwg.org/wiki/ TDWG])

[[Category:Marine_species_traits]]

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Shoreline management

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{{Definition|title=Shoreline management
|definition=The act of dealing – in a planned way – with actual and potential coastal erosion and its relation to planned or existing development activities on the coast. The objectives of Shoreline Management are <ref name="Karsten">Mangor, K., Drønen, N. K., Kaergaard, K.H. and Kristensen, N.E. 2017. Shoreline management guidelines. DHI https://www.dhigroup.com/marine-water/ebook-shoreline-management-guidelines</ref>:
#To ensure the development activities in the coastal area follow an overall land use plan and a general environmental policy
#To ensure the development activities in the coastal area does not contribute to or aggravate erosion
#To ensure that development activities do not occur in sensitive areas
#To ensure that erosion control techniques are cost-effective and socially and environmentally acceptable
}}

This article provides an introduction to modern shoreline management, in the context of Integrated Coastal Zone Management. It describes general principles for drafting Shoreline Management Plans. Shoreline Management Planning in the UK is discussed as an example. Large parts of this article are taken from the coastal engineering handbook of Reeve, Chadwick and Fleming (2018)<ref> Reeve, D., Chadwick, A. and Fleming, C. 2018. Coastal Engineering: Processes, Theory and Design, Practice 3rd Edition. CRC press, 512 pp.</ref>.

==Pressures on the Coast==

Coastal areas have always been a popular place for recreation, habitation and commerce. Typical features include ports, marinas, fishing harbours, roads, railways, power stations, agriculture, recreational resorts, residential property, agriculture and a wide variety of natural habitats. In many parts of the world land immediately adjacent to the sea is significantly more valuable that elsewhere. It is therefore not surprising that that the coastal boundary is has been subject to both reclamation and protection in response to economic pressures. In many areas of the world there are soft eroding cliffs that experience erosion as well as low lying coastal plains that are vulnerable to both erosion and flooding due to the action of the sea. This coupled with gradually rising sea levels due to global warming has resulted in an increase in the shorelines around the world suffering from erosion. Moreover, the prospect of accelerating sea level rise and possible changes in the frequency and direction of storms presents a high degree of risk and uncertainty when it comes to considering the most appropriate design scenarios for coastal structures.

Global, regional and local issues such as sea level rise, the concentration of populations and tourism on the coast, and depletion and damage to valuable natural resources such as fisheries and wildlife, are making coastlines one of the most pressured and threatened environments in the world. Most of the world's major cities are at the coast, and more than 50% of the world's estimated 5.5 billion people live in coastal areas. It has been predicted that by 2020, 75% of the world's projected population of 8 billion could be living within 60 kilometres of the shoreline, the majority in developing nations.

This concentration of population at the coast is a result of a number of factors including:
* The diverse and productive renewable resources base in coastal areas which include fisheries, forests and fertile soils;
* Accessibility to maritime trade and transport routes through the construction of ports and harbours;
* Abundant and attractive recreational and tourism opportunities; and industrial investments such as power stations and oil/gas terminals;
* Increasing demands for residential property on or close to the coastal strip.

The demands made by this population concentration have caused problems such as:
* Over-exploitation of renewable resources like coastal fisheries, beyond sustainable yields;
* Degradation of coastal water and marine ecosystems from land-based pollution including sediment run-off, fertilizers and untreated sewage;
* Destruction of natural coastal habitats for construction or coastal aquaculture.

Coastal locations are also susceptible to a range of natural hazards such as [[Extreme storms|storm surges]], erosion and sea level change that can cause loss of life and property and damage to infrastructure, livestock and crops. Damage to the coastal infrastructure is often considered to be politically and economically unacceptable. However, in many circumstances it can no longer be assumed that defences should be maintained where they have previously existed. Through taking a strategic approach, there has been a significant change in the way that the design of coastal defences should be developed with the emphasis shifting from the provision of protection to managing the coastline in spatial scales that recognise the interactive nature of the processes that take place as well as over longer-term temporal scales. In doing so it is necessary to recognise that there is considerable uncertainty in defining all of the relevant parameters that can impact on the eventual outcome of adopting various policies so that management practices require a strategic approach that is largely based on risk analysis and continuous performance monitoring.

==Local Approaches==

Some design practices in the past, and in some places the present, might be classified as the ‘brute force’ approach. This is the principle that if a structure is big enough and strong enough it can withstand almost any of the conditions that it can be subject to with the exception of the most extreme events. However, this often takes no account of the morphological context in which the structure might exist. A further problem that seems to have persisted is that, whilst there have been significant advances in the appreciation of the interactions involved in regional coastal processes the physical areas of responsibility, and hence parochial interest, have been constrained to sub-areas of the [[Definitions of coastal terms#Sediment cell|coastal cell]]. In the event new works or repairs would be initiated as site-specific problems arose, sometimes as a result of ad-hoc monitoring. Interaction with adjacent sections of coastlines, and the constraint that they might impose would often only be considered in relation to the specific problem at the site. The result of this process would be that, whilst a particular problem might be solved with capital works, the wider implications of this action would not be addressed. Thus regional strategy, social planning and environmental management would not have been fully considered so that all the possible options could be explored. These would generally include measures to mitigate any potential downdrift erosion problems, preservation of natural habitats or recognition of alternative uses and enjoyment of the coastal environment.

The ad-hoc nature of this approach is unsatisfactory as it makes it extremely difficult to ensure that not only are schemes developed to be efficient and cost effective, but also natural process and natural resources are used to best effect in tandem with anthropological uses of the coastal area. The benefits of a more strategic approach to shoreline management should thus be easily appreciated.

==Strategic Approaches==

In many parts of the world, the idea of "Integrated Coastal Zone Management" (ICZM) is proposed as being a more satisfactory way forward. This is a process that goes beyond the traditional approach of planning and managing activities on an individual scheme basis. Instead, the aim is to focus on the combined effects of all activities taking place at the coast to seek suitable environmental and socio-economic outcomes. Sustainable use, with environmental considerations underlying decision making in all sectors of activity, provides the basis for this type of management. It is geared to dealing with the coastal environment as a whole - coastal land, the foreshore, and inshore waters - and is forward looking, as well as trying to resolve the problems of present day use of the coast.

Shoreline management is an important component of [[Integrated Coastal Zone Management (ICZM)]]. Principles of ICZM are summarised in the [[EU ICZM Recommendation|recommendations of the European Union on Integrated Coastal Zone Management]] and also discussed in [[The Integrated approach to Coastal Zone Management (ICZM)]]. ICZM involves the comprehensive assessment, setting of objectives, planning and management of coastal systems and resources, taking into account traditional cultural and historical perspectives, cumulative impacts, and conflicting interests and uses. It is a continuous and evolutionary process for achieving sustainable development through participation of the public and private sectors and with the support and interest of local communities.

==Recommendations==
When focusing on shoreline management, the following recommendations are relevant.
#A precondition for a successful shoreline restoration project is that all the parties involved have some understanding of coastal morphological processes; they are then in a position to understand why the present situation has developed and why certain solutions may work and others will not.
#Consider the coastal area as a dynamic natural landscape. Make only interventions in the coastal processes and in the coastal landscape if other interests of society are more important than preserving the natural coastal resource.
#Appoint special sections of the coast for natural development.
#Demolish inexpedient old protection schemes and re-establish the natural coastal landscape where possible.
#Minimise the use of hard coastal protection schemes, give high priority to the quality of the natural coastal resource.
#Preserve the natural variation in the coastal landscapes.
#Restrict new development/housing close to the coastline in the open uninhabited coastal landscape.
#Maintain and improve public access to and along the beach, legally as well as in practice.
#Reduce pollution and enhance sustainable utilisation of coastal waters.

==Practical guidelines for shore protection==

Below, the general recommendations are elaborated into practical guidelines for shore protection, shore restoration and sea defence projects.
#Work with nature, for instance by re-establishing a starved coastal profile by nourishment and by utilising site-specific features, such as strengthening (semi-)hard promontories.
#Select a solution which fits the type of coastline and which fulfils as many of the goals set by the stakeholders and the authorities as possible. It may be impossible to fulfil all goals, as they are often conflicting and because of budget limitations. It should be made clear to all parties, which goals are fulfilled and which are not. The consultant must make it completely clear what the client can expect from the selected solution; this is especially important if the project has been adjusted to fit the available funds.
#Propose a funding distribution that reflects the fulfilment of the various goals, set by the parties involved.
#Allow protection measures only if valuable buildings/infrastructure are threatened.
#Choose a protection scheme that preserves sections of untouched dynamic landscape where possible, for example by applying appropriate [[Shore protection vegetation|vegetation]].
#Use of a minimum number of hard structures required for achieving the protection objectives.
#Secure passage to and along the beach.
#Enhance the aesthetic appearance, e.g. by minimising the number of structures. Few and larger structures can be better than a lot of small structures.
#Preferably allow only projects which deal with an entire management unit/sediment cell and which secure maximum shore protection.
#Minimise maintenance requirements to a level that the owner(s) of the scheme is able to manage. A stand-alone nourishment solution may at first glance appear ideal, but it will normally not be ideal for the landowners, as recharge will be required at short intervals.
#Secure good local water quality and minimise the risk of trapping debris and seaweed.
#Secure safety for swimmers by avoiding structures generating dangerous [[rip current]]s. Avoid sheltered beaches ([[coves]]) as these give a false impression of safety for poor swimmers. Sheltered beaches may suffer from fine sediment trapping. If the water is too rough for swimming, a swimming pool, possibly in the form of a tidal pool, is a good solution.
#Provide good beach quality by securing that the beaches are exposed to waves, as wave action maintains attractive sandy beaches. This will of course limit the time that swimming is possible, but sheltered beaches often imply safety risks, poor beach quality and poor water quality.
#Be realistic and pragmatic, keeping in mind that the natural untouched coastline is utopia in highly developed areas. Create small attractive locations at otherwise strongly protected stretches if this is the only realistic possibility.

==Early Strategic Approach in the UK (Case Study)==

Formal shoreline management practices have been developing in the United Kingdom over the past twenty years or so. The Anglian Sea Defence Management Study (Fleming, 1989 <ref>Fleming, C. A. 1989. The Anglian Sea Defence Management Study. In Coastal Management. I.C.E. Thomas Telford, London, UK</ref>, Townend et al, 1990<ref>Townend, I.H. 1990. Frameworks for Shoreline Management, PIANC Bulletin No 71: 72-80</ref>) was the forerunner to the development of shoreline management plans (SMP’s) around the coastline of England and Wales. The Anglian coast is some 750 kilometres in length and the initial analysis of the coastline was based on the collation of a number of factors considered to influence the choice of management policy as listed in Table 1. These were selected on the basis that they either:
* provided information on the direct influences and responses of the coast such as waves, coastal morphology, and rate of retreat or
* provided information on their implications with respect to the impact of accretion/erosion and any defence strategy that might be implemented.
This list is not exhaustive and other influences might be found to occur in particular circumstances.

{| style=background:ivory; cellspacing=1px cellpadding=5px align=center width=100%
|+ Table 1. Factors Influencing Choice of Management Policy.
|- style="font-weight:bold; text-align:center; background:lightblue"
! width=10% style= border:2px solid ivory| Main Variable
! width=90% style= border:2px solid ivory| Significance
|-
| style="border:2px solid lightblue;text-align:center"| Agriculture
| style="border:2px solid lightblue;text-align:left"| Changes in habitat; Drainage patterns and run-off.
|-
| style="border:2px solid lightblue;text-align:center"| Birds
| style="border:2px solid lightblue;text-align:left"| Assessment of environmental impact.
|-
| style="border:2px solid lightblue;text-align:center"| Coastal movement
| style="border:2px solid lightblue;text-align:left"| Indicate areas of high/low activity; Assist with forecasting future movements; Relationship to sediment budget.
|-
| style="border:2px solid lightblue;text-align:center"| Conservation sites
| style="border:2px solid lightblue;text-align:left"| Special consideration to prevent undesirable changes.
|-
| style="border:2px solid lightblue;text-align:center"| Currents
| style="border:2px solid lightblue;text-align: left"| Influences sediment movement on offshore zones, links nearshore processes with far field effects.
|-
| style="border:2px solid lightblue;text-align:center"| Ecology
| style="border:2px solid lightblue;text-align: left"| A measure of shoreline (cliff, dune, saltmarsh) stability, shelter, relationship with rivers and estuaries; Assessment of environmental impact.
|-
| style="border:2px solid lightblue;text-align:center"| Fisheries
| style="border:2px solid lightblue;text-align: left"| Changes in habitat; Potential environmental impact.
|-
| style="border:2px solid lightblue;text-align:center"| Industry
| style="border:2px solid lightblue;text-align: left"| Coastal impact on processes and environment; Threat to habitats.
|-
| style="border:2px solid lightblue;text-align:center"| Morphology
| style="border:2px solid lightblue;text-align: left"| Basic description of coastline; Physical significance (eg offshore banks dissipate wave energy, cliffs can provide a sediment supply etc.); Width of foreshore indicates plan effects; Slopes control form of incoming waves; Indicates nature of sediment transport; Represents sediment sources and sinks; Intertidal features indicate beach cycles and on-shore movement.
|-
| style="border:2px solid lightblue;text-align:center"| Rainfall
| style="border:2px solid lightblue;text-align: left"| Influences groundwater levels and river discharges; Impact on sediment load in rivers; Impact on cliff stability.
|-
| style="border:2px solid lightblue;text-align:center"| Sediments
| style="border:2px solid lightblue;text-align: left"| Determines mobility of material; Forensic evidence for sources of materials; Basis for sediment budget.
|-
| style="border:2px solid lightblue;text-align:center"| Temperature
| style="border:2px solid lightblue;text-align: left"| Seasonal variations may contribute to erosion.
|-
| style="border:2px solid lightblue;text-align:center"| Water levels
| style="border:2px solid lightblue;text-align: left"| Major effect on coastal processes; Controls extent of wave influence on shoreline; Relates to potential for hinterland flooding.
|-
| style="border:2px solid lightblue;text-align:center"| Water quality
| style="border:2px solid lightblue;text-align: left"| Influences vegetation and hence shoreline stability; Impact on marine life and alteration of habitats; Density effects and transport regime.
|-
| style="border:2px solid lightblue;text-align:center"| Waves
| style="border:2px solid lightblue;text-align: left"| Fundamental to potential for shoreline erosion and accretion; Influences height and movement of offshore banks; Primary cause of infrastructure damage; Linked to climate change.
|-
| style="border:2px solid lightblue;text-align:center"| Wind
| style="border:2px solid lightblue;text-align: left"| Generates waves and storm surges; Governs subaerial erosion and deposition.
|}

The Anglian Sea Defence Management Project adopted an approach that involved collection of spatial and temporal data, such as shoreline position. These data were analysed using data mining techniques to provide insight into the behavioural trends of the coastline. Data were also supplemented by the use of numerical modelling of various coastal processes. The coastline was divided into management units which are sections of coastline that exhibit coherent characteristics in terms of baseline geology, natural processes, existing defences, foreshore type and land use. It was then attempted to link the coastal management strategy to the objectives that needed to be satisfied through consultation with a wide range of stakeholders. Shoreline policy options for the management units identified were simply described as:

* Maintain existing line
* Set back defence
* Retreat the defence line
* Advance or reclaim

On the face of it these options appear to be quite obvious and simplistic. However, it must be appreciated that a policy option selected on one section of coastline will invariably have an impact on the adjacent coastline and beyond. The first option applies to any existing line, which is being defended and will generally be preferred whenever there is a substantial investment in infrastructure on the coast. However, this option can be linked to a change in the standard of service of the defence. On an eroding coast set-back would be used to provide defences on the hinterland so that it is only necessary to defend against tidal inundation. The option could also be used to provide natural features ‘room to move’ (such as barrier beach and salt marsh systems), whilst retaining a level of defence against flooding. The retreat option was a managed withdrawal, allowing the coast to return to its natural state and could have been be an attractive option where the tidal floodplain was relatively narrow. It would also apply where no defence was to be provided on a naturally eroding coastline, but soft engineering expedients such as dune management, cliff drainage or beach management might be considered. Finally, the advance option allowed for the possibility of limiting low-lying exposure by suitable reclamation or the use of tidal barriers. The option that was chosen will be largely dependent on the existing infrastructure and erosion areas for any given length of coastline.

In order to implement any policy options it was proposed that various management options could be considered providing they were appropriate to the coastal classification. Those options were described as:

* Do nothing: let nature take its course
* Reinstate: beach renourishment, saltings regeneration, structural reconstruction etc.
* Modify: remove features or structures, structural alterations, stabilisation (cliffs/dunes/saltings) etc.
* Create: embayments, linear protection, intervention such as dredging, sand bypassing etc.

By defining policy options and management options for an entire coastline, the basis for a strategic management plan was established. It was recognised that, as actions based on this plan were to be undertaken, so aspects of the coastal characteristics would be modified and this, in time, was likely to alter the coastal classification.

The foregoing describes some of the formative basic principles behind the development of ‘shoreline management’ in the UK and is differentiated from ‘integrated coastal zone management’ which includes a very much wider range of considerations with respect to the use and sustainable development of the wider coastal zone. It is beyond the scope of this book to cover these wider issues

==Current UK SMP Approach(2011)==
The strategic approach to shoreline management in the United Kingdom has been driven and sponsored by the Department for the Environment, Food and Rural Affairs (DEFRA). The overall objective can be stated as (Burgess, 2002<ref>Burgess, K. 2002. Futurecoast – the integration of knowledge to assess the future coastal evolution at a national scale. Proceedings 28th Coastal Engineering Conference, ASCE New York</ref>):
''To reduce risks to people and the developed and natural environment from flooding and coastal erosion by encouraging the provision of technically, environmentally and economically sound and sustainable defence measures.''
In this context sustainable management approaches are those which:
''…..take into account the relationships with other defences, developments and processes………. And which avoid as far as possible tying future generations into inflexible and expensive options for defence.''

[[Image:UKcoastalcells.jpg|thumb|400px|right|Figure 1: Coastal cells as defined for the English coast.]]

In order to assist in this process the coastline of England and Wales was initially divided into a number of primary [[Definitions of coastal terms#Sediment cell|coastal cells]] and sub-cells which were defined as relatively self-contained units with respect to the movement of beach material <ref>Motyka, J.M. and Brampton, A.H. 1993. Coastal management: mapping of littoral cells HR Wallingford, Report SR328</ref>, see Figure 1. These are managed by groups that include representation from all of the authorities that have any statutory responsibility for coastline in the cell. The first round of SMPs to be developed provide the framework for defining the policy options that should be adopted in order to minimise the occurrence of flooding and coastal erosion in the context of sustainable development, whether related to the continuity of sediment transport processes or environmental conservation. At the same time the requirements of whatever legislation exists must be satisfied. The overall objectives of the shoreline management plan process are (Brampton, 2002<ref>Brampton, A., ed. 2002. Coastal defence, London: Thomas Telford</ref>):
* To define, in general terms, the risks to people and the developed, historic and natural environment within the shoreline management plan area;
* To define the natural processes taking place in terms of forcing functions (e.g. waves, tides, currents etc) and response (e.g. sediment movement, shoreline movement etc.);
* To define the potential retreat or advance of the shoreline within the statutory planning horizon of 70 years;
* To consult and conciliate with all of the users of the coastline in the area;
* To identify the preferred policies for managing these risks over the next 50 years;
* To identify the consequences of implementing the preferred policies;
* To set out procedures for monitoring the effectiveness of the shoreline management plan policies;
* To ensure that future land use and development of the shoreline takes due account of the risks and preferred shoreline management plan policies.

SMP guidance has evolved quite rapidly over the past decade since the first edition of this book was published in 2004. DEFRA(2006) <ref name=D> DEFRA 2006a. Shoreline management plan guidance Volume 1: Aims and requirements. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/69206/pb11726-smpg-vol1-060308.pdf</ref><ref>DEFRA 2006b. Shoreline management plan guidance Volume 2: Procedures. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/69207/pb11726v2-smpg-vol2-060523.pdf</ref> published a two volume document titled ‘Shoreline management plan guidance’. This describes an SMP as a large-scale assessment of the risks associated with coastal processes and helps to reduce these risks to people and the developed, historic and natural environment. The strategy should aim to manage risks by using a range of methods which reflect both national and local priorities, to:
* Reduce the threat of flooding and erosion to people and their property; and
* Benefit the environment, society and the economy as far as possible, in line with the Government’s ‘sustainable development principles’.

Thus, the SMP itself is intended to define the policy option, but not the precise physical form of the defence option. There will almost certainly be a number of generic solutions that will satisfy the requirements that have been identified in the SMP. There are further stages of study required to reach a final definitive scheme for implementation. Generic solutions will be identified through a Strategy Study for sections of coastline that have been identified as requiring remedial or new works. The final stage concerns a specific scheme for which a scheme specific study will compare alternative options and define the optimum scheme that best satisfies all of the technical, financial and socio-economic criteria that have been agreed. The overall framework is described in Table 2.

{| style=background:ivory; cellspacing=1px cellpadding=5px align=center width=70%
|+ Table 2. Stages in Assessing the Risks of Flood and Erosion<ref name=D></ref>.
|- style="font-weight:bold; text-align:center; background:lightblue"
! width="10% style=" border:1px solid blue;"| Stage
! width="20% style=" border:1px solid bleu;"| SMP
! width="20% style=" border:1px solid blue;"| Strategy
! width="20% style=" border:1px solid blue;"| Scheme
|-
| style="border:2px solid lightblue;text-align:center"| Aim
| style="border:2px solid lightblue;text-align:center"| To identify policies to manage risks
| style="border:2px solid lightblue;text-align:center"| To identify appropriate schemes to put the policies into practice
| style="border:2px solid lightblue;text-align:center"| To identify the type of work to put the preferred scheme into practice
|-
| style="border:2px solid lightblue;text-align:center"| Delivers
| style="border:2px solid lightblue;text-align:center"| A wide ranging assessment of risks, opportunities, limits and areas of uncertainty
| style="border:2px solid lightblue;text-align:center"| Preferred approach, including economic and environmental decisions
| style="border:2px solid lightblue;text-align:center"| Compare different options for putting the preferred scheme into practice
|-
| style="border:2px solid lightblue;text-align:center"| Output
| style="border:2px solid lightblue;text-align:center"| Policies
| style="border:2px solid lightblue;text-align:center"| Type of scheme ( such as a seawall)
| style="border:2px solid lightblue;text-align:center"| Design of works
|-
| style="border:2px solid lightblue;text-align:center"| Outcome
| style="border:2px solid lightblue;text-align:center"| Improve management for the coast over the long-term
| style="border:2px solid lightblue;text-align:center"| Management measures that will provide the best approach to managing floods and the coast for a specified area
| style="border:2px solid lightblue;text-align:center"| Reduce risks from floods and coastal erosion to people and assets
|}

Policy options were further detailed in the 2006 DEFRA <ref name=D></ref> guidance providing the following four SMP policies available to shoreline managers:
* '''Hold the existing defence line''' by maintainimg or changing the standard of protection. This policy should cover those situations where work or operations are carried out in front of the existing defences (such as beach recharge, rebuilding of the toe of a structure, building offshore breakwaters etc.) to improve or maintain the standard of protection provided by the existing defence line.
* '''Advance the existing defence line''' by building new defences on the seaward side of the original defences. This applies only to policy units where significant land reclamation is being considered.
* '''Managed Realignment''' by allowing the shoreline to move backwards or forwards, with management to control or limit the movement (such as reducing ersion or building new defences on the landward side of the original defences).
* '''No active intervention''' where there is no investment in coastal defences or operations.

The selection of the most appropriate policy option requires a clear focus on the assessment and management of coastal flooding and erosion risks over a one hundred year period beyond the initial appraisal so that there is a strong need for awareness of the longer-term implication of coastal evolution. There is also a clear need for a better appreciation of the uncertainties associated with predicting future shoreline management requirements coupled with a recognition that current defence policies may no longer be feasible or acceptable in the future.

DEFRA has encouraged the development of a strategic framework for flood and coastal erosion risk management based on Shoreline Management Plans (SMPs) and Catchment Flood Management Plans (CFMPs). These are high level plans, which have various relationships with other high level plans, strategies and schemes and other planning initiatives as shown schematically in Figure 2. These plans are based on a risk-based approach, giving more consideration to ‘risk management’ and ‘adaptation’ as opposed to only ‘protection’ and ‘defence’ as well as considering impacts within the whole of a catchment or shoreline process area.

[[Image:SMPscheme.jpg|thumb|500px|right|Figure 2: Relationship between high level plans, strategies, schemes and other planning initiatives <ref name=E></ref>.]]

More specific best practice guidance on how to undertake appraisals has been published by the Environment Agency (2010) <ref name=E> Environmental Agency 2010. Flood and Coastal Erosion Risk Management appraisal guidance. https://www.gov.uk/government/publications/flood-and-coastal-erosion-risk-management-appraisal-guidance</ref>. This was a collaborative project between the Environment Agency and the Maritime Local Authorities in England and Wales. It is a comprehensive document and justifiably describes itself as a single reference point for information that currently exists on the coast and its aim is to help and guide practitioners in managing the coast. Whilst intended as a technical guide for all operating authorities, it is essential reading for any practitioner involved in managing the coastline in these and any other regions. A useful review of coastal risk management and adaptation as part of sustainable shoreline management in England and Wales is also provided by Pontee and Parsons (2010<ref>Pontee, N.I. and Parsons, A. 2010. A review of coastal risk management in the UK. Proceedings of the Institution of Civil Engineers, Maritime Engineering Journal UK 163: 31-42</ref>, 2012<ref>Pontee, N.I. and Parsons, A. 2012. Adaptation as part of sustainable shoreline management in England and Wales. Proceedings of the Institution of Civil Engineers, Maritime Engineering Journal UK 165: 113-130</ref>).

Whilst these frameworks have been largely developed in this form in the UK they are equally applicable, in principle, to any region of the world. The outcome of the final stage focuses on the scheme appraisal process and also defines the type of structure or management strategy that should be adopted.

Legislation and required procedures will vary from country to country, so it is not possible to cover all of the possibilities in this article. However, a common theme of any modern day practice does focus on the need to properly carry out the appropriate planning steps, which include appropriate risk analyses leading to project optimisation. The new Coastal Engineering Manual Part V, Coastal Project Planning and Design <ref>USACE 2012. Coastal Engineering Manual. USACE, 2012. Coastal engineering manual. Report No 110-2-1100. Washington DC: US Army Corps of Engineers https://www.publications.usace.army.mil/USACE-Publications/Engineer-Manuals/u43544q/636F617374616C20656E67696E656572696E67206D616E75616C/ </ref> provides both a general framework as well as information that relates to procedures in the USA.

== Adaptation to climate change==

The general principles of modern coastal management, can be applied in any part of the world, although there will always be a regional context, which will mould the application of the general principles. The many issues surrounding predicted climate change have added another layer of complexity to coastal management, which are now being seriously addressed in terms of future management. One key aspect of coastal management includes identifying and quantifying coastal hazards and climate change impacts to assess coastal vulnerability. This can best be achieved by carrying out a comprehensive risk assessment to assess system reliability, using probability methods. Coastal management is then faced, inter alia, with determining policies and practices for adaptation (e.g. hard and soft engineering, managed re-alignment, no active intervention) in response to coastal vulnerability.
Many of the recent developments in coastal management have originated in the UK and other European coastal states and in North America. The UK in particular has an extremely varied coastal geomorphology, experiences large variations in waves, tides, water levels and currents, and is relatively densely populated. It is perhaps not surprising therefore, that many developments in coastal management have been initiated in the UK and embedded in central government policies for allocation of resources to coastal defences in the UK. It should, however, be noted that the UK is not routinely subject to nature’s most extreme weather found in hurricanes or exposure to [[tsunami]] events, which are so detrimental in other parts of the world.

==An example of adaptation to climate change in Barbados (Case Study)==

[[Image:BoardwalkBarbados.jpg|thumb|400px|right|Figure 3: View of the Boardwalk scheme in Barbados.]]

The Coastal Zone Management Unit (CZMU) of Barbados has adopted these approaches to address coastal erosion and flooding caused by past development activity and now potentially climate change and sea level rise, as described in detail by Mycoo and Chadwick (2012) <ref>Mycoo, M. and Chadwick, A. 2012. Adaptation to Climate Change: The Coastal Zone of Barbados. Maritime Engineering, UK 165: 159-168</ref>.
One pioneering example from Barbados is the combination of hard and soft engineering, green architecture, and landscaping in some coastal locations. Examples of more recently built seawalls in combination with mini-headlands and groynes are those along the beach face at Welches in Christ Church and Rockley Beach. These structures have minimised erosion and increased beach accretion along certain parts of the coast. They have also reduced the vista of a highly engineered shoreline through the integration of aesthetically pleasing boardwalks and landscaping that help the beach look more natural rather than artificial in appearance (see Figure 3). In addition, the seawall and boardwalk have become multifunctional in that they are for not only coastal protection, but provide access to other beaches. Additionally, locals ply their souvenirs or use them for leisurely walks and exercise.

==Related articles==
:[[Integrated Coastal Zone Management (ICZM)]]
:[[Shore nourishment]]
:[[Dune stabilisation]]
:[[Shore protection vegetation]]
:[[Ecological enhancement of coastal protection structures]]
:[[Climate adaptation measures for the coastal zone]]
:[[Coastal cities and sea level rise]]
:[[Policy instruments for integrated coastal zone management]]
:[[Hard coastal protection structures]]
:[[Dealing with coastal erosion]]
:[[Human causes of coastal erosion]]
:[[Natural causes of coastal erosion]]

==Further reading==
[https://www.nature.scot/beach-dunes-guide-managing-coastal-erosion-beach-dune-systems Publication 2000 - Beach Dunes - a guide to managing coastal erosion in beach dune systems]

==References==
<references/>

<div style = "float: center"> <div align="center">
{| style="border:1px solid #abd5f5; background:#f1f5fc; margin:0em 0em 0em 5em;"
|<center>The authors of this article are [https://marineinfo.org/imis?module=person&persid=11189 Andrew Chadwick], [https://marineinfo.org/imis?module=person&persid=13423 Dominic Reeve], [https://marineinfo.org/imis?module=person&persid=13372 Christopher Fleming], [https://marineinfo.org/imis?module=person&persid=13331 Karsten Mangor] and
[https://marineinfo.org/imis?module=person&persid=13036 Caitlin Pilkington] </center>
|}

[[Category:Coastal protection]]
[[Category:Hard structures]]
[[Category:Soft coastal interventions]]
[[Category:Climate change, impacts and adaptation]]
[[Category:Integrated coastal zone management]]

Sediment deposition and erosion processes

2026-11-10T12:00:50Z

Admin: Text replacement - "http://www.coastalwiki.org/imis/imis.php?module=person&persid=" to "https://marineinfo.org/imis?module=person&persid="

Sediment deposition and erosion are fundamental processes governing the transport and redistribution of sediment in estuaries and coastal waters. Deposition occurs when sediment particles settle from suspension onto the bed, whereas erosion involves the detachment and entrainment of bed material by currents and waves. Both processes can occur simultaneously; their relative rates determine whether the bed experiences net accretion or erosion.

Sediment behaviour depends strongly on particle properties and interactions. Sand grains are generally transported as individual particles, whereas fine-grained sediment may form cohesive aggregates (flocs) whose size, density and settling velocity depend on sediment composition, concentration, biological binding and turbulence. After deposition, cohesive sediment may consolidate and gain strength, while at high concentrations it may form fluid mud that can flow or be entrained into the overlying water.

This article reviews the physical mechanisms of settling, deposition and erosion for cohesionless and cohesive sediments. Particular attention is given to flocculation, hindered settling, fluid mud, sediment-bed exchange and the empirical relationships used to quantify these processes. The influence of biological processes on sediment stability is discussed further in [[Biogeomorphology of coastal systems]].

==Introduction==

Deposition and erosion are the two basic processes inherent to the movement of sedimentary particles in estuaries. As these processes determine the advective sediment load, understanding their mechanics is essential for load prediction. To begin with prevalent classifications related to particle diameter are summarized on a comparative basis. Estuarine sediment usually includes a continuous distribution of diameter from coarse-grained, commonly sand, to fine-grained including silt, clays and colloids. It is therefore useful to review coarse and fine sediment properties and transport behaviors in tandem. The definition of particle size related to settling velocity is introduced in the context of cohesionless particles as well as cohesive particles present as flocs. A separate description is given for the settling velocity of flocs as their diameter and density depend on particle concentration and flow turbulence. The basis of deposition and erosion is described in terms of commonly used mass flux functions. Simple analytical methods for sediment load are referenced, and for cohesive flocs the significance of fluid mud is illustrated in terms of its entrainment potential.

==Classification==

In Table 1 five classifications based on particle properties and empirically related to diameter are given. The diameters range from 10 mm for sand (for which the upper limit is 64 mm) down to 0.001 μm (1 nm) for colloidal particles. In between are silt and clay particles. Designations such as sand/silt, etc. refer to boundary diameters. In regard to particle type, only suspended particles which settle in a reasonable period of time are classified as sedimentary. Thus colloidal particles do not constitute sediment. However, as clay particles in the range of 1 to 0.1 μm are often found in flocs they are conveniently designated as sedimentary as well as colloidal.

[[Image:MehtaNewTable1.jpg|thumb|900px|center| Table 1. Particle classifications by property.]]

In soil, only clay minerals possess electrochemical cohesion. The median diameter of the size distribution is typically in the range of 1-2 μm and the spread is about 0.1 to 10 μm, which does not match the soil-based classification in Table 1. This is because soil is conventionally classified by plasticity (not cohesion) as coarse-grained and fine-grained with a break at 62.5 μm at the sand/silt boundary.

The mean threshold diameter <small><math>d_T</math></small> of about 10 μm separating cohesive particles and larger cohesionless particles has been deduced from the experiments of Migniot<ref name=Mi> Migniot, C. (1968) A study of the physical properties of different very fine sediments and their behavior under hydrodynamic action, La Houille Blanche, 7, 591-620 (in French, with abstract in English).</ref> on the settling of twenty-seven fine-grained sediments (natural and clay minerals) and a compilation of data by McCave et al.<ref name=Mc>McCave, I.N., Manighetti, B., Robinson, S.G. (1995) Sortable silt and fine sediment size/composition size slicing: parameters for palaeocurrent speed and palaeoceanography. Paleoceanography, 10, 593-610.</ref> on the erosion of beds of kaolinite flocs and fine-grained quartz (< 62.5 μm) particles. Phenomenological arguments (Mehta and Letter <ref name=ML15> Mehta, A.J., Letter, J.V., Jr., (2015). Cohesive/cohesionless sediment transition diameter from settling velocity data, Ocean Dynamics, DOI 10.1007/s10236-015-0865-3.</ref>) suggest that <math>d_T</math> may be related to the physicochemical properties of clays in water yielding

<math>{{d}_{T}}=\Large [\frac{{{A}_{H}}{{\lambda }_{T}}}{4\pi g\Delta {{\rho }_{s}}\delta _{\kappa }^{2}}] ^{0.5} \normalsize , \qquad(1)</math>

where <math>A_H</math> is the Hamaker constant characterizing van der Waals interaction between the particles, <math>\lambda_T</math> represents the ratio of floc-scale electrochemical cohesion to the van der Waals attraction between clay particles, <math>g</math> is the acceleration due to gravity, <math>\Delta \rho_s= \rho_s-\rho_w</math> is the excess material density of particles, <math>\rho_s</math> is the material density, <math>\rho_w</math> is the water density and <math>\delta_{\kappa}</math> is the thickness of the ionic double layer surrounding the clay particle (van Olphen<ref name=VO>van Olphen, H. (1977). An Introduction to Clay Colloid Chemistry, 2nd ed., Wiley.</ref>). For clay minerals in water, nominal values of <math>\Delta \rho_s= 1,650 \;</math> kg m<sup>-3</sup>, <math>\delta_{\kappa} = 4 \times 10^{-8} \;</math> m, <math>A_H = 10^{-20} \;</math> N m and <math>\lambda_T = 3.25</math> are consistent with <math>d_T = 10 \;</math> μm.

Flocs contain multiple mineral particles of generally much smaller diameters (van Olphen<ref name=VO></ref>). They are watery with buoyant weights much lower than that of the mineral, which typically has a wet bulk density in the vicinity of <math>2,650\;</math> kg m<sup>-3</sup>. Flocs larger than about 100 μm are notionally called macroflocs and those smaller microflocs (e.g. Eisma<ref name=Eis> Eisma, D. (1986). Flocculation and de-flocculation of suspended matter in estuaries, Netherlands Journal of Sea Research, 20(2/3), 183-199.</ref>). Microflocs smaller than about 1 μm are generally not of direct major interest to sedimentation engineering. Natural flocs almost always contain organic detritus in variable proportions from practically nil to 100% by weight. Their light weight and the biochemical bonding they provide can substantially influence floc properties (e.g. Gerbersdorf et al. <ref name=G> Gerbersdorf, S.U., Bittner, R., Lubarsky, H., Manz, W. and Paterson, D.M. (2009). Microbial assemblages as ecosystem engineers of sediment stability, Journal of Soils and Sediments, 9, 640-652.</ref>).

The transition between cohesionless and cohesive sediment behaviour depends on particle size, mineral composition and interparticle bonding. For individual mineral particles, a transition diameter of approximately 10 μm has been proposed by Mehta and Letter (2015<ref name=ML15/>). However, this value is not a universal boundary. The applicability of cohesive or cohesionless sediment transport formulations depends on the composition and aggregation state of the sediment and on the cohesive properties of the bed.

==Particle Diameter Determination==

===Diameter definition===

Particle size is conventionally defined by the fall diameter, i.e., the diameter of a sphere having the same fall or settling velocity <math>{w}_{s}</math> as that of the real particle in water formally at °C. Most commonly the fall diameter is the diameter obtained by measuring <math>{w}_{s}</math> in quiescent water.

===Cohesionless particles===

[[Image:MehtaFig1.jpg|thumb|500px|right| Figure 1. Particle diameter as a function of settling velocity for quartz spheres (Rouse<ref name=Rou> Rouse, H. (1937). Nomogram for the settling velocity of spheres, Exhibit D, Report of the Commission on Sedimentation 1936-37, Division of Geology and Geography, National Research Council, Washington DC, 57-64.</ref>) and Stokes law.]]

For cohesionless particles the diameter <math>d_p</math> is related to <math>w_s</math> by the general form of Stokes law

<math>{{d}_{p}}= \Large \frac{3{{C}_{D}}(\operatorname{Re}){{\rho }_{w}}w_{s}^{2}}{4g\Delta {{\rho }_{s}}} \normalsize , \qquad(2)</math>

where <math>C_D(\operatorname{Re})</math> is the drag coefficient, a function of the fall Reynolds number <math>\operatorname{Re}</math> defined as

<math>\operatorname{Re}=\Large \frac{{{\rho }_{w}}{{w}_{s}}{{d}_{p}}}{\eta } \normalsize , \qquad(3)</math>

with <math>\eta</math> the dynamic viscosity of water (Julien<ref name=J> Julien, P.Y. (2010). Erosion and Sedimentation, 2nd ed., Cambridge.</ref>). When the flow surrounding the falling particle is viscosity-dominated <math>(\operatorname{Re} \le 0.1) \; C_D = 24/\operatorname{Re}</math>, so Eq. (2) becomes

<math>{{d}_{p}}= \Large [\frac{18\eta {{w}_{s}}}{g\Delta {{\rho }_{s}}}]^{0.5} \normalsize. \qquad(4)</math>

For quartz spheres in water at <math>20^{\circ}</math>C <math>\; (\rho_w = 1,000 \;</math> kg m<sup>-3</sup>), Fig. 1 shows experiment-derived variation of <math>d_p</math> with <math>w_s</math> (Rouse<ref name=Rou></ref>). In this case, for practical purposes the threshold value of <math>\operatorname{Re}</math> is taken as 1, which means that Eq. (4) can be used to obtain <math>d_p</math> from <math>w_s</math> below this threshold, as determined by the line extending down to about 0.01 mm (10 μm). When <math>\operatorname{Re} > 1</math> Eq. (4) underpredicts the diameter and Eq. (2) must be used with <math>C_D(\operatorname{Re})</math> obtained from the experimentally based plot (not included) for particles of different shapes (see, e.g. Julien<ref name=J></ref>). Note however that the quartz sphere curve is reasonably accurate for natural sand particles even though they are usually not quite spherical.

===Cohesive flocs===

[[Image:MehtaFig2.jpg|thumb|400px|right| Figure 2. Floc excess (bulk) density against diameter based on flocculator experiments reported in Lick<ref name=Lick> Lick, W. (2009). Sediment and Contaminant Transport in Surface Waters, CRC Press.</ref>.]]

Clay mineral particles in the range of 10 to 0.1 μm are present in flocs. The floc diameter <math>d_f</math> is determined by aggregation (processes) including floc growth and breakup. Floc growth depends on the particle-particle collision frequency which in turn is contingent upon the concentration of particles and the collision mechanism.
[Comment J. Dronkers: The omnipresence of extracellular polymeric substances (EPS) and bacteria in seawater also plays an important role in flocculation processes, see [[Coastal and marine sediments#Flocculation|flocculation]]].
Turbulent shear represented by the rate <math>G</math> is the main collision mechanism in estuarine waters except during times close to [[slack water]] when collisions are promoted by flocs settling at different velocities and to a lesser extent by Brownian diffusion (Winterwerp and van Kesteren<ref name=WK4> Winterwerp, J.C., van Kesteren, W.G.M. (2004). Introduction to the Physics of Cohesive Sediment in the Marine Environment. Elsevier.</ref>). Note that Brownian diffusion does play an important role in the aggregation of colloids, which can become large enough to be in the sedimentary size range (Mayer and Wells<ref name=MW> Mayer, L.M., Wells, M.L. (2011). Aggregation of colloids in estuaries, In: Wolanski E. and McLusky D.S. eds.,Treatise on Estuarine and Coastal Science, Vol. 4, Academic Press, 143-159.</ref>). Shear produces strong flocs compared to the other two mechanisms and its role is manifested as dependence of floc diameter on the Kolmogorov micro-length scale of turbulent eddies (Liggett<ref name=Lig> Liggett, J.A. (1994). Fluid Mechanics, McGraw-Hill.</ref>, Fugate and Friedrichs<ref name=FF> Fugate, D.C., Friedrichs, C.T. (2003). Controls on suspended aggregate size in partially mixed estuaries, Estuarine Coastal and Shelf Science, 58, 389-404.</ref>). Floc breakup occurs when high-velocity collisions induce a stress that exceeds the shear strength of the floc, and in the absence of collisions by flow-induced shearing.

Whether the diameter <math>d_f</math> increases or decreases with time <math>t</math> is determined by the balance

<math>\Large \frac{d}{dt} \normalsize {{d}_{f}} = \text{rate}\ \text{of}\ \text{growth}\,\text{-}\,\text{rate}\ \text{of}\ \text{breakup}.\qquad (5)</math>

Kranenburg <ref name=Kra> Kranenburg, C. (1994). The fractal structure of cohesive sediment aggregates, Estuarine Coastal and Shelf Science, 39(5), 451-460.</ref> argued that clay flocs demonstrate fractal properties reasonably well, i.e. their structures are geometrically fairly similar, as defined by the fractal dimension <math>D</math>. Under this assumption the above equation can be represented as (Winterwerp and van Kesteren<ref name=WK4></ref>)

<math>\Large \frac{d}{dt} \normalsize {{d}_{f}} =\ {{k}_{g}}{{\rho }_{s}}{{\phi }^{n}}Gd_{f}^{2}-\ {{k}_{b}}{{G}^{3/2}}d_{f}^{2}({{d}_{f}}-{{d}_{p}}), \qquad (6)</math>

in which <math>D</math> is taken as 2, a typical mean value, <math>\phi= C/\rho_s</math> is the solids volume fraction, <math>C</math> is the sediment concentration (in units of, e.g., kg m<sup>-3</sup>), <math>k_g</math> and <math>k_b</math> are sediment dependent growth and breakup coefficients, respectively, and <math>n</math> embodies the intensity of aggregation as mentioned again later. Son and Hsu<ref name=SH11> Son, M., Hsu, T.-J. (2011). The effects of flocculation and bed erodibility on modeling cohesive sediment resuspension, Journal of Coastal Research, 116, C03021, doi:10.1029/2010JC006352</ref> proposed a modified form of Eq. (6) by relaxing the restriction that the floc yield strength and the fractal dimension are constant.

Starting with seed mineral particles, under conditions that promote growth, <math>d_f</math> will increase and eventually reach an equilibrium value <math>d_{fe}</math> when the growth and breakup rates become equal. In that case <math>d d_f /d t = 0 </math> and from Eq. (6)

<math>{{d}_{fe}}= \Large\frac{{{k}_{g}}}{{{k}_{b}}}\frac{{{\rho }_{s}}}{\sqrt{G}} \normalsize {{\phi }^{n}}, \qquad (7)</math>

where we have assumed <math>d_p/d_{fe} << 1</math>, which is typically reasonable. This relationship indicates that <math>d_{fe}</math> varies with <math>{\phi}</math> as well as <math>G</math>. The equilibrium floc diameter predicted by Eq. (7) is attained only when hydrodynamic and sediment conditions remain sufficiently constant for the aggregation–breakup balance to develop. Under rapidly varying tidal conditions, the actual floc size distribution may lag behind the equilibrium distribution.

The wet bulk density <math>\rho_f</math> of flocs is usually much lower than the material density <math> \rho_s</math>, hence Stokes law [Eq. (4)] can be restated as

<math>{{d}_{f}}= \Large [\frac{18\eta {{w}_{s}}}{g\Delta {{\rho }_{f}}}]^{0.5} \normalsize , \qquad (8)</math>

in which the diameter <math>d_{fe}</math> is simply denoted as <math>d_f</math> and <math>\Delta \rho_f = \rho_f - \rho_w</math> is the excess floc density. From this and image-based measurements of <math>w_s</math> and <math>d_f</math> in a settling column <math>\Delta \rho_f</math> can be calculated.

Very few sets of experimental data appear to be available in which <math>d_f</math> is measured systematically over variable <math>G</math> and <math>\phi</math>. As observed from the laboratory data on sediment from the Detroit River in Fig. 2, as <math>d_f</math> increases <math>\Delta \rho_f</math> decreases and the flocs become increasingly porous (Lick<ref name=Lick></ref>). These data were obtained in flocculators - a rotating cylinder flocculator in which the flocs grew due to shearing, and a disc flocculator in which they grew by differential settling (<math>G = 0</math>). The mean trends from the rotating flocculator can be expressed roughly as

<math>{{d}_{f}}=\Large \frac{A(G)}{\Delta \rho _{f}^{3/4}} \normalsize , \qquad (9)</math>

with <math>A(G)</math> values given in the plot. At a constant <math>\Delta \rho_f</math>, <math>d_f</math> increases with <math>G</math>, which means that within the range of <math>G = 100-400 \; </math> s<sup>-1</sup> floc growth is promoted with increasing flow shear. As a rule, at such high shear rates (<math>G > 100 \;</math> s<sup>-1</sup>) breakup tends to dominate and scatters large flocs into smaller units (McAnally<ref name=McA> McAnally, W.H. (1999). Transport of fine sediments in estuarial waters, PhD Thesis, University of Florida, Gainesville.</ref>). This suggests that the effective shear rate in the flocculator may have been substantially lower than the value calculated from the angular velocity of the rotating cylinder. The data from the disc flocculator indicate that large diameter flocs were produced in the absence of shear-induced aggregation. In this case the exponent of <math>\Delta \rho_f </math> is, very approximately, <math>-1</math> indicating a somewhat different trend than Eq. (9).

==Settling Velocity==

===Cohesive flocs===

To obtain the settling velocity of flocs, Eq. (2) may be restated as

<math>{{w}_{s}}= \Large [\frac{4g\Delta {{\rho }_{f}}{{d}_{f}}}{3{{\rho }_{w}}{{C}_{D}}(\operatorname{Re})}]^{0.5} \normalsize. \qquad (10) </math>

For fractal flocs, mass balance dictates that (Kranenburg<ref name=Kra></ref>)

<math>\Delta {{\rho }_{f}}=\Delta {{\rho }_{s}}{{\left( d_f / d_p \right)}^{D-3}}. \qquad (11)</math>

From Eqs. (10) and (11)

<math>{{w}_{s}}=\Large \frac{ g \Delta { {\rho }_{s} } } {{18\eta (1+X) } d_{p}^{D-3}} \normalsize d_{f}^{D-1}, \qquad (12)</math>

which includes the substitution

<math>{{C}_{D}}=\Large \frac{24(1+X)}{\operatorname{Re}} \normalsize , \qquad (13)</math>

where the correction factor <math>X</math> permits an extension of Stokes law to <math>\operatorname{Re}</math> well above <math>1</math>. Winterwerp<ref name=Win> Winterwerp, J.C. (1998). A simple model for turbulence induced flocculation of cohesive sediment, Journal of Hydraulic Research, 36(3), 309-326.</ref> selected <math>X = 0.15 \operatorname{Re}^{0.687}</math>, which is valid up to <math>\operatorname{Re} < 800</math>.

A restriction on Eq. (12) is that it is applicable to settling under quiescent conditions only. In order to account for the effect of flow shear Eqs. (7), (8) and (11) with <math>D=2</math> are combined to yield

<math>{{w}_{s}}=a(G){{\phi }^{n}}, \qquad (14)</math>

where

<math>a(G)=\Large \frac{g{{\rho }_{s}}{{d}_{p}}\Delta {{\rho }_{s}}{{k}_{g}}}{18\eta {{k}_{b}}\sqrt{G}} \normalsize , \qquad (15)</math>

in which <math>k_g</math> and <math>k_b</math> can be functions of <math>G</math>. As they are generally unknown, van Leussen<ref name=VL> van Leussen, W. (1994). Estuarine macroflocs: their role in fine-grained sediment transport, PhD thesis, Utrecht University, the Netherlands.</ref> and others introduced the following expression revised from Eq. (14)

<math>{{w}_{s}}={{w}_{sh}}(G) \Large {{\left( \frac{\phi }{{{\phi }_{h}}} \right)}^{n}} \normalsize ;\quad {{w}_{sh}}(G)={{a}_{0}} \Large \left( \frac{1+{{\lambda }_{a}}G}{1+{{\lambda }_{b}}{{G}^{2}}} \right) \normalsize ;\quad \Large \frac{\phi }{{{\phi }_{h}}} \normalsize \le 1 , \qquad (16)</math>

where <math>w_{sh}(G)</math> is the maximum settling velocity at the onset of hindered settling when the volume fraction is <math>\phi_h</math>, and the constants <math>a_0,\; n,\; \lambda_a, \; \lambda_b</math> are independent of <math>G</math>. This expression is valid in the range <math>\phi \le \phi_h</math>. The lowest applicable value of <math>\phi</math> can be conveniently selected to correspond to the lowest experimental concentration <math>C</math> of suspended sediment.

Setting <math>G = 0</math> yields

<math>{{w}_{s}}={{w}_{sh}} \Large{{\left( \frac{\phi }{{{\phi }_{h}}} \right)}^{n}} \normalsize . \qquad (17)</math>

[[Image:MehtaFig3.jpg|thumb|600px|right| Figure 3. Variation of floc settling velocity with volume fraction and shear rate. Lines are from Eq. (16); data are from Manning<ref name=Man1> Manning, A.J. (2001). A study of the effects of turbulence on the properties of flocculated mud. Ph.D. Thesis, University of Plymouth, Plymouth, UK.</ref>.]]

A similar formula was derived empirically by Krone<ref name=K62> Krone, R.B. (1962). Flume studies of the transport of sediment in estuarial shoaling processes, Final Report, Hydraulic Engineering Laboratory and Sanitary Engineering Research Laboratory, University of California, Berkeley.</ref> with values of <math>w_{sh}</math> and <math>n</math> independent of <math>G</math> deduced from settling tests on the flocs of San Francisco Bay sediment in a graduated glass cylinder. It was shown that Eq. (17) is consistent with the kinetics of inter-particle collisions and aggregation during the settling of suspended flocs previously postulated by Overbeek<ref name=O> Overbeek, J.T.G. (1952). Colloid Science, Vol. 1, in: Kinetics of Flocculation, H.R. Kruyt ed., Elsevier, 278-300.</ref>, with <math>n = 4/3</math>.

Returning to Eq. (16), in Fig. 3 field-collected data from a station in the Tamar estuary (UK) are included for two tidal conditions – high spring and neap (Manning <ref name=Man1></ref>) – using an apparatus consisting of two components – LabSFLOC (Manning<ref name=Man6> Manning, A.J. (2006). LabSFLOC – A laboratory system to determine the spectral characteristics of flocculating cohesive sediments, Technical Report TR 156, HR Wallingford, Wallingford UK.</ref>) and INSSEV (Manning and Dyer<ref name=MD> Manning, A.J. and Dyer, K.R. (2002). The use of optics for the in-situ determination of flocculated mud characteristics, Journal of Optics A: Pure and Applied Optics, 4, S71-S81.</ref>), which together permit optical image-based measurements of the settling velocity and the diameter as flocs fall in a column. The apparatus is taken on board the vessel and measurements are made immediately upon retrieving a sample of suspension at the desired depth below water surface. The shear rate is calculated from

<math>G= \Large [\frac{{{\rho }_{w}}u_{*}^{3}}{\kappa \eta {{z}_{b}}}]^{0.5} \normalsize , \qquad (18)</math>

where <math>u_*</math> is the known bed friction velocity, <math>\rho_w= 1,015 \;</math> kg m<sup>-3</sup>,<math>\; \kappa = 0.4</math> is the von Karman constant, <math>\eta = 1.02 \times 10^{-3} \;</math> Pa.s and <math>z_b = 0.25 \;</math> m is the nominal near-bed elevation representing the sampling depth. Values of the coefficients for lines from Eq. (16) are <math>a_0 = 10^{-4}, \; \phi_h = 3.2 \times 10^{-3}, \; \lambda_a = 10, \; \lambda_b = 0.01, \; n = 1/3</math>. The <math>n</math> value is consistent with <math>0.344 </math> obtained from data on the settling of flocs of sediment from the San Francisco Bay in laboratory flumes, even though the hydraulic conditions were not entirely comparable with those in the bay (Mehta et al. <ref name=M14> Mehta, A.J., Manning, A.J., Khare, Y.P. (2014). A note ob the Krone deposition equation and significance of floc aggregation, Marine Geology, 354, 34-39.</ref>). The value <math>1/3</math> is also supported by data from other estuaries (Winterwerp and van Kesteren<ref name=WK4></ref>). For fixed values of <math>G</math> (from <math>1</math> to <math>50</math> s<sup>-1</sup>), <math>w_s</math> characteristically increases with <math>\phi</math> as collisions between flocs/particles increase with particle concentration. The fifty-five data points for neap tide yield <math>2.34</math> as the mean fractal dimension <math>D</math> with a standard deviation <math>\sigma_D = 0.11</math>. The 50 spring tide data points give <math>D = 2.32</math> and <math>\sigma_D = 0.08</math>. From this we may infer that variation in the tidal range did not have a significant impact on floc geometry.

[[Image:MehtaFig4.jpg|thumb|500px|right| Figure 4. Variation of floc settling velocity with shear rate and volume fraction. Curves are calculated from Eq. (16); data are from Manning<ref name=Man1></ref>.]]

In Fig. 4 the Tamar data are replotted to emphasize the role of <math>G</math> at constant <math>\phi</math> ranging from <math>3.0 \times 10^{-6}</math> to <math>5.5 \times 10^{-4}</math> consistent with measured concentrations of suspended sediment. As turbulence increases, at <math>G = 9.9 \approx 10 \;</math> s<sup>-1</sup> the growth and breakup processes balance and <math>w_s</math> attains a maximum. Further increase in <math>G</math> results in the dominance of breakup and <math>w_s</math> decreases. Data below about <math>1 \;</math> s<sup>-1</sup> suggest that at these low shear rates <math>w_s</math> is not clearly dependent on <math>G</math>. As the provenance of these low shear flocs is unknown it is reasonable to consider <math>1 \;</math> s<sup>-1</sup> to be the lowest value of <math>G</math> at which Eq. (16) describes shear-induced aggregation.

Flocculation is also strongly influenced by organic matter and microbial activity. Extracellular polymeric substances (EPS), produced by microorganisms, promote particle adhesion and influence the structure, density and strength of flocs. Consequently, flocculation behavior depends not only on sediment concentration and turbulence but also on sediment composition and biological conditions; see [[Flocculation cohesive sediments]].

===Hindered settling===

Hindered settling, which begins when <math>\phi</math> exceeds <math>\phi_h</math>, is manifested as a decrease in the settling velocity with increasing <math>\phi</math>. The particles are so close together that the rate at which they settle depends on the rate at which interstitial water can escape upward; this rate decreases as <math>\phi</math> increases (and flow permeability decreases). Strong vertical concentration gradients may develop, sometimes forming a lutocline. However, the occurrence and position of a lutocline also depend on turbulent mixing and density stratification.

According to Eq. (16) the maximum velocity achieved at the onset of hindered settling is dependent on the shear rate. To avoid this dependence Teeter<ref name=T> Teeter, A.M. (2001). Clay-silt sediment modeling using multiple grain classes. Part I: settling and deposition, In: Coastal and Estuarine Fine Sediment Processes, W.H. McAnally and A.J. Mehta eds., Elsevier, 157-171.</ref> modified Eq. (16) to ensure that the five <math>w_s (\phi)</math> curves in Fig. 3 have different slopes and converge to a single value of <math>w_s</math> at <math>\phi_h</math>. However, it is found that in general this modification renders the <math>w_s (\phi)</math> curve non-monotonic, which is unsupported by data.

[[Image:MehtaFig5.jpg|thumb|500px|right| Figure 5. Settling velocity as a function of volume fraction; data from Lake Apopka and curves from Eqs. (16) and (19).]]

The simplest model for hindered settling is the Richardson and Zaki<ref> Richardson, J.F., Zaki, W.N. (1954). The sedimentation of a suspension of uniform spheres under conditions of viscous flow, Chemical Engineering Science, 3, 65-73.</ref> equation (in adapted form)

<math>{{w}_{s}}={{w}_{sh}}(G){\Bigg[1-k\left( \Large \frac{\phi }{{{\phi }_{h}}} \normalsize -1 \right) \Bigg]^{5}} \; ; \Large \frac{\phi }{{{\phi }_{h}}} \normalsize \ge 1, \qquad (19)</math>

in which <math>k</math> depends on the sediment. The exponent 5 (rounded from the experimental 4.65) was shown by the investigators to be consistent with the correction to Stokes law derived by considering the forces on a free falling particle due to neighboring particles in the viscous regime. As <math>w_{sh}(G)</math> is not always known, it may be taken as <math>w_{sh}(1)</math> from Eq. (16), the lowest value arising from shear-induced aggregation, i.e.

<math>{{w}_{sh}}(1)={{a}_{0}} \Large \left( \frac{1+{{\lambda }_{a}}}{1+{{\lambda }_{b}}} \right) \normalsize . \qquad (20)</math>

In Lake Apopka in central Florida settling velocities of organic-rich mud (<math>\rho_s = 1,873 \;</math> kg m<sup>-3</sup>) were measured with LabSFLOC/INSSEV and also in a laboratory settling column. As shear rates in the lake were low, assuming <math>G = 1 \;</math> s<sup>-1</sup>, Eqs. (16) and (19) are plotted in Fig. 5 along with the data.

===Fluid mud===

[[Image:MehtaFig6.jpg|thumb|400px|right| Figure 6. Layered structure of flocculated sediment in water and in the bed.]]

Figure 6 shows sediment-stratified layers in water flowing over a bed of flocs formed by prior deposition of suspended matter. Concentration is conveniently specified by the floc volume fraction <math>\phi_f</math>, which is related to <math>\phi</math>by

<math>{{\phi }_{f}}=\Large \frac{\Delta {{\rho }_{s}}}{\Delta {{\rho }_{f}}} \normalsize \phi. \qquad (21) </math>

Setting <math>\phi_f= 1</math> in Eq. (21) defines the so-called space-filling volume fraction <math>{{\phi }_{sp}}=\Delta {{\rho }_{f}}/\Delta {{\rho }_{s}}</math>. Therefore

<math>{{\phi }_{f}} = \Large \frac{\phi}{\phi_{sp}} \normalsize . \qquad (22)</math>

When <math>\phi_f</math> is less than 1 the mixture of sediment and water is a suspension in which inter-particle cohesive bonds can form and break, and at the bed surface (<math>\phi_f = 1</math>) the bonds form an incipient solid matrix of permanently interconnected particles. The strength of the matrix increases below the bed surface as <math>\phi_f</math> increases above 1. In the bed, <math>\phi_f</math> is greater than 1 because <math>\phi</math> is larger than <math>\phi_{sp}</math> provided <math>\Delta \rho_f </math> is conveniently assumed to remain unchanged from its value in the suspension. This notional extension of the suspended floc volume "fraction" in the bed permits a continuous representation of sediment concentration across the bed surface. As consolidation proceeds, the sediment skeleton progressively supports a greater proportion of the overburden stress <math>\sigma</math>. Excess pore pressure dissipates and effective normal stress <math>\sigma_v</math> increases, leading to greater sediment strength and reduced water content. As <math>\sigma ={{\sigma }_{v}}+{{\sigma }_{u}}</math>, the pore water pressure <math>\sigma_u</math> decreases as<math>\sigma_v</math> increases with <math>{{\phi }_{f}}</math>.

[[Image:MehtaFig7.jpg|thumb|500px|right| Figure 7. Yield stress variation with floc volume fraction for the Gironde sediment (data from Galichon et al. <ref name=Ga> Galichon, P., Feral, A., Granboulan, F., Viguier, F. (1990). Variations in rheological properties of muds in the Gironde estuary, Proceedings of the International Conference on Coastal Engineering, ASCE, New York, 2936-2949.</ref>).]]

Fluid mud (''FM'') occurs between <math>\phi_f = 1</math> and <math>\phi_{fh}</math>; the latter quantity representing the onset of hindered settling at the lutocline. It may have a value of about 0.03. Fluid mud is a highly concentrated suspension of fine sediment that exhibits fluid-like or viscoplastic behavior. It can develop through the accumulation of settling particles, remobilization of soft sediment beds or advection from other locations. Depending on its concentration, rheological properties and hydrodynamic conditions, fluid mud may flow, consolidate or be entrained into the overlying water. If energy supply is reduced, due to hindered settling the thickness of ''FM'' decreases and its density increases. Close to the bottom of ''FM'', mud that becomes denser than <math>\phi_f</math>= 1 changes into a bed. If the energy supply increases ''FM'' dilates as water is entrained into mud. The density of the upper part of ''FM'' decreases below <math>\phi_{fh}</math>and becomes a dilute suspension (''FL''). These processes can make the thickness of ''FM'' more or less self-limiting.

The floc layer (''FL'') is not subject to hindered settling. Above it there may be a very dilute "residual" suspension (''SF'') containing small flocs and colloids that do not readily deposit. When the flow is not too agitated, in sedimentation calculations the measured mean concentration of ''SF'' is often subtracted from all concentration measurements as a “wash load” value which practically does not participate in sedimentation. At the bed surface, with typical values of <math>\rho_s = 2,650 \;</math> kg m<sup>-3</sup>, <math>\rho_w = 1,000 \;,</math> kg m<sup>-3</sup> and floc density <math>\rho_f = 1,100 \;</math> kg m<sup>-3</sup>, <math>\; \phi_{sp}</math> would be about 0.06. Below surface the bed consists of two layers. The upper layer - stratified bed (''SB''), in which <math>\phi_f</math> (> 1) typically increases with depth due to consolidation, may be no more than about 0.3 m in thickness. The lower layer - uniform bed (''UB''), has a maximum floc volume "fraction" <math>\phi_{fm}</math>. Its value may be as high as 4 (or higher if the bed is over-consolidated).

In ''FM'' the sediment becomes increasingly viscoplastic with depth as the yield stress <math>\tau_y</math> increases with <math>\phi_f</math>. Empirically the two variables can be related by the power law

<math>{{\tau }_{y}}=A\phi _{f}^{p}. \qquad (23)</math>

This relationship is illustrated by data from the Gironde Estuary (France) in Fig. 7. Observe that <math>A = 14.5</math> remains unchanged but the exponent <math>p</math> increases from <math>2.48</math> in fluid mud to <math>4.44</math> in the bed. This increase implies that <math>\tau_y</math> is more significantly dependent on <math>\phi_f</math> in the bed than in fluid mud because inter-particle bonding is stronger in the bed. The lowest recorded yield stress of 1.61 Pa represents the limiting sensitivity of the vane viscometer deployed ''in situ'' for measurement (Galichon et al. <ref name=Ga></ref>).
A more detailed treatment is given in the article [[Fluid mud]].

==Transport of Cohesionless Particles==

In a given volume of flowing water, an ensemble of cohesionless particles: (a) may be carried in suspension through the upstream flow cross-section and out through the downstream cross-section without depositing on the bed or acquiring additional particles eroded from the bed along the reach, (b) may deposit over the reach, thus depleting water of particles leaving the volume, (c) may increase in concentration due to arrival of particles eroded from the bed, or (d) may hop along by sequential deposition and erosion (Fig. 8).

[[Image:MehtaFig8.jpg|thumb|500px|right| Figure 8. Schematic of transport of cohesionless bed material in turbulent flow along a channel reach. Layer thicknesses are not in scale (relative to each other).]]

Condition (a) represents the transport of wash load in which particles in suspension and in the bed are physically apart with no exchange at the bed surface between the two populations (which therefore can remain quite different). Conditions (b), (c) and (d) represent bed material load defined by exchange at the bed surface. Regarding condition (d), which is a general case inclusive of (b) and (c), in steady (turbulent) flow the number fluxes of depositing and eroding particles are equal at sedimentary equilibrium. The resulting advective mass sediment flux (dry mass per unit flow cross-section per unit time) is conventionally divided into bed load (near-bed flux) and suspended load (suspension flux).

A key feature in the equilibrium transport of particles is that erosion and deposition at the bed are governed by the so-called critical shear stress, which is a function of size (Julien 2010<ref name=J></ref>). The initiation of motion of cohesionless bed particles is commonly characterized by a critical bed shear stress, which depends on particle size, density and bed configuration. Sediment deposition and entrainment are stochastic processes that can occur simultaneously. Their relative rates determine whether the bed experiences net erosion or deposition. Net erosion occurs when the flow shear stress at the bed is "just" greater than the critical shear stress because the shear-induced hydrodynamic lift is greater than the buoyant weight of the particle. Under the opposite condition net deposition occurs. In a flow characterized by turbulent fluctuations in shear stress both (erosion and deposition) conditions occur over the bed and result in simultaneous erosion and deposition. This also applies to multi-size class beds over which each class responds to turbulent flow according to its transport regime. In the theory of Einstein<ref name=Ein> Einstein, H.A. (1950). The bed-load function for sediment transportation in open channel flows, Technical Bulletin No. 1026, U. S. Department of Agriculture.</ref>the bed load layer is just a few grain diameters in thickness and within it erosion and deposition are governed by the stochastic properties of boundary layer turbulence (as well as grain properties). In shallow estuaries with depths no more than perhaps 2-3 m, an empirical estimate of the thickness can be about 5% of the water depth. This requires that the near-bed flux be measured in situ at that depth for purposes of bed load estimation. More realistically, for convenience of measurement the thickness of the bed load layer in any estuary may be assumed to be, say, 0.05 or 0.1 m. Precise transport definitions and bed load formulas are found in van Rijn (1984a)<ref name=Rijn84a> van Rijn, L.C. (1984a). Sediment transport, Part I: bed load transport, Journal of Hydraulic Engineering, 110(10), 1431-1455.</ref>.

When the current velocity <math>u</math> peaks at about 1 ms<sup>-1</sup> or higher, the majority of mass flux tends to be as suspended load, which is commonly calculated using the well-known sedimentary equilibrium-based formula of Rouse (see van Rijn<ref name=Rijn84b> van Rijn, L.C. (1984b). Sediment transport, Part II: suspended load transport, Journal of Hydraulic Engineering, 110(11), 1613-1641.</ref>). When the ratio of particle buoyant weight to flow inertia represented by <math>w_{s}/{\kappa} u*</math> is low the suspension is nearly uniform, and as the ratio increases the suspension becomes increasingly “bottom-weighted”. The Rouse formula requires that the suspended sediment concentration be measured at the bottom of the suspended load layer, which can be conveniently taken as the top of the bed load layer. Suspended load is usually the dominant mode of transport for instance at sandy estuarine mouths where strong flood and ebb flows occur. In this case the Einstein-Brown formula (Brown<ref name=B> Brown, C.B. (1950). Sediment transportation, In: Engineering Hydraulics, Chapter 12, H. Rouse, ed., Wiley.</ref>) provides a simple method to roughly estimate the total load by assuming that bed load is minor (Powell et al.<ref name=Po> Powell, M.A., Thieke, R.J., Mehta, A.J. (2006). Morphodynamic relationships for ebb and flood delta volumes at Florida’s tidal entrances. Ocean Dynamics, 56, 295-307.</ref>). The total mass of sediment per unit time per unit width of the estuary channel is obtained from

<math>{{g}_{s}}\ \ =\ \ \Large \frac{0.078{{\rho }_{s}}{{w}_{s}}{{f}^{3}}}{{{g}^{3}}{{\left( \frac{\rho_s}{\rho_w} -1 \right)}^{3}}d_{p}^{2}} \normalsize {{u}^{6}} , \qquad (24)</math>

where <math>f</math> is the Darcy-Weisbach bed friction factor. As an illustration consider a 200 m wide channel with <math>u = 1 \;</math> m s<sup>-1</sup>,<math> \; \rho_s = 2,650 \;</math> kg m<sup>-3</sup>,<math> \; \rho_w = 1,015 \;</math> kg m<sup>-3</sup>,<math> \; f = 0.030, \; d_p = 0.4 \;</math> mm, <math>\; w_s = 60 \;</math> mm s<sup>-1</sup>, which yields <math>g_s = 0.53 \;</math> kg m<sup>-1</sup> s<sup>-1</sup>. Therefore, over the width of the channel the load will be <math>106 \;</math> kg s<sup>-1</sup>.

==Cohesive Sediment==

===Floc deposition===

[[Image:MehtaFig9.jpg|thumb|400px|right| Figure 9. Deposition flux of flocculated sediment from the San Francisco Bay tested in a flume (modified from Mehta et al. <ref name=M14></ref>).]]

When sinking flocs reach the bottom, it is often assumed that settling on the sediment bed will only occur if the bed shear stress <math>\tau_b \approx \rho u_*^2</math> is smaller than a critical shear stress for deposition <math>\tau_d</math>. With this assumption, the volume deposition flux can be written

<math>F_s = w_s \phi \Big( 1 - \Large\frac{\tau_b }{\tau_d}\normalsize \Big) . \qquad (25)</math>

The critical deposition shear stress <math>\tau_d</math> is an empirical parameter in this formulation rather than a universal physical threshold. An alternative approach is to calculate deposition from the settling flux at the bed and erosion from an independent erosion law. In this approach, deposition and erosion can occur simultaneously, and their difference determines the net sediment exchange.

In shallow estuaries in which flocs are conveyed by current over the entire water depth <math>h</math>, starting from Eq. (14) the deposition of flocs in terms of time-rate of decrease of <math>\phi</math> is obtained by mass balance

<math>\Large \frac{d\phi }{dt} \normalsize = -\dfrac{F_s}{h} = - \Large \frac{a(G)}{h} \normalsize \left( 1-\Large \frac{{{\tau }_{b}}} {{{\tau }_{d}}} \normalsize \right){{\phi }^{n+1}} . \qquad (26)</math>

Solving for <math>\phi</math> yields

<math>\phi (t)={{\phi }_{0}} \Big(1+\phi_0^n \Large \frac{n a(G)}{h} \normalsize \left( 1-\Large \frac{{{\tau }_{b}}}{{{\tau }_{d}}} \normalsize \right)t \Big)^{-\Large \frac{1}{n}} \normalsize , \qquad (27)</math>

where <math>\phi_0</math> is the value of <math>\phi</math> at the start of deposition (e.g. at the beginning of a time-step in a numerical model), which causes <math>\phi(t)</math> to decrease (Mehta et al. <ref name=M14></ref>).

In Eq. (14) if aggregation is ignored, i.e. <math>\phi</math> and <math>G</math> do not influence <math>w_s</math>, letting <math>n \rightarrow 0</math> and <math>a</math> constant renders <math>w_s</math> constant. Then Eq. (27) yields

<math>\phi (t)=\phi _0 \; \exp \Big(-\Large \frac{w_s}{h} \normalsize \left( 1-\Large \frac{\tau_b}{\tau_d} \normalsize \right) \, t \Big) \;, \qquad (28)</math>

which is commonly known as the Krone equation.

In Fig. 9, the Krone equation [Eq. (28)] and the generalized Krone equation [Eq. (26)] are plotted along with experimental data from a deposition test run in a flume (<math>h = 0.3 \;</math> m, <math>\; \tau_b = 0.032 \;</math> Pa, <math>\; \tau_d = 0.081 \;</math> Pa) using sediment from Mare Island Strait in San Francisco Bay. The difference between the two curves is due to the inclusion of aggregation in Eq. (26) with <math>\phi_0 = 3.73 \times 10^{-3}, \; a = 4.3, \; n = 0.73</math>, which produced an order of magnitude greater net flux than from Eq. (28), with <math>\phi_0 = 4.11 \times 10^{-4}, \; w_s = 1.44 \times 10^{-6} \;</math> m s<sup>-1</sup>. Thus it is evident that, in general, aggregation must not be ignored when modeling floc deposition.

===Cohesive bed erosion===

There are two principal modes of cohesive bed erosion – surface erosion and mass erosion. In the first mode bed flocs exposed to shear stress <math>\tau_b</math> are eroded when it exceeds the bed floc erosion shear strength <math>\tau_s</math>. This occurs under the soil mechanically drained condition in the top bed floc layer as the time for dissipation of excess pore pressure due to fluctuating turbulent flow tends to be shorter than the characteristic time <math>t_e</math> for the detachment and entrainment of floc. The magnitude of <math>\tau_s</math> is close to cohesion defined by the Mohr-Coulomb criterion (Winterwerp et al. <ref > Winterwerp, J.C., van Kesteren, W.G.M., van Prooijen, B., Jacobs, W. (2012). A conceptual framework for shear-flow induced erosion of soft cohesive sediment beds. Journal of Geophysical Research, C10020, doi:10.1029/2012JC008072.</ref>). Mass erosion occurs when hydrodynamic forces cause mechanical failure of a cohesive sediment bed, resulting in the detachment of coherent portions of sediment. Unlike surface erosion, which involves the gradual removal of particles or aggregates, mass erosion can remove substantial amounts of sediment over a short period. Its occurrence depends on the strength and internal structure of the bed as well as the applied hydrodynamic stresses. For soft cohesive beds the yield stress is a convenient surrogate for this shear strength. Organic-rich fine sediment beds such as those found in lakes are typical candidates for mass erosion (Mehta et al.<ref name=M15> Mehta, A.J., Hwang, K.-N., Khare, Y.P. (2015). Critical shear stress for mass erosion of organic-rich fine sediments, Estuarine, Coastal and Shelf Science, 165, 97-103.</ref>).

[[Image:MehtaFig10.jpg|thumb|500px|right| Figure 10. Erosion flux against bed shear stress. Data are from Lake Apopka and plots of expressions from Table 2 (revised from So et al. <ref name=So> So, S., Khare, Y., Park, K., Mehta, A. (2013). Critical wind and turbidity rise in a shallow Florida lake, WIT Transactions on Ecology and the Environment, 169, doi:10.2495/CP130211.</ref>).]]

Bed strength depends on consolidation history, water content, sediment composition, biological binding and the structure of the sediment matrix. Only a handful of formulas for the surface erosion flux <math>E_s</math> have been developed from the first principles. Partheniades<ref name=P65> Partheniades, E. (1965). Erosion and deposition of cohesive soils, Journal of the Hydraulics Division of ASCE, 91(1), 105-138.</ref> treated <math>\tau_b</math> as the sum of the time-mean value <math>\bar \tau_b</math> and a fluctuating component <math>\tau'_b</math> with (unbounded) normal frequency distribution. Furthermore it was assumed that <math>t_e</math> is independent of <math>\tau_b</math>. This led to an equation with an upper-limit erosion rate that cannot be exceeded at high values of <math>\tau_b</math>. In turn this restriction can result in gross underestimation of <math>E_s</math> at high current velocities. It was pointed out by van Prooijen and Winterwerp<ref name=PW> van Prooijen, B.C., Winterwerp, J.C. (2010). A stochastic formulation for erosion of cohesive sediments. Journal of Geophysical Research, 115, C01005, doi:10.1029/2008JC005189.</ref> that the error can be corrected by recognizing that <math>t_e</math> must decrease as <math>\tau_b</math> increases, and as a separate consideration <math>E_s</math> must vary with the excess bed shear stress <math>\tau_b - \tau_s</math> because in reality <math>\tau_b</math> cannot have an unbounded distribution.

In the resulting Eq. (29), <math>M</math> is an empirical flux constant,

<math>\tau _{s}^{*}=\alpha {{\hat{\tau }}_{s}}-\beta {{\delta }^{2}}, \; {{\hat{\tau }}_{s}}={{\tau }_{s}}/{{\bar{\tau }}_{b}}(1+{{\delta }^{2}}), \; {{\sigma }_{b}}={{[{{\bar{\tau }}_{b}}(1+{{\delta }^{2}})/{{\rho }_{w}}]}^{0.5}}\; </math>

is the standard deviation of bed shear stress based on randomly varying near-bed velocity <math>u_{b}(t)</math> with a mean <math>u_b</math> and <math>\delta = u_b/{\sigma}_u</math>. Best-fit values of the coefficients <math>\alpha</math> and <math>\beta</math> were based on measured (non-normal) distribution of <math>\tau_b</math> due to its dependence on <math>{u_{b}^{2}}</math> (quadratic law). For the plot in Fig. 10, which also includes data from Lake Apopka (Mehta et al. <ref name=M9> Mehta, A.J., Jaeger, J.M., Valle-Levinson, A., Hayter, E.J., Wolanski, E., Manning, A.J. (2009). Resuspension dynamics in Lake Apopka, Florida, Final Report, Submitted to St. Johns River Water Management District, Palatka, FL </ref>), the selected values are <math>\rho_w = 1,000 \;</math> kg m<sup>-3</sup>, <math>\; u_b = 4.09 \times 10^{-2} \;</math> m s<sup>-1</sup>, <math>\; \sigma_u = 4.09 \times 10^{-2} \;</math> m s<sup>-1</sup>, <math> M = 4.79 \times 10^{-3} \;</math> kg N<sup>-1</sup> s<sup>-1</sup>, <math>\; \tau_s = 0.14 \;</math> Pa, <math>\; \alpha = 30, \; \beta = 70.</math>

[[Image:MehtaTable2.jpg|thumb|900px|center| Table 2. Erosion flux equations. The references can be found in the section References]]

Equation (30) is a polynomial approximation of Eq. (29) with sediment dependent coefficients <math>a_1</math> through <math>a_4</math>. However, the severity of approximation makes Eq. (30) entirely empirical. Thus a restriction on use is that other than (measured) <math>\tau_s</math> the coefficients must be obtained by tuning. An advantage is that in some cases it may be sufficient to consider just one term within the brackets, which reduces the expression to a linear, quadratic or third-order polynomial, each with a single free coefficient. Selected values in Fig. 10 are <math>\tau_s = 0.12 \;</math> Pa, <math>a_1 = -1.14, \; a_2 = 10.9, \; a_3 = -5.87, \; a_4 = -1.37</math>.

In Eq. (31) the stochastic basis of Eq. (29) has been extended by treating <math>\tau_s</math> as the sum of a spatial mean value <math>\bar \tau_s</math> and a component <math>\tau'_s</math> varying over the bed surface. The quantities <math>\varphi(\tau_b)</math> and <math>\varphi(\tau_s)</math> are the frequency distributions of <math>\tau_b</math> and <math>\tau_s</math>, respectively, and <math>\phi_E</math> is a characteristic erosion-related volume fraction. The distribution <math>\varphi(\tau_b)</math> is produced using the quadratic law mentioned earlier and Monte Carlo simulation from randomly fluctuating turbulent velocity <math>u</math>. Thus <math>\varphi({\tau_b})</math> does not have a prescribed canonical form (unless one is deduced from experimental data). Due to the absence of adequate data, <math>\varphi(\tau_s)</math> is conveniently taken as normal. The Heaviside function <math>H(\operatorname{\theta})</math> = 0 if <math>\operatorname{\theta}</math> < 0, 1 if <math>\operatorname{\theta}</math> > 0 and 0.5 if <math>\operatorname{\theta}</math> = 0. Parametric values are: <math>\phi_E = 4.06 \times 10^{-4}, \; \rho_s = 1,873 \;</math> kg m<sup>-3</sup>, <math> \bar \tau_s = 0.15 \;</math> Pa. Additionally the standard deviations of bed shear stress <math>\sigma_b</math> (0.035 Pa) and floc shear strength <math>\sigma_s</math> (0.020 Pa) are required (Letter and Mehta<ref name=LM11> Letter, J.V., Jr., Mehta, A.J. (2011). A heuristic examination of cohesive sediment bed exchange in turbulent flows, Coastal Engineering, 58, 779-789.</ref>). A limitation of the method is that there is no closed-form expression for calculating the erosion flux.

Empirical Eq. (32), which is the linear (empirical) form of Eq. (30) with erosion flux constant <math>M'</math>, was originally proposed by Ariathurai <ref name=Ar> Ariathurai, R. (1974). A finite element model for sediment transport in estuaries, PhD Thesis, University of California, Davis.</ref>. The plot is based on <math>M'= 0.09 \;</math> kg N<sup>-1</sup> s<sup>-1</sup><math>, \; \tau_s = 0.10 \;</math> Pa. It shows an abrupt transition at the critical shear stress which is not quite supported by the data indicating a gradual transition.

===Erosion shear strength===

[[Image:MehtaFig11.jpg|thumb|550px|right| Figure 11. Relationship between bed floc erosion shear strength and viscoplastic yield stress.]]

The shear strength <math>\tau_s</math> is determined by a variety of field- and laboratory-based devices. These tests can be both costly and time consuming, and as a result for rough estimation of <math>\tau_s</math> it is convenient to use the following empirical relationship of Migniot<ref name=Mi></ref> relating <math>\tau_s</math> to the yield stress <math>\tau_y</math>, which can be readily measured in a rotary viscometer

<math>{{\tau }_{s}}=\left\{ \begin{align}
& {{\alpha }_{0}}{{\rho }_{w}}\sqrt{{{\tau }_{y}}};\quad {{\tau }_{y}}\le {{\tau }_{y}}_{0} \\
& {{\beta }_{0}}{{\rho }_{w}}{{\tau }_{y}};\quad \quad {{\tau }_{y}}>{{\tau }_{y}}_{0} \\
\end{align} \right. \qquad (33)</math>

Equation (33) in two segments with <math>\tau_{y0} =1.37 \;</math> Pa appears to hold for a wide variety of cohesive sediments as seen by the data sets of Migniot<ref name=Mi></ref> and of Ohtsubo and Muraoka <ref name=OM> Ohtsubo, K., Muraoka, K. (1986). Re-suspension of cohesive sediments by currents. In: Proceedings of the 3rd International Symposium on River Sedimentation, University of Mississippi, Oxford, 1680-1689. </ref> (<math>\alpha_0 = 2.20 \times 10^{-4}, \; \beta_0 = 1.88 \times 10^{-4},</math> <math> \rho_w = 1,000 \;</math> kg m<sup>-3</sup>). In a fractal floc as part of a “bed” subjected to shear in a viscometer, the number of inter-particle bonds at the plane of floc failure (breakup) is by definition independent of bed floc diameter <math>d_f</math> (Kranenburg <ref name=Kra></ref>). In other words, <math>K</math>, the product of <math>\tau_y</math> and the characteristic maximum cross-sectional area <math>\pi d_{f}^{2}/4</math> does not vary with <math>d_f</math>

<math>{{\tau }_{y}}\frac{\pi }{4}d_{f}^{2}=K. \qquad (34)</math>

Using Eq. (11) yields

<math>{{\tau }_{y}}={{K}_{0}}\Delta \rho _{f}^{2/(3-D)};\quad {{K}_{0}}=\Large \frac{4K} {\pi d_{p}^2 \Delta \rho _s^{\frac{2}{(3-D)}}} \normalsize . \qquad (35)</math>

The validity of Eq. (35) was demonstrated by Kranenburg<ref name=Kra></ref> using yield stress data of Krone<ref> Krone, R.B. (1963). A study of rheological properties of estuarial sediments, Technical Bulletin No. 7, Committee on Tidal Hydraulics, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.</ref> for marine and aquatic muds. It was shown that the fractal basis was reasonable; a representative value of <math>D</math> was about 2.2. From Eqs. (11) and (35)

<math>{{\tau }_{y}} = K_0 \Delta {\rho_s}^{2/(3-D)} \left( \Large \frac{d_p}{d_f} \normalsize \right)^2, \qquad (36)</math>

in which <math>K_0</math> is essentially a calibration constant. For given cohesive sediment Eq.(36) indicates a relationship between the floc diameter <math>d_f</math> and <math>\tau_y</math>. It appears that for a wide range of sediments, <math>K_0 = 9.8 \times 10^{-6}, \; \Delta \rho_s = 1,650 \;</math> kg m<sup>-3</sup>, <math>\; D = 2.2, \; d_p = 0.1 \;</math> μm (Mehta and Letter<ref name=ML13> Mehta A.J., Letter, J.V., Jr. (2013). Comments on the transition between cohesive and cohesionless sediment bed exchange, Estuarine, Coastal and Shelf Science, 131, 319-324.</ref>). Note that as Eq. (23) relates <math>\tau_y</math> to the floc volume fraction <math>\phi_f</math>, there is an implied dependence of <math>\phi_f</math> on <math>d_p</math>. However, such a dependence has not been demonstrated for fractal flocs.

===Characteristic shear stresses===

Unlike cohesionless sediment transport in which erosion and deposition are characterized by the critical shear stress for erosion <math>\tau_c</math>, cohesive sediment requires specification of the erosion shear strength <math>\tau_s</math> as well as the critical shear stress for deposition <math>\tau_d</math>. Sediment deposition and erosion are distinct processes that can occur simultaneously. The net exchange between the water column and the bed is determined by the difference between their respective mass fluxes. Floc deposition can occur when its buoyant weight exceeds the hydrodynamic lift force, but erosion requires the lift force to exceed the sum of buoyant weight and cohesion which attaches the floc to the bed. Thus, the lift force needed to erode the floc is greater than that at which deposition can occur and, noting that the bed shear stress is proportional to lift, <math>\tau_s</math> is characteristically larger than <math>\tau_d</math>.

[[Image:MehtaFig12.jpg|thumb|900px|center| Figure 12. Characteristic shear stresses defined by their relationship to floc/particle diameter (revised from Mehta and Letter<ref name=ML13></ref>).]]

In Fig. 12 an effort has been made to represent <math>\tau_s, \; \tau_d</math> and <math>\tau_c</math> in a single plot as functions of floc/particle diameter. For this purpose, in Eq. (33) <math>\tau_y</math> has been replaced by <math>d_f</math> with the help of Eq. (36) (and <math>d_p = 0.1</math> μm). For cohesionless sediment down to 11 μm, which is close to the 10 μm mentioned earlier, <math>\tau_c</math> can be related to particle diameter <math>d_p</math> using the implicit empirical Brownlie<ref> Brownlie, W.R. (1981). Prediction of flow depth and sediment discharge in open channels, PhD Thesis, Caltech, California.</ref> equation in a slightly modified form

<math>{\tau }_{c} = g \Delta \rho _s \left[ \large ( \frac{0.1050}{\operatorname{Re}_{*}^{0.6}} - \frac{0.0142}{\operatorname{Re}_{*}^{1.03}} ) + ( \normalsize 0.770 \large e^{-102.7\operatorname{Re}_*} - \normalsize 0.135 \large e^{-15.95 \operatorname{Re}_*} \normalsize ) + 0.068 \cdot 10^{\Large \frac{-4}{{\operatorname{Re}_*}^{0.6}} \normalsize } \right] {d}_{p}, \qquad (37)</math>

where <math>\operatorname{Re}_{*}={{\rho }_{w}}{{u}_{*}}{{d}_{p}}/\eta </math>.

The deposition stress <math>\tau_d</math> is based on the relationship

<math>{{\tau }_{d}}={{\tau }_{{{d}_{p}}}}\sqrt{d_f / d_p}\qquad (38)</math>

as proposed by Mehta and Letter<ref name=ML13></ref> based on flume data of Mehta and Lott<ref name=ML87> Mehta, A.J., Lott, J.W. (1987). Sorting of fine sediment during deposition. Proceedings of Coastal Sediments’87, ed. Kraus, N. C., ASCE, 348-362.</ref> for kaolinite deposition with <math>\tau_{d_p} = 4.29 \times 10^{-3}</math> and <math>d_p = 0.1</math> μm. The equation line is conveniently selected to intersect the junction of Eqs. (33) and (37), although in reality intersection can vary somewhat from its value at the junction depending on clay mineral composition.

[[Image:MehtaFig13.jpg|thumb|400px|right| Figure 13. Schematic description of bed exchange zones and transition diameter based on Fig.12 (revised from Mehta and Letter<ref name=ML13></ref>).]]

An important feature of Fig. 12 is that the abscissa represents both <math>d_f</math> and <math>d_p</math> depending on the characteristic stress, which makes the entire representation somewhat subjective. The transition diameter <math>d_T</math> (11 μm) and the diameter for Eq. (37) refer to particles, whereas Eq. (33) for diameters larger than <math>d_0 = 1.52 </math> μm relates to <math>d_f</math>. Diameters smaller than <math>d_0</math>, mainly submicron, can be <math>d_p</math> or <math>d_f</math>, however, Eq. (33) in this range as well as Eq. (38) are based on <math>d_f</math>.

The difference between <math>\tau_s</math> and <math>\tau_d</math> at a given diameter notionally begins at <math>d_T</math> and increases with decreasing diameter <math>d_p</math>, i.e. increasing cohesion. Although in reality the difference between these two stresses cannot be nil for flocs of diameter <math>d_f</math> larger than <math>d_p = d_T</math>, it can be expected to decrease rapidly as the flocs become open-structured and lighter with increasing size. One may anticipate the trend in <math>\tau_d</math> to resemble the sketched curve.

Referring to Figs. 13a,b, 13a describes zones of erosion and deposition. Sediment load calculations for cohesionless particles (diameter greater than <math>d_T</math>) encounter <math>\tau_c</math> as the only characteristic shear stress. Conveniently assuming the instantaneous bed shear stress <math>\tau_b</math> as having an unbounded (e.g. normal) distribution, when <math>\tau_b</math> is greater than <math>\tau_c</math> there can be erosion only, and when <math>\tau_b < \tau_c</math> there can be only deposition. Thus, as long as erodible particles are present, over any unit area large enough to represent the bed (Fig. 8), it can either erode or deposit on an instantaneous basis. Therefore, in general there will be simultaneous erosion and deposition along the entire channel reach.

When the sediment is cohesive, simultaneous erosion and deposition will not occur when the floc diameter is smaller than <math>d_T</math> and <math>\tau_b</math> is greater than <math>\tau_d</math> but less than <math>\tau_s</math>. In reality such “blank” periods do not occur because: (1) floc size has a characteristically graded distribution with diameters smaller and larger than <math>d_T</math>, and (2) the diameter can change due to aggregation (Sanford and Halka<ref name=SH> Sanford, L.P., Halka, J.P. (1993). Assessing the paradigm of mutually exclusive erosion and deposition of mud, with examples from upper Chesapeake Bay. Marine Geology, 114(1-2), 35-37</ref>). A simple example of this is given in Fig. 14, which shows a floc settling test conducted in a 4.25 m tall and 0.29 m diameter column containing sediment from the Ems Estuary in the Netherlands. An oscillating grid system inside the column imparted a uniform shear rate of <math>7.3 \;</math> s<sup>-1</sup> during the settling process (van Leussen <ref name=VL></ref>). The initial suspension (<math>\phi = 3.9 \times 10^{-4}</math>) consisted of uniform-size microflocs (<math>d_f = 17 </math> μm).

[[Image:MehtaFig14.jpg|thumb|800px|center| Figure 14. Development of bimodal macrofloc diameter distribution from uniform microflocs (based on Lee et al. <ref name=Lee> Lee, B.J., Toorman, E., Molz, F.J., Wang J. (2011). A two-class population balance equation yielding bimodal flocculation of marine or estuarine sediments, Water Research, 45, 2131-2145.</ref>).]]

As observed, after 180s shear-induced aggregation led to a shift in the initial mass of the microflocs with the production of larger microflocs (92 μm) from the microflocs, and after 1280 s, 200 μm macroflocs were formed with further shift in mass. A numerical model (1D vertical) accounting for aggregation and using multi-class particle population balance was used for simulation purposes (Hsu et al. <ref name=Hsu> Hsu, T.-J., Traykovski, P.A., Kineke, G.C. (2007). On modeling boundary layer and gravity-driven fluid mud transport, Journal of Geophysical Research, 112(C04011), doi:10.1029/2006JC003719.</ref>, Lee et al. <ref name=Lee></ref>). In single size class modeling the best approximation for avoiding the (unreal) blank zone is by selecting <math>\tau_d = 0</math> (Fig. 13b) (Winterwerp and van Kesteren<ref name=WK4></ref>).

===Fluid mud entrainment===

When a layer of fluid mud occurs between the bed and “dilute” suspension (in which, as mentioned, settling is characteristically not in the hindered mode), the transport of flocs can be complicated by simultaneous entrainment and hindered settling of fluid mud as well as its advection. Modeling advection requires consideration of the viscoplastic properties of mud (Whitehouse et al. <ref name=Whi> Whitehouse, R., Soulsby, R., Roberts, W., Mitchener, H. (2000). Dynamics of Estuarine Muds: A Manual for Practical Applications, Thomas Telford.</ref>).

[[Image:MehtaFig15.jpg|thumb|400px|right| Figure 15. Dependence of fluid mud entrainment flux on material density <math>\rho_M</math> (or volume fraction <math>\phi_M</math>).]]

The entrainment flux <math>E_f</math> of fluid mud in inner flow boundary layer thickness of <math>h_b</math> and velocity <math>u_b</math> may be roughly estimated from

<math>{{E}_{f}}={{\rho }_{s}}{{\phi }_{M}}{{u}_{b}}\left( \Large \frac{{{A}_{E}}}{Ri} \normalsize -{{B}_{E}}Ri \right);\quad Ri=\Large \frac{{g}'{{h}_{b}}}{u_{b}^{2}} \normalsize ;</math>

<math>{g}'=g{{\phi }_{M}}\left( \Large \frac{{{\rho }_{s}}}{{{\rho }_{w}}} \normalsize -1 \right), \qquad (39)</math>

where <math>Ri</math> is the bulk Richardson number and <math>\phi_M</math> is the volume fraction of fluid mud (Mehta and Srinivas<ref name=MS> Mehta A.J. and Srinivas R. (1993). Observations on the entrainment of fluid mud in shear flow. In: Nearshore and Estuarine Cohesive Sediment Transport, A.J. Mehta ed., American Geophysical Union, Washington, DC, 224-246.</ref>). The coefficients <math>A_E</math> and <math>B_E</math> depend on the environment, but their starting values could be <math>5 \times 10^{-3}</math> and <math>1 \times 10^{-5}</math>, respectively.

In Fig. 15, <math>E_f</math> is plotted against fluid mud material density <math>\rho_M</math> using parametric values based on Lake Apopka with <math>h_b = 1 \;</math> m, <math>u_b = 0.20 \;</math> m s<sup>-1</sup>, <math>\; \rho_s = 1,873 \;</math> kg m<sup>-3</sup>, <math>\rho_w = 1,000 \;</math> kg m<sup>-3</sup>, <math>\; A_E = 5 \times 10^{-3}, \;B_E = 1 \times 10^{-5}</math>. The material density <math>\rho</math> of fluid mud consisting of organic-rich sediment ranges from <math>1,020\; </math> to <math>1,170 \;</math> kg m<sup>-3</sup> (Mehta et al. <ref name=M15></ref>). As <math>\rho_M</math> increases the buoyant weight of a fluid parcel increases and causes the entrainment flux to decrease rapidly. For the parameter values used in this example, the calculated entrainment flux approaches zero at a fluid mud density <math>\rho_M</math> of approximately <math>1,090 \;</math> kg m<sup>-3</sup>. This threshold is specific to the assumed hydrodynamic conditions and empirical coefficients and should not be interpreted as a general limit.

===Basin sedimentation===

[[Image:MehtaFig16.jpg|thumb|600px|right| Figure 16. Sedimentation in a boat basin: (a) Depths in the basin relative to MSL, (b) simulated sediment influx over 30 days (Mehta 2016 unpublished; courtesy Dr. S. Neelamani, KISR, Kuwait).]]

Coastal fluid mud is a common source of sedimentation in ports and harbors. Small-craft basins with single entrances provide convenient “meso-scale” illustrations of sedimentation in a deposition-dominated prototype environment. The basin in Fig. 16a is in a shallow bay with a semi-diurnal tidal range of about 1.7 m. Outside the basin the sea bed is sandy, and as the concentration (<math>\phi</math> in the range of <math>4 \times 10^{-5} - 1 \times 10^{-4}</math>) of suspended clayey sediment is generally low, fluid mud is not readily formed locally, so its known presence as a layer of about 5 cm thickness is believed to be due to advection from an exogenous alluvial source. Fine-medium sand and mud enter the basin during flood flow but little material leaves during ebb. A 3D hydrodynamic model was used to transport sand (as bed load and suspended load) and clay flocs (as suspended load) entrained from fluid mud. A design sand trap was placed in the entrance channel. The plotted deposition isopleths after a 30-day period of simulation (Fig. 16b) indicate that the trap is successful in capturing most sand but little cohesive material, which has spread into the deeper part of the basin. See also [[Siltation in harbors and fairways]].

==Acknowledgment==

Thanks are due to Prof. Minwoo Son for his comments on an earlier draft. The third author (AM) was partly supported by USGS co-operative agreement with HR Wallingford, and the HR Wallingford project “Fine Scale - Dynamics of Fine-grained Cohesive Sediments at Varying Spatial and Temporal Scales”.

==Related articles==
:[[Dynamics of mud transport]]
:[[Flocculation cohesive sediments]]
:[[Coastal and marine sediments]]
:[[Mud]]
:[[Fluid mud]]
:[[Mud consolidation and desiccation]]
:[[Estuarine turbidity maximum]]
:[[Coastal mud belt]]
:[[Sediment transport formulas for the coastal environment]]
:[[Sand transport]]
:[[Biogeomorphology of coastal systems]]

==References==
<references/>

<div style = "float: center"> <div align="center">
{| style="border:1px solid #abd5f5; background:#f1f5fc; margin:0em 0em 0em 5em;"
|<center>The main authors of this article are [https://marineinfo.org/imis?module=person&persid=33152 Ashish Mehta] , [https://marineinfo.org/imis?module=person&persid=33788 Yogesh Khare] and
[https://marineinfo.org/imis?module=person&persid=24063 Andrew Manning] </center>
|}

[[Category:Physical coastal and marine processes]]
[[Category:Sediment]]

Sand-filled geosystems in coastal engineering

2026-11-10T12:00:50Z

Admin: Text replacement - "http://www.coastalwiki.org/imis/imis.php?module=person&persid=" to "https://marineinfo.org/imis?module=person&persid="

==Abstract==

Sand-filled geosystems can be used in a wide range of coastal engineering applications. This article provides a summary of design rules based on the existing theories as well as recommendations regarding the durability and other properties of the materials used in the manufacturing of the geosystems. It is intended to give coastal managers, designers, contractors, and practitioners in general, insight in the applications and the limitations of sand-filled geosystems in coastal engineering and guide them forward to further reading in case more detail on their design is useful.

==Introduction==

Geosystems are three-dimensional elements manufactured from woven and/or non-woven geotextile fabrics. Even though there are a number of applications with open systems, e.g. the geotextile-wrap around revetment constructed at the Island of Sylt in Germany<ref> Nickels, H.; and Heerten, G. (1996). Building elements made of geosynthetics and sand resist North Sea surf. Proceedings of the First European Geosynthetic Conference (EuroGeo), Maastricht, The Netherlands, October 1996.</ref> , geosystem elements are generally pre-fabricated closed forms/units in four distinct types, bags, mattresses, tubes and containers. In special applications (e.g., dams), outside the scope of the present article, they can be made from water-tight geosynthetics, such as geomembranes and/or special composite systems. They can be filled with sand, gravel or mortar, yet only the use of sand as filling material is considered in this article.

Although the concept of wrapping sand in a geotextile is not innovative – actually it goes back to the 1950’s<ref name="BV8"> Bezuijen, A.; and Vastenburg, E. (2008). Geosystems, possibilities and limitations for applications,Proceedings of EuroGeo4: Fourth European Geosynthetics Conference, Edinburgh, Scotland, United Kingdom.</ref> – it was only in recent decades that attention has turned to the use of these materials on permanent coastal structures. Before they have been mostly applied on temporary and emergency works. Experience with sand-filled geosystems worldwide has shown that they can be used effectively as hidden components (e.g. in the core of a breakwater, groyne or seawall), in coastal areas exposed to low wave energy and/or tidal regime, on projects where there is no risk to life or assets in the event of failure, on projects with regular inspection and maintenance, and in complement to artificial sand nourishments. However, their wider application is still hampered by the lack of readily available knowledge. As a consequence, despite some recognised advantages, the use of sand-filled geosystems as alternative to more conventional materials (e.g., rock or concrete units) is seldom considered.
Exceptions to such lack of knowledge are the books of Pilarczyk<ref name="Pil"> Pilarczyk, K. (2000). Geosynthetics and geosystems in hydraulics and coastal engineering, Rotterdam: A.A.Balkema Publications, 913p, ISBN 90-5809-302-6. </ref>] , which has the most thorough review of the knowledge and experience on geosynthetics and geosystems in coastal engineering from the late nineties of the last century and earlier and is still the reference book on this topic. Other references are
* Koerner<ref name="Koer"> Koerner, Robert M. (2006). Designing with geosynthetics, Xlibris Corp., 524pp, ISBN-13: 978-1462882885. </ref> , which gives a general overview on designing with geosynthetics;
* the practice guideline on the application of geosynthetics in waterfront areas from PIANC<ref> PIANC (2011). The application of geosynthetics in waterfront areas, PIANC Report no. 113.</ref>;
* the translation into English and update of CUR-publication 217 “Ontwerpen met geotextiele zandelementen” by Bezuijen and Vastenburg<ref name="BV13"> Bezuijen, A.; and Vastenburg, E.W., 2013. Geosystems Design Rules and Applications, CRC Press, 145pp, ISBN 978-0-415-62148-9.</ref> , which is currently the most comprehensive manual for designing with sand-filled geosystems;
* the recent past research at the Leichtweiss Institute in Germany (see, e.g., Dissanayake<ref> Dissanayake, D.T. (2013). Experimental and Numerical Modelling of the Hydraulic Stability of Geotextile Sand Containers for Coastal Protection, PhD Thesis: Leichtweiβ Institute for Hydraulic Engineering and Water Resources, Germany.</ref> ; Oumeraci and Recio<ref> Oumeraci, H.; and Recio, J. (2009). Geotextile sand containers for shore protection, Handbook of Coastal and Ocean Engineering, Y.C. Kim (ed.), Singapore: World Scientific Publishing Co. Pte. Ltd., pp. 553-600, ISBN 13-978-981-281-929-1.</ref> ; Recio<ref> Recio, J. (2007). Hydraulic stability of geotextile sand containers for coastal structures - effect of deformations and stability formulae, PhD Thesis: Leichtweiβ Institute for Hydraulic Engineering and Water Resources, Germany.</ref> ; Oumeraci et al.<ref> Oumeraci, H.; Hinz, M.; Bleck, M.; and Kübler, S. (2002). Großmaßstäbliche Untersuchungen zur hydraulischen Stabilität geotextiler Sandcontainer unter Wellenbelastung, Braunschweig, Germany: Leichtweiβ Institute for Hydraulic Engineering and Water Resources, Research Report no. 878, unpublished (in German).</ref> );
* DELTARES in The Netherlands (see, e.g., van Steeg and Vastenburg<ref> van Steeg, P.; and Vastenburg, E. (2010). Large scale physical model tests on the stability of geotextile tubes, DELTARES.</ref> ; and van Steeg and Breteler<ref> van Steeg, P.; and Breteler, K. (2008). Large scale physical model tests on the stability of geocontainers, DELTARES.</ref> );
* University of Porto in Portugal (see, e.g., das Neves et al.<ref name="Nev15"> das Neves, L.; Moreira, A.; Taveira-Pinto, F.; Lopes, M.L.; and Veloso-Gomes, F. (2015). Performance of submerged nearshore sand-filled geosystems for coastal protection. Coastal Engineering 95, 147–159, doi:10.1016/j.coastaleng.2014.10.005.</ref> ; and das Neves<ref name="Nev11"> das Neves, L. (2011). Experimental stability analysis of geotextile encapsulated-sand systems under wave-loading (Ph.D. thesis), University of Porto.</ref> ).

This article is based on the work presented in these references.

==Definitions==

[[Image: LucianaFig.jpg|thumb|400px|right|Figure 1: Geotextile tube application at the beach of Ofir, Esposende, Portugal (photo: Luciana das Neves).]]

For clarity, the following definitions apply in this article:

1. Geotextile tubes are water permeable, sand-tight geotextile (either woven, non-woven, or composite). They are delivered as prefabricated elements to the site, with a number of inlet/outlets for filling. The tube diameters can vary from about 1.6 to 5 m and the length may vary from 25 to 100 m depending on project specifics. When filled with sand or other granular materials the system acquires a pillow form. Geotextile tubes are typically suitable for applications above water and under water to about 6m water depth (i.e. emerged or submerged), and conveniently shall be hydraulically filled.

2. Geotextile containers are large geotextile (typically a woven material) elements containing from about 200 to 600 m3, which are dropped through water from a split barge (installation depth should allow for this). Containers are always installed submerged and can be used as core material of a breakwater that is covered with armour rock, or to raise the bed under the core of a breakwater. The container is unfolded in the split barge (so dimensions of the container have to be considered in relation with the barge dimensions) and the top is sewn in situ once the container is filled. Conveniently they shall be mechanically filled with dry clean sand; this is because it allows for a more even filling and for more air to be enclosed.

3. Geotextile bags are smaller containers manufactured from water permeable, sand-tight geotextile (either woven, non-woven, or composite) of about 0.3 to 10 m3 in volume. Bags can be installed emerged or submerged, possible applications are dune reinforcements, groynes, and offshore scour protections. Typically, they are mechanically filled.

4. Geotextile mattresses are cellular elements manufactured from water permeable, sand-tight geotextile (either woven or composite). Mattresses can be installed as slope or bottom protections. The choice of materials and filling procedure (mechanical or hydraulic filling) depends on project specifics.

==General design aspects==

===Design approach===

As presented by Bezuijen and Vastenburg<ref name="BV13"></ref>, the design of sand-filled geosystems is an iterative process (see Figure 1), where various solutions that comply with functional and performance requirements are sought until a definitive design. Although most of the stages in the design process for sand-filled geosystem are comparable to any other construction material, there are some specifics to the use of such synthetic elements relating to (1) the mechanical (mainly the strength of the fabric and seams), hydraulic and durability properties of the fabric from which the geosystem is manufactured and its connections, (2) the execution methods and the availability of suitable filling material, (3) the impact of deformations on the hydraulic stability of elements and (4) the susceptibility of the materials to damage due to either poor installation, accidental occurrence or vandalism. For these specifics the design process for geosystems shall be made in consultation with manufacturers and installation contractors, with which the designer should closely interact.

[[Image: LucianaFig1.jpg|thumb|1000px|center|Figure 2: Iterative design process for sand-filled geosystems (adapted from Bezuijen and Vastenburg<ref name="BV13"></ref>).]]

===Potential failure mechanisms and safety considerations===

'''Geotextile tubes'''

The following failure mechanisms shall be considered in the design of the geotextile tubes:
* Rupture of the geotextile through excessive pressure during filling;
* Rupture of the geotextile tube through inadequate strength of the seams;
* Instability (rolling) of the geotextile during filling;
* Instability of the geotextile tube under wave loading and/or water currents;
* Loss of stacking stability of the geotextile tube;
* Damage due to construction works;
* Damage to any surface finishing (for example during the installation of the armour layer);
* Sand migration within or from the geotextile tube;
* Draining of the retained material (subsoil/sand behind the geotextile tube);
* Foundation failure and deformation;
* Degradation of the geotextile (creep, UV radiation, abrasion, etc.);
* Accidental occurrence or vandalism.

'''Geotextile containers'''

The following failure mechanisms shall be considered in the design of the geotextile containers:
* Weakening/rupture of the geotextile and/or seams on the geotextile container leaving the split barge;
* Rupture of the geotextile and/or seams upon container impact on the bottom;
* Failure of the geotextile under the action of waves and/or currents;
* Loss of stacking stability of the geotextile containers;
* Damage due to construction works;
* Damage to any surface finishing (for example during the installation of the armour layer);
* Sand migration within or from the geotextile container;
* Foundation failure and deformation;
* Degradation of the geotextile (creep, UV radiation, abrasion, etc.).

'''Geotextile bags'''

The following failure mechanisms shall be considered in the design of the geotextile bags:
* Rupture of the geotextile bags during handling and placement;
* Insufficient seam strength;
* Instability of the geotextile bags under wave loading and/or water currents;
* Sand migration within or from the geotextile bags;
* Foundation failure and deformation;
* Liquefaction of the filling material (no danger if structure slope is milder than 1V:3H);
* Degradation of the geotextile (creep, UV radiation, abrasion, etc.);
* Accidental occurrence or vandalism.

'''Geotextile mattresses'''

The following failure mechanisms shall be considered in the design of the geotextile mattresses:
* Rupture of the geotextile mattresses during handling and placement;
* Rupture of the geotextile mattresses as a result of anchoring (e.g. due to additional loads);
* Insufficient seam strength;
* Instability of the geotextile mattresses under wave loading and/or water currents;
* Failure of the foundation;
* Liquefaction of the subsoil;
* Degradation of the geotextile (creep, UV radiation, abrasion, etc.);
* Accidental occurrence or vandalism.

===Safety factors===

In the design process a safety factor of 1.1 to 1.2 is recommended for geosystems in relation to the design value. Where relevant, additional safety factors (e.g. strength-reduction material factors) based on data provided by the manufacturer or derived from relevant publications (e.g., Koerner<ref name="Koer"></ref>) shall be taken into account. Examples of (commonly used) additional factors are: the strength-reduction material factors of seams (can vary from 30% to over 80% of the strength of the fabric depending on the strength efficiency of the seam, which means factors ranging from 3.33 to less than 1.2); the strength-reduction material factors for creep (a typical value for this factor is 1.4); and the strength-reduction material factors for abrasion (a typical value for this factor is 1.25).
Overall safety factors greater than 5 can be justifiable depending on the execution methods and on aspects related to durability and life-performance.

==Normative references and material aspects==

===Normative references===

Table 1 includes the essential characteristics of geotextiles and geotextile-related products in coastal erosion when used for purposes of filtration, separation, and/or reinforcement, as per EN 13253 "Geotextiles and geotextile-related products – Required characteristics for use in erosion control works". Reference is made to the original documents for further detail on the scope of each of the standards included in Table 1.

[[Image: LucianaTable1.jpg|thumb|900px|center| Table 1: Characteristics of geotextiles and geotextile-related products according to functions and test methods (adapted from ISO 13253).]]

Depending on the function(s) to be fulfilled by a geotextile in a certain application, prescriptions are made which (characteristic) properties of the geotextile (and value, where applicable) shall be included in the technical specifications for a work. These prescriptions will allow for a selection of suitable materials. However, it should be noted that some of the tests in Table 1 (for instance, the puncture and perforation tests) are performed according to a standard method, and therefore do not reflect specific circumstances in reality (for instance, an uncontrolled placement of rock on top of a geotextile fabric). This means that comparing products from different manufacturers with each other is not sufficient to assess performance. Hence, products should be judged on their in-situ based performance in past experiences, where possible.

===Raw materials and processing===

The following raw materials are used to produce the geotextiles from which geosystems are manufactured:
* polyester (PET);
* polypropylene (PP); and
* polyethylene (PE).

The processing technology consists of melting the polymers in granular form followed by extrusion, and eventually spinning. During the melting before extrusion and during further processing, additives can be used as a way to improve the less favourable properties of the basic materials. For instance, polyolefin materials such as polypropylene (PP) and polyethylene (PE) are inherently more sensitive to oxidation than those based on polyethylene terephthalate (PET); however, this behaviour can be improved very effectively by the use of appropriate stabilizing additives. Pigments can also be added. The final processing of the semi-manufactured products (e.g. yarns, filaments, tapes, etc.) will provide the end products (e.g., woven, non-woven or knitted geotextiles) with distinct characteristics.
During the design it should be considered that some geotextile properties such as strength and elongation are derived from the basic materials (i.e., polymers) and from the final processing which yields the shape of the end product (which governs, e.g., permeability and soil tightness), while others such as creep are governed by the raw material only. As such, the use of PET polymers can prove advantageous for its better long-term load carrying capabilities if the geotextile will remain under tension in the structure.

The specific gravity is governed by the raw material. In this regard it is important to consider, most particularly during installation and before when selecting the execution method, that the polyolefin materials (PP and PE) are lighter than water (typically between 0.9 and 0.95) so materials will float, and that PET will sink in water.
For filter or separation functions the geotextile has to be flexible, water-permeable and soil-tight; relevant properties are the aperture size and shape, and the permittivity. Yet, as very often the material has to fulfil several functions, it is possible that a geotextile with a filter function has to absorb tensile stresses. Soil reinforcement requests strong, relatively stiff and preferably water-permeable materials; critical properties are strength and stiffness, although deformations and puncture may have a great impact on the admissible stresses.
Mechanical properties are important in those applications where the geotextile is required to perform a structural role. These properties are also very important when the geotextile is required to survive installation damage and localised stresses.

===Material and geotextile properties===

The material and geotextile properties that need to be defined during the design of a sand-filled geosystem are the gradation of the fill material, type of geotextile fabric from which the geosystem is manufactured and required tensile strength of geotextile and seams. In the following, selected geotextile fabrics are assessed in terms of soil tightness, permeability, and durability.
The geotextile materials used in the manufacturing of geosystems are required to function as a geometrically closed filter (i.e., filter pores are so small that the sand is physically blocked), so to prevent the loss of the fill material over time through the geosystem for all hydraulic gradients while allowing relatively unrestricted water movements through it. The geotextile properties that govern particle retention and water passage capability are the characteristic opening size (or O90) and permeability normal to the plane (or kF), respectively.

The basic principle for determining the required characteristic opening size (O90) of the geotextile is that only a very limited amount of sand may be washed away, otherwise the sand-filled geosystem will deform excessively. It should be noted that when a geosystem is hydraulically filled, some loss of sand during the filling process is normally of no concern. Recommended design criteria for geometrically closed geotextile filters based on fill material properties and hydraulic load are presented in the books of Pilarczyk<ref name="Pil"></ref> and Bezuijen and Vastenburg<ref name="BV13"></ref>.

The permeability of geotextiles in general, and thus also of geotextile-encapsulated sand elements in particular, has to be great enough to prevent the development of excessive pore pressures. A safe assumption is that the permeability of the geotextile must be at least 10 times that of the permeability of the fill material it is filtering.
The geotextile fabric from which the geosystem is manufactured must be robust enough to avoid damage due to high stresses occurring especially during installation, as the filling and installation methods govern the required tensile strength of the geotextile used. In addition, the prescribed geotextile shall have an elongation at rupture that is sufficiently high to avoid damage due to high localised stresses. Depending on the application and execution method to determine the required tensile strength and strain of the geotextile, the raw material and its manufacturing process shall also be considered. For instance, woven geotextiles generally have a relatively high tensile strength and a low maximum strain, while nonwoven geotextiles have a relatively low tensile strength and a high maximum strain. A greater tensile stiffness can be an advantage if maintenance of shape is important, as a stiffer material will not deform as readily.

The strength efficiency of the seams made in the factory is normally a differentiating aspect between geosystems from different manufacturers. It should be noted that a very high reduction percentage in strength (or a very low strength efficiency of the seams) is always a waste in material, as the maximum allowable tensile load in the geosystem will be equal to the maximum tensile strength of the seam and not of the geotextile. For seams made on-site, by a hand sewing machine, lower strengths are normally obtained; therefore, they should be kept to a minimum.

===Durability and life-performance===

Under certain circumstances (e.g., UV-load, hydrolysis, and chemical and/or biological attack), and in the course of time (e.g., due to mechanical damage, fatigue, or creep), the properties of geotextiles can change unfavourably. Indeed much of the uncertainty with respect to geotextiles in civil engineering in general, and in coastal engineering in particular, is related to durability and life-time performance. It is a well-known fact that geotextile fabrics are very susceptible to weathering and must be protected against UV-light. There is a real concern about geotextiles, which links to their fragility against mechanical impact and vandalism.

The decay in resistance due to mechanical damage, weathering (most especially, raised temperature and ultraviolet radiation), chemical degradation, and biological degradation may result in the loss of performance, as a consequence of a loss in strength and in functioning. Differences between geotextile fabrics are very often related to the durability properties of the materials. However, because of the fact that some of the test results cannot be interpreted as a guarantee under normal conditions but rather a tool for selecting a product suitable for the anticipated working life, it is quintessential to judge products based on their performance in-situ.

The extent to which the material loses performance determines durability, which is also influenced by degradation processes during handling and in-service. The term durability is also applied to refer to the capability of the project to continue functioning at an acceptable level even after the construction material has begun to degrade.
During application there is a great probability of mechanical damage. Also, storage and transport require special attention. Moreover, depending on the location and accessibility to the geotextiles, there is a risk of vandalism. All such factors may lead to a reduction in tensile strength, leakage, tearing, crack formation, plastic deformation and differential stretching. These factors are relevant because of the additional stresses or component failures they may induce and/or because of their effect in losing functionality.

Environmental conditions relevant to coastal engineering applications are the geotextiles’ exposure to sunlight (duration and intensity) both in-service and at installation.
Raised temperature and ultraviolet radiation may have a negative effect on geotextiles because such ageing agents stimulate oxidation by which the molecular chains are cut off. Once this process starts, the molecular chains of the geotextile degrade continuously and the original molecular changes. Typically, when the geotextile is exposed to raised temperature and ultraviolet radiation for long time it becomes brittle and loses mechanical resistance. To reduce sensitivity to ageing, additives (e.g., anti-oxidising agents and UV-stabilisers) can be used as a way to improve the less favourable properties of the basic materials. For instance, carbon black is indispensable for extending the life-time expectancy of geotextile materials.

Conveniently, according to the life-time expectancy and the basic material, the chemical resistance (ISO 12960; ISO 13438; and ISO 12447) and microbiological resistance (ISO 12225) should be tested. For instance, some geosynthetics like nylon (polyamide) and, to a lesser extent, polyester are sensitive to hydrolysis under wet conditions (i.e., reaction to water). Moreover, reinforcing materials made of polyester are strongly attacked under high-alkaline conditions, whereas polypropylene can be attacked by some fungi.

Appendix B to standard ISO 13253 presents generic aspects of durability against harmful effects. It provides guidance on maximum exposure times according to the application and the residual resistance after accelerated-ageing test (ISO 12224), and establishes thresholds of resistance in regard to the raw material.

Finally, one aspect that is not often seen in many publications (although mentioned in standard ISO 13253) but should be carefully considered, is the use of recycled polymers in the fabrication of geotextiles, as it can significantly affect its durability and life-performance.

==Hydraulic design criteria for sand-filled geosystems==

===Stability under wave loading===

Several research results suggest that the hydraulic stability of sand-filled geosystems can be checked by means of the following equation:

<math>\large\frac{H_S}{\Delta_t D_k}\normalsize \leq N_S</math> ,

where:

<math>N_S</math> is the stability parameter, a number typically ranging between 0.5 and 3;

<math>H_S</math> is the significant wave-height [m];

<math>D_k</math> is the effective thickness of the geosystem element [m], which depends on the dimensions of the
geosystem and how it is placed with respect to the incident wave direction.

<math>\Delta_t</math> is the relative density of the structural elements, which can be calculated from

<math>\Delta_t = (1-n) (\rho_s - \rho_w)/\rho_w</math> , where <math>\rho_s</math> is the density of the sediment fill [kg/m3], <math>\rho_w</math> is the water density [kg/m3] , <math>n</math> is the porosity of the geosystem fill material.

The stability parameter <math>N_S</math> is expected to depend on an empirical coefficient, which accounts for several factors including the position of the elements with relation to still water level, structure slope, friction, degree of filling, shape and deformation of the elements, and on the breaker parameter, thus accounting for the incident wave period.
Based on existing research, Bezuijen and Vastenburg<ref name="BV13"></ref> present the stability parameters that can be used for the preliminary design of geotextile tubes, containers, bags and mattresses. With respect to geotextile mattresses their use is not recommended where the significant wave height is greater than 1.0 m.

===Stability under water currents===

Little information is available on the stability of the geosystems under overtopping currents. The equilibrium of forces on a single element suggests the following theoretical stability requirement:

<math>\large\frac{u_{cr}}{\sqrt{g \Delta_t D_k}}\normalsize \leq N_S</math> ,

where:

<math>N_{S}</math> is the stability parameter, typically ranging between 0.5 and 1.8 (0.5 to 1.0 are recommended values for preliminary design);

<math>u_{cr}</math> is the critical flow velocity [m/s];

<math>g</math> is the acceleration due to gravity.

To determine the stability of geotextile bags and mattresses when subject to longitudinal current flows (current flow parallel to the structure), use can be made of the relation based on a fully protected foundation of sand (see, e.g., Pilarczyk<ref name="Pil"></ref>):

<math>\Delta_t D_k \geq 0.035 \large\frac{\Phi K_T K_h u_{cr}^2}{2 g \Psi K_s}\normalsize </math> ,

where:

<math>\Phi</math> is a stability parameter, with values of approximately 1.0 for a continuous top layer and 1.5 for edges;

<math>\Psi</math> is the Shields parameter, <math>\Psi = \large\frac{\tau}{g D_k (\rho_s-\rho_w)} \normalsize </math> , where <math>\tau</math> is the bed shear stress;

<math>K_T</math> is the turbulence factor, varying from 1.0 (for “normal” turbulence, as in rivers) to 2.0 (for strong turbulence) and higher (typically 3-4 for turbulence produced by propeller jets and other jets);

<math>K_h</math> is the depth factor, used for translation of the depth average flow velocity into a flow velocity at any depth (<math>h</math>) along the structure. For a fully developed current profile

<math>K_h=2/(log(12h/k_r))^2</math> , where <math>k_{r}</math> is the equivalent roughness according to Nikuradse (assumed equal to <math>D_{k}</math>) and <math>h</math> the flow depth;

for an undeveloped current profile <math> K_{h}=(h/k_{r})^{{-0.2}}</math> and for a very rough current <math>K_h \approx 1 </math> ;

<math>Ks</math> is the slope factor, which is a function of the angle of shearing resistance between the geotextile element and the subsoil (<math>\delta</math>) and the slope angle of the structure (<math>\alpha</math>):

<math>K_s = \sqrt{1-\large\frac{\sin^2 \alpha}{\sin^2 \delta}\normalsize }</math>

For geotextile bags, internal sand movements are expected to occur under flow velocities higher than 1.5 m/s. When velocities are higher than 2.5 m/s bags, become unstable irrespective of size even when placed on slopes as low as 1V:8H.

===Scour development around sand-filled geosystems===

There is very little information on scour development around sand filled geosystems, with the exception of research results based on a series of laboratory measurements of the hydrodynamic and morphodynamic change produced in the vicinity of sand-filled geosystem structures under wave loading at UPorto in Portugal (see, e.g., das Neves et al.<ref name="Nev15"></ref>; and das Neves<ref name="Nev11"></ref>).These research results indicate that:
# Scour development is likely dominated by mechanisms of wave reflection off the structure and wave downrush flow on the exposed slope. The geometric characteristics of the structures (e.g., shape of elements, and porosity) also seem to influence scour development namely due to their effect on those two aspects (i.e., wave reflection, and downrush);
# The comparison of the measured scour depth to the scour depth calculated from predictors has shown that these predictors completely underestimated scour for structures placed landward of the shoreline and for structures exposed to wave breaking of increased intensity due to shoreline retreat. It further showed, that scour depth tends to be less than the incident unbroken wave-height.

==Final remarks==

In this article we have considered only the hydraulic design of geosystem elements and not the geotechnical stability of the full structure. Some stability aspects, internal sand movement and liquefaction, are mentioned below. The reader may consult Bezuijen and Vastenburg<ref name="BV8"></ref> and references cited therein for details on the geotechnical design of sand-filled geosystems.
The stability of a mound (or stack) structure of geosystem elements is dependent on the following potential failure mechanisms:
* stability of the mound under wave loading;
* shear failure of the subsoil; and
* liquefaction of the subsoil.
If the structure is formed as a mound (or stack), pressure differences may occur between the water pressure within the mound (or stack) and the external water pressure. This may cause shearing failures in part of the mound (or stack) and thus pose a threat to stability. There is generally little information available on this, with the exceptions of some work done in Leichtweiss Institute in Germany and DELTARES in The Netherlands.

Excessive deformation due to internal sand movement inside elements may also cause the structure or the elements to become unstable. Excessive deformation depends on hydraulic load and degree of filling, but there is generally little information available on this with the exceptions of some work done in Leichtweiss Institute in Germany and DELTARES in The Netherlands.

Liquefaction refers to the loss of shear resistance in saturated, cohesionless soils during dynamic loading or during earthquakes. Liquefaction may also occur in loose, fine marine soils under wave-loading. With regard to the latter occurrence for structures with reasonably well-compacted sandy subsoil, there is no danger of liquefaction if the slope is less than or equal to 1V:3H, according to Bezuijen and Vastenburg<ref name="BV8"></ref>.

Once the dimensioning of the sand-filled geosystems is completed, the geometric design shall be reviewed and the material and geotextile properties defined, from which a geotextile material can be selected and a definitive design determined.

==Related articles==
:[[Artificial reefs]]
:[[Stability of rubble mound breakwaters and shore revetments]]

==references==
<references/>

<div style = "float: center"> <div align="center">
{| style="border:1px solid #abd5f5; background:#f1f5fc; margin:0em 0em 0em 5em;"
|<center>The main authors of this article are [https://marineinfo.org/imis?module=person&persid=11186 Luciana Das Neves] and [https://marineinfo.org/imis?module=person&persid=11185 Francisco Taveira Pinto] </center>
|}

[[Category:Coastal protection]]
[[Category:Hard structures]]
[[Category:Soft coastal interventions]]

Policy instruments for integrated coastal zone management

2026-11-10T12:00:50Z

Admin: Text replacement - "http://www.coastalwiki.org/imis/imis.php?module=person&persid=" to "https://marineinfo.org/imis?module=person&persid="

== Summary ==

This article presents different policy tools for use in environmental policy more specific in coastal zone management (CZM). The Policy tools are structured from a macro level (societal), but are also seen from a system perspective. In this perspective society is understood as a set of social systems that relates to their environment through a set of codes, symbols and tools. The various types of instruments or measures belong to a social system cultural, legal or economic. The strategies’ starting point is that the political institutions and their actors– i.e. politicians, technocrats and other managers need be aware of possibilities and limitations to governing coastal zones’ complexity. Most of the policy strategies involve use of two or more of these instruments working together; in other words, they are complementary. The article also link the different instruments to institutional levels – showing on what level they are most common in use, whether it’s on the local, regional, national or international level.

== Introduction ==
In the SPICOSA project one important approach is based from the fact that coastal systems are under increasing human and environmental pressures. A consequence of this is the recognition that we need more new and innovative efforts to manage the coastal zones as integrated functional systems. One solution is to improve the way research, decision making and management can be linked together in the governance of coastal zones. One way to systematically do this is to use the SPICOSA’s System Approach Framework to model and predict inputs and outcomes of different kinds of policy instruments.
On the other hand, in social science there are different theories and perspectives to analyze and understand society, social action and government. One of them is a system theory that focuses on major social systems in a macro perspective. Society is here to be seen as a social system including various functional systems (eg. the economic system, legal system, cultural system, and others)(Luhmann 1989)<ref>Niklas Luhmann: Ecological communication, Cambridge: Polity Press, 1989</ref>.
Society is linked to the surrounding ecological systems by individuals and social systems. We deal with nature and nature given life (ecology) through cultural, economical and other activities. This model tries to link ecosystems and social systems.
Each government or management at any level of society has to rely on these systems to govern or manage a limited field of policy action. The economic system, the legal system and the social or cultural system can therefore bee seen as set of instruments in management of a policy field or area- here the coastal ecosystem. In the integration of science and policy in coastal zone assessment this perspective can be useful. The goal is to help any manager to understand what type of legislation tool or instrument is adequate to a sustainable management of the coastal zone.

Integrated coastal zone management is, from a manager’s point of view, a set of tools in solving challenges and problems in the coastal zone:

We can identify a handful of different types of management or policy tools:
* deliberative processes,
* legislative controls,
* planning,
* economic instruments (taxes and subsidies),
* informative measures and at last,
* technology to help or solve social or environmental problems.

These tools can be seen as alternatives or complementary strategies. Important to this is the integrated perspective; every tool must be seen at a part in a holistic approach.

The SPICOSA project’s [http://www.coastal-saf.eu/index.shtml System Approach Framework (SAF)] deals with the identification of one or more environmental problems in the coastal zone, then make a model for dealing with this problem and predict the outcome. The SAF is about designing of a conceptual model taking account of social and economic factors as well as the ecosystem.
This article is a broad presentation of the policy instruments known available applicable as alternative strategy both in the SAF context and in addition to social system approach.

== Policy instruments in coastal zone management ==
Environmental policy instruments include official restrictions and positive incentives designed to control activities that may be harmful to the environment or promote the opposite. We can divide between ‘hard’ and ‘soft’ policy instrument.

In environmental policy '''soft''' instruments will implement typical voluntary, non-binding recommendations and guidelines. Soft policy is relatively new in environmental policy and opens for less authoritative than traditional hard policy instruments (Hertin et al., 2004<ref name=H>Hertin, J., Berkhout, F., Wagner, M. and Tyteca, D. 2004. "Are 'soft' policy instruments effective? The link between environmental management systems and the environmental performance of companies," SPRU Working Paper Series 124, SPRU - Science Policy Research Unit, University of Sussex Business School [http://ideas.repec.org/p/sru/ssewps/124.html]</ref>).
'''Hard''' policy instruments will on the opposite of this be hierarchical regulations, forcing legislations and taxes. These policies can be seen as the ‘command and control’ approach<ref name=H/>.
Environmental policy went through radical changes in the 1980s, when there was a shift away from dealing with narrower problem areas towards broader and more integrated assessments of environmental issues. Environmental policies have subsequently included more preventive measures and controls imposed on potentially harmful activities, rather than corrective measures to repair existing damage. At the same time we have seen a shift to more soft policies and more decentralised approaches<ref name=J>Jordan, A. Wurzel, R., Zito, A. and L. Brückner (2002) The Innovation and Diffusion of ‘New’ Environmental Policy Instruments (NEPIs) in the European Union and Its Member States. In: Biermann, & at (eds.) Global Environmental Change and the Nation State. Potsdam: Potsdam Institute for Climate Impact Research. pp 151-161</ref><ref name=H/>. New environmental policy also includes market-based instruments, such as eco-labels, eco-taxes and tradable permits<ref name=J/>.

In the framework of system approach we have classified policy instruments in coastal zone management into social and informative measures, legislative controls, economic instruments, and technology based initiatives. This kind of classification derives from the idea that policy can influence the system response to improve sustainability in the coastal zones. This is an approach that can be effective to diagnose a problem and set in relevant tool to deal with these problems, weather they are of a natural or a societal kind. It can also be helpful to foresee how different kind of tools can meet different kinds of challenges.

== Social and informative measures ==

'''Deliberative processes, participation and governance'''
The challenge in an integrated coastal zone management (ICZM) is that it does not only involve the area where the landlife meets the sealife, but it also involves humans and human activities. In most ICZM approaches is the idea that the people affected, the stakeholders, should be involved in the resolution of conflicts through a structured, organized process. Exclusion of population groups from decisions, and especially those who face their consequences, leads to conflicts further down the implementation process. In the System approach framework, one have tried to implement the social factor in an integrated CZM. The main focus in this article is however the alternative '''policy instruments''' - and the system approach framework (SAF) can in this part be relevant as a '''supplement''' for the integration of science in policy. Therefore participation and deliberation is part of the policy-making - not a (direct) part of the SAF.

A structured deliberative process can ease these tensions by striving for consensual decisions at an early stage. Deliberation, in that case, is the process by which views are tested and arguments are put forward and countered in discussion and debate. Deliberation processes, participation and governance have therefore both instrumental and a procedural grounding. In short terms the idea is that participation increases the effectiveness and implementation of a political decision. This is very important also in a system approach, but it can be a huge challenge to estimate causality. Effects of deliberation can be the opposite of what was expected.
Deliberative processes are “thinking processes” or communication for raising and collectively considering issues. It refers to different kinds of decision-making. It involves the gathering of information and knowledge from a variety of sources, including consultation with actor and stakeholder inside and outside an organisation or institution.

In the deliberative phase, the myriad of data comes together and is synthesized in a comprehensive plan, or systems model capable of generating various scenarios in an output stag. In the deliberative process, many types of data and knowledge are integrated throughout the process. The idea is to map problems, competing interests and value preferences, not only expert knowledge, but also lay knowledge (See i.e. [http://spicosa-inline.databases.eucc-d.de/files/documents/00000844_D1_6_Methodology_Policy_Issue_Stakeholder_Mapping_with_Example_WP1_v0.pdf Vanderlinden 2009]).

In coastal zone policy and environmental policy deliberation is closely related to the idea of sustainable development. This is grounded in both the idea that sustainability also involves people that live of and close to resources and that traditional and local knowledge is necessary to find sustainable policy. Since the publication of the [http://www.un-documents.net/wced-ocf.htm Brundtland Report] in 1987, the notion of sustainable development has come to guide the pursuit of both public and private environmental reforms and to facilitate communication among different actors and [[stakeholder]]s.
Deliberation can involve various combinations of scientific and technical specialists, public officials, and interested and affected parties. Deliberative processes recognize that environmental plans cannot be pursued without regard to money and political power struggles, including citizens demanding their right to a good environment. The idea of deliberation is ancient, but has among others been enhanced and related to [[http://en.wikipedia.org/wiki/Communicative_rationality communicative rationality] by sociologists like Jürgen Habermas<ref>Habermas Jürgen (1984): The Theory of Communicative Action Boston: Beacon Press</ref>.Although Habermas makes a strong point that consensus is the ultimate end of deliberation and discourse, one can also argue that compromises is an acceptable goal.

The notion of “governance” refers to consistent management, cohesive policies, processes and decision-rights for a given area of responsibility (Wikipedia: [http://en.wikipedia.org/wiki/Governance Governance]) According to the [http://en.wikipedia.org/wiki/United_Nations_Development_Programme United Nations Development Program’s], “governance” has been defined as “The rules of the political system to solve conflicts between actors and adopt decision (legality)”. It has also been used to describe the “proper functioning of institutions and their acceptance by the public” (legitimacy). And it has been used to invoke the efficacy of government and the achievement of consensus by democratic means (participation) UNPD[http://www.undp.org/]. In all definitions Governance involves participation.

===Informative measures===

Informative measures are important in problem definitions and policymaking. It is often difficult or even impossible to trace the original causes of environmental problems. It is therefore vital that the authorities also use “soft” policy instruments to improve our understanding and awareness of these issues. To get public support in a particular policy issue, informative measures is seen as softer that for example legislation which are more forcing. Economic and legal measures in order to be effective must often need public support and legitimacy. Consciousness and awareness of environmental issues are based on new information. This can be done through attitude campaign, education and special training. Other informative measures such as environmental labelling schemes attempt to influence consumption patterns by encouraging consumers to use products and services that are less harmful to the environment. In a system approach framework informative measure can be both as a part of the design and result, rather than a component in the system approach.
Attitude campaigns have been used in various environmental campaign, and can be useful when lack of information and knowledge is the main problem.
Informative measures can be important also as a tool when new technology or new laws are implemented. The need of learning for all implicated parties in a coastal zone area is often underestimated. When a new environmental problem is defined, the need of learning for good solutions is often two-ways: top-down and bottom-up.

Information is the softest and the “easiest” instrument perhaps of all. To inform about institutional changes (like new laws and regulations) or to inform in order to change awareness on an environmental issue or like this article is possible for any institutional level. However, strategies for information ought to be carefully planned so its message reaches out.

==Planning instruments ==
The role of the planning arrangement is to settle development requirements with the aim to protect conserve or improve a field or a policy area. In coastal zone management the policy area can be the sites, environmental quality, habitats and recreational opportunities of the coast. This can be achieved through development and space plans, and planning decision processes. This again is an instrument for implementing policies for the conservation and improvement of the coastal environment and resources.
Planning as a policy instrument used to appear intensively in natural, economic and social policy. For the welfare states in Europe planning has been a central and irreplaceable policy instrument. Gradually, environmental dimensions have been taken into account, especially through the appearance of environmental problems and the idea of sustainable development. Planning can promote environmental sustainability examining the concept of development which meets environmental, social and economic needs. It can be used to regard both present and future generations’ needs. Planning as a policy instrument also encourages spatial integration of development perspectives and indicates how social cohesion, regional innovation and sustainable development can interplay. Spatial planning is an important policy instrument in coastal zones. Coastal zone planning can also be seen as a process of generating guidelines for improving activities and resource utilization in coastal areas. Planning is in this view implementing most of the other policy instruments mentioned in this article. So to realize the part of such plans needs often both, economic legal and cultural measures.
The system approach framework (SAF) can be seen as a planning instrument in itself.

== Economic instruments ==
Whereas legislative policies mainly consist of enforcements and restrictions, economic instruments are designed to provide more positive or negative financial incentives to promote or prevent more forms of production and consumption. Economic instruments include selective taxes and fees, as well as various kinds of subsidies, grants and tax exemptions, for both companies and individual citizens. The key feature of all these measures is that the authorities are involved at one end of the financial transaction. Through another type of economic instrument, the authorities can also set favourable frameworks for financial transactions within the private sector. Such instruments include e.g. the deposits paid on returnable drinks containers, and emissions trading schemes. The EU has developed a systemized overview of the use economics in environment policy on the European level.

'''Taxes''' are unreciprocated in the sense that benefits provided by government to taxpayers are not normally in proportion to their payments. The term “taxes” sometimes includes both taxes and, fees and charges (OECD 2008)[http://www2.oecd.org/ecoinst/queries/]. EU has over time developed a series of environmentally related taxes. Taxes have been an effective policy instrument in the so called welfare state the last 50 year. The major principle of taxes is to distribute and redistribute goods and “bads”. In environmental policy in general and coastal zone management especially, the rule is to implement the ‘polluter-pays’ principle. Environmentally related taxes can be defined as any compulsory payment to general government.

'''Subsidies''' are positive economic instruments to support political wanted production or consumption. In some cases, subsidy may refer to favoring one type of production or consumption over another, effectively reducing the competitiveness or retarding the development of potential substitutes. For instance, it has been argued that one can subsidy the use of alternative energy sources to increase their commercial development, and at the same time reducing use of non-renewable resource. The government can create incentives for sustainable behaviour by providing funds to start up sustainable projects create or update infrastructure to make industries more sustainable, etc. For example, the government can give a subsidy to farmers so that they can improve their irrigation systems to use less water.
Subsidies can also be given to ecological friendly tourist arrangers etc. Consumption related subsidies can be given indirectly to household when purchase of environmental friendly technology or goods. Removal of established subsidies is also a policy instrument.

== Legal and legislative measures ==

===The legal system===
Rules, laws and other measures that belong to the legal system are important regulative tools in coastal zone management and in society in general. This type of political tool differs from other tools because it implies norms with positive and negative sanctions. The law gives a system of rules, usually enforced through a set of institutions. It shapes politics, economics and society in numerous ways and serves as a primary social mediator of relations between people and between the people and the rulers. Each country (see State law) has often its own legal system but and underlines the state sovereignty. In the European Union the Court of Justice takes an approach mixing civil law (based on the treaties) with an attachment to the importance of case law.

===Legislations and regulations===
There are several generally accepted principles and characteristics of the implementation of ICZM .
One of these is legal support, which provides application of law as the regulative mechanism of coastal management. Rules and legal regulations can imply different measures from the sizes of fisher boats to water directives. It is meant to regulate activity that affects the sustainability of a coastal zone.
The legislative measures are related to bans, commands, rights and regulations. The use of sanctions when breaking rules, make them effective, but also politically controversial.
Harmful environmental impacts are largely controlled through the compulsory environmental permits that cover all kinds of potentially risk activities. Other environmental legislations have been enacted to prohibit the use of certain harmful substances, to set limits on emissions, to enforce certain technical standards, to make producers responsible for their products as waste, to limit certain activities in special areas such as nature reserves or car-free areas in cities, and to control land/coast use planning.
Access control measures like licenses for fisheries or other activities in the coastal area are also a type of legal instruments used in CZM. So are protection areas; such as national parks, conservation programs etc. These kinds of legal instruments can be part of a constructed Simulation Model for delivery of the specified outputs in SAF.
Legislations are perhaps the most foresighted instrument in a System Approach Framework because it’s the hard type of policy instrument (SAF). The effect of rules and regulations are based on its how legitimate it is. Legitimacy is given by public support; and in lack of legitimacy one can use force. There are of course democratic arguments against using force. Laws and legislations are in sum a highly predictable instrument, but at the same time difficult to pass formally.

== Technology as a policy tool ==

Over the course of human history, technological innovation has reshaped societies and changed our relationship to the natural world. An examination of past innovation demonstrates the enormous transformative potential of technology. We live in an era of accelerated technological change. Advances in biotechnology and information technology (and promised advances in cognitive science and nanotechnology) touch many aspects of our lives - from the way food is produced and processed, to the treatment of human illness, to how we communicate with each other. Technology is in this article seen as a policy tool. It is a way to get and give information and solve social and environmental challenges.
Environmental Technologies, i.e. on cleaner and resource efficient technologies which can decrease material inputs, can contribute to reduce energy consumption and emissions, recover valuable by-products, minimise waste disposal problems or some combination of these.
In aquaculture and agriculture, environmental technology are used to secure clean, energy saving and protective production. For waste - recycling & processing, waste is not considered as a pollutant but as a resource to be managed and processed for further re-use. Water - Sustainable use focuses on technologies and programmes aimed at improving the efficiency of water use and re-use, i.e. innovation in energy-efficiency technology.
Environmental technologies span a very wide range of applications – from an innovative control system that optimises a building’s heating, to a new product for cleaning up industrial effluent. One conserves energy and reduces CO2 emissions, while the other prevents harmful pollution from entering the ecosystem. Both help to make economic and social development sustainability.
Flood protection, piers, moles and jetties are important technical tools in CZM. Construction a jetty can retain the drifting sediment in rivers, while piers and moles often are breakwater constructions.
A main point here is that technology is a tool to bring forth improvement of action. Improvement of action is for example to make people sort garbage and recycle or use transportation that are cleaner than the alternative. In this way technology is a help for both politicians and users to make it easier to change behavour in a positive way.
A greater understanding of complex interactions between nutrients, bacteria and cultured organisms, together with advances in technology and hydrodynamics applied to pond and tank design, have enabled the development of closed systems. These have the advantage of isolating the aquaculture systems from natural aquatic systems, thus minimizing the risk of disease or genetic impacts on the external systems.

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|<center>The main authors of this article are [https://marineinfo.org/imis?module=person&persid=17870 Skorstad, Berit], Giordano,Laura and [https://marineinfo.org/imis?module=person&persid=17847 Sandberg, Audun]<br><small>Please note that others may also have edited the contents of this article. </small> </center>
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{{Spicosa}}

==External link==
[http://www.coastal-saf.eu/index.shtml System Approach Framework (SAF)]

==References==
<references/>

[[Category:Integrated coastal zone management]]

Marine biological valuation

2026-11-10T12:00:50Z

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{{Definition|title= Marine biological valuation
|definition= The intrinsic value of marine biodiversity, without reference to anthropogenic use (Derous et al. 2007a)<ref name=D>Derous, S., Agardy, T., Hillewaert, H., Hostens, K., Jamieson, G., Lieberknecht, L., Mees, J., Moulaert, I., Olenin, S., Paelinckx, D., Rabaut, M., Rachor, E., Roff, J., Stienen, E.W.M., van der Wal, J. T., van Lancker, V., Verfaillie, E., Vincx, M., Weslawski, J.M. and Degraer, S. 2007a. A concept for biological valuation in the marine environment. Oceanologia 49: 99-128</ref>.}}

==Development of biological valuation approaches==
Current attempts to valuate nature are based largely on two papers published by Costanza et al. (1997)<ref>Costanza, R., D'Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naem, S., O'Neil, R.V., Paruelo, J., Raskin, R.G., Sutton, P. and van den Belt, M. 1997. The value of the world ecosystem services and natural capital. Nature 387: 253-260</ref> and Costanza (1999)<ref>Costanza R. 1999. The ecological, economic and social importance of the oceans. Ecological Economics 31: 199-213</ref>, which set forth the foundation for assessing the value of environmental goods and services in monetary terms. However, challenges to purely economic valuations of nature were soon recognized <ref>Daily, G. (Ed.). 1997. Nature's services: societal dependence on natural ecosystems. Island Press, Washington DC</ref>.
This article presents a concept for biological valuation in the marine environment developed by Derous et al. (2007a), based on an international workshop held in 2004 and an extensive literature review <ref name=D></ref>. The purpose of marine biological valuation is to assess the intrinsic biological value of marine areas and their subzones. This can be done on a continuous or discrete value scale, e.g. high, medium and low value<ref name=D></ref>. Biological valuation is not a process to select areas for conservation according to quantitative objectives, but gives an overview of the integrated biological value of the different subzones within a study area (relative to each other). The decision to include one or more subzones in a marine reserve cannot be made on the basis of the outcome of a biological valuation, because the latter process does not take into account management criteria and quantitative conservation targets.

==Biological valuation methodology==
Different definitions of 'marine biological value' are currently found in the literature. What is meant by 'value' is directly linked to the objectives behind the process of valuation (e.g. conservation, sustainable use, preservation of biodiversity, etc.). Discussions on the value of marine biodiversity almost always refer to the socio-economic value of biodiversity (i.e. the so-called value of the goods and services provided by marine ecosystems, or the value of an area in terms of importance for human use), and attempts to attach a monetary value to the biodiversity in an area (see [[Total Economic Value]]). Many approaches try to highlight only the most important sites in a region in order to designate priority sites for conservation. These priority sites are often chosen on the basis of the hotspot approach, which is used to select sites with high numbers of rare/endemic species or high species richness. In this article 'marine biological value' is defined as follows: 'the intrinsic value of marine biodiversity, without reference to anthropogenic use'. This definition is similar to the definition of value of natural areas of Smith and Theberge (1986)<ref>Smith P.G.R. and Theberge J.B. 1986. A review of criteria for evaluating natural areas. Environ. Mgmt 10: 715–734</ref>: 'the assessment of ecosystem qualities per se, regardless of their social interests' (i.e. their intrinsic value). By 'ecosystem qualities' the authors of the latter paper covered all levels of biodiversity, from genetic diversity to ecosystem processes. The purpose of marine biological valuation is to provide subzones within the target study area with a label of their intrinsic biological value (on a continuous or discrete value scale, e.g. high, medium and low value). Subzones are defined as subregions within the study area that can be scored relative to each other, against a set of biological valuation criteria. The size of these subzones depends on the size of the study area, on the biodiversity components under consideration and on the amount of available data and should therefore be decided on a case by case basis. In contrast to the hotspot approach (i.e. identification of priority areas for conservation), we do not want to highlight solely the most valuable subzones. The product of the valuation process, i.e. the intrinsic values of the subzones, can then be presented on marine Biological Valuation Maps (BVMs), as further explained in the article [[Valuation and assessment of biodiversity]]. The BVM can serve as a baseline map showing the distribution of complex biological and ecological information. The marine biological valuation methodology is designed to integrate all available biological information on an area into one indicator. This methodology can be used in every marine environment, regardless of the amount and quality of the available biological data or the habitat type. It yields relative results that allow comparisons between subzones within a study site, but no absolute values that could be used to compare different study areas<ref name=P>Pascual, M., Borja, A., Eede, S.V., Deneudt, K., Vincx, M., Galparsoro, I. and Legorburu, I. 2011. Marine biological valuation mapping of the Basque continental shelf (Bay of Biscay) within the context of marine spatial planning. Estuarine, Coastal and Shelf Science 95: 186-198</ref>.
In contrast to many other approaches, no single measures of biodiversity (such as species richness or occurrence of flagship or keystone species) are used in this methodology, as these would not reflect total biodiversity or would not adequately mirror the complex marine biological systems <ref name-D></ref>.

In a first approach, five valuation criteria were selected <ref name=D></ref> . The three first-order criteria were rarity, aggregation and fitness consequences. In addition, the two modifying criteria naturalness and proportional importance were included. The criteria are defined in Table 1.

''Table 1. Set of marine valuation criteria and their definitions''
{| class="wikitable"
|-
! !! Valuation criterion !! Definition
|-
! 1st order criteria
| Rarity || Degree to which an area is characterized by unique, rare or distinct features (landscapes/habitats/ communities/species/ecological functions/ geomorphological and/or hydrological characteristics) for which no alternatives exist.
|-
!
| Aggregation|| Degree to which an area is a site where most individuals of a species are aggregated for some part of the year or a site which most individuals use for some important function in their life history or a site where some structural property or ecological process occurs with exceptionally high density.
|-
!
| Fitness consequences || Degree to which an area is a site where the activity(ies) undertaken make a vital contribution to the fitness (= increased survival or reproduction) of the population or species present.
|-
! Modifying criteria
| Naturalness || The degree to which an area is pristine and characterized by native species (i.e. absence of perturbation by human activities and absence of introduced or cultured species).
|-
!
| Proportional importance|| Global importance: proportionof the global extent of a feature (habitat/seascape) or proportion of the global population of a species occurring in a certain subarea within the study area.
Regional importance: proportion of the regional (e.g. NE Atlantic region) extent of a feature (habitat/seascape) or proportion of the regional population of a species occurring in a certain subarea within the study area.
National importance: proportion of the national extent of a feature (habitat/ seascape) or proportion of the national population of a species occurring in a certain subarea within territorial waters.
|}

In a second approach, the concept of marine biological valuation as described above was reorganized to avoid double counting of scores (i.e. lumped criterion 'aggregation-fitness consequences') and to allow a more logical order of the steps which should be made during valuation (i.e. assessing the biological value at two different scales instead of incorporation of 'proportional importance' as a valuation criterion)<ref name=DD>Derous, S., Austen, M., Claus, S., Daan, N., Dauvin, J.-C., Deneudt, K., Depestele, J., Desroy, N., Heessen, H., Hostens, K., Marboe, A.H., Lescrauwaet, A.-K., Moreno, M.P., Moulaert, I., Paelinckx, D., Rabaut, M., Rees, H., Ressurreicao, A., Roff, J., Santos, P.T., Speybroeck, J., Stienen, E.W.M., Tatarek, A., Hofstede, R.T., Vincx, M., Zarzycki, T. and Degraer, S. 2007b. Building on the concept of marine biological valuation with respect to translating it to a practical protocol: Viewpoints derived from a joint ENCORA-MARBEF initiative. Oceanologia 49: 579-586</ref>. 'Rarity' was retained as a valuation criterion while 'naturalness' was excluded from the concept.

Although the concept of biodiversity as a valuation criterion is highly attractive to managers, the practice of distilling biodiversity to a single index or a few dimensions is unjustified<ref>Margules C.R. and Pressey R. L. 2000. Systematic conservation planning. Nature 405: 243–253</ref><ref>Price, A.R.G. 2002. Simultaneous 'hotspots' and 'coldspots' of marine biodiversity and implications for global conservation. Mar. Ecol. Prog. Ser. 241: 23–27</ref><ref>Purvis A. and Hector A. 2000. Getting the measure of biodiversity. Nature 405: 212–219</ref>, which is why biodiversity was not directly used as a criterion in the present valuation concept. A more general framework for the assessment of biodiversity is needed that uses available information from a range of organizational levels (genes, species, communities, ecosystems) and considers the relationships among these levels. It is also emphasized that, in addition to biodiversity 'structures', there is also a need to include biodiversity processes such as aspects of the functioning of ecosystems, which could even be more important than high species richness or diversity indices in certain low biodiversity sites like estuaries<ref>Attrill, M. J., Ramsay, P.M., Myles, T.R. and Trett, M.W. 1996. An estuarine biodiversity hotspot, J. Mar. Biol. Assoc. U. K. 76: 161–175</ref>. Bengtsson (1998)<ref>Bengtsson J., 1998, Which species? What kind of diversity? Which ecosystem functioning? Some problems in studies of relations between biodiversity and ecosystem function. Appl. Soil Ecol. 10:191–199</ref> also stated that biodiversity is an abstract aggregated property of species in the context of communities or ecosystems, and that there is no mechanistic relationship between single measures of biodiversity and the functioning of the entire ecosystem. Ecosystem functioning can, however, be included indirectly in an assessment of biodiversity value, through the identification of functional species or groups and critical areas. Zacharias and Roff (2000)<ref>Zacharias M.A. and Roff J.C. 2000. A hierarchical ecological approach to conserving marine biodiversity. Conserv. Biol. 14: 1327–1334</ref> visualized the various components of biodiversity in their 'marine ecological framework' (going from the species to the ecosystem level and including both biodiversity structures and processes). Each of these components can be linked to one or more of the selected valuation criteria, which makes it unnecessary to include biodiversity as a separate valuation criterion. By using this 'framework' it could therefore be possible to apply the valuation criteria while integrating various components of biodiversity.

==Are all species equal?==
This approach was developed for the establishment of the best criteria for delineating [[Marine_Protected_Areas (MPAs)|marine protected areas]]. Since any kind of valuation requires ranking selected objects as more or less valuable, it raises ethical and philosophical questions, namely, whether all species are equal or not. Some recent studies discuss this dilemma, including Linder (1988)<ref>Linder, D.O. 1988. Are all species created equal.? and other questions which are shaping wildlife law. Harvard Environmental.Law Review 12, 157pp.</ref>, Schmidtz (2002)<ref>Schmidtz, D. 2002. Are all species equal.? Journal.Applied Philosphy 15: 57- 67</ref>, Singer (1989)<ref>Singer, P. 1989. All animals are equal. In: Animal.rights and human obligations. Edited T. Regan & P. Singer. Englweood Cliffs, NJ, Prentice Hall</ref>, and Jennings (2009)<ref>[http://www.nature.org/tncscience/bigideas/people/art23931.html Jennings M 2009 The next big ideas in conservation. Are all species equal? The Nature Conservancy]</ref>. Although it is accepted that all species are equal in moral terms, their contributions to ecosystem structure and function differ, and this can be assessed in scientific terms. [[Phylogenetic tree|Phylogenetic]] relationships can also be taken into account when considering biological value: so has a species that is one of hundreds in a single genus a lower importance for conservation than a species that is the only one in its order.

==Biological valuation maps==
[[Valuation and assessment of biodiversity|Biological valuation maps (BVMs)]], i.e. maps showing the intrinsic biodiversity value of subzones within a study area, would provide a useful 'intelligence system' for managers and decision makers. Such maps would need to make best use of available data sets, compiling and summarizing relevant biological and ecological information for a study area, and allocating an overall biological value to different subzones. Rather than a general strategy for protecting areas that have some ecological significance, biological valuation is a tool for calling attention to areas which have particularly high ecological or biological significance and to facilitate provision of a greater-than-usual degree of risk aversion in management of activities in such areas.

[[Image:MarBiolValuationBelgium.jpg|thumb|center|600px| Biological valuation maps of areas located near three main harbours at the Belgian coastal zone: (a) Nieuwpoort (Lombardsijde); (b) Oostende (Oostende-East); (c) Zeebrugge (Baai van Heist). The subtidal and intertidal parts of the subzones were assessed separately. (Vanden Eede et al. 2014)<ref name=E>Van den Eede, S., Laporta, L., Deneudt, K., Stienen, E., Derous, S., Degraer, S. and Vincx, M. 2014. Marine biological valuation of the shallow Belgian coastal zone: A space-use conflict example within the context of marine spatial planning. Ocean and Coastal Management 96: 61-72</ref>.]]

Biological value is not a direct measure of ecosystem health, although areas regarded as of high biological value are often considered to be valuable providers of [[Total Economic Value|socio-economic goods and services]] and are of high quality in terms of environmental health. The main difference is, however, that biological valuation focuses on the features of [[species]] and communities themselves, and not on the contamination or the extractable/usable part of the ecosystem.

Therefore marine biological valuation provides a comprehensive concept for assessing the intrinsic value of the subzones within a study area. The [[Valuation and assessment of biodiversity|biological valuation maps]] can also be used as [[baseline]] maps for future [[spatial planning]] in the marine environment. <ref name="ma">[http://www.marbef.org/documents/glossybook/MarBEFbooklet.pdf Heip, C., Hummel, H., van Avesaath, P., Appeltans, W., Arvanitidis, C., Aspden, R., Austen, M., Boero, F., Bouma, TJ., Boxshall, G., Buchholz, F., Crowe, T., Delaney, A., Deprez, T., Emblow, C., Feral, JP., Gasol, JM., Gooday, A., Harder, J., Ianora, A., Kraberg, A., Mackenzie, B., Ojaveer, H., Paterson, D., Rumohr, H., Schiedek, D., Sokolowski, A., Somerfield, P., Sousa Pinto, I., Vincx, M., Węsławski, JM., Nash, R. (2009). Marine Biodiversity and Ecosystem Functioning. Printbase, Dublin, Ireland ISSN 2009-2539]</ref>

[[Image:val1.jpg|thumb|centre|650px|Biological valuation of seabed communities in Polish Exclusive Economic Zone ]]
==Recent use of the biological valuation approach==
After its initial development in 2007, the biological valuation method was applied in Belgium, Portugal, Poland, the UK and Denmark. Only few case studies can be found in online publications that used this methodology after 2009. At the Bay of Biscay in the Basque continental shelf, a biological valuation map was created and used to identify biodiversity hotspots in 2011 <ref name=P></ref>. Moreover, Vanden Eede et al. (2014)<ref name=E></ref> continued the biological valuation of the Belgian North Sea coast, this time based on an R-script developed by the Flanders Marine Institute (VLIZ).

==Biological valuation vs. ecosystem service assessments==
An alternative method to valuate nature is the concept of [[ecosystem services]], which has gained strong momentum and popularity over the past 20 years<ref>Costanza, R., de Groot, R., Braat, L., Kubizewski, I., Fioramonti, L., Sutton, P., Farber, S. and Grasso, M. 2017. Twenty years of ecosystem services: How far have we come and how far do we still need to go? Ecosystem services 28: 1-16</ref>. Ecosystem services are commonly defined as “the benefits people obtain from ecosystems” <ref>Millennium Ecosystem Assessment (MAE) (2005): Ecosystems and Human Well-being: Synthesis. Island Press, Washington, DC</ref> or “the direct and indirect contributions of ecosystems to human well-being” <ref>The Economics of Ecosystems and Biodiversity (TEEB) 2010. The economics of ecosystems and biodiversity: mainstreaming the economics of nature: a synthesis of the approach, conclusions and recommendations of TEEB (No. 333.95 E19). UNEP, Ginebra</ref>. In contrast to the biological valuation method, which does not incorporate anthropogenic use, ecosystem services are therefore completely anthropocentric.
In coastal and marine environments, the valuation of ecosystem services has become increasingly important<ref>Barbier, E.B. 2012. Progress and Challenges in Valuing Coastal and Marine Ecosystem Services. Review of Environmental Economics and Policy 6: 1-19</ref>. Ecosystem service assessments are recognized to have a high potential for applications in [[Marine Spatial Planning - the need for a common language|marine spatial planning]] <ref>Böhnke-Henrichs, A., Baulcomb, C., Koss, R., Hussain, S.S. and de Groot, R.S. 2013. Typology and indicators of ecosystem services for marine spatial planning and management. Journal of Environmental Management 130: 135-145</ref> or [[Integrated Coastal Zone Management (ICZM)]]<ref>Elliff, C.I. and Kikuchi, R.K.P. 2015. The ecosystem service approach and its application as a tool for integrated coastal management. Natureza y Conservação 13: 105-111</ref>. For example, a nation-wide assessment of coastal and marine ecosystem services was recently conducted in the UK, with the aim to contribute to a decision support system for adaptive coastal management <ref>National Ecosystem Assessment (NEA) 2011. UK National Ecosystem Assessment : Technical report. UNEP-WCMC, Cambridge</ref>.
One reason why the biological valuation method is not as often applied in decision-making contexts might be that a purely biological valuation is by definition not suitable to assess impacts of human management:
''"Biological valuation maps give no information on the potential impacts that any human activity could have on a certain subzone, since criteria like vulnerability and resilience are deliberately not included in the valuation scheme...''". (Derous et al. 2007a) <ref name=D></ref>.
Further non-biological assessments are required to allow the use of biological valuation maps as decision-support tools for marine or coastal management.

== Related articles ==
:[[Valuation and assessment of biodiversity]]
:[[Ecosystem services]]
:[[Total Economic Value]]
:[[Economic valuation of goods and services of the UK coastal and marine ecosystem]]
:[[Measurements of biodiversity]]
:[[Multifunctionality and Valuation in coastal zones: concepts, approaches, tools and case studies]]

== References ==
<references/>

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|<center>The main authors of this article are [https://marineinfo.org/imis?module=person&persid=35375 Meike Wege], [https://marineinfo.org/imis?module=person&persid=35372 Simone Krüger] and [https://marineinfo.org/imis?module=person&persid=35376 Marion Kruse] </center>
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[[Category:MarBEF Wiki]]
[[Category:Evaluation and assessment in coastal management]]
[[Category:Coastal and marine ecosystems]]

Light fields and optics in coastal waters

2026-11-10T12:00:50Z

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The quantitative study of underwater light fields in coastal waters and shelf seas has important applications in ecology, engineering and [[remote sensing]]. This article introduces the theoretical basis of optical measurements. Attention is paid to descriptors of light fields, optical properties of natural waters and light field modelling. For more information about the measurement of light fields, see also the article [[Optical measurements in coastal waters]].

==Introduction of underwater light fields==
===Relevance===
The quantitative study of underwater light fields in coastal waters and shelf seas has important applications in ecology, engineering and [[remote sensing]]. Underwater light fields:

# play an important role in determining rates of photosynthesis by phytoplankton and macrophytes, and therefore set limits on the productivity of marine ecosystems.
# influence the range at which objects are visible under water, which is of great significance for diving and engineering operations and also for visual interactions between predators and prey species.
# determine the volume reflectance of seawater which is important for [[optical remote sensing]].

===Dynamics of underwater light fields===
Variations in underwater light fields originate from changes in both solar illumination and seawater composition, and predicting this variability involves the study of radiative transfer in an optically complex medium. There is an extensive literature on underwater light fields and associated problems in marine optics, but the fundamental concepts are clearly laid out in the books by Kirk (1994<ref name="kirk">Kirk J T O 1994 Light and photosynthesis in aquatic ecosystems. Cambridge University Press, Cambridge, 410 pp.</ref>), Mobley (1994<ref name="mob">Mobley C D 1994 Light and water; radiative transfer in natural waters. Academic Press, San Diego, 592pp. ISBN 0125027508</ref>) and Bukata et al (1995<ref>Bukata R P, Jerome J H , Kondratyev K Y and Pozdnyakov D V 1995 Optical properties and remote sensing of inland and coastal waters. CRC Press, 384pp</ref>). One of the challenges posed by coastal light fields is the potential for interaction and between physical and biological factors. For example, sediment particles in suspension can limit the illumination of benthic photosynthetic organisms, but the presence of those organisms may stabilise the sediment surface and reduce the probability of sediment re-suspension taking place.

Underwater light fields are vulnerable to human activities. Anthropogenic disturbances such as eutrophication, dredging operations and accelerated soil erosion due to the de-afforestation of river catchments can modify underwater light climates in coastal regions. Increases in [[turbidity]] produced by these activities can damage important ecosystem components such as coral reefs and sea grass beds.

The underwater light field depends on:
# <u>the optical characteristics of sea water</u>: The optical characteristics of coastal waters are determined not only by water itself, but also by suspended particulate material (minerals, organic detritus and phytoplankton) and coloured dissolved organic matter. The presence of relatively high concentrations of dissolved organic matter or minerals often distinguishes coastal waters from those of deeper seas, and accounts for their green or brown colouration.
# <u>the conditions of illumination</u>: The conditions of illumination depend on solar angle, the degree and type of cloud cover, and the state of the sea surface. As a result, underwater light fields show strong diurnal and seasonal variability.

==Light field descriptors==

===Radiance and irradiance===
'''[http://en.wikipedia.org/wiki/Radiance Radiance]''' is the fundamental quantity in light field measurement. It is usually denoted <math>L(q,f,\lambda)</math> where the angles <math>q</math> (zenith) and <math>f</math> (azimuth) specify the direction in which the radiance is measured and <math>\lambda</math> is the wavelength. The units of radiance are W m<sup>-2</sup> nm<sup>-1</sup> sr<sup>-1</sup>. Measurements of the water-leaving radiance <math>L_w</math> just above the surface at <math>q = 0</math> (nadir viewing) are particularly important for [[remote sensing]].

'''Planar and scalar [http://en.wikipedia.org/wiki/Irradiance irradiances]''' <math>E_x(\lambda)</math> are generated by integrating radiances over defined intervals of solid angle <math>D_w</math>. They have units of W m<sup>-2</sup> nm<sup>-1</sup>. For planar irradiances, the radiances are multiplied by the cosine of their angle of incidence on the detecting plane before carrying out the integration. Scalar irradiances omit the cosine weighting. Measurements of planar irradiances are made using a diffusing disc as a collector, while scalar irradiances are measured use a diffusing sphere. Commonly used irradiances are summarized Table 1.

{| border="1" width="600px" cellspacing="0"
|+ '''Table 1: Commonly used irradiances'''
|-
! Quantity
! Name
! Angular limits
|-
| <math>E_{\theta}(\lambda)</math>
| Scalar irradiance
| whole sphere
|-
| <math>[E_{\theta}(\lambda]_u</math>
| Upward scalar irradiance
| lower hemisphere
|-
| <math>[E_{\theta}(\lambda]_d</math>
| Downward scalar irradiance
| upper hemisphere
|-
| <math>E_u(\lambda)</math>
| Upward planar irradiance
| lower hemisphere
|-
| <math>E_d(\lambda)</math>
| Downward planar irradiance
| upper hemisphere
|}

A full description of an underwater light field would involve the specification of the spectral and angular distribution of radiance as a function of depth and geographical location, but this degree of detail is impractically cumbersome. The quantities most frequently specified are upward radiances and upward and downward irradiances.

===Wavelength ranges===
Studies of underwater light fields are usually contained within a waveband of approximately 300-900 nm: outside these boundaries, absorption by water strongly limits light penetration. Photosynthesis and animal vision mainly utilise the wavelength region of 400-700 nm, but damaging radiation can affect photosynthetic organisms at ultra-violet wavelengths (300-400 nm) while the near infra red region (700-900 nm) is important for [[remote sensing]] applications.

===Measurement units===
Three systems of units may be encountered in the literature on underwater light fields:
# <u>Radiometric units</u>: In physical radiometry, light energy is measured in joules (J), radiometric power in watts (W or J s<sup>-1</sup>), and the source brightness as power per unit solid angle (W sr<sup>-1</sup>).
# <u>Quantum units</u>: In photochemistry and photobiology, where molecular events are driven by the absorption of individual quanta, it is often useful to measure light fields in terms of numbers of photons rather than energy. A convenient unit is the mol (Avogadro’s Number) of photons. In the photobiology literature, one mol of photons is often referred to as an einstein, but the unit is redundant. The energy associated with a single photon of a given wavelength in vacuo is <math>e = hc/\lambda</math>, where <math>h</math> is Planck’s constant and <math>c</math> the speed of light. The inverse wavelength dependence means that conversion between radiometric and quantum units (for example from W m<sup>-2</sup> s<sup>-1</sup> to mol photons m<sup>-2</sup> s<sup>-1</sup> in the case of irradiance) requires explicit knowledge of the spectral distribution of the light field. Integration of scalar quantum irradiance across the visible spectrum (400-700 nm) gives a measure of photosynthetically active radiation (PAR: mol photons m<sup>-2</sup> s<sup>-1</sup>).
# <u>Photometric units</u>: The visual effect of a given source of illumination depends on the spectral sensitivity of the human eye. This leads to a system of photometric units based on the lumen as the measurement of effective power, and is discussed in DeCusatis (1997<ref>DeCusatis C M (ed) 1997 Handbook of Applied Photometry. American Institute of Physics Press, New York, 484 pp.</ref>). Conversion between radiometric and photometric units has to take both the standard eye response curve and the spectral distribution of the light field into account.

==Optical properties of natural waters==
This section describes the inherent optical properties (IOPs) op natural waters. The total IOP of water is its own contribution and four types of optically significant constituents.

===Inherent optical properties (IOPs)===
The optical characteristics of a light-transmitting medium can be specified in terms of its inherent optical properties, which represent the effect of an optically thin slab of the medium on the transmission of a collimated light beam. The main IOPs are summarized in table 2:

{| border="1" width="500px" cellspacing="0"
|+ '''Table 2: Main Inherent Optical Properties'''
|-
| <math>a</math>
| absorption coefficient
| m<sup>-1</sup>
|-
| <math>b</math>
| scattering coefficient
| m<sup>-1</sup>
|-
| <math>c = a + b</math>
| attenuation coefficient
| m<sup>-1</sup>
|-
| <math>\beta</math>
| scattering phase function
| sr<sup>-1</sup>
|}

Formal definitions for these IOPs may be found in Mobley (1994<ref name="mob"/>). The absorption, scattering and attenuation coefficients have fairly obvious meanings, while the phase function is a measure of the relative angular distribution of the scattered light. The scattering coefficient (b) is often partitioned into forward and backwards components, and the <u>backscattering coefficient (bb)</u> is of great importance for determining the [[remote sensing]] reflection of a water body.

The <u>total IOPs</u> of a body of seawater can be considered as the sum of the partial contributions from water itself and a number of optically significant constituents. These constituents are generally divided into four classes:

#Phytoplankton cells and colonies (Phyt)
#Mineral suspended solids (MSS)
#Coloured dissolved organic matter (CDOM)
#Organic suspended solids or detritus (OSS)

The concentration of the photosynthetic pigment chlorophyll a (Chl, mg m<sup>-3</sup>) is often used as a proxy variable for phytoplankton biomass. Mineral particle and organic detritus concentrations (g m<sup>-3</sup>) are determined by filtering water samples through a fine glass fibre filter and measuring the dry weight of material retained before and after combusting the filter at 500°C to remove the organic portion. Since there is no standard method for measuring the mass concentration of coloured dissolved organic matter, it is conventionally measured as the absorption coefficient at 440 nm of seawater which has been passed through a membrane filter with a 0.2 μm pore size.

The total absorption coefficient can be written as the sum of the contributions of the individual constituents:

<math>a_{total} = a_{water}\, +\, a_{Phyt}\, +\, a_{MSS}\, +\, a_{CDOM}\, +\, a_{OSS} </math>

The scattering coefficient (<math>b</math>), attenuation coefficient (<math>c</math>) and phase function (<math>\beta</math>) can all be partitioned in a similar manner. In practice, however, the optical contributions of these four classes of material may not be completely distinct: [[algal bloom|blooms]] formed by phytoplankton groups such as coccolithophores and diatoms may generate significant concentrations of mineral particles (calcite and silica respectively), and organic detrital material may form flocs which incorporate suspended minerals.

===Specific optical properties and characteristics of constituents===
The optical contributions of the main classes of constituents can be calculated by multiplying the concentrations of each constituent by the value of its inherent properties expressed per unit concentration. The latter quantity is often referred to as a specific inherent optical property or specific optical cross section. For example:

<math>a_{MSS} = MSS \times a^*(MSS)</math>

where <math>MSS</math> is the concentration of suspended minerals and <math>a^*(MSS)</math> is the specific absorption cross section for this constituent, with units of m<sup>2</sup> g<sup>-1</sup>. The convention that seawater contains four classes of optically significant constituents tends to conceal the fact that there can be considerable variability in specific optical properties within each class of constituent. Moreover, optical characterisation of the four main classes of constituent is currently incomplete.
<br>

:<u>''Phytoplankton cells and colonies (Phyt)''</u>: A great deal of effort has been devoted to the study of the absorption and scattering characteristics of phytoplankton cells (see for example Sathyendranath et al 1987<ref>Sathyendranath S, Lazzara L, Prieur L 1987 Variations in the Spectral Values of Specific Absorption of Phytoplankton. Limnology and Oceanography 32: 403-415</ref>, Bricaud et al 1988<ref>Bricaud, A., Bedhomme, A.L. and A. Morel (1988). Optical properties of diverse phytoplanktonic species: Experimental results and theoretical interpretation, Journal of Plankton Research, 10, 851-873</ref> and Johnsen et al 1994<ref>Johnsen G, Samset O, Grauskog L and Sakshaug E 1994 In vivo absorption characteristics in 10 classes of bloom-forming phytoplankton: taxonomic characteristics and responses to photoadaptation by means of discriminant and HPLC analysis. Marine Ecology Progress Series 105:149-157</ref>). The absorption spectra generally show maxima around the main chlorophyll absorption peaks at 440 nm and 675 nm, with subsidiary features depending on the presence of accessory light harvesting and photoprotective pigments. Phytoplankton scattering poses considerable practical and theoretical challenges because of the wide range of size and structure exhibited by individual cells and colonies. A helpful review of the theoretical problems is given by Quirantes and Bernard (2004<ref>Quirantes A and Bernard S 2004 Light scattering by marine algae: two-layer spherical and nonspherical models. Journal of Quantitative Spectroscopy & Radiative Transfer 89: 311–321</ref>) and measurement issues are discussed in Volten et al.(1998<ref>Volten H, de Haan J F , Hovenier J W, Scheurs R, Vassen W, Dekker A G, Hoogenboom H J, Charlton F and Wouts R. 1998 Laboratory measurements of angular distributions of light scattered by phytoplankton and silt. Limnology and Oceanography 43: 1180-1197.</ref>). For all but the smallest species, phytoplankton scattering is strongly peaked in the forward direction. One interesting feature in the total scattering spectra is the presence of minima near the chlorophyll absorption peaks which is due to Kettler-Helmholtz anomalous dispersion. There is some evidence that the specific backscattering coefficients of most phytoplankton species are too low to account for the magnitude of water-leaving radiance signals observed from natural populations, but measurements in this area are imprecise and current theoretical models do not take the full structural complexity of phytoplankton cells into account.
:<u>''Mineral suspended solids (MSS)''</u>: The optics of some types of mineral particles have been systematically explored (Babin and Stramski 2005<ref>Babin M., and Stramski D 2005 Variations in the mass-specific absorption coefficient of mineral particles suspended in water. Limnology and Oceanography, 49, 756-767</ref>). Their absorption spectra are generally high in the blue wavebands and decrease towards the red, and for field samples their shape is often similar to that for CDOM. Scattering characteristics are influenced by size distribution and refractive index (Wozniak and Stramski 2004<ref>Wozniak, Slawomir B.; Stramski, Dariusz 2004 Modeling the Optical Properties of Mineral Particles Suspended in Seawater and their Influence on Ocean Reflectance and Chlorophyll Estimation from Remote Sensing Algorithms Applied Optics IP, vol. 43, Issue 17, pp.3489-3503</ref>). It is not clear whether laboratory samples of mineral dusts are representative of all the materials found in coastal locations.
:<u>''Coloured dissolved organic matter (CDOM)''</u> CDOM absorption has been extensively characterised. It is generally described by an exponential function of the form: <math>a(\lambda\,)_{cdom}=a(\lambda_{\theta})_{cdom}\, e^{-S(\lambda - \lambda_{\theta})}</math>. In which: <math>\lambda_{\theta}</math> is a reference wavelength (usually 440 nm) and <math>S</math> is a coefficient which has a typical value of 0.01 to 0.02 in UK coastal waters (Bricaud et al 1981<ref>Bricaud A, Morel A and Prieur L 1981 Absorption by dissolved organic matter of the sea (yellow substance) in the UV and visible domains. Limnology and Oceanography 26:43-53.</ref>). Light scattering by CDOM is generally assumed negligible, but it is possible that some of the coloured material passing through 0.2 μm filters is colloidal in nature and therefore capable of contributing to the total scattering coefficient.
:<u>''Organic suspended solids or detritus (OSS)''</u>: The optical properties of organic detritus are not well characterised. This is due to the wide range of material which falls under this classification, ranging from scenescent phytoplankton cells to faecal pellets in offshore waters and including terrestrial vegetable matter in estuaries. There is also the possibility that organic matter may form flocs which include mineral particles in estuaries and in post-bloom shelf-sea conditions.

===Other relevant parameters===
Changes in light field parameters with depth (<math>z</math>) are often approximately exponential in nature. For example, the attenuation of downward planar irradiance in a uniform water column can be written:

<math>E_d(\lambda, z) = E_d (\lambda, \theta)e^{-K_d z}</math>,

in which <math>K_d</math> is the vertical attenuation coefficient. Quantities such as <math>K_d</math> are relatively insensitive to input conditions at moderate solar angles and are frequently referred to as <u>apparent optical properties (AOPs)</u> (Kirk 1994<ref name="kirk"/>). Some examples of AOPs are:
* The attenuation coefficient for downwards planar irradiance (<math>K_d</math>)
* The attenuation coefficient for scalar irradiance (<math>K_{\theta}</math>)
* Irradiance reflectance (<math>R</math>)
* [[Remote sensing]] reflectance (measured just above the sea surface) (<math>R_{rs}</math>)
* The mean cosine (<math>\mu</math>)

[[image:uw_optics01.jpg|thumb|right|350px|Figure 1: Measurements of PAR at three contrasting stations in the Irish Sea in April (station 10) and November (stations 26 and 29)]]
<u>Photosynthetically available radiation (PAR)</u> is the integral of scalar irradiance, expressed in quantum units, over the 400 -700 nm waveband. The term <math>K_{PAR}</math>, defined by analogy with <math>K_{\theta}</math> and <math>K_d</math>, is sometimes used to describe the attenuation of PAR. However since the attenuation of light by seawater varies with wavelength, the reduction in PAR with depth can deviate from the exponential approximation in the upper part of the water column. Figure 1 shows the measured variability of PAR with depth for three contrasting stations in the Irish Sea.

The optical depth <math>z(\lambda;l)</math> is defined as the depth at which <math>E_d</math> is reduced to 1/e (~0.37) of its value immediately below the surface. This quantity is wavelength-dependent, as might be expected from the fact that the spectral distribution of the underwater light field changes with depth. The maximum depth at which significant photosynthesis can occur (the euphotic depth, <math>z_{eu}</math>) is conventionally taken to be the point at which PAR is reduced to 1% of its surface value (Kirk 1994<ref name="kirk"/>).

The <u>horizontal range of visibility</u> (<math>y</math>) at which a black target is judged to be visible to a human observer is empirically related to the attenuation coefficient <math>c</math> by the relationship:

: <math>y\, = 4.8 / c </math> .

A theoretical basis for this relationship, based on radiance transfer theory, is given by Zaneveld and Pegau (2003<ref>Zaneveld J R V and Pegau W S 2003 Robust underwater visibility parameter. Optics Express 11:2997-3009</ref>).

==Radiative transfer theory and light field modelling==
===The radiative transfer equation===
The propagation of light energy through a medium which absorbs, scatters and contains internal sources is determined by the radiative transfer equation, which is widely used in fields such as astronomy and atmospheric science as well as hydrological optics (Goody and Yung 1989<ref>Goody R M and Yung Y L 1989 Atmospheric radiation, theoretical basis. Oxford University Press, Oxford. 519pp.</ref>). In marine light fields, sunlight enters from above and is attenuated with depth (<math>z</math>). In the simple case where bottom reflectance can be neglected and the water is horizontally homogeneous, the change in monochromatic radiance in a given direction (<math>q,f</math>) as a function of depth (<math>z</math>) is given by

<math>\Large\frac{d L(z,q,f)}{dr}\normalsize = -cL(z,q,f) + L^*(z,q,f)+ S(z,q,f)</math>,

in which: <math>L^*(z,q,f)</math> represents the gain in radiance due to light scattered from adjacent paths and <math>S(z,q,f)</math> accounts for any internal sources. In coastal waters, the most important internal source terms arise from Raman scattering by water molecules and fluorescence from dissolved organic matter and phytoplankton pigments. For light-field modelling the radiative transfer equation is solved numerically using either Monte Carlo methods or more conceptually sophisticated mathematical techniques (Mobley 1994<ref name="mob"/>, Thomas and Stamnes 1999<ref>Thomas G E.and Stamnes K 1999 Radiative transfer in the atmosphere and ocean, Cambridge, New York, Cambridge University Press 517 p., ISBN 0521401240.</ref>). The discrete ordinates method is commonly used in optical oceanography and is implemented in the commercially available Hydrolight software package (Sequoia Scientific). In order to construct a light field model, it is necessary to specify the nature of the input illumination, the IOPs of the medium, and any internal source functions (Figure 2). Light field models can generate a complete set of radiance values, but their output is usually summarised as a set of AOPs and reflectances which corresponds to those most frequently measured.
[[image:uw_optics02.jpg|thumb|centre|750px|Figure 2: Input/output relationships for the numerical modelling of radiative transfer in shelf seas.]]

===Optical closure===
Ideally, it should be possible to construct a light field model of a coastal water column using measured values of the IOPs which would precisely replicate radiometric measurements made at the same time. This is known as <u>‘optical closure’</u>. It is difficult to achieve in practice for two main reasons. First, it places great demands on the appropriate calibration and deployment of the measuring instruments. Second, some key IOPs such as the scattering phase function are difficult to measure [[in situ]], and are usually estimated from the backscattering ratio (bb/b) using analytical functions. Figure 3 shows a typical attempt to achieve optical closure for a shelf sea station in the Irish Sea with constituent concentrations of: Chl 1.6 mg m<sup>-3</sup>, MSS 1.9 mg l<sup>-1</sup>, CDOM a440 0.2m<sup>-1</sup>. In this instance the match between measured and modelled <math>E_d</math> values is reasonably good, but the <math>L_u</math> plots diverge significantly below 5 m. The symbols in Figure 3 represent measurements made with a profiling radiometer (Satlantic SPMR) and are spaced at 1 m intervals from the sea surface. The lines indicate the output of Hydrolight calculations of downward irradiance (upper plot) and upward radiance (lower plot) which used [[in-situ]] measurements of IOPs as inputs. Absorption and scattering coefficients were measured using a dual tube photometer (Wet Labs ac-9) and backscattering coefficients measured using a Hydroscat 2 (HobiLabs) backscattering meter.

<blockquote style="background: rgb(245, 245, 245); border: 1px solid rgb(153, 153, 153);padding: 1em; width:600px; margin:0 auto">
{|
|-
| width=300px| [[image:uw_optics03a.jpg|300px]]
| width=300px| [[image:uw_optics03b.jpg|300px]]
|-
|+ align="bottom" style="caption-side: bottom; text-align: left;" | Figure 3: Typical results of an attempt to achieve optical closure for a station in the Irish Sea.
|}
</blockquote>

==See also==
===Internal links===
* [[Optical measurements in coastal waters]]
* [[Optical remote sensing]]
* [[General principles of optical and acoustical instruments]]
* [[Optical Laser diffraction instruments (LISST)]]
* [[Optical backscatter point sensor (OBS)]]
* [[Use of Lidar for coastal habitat mapping]]

===Further reading===
* Babin M and Stramski D 2002 Light absorption by aquatic particles in the near-infrared spectral region. Limnology and Oceanography 47:911-915
* Babin, M, Morel A, Fournier-Sicre V, Fell F and Stramski D 2003. Light scattering properties of marine particles in coastal and oceanic waters as related to the particle mass concentration. Limnology and Oceanography, 48, 843-859

==References==

<references/>

<div style = "float: center">
{| style="border:1px solid #abd5f5; background:#f1f5fc; margin:0em 0em 0em 5em;"
|<center>The main authors of this article are [https://marineinfo.org/imis?module=person&persid=14356 Alex Cunningham] and Leanne Ramage<br><small>Please note that others may also have edited the contents of this article. </small> </center>
----

* For other articles by this author see [[:Category:Articles by Leanne Ramage]]
* For other articles by this author see [[:Category:Articles by Alex Cunningham]]
* For an overview of contributions by this author see [[Special:Contributions/Alex.cunningham]]
|}

[[Category:Articles by Alex Cunningham]]
[[Category:Articles by Leanne Ramage]]
</div>

[[Category:Coastal and marine observation and monitoring]]

Hard coastal protection structures

2026-11-10T12:00:50Z

Admin: Text replacement - "http://www.coastalwiki.org/imis/imis.php?module=person&persid=" to "https://marineinfo.org/imis?module=person&persid="

Hard coastal protection structures are common worldwide. For example, the percentage of armoured coastline is about 16% along the North Sea coasts and more than 8% along the Mediterranean coasts<ref>European Environment Agency, 2006. The Changing Faces of Europe’s Coastal Areas. Publications of the European Communities</ref>. About 14% of the total US coastline is protected by hard structures<ref>Gittman, R.K., Fodrie, F.J., Popowich, A.M., Keller, D.A., Bruno, J.F., Currin, C.A., Peterson, C.H. and Piehler, M.F. 2015. Engineering away our natural defenses: an analysis of shoreline hardening in the US. Front. Ecol. Environ. 13: 301–307</ref>, and coastal structures exist along 9.4% of the coastline in the Great Barrier Reef World Heritage Area (Australia).<ref> Waltham, N.J. and Sheaves, M. 2015. Expanding coastal urban and industrial seascape in the Great Barrier Reef World Heritage Area: critical need for coordinated planning and policy. Mar. Pol. 57: 78–84</ref> Seawalls currently protect 7% of the coast of India, with another 7% planned or under construction<ref>CSIR, 2020. Guidelines for Protection and Control of Coastal Erosion in India. Council of Scientific and Industrial Research, National Institute of Oceanography, India</ref>. Mainland China has with 60% the greatest percentage of hardened coastline.<ref>Luo, S., Cai, F., Liu, H., Lei, G., Qi, H. and Su, X. 2015. Adaptive measures adopted for risk reduction of coastal erosion in the People's Republic of China. Ocean & Coastal Management 103: 134-145</ref>

This article provides an introduction to hard coastal protection structures. An overview is given of structures that are often used in practice. The conditions for applying hard structures are discussed together with their advantages and disadvantages. A list of authoritative literature references is provided and Coastal Wiki articles are indicated where a more detailed discussion of hard coastal structures can be found. Large parts of this article are taken from the coastal engineering handbook of Reeve, Chadwick and Fleming (2018)<ref> Reeve, D., Chadwick, A. and Fleming, C. 2018. Coastal Engineering: Processes, Theory and Design, Practice 3rd Edition. CRC press, 512 pp.</ref>.

==Introduction==

[[Image:TypesCoastalWorks.jpg|thumb|450px|right|Figure 1: Common types of coastal protection structures.]]

There is a wide range of coastal works that might be employed to tackle a particular situation, each of which may perform a number of different functions. They will also have differing engineering lifespans as well as different capital and maintenance cost streams. The potential economic benefits will also have a strong influence on the final solution that might be adopted whilst still conforming to the objectives and policies developed through the [[Shoreline management|Shoreline Management Plan and Strategy Study]]. Figure 1 shows some of the more common types of coastal works that are often used and include artificial [[Definitions of coastal terms#Headland|headlands]], [[groyne]]s, [[Detached breakwater|offshore breakwaters]], [[beach nourishment]] and [[seawall]]s. The characteristics of the coasts for which they are suited, the basic advantages and disadvantages are listed in this figure. CIRIA Report 153 <ref name=S>Simm, J.D., Brampton, A. H., Beech, N.W., Brooke, J.S. (Editors). 1996. Guidelines for the application of control works. Beach Management Manual. CIRIA report 153</ref> also provides a useful summary guideline for the application of hard construction works as given in Table 1. The comments provided are mainly of a technical nature; note that there are a number of wider environmental considerations that need to be considered in the context of a full appraisal (see the article [[Shoreline management]]).

Modern design practice places much emphasis on attempting to hold a healthy beach on the shoreline as the primary means of protection. A sufficiently substantial beach can accommodate the dynamic changes that are the result of differing climatic conditions. These so-called ‘soft’ solutions are generally considered to be more environmentally friendly than traditional ‘hard’ protection works. However, where human life may be at risk and high density, high value conurbations exist, the use of hard elements of a defence may be unavoidable.

==Conditions for applying hard coastal structures==
A good understanding of the coastal environment at a site under consideration is an essential prerequisite to assessing the ability of a coastal defence option to perform as it is intended. A complex interaction exists between the various elements defining the coastal environment. The introduction of coastal protection works will invariably modify nearshore processes in some way and it is important to account for that feedback effect. Coastal morphology at any location is the result of erosion and accretion patterns which, in turn, depend on the interaction of wave climate, currents and tides with this morphology. The causes and effects of coastal features must always be considered when dealing with works which affect littoral movement. The origin of beach material can be from inland sources brought to the coast by rivers or from the erosion of cliffs in the immediate or adjacent coastlines. Sometimes there can be shoreward pathways of sediment from offshore sources. In some cases, these processes may no longer be active and the beach may consist of relic materials.

Knowledge of the geology underlying the nearshore zone is important because a stratum that is different from the surface material can affect the way in which a beach behaves. A thin veneer of loose material on an erodible platform can act as an abrasive and accelerate erosion, whilst its existence on an impermeable base will be inherently unstable and more mobile than an equivalent deep beach. These factors are also material to the design of foundations of coastal structures.

{| style=background:ivory; cellspacing=1px cellpadding=5px align=center width=100%
|+ Table 1. Guidelines for the application of hard coastal structures <ref name=S></ref>.
|- style="font-weight:bold; text-align:center; background:lightblue"
! width="15% style=" border:1px solid blue;"| Structure Type
! width="30% style=" border:1px solid bleu;"| Characteristics coast
! width="25% style=" border:1px solid blue;"| Advantages
! width="30% style=" border:1px solid blue;"| Disadvantages
|-
| style="border:2px solid lightblue;text-align:center"| [[Groyne]]s
| style="border:2px solid lightblue;text-align:left"| Shingle beach: any tidal range; Sand: micro-tidal only; Low net littoral drift (gross drift may be high); Low structures suitable for low wave energy; Large mound type structures suitable for high wave energy.
| style="border:2px solid lightblue;text-align: left"| Allows for variable levels of protection along frontage schemes to put coastal policies into practice.
| style="border:2px solid lightblue;text-align: left"| Can induce rip currents which increase erosion, particularly on sand beaches; Vertical structures potentially unstable in case of large cross-structure beach profile differences; Requires recharge to avoid downdrift erosion.
|-
| style="border:2px solid lightblue;text-align:center"| [[Detached breakwater]]s
| style="border:2px solid lightblue;text-align: left"| Shingle beach: any tidal range; Sand: micro-tidal only; Dominant net drift direction; Constant wave climate, not storm dominated; Creation of amenity pocket beaches or salients.
| style="border:2px solid lightblue;text-align: left"| Allows for variable levels of protection along frontage.
| style="border:2px solid lightblue;text-align: left"| Large visual impact particularly with macro-tides; May cause downdrift beach erosion and leeward deposition of fine sediment and flotsam; Inshore tidal currents may be intensified; May cause hazardous rip currents; Difficult to construct due to cross-shore location; Difficult to balance impact under storms and long-term conditions; Difficult to balance impact on both shingle and sand transport.
|-
| style="border:2px solid lightblue;text-align:center"| Shore-connected breakwaters
| style="border:2px solid lightblue;text-align: left"| Bay-type shoreline, Shingle beach: any tidal range; Sand: limited effect with macro-tides; Dominant net drift direction; Any wave climate; Strong shoreline tidal currents ("fishtails" only); Creation of amenity pocket beaches.
| style="border:2px solid lightblue;text-align: left"| Allows for variable levels of protection along frontage; Can be used to create amenity features; Longshore and cross-shore control.
| style="border:2px solid lightblue;text-align: left"| May cause leeward deposition of fines and flotsam; Little design guidance at present.
|-
| style="border:2px solid lightblue;text-align:center"| [[Seawall]]/[[Revetment]]s
| style="border:2px solid lightblue;text-align: left"| Sand or shingle beach: any tidal range, any wave climate; Low gross drift rate; Provides secondary line of defence where beach cannot be designed to absorb all wave energy during extreme events.
| style="border:2px solid lightblue;text-align: left"| Well developed design methods; Provides equal protection along frontage; Can be designed to support a sea front development.
| style="border:2px solid lightblue;text-align: left"| No drift control; Beach lowering; May become unstable if erosion continues.
|-
| style="border:2px solid lightblue;text-align:center"| [[Sill]]s
| style="border:2px solid lightblue;text-align: left"| Shingle or sand beach; Low wave energy; Low and variable drift; Submerged with micro-tides, regularly exposed with macro-tides.
| style="border:2px solid lightblue;text-align: left"| Well developed design methods; Provides equal protection along frontage; Can be designed to support a sea front development.
| style="border:2px solid lightblue;text-align: left"| Storms may remove beach irreversibly; Level of protection reduced during storm surge events.
|-
| style="border:2px solid lightblue;text-align:center"| Beach drainage systems
| style="border:2px solid lightblue;text-align: left"| Sand beaches, normally up to the high-water line; Any tidal range; Any wave climate or drift rate.
| style="border:2px solid lightblue;text-align: left"| Responds to beach developments.
| style="border:2px solid lightblue;text-align: left"| Limited experience of use; Effectiveness not clear; Long-term maintenance may be expensive; Risk of failure during short duration, extreme storms.
|}

A more detailed discussion of the coastal structures of Table 1 can be found in the articles:
* [[Groynes]] and [[Groynes as shore protection]]
* [[Seawalls and revetments]] and [[Seawall]]
* [[Bulkheads]]
* [[Revetments]]
* [[Detached breakwaters]], [[Detached shore parallel breakwaters]] and [[Applicability of detached breakwaters]]
* [[Floating breakwaters]]
* [[Coves]]
* [[Piers and trestles]]
* [[Beach drainage]]
* [[Stability of rubble mound breakwaters and shore revetments]]
* [[Ecological enhancement of coastal protection structures]]

==Further reading==

There are a number of publications and standards that deal with general facets of coastal structure design and include some excellent information and detailed guidance. These are:

* Coastal Engineering Manual. US Army Corps of Engineers (USACE), 2008
* The Rock Manual. The use of rock in hydraulic engineering (2nd edition).CIRIA. London, 2007
* A guide to managing coastal erosion in beach/dune systems. Scottish Natural Heritage, 2000. https://www.nature.scot/sites/default/files/2017-07/Publication%202000%20-%20Beach%20Dunes%20-%20a%20guide%20to%20managing%20coastal%20erosion%20in%20beach%20dune%20systems.pdf
* Rogers, J., Hamer, B., Brampton, A., Challinor, S., Glennerster, M., Brenton, P. and Bradbury, A. 2010. Beach Management Manual (second edition). CIRIA report C685.
* BS6349 (2013) 1 - 1. Maritime Works, General. Code of Practice for planning and design for operation. British Standards Institute (shopbsigroup.com)
* BS6349 (2016) 1 - 2. Maritime Works, General. Code of Practice for assessment of actions. British Standards Institute (shopbsigroup.com)
* BS6349 (2012) 1 - 3. Maritime Works, General. Code of Practice for geotechnical. British Standards Institute (shopbsigroup.com)
* BS6349 (2013) 1 - 4. Maritime Works, General. Code of Practice for planning and design of floating and mooring systems. British Standards Institute (shopbsigroup.com)
* BS6349 (2013) 5. Maritime Works. Code of Practice for dredging and reclamation. British Standards Institute (shopbsigroup.com)
* BS6349 (expected late 2016) 6. Maritime Works. Code of Practice for floating structures. British Standards Institute (shopbsigroup.com)
* BS6349 (1991). Maritime Structures - 7. Guide to the design and construction of breakwaters. British Standards Institute. Revision commenced 2016.
* Abbott, M.B. and Price, W.A. (eds.) 1994. Coastal, Estuarial and Harbour Engineers Reference Book. CRC Press.
* Pilarczyk, K.W. (ed.) 1990, Coastal Protection. A.A. Balkema (publisher), Rotterdam.
* Allen, R. T. L. 1998. Concrete in Coastal Structures. Thomas Telford.
* Fleming, C. A. 1990. Guide on the uses of groynes in coastal engineering. CIRIA report 119.
* PIANC 1992. Guidelines for the design and construction of flexible revetments incorporating geotextiles in marine environments. Committee II, Working Group No. 21. ISBN: 9782872230440.
* Van der Meer, J.W. 2018. EurOtop. Manual on Wave Overtopping of Sea Defences and Related Structures, www.overtopping-manual.com
* Brampton, A. (ed.) 2002. Design and Practice Guides, Coastal defences. Thomas Telford, London.
* Pilarczyk, K. W. and Van Overeem, J. 1987. Manual on artificial beach nourishment. CUR report, 130.
* Jensen, C. 2007. The rock manual - the use of rock in hydraulic engineering (2nd edition).CIRIA, CUR Centre For Civil Engineering and CETMEF.
* Besley, P. 1999. Wave Overtopping of Seawalls Design and Assessment Manual. HR Wallingford R&D Technical Report W178. Environment Agency.
* Bruun, P. 1989. Port Engineering .Gulf Publishing Company.
* McConnell , K. 1998. Revetment systems against wave attack: A design manual. Technical Report. Thomas Telford
* Thomas, R. S. and Hall, B. 1992. Seawall Design. Butterworth Heinemann/CIRIA, Oxford, UK
* Van der Meer, J.W. 2002.Technical Report Wave Run-up and Wave Overtopping at Dikes Publication. Technical Advisory Committee on Flood Defence (TAW), Delft
* Dean, R. and Dalrymple, R. 2010. Coastal processes with engineering applications, Cambridge University Press.

==References==
<references/>

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{| style="border:1px solid #abd5f5; background:#f1f5fc; margin:0em 0em 0em 5em;"
|<center>The authors of this article are [https://marineinfo.org/imis?module=person&persid=11189 Andrew Chadwick], [https://marineinfo.org/imis?module=person&persid=13423 Dominic Reeve] and [https://marineinfo.org/imis?module=person&persid=13372 Christopher Fleming]
</center>
|}

[[Category:Coastal protection]]
[[Category:Hard structures]]

Extreme storms

2026-11-10T12:00:49Z

Admin: Text replacement - "http://www.coastalwiki.org/imis/imis.php?module=person&persid=" to "https://marineinfo.org/imis?module=person&persid="

==Introduction==

[[Image:PrinosFig1.1.jpg|thumb|300px|left| Fig. 1a. Strong winds generating large waves and storm surge in Ft. Lauderdale, FL, during Hurricane Ernesto in 2006. (credit: U.S. Geological Survey, Department of the Interior/USGS, U.S. Geological Survey/photo by Susan Caplan) )]]
[[Image:PrinosFig1.2a.jpg|thumb|300px|right|Fig. 1b. Damage to beach front homes on Dauphin Island, AL, due to storm surge from Hurricane Katrina in 2005.(credit: NOAA - National Oceanic and Atmospheric Administration, U.S. Department of Commerce)]]
[[Image:PrinosFig1.3.jpg|thumb|300px|left|Fig. 1c. Wave overtopping a coastal breakwater, Hartlepool, UK. Courtesy of HR Wallingford.]]
[[Image:PrinosFig1.4.jpg|thumb|300px|right|Fig. 1d. Storm waves from Lake Erie wash over a beach at Point Pelee National Park, Ontario. (credit: Environment and Climate Change Canada/ Public Works and Government Services Canada / Richard Vroom, 1976)]]
[[Image:PrinosFig1.5.jpg|thumb|300px|left|Fig. 1e. Damages to ocean front homes during Hurricane Sandy on Fire Island, NY. (credit: U.S. Geological Survey, Department of the Interior/ USGS, U.S. Geological Survey/photo by: Cheryl Hapke) )]]
[[Image: EmbankmentOvertoppingGermany.jpg|thumb|300px|right|Fig. 1f. Wave overtopping of a coastal embankment in Germany caused by a storm wave event. (source: Leichtweiss-Institute for Hydraulics)]]

Extreme storms can be defined as intense storm events characterised by strong winds blowing over the surface of the sea, large and long waves that can travel long distances until they reach the shore and high water levels known as storm surge <ref name=USGS>U.S. Geological Survey (USGS), 2016. Coastal Change Hazards: Hurricanes and Extreme Storms, Available from: http://coastal.er.usgs.gov/hurricanes/extreme-storms, National Assessment of Storm-Induced Coastal Change Hazards, Available from: http://coastal.er.usgs.gov/hurricanes/sandy/ [accessed on 31-10-2016]</ref>. Such storms can significantly affect navigation and petroleum platforms and can cause a range of potential hazards to coastal areas, such as [[overwash]]ing and/or inundation, beach or shore erosion, as well as damages to coastal protection structures or to infrastructure of developed coastal areas (see Figs. 1a-1f). The most frequent natural hazards to coastal areas, namely flooding and erosion are usually induced by extreme storm events, resulting in lives lost, human injuries and damage to property or to the environment.

Extreme storms are usually defined as the sources of coastal flooding or erosion risk, transmitted to the receptors (society, economy, environmental values) through the pathways of the respective coastal hazard. The intensity of storm-induced coastal processes and the morphodynamic response of a coastal area to an extreme storm event depend strongly on the characteristics of the storm (i.e. storm peak, duration, directionality, energetic content), as well as on the characteristics of the coastal area (i.e. beach profile, gain size, relative orientation of the shoreline)<ref> Cooper, J.A.G., Jackson, D.W.T., Navas, F., McKenna, J. and Malvarez, G., 2004. “Identifying storm impacts on an embayed, high-energy coastline: examples from western Ireland”. Marine Geology, Vol. 210(1), 261-280.</ref><ref name=MJ>Mendoza, E.T. and Jiménez, J.A., 2006. “Storm-Induced Beach Erosion Potential on the Catalonian Coast”, Journal of Coastal Research, SI 48, 81-88.</ref>

The description of risk sources in coastal areas helps to deliver the hydrologic and hydraulic boundary conditions needed to describe the loading of defences or can be used as key input to calculate the probability of occurrence of a certain coastal hazard (i.e. coastal flooding or erosion). Main coastal risk sources include both intense meteorological synoptic-scale cyclonic events, the tropical cyclones which form almost exclusively over tropical seas, as well as marine storm events resulting from severe wave conditions and/or high sea levels (tide and storm surge) offshore and transformed to nearshore. Tsunamis, namely very long waves most often generated by seismic activity, also belong to coastal risk sources characterised by a high damage potential.
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==Tropical storms==

[[Image:PrinosFig2.jpg|thumb|400px|right|Fig. 2. Typical structure of a hurricane (credit: U.S. Geological Survey, Department of the Interior/USGS, U.S. Geological Survey/image credit: The COMET Program Steven Deyo /USGS Betsy Boynton)]]

[[Image:PrinosFig3.jpg|thumb|400px|right|Fig. 3. Tropical cyclone distribution around the globe. © British Crown Copyright, Met Office.]]

Tropical cyclones are intense local meteorological systems characterised by extremely low pressure in the cyclone center near the sea surface and caused by a combination of warm water, evaporation, swirling winds and other factors. The drag on the sea surface causes the wind to spiral in towards the center of the storm, transferring heat from the ocean surface to the air and therefore refuelling and perhaps strengthening the system (Fig. 2). The intensity of the tropical cyclone increases with lower sea-level pressures in the core of the storm, as well as with stronger winds near the sea surface.

In the Atlantic and Northeast Pacific, tropical cyclones are called hurricanes, while the terms typhoons and cyclones are used for similar types of disturbances in the Northwest Pacific and in the South Pacific and Indian Ocean, respectively (see Fig. 3). Therefore, aside from slightly different wind speeds, there is no difference between a hurricane, a typhoon, and a cyclone.

Most tropical cyclones form within the trade wind region, tracking from east to west, turning poleward under the influence of monsoon circulation and then continuing to turn towards the northeast due to western winds in the mid-latitudes<ref name=Stull> Stull, R.B., 2011. “Meteorology for Scientists and Engineers”, 3rd Edition, 938 pp, Free online for everyone worldwide under a Creative Commons license, ISBN 978-0-88865-178-5</ref>. The intensification stages leading to fully developed tropical cyclones include tropical disturbances, tropical depressions and tropical storms, distinctly separated based on the maximum wind speed near the sea surface.
For a tropical cyclone to form and develop there are seven main requirements<ref name=Stull></ref>:
* Sufficiently warm deep sea-surface temperatures,
* Enough Coriolis force to cause the tangential flow of air around the eye of the tropical cyclone,
* Atmospheric instability developed non locally to support deep thunderstorm convection,
* High humidity in the lower to middle levels of the troposphere,
* Low vertical wind shear allowing to create a low-pressure center at the sea surface where thunderstorm clusters can be formed,
* Enough relative vorticity at the lower part of the troposphere enabling the clustering of thunderstorms,
* A pre-existing low level focus or disturbance enabling horizontal convergence in the atmospheric boundary layer.
The reduced atmospheric pressure in the eye of the tropical cyclone combined with wind blowing towards the coast could form large propagating storm surges able to inundate very large areas of the shore and cause significant damages. High surface waves, generated by the total wind speed of the tropical cyclone relative to the surface, resulting as a vector sum of the translation and the rotation speed of the storm, could significantly increase the damage caused. The main coastal hazards resulting from a tropical cyclone include flooding caused by the fast propagating storm surge, high wind speeds causing significant damages inland, beach erosion, as well as wave scour at the toe of structures protecting coastal areas and wave battering of such structures<ref name=Stull></ref>.

Tropical storms can produce heavy rainfall in addition to storm surges. Flooding risks can be significantly increased when high storm surge levels slow down the runoff of rivers that drain a catchment subject to heavy precipitation. In this case, flood protection measures should consider the joint probability of high storm surge levels and heavy precipitation<ref>Xu, H., Ragno, E., Tan, J., Antonini, A., Bricker, J.D., Jonkman, S.N., Liu, Q. and Wang, J. 2023. Perspectives on Compound Flooding in Chinese Estuary Regions. International Journal of Disaster Risk Science 14: 269–279</ref>.

==Wave storms and [[storm surge]]s==
A storm can be simply defined as an intense atmospheric perturbation, which impacts directly on the sea surface causing significantly increased wave heights and sometimes high storm surges<ref name=BJ> Bosom, E. and Jiménez, J.A., 2011. “Probabilistic coastal vulnerability assessment to storms at regional scale: application to Catalan beaches (NW Mediterranean)”, Natural Hazards and Earth System Sciences, Vol. 11(2), 475-484.</ref>. Strong winds over the sea, especially those with large fetches acting for long durations, favor the air-sea momentum transfer<ref> Guimarães, P.V., Farina, L. and Toldo Jr, E.E., 2014. “Analysis of extreme wave events on the southern coast of Brazil”, Natural Hazards and Earth System Sciences, Vol. 14(12), 3195-3205.</ref>, possibly leading to high and long sea waves. Wave storms are usually defined as events of significant wave height, <math>H_s</math>, exceeding a predefined threshold (critical <math>H_s</math>) with a minimum duration. The duration of the storm starts when <math>H_s</math> exceeds the threshold and ends when <math>H_s</math> goes below it. Both the threshold of the storm event and its minimum duration are defined based on the objective of the study i.e. storms with a high flooding or erosion potential to the adjacent coastal area. Studies performed for the Spanish coast in the Mediterranean, define a wave storm as an event during which <math>H_s</math> overpasses the threshold of 2 m with a minimum duration of 6 h, as the limiting conditions required to significantly erode the Catalan coast<ref name=MJ></ref><ref name=BJ></ref>. Therefore, wave storms are considered to be sufficiently intense and durable to produce substantial impacts based on the objectives of each study. It is also quite common to define a maximum time interval for which the wave data fall below the threshold within a single wave storm event. For longer time intervals the storm is splitted in two different wave storm events, allowing for suites of low energetic events to be treated as independent wave storms. To determine wave storm events, long time series of wave data at quite a high temporal resolution (i.e. hourly data) should be made available. Such data can be acquired from a wave buoy network, measuring significant wave height, <math>H_s</math>, peak spectral wave period, <math>T_p</math>, and prevailing wave direction, <math>\theta</math>, or hindcast wave data can be utilised.
Sea level is composed of three components, namely the mean sea level, the tidal level and zero mean surge level (i.e. the meteorological residual)<ref> Pugh, D.T., 1987. “Tides, Surges and Mean Sea Level: a Handbook for Engineers and Scientists”, Wiley, Chichester, 472 pp.</ref>. The storm surge is the stochastic component of sea level mainly induced by the inverse barometer effect and strong winds. A storm surge event is defined in a similar manner to the wave storm event. Therefore, an appropriate threshold is defined and the event starts when the storm surge overpasses it and terminates when it gets below this minimum value. A minimum duration of each storm event is also considered. Sea level variations can be acquired from tide gauge records and satellite-altimeter data<ref> Menéndez, M., Méndez, F.J. and Losada, I.J., 2009. “Forecasting seasonal to interannual variability in extreme sea levels”, ICES Journal of Marine Science, Vol. 66, 1490-1496.</ref>.

==Methods to analyse extreme storms and predict return periods==

[[Image:PrinosFig4.jpg|thumb|400px|right|Fig. 4. Wave storm events and variables used in the POT method.]]

Once storm events (wave storms, storm surge events or wind storms) are identified, time series of storm peaks can be constructed defined by means of the maximum value within each event. These maxima should belong to independent storm events, therefore it is quite common to consider a minimum separation time interval between consecutive peak values <ref> Makris, C., Galiatsatou, P., Tolika, K., Anagnostopoulou, C., Kombiadou, K., Prinos, P., Velikou, K., Kapelonis, Z., Tragou, E., Androulidakis, Y., Athanassoulis, G., Vagenas, C., Tegoulias, I., Baltikas, V., Krestenitis, Y., Gerostathis, T., Belibassakis, K. and Rusu, E., 2016. “Climate change effects on the marine characteristics of the Aegean and Ionian Seas”, Ocean Dynamics, 1-33.</ref>. [https://en.wikipedia.org/wiki/Extreme_value_theory Extreme Value Analysis (EVA)] can then be performed to extract return levels of wave/ storm surge/ wind characteristics corresponding to defined return periods i.e. 50, 100, 1000 years. Extreme Value methods are utilized for the purpose of extrapolation to levels more extreme than those observed. Univariate Extreme Value Theory (EVT) includes models for<ref> Coles, S., 2001. “An introduction to statistical modeling of extreme values”, Springer Series in Statistics, Springer, Berlin, 209 pp.</ref>:
* Block maxima (the block size is usually considered equal to one year)
* Exceedances over high thresholds (Peaks Over Threshold (POT) models)
and are used according to data availability. The former models correspond to the family of the [https://en.wikipedia.org/wiki/Generalized_extreme_value_distribution Generalized Extreme Value (GEV) distribution], where the largest storms (i.e. the storm with the highest peak <math>H_s</math>) within each year are selected. The POT method, where all events exceeding a defined threshold <math>u</math> are considered, defines a two dimensional point process (<math>y, \; N_u</math>), where the excesses, <math>y</math>, of the threshold <math>u</math> follow a [https://en.wikipedia.org/wiki/Generalized_Pareto_distribution Generalised Pareto Distribution (GPD)], while the number of storms, <math>N_u</math>, is [https://en.wikipedia.org/wiki/Poisson_distribution Poisson distributed] (Fig. 4, Fig. 5).

[[Image:PrinosFig5.jpg|thumb|600px|center|Fig. 5. Surge levels (mean and 95% confidence intervals) against return period for a station off the Dutch coast. The parameters of the POT model are estimated using the maximum likelihood procedure (dashed line) and the Bayesian approach (solid line) using (a) non-informative prior distributions and (b) information from a neighbouring station<ref> Galiatsatou, P., Prinos, P. and Sánchez-Arcilla, A., 2008. “Estimation of extremes. Conventional versus Bayesian techniques”, Journal of Hydraulic Research, Vol. 46(2), 211-223.</ref>.]]

The most frequent natural hazards to coastal areas, such as coastal flooding and coastal erosion, are particularly likely when high tides, storm surge and/or large waves occur at the same time. Where the source of a hazard consists of more than one variables (i.e. coastal flooding caused by extreme wave heights and sea levels), it is necessary to consider the joint probability distribution of these variables<ref> Hawkes, P.J., Gouldby, B.P., Tawn, J.A. and Owen, M.W., 2002. “The joint probability of waves and water levels in coastal defence design”, Journal of Hydraulic Research, Vol. 40(3), 241-251.</ref>. Joint exceedance combinations of wave heights and sea levels with a given probability of occurrence are defined in terms of sea conditions in which a given wave height is exceeded at the same time as a given water level (or its surge component) being exceeded. There are different levels of complexity for joint probability methods but all require some assessment of the dependence between variables<ref> DEFRA/ Environment Agency Flood and Coastal Defence R&D Programme, 2005. “Joint Probability: Dependence Mapping and Best Practice”, Technical report on dependence mapping, R&D Technical Report FD2308/TR1.</ref>:

[[Image:PrinosFig6.jpg|thumb|400px|right|Fig. 6. Storm surge with maximum value, S, and associated fullness, F, of the entire storm surge curve - NN corresponds to “Normal Null” reference level fixed by the German law<ref name=Wahl></ref>.]]

* A relatively simple method uses the marginal distributions of the variables involved and an assessment of their dependence. The joint return period is expressed in terms of combinations of the marginal return periods.
* A more sophisticated approach involves fitting a probability distribution to the joint distribution of variables and extrapolating the joint density function. The benefit of this approach is that the return period of the response function can be easily determined, but a large amount of concurrent data of the variables is needed. For this approach Multivariate Extreme Value Theory and copula functions can be used to extract joint exceedance probabilities and joint return levels. Approaches based on [https://en.wikipedia.org/wiki/Copula_(statistics) copula functions] are able to model multivariate datasets with mixed marginal distributions and complex dependence structures<ref> Oumeraci, H., Kortenhaus, A., Burzel, A., Naulin, M., Dassanayake, D.R., Jensen, J., Wahl, T., Mudersbach, C., Gönnert, G., Gerkensmeir, B., Fröhle, P. and Ujeyl, G., 2015. “XtremRisK -Integrated flood risk analysis for extreme storm surges at open coasts and in estuaries: Methodology, key results and lessons learned”, Coastal Engineering Journal, Vol. 57(1), 1540001.</ref>.
Joint probability approaches have been used in the literature to model the pair of extreme wave height, <math>H_s</math>, and peak period, <math>T_p</math> <ref> Repko, A., Van Gelder, P.H.A.J.M., Voortman, H.G. and Vrijling, J.K., 2004. “Bivariate description of offshore wave conditions with physics-based extreme value statistics”, Applied Ocean Research, Vol. 26, 162-170.</ref>, <math>H_s</math> and associated mean period, <math>T_m</math> <ref> Ferreira, J.A. and Guedes Soares, C., 2002. “Modelling bivariate distributions of significant wave height and mean period”, Applied Ocean Research, Vol. 24, 31-45.</ref>, maximum water level (storm surge), <math>S</math> and associated fullness, <math>F</math>, of the entire storm surge curve defined as the energetic content of the event within the storm duration (Fig. 6)<ref name=Wahl> Wahl, T., Mudersbach, C. and Jensen, J., 2015. “Statistical assessment of storm surge scenarios within integrated risk analyses”, Coastal Engineering Journal, Elsevier, Vol. 57(1), 1540003.</ref>. Corbella and Stretch<ref> Corbella, A. and Stretch, D.D., 2013. “Simulating a multivariate sea storm using Archimedean copulas”, Coastal Engineering, Vol. 76, 68–78.</ref> investigate dependencies between wave height, wave period, storm duration, water level and storm inter-arrival time and use trivariate [https://en.wikipedia.org/wiki/Copula_(statistics) copulas] to jointly analyze the variables that are significantly associated.
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==Extreme storms in coastal engineering practice==

[[Image:PrinosFig7.jpg|thumb|400px|right|Fig. 7. Failure region and joint exceedance probability of a bivariate pair of variables x, y<ref name=Yeh> Yeh, S-P., Ou, S-H., Doong, D-J., Kao, C.C. and Hsieh, D.W.J., 2006. “Joint probability analysis of waves and water level during typhoons”, Proc 3rd Chinese-German Joint Symposium on Coastal and Ocean Engineering.</ref>.]]

[[Image:PrinosFig8.jpg|thumb|500px|right|Fig. 8. Estimation of the worst case combination of <math>H_s</math> and storm surge with a joint return period of 4000 years for a design overtopping discharge <math>Q=0.002 \; m^3/sm</math> of a seawall at the Dutch coast. The wave period for the resulting failure condition is <math>T=8.4 \; s</math> <ref> Galiatsatou, P. and Prinos, P., 2011. “Bivariate Analysis of Extreme Wave and Storm Surge Events. Determining the Failure Area of Structures”, The Open Journal of Ocean Engineering, Vol. 4(1), 4-13.</ref>.]]

Extreme storms are usually related to cross-shore profile changes and longshore changes of the coastline and are considered to induce a range of hazards to coastal areas, the most common of which are flooding and coastal erosion. Population growth, concentration of economic activities, asset concentration, urbanization and tourism lead to an increasing vulnerability of such areas to the aforementioned hazards. The above mentioned challenges coupled with the general inception of a changing climate, with extreme marine events of higher intensity and frequency and mean sea level rise are expected to increase exposure of coastal societies to the associated hazards. Especially when coastal environments are highly urbanised or developed, extreme storm events can induce serious impacts on infrastructure, coastal communities and recreational activities of the affected coastal areas. The increasing potential to predict or forecast such events and to attain reliable estimates of future severe sea states can significantly contribute to reduce flooding and/or erosion risks by prevention or preparedness of the risk receptors.

Extreme storms are also used in the design of coastal protection works, port and harbour structures. Return levels of wave height, wave period, wave run-up and storm surge corresponding to defined return periods (complying with the design standards of each country) are utilised to provide design values of crest characteristics, berm height and width, mean nominal diameter of armour elements and windward slope angle of such structures. They are also used to define the number of layers of coastal structures, to select the appropriate types of armour units, as well as to provide design estimates of toe protection characteristics. During the last few years, probabilistic design approaches based on reliability and risk-based design concepts have been increasingly proposed and applied in the fields of civil engineering and water defences, because of their ability to provide an explicit measure of the safety level of structured systems. More specifically, safety assessments of flood defence assets are increasingly performed with the technique of structural reliability.
Reliability-based design optimization deals with obtaining optimal designs characterized by low costs and by a low probability of failure<ref> Dai Viet, N., Verhagen, H.J., van Gelder, P.H.A.J.M. and Vrijling, J.K., 2008. “Conceptual design for the breakwater system of the south of Doson Naval Base: Optimization versus deterministic design”, Proc. COPEDEC VII, Dubai, UAE, Paper No:053</ref><ref> Van Gelder, P., Buijs, F., Horst, W., Kanning, W., Mai Van, C., Rajabalinejad, M., de Boer, E., Gupta, S., Shams, R., van Erp, N., Gouldby, B.P., Kingston, G., Sayers, P.B., Willis, M., Kortenhaus, A. and Lambrecht, H.J., 2009. “Reliability analysis of flood defence structures and systems in Europe”, Flood Risk Management: Research and Practice-Samuels et al. (eds), Taylor & Francis Group, London, ISBN 978-0-415-48507-4.</ref>. Risk-based design of structures is defined as the approach in which the costs of protection are explicitly weighted against the risk reduction in the protected area. In contrast with reliability-based design, the failure probability for which the structure is designed depends on the consequences of failure<ref> Mai Van, C., van Gelder, P. H. A. J. M. and Vrijling, J. K., 2010. “Risk based design of coastal flood defences-A vietnam case”, In: Reliability, Risk and Safety: Theory and Applications – Briš, Guedes Soares & Martorell (eds), Taylor & Francis Group, London, ISBN 978-0-415-55509-8</ref><ref>Voortman, H. G., 2002. “Risk-based design of large scale flood defence systems”, PhD thesis. Delft University of Technology, the Netherlands. </ref>. To determine the failure probability of a structure is critical for both methods. When the source of the failure consists of a single variable, i.e. extreme wave height or extreme sea level, the failure probability <ref name=Yeh> </ref> can be computed from a distribution function by a given value of the source variable (failure condition). When the source of failure consists of more than one variables, their joint exceedance probability is determined by integrating the joint probability density of the variables over the failure region (Fig. 7).

Failure probability referring to the occurrence of a particular response (i.e. overtopping, force on the structure) can be obtained by intersecting the equal response curve with the joint exceedance probability curve of a certain joint return period. The intersection point is referred to as the worst case loading combination (critical condition) for the response under study. The area within the response curve represents the failure probability of the structure for this particular response (Fig. 8).

==Related articles==
:[[Vulnerability and risk]]
:[[Risk and coastal zone policy: example from the Netherlands]]
:[[Wave climate classification according to wind climate]]
:[[Flood risk analysis study at the German Bight Coast]]
:[[Stability of rubble mound breakwaters and shore revetments]]
:[[Statistical description of wave parameters]]
:[[Wave collision on a vertical wall]]

==References – Further reading==
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{| style="border:1px solid #abd5f5; background:#f1f5fc; margin:0em 0em 0em 5em;"
|<center>The main authors of this article are [https://marineinfo.org/imis?module=person&persid=11179 Panayotis Prinos] and [https://marineinfo.org/imis?module=person&persid=11111 Panagiota Galiatsatou]
</center>

[[Category:Coastal protection]]
[[Category:Hard structures]]
[[Category:Physical coastal and marine processes]]
[[Category:Hydrodynamics]]

Ecosystem services

2026-11-10T12:00:49Z

Admin: Text replacement - "http://www.coastalwiki.org/imis/imis.php?module=person&persid=" to "https://marineinfo.org/imis?module=person&persid="

{{Definition|title=Ecosystem services
|definition= Ecosystem services are benefits people obtain from ecosystems (Millennium Assessment Report (2005)<ref name=M> Millennium Ecosystem Assessment (2005): Ecosystems and Human Well-Being: Synthesis. Washington, DC: Island Press </ref>. }}

An older paper on Ecosystem services can be found on the Discussion page.

==Introduction==

Ecosystem services are usually classified into provisioning, regulating and cultural services (see [[#Classification|Classification]]). Provisioning services include tangible products from ecosystems that humans make use of, such as agricultural crops, timber, fish and seafood or fresh water. Regulating services are the benefits people obtain due to the regulation of natural processes such as water purification and erosion control. Cultural ecosystem services refer to the intangible benefits people receive from ecosystems in form of non-material spiritual, religious, inspirational and educational experience <ref name=K>Kandziora, M., Burkhard, B. and Müller, F. (2013): Interactions of Ecosystem Properties, Ecosystem Integrity and Ecosystem Service Indicators - A Theoretical Matrix Exercise. Ecological Indicators 28 (May):54–78</ref>.

==Concept development==

The earliest ideas behind the concept date back until the 1970s. The ecosystem service concept has received high importance since 1997, when two publications came out: Daily (1997) used the concept to emphasize how strongly humans depend on nature <ref>Daily, G. C. (1997): Nature’s Services: Societal Dependence on Natural Ecosystems. Washington, DC: Island Press</ref>, and Constanza (1997) performed an economic valuation, intending to assign a monetary value to all ecosystem services world-wide <ref name=C> Costanza, R., d’Arge, R., de Groot, R., Farber, S., Grasso, M., Hannon, B., Limburg, K., Naeem, S., Oneill, R.V., Paruelo, J., Raskin, R.G., Sutton, P. and van den Belt, M. (1997): The value of the world’s ecosystem services and natural capital. Nature 387 (6630), 253–260</ref>.

Between 2001 and 2005, the Millennium Ecosystem Assessment was conducted, coordinated by the United Nations Environment Program, applying the concept globally<ref name=M></ref>. In 2007, the international study of “The Economics of Ecosystems and Biodiversity” (TEEB) was initiated, an ecosystem service study with a strong economic focus (TEEB 2010)<ref> TEEB (2010): Mainstreaming the Economics of Nature: A Synthesis of the Approach, Conclusions and Recommendations of TEEB. The Economics of Ecosystems & Biodiversity. Geneva: UNEP </ref>. Many countries are currently developing their own national TEEB reports.

An early overview about the development of the ecosystem service concept is given by Haines-Young and Potschin (2010)<ref name=HP10>Haines-Young, R., & Potschin, M. (2010): The links between biodiversity, ecosystem services and human well-being. In D. Raffaelli & C. Frid (eds.), Ecosystem Ecology: A New Synthesis (Ecological Reviews, pp. 110-139). Cambridge: Cambridge University Press</ref>. Moreover, the authors propose a cascade model to describe how ecosystem services provide a link between ecosystem structures and functions on the one hand and human benefits and values on the other hand. More recently, Constanza et al. (2017) summarize current progresses and challenges of the ecosystem service concept in the past two decades<ref name=C17> Costanza, R., de Groot, R., Braat, L., Kubiszewski, I., Fioramonti, L., Sutton, P., Farber, S. and Grasso, M. (2017): Twenty years of ecosystem services: How far have we come and how far do we still need to go? Ecosystem services 28 (2017): 1-16</ref>.

The goods and services approach is a reductionist method, but the benefits arising from marine biodiversity are entirely dependent on the state of the whole ecosystem. The sum of the parts of the system is less than the value of the whole system, and the different goods and services provided are intrinsically connected. Thus, although this classification of services breaks the environment down into specific components, the inter-dependency of these components, and overall value of the environment should be remembered.<ref>Beaumont, N.J., Austen, M.C., Atkins, J.P., Burdon, D., Degraer, S., Dentinho, T.P., Derous, S., Holm, P., Horton, T., van Ierland, E., Marboe, A.H., Starkey, D.J., Townsend, M. and Zarzycki, T. 2007 Identification, definition and quantification of goods
and services provided by marine biodiversity: Implications for the ecosystem approach. Marine Pollution Bulletin 54: 253–265</ref>

==Classification==

Several competing classifications of ecosystem services exist. Both the classification used by the Millennium Ecosystem Assessment (2005) and the adapted classification used by TEEB (2010) distinguish between the four classes of supporting (or habitat) services, provisioning services, regulating services and cultural services. In contrast, some newer classifications only include the last three categories <ref name=K></ref><ref name=HP>Haines-Young, R. and Potschin, M. (2013): Common International Classification of Ecosystem Services (CICES): Consultation on Version 4, August-December 2012. EEA Framework Contract No EEA/IEA/09/003. Copenhagen: EEA</ref>.

Supporting services can be defined as the basic ecosystem processes, structures and functions that are necessary for the provision of the other ecosystem services; they only have an indirect impact on human well-being<ref name=C17></ref> They are also referred to as “intermediate services”, in contrast to provisioning, regulating and cultural services which form the group of “final services”. This distinction is especially important to avoid double-counting in the context of ecosystem service valuation studies<ref> UNEP-WCMC (2011): Marine and coastal ecosystem services: Valuation methods and their application. UNEP-WCMC Biodiversity Series No. 33. Cambridge: UNEP-WCMC </ref>.

The Common International Classification of Ecosystem Services (CICES), is an ongoing effort to standardize classification issues, focuses only on final services <ref name=HP></ref>. The current version is available for download at https://cices.eu/. Another classification distinguishing between provisioning, regulating and cultural services is the Kiel Classification which was proposed by Kandziora et al. (2013) <ref name=K></ref> and Burkhard et al. (2014) <ref name=B14> Burkhard, B., Kandziora, M., Hou, Y. and Müller, F. (2014): Ecosystem Service Potentials, Flows and Demands – Concepts for Spatial Localisation, Indication and Quantification. Landscape Online 34: 1–32</ref>. This classification has been frequently applied to ecosystem service mapping studies globally, which are based on the so-called matrix approach <ref name=B14> </ref>.

{| style="border-collapse:collapse;background:ivory;" cellpadding=5px align=center width=100%
|+ Table 1: Regulating ecosystem services (adapted from Kandziora et al. 2013<ref name=K></ref>).
|- style="font-weight:bold; text-align:center; background:lightgrey"
! width=20% style=" border:1px solid gray;"| Regulating service
! width=80% style=" border:1px solid gray;"| Definition
|-
| style="border:1px solid gray;"|
| style="border:1px solid gray;"|
|-
| style="border:1px solid gray;"| Global Climate Regulation
| style="border:1px solid gray;"| Long-term storage of greenhouse gases in ecosystems
|-
| style="border:1px solid gray;"| Local climate regulation
| style="border:1px solid gray;"| Changes in local climate components like wind, precipitation, temperature, radiation due to ecosystem properties
|-
| style="border:1px solid gray;"| Air quality regulation
| style="border:1px solid gray;"| Capturing/filtering of dust, chemicals and gases
|-
| style="border:1px solid gray;"| Water flow regulation
| style="border:1px solid gray;"| Maintaining of water cycle features (e.g. water storage and buffer, natural drainage, irrigation and drought prevention)
|-
| style="border:1px solid gray;"| Water purification
| style="border:1px solid gray;"| The capacity of an ecosystem to purify water, e.g. from sediments, pesticides, disease-causing microbes and pathogens
|-
| style="border:1px solid gray;"| Nutrient regulation
| style="border:1px solid gray;"| The capacity of an ecosystem to recycle nutrients, e.g. N, P
|-
| style="border:1px solid gray;"| Erosion regulation
| style="border:1px solid gray;"| Soil retention and the capacity to prevent and mitigate soil erosion and landslides
|-
| style="border:1px solid gray;"| Natural hazard protection
| style="border:1px solid gray;"| Protection and mitigation of floods, storms (hurricanes, typhoons…), fires and avalanches
|-
| style="border:1px solid gray;"| Pollination
| style="border:1px solid gray;"| Bees, birds, bats, moths, flies, wind, non-flying animals contribute to the dispersal of seeds and the reproduction of lots of plants
|-
| style="border:1px solid gray;"| Pest and disease control
| style="border:1px solid gray;"| The capacity of an ecosystem to control pests and diseases due to genetic variations of plants and animals making them less disease-prone and by actions of predators and parasites
|-
| style="border:1px solid gray;"| Regulation of waste
| style="border:1px solid gray;"| The capacity of an ecosystem to filter and decompose organic material in water and soils
|}

{| style="border-collapse:collapse;background:ivory;" cellpadding=5px align=center width=100%
|+ Table 2: Provisioning ecosystem services (adapted from Kandziora et al. 2013<ref name=K></ref>).
|- style="font-weight:bold; text-align:center; background:lightgrey"
! width=20% style=" border:1px solid gray;"| Provisioning Service
! width=80% style=" border:1px solid gray;"| Definition
|-
| style="border:1px solid gray;"|
| style="border:1px solid gray;"|
|-
| style="border:1px solid gray;"| Crops
| style="border:1px solid gray;"| Cultivation of edible plants and harvest of these plants on agricultural fields and gardens which are used for human nutrition
|-
| style="border:1px solid gray;"| Biomass for energy
| style="border:1px solid gray;"| Plants used for energy conversion (e.g. sugar cane, maize)
|-
| style="border:1px solid gray;"| Fodder
| style="border:1px solid gray;"| Cultivation and harvest of fodder for domestic animals
|-
| style="border:1px solid gray;"| Livestock (domestic)
| style="border:1px solid gray;"| Production and utilization of domestic animals for nutrition and use of related products (e.g. dairy, wool)
|-
| style="border:1px solid gray;"| Fibre
| style="border:1px solid gray;"| Cultivation and harvest of natural fibre (e.g. cotton, jute sisal, silk, cellulose) for, e.g. cloths, fabric, paper
|-
| style="border:1px solid gray;"| Timber
| style="border:1px solid gray;"| Wood used for construction purposes
|-
| style="border:1px solid gray;"| Wood fuel
| style="border:1px solid gray;"| Wood used for energy conversion and/or heat production
|-
| style="border:1px solid gray;"| Fish, seafood and edible algae
| style="border:1px solid gray;"| Catch of seafood/algae for food, fish meal and fish oil
|-
| style="border:1px solid gray;"| Aquaculture
| style="border:1px solid gray;"| Harvest of seafood/algae from marine and terrestrial aquaculture farms
|-
| style="border:1px solid gray;"| Wild food, semi-domestic livestock and ornamental resources
| style="border:1px solid gray;"| Harvest of berries, mushrooms, (edible) plants, hunted wild animals, fish catch from recreational fishing, semi-domestic animal husbandry and collection of natural ornaments (e.g. seashells, leaves and twigs for ornamental or religious purposes)
|-
| style="border:1px solid gray;"| Biochemicals and medicine
| style="border:1px solid gray;"| Natural products used as biochemicals, medicine and/or cosmetics
|-
| style="border:1px solid gray;"| Freshwater
| style="border:1px solid gray;"| Used freshwater (e.g. for drinking, domestic use, industrial use, irrigation)
|-
| style="border:1px solid gray;"| Mineral resources
| style="border:1px solid gray;"| Minerals excavated close from surface or above surface (e.g. sand for construction, lignite, gold)
|-
| style="border:1px solid gray;"| Abiotic energy sources
| style="border:1px solid gray;"| Sources used for energy conversion (e.g. solar power, wind power, water power and geothermic power)
|}

{| style="border-collapse:collapse;background:ivory;" cellpadding=5px align=center width=100%
|+ Table 3: Cultural ecosystem services (adapted from Kandziora et al. 2013<ref name=K></ref>).
|- style="font-weight:bold; text-align:center; background:lightgrey"
! width=20% style=" border:1px solid gray;"| Cultural Service
! width=80% style=" border:1px solid gray;"| Definition
|-
| style="border:1px solid gray;"|
| style="border:1px solid gray;"|
|-
| style="border:1px solid gray;"| Recreation and tourism
| style="border:1px solid gray;"| Outdoor activities and tourism relating to the local environment or landscape, including forms of sports, leisure and outdoor pursuit
|-
| style="border:1px solid gray;"| Landscape aesthetic, amenity and inspiration
| style="border:1px solid gray;"| Visual quality of the landscape/ecosystems or parts of them which influences human well-being and the need to create something, esp. in art, music and literature. The sense of beauty people obtain from looking at landscapes/ecosystems as ecosystems provide a rich source of inspiration for art, folklore, national symbols, architecture, advertising and technology
|-
| style="border:1px solid gray;"| Knowledge systems
| style="border:1px solid gray;"| Environmental education based on ecosystem/landscape, i.e. out of a formal schools context, and knowledge in terms of traditional knowledge and specialist expertise arising from living in this particular environment
|-
| style="border:1px solid gray;"| Religious and spiritual
experience
| style="border:1px solid gray;"| Spiritual or emotional values that people or religions attach to local environments or landscapes due to religious and/or spiritual experience
|-
| style="border:1px solid gray;"| Cultural heritage and cultural diversity
| style="border:1px solid gray;"| Values that humans place on the maintenance of historically important (cultural) landscapes and forms of land use (cultural heritage)
|-
| style="border:1px solid gray;"| Natural heritage and natural diversity
| style="border:1px solid gray;"| The existence value of nature and species themselves, beyond economic or human benefits
|}

==Potentials vs. flows==

Ecosystem services do not exist if there is no human need for them<ref name=HP10></ref>. While some regulating services such as carbon sequestration do not require people in the immediate vicinity in order to be considered a benefit, a number of provisioning and cultural services do. For example, a lagoon ecosystem might have all the necessary ecosystem structures and functions (vegetation type and growth function) to provide the ecosystem service of “edible algae”. However, if no people pick and consume the algae, nobody benefits, hence no actual provisioning service was provided.

For practical applications, it is therefore useful to distinguish between ecosystem service potentials and flows. Ecosystem service '''potentials''' are defined as the hypothetical maximum yield of selected ecosystem services<ref name=B14></ref>. In contrast, ecosystem service '''flows''' are defined as the de facto used set (bundles) of ecosystem services and other outputs from natural systems in a particular area within a given time period. In the example above, a large potential for “edible algae” exists, although no flow occurs.

==Supply vs. demand==

Within ecosystem service flows, it is important to distinguish further between ecosystem service supply and demand. According to Burkhard et al. (2012), the '''supply''' are the actually used ecosystem services that are provided by a particular area within a given time period<ref name=B12>Burkhard, B., Kroll, F., Nedkov, S., and Müller, F. (2012): Mapping Ecosystem Service Supply, Demand and Budgets. Ecological Indicators 21: 17–29</ref>. The '''demand''' is the sum of the actually used ecosystem services that are consumed within a particular area within a given time period, no matter where those services originate from<ref name=B12></ref>.

Large differences between local ecosystem service supply and demand might occur<ref name=B12></ref>. For example, the ecosystem service demand for “agricultural crops” and “air quality regulation” within an urban environment might be very high. Food crops are likely to be imported from other regions where a high supply exists. The demand for air quality regulation, however, has to be met in the same locality, or air quality will deteriorate.

==Mapping and assessment==

In an attempt to incorporate ecosystem services in decision making processes, they must be mapped and/or assessed. Because ecosystems are endlessly changing, assessments of ecosystem services should represent aspects of change, incorporating forward-looking perspectives on how ecosystem services might change in the future (Carpenter and Folke 2006<ref>Carpenter, S.R. and Folke, C. 2006. Ecology for transformation. TRENDS in Ecology and Evolution 21: 309-315</ref>). Mapping and assessing ecosystem services is a core component of the European Union Biodiversity Strategy for 2020. There are a number of different ways to go about this. For example, ESMERALDA ([http://www.esmeralda-project.eu/ Enhancing ecoSysteM sERvices mApping for poLicy and Decision mAking]) is a project that aims to provide a coherent methodology for European assessments. ESMERALDA incorporates existing ecosystem services projects and databases such as the working group MAES (Mapping and Assessment of Ecosystem Services) which has created an analytical framework when mapping/assessing ecosystem services for consistency throughout the EU (Biodiversity Information System for Europe) <ref> Biodiversity Information System for Europe. (n.d.). Mapping and Assessment of Ecosystems and their Services (MAES) — Biodiversity Information system for Europe. Retrieved December 13, 2017, from http://biodiversity.europa.eu/maes</ref>.

===Mapping and Assessment Methods===

Ecosystem services can be assessed and mapped using biophysical, economic, or social methods. In '''indicator-based''' ecosystem services assessments, specific indicators or groups of indicators are used to evaluate the state of ecosystem services. These indicators must be measurable, sensitive and specific, as well as relevant to the study site. Information of the suitability of typical ecosystem services indicators for marine applications is provided by Hattam et al. (2014)<ref name=H> Hattam, C., Atkins, J.P., Beaumont, N., Bӧrger, T., Bӧhnke-Henrichs, A., Burdon, D., de Groot, R., Hoefnagel, E., Nunes, P.A., Piwowarczyk, J. and Sastre, S. (2015). Marine ecosystem services: linking indicators to their classification. Ecological Indicators 49: 61-75</ref>.

'''Biophysical''' ecosystem services assessment methods quantify in biophysical units with indicators such as timber stock, crop yield, area of floodplains or nitrogen removal. These can be measured directly, indirectly or through models such as spatial proxy models or process-based models. Flood protection for example could be measured directly through site observations, it could be measured indirectly through aerial photographs and remote sensing, or it could be analyzed based on a water transport model<ref name=B17> Burkhard, B. and Maes, J. (eds.) (2017): Mapping Ecosystem Services. Sofia: Pensoft Publishers.</ref>.

'''Economic methods''' include using market prices for assessments, usually done for provisioning services. [[Contingent Valuation Method|Contingent valuation methods]], [[travel cost method]]s, or damage cost avoided/replacement cost, among many others, are also used<ref name=B17></ref>. Many economic methods use monetary terms (see [[#Monetary vs. non-monetary valuation|Monetary vs. non-monetary valuation]]).

'''Social methods''' of ecosystem service assessments include methods such as participatory mapping, where stakeholders are involved to map ecosystem services according to their perceptions. Preference assessment, scenario planning and photo-elicitation surveys can also be used<ref name=B17></ref>.

Using '''maps''' to display ecosystem services can help show ecosystem condition, identify unsustainable practices and risk areas, assess synergies and trade-offs between ecosystem services and highlight possible discrepancies between ecosystem services supply and demand. By mapping ecosystem services, regions can be compared and ecosystem services hotspots and coldspots can be delineated. One example is the expert-based matrix approach, which can be used for instance to map ecosystem services potentials based on land use/land cover data<ref name=B14></ref><ref name=B17></ref>.

There are a number of difficulties that must be overcome when mapping ecosystem services. Coastal and marine ecosystem services in particular are complex to map due to their three dimensional nature, as ecosystem services can change with depth <ref name=B17></ref>. Practical guidelines and more information can be found, e.g. in Burkhard & Maes’s (2017) textbook called “Mapping Ecosystem Services”.

==Monetary vs. non-monetary valuation==

Ecosystem services can be valued using monetary or non-monetary techniques. Monetary methods in the past have been more common<ref name=S> Scholte, S. S., van Teeffelen, A. J. and Verburg, P. H. (2015): Integrating socio-cultural perspectives into ecosystem service valuation: a review of concepts and methods. Ecological economics 114: 67-78</ref>, as this allows for ecosystem services to be included in traditional cost-benefit assessments and can help policy makers realize important decisions<ref> Torres, C. and Hanley, N. (2017): Communicating research on the economic valuation of coastal and marine ecosystem services. Marine Policy 75, 99-107</ref>. Some problems that can arise when using monetary valuation for ecosystem services include problems with spatial and temporal scale, as well as the nonlinearity of ecosystem services. Furthermore, while monetary valuation allows for standardizations that can easily be taken over in cost-benefit-analysis, the use of monetary valuation for assessing ecosystem services can neglect other social perspectives on the importance of ecosystems on human wellbeing<ref name=S></ref>. Monetary valuation can downplay intrinsic, symbolic and other non-economic values and is especially inadequate at valuing most non-use services<ref> Fanny, B., Nicolas, D., Sander, J., Erik, G. B., & Marc, D. (2015): How (not) to perform ecosystem service valuations: pricing gorillas in the mist. Biodiversity and conservation 24(1): 187-197</ref>.

==Coastal and marine applications==

The importance of coastal and marine ecosystems for ecosystem services provision has long been recognized<ref name=C></ref>. While provisioning services such as fish provide income for many coastal communities, natural coastal environments also provide a variety of highly important regulating services such as flood protection and water purification<ref name=B11> Barbier, E. B., Hacker, S. D., Kennedy, C., Koch, E. W., Stier, A. C. and Silliman, B. R. (2011): The value of estuarine and coastal ecosystem services. Ecological monographs 81(2): 169-193</ref>.

However, anthropological influences on coastal and marine ecosystems have been increasing. While coastal areas only account for 4% of the total land cover, they account for a third of the Earth’s population<ref name=Ba17> Barbier, E. B. (2017). Marine ecosystem services. Current Biology 27(11): R507-R510</ref>. As such, these areas are some of the most exploited in the world. Marine environments are under pressure from overfishing, increased traffic, pollution and hypoxia, while climate change and sea level rise pose additional impacts <ref name=Ba17></ref>.

Although research on ecosystem services in general is currently growing exponentially, there are still significant knowledge gaps regarding marine and coastal ecosystem services <ref name=L> Liquete, C., Piroddi, C., Drakou, E. G., Gurney, L., Katsanevakis, S., Charef, A. and Egoh, B. (2013): Current status and future prospects for the assessment of marine and coastal ecosystem services: a systematic review. PloS one 8(7), e67737</ref>. The current state of research and typical challenges regarding marine and coastal ecosystem services has been summarized by Barbier (2011) <ref name=B11></ref> and Liquete et al. (2013) <ref name=L></ref>. Böhnke-Henrichs et al. (2013) <ref> Böhnke-Henrichs, A., Baulcomb, C., Koss, R., Hussain, S. S., & de Groot, R. S. (2013). Typology and indicators of ecosystem services for marine spatial planning and management. Journal of Environmental Management 130: 135-145</ref> and Hattam et al. (2015) <ref name=H></ref> have assessed ecosystem services indicators that can be used specifically in marine contexts. Existing research in the field of coastal and marine cultural ecosystem services has been reviewed by Martin et al. (2016) <ref> Martin, C. L., Momtaz, S., Gaston, T. and Moltschaniwskyj, N. A. (2016): A systematic quantitative review of coastal and marine cultural ecosystem services: Current status and future research. Marine Policy 74: 25-32</ref> and Rodrigues et al. (2017) <ref> Rodrigues, J. G.,Conides, A.J., Rodriguez, S.R., Raicevich,S., Pita, P., Kleisner, K.M., Pita, C., Lopes, P.F.M., Roldán, V.A., Ramos, S.S., Klaoudatos, D., Outeiro, L., Armstrong, C., Teneva, L., Stefanski, S., Böhnke-Henrichs, A., Kruse, M., Lillebø, A.I., Bennett, E.M., Belgrano, A., Murillas, A., Pinto, I.S., Burkhard, B. and Villasante, S. (2017): Marine and Coastal Cultural Ecosystem Services: knowledge gaps and research priorities. One Ecosystem 2: e12290</ref>.

Regarding practical applications, ecosystem service assessments have a high potential to support decision making even in complex coastal systems. Application frameworks or case studies of ecosystem services assessments in the field of coastal management can be found in the publications by Granek et al. (2010) <ref> Granek, E.F., Polasky, S., Kappel, C.V., Reed, D.J., Stoms, D.M., Koch, E.W., Kennedy, C.J., Cramer, L.A., Hacker, S.D., Barbier, E.B. and Aswani, S. (2010): Ecosystem services as a common language for coastal ecosystem‐based management. Conservation Biology 24(1): 207-216</ref>, Luisetti et al. (2014) <ref> Luisetti, T., Turner, R.K., Jickells, T., Andrews, J., Elliott, M., Schaafsma, M., Beaumont, N., Malcolm, S., Burdon, D., Adams, C. and Watts, W. (2014): Coastal Zone Ecosystem Services: From science to values and decision making; a case study. Science of the Total Environment 493: 682-693</ref> and de Juan et al. (2017) <ref> De Juan, S., Gelcich, S. and Fernandez, M. (2017): Integrating stakeholder perceptions and preferences on ecosystem services in the management of coastal areas. Ocean & Coastal Management 136: 38-48</ref>. One example for a large-scale application of the concept with a high relevance for policy-making is the UK National Ecosystem Service Assessment (Turner et al. 2014) <ref>Turner, K., Schaafsma, M., Elliot, M., Burdon, D., Atkins, J., Jickells, T. and Tett, P. (2014): UK national ecosystem assessment follow-on. Work package report 4: Coastal and marine ecosystem services: principles and practice. UK: UNEP-WCMC, LWEC</ref>.

==Related articles==
:[[Multifunctionality and Valuation in coastal zones: concepts, approaches, tools and case studies]]
:[[Multifunctionality and Valuation in coastal zones: introduction]]
:[[Values of amenities in coastal zones]]
:[[Socio-economic evaluation]]

==External link==
[https://www.unep-wcmc.org/resources-and-data/marine-and-coastal-ecosystem-services Introduction to Marine and Coastal Ecosystem Services]

==References==
<references/>

<div style = "float: center"> <div align="center">
{| style="border:1px solid #abd5f5; background:#f1f5fc; margin:0em 0em 0em 5em;"
|<center>The main authors of this article are [https://marineinfo.org/imis?module=person&persid=35372 Simone Krüger] , [https://marineinfo.org/imis?module=person&persid=35375 Meike Wege] and
[https://marineinfo.org/imis?module=person&persid=35376 Marion Kruse] </center>
|}

[[Category:Coastal and marine ecosystems]]
[[Category:Integrated coastal zone management]]
[[Category:Evaluation and assessment in coastal management]]
[[Category: MarBEF Wiki]]

Coastal Wiki Editorial Board

2026-11-10T12:00:49Z

Admin: Text replacement - "http://www.coastalwiki.org/imis/imis.php?module=person&persid=" to "https://marineinfo.org/imis?module=person&persid="

The members of the Coastal Wiki Editorial board are:

{| border="1" cellspacing="0" cellpadding="4" width="750px" span class="plainlinks wikitable sortable"
|+

!Name
!Expertise
!Affiliation
|-

|[https://marineinfo.org/imis?module=person&persid=49 Berlamont, Jean]
|Coastal Hydrodynamics and Mud dynamics
|[http://www.coastalwiki.org/imis/imis.php?module=institute&insid=2957 KULeuven (BE)]
|-

|[https://marineinfo.org/imis?module=person&persid=12523 Breil, Margaretha]
|Social Sciences
|[http://www.coastalwiki.org/imis/imis.php?module=institute&insid=6804 FEEM (IT)]
|-

|[https://marineinfo.org/imis?module=person&persid=3055 Campostrini, PierPaolo]
|Lagoon Systems / Knowledge Management
|[http://www.coastalwiki.org/imis/imis.php?module=institute&insid=1877 CORILA (IT)]
|-

| [https://marineinfo.org/imis?module=person&persid=11538 Coccossis, Harry]
|Planning
| [http://www.coastalwiki.org/imis/imis.php?module=institute&insid=6629 TUC (GR)]
|-

|[https://marineinfo.org/imis?module=person&persid=10939 Dankers, Norbert]
|Marine Ecology
|[http://www.coastalwiki.org/imis/imis.php?module=institute&insid=5450 Wageningen UR (NL)]
|-

|[https://marineinfo.org/imis?module=person&persid=7574 Doody, Pat]
|Geography / Coastal Management
|[http://www.coastalwiki.org/imis/imis.php?module=institute&insid=4882 NCC (UK)]
|-

|[https://marineinfo.org/imis?module=person&persid=120 Dronkers, Job]
|Coastal Management and Morphodynamics
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Closure depth

2026-11-10T12:00:49Z

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<div style="border:1px solid #000000; text-align:center; align=center; padding=5px ; margin-right:20px; margin-left:20px">
The concept of closure depth refers to sandy shores. It is recommended to read this article in conjunction with the article [[Shoreface profile]].</div>

{{Definition|title=Closure depth (DoC)
|definition= Closure depth is conceived as the offshore limit beyond which cross-shore sediment transport or its net contribution to the coastal sediment balance is negligible for the relevant wave climate and time scale.}}

Two operational proxies are often used in the scientific literature:
#Hallermeier distinguished inner and outer closure depths, which are estimated from wave-induced sediment-mobility criteria (Hallermeier 1981<ref name=H81>Hallermeier, R.J. 1981. A profile zonation for seasonal sand beaches from wave climate. Coastal Engineering 4: 253–277</ref>, 1983<ref name=H83>Hallermeier, R.J. 1983. Sand transport limits in coastal structure design. Proceedings Coastal Structures ’83, American Society of Civil Engineers, pp. 703–716</ref>). Hallermeier’s limits refer to wave-induced seabed activity. They do not include sediment transport generated independently by tidal, wind-driven, density-driven or ocean currents.
#Kraus et al. (1998<ref name=K98>Kraus, N.C., Larson, M. and Wise, R.A. 1998. Depth of closure in beach-fill design. Coastal Engineering Technical Note CETN II-40, 3/98, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.</ref>) estimated closure depth as the cross-shore location beyond which no significant bed-level change is detected in repeated profile surveys over the considered time interval.

Hallermeier interpreted the inner limit as the approximate boundary between the highly active littoral zone (the upper shoreface) and a less active shoal zone (the lower shoreface), and the outer limit as the approximate boundary of the shoal zone, beyond which the annual median wave condition cannot initiate sediment motion.

Kraus et al. assumed that the depth beyond which no detectable bed-level change occurs represents the boundary across which no significant net sediment transport occurs.

Both approaches are therefore indirect proxies for the conceptual closure depth, but neither is based on direct measurement of the net cross-shore sediment flux. The absence of detectable bed-level change does not necessarily imply negligible net sediment transport. Small systematic bed-level changes distributed over the broad lower shoreface can represent substantial sediment volumes, while sediment transport can also occur without local bed-level change if the transport has little spatial divergence<ref name=V19>Valiente, N.G., Masselink, G., Scott, T., Conley, D. and McCarroll, R.J. (2019) Role of waves and tides on depth of closure and potential for headland bypassing. Mar. Geol. 407, 60–75</ref>.

==Relevance of the closure depth concept==
The closure depth is closely related to the concept of '[[active coastal zone]]', which is based on the assumption that wave-induced sedimentary exchange processes between the inner continental shelf and the coast are mainly confined to a coastal strip - the shoreface. For wave-dominated coasts, the outer closure depth is often taken as the seaward boundary of the active coastal zone considered in long-term coastal sediment budgets. The inner closure depth is more relevant to the upper shoreface and shorter-term profile adjustment. Closure depth determines the assumed width and volume of the profile participating in coastal adjustment, see [[Shoreface profile]]. An error in closure depth therefore propagates directly into estimates of nourishment volume and shoreline displacement. Closure depth is a crucial parameter in models for estimating shoreline retreat due sea level rise ([[Bruun rule]]) or shoreline adaptation to changes in the nearshore wave climate resulting from natural causes or human interventions ([[Littoral drift and shoreline modelling|one-line models]]). No unique, generally valid formula for predicting the closure depth has been established so far.

[[File:InnerClosureDepth.jpg|right|thumb|450px|caption |Fig. 1. Schematic illustration of the closure-depth concepts of Hallermeier and Kraus et al. The active coastal zone is represented here by the upper shoreface, where cross-shore sediment exchange occurs frequently over timescales of years to decades. The inner closure depth is located where the mean beach profile converges with the storm profile associated with wave conditions exceeded for approximately 12 hours per year.]]

Sand transport in the coastal zone is mainly driven by waves. However, this only holds within a zone of limited cross-shore width. In deep water, waves and seabed hardly interact, because wave orbital motion decreases exponentially with depth (see [[Shallow-water wave theory]]). The strip along the coast where sand transport is mainly driven by waves is called the [[active coastal zone]]. The closure depth is commonly used as an estimate of the seaward boundary of the active coastal zone for the timescale and processes considered. Wave-induced sand transport has both a longshore and a cross-shore component. The longshore component plays a major role in structural long-term shore accretion (transport convergence) or shore erosion (transport divergence). The cross-shore component is mainly responsible for large seasonal sand transfers up and down the beach, especially by alternating mild weather and storm weather conditions (Fig. 1).

The active coastal zone is a zone of intense morphodynamics: the mutual interaction between wave dynamics and seabed/beach morphology. The influence of nearshore interventions (e.g. jetties, groynes, breakwaters, dredging, dumping) that influence the wave climate will trigger a morphodynamic feedback that will extend across the shoreface, approximately to the closure depth corresponding to the timescale considered. This also holds for the impact of sea level rise. Morphodynamic feedbacks are at the core of the concept of equilibrium shoreface profile. At the annual-decadal time scale (scale of alternating storm and mild weather conditions) morphodynamic activity involves mainly the upper shoreface, the zone of wave transformation, refraction and breaking. At the decadal-centennial time scale sediment exchange between the upper and lower shoreface cannot be ignored. The concept of active coastal zone therefore has a temporal component; the closure depth at shorter timescales is smaller than the closure depth at longer time scales. The shorter timescale and smaller closure depth are most relevant for estimating the impact of storms (see [[Dune erosion]]); the longer timescale and greater closure depth are most relevant for estimating the impact of sea level rise (see the article [[Bruun rule]]).

Process-based models calculate sediment transport throughout the model domain and therefore need not prescribe closure depth as an internal transport boundary. However, their results depend on the offshore extent of the model, boundary conditions and the representation of slow lower-shoreface processes. For regional and long-term studies, simpler models using an assumed closure depth remain widely used because they are computationally more practical.

==Closure depth based on wave-driven sand transport==
Hallermeier (1981<ref name=H81>Hallermeier, R. J. 1981. A Profile Zonation for Seasonal Sand Beaches from Wave Climate. Coastal Engineering. 4: 253-277.</ref>, 1983<ref name=H83>Hallermeier, R. J. 1983. Sand Transport Limits in Coastal Structure Design, Proceedings, Coastal Structures ’83, American Society of Civil Engineers, pp. 703-716.</ref>) defined three profile zones, i.e. a littoral zone, a shoal or buffer zone and an offshore zone or shelf zone. This partition defines two closure depths, namely:
* an “inner” (closer to shore) closure depth <math>h_{in}</math> corresponding to the seaward boundary of the littoral zone, and
* an “outer” or “lower” (further from shore) closure depth <math>h_{out}</math> corresponding to the seaward boundary of the shoal zone.
Hallermeier associated the littoral and shoal zones approximately with what are now commonly called the upper and lower shoreface.

Hallermeier (1981<ref name=H81/>) derived for the inner closure depth the formula

<math>h_{in} = 2.28 H_{12h/y}- 68.5 (\Large\frac{ H_{12h/y}^2}{g T_{12h/y}^2}\normalsize), \qquad (1)</math>

where <math>g</math> is the acceleration of gravity, <math>H_{12h/y}</math> is the significant wave height exceeded for a total of approximately 12 hours in an average year, corresponding to about 0.137% of the time, <math> T_{12h/y}</math> is the wave period associated with these conditions. The wave data should represent the non-breaking wave conditions reaching the shoreface.

The first term in the formula (1) is directly proportional to wave height and is the main contributor to the inner closure depth (Depth of Closure DoC). The second term provides a small correction associated with the wave steepness. Equation (1) can be further generalized to incorporate other time scales by introducing into it a significant wave height exceeded 12 hours in a particular time interval. The theoretical background of the inner DoC <math>h_{in}</math> is based on its relation to the sediment mobility number. Grain size does not appear explicitly in Hallermeier’s inner-limit formula. This empirical result was obtained for fine- to medium-sand conditions (typical sediment diameters, ranging between 0.16 and 0.42 mm) and should not be interpreted as general proof that closure depth is independent of sediment properties<ref name=H78>Hallermeier, R. J. 1978. Uses for a calculated limit depth to beach erosion. Proceedings, 16th Coastal Engineering Conference, American Society of Civil Engineers, pp. 1493 - 1512</ref><ref name=H81/><ref>Royer, E., Wang, P. and Cheng, J. 2023. Determining depth of closure based on time-series beach profiles and empirical formulas: A case study along the Florida coast. Shore & Beach, 91(1): 3-22</ref>.

The outer closure depth <math>h_{out}</math> is the estimated maximum depth beyond which the annual median wave condition cannot initiate motion of the specified bed sediment. For the outer closure depth Hallermeier (1983<ref name=H83/>) derived the formula

<math>h_{out} = 0.018 \,H_s T_s \, \sqrt{\Large\frac{g}{d_{50} (s-1)}\normalsize}, \qquad (2)</math>

where <math>H_s</math> and <math>T_s</math> are the significant wave height and period respectively, <math>d_{50}</math> is the median [[sediment]] diameter and <math>s</math> is the ratio of specific gravity of sand to that of fluid (about 2.65). The outer closure depth <math>h_{out}</math> depends on both hydrodynamic and sedimentological parameters, in contrast with <math>h_{in}</math>. Both closure depths refer to MLW ([[mean low water]]) conditions. Hallermeier considered the estimates (1) and (2) appropriate for exposed microtidal coastal environments with high wave energy and low tidal ranges<ref name=H78/>. Since the outer closure depth Eq. (2) is based on another criterion than the inner closure depth Eq. (1), it may happen that in some cases the inner closure depth is deeper than the outer closure depth<ref name=MF21>McFall, B.C., Brutsche, K.E., Priestas, A.M. and Krafft, D.R. 2021. Evaluation techniques for the beneficial use of dredged sediment placed in the nearshore. J. Waterw. Port Coast. Ocean Eng. 147, 04021016</ref>. Such a result indicates that the two empirical estimates do not form a physically consistent zonation for the local wave and sediment conditions; the formulas should not then be interpreted literally as ordered profile boundaries.

Valiente et al. (2019<ref name=V19/>) define the ‘wave base’ as the outer limit of the lower shoreface and estimate its position from the maximum depth of significant bed activity and sediment transport, termed the Depth of Transport (DoT).

Houston (1995<ref name="Houston 1995">Houston, J. R. 1995. Beach-fill volume required to produce specified dry beach width. Coastal Engineering Technical Note 11-32, U.S. Army Engineer Waterways Experiment Station, Vicksburg, MS.</ref>) simplified Hallermeier’s formulation using properties of a Pierson-Moskowitz wave spectrum (see [[Statistical description of wave parameters]]) and a modified exponential distribution of significant wave height over time to express the DoC in terms of mean annual significant wave height. Following Houston’s approach, the Hallermeier equation can be expressed in the form:

<math>h_{in} = 6.75 \overline {H_{s}} . \qquad (3) </math><br>

Equation (3) has the advantage to incorporate only a single parameter to estimate the closure depth (DoC) without the need to determine the wave height and period exceeded 12 hours in a particular time interval. Houston’s expression is convenient where only annual mean significant wave height is available, but it relies on assumed wave-height statistics. Where a sufficiently long local wave record exists, the 12-hour exceedance condition should be determined directly.<p>
In the original formulation of Hallermeier (1981<ref name=H81/>) and subsequent modifications, the DoC was defined based on the largest wave height exceeded 12 hours per year. This definition incorporates a time element, but the exact event associated with the value of wave height is ambiguous. Depending on changes in storm activity and wave conditions from year to year, the predicted DoC can vary substantially. In order to determine a representative value of the DoC based on this definition, wave conditions averaged over a period of several years must be employed.

Udo et al. (2020<ref>Udo, K., Ranasinghe, R. and Takeda, Y. 2020. An assessment of measured and computed depth of closure around Japan. Sci. Rep. 10, 2987</ref>) tested equations (1) and (2) using observed values for <math>H_{12h/y}</math> and <math>T_{12h/y}</math> at different field sites around Japan where observed profile data were available for at least 5 years. Inner closure depth (DoC) was determined by analysing the envelope of the profile data in a way similar to Kraus et al.<ref name=K98/>. They concluded that the coefficients in equation (1), although providing acceptable estimates, appear to be location dependent, overestimating DoC along the Pacific Ocean side and underestimating DoC along the Sea of Japan side. The empirical coefficients are not universal and should be validated against regional profile observations where available.

A useful extension of calculating the closure depth (DoC) based on average annual wave conditions is to relate the DoC to a particular time period of interest over which specific storm events or seasonal wave conditions occur. A similar “wave-by-wave” interpretation of the DoC was introduced by Kraus and Harikai (1983<ref>Kraus, N. C., and Harikai, S. 1983. Numerical model of the shoreline change at Oarai Beach CoastaI Engineering 7: 1-28.</ref>). In a wave-by-wave or event approach, the DoC can be associated with a ''recurrence frequency'' or return period for a particular storm. The return period should be associated with the wave height, not with the [[storm surge]]. This event-related limit should not automatically be equated with the long-term closure depth, because cumulative sediment response also depends on storm duration, wave period, water level and event sequence.

==Closure depth based on repeated shoreface profile measurements==
The Hallermeier formulas estimate depths associated with specified wave-induced seabed-activity or mobility criteria. Direct measurements of net cross-shore sediment flux at these depths are rarely available, so field comparisons generally use indirect morphological or sedimentological indicators. The closure depth in the field is therefore often related to morphological or sedimentary features:
# a zone of minimum sand accretion or erosion (according to the definition of closure depth)
# a discontinuity of the shoreface slope or a discontinuity in the shoreface sediment composition.

[[Image:OceanCityProfiles.jpg|450px|thumb|right|Fig. 2. Mean profile, envelope and standard deviation of repeated profile elevations at Ocean City, Maryland. The depth is referenced to the National Geodetic Vertical Datum (NGVD).The profile envelope converges near 5.5 m depth, providing a profile-based closure-depth estimate for the four-year survey period. Renewed variability farther offshore occurs over inherited shoals and does not necessarily represent sediment exchange with the present beach. Adapted from Kraus et al. (1998<ref name=K98/>).]]

Kraus et al. (1998<ref name=K98/> proposed that the inner closure depth <math>h_{in}</math> should correspond to the most landward location where the shoreface profiles from repeated measurements converge. The outer closure depth <math>h_{out}</math> should correspond to the location where no significant bed level change is detected from repeated profile measurements. This is illustrated in Fig. 2 showing the result of repeated surveys of a shoreface profile on the US Atlantic coast. The envelope of recorded elevations (above and below the mean) in any profile survey over the 4-year interval of available data and the standard deviation of depths are plotted as functions of the distance offshore. The envelope tends to converge in the depth range of 5 to 6 m for this particular profile, seaward of which the profile elevations separate over the crests of the shoals.
Formation of the offshore shoals can be attributed to earlier coastal and geologic processes and not to offshore movement of sediment from the present beach. The convergence of the envelope landward of the offshore [[shoal]]s indicates that movement of sediment on the shoals is not directly related to sediment exchange on the nearshore profile. For the profile data shown in Fig. 2, corresponding to a 4-year time interval, <math>h_{in}</math> is approximately 5.5 m. The outer depth <math>h_{out}</math> is situated around the 10 m depth contour, where no significant bed level change is observed during the survey period. The Hallermeier formula (1) predicts an inner closure depth <math>h_{in} \approx</math> 6 m, in reasonable agreement with the profile data. Formula (2) gives for the outer closure depth at Ocean City (<math>H_s</math>=1 m, <math>T_s</math> = 6 s, <math>d_{50}</math>=0.3 mm)<ref>Stauble, D.K., Garcia, A.W., Kraus, N.C., Grosskop, W.G. and Bass, G.P. 1993. Beach Nourishment Project Response and Design Evaluation: Ocean City, Maryland Report 1 1988-1992. USACE</ref> a value of about 11 m, also in reasonable agreement.

Barrineau et al. (2021<ref>Barrineau, P., Janmaat, R. and Kana, T. 2021. Empirical depths of closure along the US East coast. Coastal Engineering 170, 104009</ref>) performed a similar study but for a much larger number of transects at different sites along the US East coast. They conclude that the method of Kraus et al. yields estimates for the inner closure depth <math>h_{in}</math> comparable to the results of the Hallermeier formula (1) for wave dominated coastal sections. However, for coastal sections where the energy of tides and waves is of the same order (mixed-energy coasts), the estimates for the closure depth according to the method of Kraus et al. appear to be substantially smaller than the results of the Hallermeier formula (1). The authors also note the influence of coastal inlets on the DoC estimates. Near inlets and on mixed wave–tide coasts, profile change can be strongly influenced by tidal channels, deltas and alongshore redistribution. The Hallermeier wave-only formulas should not be expected to reproduce these patterns.

Birkemeier (1985<ref name ="Birkemeier 1985">Birkemeier, W. A. 1985. Field data on seaward limit of profile change. Journal of Waterway, Port, Coastal and Ocean Engineering 111(3): 598-602.</ref>) compared Eq. (1) with observations over a 16-months period of coastal profiles on the Pacific Ocean and the Gulf of Mexico. He concluded that Eq. (1) overpredicts the closure depth derived from these data and proposed a modified version based on the profile-convergence proxy:

<math>h_{in} = 1.75 H_{12h/y}- 57.9 (\Large\frac{ H_{12h/y}^2}{g T_{12h/y}^2}\normalsize). \qquad (4)</math>

It produces a smaller estimate of the depth of closure than the Hallermeier equation (1) for given wave conditions.

==Other methods for closure depth estimation==
Aragones et al. (2018<ref>Aragonés, L., Ignacio Pagán, J., López, I. and Serra, J.C. 2018. Depth of closure: New calculation method based on sediment data. Int. J. Sediment Res. 33: 198–207</ref>) derived depth of closure estimates by analysing trend changes in the grain size distribution of several coastal profiles of the Mediterranean coast near Valencia. They argued that the DoC is situated at a certain depth where the tendency of seaward decreasing grain size <math>d_{50}</math> changes into an increasing trend before decreasing further offshore again. At the studied Mediterranean sites, a change in the cross-shore grain-size trend coincided with the profile-convergence depth. Whether this indicator applies elsewhere depends on local sediment sources, sorting processes and inherited stratigraphy. However, the depth was substantially smaller than the closure depth predicted by Hallermeier's formula (1) and also smaller than predicted by the formula (4) of Birkemeier.

McFall et al. (2021<ref name=MF21>McFall, B.C., Brutsche, K.E., Priestas, A.M. and Krafft, D.R. 2021. Evaluation techniques for the beneficial use of dredged sediment placed in the nearshore. J. Waterw. Port Coast. Ocean Eng. 147, 04021016</ref>) compiled data on the stability of dredged sediment deposits placed on the shoreface for 20 sites along with the Atlantic and Pacific US coasts. Nearshore placements landward of the inner limit Eq. (1) were generally mobile, whereas placements near or beyond the outer limit Eq. (2) were substantially more stable. The closure-depth formulas can therefore assist preliminary siting, although local currents and morphology must also be considered.

==Limitation of the closure depth concept==
The wave-induced seabed-activity criteria underlying the Hallermeier formulas (1) and (2) do not necessarily correspond to the criterion of (almost) zero depth profile change. Zero depth profile change may arise, for example, in the situation where depth change due to sediment transport across the DoC contour derived from profile data is compensated by accretion or erosion due to gradients in longshore sediment transport<ref name=AA>Anthony, E.J. and Aagaard, T. 2020. The lower shoreface: Morphodynamics and sediment connectivity with the upper shoreface and beach. Earth-Science Reviews 210, 103334</ref>. Another issue is that depth change of the lower shoreface which is below the detection limit can amount to a considerable sediment flux when integrated over the whole lower shoreface <ref name=V19/>. A mean change of only 1 cm over a lower shoreface 2 km wide represents 20 m<sup>3</sup> of sediment per meter of shoreline. Insight into the local coastal dynamics is therefore required when applying the closure depth concept.

The Hallermeier formulas are based on the assumption that sediment transport on the shoreface is dominated by wave action and that the contribution of other drivers of sediment transport can be ignored. This may be a reasonable assumption for many shores, especially exposed microtidal coasts. However, it cannot be expected that the Hallermeier formulas are applicable in situations where this is not the case. Examples are: (1) macrotidal coasts, where combined wave- and tide-driven sediment transport across the DoC contour can be much larger than sediment transport driven only by waves<ref name=V19>Valiente, N.G., Masselink, G., Scott, T., Conley, D. and McCarroll, R.J. (2019) Role of waves and tides on depth of closure and potential for headland bypassing. Mar. Geol. 407, 60–75</ref>; (2) coasts where important sediment transport across the shoreface result from up- and downwelling currents induced by wind stress and density gradients<ref name=AA/>.
In some situations the determination of wave characteristics on the lower shoreface may not be straightforward. Valiente et al. (2019<ref name=V19/>) observed that on the macrotidal, embayed and high-energy coastline of SW England, offshore wave conditions do not well represent wave conditions at the toe of the lower shoreface due to the presence of rocky headlands. Wave conditions representative of the local shoreface should therefore be used, not untransformed offshore buoy data where refraction, sheltering or depth limitation is important.

Hartman and Kennedy (2016<ref>Hartman, M. and Kennedy, A.B. 2016. Depth of closure over large regions using airborne bathymetric lidar. Marine Geology 379: 52–63</ref>) argue that considering only the annual 12h extreme conditions for the inner DoC ignores the potential impact of more frequent less severe storm conditions. This can be important in tropical regions where cyclones generate extreme waves, but with such short durations that they have little opportunity to move large amounts of sediment.

==Conclusion==
Closure-depth estimates depend on the criterion and method used. A depth inferred from detectable profile change is not necessarily equivalent to one calculated from sediment-mobility or wave-statistical criteria. Closure depth can also vary alongshore and change over time as wave conditions, tidal currents, sediment characteristics or shoreface morphology change. It should therefore be treated as an uncertain model parameter rather than as a precisely known and fixed contour<ref>Durkin, C.J., Seenath, A. and Knaapen, M.A.F. 2025. A critical review of closure depth theories and uncertainties: implications for shoreline modelling and coastal management. Ocean and Coastal Management 267, 107732</ref>. Reported values should specify the estimation method, reference water level, observation period and detection threshold. Where closure depth strongly influences a shoreline prediction, calculations should preferably be repeated for a plausible range of values.

==Related articles==
:[[Shoreface profile]]
:[[Active coastal zone]]
:[[Bruun rule]]
:[[Littoral drift and shoreline modelling]]

==References==
<references/>

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|<center>The main author of this article is [https://marineinfo.org/imis?module=person&persid=11184 Grzegorz, Rozynski]<br></center>
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[[Category:Articles by Grzegorz, Rozynski]]
[[Category:Coastal protection]]
[[Category:Physical coastal and marine processes]]
[[Category:Beaches]]
[[Category:Morphodynamics]]

Artificial reefs

2026-11-10T12:00:49Z

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{{Review
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{{Review
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==Introduction==
An '''artificial reef''' (AR) can be defined as any solid man-made structure which has been submerged in the natural environment (Bohnsack, 1989<ref>Bohnsack, J.A., 1989. Are high densities of fishes at artificial reefs the result of habitat limitation or behavioral preference? ''Bulletin of Marine Science''. '''44''', 631-645.</ref>). Artificial reefs are often also called '''low-crested structures (LCS)'''. They may be purposely placed to alter local hydrodynamics (coastal defense ARs) or this effect may be incidental (ship wrecks, offshore windmills, oil rigs etc.). Regardless of their construction or purpose, artificial reefs generally involve the introduction of a hard substrate to a soft bottom environment, altering both the abiotic as the biotic properties of the environment. Coastal defense artificial reefs are therefore often constructed as multipurpose structures, i.e. besides the main function to defend the coast from erosion they also maximise secondary objectives such as to improve spot surfability, to stabilize nourishment material and to create marine parks of increased [[biodiversity]]. Since different aims, materials and configurations as well as site dependent factors are to be considered, design criteria for these structures are not easily defined a priori.

==Materials==
===Stones===
Stones are especially used for rubble mound structures whose hydraulic stability is verified through the formulae available in literature for low-crested structures (Burcharth et al., 2007 <ref>Burcharth, H. F., Hawkins, S., Zanuttigh, B., and Lamberti, A., 2007. ''Environmental Design Guidelines for Low Crested Coastal Defence Structures'', Elsevier.</ref>). Un-corrected design of the structure by a wrong selection of stone size causes a low efficiency of the AR. Structure reshaping induced by wave breaking over the reef may occur and produce instability, with stones rolling down from the structure. Stones are relatively cheaper than other materials but can be more dangerous for surfing safety. For more detailed information, see [[Stability of rubble mound breakwaters and shore revetments]].

===Geobags, geotextile sand containers and geotubes===
Geotubes consist of sacks made by geotextile that are filled with sand or gravel. They are characterized by a length and diameter of 20 and 3 m respectively and are particularly recommended for deep bottoms (Matteotti et al., 2003<ref>Matteotti G., Ruol P., 2003. L’impiego dei geosintetici nelle opere di ingegneria marittima e costiera, 2003 [https://pdfslide.net/documents/matteotti-ruol-geosintetici.html]</ref>). Geotextile sand containers (GSCs) and geobags are very similar to geotubes, although their dimensions are smaller than that and thus are usually adopted at lower depths. The cost of a reef made of GSCs is usually greater than in case of other materials because of the difficult placement. GSCs and geobags are often employed as revetments or as seaward slopes of nearshore structures. Unfortunately, no exhaustive analyses regarding element stability are available the need to combine numerical and physical models with practice and experience in the field to establish the real stability of the GSC remains. </br>
For more detailed information, see [[Sand-filled geosystems in coastal engineering]].

[[Image:NarrowNeckASR.jpg|thumb|400px|left|Figure 1. Near-shore part of the Narrowneck articial surfing reef at the Gold Coast, Australia.]]

The Narrowneck reef (figure 1) is perhaps the most successful example of an '''Artificial Surfing Reef''' (ASR) because it requires a modest maintenance degree, while a lot of benefits are obtained in terms of coastal defense and development of surfing sports. The required maintenance after the construction has been very low, consisting in the addition of only 50 GSCs in 6 years (Jackson et al, 2007<ref name = "Jack">Jackson, L, Corbett, B., Tomlinson, R., McGrath, J., Stuart, G., 2007. Narrowneck Reef: Review of Seven Years of Monitoring. Shore and beach 75(4)</ref>). The main objectives of this ASR were to enlarge the beach and to improve the spot surfability. Therefore, this reef consists of two arms with a central channel in between to ensure slow [[rip current]]s (Jackson et al, 2002<ref name="Jack2"/>). The ASR in Narrowneck is composed of 458 geotubes, placed at depths ranging between 1.5 (crest) to 10 meters water depth (low tide). The reef is 270 m long (cross shore direction) and 170 m wide (longshore direction), covering a total volume of 120,000 m3. The geotextile sand containers were filled with 100-300m<sup>3</sup> of native sand in order to eliminate the contamination hazard in case of breaking (Jackson et al, 2002<ref name= "Jack2">Jackson, L.A., Tomlinson R., McGrath, J., Turner, I., 2002. Monitoring of a multi functional submerged geotextile reef breakwater. Proceedings of the 28th International Conference on Coastal Engineering 7-12th July 2002 Cardiff, Wales.</ref>). The Narrowneck reef contributes significantly to the stabilisation of the nourished beach and induced the formation of a salient which is approximately 50 m wide cross-shore. With regards to the second goal, surfable waves are reproduced on average for 184 days/year, with spilling or plunging breakers in case of weak storms and typically plunging breakers for intense storms (Jackson et al, 2007<ref name = "Jack"/>). Finally, the GSC surface was found to be intensely colonized by marine flora (Jackson et al, 2007<ref name = "Jack"/>).

===Reef units===
[[Image:ArtificialReefUnits.jpg|thumb|right|250px|Figure 2: Examples of different reef units]]
Reef units of different shapes and constructive characteristics can be used to produce ARs. Their macro-roughness reduces the incident wave agitation above the reef, creating local turbulence and vortices. Usually they are made by steel, reinforced or pre-stressed concrete, fibreglass or a variety of composite materials. These units are produced individually on shore and transported to the staging area. Here they could be combined in a variety of configurations thus allowing adjustment to local conditions and needs. Most of the units are designed to provide nursery areas for fish, to permit a good water recirculation, promote current deflections and marine colonization (O’Leary, 2001<ref name="OL">O’Leary, Hubbard T., O’Leary D. Artificial Reefs Feasibility Study, Coastal Resources Centre National University of Ireland Cork, 2001</ref>). Some examples are shown in figure 2. </br>

Figure 2e shows the so-called tecnoreef modules. Constructed from concrete-based natural products, they pose little impact on the ecosystem. Each module consists of reinforced octagonal plates, which are characterized by holes (usually four) having a quarter of a circle shape. The modules are assembled together to create a sort of pyramid that usually consists of three octagonal plates, the so called “base system”. The structure basis is made larger than the crest thus ensuring the resistance and stability to cross-shore currents and drag forces. They globally reduce cross-shore currents due to friction and turbulence. The consequent deposition of transported sediments within and around the pyramids is increased by the differently inclined facets on the external and internal surfaces of the modules. These irregularities facilitate localized microcurrents and create continuous circular currents (spheres of water) which release their energy upwards within each element. The constant circulation and exchange of water allows the influx of nutrients and permanent occupation by flora and fauna. <br/>

Equally note-worthy are the reef ball elements shown in figure 2f. These have an hemispherical shape (Harris, 1995<ref>Harris, L.E., 1995. Engineering design of artificial reefs. ''Oceans '95'', Marine Technology Society, Washington, D.C.,
Vol. 2, pp. 1139-1148.</ref>) and are typically 1-2 m high and 2 m wide. A reef ball is made by polyester with glass reinforcement and is thus very resistant to corrosion. The reef ball contains a buoy that allows it to float during construction phase and that is deflated when the element is definitively placed. They are characterised by high porosity (40-50%), roughness and many cavities or holes which have a double action. First off, the roughness and holes increase the structure complexity which assures a quick colonisations by marine species and aquatic plants (Pilarczyk, 2003<ref name="Pila">Pilarczyk, K.W., 2003. Alternative systems for coastal protection: an overview. International Conference on Estuaries and Coasts November 9-11, 2003, Hangzhou, China.</ref>). Secondly, these structures are specifically designed to generate turbulence, vortices and vertical jets which dissipate wave energy. Under storm attacks, the geometry of reef balls reduces the stability whereas the porosity, through the reduction of lifting forces, causes a beneficial compensating effect. </br>

The Grand Cayman reef (Cayman Islands) was one of the first examples of a Reef ball artificial reef. Between 2002 and 2005, approximately 230 Reef Ball units, ranging in size between 9 to 11 m width and 1.3 to 1.6 m height, were placed in 5 rows on the predominantly rocky bottom (Harris, 2009<ref name="Harris">Harris, L.E., 2009. Artificial Reefs for Ecosystem Restoration and Coastal Erosion. ''Protection with Aquaculture and Recreational Amenities, Reef Journal''. '''1(1)''', pages 235-246.</ref>). A gap is placed in front of the shallowest and widest part of the adjacent natural rock reef. The purpose of the reef was to restore the beach in front of the “Marriott beach resort” that disappeared in 2002 due to severe erosion during storm surges. The monitoring activities during the years 2002-2007 (Arnouil, 2008<ref name= "Arn">Arnouil D.S., 2008. Shoreline Response for a Reef Ball Submerged Breakwater System Offshore of Grand Cayman Island. Thesis of Master of Science in Ocean Engineering, submitted to Florida Institute of Technology, Florida (2008).
[http://www.reefball.org/album/caymanislands/Caymanmarriottbreakwaterproject/scientificreports/shorelineresponseforareefballsubmergedbreakwatersystemoffshoregrandcaymanislandbydanaarnouil.pdf]</ref>) documented an average shoreline accretion of 18 m just 3 months after the reef installation and an almost complete beach restoration (peak width of 30 m) in 2006. The profile of the beach showed some relevant changes. In 2002, before the construction of the reef, the elevation of the highest point was below mean sea level. After the reef construction there was a significant increase in elevation, from +1.0 m to +1.8 m along the shore (3 months later). Between 2003 and 2007 a berm formation was observed in correspondence of the reef. The berm height (from +0.7 m to +1.0 m) and width (from 7 m to 10 m) are increased significantly till the summer of 2007 and then appeared stable same till now (Arnouil, 2008<ref name="Arn"/>). </br>

==Geometry==
[[Image:ARLayout.jpg|thumb|right|250px|Figure 3: Potential planform layouts for artificial reefs]]
===Layout===
There are many schemes adopted for ARs, especially for those made by geotextile, depending on their principal function. After defining the objectives to be achieved, an appropriate geometry can be selected. Here, the case of submerged structures that are used to defend the coast from erosion are primarily considered. The layout in figure 3a represents the traditional configuration of gap separated rubble mound barriers parallel to the littoral zone. The waves that break over the reef induce an inshore increase of sea level and a simultaneous decrease of wave height due to energy dissipation over the crest (Pilarczyk, 2003<ref name = "Pila"/>). Figure 3b - 3f shows some sample layouts for artificial reefs and artificial surfing reefs (ASRs). Overall, the structure is composed by two convergent wedges and a focus where the waves break (Ranasinghe et al., 2006<ref>Ranasinghe, R., Turner, I.L., 2006. Shoreline response to submerged structures: A review. ''Coastal Engineering''. '''53''', 65– 79.</ref>), defining a-frame waves, i.e waves that break in a central point while the breakpoint evolves in a symmetrical way from the case of submerged structures that are used to defend the coast from erosion. The geometries in figures 3d and 3f show a large front of the structure parallel to the shore and thus are characterized by an intermediate behaviour between a simple AR and an ASR. Many modifications exist where a central channel (also referred to as a rip channel or paddling channel) is introduced to the scheme (Van Ettinger, 2005<ref name="VanEtt">Van Ettinger, H.D., 2005. Artificial surf reef design. Thesis at Delft University of Technology, 2005.</ref>). Fig. 3f represents such an ASR with a central gap. The focus gap can be at the same depth of the seabed or raised from it. The rip channel reduces the intensity of [[rip current]]s and thus increase safety of surfers.

===Cross-section===
[[Image:ARCross.jpg|thumb|right|250px|Figure 4: Some typical cross sections of artificial reefs]]
The cross-section of ARs varies according to the used materials and the main function of the structure. Figure 4a shows the cross section of a submerged barrier made of GSCs. The crest width of such a reef is much greater than that of traditional low crested structures and rubble mound breakwaters. The crest width must in fact be sufficiently large to dissipate wave energy (Pilarczyk, 2003<ref name="Pila"/>). Moreover, both seaward and landward slopes are steeper than in traditional breakwaters, reducing the volumes of material together with construction costs. In the body of the barrier, GSCs are longitudinally disposed whereas on the landward and seaward slopes GSCs are transversely disposed (Koerner et al., 2006<ref>Koerner, G.R., Koerner, R.M., 2006. Geotextile tube assessment using a hanging bag test. ''Geotextiles and Geomembranes''. '''24''', 129–137</ref>). This reduces the number of gaps which are exposed to breaking waves, increasing AR stability (Recio et al., 2009<ref name="Recio">Recio, J., Oumeraci, H., 2009. Process based stability formulae for coastal structures made of geotextile sand containers. ''Coastal Engineering''. '''56''', 632–658.</ref>).
In figure 4b, the body of the reef is composed by differently sized GSCs in order to fill all the gaps between the GSCs (Recio et al., 2009<ref name="Recio"/>), while the seaward and landward slopes are covered by geotubes. Clearly, for geotubes stability the angle at seabed must be lower than in the previous scheme. Figure 4c shows an Aquareef that is composed by an internal core made of rubble stones and one upper layer of special blocks that induce localized turbulence, dissipating incident wave energy. This scheme is the most common on Japanese coasts (Pilarczyk, 2003<ref name="Pila"/>). The Iburi reef in Hokkaido is an example of this peculiar reef design. In figure 4d the core of the reef is made of geotubes characterized by different dimensions while armour and filter layers are composed by stones (Pilarczyk, 2003<ref>Pilarczyk, K.W., 2003. Design of low-crested (submerged) structures – an overview. 6th International Conference on Coastal and Port Engineering in Developing Countries, Colombo, Sri Lanka.</ref>). This ASR profile is characterized by a submerged crest over which the waves peel (figure 4). A linear or convex profile for wedges can be adopted (Van Ettinger, 2005<ref name="VanEtt"/>). A convex profile can better compensate the change of the breaker intensity but it is more difficult to be constructed while the easier constructed linear profile creates the phenomenon of “wave pinching” i.e. a reduction of the pipe under plunging waves (Mead, 2003<ref>Mead, S., 2003. Surfing Science. Proceedings of the 3rd International Surfing Reef Symposium, Raglan, New Zealand, June 22-25, 2003.</ref>). At the back of the ASR, wedges can be cut or uncut to modulate the velocity of rip and longshore currents. If a cut profile for wedges is adopted, the velocity of rip currents is generally lower than with the un-cut profile (Van Ettinger, 2005 <ref name="VanEtt"/>). </br>

===Dimensions===
The size of the barrier depends on its use. If we consider a barrier for coastal protection, as in figure 3a, the parameters to be estimated are the crest and gap width (Pilarczyk, 2003<ref name="Pila"/>). For the first it is important to define the desired transmitted wave height or, in other words, the transmission coefficient. For the second, it is important to estimate the [[rip current]] velocities in order to establish an appropriate gap width. Moreover, it has to be considered that an increase of the rip channel may decrease the speed of rip currents but, at the same time, it may increase the transmission coefficient <math>K_T</math> (Van der Meer et al., 2005<ref name="VDM">Van der Meer, J. W., Briganti, R., Zanuttigh, B.,Wang, B., 2005. Wave transmission and reflection at low-crested structures: Design formulae, oblique wave attack and spectral change. ''Coastal Engineering''. '''52''', 915–929.</ref>). Another critical parameter is crest submergence, since it has to cope with the desired value of <math>K_T</math> as well as account for safe conditions for swimmers and surfers within the tidal excursion of the construction site.

The depth of the structure crest has to be related to the breaking wave height at the toe of the structure. For irregular depth-limited waves in the surf zone (saturated wave breaking) the height <math>H_b</math> of breaking waves is given by the empirical relation(USACE, 2012<ref name=CEM>USACE, 2012. Coastal engineering manual. Report No 110-2-1100. Washington DC: US Army Corps of Engineers https://www.publications.usace.army.mil/USACE-Publications/Engineer-Manuals/u43544q/636F617374616C20656E67696E656572696E67206D616E75616C/</ref>)

<math>H_b = \gamma_b h_b </math>,

where <math>h_b</math> is the still water depth at the toe of the structure and <math>\gamma_b</math> an empirical parameter in the range 0.4-1.2 that depends on the bed slope and the breaker type. The most usual value is <math>\gamma_b \approx 0.8</math>, see [[Shallow-water wave theory#Wave Breaking|wave breaking]].

The appropriate crest width of the reef (<math>B</math>) must be greater than the plunge distance which is the distance between plunge and break point, in order to assure that waves break over the crest. The plunge distance can be derived from the formula (Smith and Kraus, 1990<ref>Smith, E. R., Kraus, N.C., 1991. Laboratory study of wave-breaking over bars and artificial reefs. ''Journal of Waterway, Port, Coastal and Ocean'', 1991.</ref>)

<math>X_p=H_b \cdot (0.63\xi^{-1}+1.81)</math>.

The Iribarren and Battjes parameter <math>\xi=\large\frac{m}{\sqrt(H/L)} \normalsize </math> must satisfy the condition <math> \; 0.29 < \xi < 3.46 </math>. Here is <math>m=\tan \beta</math> the bed slope, and <math>H, L</math> are the wave height and wave length at deep water, respectively.

Wave transmission over the structure is given by the wave transmission coefficient <math>K_T</math>, the ratio of the transmitted and incident wave heights.
<math>K_T</math> is typically in the range 0.3-0.7 for a cross-section of an Aquareef (figure 4). Transmitted wave heights decrease with increasing relative wavelength and are affected by wave breaking. It is observed that wave energy dissipation (Hamaguchi et al., 1992<ref>Hamaguchi, N. Watanuki, A., Hasegawa, M., Noguchi, M., 1991. Development of submerged breakwaters for harmonized fisheries. ''Proceedings of The Japanese Society of Fisheries Engineering'', '''67-68'''.</ref>) is greater for the Aquareef unit type than for the rubble stones, though the values are similar when <math>R_c / H_i < 1</math>, where <math>R_c</math>= the still water depth above the structure crest (freeboard), <math>H_i</math>= the incident wave height. Therefore <math>K_T</math> can be determined by formulae valid for usual submerged rubble mound structures, see [[Stability of rubble mound breakwaters and shore revetments#Submerged structures| submerged structures]]. If <math>R_c / H_i < 1/3</math>, waves easily break on the wide aquareef and in this particular case <math>K_T</math> is smaller than for usual submerged rubble mound structures (Hirose et al., 2002<ref>Hirose, N., Watanuki, A., Saito, M., 2002. New Type Units for Artificial Reef Development of Eco-friendly Artificial Reefs and the Effectiveness Thereof. PIANC Congress, Sydney, see also 28th ICCE, Cardiff.</ref>).

Stability criteria for the armor stone elements are given in [[Stability of rubble mound breakwaters and shore revetments]]. For the stability of sand-filled geocontainers, see the appendix.

==Artificial Surfing Reefs (ASR)==

For artificial surfing reefs, the dimensions of the arms strongly depend on the extension of the surf area and on the desired breakpoint length. The design elements to define are the crest submergence, wedge slopes, rip-channel width and aperture angle <math>\delta</math>. Crest submergence can be designed based on the criteria already provided. The main goals of the ASR wedges are to create surfable breakers (Ranasinghe et al., 2006<ref>Ranasinghe R., Turner, I.L., 2006. Shoreline response to submerged structures: A review. ''Coastal Engineering''. '''53''', p65– 79</ref>), according to the required surf category (bodysurfing, bodyboard, paddle board, short board, etc.). Therefore the wedge slopes m must be determined basing on appropriate values of the Iribaren/Battjes parameter <math>\xi</math> (Battjes, 1974<ref>Battjes J. A., 1974. Surf Similarity. Proceedings 14th Coastal Engineering Conference, ASCE, pp: 466-480.</ref>). Surfable breakers are characterized by <math>0 < \xi <0.5 </math> for spilling and <math>0.5 < \xi < 3.3</math> for plunging breakers, but is also preferable to have values between 2.0 and 3, which clearly characterize plunging breakers (Scarfe, 2002<ref>Scarfe, B. E., 2002. Categorising Surfing Manoeuvres Using Wave and Reef Characteristics. Unpublished MSc Thesis, University of Waikato, Hamilton, New Zealand.</ref>). Moreover, in the plunging category, it is possible to distinguish the type of breaker based on the vortex ratio defined as follows (Mead and Black, 2000<ref name="mb">Mead, S. T., Black, K. P., 2000. Predicting the Breaking Intensity of Surfing Waves. ''Special Issue of the Journal of Coastal Research on Surfing'', pp: 51-65.</ref>): <math>VR=\large\frac{F}{W} \normalsize </math> with <math>F</math> and <math>W</math> being the tube dimensions subtended by the plunging breaker. <math>VR</math> also depends on seabed slope <math>m</math> and particularly it increases as <math>m</math> decreases. Plunging breakers are characterized by low values of <math>VR</math> (typically between 1.6-2.5), while higher values of <math>VR</math> characterize less intense breaking. Generally, vortex ratio depends on slope <math>m</math> as follows (Mead and Black, 2000<ref name="mb"/>) <math>VR=0.065 \cdot m^{-1}+0.821</math>.

Finally, the rip channel elements must be fixed in order to reduce the speed of central and lateral [[rip current]]s. Unfortunately, no formulae have been developed so far that synthetically provide <math>b</math> and <math>\delta</math>; but some examples of numerical models exist in literature (Van Ettinger, 2005<ref name="VanEtt"/>; Muilwijk, 2005 <ref>Muilwijk, M.P., 2005. Artificial Surf Reef on Maasvlakte 2, Msc.Thesis, Delft University of Technology, Faculty of Civil Engineering and Geosciences, Section of Hydraulic Engineering, june 2005.</ref>; Trung, 2006<ref>Trung L.H., 2006. Interacting Artificial Surf Reefs, MSc Thesis, 2006 (downloadable from www.jcronline.org).</ref>) which show that by increasing of angle <math>\delta</math>, the rip current through the channel decreases (Van Ettinger, 2005<ref name="VanEtt"/>). </br>

==Function==
Artificial reefs (ARs) dissipate incident waves by breaking and thereby reduce inshore wave agitation and increase the tendency to create geomorphologic forms (Pilarczyk, 2003<ref name="Pila"/>), i.e salient or tombolo, which vary accordingly to AR dimensions and to sediment size. The rules for low-crested structures (LCSs) and ARs are given below (Pilarczyk, 1996<ref>Pilarczyk, K.W. and Zeidler, R.B., 1996. Offshore breakwaters and shore evolution control, A.A. Balkema, Rotterdam.</ref>):

<math>\large\frac{L_S}{X} \normalsize > 0.66 (1-K_T)</math> (tombolo),
<math>\quad \large\frac{L_S}{X} \normalsize > \large\frac{1}{(1-K_T)}</math> (salient and single reef),
<math>\quad \large\frac{G L_S^2}{X} \normalsize >0.5 (1-K_T)</math> (salient and multi-reef),

where <math>L_S</math> is the longshore dimension of the reef and <math>X</math> the offshore distance.
The gap width is usually <math>L \le G \le 0.8 L_S</math>, where <math>L</math> is the wave length. Field data along Australian coasts indicate that tombolo and salient formation (Black and Andrews, 2001<ref name="BaA">Black, K. and Andrews, C.J., 2001. Sandy Shoreline Response to Offshore Obstacles, Part I: Salient and tombolo geometry and shape, Part II: Discussion of Formative Mechanisms. ''Journal of Coastal Research, Special Issue on Surfing''.</ref>) occurs when:

<math>\large\frac{L_S}{X} \normalsize > 0.6</math> (tombolo), <math>\quad \large\frac{L_S}{X} \normalsize < 2</math> (salient).

Furthermore, the distance between the tip of the salient and the offshore reef (<math>X_{off}</math>) can be predicted from the longshore dimension of the offshore reef (<math>L_S</math>) by the following formula (Andrew, 1997<ref>Andrews, C.J., 1997, Sandy shoreline response to submerged and emerged breakwaters, reefs or islands. Unpublished Thesis, University of Waikato, New Zealand</ref>): <math>\large\frac{X_{off}}{L_S} \normalsize =0.5 \left(\large\frac{L_S}{X} \normalsize \right)^{-1.27}</math>.

Ming and Chiew (2000<ref>Ming D., and Chiew, Y-M., 2000. Shoreline Changes behind Detached Breakwater. ''J.Waterway, Port, Coastal, and Ocean Engng.'' '''126(2)''', March/April.</ref>) showed that salient occurs behind a detached breakwater when <math>\large\frac{X}{L_S} \normalsize >0.8</math> and determined the plan area of sand deposition (<math>A</math>) as the area enclosed by the initial shoreline and the shoreward equilibrium shoreline: <math>\large\frac{A}{X^2} \normalsize =-0348+0.043\large\frac{X}{L_S} \normalsize +0.711\large\frac{L_S}{X} \normalsize </math>.

Problems resulting from larger submergence <math>R_c</math> are different for ARs or for ASRs as they are mainly related to their specific purposes (Pilarczyk, 2003.a<ref name="Pila"/>). For an AR, <math>R_c</math> directly affects the transmission coefficient <math>K_T</math> and hence a higher residual wave agitation behind the reef will be observed. Therefore, the AR tends to be less effective for coastal defence and the most common way to restore the initial value of <math>R_c</math> is to perform a rock/element recharge on the structure crest. For an ASR, the problem is the increase of <math>K_T</math> and a decrease of spot surfability, due to an increase of breaking wave heights based on depth limited conditions (Van Ettinger, 2005<ref name="VanEtt"/>). This means that a greater surfer ability is required to ride the waves (Mead, 2003), and this may decrease the number of persons for which the ASR was originally conceived. Additionally, the number of surfable days per year may decrease (Mead, 2000a), since higher incident waves are needed to maintain the same hydrodynamic conditions over the reef. Also in this case, the most common way to cope with sea level rise and changes of <math>R_c</math> is to place one or more additional layers of material over the ASR crest.

==Related articles==
:[[Detached breakwaters]]
:[[Stability of rubble mound breakwaters and shore revetments]]
:[[Sand-filled geosystems in coastal engineering]]
:[[Ecological enhancement of coastal protection structures]]

==External sources==
:The ''Rock Manual'' (2007)<ref name=Rock> CIRIA/CUR/CETMEF 2007. The Rock Manual. The use of rock in hydraulic engineering (2nd ed.). C683. London: CIRIA </ref>
:The ''Coastal Engineering Manual'' (2012)<ref name=CEM></ref>
:The ''Eurotop Manual'' (2018)<ref name=EU>Van der Meer, J.W., Allsop, N.W.H., Bruce, T., De Rouck, J., Kortenhaus, A., Pullen, T., Schüttrumpf, H., Troch, P. and Zanuttigh, B. 2018. Manual on wave overtopping of sea defences and related structures, 2nd ed. http://www.overtopping-manual.com/</ref>

==Appendix: Design of Artificial Reefs made of Geotextile Sand Containers (GSCs) ==

[[Image:GSC forces.jpg|thumb|right|250px|Figure 5: Forces acting on a GSC unit]]
Specific analysis of structure stability '''under non breaking waves''' exists in the literature for ARs made by GSCs or geobags (Recio et al, 2009<ref name="Recio"/>) or reef units (Harris, 2009<ref name="Harris"/>). In case of structures made by stones, design methods refer essentially to the studies available for LCSs (Burcharth et al., 2007<ref>Burcharth, H. F., Hawkins, S., Zanuttigh, B. and Lamberti, A., 2007. ''Environmental Design Guidelines for Low Crested Coastal Defence Structures'' Elsevier.</ref>). Few studies exist dealing with deeply submerged structures that may act as a local increase of bottom roughness that dissipates energy depending on local wave length (Corvaro et al., in press<ref>Corvaro, S., Mancinelli, A., Brocchini, M., Seta, E., Lorenzoni, C., On the wave damping due to a permeable seabed. ''Coastal Engineering'', In Press.</ref>). The force system acting on a single GSC is summarised in figure 5. In this scheme, the container is assumed to be a rigid body and is characterised by a width that is half of the length <math>l_c</math> and a height is 0.2 times the length.

The forces acting on GSC are (Recio et al, 2009<ref name="Recio"/>

Drag force <math>F_D=0.5 C_d \cdot \rho_w \cdot A_s \cdot u^2 ; \quad</math>
Inertia force <math>F_i=C_m \cdot \rho_w \cdot V \cdot \partial u / \partial t ; \quad</math>
Lift force <math>F_L=0.5 \cdot C_L \cdot \rho_w \cdot A_T \cdot u^2 ; \quad</math>

Buoyancy force <math>F_B=g \cdot \rho_w \cdot V ; \quad </math>
Weight force <math>F_{GSC}=g \cdot \rho_s \cdot V \quad</math>,

where <math>A_t=l_c^2/2, \quad A_s=l_c^2/10, \quad V=l_c^3/10</math>, and where <math>C_d, C_m, C_L</math> are drag, inertia and lift coefficients, respectively. These can be estimated based on experimental results (Recio, 2008<ref name="Recio08">Recio J. 2008, Hydraulic Stability of Geotextile Sand Containers for Coastal Structures –Effect of Deformations and Stability Formulae – PhD Thesis, Leichtweiss Institute for Hydraulic Engineering and Water Resources.</ref>). The sliding and overturning equilibrium conditions are, respectively (Recio et al, 2009<ref name="Recio"/>),

<math>\mu (F_{GSC}-F_L) \ge F_D + F_M , \quad F_{GSC} l_c/2 \ge F_M l_c /10 + F_D l_c /10 + F_L l_c /2 , </math>

where <math>\mu</math> is the dimensionless friction factor and <math>u</math> the orbital velocity. A key issue for the proper design of ARs made with GSC is to account for the effect of the GSC deformation. GSC deformability can be taken into account (Recio et al, 2009 <ref name="Recio"/>) by 1) introducing new deformation factors for the mobilizing forces (<math>K_{CD}, K_{CL}, K_{CM}</math>) dependent of the sand fill ratio of GSC, wave conditions, properties of the filling material and deformation of the geotextile; 2) by introducing new deformation factors for the resisting forces (<math>K_R</math>) which depend on sand fill ratio of GSC, properties of the filling material, wave conditions, steepness of the structure slopes and position and number of adjacent GSCs; 3) by modifying the existing force coefficients (<math>CD, CM, CL</math>). However, <math>CD</math> and <math>CL</math> are a function of the Reynolds number <math>Re</math> and of the roughness and thus they are influenced also by the wave-induced flow around the GSC and by its shape.

Physical model tests (Recio, 2008) <ref name="Recio08"/> are the only way to derive the corresponding coefficients modified by deformations effects (<math>CD', CM', CL'</math>). Approximation for the values of these coefficients can be found in Recio and Oumeraci (2009) <ref name="Recio"></ref>. Expressions to estimate the new coefficients to be introduced are first synthesised in case sliding equilibrium is considered. Regarding the resisting force <math>F_{GSC}</math>, the GSC deformations affects the projected weight forces of the GSC and thus also modifies its stability (Recio et al., 2009). Generally, <math>K_R</math> varies accordingly to the part of the structure that is considered, particularly the slope or the crest. In order to estimate sliding deformation factors (<math>KS_{CD}, KS_{CL}, KS_{CM}</math>) the condition for sliding equilibrium, Eq. (30), is applied. <math>KS_{CD}</math> can be evaluated only by the variation of the projected area <math>A'_S=0.14 \, l_c^2</math> normal to the wave direction (Recio et al., 2009<ref name="Recio"/>) as follows: <math>KS_{CD}=A'_S / A_S=1.4</math>.

Since the volume of the container remains constant (thus the influence of shape variation on the added mass is small) and inertia forces are smaller than drag forces, especially in shallow water, <math>KS_{CM}</math> can be assumed equal to 1,0 (Recio et al., 2009<ref name="Recio"/>). <math>KS_{CL}</math> is influenced by the variation of the projected area in the wave direction (<math>A'_T = 0.47 \, l_c^2</math>) and thus results: <math>KS_{CL}=A'_T / A_T =0.94</math>.
Finally, the deformation factor for the resisting force is defined as <math>KS_R=V'/ V</math>, where <math>V'=0.16 \, l_c^3</math> and <math>V = 0.1 \, l_c^3</math>, giving <math>KS_{R}=\large\frac{V\prime}{V}\normalsize =1.60</math>.
However, <math>KS_R</math> depends also on the seabed slope angle <math>\beta</math> (Recio et al., 2009 <ref name="Recio"/>):
<math>KS_R=0.0007 \cdot \beta^2 +0.25 \cdot \beta-6.83</math>.
Since similar deformations occur for containers placed on the slope and on the crest, it is reasonable to assume that the deformation factors are the same with the exception of <math>KS_R</math>. In fact shape variations are greater for GSCs placed on the seaward slope than on the crest (Recio, 2008<ref name="Recio08"/>). For GSC on the crest, <math>KS_R</math> becomes
(Recio et al., 2009 <ref name = "Recio"/>): <math>KS_{R}=\large\frac{V\prime}{V}\normalsize =0.70</math> and depends on the slope angle: <math>KS_R=-0.00009 \cdot \beta^2 +0.019 \cdot \beta-0.008</math>.

Expressions to estimate the new coefficients to be introduced are now synthesised in case overturning equilibrium is considered. For the overturning equilibrium the deformation factors <math>KO_{CD}, KO_{CM}, KO_{CL}, KO_{R}</math> account, in this case, for the variation both of forces and moments (Recio et al., 2009<ref name="Recio"/>). For the moment due to the drag force, the factor <math>KO_{CD}</math> should be estimated as: <math>KO_{CD}=\large\frac{A\prime_S}{A_S}\normalsize \cdot \large\frac{z\prime_{CD}}{z_{CD}}\normalsize \cong1.54</math>.
Similarly, deformation factors related to Morison (inertia) and lift forces are respectively:
<math>KO_{CM}=\large\frac{z\prime_{CM}}{z_{CM}}\normalsize \cong1.1, \quad KO_{CL}=\large\frac{A\prime_t}{A_t}\normalsize \cdot \large\frac{x\prime_{CL}}{x_{CL}}\normalsize \cong0.80</math>, where <math>z</math> is moment arm on the <math>z</math>-axis.
Finally, assuming that the GSC volume in deformed configuration is the same as in the non-deformed configuration, <math>KO_R</math> results: <math>KO_{R}=\large\frac{x\prime_{GSC}}{x_{GSC}}\normalsize \cong0.92</math>, with <math>x</math> being the moment arm on the <math>x</math>-axis.

To apply the hydraulic stability formulae, the required parameters are:
*the wave-induced horizontal velocity <math>u</math> at the depth of the critical GSC. This velocity can be derived from simple analytical models based on linear wave theories.
* the wave-induced horizontal acceleration at same depth <math>\partial u / \partial t</math>;
* the friction factor <math>\mu</math> between GSCs, which can be derived from physical model tests;
* the force and deformation coefficients.

However, in the design phase it is too difficult to define <math>C_D, C_M, C_L</math> because they are functions of the Reynolds number, that also depends on the unknown size of the container. The following iterative procedure is proposed (Recio et al., 2009<ref name="Recio"/>):
# by using linear wave theory, the wave-induced orbital velocity <math>u</math> and acceleration <math>\partial u / \partial t</math> at the depth of the critical container can be calculated;
# the Reynvolds number <math>Re</math> is computed and consequently the coefficients <math>C'_D, C'_M, C'_L</math> and the deformation factors <math>K_{CD}, K_{CM}, K_{CL}, K_{R}</math> can be selected from the corresponding range (Recio, 2009<ref name="Recio"/>);
# the GSC length <math>l_{GSC}</math> is derived as the length that satisfies the equilibrium conditions for sliding and overturning;
# based on the obtained value for <math>l_{GSC}</math>l<sub> value, calculate again Reynolds number <math>Re</math>, <math>C'_D, C'_M, C'_L, K_{CD}, K_{CM}, K_{CL}, K_{R}</math>, and then re-calculate the required length <math>l_c</math>.
It is recommended to use the maximum velocity <math>u</math> together with the maximum acceleration <math>\partial u / \partial t</math> (Recio et al., 2009<ref name="Recio"/>), although their phases are shifted by <math>\pi / 2</math> and theoretically, when occurs the maximal drag force (influenced by <math>u^2</math>), the inertia force <math>F_M</math> (influenced by <math>\partial u / \partial t</math>) tends to zero. </br>

'''Under breaking waves''', the GSC behaves as flexible body, being uplifted and deformed by wave impact. Breaking wave loads cause very high overpressures on GSC surfaces in very short time intervals and therefore the elements are exposed to static and impulsive loads. In these conditions, it may happen that high pressures, especially at sea water level, tend to separate adjacent GSCs, generating a flow in between and a resulting increase of the pressures acting on the seaward slope of around two times, due to the superposition of incoming and reflected waves from the gaps. This process could lead to a seaward displacement of GSCs and thus be critical for structure stability. </br>

Currently, not many studies have investigated the stability of reef units '''under regular wave attacks'''. This is due to their different shapes and geometries that make it difficult to elaborate a generalized theory. In this section only the reef balls are considered. Other reef elements are characterized by different geometries and shapes, which generally cannot be compared to that of Reef Balls and hence require specific knowledge beyond the following. The stability criterion is derived by applying the sliding equilibrium (Harris et al., 1998<ref name="Har"/>), where the horizontal wave force acting on the reef unit can be decomposed into drag and inertia forces and the resisting force is due only to the friction between the element and the seabed (Harris et al., 1998<ref name="Har"/>). Therefore. in order to estimate the right dry weight that ensures the stability, the sliding equilibrium can be rewritten as (Harris et al., 1998<ref name="Har">Harris L.E., Gonzalez J.E.C., 1998. Stability analysis for the submerged Reef Ball breakwater. proposed for the Mayan Palace Resort, Quintana Roo, Mexico", (1998
[http://www.artificialreefs.org/ScientificReports/CancunHotelRBstability.htm]</ref>):
<math>F_{W}\ge\large\frac{F_S}{\mu}\normalsize (F_D+F_i)+F_l+F_B ,</math>
where <math>F_D, F_i, F_B, F_L</math> can be estimated through the given equations above and <math>F_W</math> is the dry weight of the unit. The friction factor <math>\mu</math> can be assumed equal to 0.4 for sliding on sand bottom or 0.5 on hard bottom (Harris et al., 1998<ref name="Har"/>) and <math>F_S</math> is a safety factor. The forces are very difficult to estimate and thus several laboratory tests were carried out under regular waves in a wave tank (Harris et al., 1998<ref name="Har"/>). These tests provided for selected wave conditions a relationship between the unit weight and the water depth, which strongly affects the horizontal water particle velocity and acceleration and hence the drag and inertia forces. The initial relationship between depth and dry weight being almost linear, there is a peak that represents a critical depth value beyond which the minimum dry weight (and therefore, the stability) is not affected by the depth (i.e. the curves tend to become horizontal)(Harris et al., 1998<ref name="Har"/>).</br>
{{THESEUS}}

==References==
<div style="text-align": left;"><references/></div></br>

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Impact of tourism in coastal areas: Need of sustainable tourism strategy

2025-09-12T20:29:04Z

Admin: fix URL GSTC

This article discusses the current status of coastal [[tourism]], the associated issues and impacts. The article further provides recommendations for future management of coastal tourism.

==Introduction==
Since the 1992 Earth Summit in Rio de Janeiro, there is increasing awareness of the importance of sustainable forms of tourism. Although [[tourism]], one of the world largest industries, was not the subject of a chapter in [[Agenda 21]], the Programme for the further implementation of Agenda 21, adopted by the General Assembly at its nineteenth special session in 1997, included sustainable tourism as one of its sectoral themes. Furthermore in 1996, The World Tourism Organization jointly with the tourism private sector issued an Agenda 21 for the Travel and Tourism Industry, with 19 specific areas of action recommended to governments and private operators towards sustainability in tourism.

On the other hand, an analysis of the sustainability policies, strategies and instruments of 21 European countries revealed a gap between good theoretical approaches and the general willingness to support a sustainable tourism development and the realisation of it, and concluded that in hardly any of the countries is sustainable tourism put in the centre of the national tourism policy as a priority area<ref>Dickhut, H. and Tenger, A. (eds.) 2022. Review and Analysis of Policies, Strategies and Instruments for Boosting Sustainable Tourism in Europe. European SME Going Green 2030 Report, p. 505</ref>.

==Specific situation of coastal areas==

[[Coastal area]]s are transitional areas between the land and sea characterized by a very high biodiversity. They include some of the richest and most fragile ecosystems on earth, like [[mangroves]] and [[coral reefs]]. At the same time, coasts are under very high population pressure due to rapid [[urbanization]] processes. More than half of today’s world population live in coastal areas (within 60 km from the sea) and this number is on the rise.

Additionally, among all different parts of the planet, coastal areas are those which are most visited by tourists and in many coastal areas [[tourism]] presents the most important economic activity. In the [[Mediterranean Sea and Region, including Adriatic Sea|Mediterranean region]] for example, tourism is the first economic activity for islands like Cyprus, Malta, the Balearic Islands and Sicily.

Forecast studies carried out by WTO in 2000 estimated that international tourist arrivals to the Mediterranean coast would amount to 270 millions in 2010 and to 346 millions in 2020. However, the latter figure was reached already in 2015 <ref>[https://www.e-unwto.org/doi/pdf/10.18111/9789284416929 UNWTO]</ref>.

===Causes of coastal degradation===
Tourisms often contributes to coastal degradation. There are many other causes:
* Coastal zone urbanization
* Fisheries and [[aquaculture]]
* Port development and shipping
* Land reclamation
* Land-use conversion (Agriculture, Industrial development)
* [[Climate change]] and sea level rise
See also [[Threats to the coastal zone]].

{| border="0" align="center"
|-
| valign="top"|
[[File:tourism_fig1.jpg|thumb|450px|left|Recreational snorkelers harassing a whaleshark (Rhincodon typhus), © WWF-Canon/Erkki SIIRLIA]]
| valign="top"|
[[File:tourism_fig2.jpg|thumb|450px|left|Tourists sunbathing on a beach used by loggerhead turtles (Caretta caretta) for nesting, some with beach umbrellas which can hurt turtle nests. Zákinthos, Greece. © WWF-Canon / Michel GUNTHER]]
|}

==How does tourism damage coastal environment==

Massive influxes of tourists, often to a relatively small area, have a huge impact. They add to the pollution, waste, and water needs of the local population, putting local infrastructure and [[habitats]] under enormous pressure. For example, 85% of the 1.8 million people who visit Australia's Great Barrier Reef are concentrated in two small areas, Cairns and the Whitsunday Islands, which together have a human population of about 130,000.

===Tourist infrastructure===
In many areas, massive new tourist infrastructure has been built - including airports, marinas, resorts, and golf courses. Overdevelopment for tourism has the same problems as other coastal developments, but often has a greater impact as the tourist developments are located at or near fragile marine [[ecosystems]]. A few examples:
*[[mangrove]] forests and [[seagrass meadows]] have been removed to create open beaches;
*tourist developments such as piers and other structures have been built directly on top of [[coral reefs]];
*nesting sites for endangered marine turtles have been destroyed and disturbed by large numbers of tourists on the beaches.

===Careless resorts, operators, and tourists===
The damage is not only due to the construction of tourist infrastructure. Some tourist resorts empty their sewage and other wastes directly into water surrounding coral reefs and other sensitive marine [[habitats]].
Recreational activities also have a strong impact. For example, careless boating, diving, snorkeling, and fishing have substantially damaged [[coral reefs]] in many parts of the world, through people touching reefs, stirring up [[sediment]], and dropping anchors.
Marine animals such as whale sharks, seals, dugongs, dolphins, whales, and birds are also disturbed by increased numbers of boats, and by people approaching too closely.
Tourism can also add to the consumption of seafood in an area, putting pressure on local fish populations and sometimes contributing to overfishing. Collection of corals, shells, and other marine souvenirs - either by individual tourists, or local people who then sell the souvenirs to tourists - also has a detrimental effect on the local environment.

==The case of cruise ship tourism==
[[File:SymphonyOfTheSeas.jpg|thumb|350px|right|The mega-cruise ship Royal Caribbean’s Symphony of the Seas (228.000 GRT) is approximately five times the size of the Titanic (46.000 GRT). Photo credit Darthvadrouw, Creative Commons Licence.]]
Cruise ship tourism is a fast growing sector of the tourism industry during the past decades. While world international tourist arrivals in the period 1990 – 1999 grew at an accumulative annual rate of 4.2%, that of cruises did by 7.7%. In 1990 there were 4.5 million international cruise arrivals
which had increased to a number of 8.7 million in 1999 and to 27 million in 2019, with gross economic benefits estimated at $150 billion in direct, indirect and induced economic benefits<ref>https://www.f-cca.com/downloads/2018-Cruise-Industry-Overview-and-Statistics.pdf 2018 Cruise Industry Overview]</ref><ref>Papathanassis, A. 2022. Cruise tourism. In D. Buhalis (ed), Encyclopedia of Tourism Management and Marketing. Cheltenham: Edward Elgar Publishing, pp.
687–690</ref>. From the 1980s to 2018, the global cruise fleet grew from 79 to 369 vessels operating worldwide, and the average cruise ship size and capacity grew from 19.000 to 60.000 gross registered tonnage (GRT). Carrying on average 4,000 passengers and 1,670 crew, these enormous floating towns are a major source of marine pollution through the dumping of garbage and untreated sewage at sea, and the release of other shipping-related pollutants.

===Issues===
Problems caused by cruise tourism are ubiquitous and well-documented, especially for small island nations and the Mediterranean<ref>Moscovici, D. (2017) Environmental Impacts of Cruise Ships on Island Nations, Peace Review, 29: 366-373</ref><ref>Caric, H. and Mackelworth, P, (2014) Cruise tourism environmental impacts – The perspective from the Adriatic Sea. Ocean & Coastal Management. 102: 350-363</ref>.
* Discharge of sewage in marinas and nearshore [[coastal area]]s. The lack of adequate port reception facilities for solid waste, especially in many small islands, as well as the frequent lack of garbage storing facilities on board can result in solid wastes being disposed of at sea, and being transported by wind and [[tidal current|currents]] to shore often in locations distant from the original source of the material.
* Coral reefs. Land-based activities such as port development and the [[dredging]] that inevitably accompanies it in order to receive cruise ships with sometimes more than 3000 passengers can significantly degrade [[coral reefs]] through the build-up of [[sediment]]. Furthermore, sand mining at the beaches leads to [[coastal erosion]]. In the Cayman Islands damage has been done by cruise ships dropping anchor on the reefs. Scientists have acknowledged that more than 300 acres of [[coral reef]] have already been lost to cruise ship anchors in the harbour at George Town, the capital of Grand Cayman.
* Socio-cultural impacts. Cruise-ship tourism can produce socio-cultural stress, since it means that during very short periods there is high influx of people, sometimes more than the local inhabitants of small islands, possibly overrunning local communities. Vital resources such as food, energy, land, water, etc. may become depleted.
* Ship emissions. Fuel-based cruise ships currently produce large amounts of greenhouse gases. The gradual replacement is only now starting. From the approximately 100 new builds planned up to 2027, one-fifth are LNG powered, corresponding to 39% of the new tonnage and 41% of the added capacity<ref name=P23>Papathanassis, A. 2023. A decade of ‘blue tourism’ sustainability research: Exploring the impact of cruise tourism on coastal areas. Cambridge Prisms: Coastal Futures 1: 1–11</ref>.

Cruise tourism is often ascribed as hedonistic. However, a positive effect of expedition cruise tourism is its educational and awareness-creation potential for sustainability values and issues. It can transform a ‘sense of place’ to a ‘care of place’, encouraging tourists and locals to assume more responsibility<ref>Walker, K. and Moscardo, G. 2016. Moving beyond sense of place to care of place: The role of indigenous values and interpretation in promoting transformative change in tourists’ place images and personal values. Journal of Sustainable Tourism 24: 1243–1261</ref>.

==Impacts of coastal tourism==

[[File:AlexandriaAbuQirBeach.JPG|thumb|400px|right|Abu Qir beach, Alexandria.]]

===Environmental impacts===
* The intensive use of land by [[leisure and recreation|tourism and leisure]] facilities
* Overuse of water resources, especially groundwater, leading to soil subsidence and saline intrusion
* Changes in the landscape due to the construction of infrastructure, buildings and facilities
* Vulnerability to natural hazards and [[sea level rise]]
* Pollution of marine and freshwater resources
* Energy demand and consumption
* Air pollution and waste
* Disturbance of fauna and local people (for example, by noise)
* Loss of marine resources due to destruction of [[coral reefs]], overfishing
* Compaction and sealing of soils, soil degradation due to overuse of fertilizers and loss of land resources (e.g. [[desertification]], [[erosion]])
* Loss of public access

===Impacts on biodiversity===
Tourism can cause loss of [[biodiversity]] in many ways, e.g. by competing with wildlife for [[habitat]] and natural resources or by providing pathways for the introduction of alien species. Negative impacts on biodiversity are caused by various other factors, such as those mentioned above.

===Socio-cultural impacts===
Change of local identity and values:

*''Commercialization of local culture:'' [[Tourism]] can turn local culture into commodities when religious traditions, local customs and festivals are reduced to conform to tourist expectations and resulting in what has been called "reconstructed ethnicity".

*''Standardization:'' Destinations risk standardization in the process of tourists desires and satisfaction: while landscape, accommodation, food and drinks, etc., must meet the tourists expectation for the new and unfamiliar situation. They must at the same time not be too new or strange because few tourists are actually looking for completely new things. This factor damages the variation and beauty of diverse cultures.

*''Adaptation to tourist demands:'' Tourists want to collect souvenirs, arts, crafts, cultural manifestations. In many tourist destinations, craftsmen have responded to the growing demand and have made changes in the design of their products to make them more attractive to the new customers. Cultural erosion may occur in the process of commercializing cultural traditions.

Cultural clashes may arise through:
*Economic inequality - between locals and tourists who are spending more than they usually do at home.
*Irritation due to tourist behaviour - Tourists often, out of ignorance or carelessness, fail to respect local customs and moral values.
*Job level friction - due to a lack of professional training, many low-paid tourism-jobs go to local people while higher-paying and more prestigious managerial jobs go to foreigners or "urbanized" nationals.

==Benefits of Sustainable coastal tourism==
===Economic benefits===

[[Image:TouristArrivals.jpg|thumb|450px|right| International tourist arrivals (million) and tourism receipts (USD billion) <ref>International Tourism Highlights (2019) https://www.e-unwto.org/doi/pdf/10.18111/9789284421152 </ref>.]]

The main positive economic impacts of [[sustainable]] (coastal) [[tourism]] are: contributions to government revenues, foreign exchange earnings, generation of employment and business opportunities. Employing over 3.2 million people, coastal tourism generates a total of € 183 billion in gross value added and represents over one third of the maritime economy of the European Union. As much as 51% of bed capacity in hotels across Europe is concentrated in regions with a sea border<ref>Ecorys (2016) Study on specific challenges for a sustainable development of coastal and maritime tourism in Europe EC Maritime Affairs</ref>.

'''''Contribution to government revenues'''''<br/>
Government revenues from the tourism sector can be categorised as direct and indirect contributions. Direct contributions are generated by income taxes from tourism and employment due to tourism, tourism businesses and by direct charges on tourists such as ecotax. Indirect contributions derive from taxes and duties on goods and services supplied to tourists, for example, taxes on tickets (or entry passes to any protected areas), souvenirs, alcohol, restaurants, hotels, service of tour operators.

'''''Foreign exchange earnings'''''<br/>
Tourism expenditures, the export and import of related goods and services generate income to the host economy. Tourism is a main source of foreign exchange earnings for at least 38 % of all countries.

'''''Employment generation'''''<br/>
The rapid expansion of international tourism has led to significant employment creation. Tourism can generate jobs directly through hotels, restaurants, taxis, souvenir sales and indirectly through the supply of goods and services needed by tourism-related businesses (e.g. conducted tour operators). Tourism represents around 7 % of the world’s employees. Tourism can influence the local government to improve the infrastructure by creating better water and sewage systems, roads, electricity, telephone and public transport networks. All this can improve the standard of living for residents as well as facilitate tourism.

'''''Contribution to local economies'''''<br/>
Tourism can be a significant or even an essential part of the local economy. As environment is a basic component of the tourism industry’s assets, tourism revenues are often used to measure the [[Economic Value|economic value]] of protected areas. Part of the tourism income comes from informal employment, such as street vendors and informal guides. The positive side of informal or unreported employment is that the money is returned to the local economy and has a great multiplier effect as it is spent over and over again. The [https://www.gstc.org/ Global Sustainable Tourism Council (GSTC)] estimates that tourism generates an indirect contribution equal to 100 % of direct tourism expenditures.

'''''Direct financial contributions to nature protection'''''<br/>
Tourism can contribute directly to the conservation of sensitive areas and [[habitats]]. Revenue from park-entrance fees and similar sources can be allocated specifically to pay for the protection and management of environmentally sensitive areas. Some governments collect money in more far-reaching and indirect ways that are not linked to specific parks or conservation areas. User fees, income taxes, taxes on sales or rental of recreation equipment and license fees for activities such as hunting and fishing can provide governments with the funds needed to manage natural resources.

'''''Competitive advantage'''''<br/>
More and more tour operators take an active approach towards sustainability. Not only because consumers expect them to do so but also because they are aware that intact destinations are essential for the long term survival of the tourism industry. More and more tour operators prefer to work with suppliers who act in a sustainable manner, e.g. saving water and energy, respecting the local culture and supporting the well-being of local communities. In 2000 the international Tour Operators initiative for [[Sustainable]] Tourism was founded with the support of UNEP. In 2014 it merged with the [https://www.gstc.org/ Global Sustainable Tourism Council (GSTC)].

===Environmental Management and Planning benefits===
Sound and efficient environmental management of tourism facilities and especially hotels (e.g.water and energy saving measures, waste minimization, use of environmentally friendly material) can decrease the environmental impact of tourism. Planning helps to make choices between the conflicting interests of industry and tourism, in order to find ways to make them compatible. Planning sustainable tourism development strategy at an early stage prevents damages and expensive mistakes, thereby avoiding the gradual deterioration of the quality of environmental goods and services significant to tourism.

===Socio-cultural benefits===
'''''Tourism as a force for peace'''''<br/>
Travelling brings people into contact with each other. As [[sustainable]] [[tourism]] has an educational element it can foster understanding between people and cultures and provide cultural exchange between guests and hosts. This increases the chances for people to develop mutual sympathy, tolerance and understanding and to reduce prejudices and promote the sense of global brotherhood.

'''''Strengthening communities'''''<br/>
[[Sustainable]] Coastal [[Tourism]] can add to the vitality of communities in many ways. For example through events and festivals of the local communities where they have been the primary participants and spectators. Often these are refreshed, reincarnated and developed in response to tourists’ interests.<br/>
The jobs created by tourism can act as a very important motivation to reduce emigration from rural areas. Local people can also increase their influence on tourism development, as well as improve their jobs and earnings prospects through tourism-related professional training and development of business and organizational skills.

'''''Revitalization of culture and traditions'''''<br/>
Sustainable Tourism can also improve the preservation and transmission of [[Cultural values|cultural and historical traditions]]. Contributing to the conservation and sustainable management of natural resources can bring opportunities to protect local heritage or to revitalize native cultures, for instance by regenerating traditional arts and crafts.

'''''Encouragement social involvement and pride'''''<br/>
In some situations, tourism also helps to raise local awareness concerning the financial value of natural and cultural sites. It can stimulate a feeling of pride in local and national heritage and interest in its conservation. More broadly, the involvement of local communities in sustainable tourism development and operation seems to be an important condition for the sustainable use and conservation of the [[biodiversity]].

'''''Benefits for the tourists of Sustainable Tourism'''''<br/>
The benefits of sustainable tourism for visitors are plenty: they can enjoy unspoiled nature and landscapes, environmental quality of goods or services (clean air and water), a healthy community with low crime rate, thriving and authentic local culture and traditions.

==Sustainable Tourism Strategy==

The sustainable management of tourism is a complex managerial undertaking, requiring the involvement of multiple stakeholder groups, at local, regional and international levels. It entails a large set of actors and stakeholders, ranging from tour operators, industry associations and NGOs to local public authorities, businesses and independent small vendors. Indirectly, ‘producing holiday experiences’ involves entire communities and is subject to a multiplicity of motives, interests and perspectives<ref name=P23/>. In other words, the tourism economy consists of an entire network of institutional and business actors, that should be engaged in sustainable practices through rules and incentives.

Below a few steps are listed for the development and implementation of a strategy for sustainable tourism.

===Analysis of status-quo===
*Analysis of previous tourism management strategies for the specific area: What can be used? Has it been implemented? Which lessons are to be learnt?
*A [[stakeholder]] analysis: Who has an interest in sustainable tourism development? Who are the main actors?
*Facts and figures of the local educational system, economic and social structure
*Anecdotal and traditional knowledge

This information can be collected through
*Interviews with [[stakeholders]]
*Questionnaires distributed and collected by e-mail, fax or personally in order to compile standardised data and perform a statistical analysis
*Participation in focus group meetings (e.g. meetings on environmental education, [[biodiversity]] management, good governance and fisheries)
*Literature search (including the local library)

===Strategy development===
A Sustainable Tourism Strategy is based on the information collected. It defines the priority issues, the [[stakeholder]] community, the potential objectives and a set of methodologies to reach these objectives. These include:
*Conservation of specific coastal landscapes or [[habitats]] that make the area attractive or protected under nature conservation legislation
*Development of regionally specific sectors of the economy that can be interlinked with the [[tourism]] sector (e.g. production of food specialities and handicrafts)
*Maximising local revenues from tourism investments
*Enabling self-determined cultural development in the region, etc.

===Action plan===
The Action Plan describes the steps needed to implement the strategy and addresses a number of practical questions such as: which organizations will take up which activities, over what time frame, by what means and with which resources?
As the actions have to be considered on the basis of regional circumstances, there is no standard action plan for all. However, Action Plans usually include measures in the following fields:
*'''Administration:''' e.g. promotion of co-operation between sectors and of cross-sectorial development models; involving local people in drafting tourism policy and decisions
*'''Socio-economical sector:''' e.g. promoting local purchasing of food and building material; setting up networks of local producers for better marketing; development of new products to meet the needs of tourists, etc.
*'''Environment:''' e.g. improving control and enforcement of environmental standards (noise, drinking water, bathing water, waste-water treatment, etc.); identification and protection of endangered habitats; creation of buffer zones around sensitive natural areas; prohibition of environmentally harmful sports in jeopardised regions; strict application of [[Environmental Impact Assessment (EIA)]] and [[Strategic Environmental Assessment]] procedures on all tourism related projects and programs
*'''Knowledge:''' training people involved in coastal tourism about the value of historical heritage; environmental management; training protected area management staff in nature interpretation; raising environmental awareness among the local population; introducing a visitors information programme (including environmental information)

==Conclusions==
During the last century, the role of beaches has completely reversed: they have become the driving force behind economic welfare instead of just being an inhospitable place. Demographic pressure, excessive land use and related factors, both in the [[coastal hinterland|hinterland]] (e.g. river dams, water diversion) and on the beach itself (e.g. [[hard coastal protection structures]], sand/coral mining), have led to a general decrease in the contribution of [[sediments]] to the maintenance of the beaches and foreshores. It is hard to find a unique solution for all those problems. However, the following points are essential:
* The implementation of '''[[Integrated Coastal Zone Management (ICZM)|Integrated Coastal Zone Management]]'''
* A '''better dissemination of the existing information''' should be achieved. For that purpose, a better coordination of the existing governmental bodies that deal with coastal management is necessary
* '''Improvement of environmental education''' is a precondition for sustainable development of the coast

==See also==
===External links===
https://www.gstc.org/ The Global Sustainable Tourism Council (GSTC) is managing the GSTC Criteria, global standards for sustainable travel and tourism; as well as providing international accreditation for sustainable tourism Certification Bodies.

===Internal Links===
*[[Tourism]]
*[[Coastal pollution and impacts]]
*[[Threats to the coastal zone]]

==References==
<references/>

{{author
|AuthorID=16476
|AuthorFullName=Lal Mukherjee, Abir
|AuthorName=Lal Mukherjee, Abir}}

{{Review
|name=Job Dronkers|AuthorID=120|
}}

[[Category:Tourism]]
[[Category:Integrated coastal zone management]]

Marine Biotechnology in Portugal

2025-07-16T12:02:29Z

Admin: update URLs/domain marinebiotech

{{Marine Biotechnology
|Image=Image:Portugal map.gif
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{{template:Marinebiotech updated
|month_updated=August
|year_updated=2016
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== Overarching science strategies, plans and policies ==
Portugal has a National strategy for the Sea (ENM) for the period 2013-2012 (ENM_PT)<ref name="fcct">http://www.dgpm.mam.gov.pt/Documents/ENM.pdf</ref>
This strategy is a public policy instrument that presents a new development model for the ocean and offshores (blue growth) that points to a long-term, intelligent, sustainable and inclusive growth path, that intends to prepare Portugal to tackle the challenges brought by the growth, promotion and competitiveness of the Sea Economy, at both European and International levels.
This strategy lists a series of concrete measures and actions and one of the main intervention domains deals with the sustainable exploitation of living resources where it is expected that biotechnology will be a major instrument, in the sea food processing including fisheries and aquaculture, in the valorization of biomass and rest raw materials, leading to an impact in numerous industrial applications, such as food and feed, pharmaceutical, cosmeceutical, and others.

Recently “The Research & Innovation smart specialization strategy” (2014) (ENEI_PT)<ref name="ffct">https://www.fct.pt/esp_inteligente/index.phtml.en</ref>, written by FCT following the European Cohesion fund requirement, as a condition to be able to receive the EU structural 2014-2020 grants, reinforces these intentions, and identifies the Sea economy as one of the main priorities for Portugal.

'''Direcção geral da política do mar (DGPM)'''<ref name="fctt">http://www.dgpm.mam.gov.pt/Pages/eea_grants_quem_somos.aspx#4</ref>

DGPM mission is to develop, evaluate and update the National Strategy for the Sea, to elaborate, and propose political measures, to plan and regulate the maritime space in his different uses and activities, to follow-up and participate in the Maritime policy integrated in the EU and promote the national and international cooperation in maritime affairs.

'''COTEC Portugal''' <ref name="ffcct">http://www.cotecportugal.pt/</ref>
a business association for innovation has the mission to «promote the competitiveness of companies established in Portugal. COTEC led the elaboration of a document “Blue growth for Portugal” that analysis in detail the current state and perspectives for the six main maritime areas: 1.Food/feed from marine resources, 2.Offshore energy, 3.Equipment, repair and shipbuilding, 4. Leisure, tourism and recreation, 5.New uses and bioresources from the sea, 6. Ports and Maritime transport (see: Blue growth for Portugal)

== Research funding schemes and programmes ==

'''EU structural 2014-2020 grants '''

Out of the 15 EU grant Funding channels, one will be exclusively devoted to the Sea<ref name="portt">https://www.portugal2020.pt/Portal2020/Media/Default/Docs/Programas%20Operacionais/PO%20Mar%202020.pdf</ref>, with a focus on the promotion of competitive fisheries, aquaculture, aiming to an increase in commercialization and job creation.
Additionally, funding for marine Biotechnology will be transversal to many other regional and thematic funding programmes, currently or soon to open, under Portugal 2020 (for example, COMPETE 2020<ref name="pofc">http://www.pofc.qren.pt/</ref>, other regional programmes including the islands Azores and Madeira or bilateral funding).<ref name="portug">https://www.portugal2020.pt/Portal2020/programas-operacionais-portugal-2020-2)</ref>

'''Research Funding in Portugal'''

The funding of the Portuguese research system is mainly conducted under the authority of the '''Ministry of Education and Science''', namely through its '''Foundation for Science and Technology (FCT)'''. FCT is funding research via an annual non-thematic research programme which funds all research areas through competitive calls for proposals. The total funding budget for FCT is about 500 M EUR per year, with about € 0.5 - 1 M EUR being spent on marine biotechnology. FCT has signed with ANR (France) a collaboration protocol, with emphasis on Oceanology cooperation. However, this protocol has not been implemented yet.<ref name="fct">http://www.fct.pt/index.phtml.en</ref>

'''Other Research Funding Programmes'''

* Azores Marine Research Specific Programme managed by Direcção Regional da Ciência, Tecnologia e Comunicações <ref name="azo">http://www.azores.gov.pt/Portal/en/principal?lang=en&area=ct</ref>
* ON2 - North Portugal Regional Operational Programme 2007/2013 with two strategic priorities with special relevance to S&T: “Competitiveness, Innovation and Knowledge” and “Economic Valorisation of Specific Resources” with a specific objective related with Economic development of new uses for the sea and a significant investment in marine S&T infrastructures managed by a political management body <ref name="nov">http://www.novonorte.qren.pt/pt/menu-topo/english-version/</ref>
* Centro de C&T da Madeira - CITMA (language: Portuguese)
* Calouste Gulbenkian Foundation - FCG
* Fundação Oriente
* General Directorate of Fisheries and Aquaculture of the Azores (language: Portuguese)
* Luso-American Foundation - FLAD
* Regional Directorate for Science and Technology - DRCT (language: Portuguese)

'''Private funding mechanisms'''

There is no specific private funding exclusive to Marine Biotechnology, however Portugal has a venture capital market duly established that is capable of financing companies that bet on emerging sectors such as marine Biotechnology. The type of funds available include: seed, start-up, expansion and internationalization, tourism, sector specific and regional. Portugal Ventures<ref name="axzo">http://www.portugalventures.pt/</ref> is a Venture Capital Company, manages several Venture Capital & Private Equity funds with a total capital of around € 600 million. Its portfolio is made up of approximately 180 companies from a number of different industries. The aim is to improve the competitiveness of the Portuguese economy by investing in cutting edge industries and technologies, as well as in companies geared toward global markets.

'''Other entrepreneurship/innovation associations'''

* Associação Portuguesa de Business Angels<ref name="apdba">http://www.apba.pt</ref>
* Associação Portuguesa de Capital de Risco e de Desenvolvimento<ref name="apdcr">http://www.apcri.pt</ref>
* Agency for Innovation<ref name="afi">http://www.adi.pt/</ref>
* Agency for Innovation and Competitiveness (IAPMEI)<ref name="afiac">http://www.iapmei.pt/</ref>

== Forum / Clusters ==
'''Forum Empresarial da Economia do Mar (FEM)'''

''Entrepreneurial Forum for the Economy of the Sea''

The Business Forum of the Economy of the Sea<ref name="affiac">http://www.fem.pt/</ref>, is a business association: "Sea Economic Hypercluster", with the following objectives: a) contribute to the taking of the maritime economy as a national goal, in order to affirm Portugal as relevant maritime actor at the global level; b) contribute to the sustainable development of sea and appreciate its importance as a major economic resources, projecting it as the great engine of economic development of the country; c ) promote a common and integrated strategy of the activities related to the maritime economy, and create the conditions to promote good business practices, and cooperation between national strategic actors for the development of the Portuguese economy and the production of collective wealth in all business sectors related to the maritime economy. FEM launches a monthly newsletter.<ref name="weebly">http://feemar.weebly.com/publicadas.html/</ref>

'''Oceano XXI – Cluster do conhecimento da Economia do Mar'''

Association for the Knowledge and Economy of the Sea
Oceano XXI <ref name="oceano">http://www.oceano21.org</ref> is a private non-profit corporate body, created in 2009 by the initiative of two regional associations IDCEM (Instituto para o Desenvolvimento do Conhecimento e Economia do Mar) and AFM (Associação Fórum Mar Centro). The Association has more than 60 members, from different sectors of activity of the Sea Economy, between companies and business associations, R&D Centres, higher education institutions, local authorities and other associative organizations. <u>Oceano XXI mission:</u> To foster the "Sea Knowledge and Economy Cluster" through the intersection of knowledge and support for innovation, internationalization and entrepreneurship contributing in sustainability conditions for the country's competitiveness.

'''BlueBio Alliance'''

The BlueBio Alliance is a networking initiative that aims to accelerate the development of the whole value chain connected to Marine Biotechnology in Portugal including all relevant stakeholders. The Bluebio alliance wants to act in collaboration with other relevant and broader scope initiatives such as Oceano XXI.

== Law firms ==
<u>specialized in maritime affairs</u>
* '''Vieira de Almeida & Associados'''(VdA)<ref name="vdapt">http://www.vda.pt/en/what-we-do/sectors/Economy-of-the-Sea/9520/</ref>
VdA strives to deepen Portugal's knowledge and know-how on the Economy of the Sea and also to be able to mobilize other "maritime nations" of the world. VdA has created a specific multidisciplinary team providing specialised legal services in a number of matters of this innovative economy, such as: Business investment projects,Business plan structuring, Corporate and contractual relationships, Structuring supply and distribution models , Mergers, acquisitions, Regulatory and Public Procurement, Instruments of national maritime space planning, Conflicts between uses and activities developed in national maritime space, Shared uses of national maritime space, Privative uses of national maritime space (concessions, licences and authorizations), Environmental issues, Financing activities in the national maritime space, Intellectual property rights.

* '''Miranda Correia Amendoeira & Associadas'''<ref name="wwd">http://www.mirandalawfirm.com/?lang=pt</ref>

== Portals / Platforms ==

* '''Portal do Mar '''<ref name="pdm">https://www.portaldomar.pt/PortaldoMar/index.htm</ref>and '''Portal Maroceano'''<ref name="maroc">http://www.maroceano.pt/component/content/article/2037-blue-growth-for-portugal</ref> are portals that dedicate to constantly update and release maritime related news and online services.

* '''Plataforma Tecnologia do Mar de aveiro'''(PTUA)<ref name="ua">http://www.ua.pt/ptmar/</ref>
: This platform intends to promote collaborations between university and SMEs, with the intention to facilitate technology transfer, leading to an increase in business competitiveness.

== Research priorities for marine biotechnology research ==

n/a

== Strategic documents ==

n/a

== Infrastructures and coordination and support capacities / initiatives ==

* Portugal operates eight local/coastal vessels ranging from 11m to 31,40m (Águas Vivas, Arquipelago, Diplodus, NRP "Andromeda", NRP "Auriga", Puntazzo, Tellina and Ziphius); one regional vessels of 47,50m (Noruega); and two global vessels of 68,20m and 68,50m (NRP "Almirante Gago Coutinho" and NRP "D. Carlos I") registered in the European Research Vessels Infobase <ref name="eurocc">http://www.eurocean.org</ref>.

* Portugal maintains about 25 large marine research equipments registered in the European large Exchangeable instruments database <ref name="eur">http://www.eurocean.org</ref>.

* Key '''aquaculture experimental and research facilities''' in Portugal include
::* Experimental Research Facilities CIIMAR Portugal Land based facilities
::* Specialised Laboratories IPIMAR Portugal
::* Marine aquaculture station of Ramalhete University of Algarve Portugal
* Any other research facilities of relevance to Marine Biotech
::* Algarve Centre of Marine Sciences, University of Algarve
::* Centre of IMAR at Department of Oceanography and Fisheries at the University of the Azores

(For a complete description of the Portuguese Marine research infrastructures see: [http://www.eurocean.org/np4/20]

'''Research Centres / Capabilities'''

<u>Government Laboratories:</u>

Department of Marine Geology - INETI (language: Portuguese)

Fisheries and Sea Research Institute - IPIMAR (language: Portuguese)

Hydrographic Institute - IH (language: Portuguese)

National Laboratory of Civil Engineering - LNEC

Meteorological Institute

<u>Associated Laboratories:</u>

Centre for Environmental and Marine Studies - CESAM

Centre of Marine and Environmental Research - CIMAR

Institute for Systems and Robotics - IS

<u>R&D Units In Portugal:</u>

Biogeochemistry Group - IMAR

Centre for the Study of Hydrosystems - CEHIDRO

Centre for Ecological Modelling - IMAR

Centre of Marine Environment and Technology - MARETEC

Centre of Marine Sciences of Algarve - CCMAR (language: Portuguese)

Centro de Recursos Minerais, Mineralogia e Cristalografia - CREMINER

Centro de Investigação Marinha e Ambiental da Universidade do Algarve

Department of Oceanography and Fisheries of the University of Azores - DOP

Eco-Ethology Research Unit

Guia Marine Laboratory of Lisbon University - IMAR

Interdisciplinary Centre of Coimbra - IMAR

Institute of Marine Research - IMAR
Institute of Oceanography - IO

Wave Energy Centre

Underwater Systems and Technology Laboratory - Porto University

== Collaboration with European initiatives ==

* FCT is partner in the following European initiatives
::*JPI Oceans<ref name="jpi">http://www.jpi-oceans.eu</ref>
::*COFASP<ref name="cofas">http://www.cofasp.eu/</ref>
::*OCEAN ERA NET<ref name="oceanera">http://www.oceaneranet.eu/pages/new-page-5.html</ref>
::*CSA MarineBiotech<ref name="csa">https://www.vliz.be/projects/marinebiotech/</ref>
::*EurOcean<ref name="oce">http://www.eurocean.org</ref>

== Major observations, trends and future prospects ==
There is an industry forum for marine biotechnology. However, there is no specific program for funding marine biotechnology, hence marine biotechnology is fragmented and needs national cooperation.

== References ==
<references/>

{{Marinebiotechdisclaimer}}

Marine Biotechnology at Pan-European level

2025-07-16T11:46:00Z

Admin: update URLs/domain marinebiotech

Go back to: [[Portal:Marine Biotechnology|Home]] > [[Strategies, Policies and Programmes]]

{|Width = "100%"
|valign="top" Width = "60%" style="padding:10px 0px 0px 0px"| __TOC__
| style="padding:10px 0px 0px 0px"|[[Image:Europe carte.jpg|caption|right|400px]]
|}
<br><br>
== Situation ==

Covering over 50% of the territory of the European Union, the marine waters under European jurisdiction include four seas and two oceans stretch from the Arctic through the North Sea, Baltic, Atlantic, Mediterranean and Black Sea. In addition, European jurisdiction also includes the waters surrounding Europe’s ultra-peripheral regions, many of which are located in tropical latitudes with high biodiversity. The European landmass has a coastline of 74,000km which is equivalent to about eight times that of the USA and four times that of Russia. Hence, Europe is a truly maritime continent, with access to an enormous range of marine habitats from coastal lagoons, to inshore waters to shelf seas and the deep ocean.

The coasts, seas and oceans around Europe host a very diverse set of ecosystems and habitats ranging from coastal marshes to lagoons, bays, deepsea, polar and tropical marine environments, tropical and cold coral reefs, deep-sea anoxic sediments and brine lakes, continental margin cold seeps and mudvolcanoes, and coastal and deep-sea hydrothermal vents. These ecosystems, in turn, host an extraordinary biodiversity.

Europe’s seas and coasts are also important for the economy and employment. According to the European Commission , if we count all economic activities that depend on the sea, then the EU's blue economy represents 5.4 million jobs and a gross added value of just under €500 billion per year.

Europe has a long-standing tradition of marine bio-science research as well as a strong biotechnology expertise, and hosts significant research infrastructures relevant for marine biotechnology research and development. This includes one of the largest fleet of research vessels in the world, an extensive network of marine stations, some of which are among the oldest in the world, and world class biotechnology laboratories such as the European Molecular Biology Laboratory (EMBL) and associated bio-informatics infrastructures.

== Overarching regional science strategies, plans and policies ==

There is no overarching pan-European RTD policy, plan or strategy agreed among EU Countries and Associated Members States at the governmental level or at EC level specifically targeting Marine Biotechnology.

However, a substantial number of strategic documents have been developed over the years as a result of a wide range of science policy initiatives (see below). These culminated into a generally accepted vision and strategy for marine biotechnology research in Europe, published in 2010 by the European Marine Board, shared by at least by 34 Leading European Marine Science Organisations including a large number of national funding agencies (see Marine Board-ESF Position Paper 15 on Marine Biotechnology available from http://www.marineboard.eu/publications).

The EU research policy has responded to the growing interest in marine genetic resources to some extent, notably through support for the Marine Genomics and Marine Biodiversity (MarBEF) FP6 Networks of Excellence and other on-going collaborative projects. Recent efforts to support and coordinate European coastal and marine research infrastructures to improve, for example, access to research vessels, stations and laboratories indicate some level of recognition that action is needed to fully exploit the vast but fragmented research infrastructure available for marine sciences in Europe, including for Marine Biotechnology research.

== Research Funding Schemes and Programmes ==

Marine Biotechnology RTDI at pan-European level is funded through a range of instruments including

* EU Framework Programmes for Research. In FP7 this was done mainly under THEME 2 on Agriculture, Fisheries and Biotechnology as well as via cross-cutting calls under the “Oceans of Tomorrow” <ref name="cor">http://cordis.europa.eu/eu-funding-guide/home_en.html</ref>

* Structural funds <ref name="fun">http://ec.europa.eu/research/era/instruments/instruments/structural_funds_en.htm</ref>

* ESF EUROCORES<ref name="esf">http://www.esf.org/activities/eurocores.html</ref> which is currently being phased out.

* COST Actions<ref name="cos">http://www.cost.eu/domains_actions</ref> - A flexible, fast, effective and efficient tool to network and coordinate nationally funded research activities, bringing good scientists together under light strategic guidance. COST is based on networks centered around research projects in fields that are of interest to at least five COST countries.

* In the future, pan-European collaborations may also receive funding from a potential ERA-NET in Marine Biotechnology Research (as being developed by the CSA MARINEBIOTECH<ref name="mbi">https://www.vliz.be/projects/marinebiotech/</ref>) as well as under the framework of the Joint Programming Initiative on Healthy and Productive Seas and Oceans (JPI Oceans<ref name="jpi">http://www.jpi-oceans.eu</ref>).

== Research priorities ==

Marine Board-ESF Position Paper 15 on Marine Biotechnology together with the scoping paper of the EU KBBE-net Coordinated Working Group on Marine Biotechnology (CWG-MB) provide a comprehensive overview of the European research priorities for marine biotechnology research and identify some potential areas of common interest which might benefit from transnational cooperation in Europe.

'''Marine Board Position Paper 15 on Marine Biotechnology''' analysed the contributions Marine Biotechnology can make to address key societal challenges and identified the associated future research priorities. These are summarised in below table.

{| border="1" cellspacing="0" width="750px"
|+ '''Marine Biotechnology research priorities to address key societal challenges'''
! Target research area for development
! Research priorities and objectives
|-
| '''Food''': Development of food products and ingredients of marine origin (algae, invertebrates, fish) with optimal nutritional properties for human health.
| - Develop innovative methods based on -omics and systems biology for selective breeding of aquaculture species;
- Develop biotechnological applications and methods to increase sustainability of aquaculture production, including alternative preventive and therapeutic measures to enhance environmental welfare, sustainable production technologies for feed supply, and zero-waste recirculation systems;

- Integration of new, low environmental impact feed ingredients to improve quality of products and human health benefits.
|-
| '''Energy''': Development and demonstration of viable renewable energy products and processes, notably through the use of marine algae
| - Produce an inventory of microalgae resources for biofuel production to support optimisation of the most appropriate strains;
- Improve knowledge of basic biological functions, tools for steering the metabolism and cultivation methods of marine microalgae to improve the photosynthetic efficiency, enhance lipid productivity and obtain microalgae with optimum characteristics for mass cultivation (mixed & mono cultures), biofuel production and biorefinery;

- Develop efficient harvest, separation and purification processes for micro- and macro-algae.
|-
| '''Health''': Development of novel drugs, treatments and health and personal care products
| - Increase the focus on the basic research (taxonomy, systematics, physiology, molecular genetics and (chemical) ecology of marine species and organisms from unusual and extreme environments to increase chances of success in finding novel bioactives;
- Improve the technical aspects of the biodiscovery pipeline, including the separation of bioactives, bio-assays that can accommodate diverse material from marine sources, dereplication strategies and structure determination methods and software;

- Overcome the supply problem to provide a sustainable source of novel pharmaceutical and healthcare products through scientific advances in the fields of aquaculture, microbial and tissue culture, chemical synthesis and biosynthetic engineering.
|-
| '''Environment''': Development of biotechnological approaches, mechanisms and applications to address key environmental issues
| - Develop automated high-resolution biosensing technologies allowing in situ marine environmental monitoring to address coastal water quality, including prediction and detection of HABs and human health hazards;
- Develop cost-effective and non-toxic antifouling technologies combining novel antifouling compounds and surface engineering;

- Consolidate knowledge on DNA-based technologies for organism and population identification and support the development of commercial tools and platforms for routine analysis.
|-
| '''Industrial Products and Processes''': Development of marine derived molecules exploitable by industry including enzymes, biopolymers and biomaterials.
| - Develop enabling technologies for high throughput enzyme screening and for the expression of marine proteins and enzymes through dedicated hosts;
- Produce marine biopolymers as novel competitive commercial products in food, cosmetics and health.
|}

Marine Board Position Paper 15 further identified a number of Research and Development priorities associated with key marine biotechnological toolkits presented in table below.

{| border="1" cellspacing="0" width="750px"
|+ '''Marine Biotechnology toolkit research priorities'''
! Target research area for development
! Research priorities and objectives
|-
| '''Genomics and meta-genomics, molecular biology in life sciences'''
| - Implement genomic analyses of marine organisms, including the systematic sampling of different microorganisms (viruses, bacteria, archaea, pico and micro-plankton), algae and invertebrate taxa;
- Implement metagenomic studies of aquatic microbiomes and macrobiomes.
|-
| '''Cultivation of marine organisms'''
| - Develop enabling technologies for culture and isolation of uncultivated microorganisms;
- Develop innovative culture methods adapted to vertebrate or invertebrate cell lines for production of active compounds.
|-
| '''Bio-engineering of marine micro-organims'''
| - Optimise microalgal cultivation systems with respect to energy supply, productivity and cost;
- Develop innovative photobioreactors adapted to different species of interest and production sites;

- Promote research on the biorefinery approach based on microalgae production to develop a long-term alternative to petrochemistry.
|-
| '''Marine Model Organisms'''
| - Identify and prioritise new marine model organisms that are still not investigated in the tree of life and which are needed to fill critical knowledge gaps;
- Investigate identified marine model organism cultivation and perform genomic and chemical analysis.
|}

The '''EC KBBE-NET Coordinated Working Group on Marine Biotechnology (CWG-MB)''' made an inventory of ongoing and planned activities and fields of interest in Belgium, Denmark, France, Germany, Ireland, Norway, Turkey, United Kingdom which revealed substantial overlap in some areas and more scattered interests in others. Four specific areas of activity were identified as those most likely to benefit from a co-ordinated approach, giving possibilities for development on a fully-transeuropean scale. These are:

::* Marine bioprospecting/biodiscovery
::* Robust, biotechnology-based state of the art R&D tools and infrastructures tailored for marine biotechnology
::* Molecular aquaculture
::* Biomass production for bioenergy and fine chemicals

== Overview of key Marine Biotechnology Science Policy events and documents since 2000 ==

Marine biotechnology is recognised as being central in delivering on the potential of the oceans to contribute to the sustainable delivery of food, energy and biomaterials, as well as to improvements in environmental and human health. Scientists, policy makers and industry representatives have contributed to the development of this vision for marine biotechnology.

Below is an overview of the most important documents and recent events highlighting the relevance of marine biotechnology and providing key recommendations and guidance on how to develop a thriving European marine biotechnology sector<ref name="mie">Largely based on information overview available from the website of the Irish Marine Institute at http://www.marine.ie/home/research/SeaChange/NationalMarineBiotechnology/Marine+Biotechnology+Policy+Initiatives.htm</ref>.

* '''2011-2013 – CSA MARINEBIOTECH''' FP7 Coordination and Support action aiming to prepare the foundation for an ERA-NET in the area of marine biotechnology.<ref name="mbu">https://www.vliz.be/projects/marinebiotech/</ref>

* '''2012 –Communication from the European Commission on Blue Growth, opportunities for marine and maritime sustainable growth'''. The Communication identified Marine Biotechnology as one of five areas where additional effort at EU level could stimulate long-term growth and jobs in the blue economy, in line with the objectives of the Europe 2020 strategy.<ref name="mar">http://ec.europa.eu/maritimeaffairs/policy/blue_growth/documents/com_2012_494_en.pdf</ref>

* '''2010 - Marine Board-ESF Position Paper 15: Marine Biotechnology: a New Vision and Strategy for Europe'''<ref name="mbe">http://www.marineboard.eu/publications</ref>. This paper calls for the development of a European marine biotechnology strategy. In doing so, it highlights the potential of marine biotechnology to impact Europe’s economy and stresses the importance of including marine biotechnology topics in future Framework Programmes.

* '''2009 - EU KBBE-net Coordinated Working Group on Marine Biotechnology (CWG-MB)'''<ref name="nrr">http://www.marine.ie/NR/rdonlyres/B8CD4BDE-FE7B-4218-AB2F-DEDFE5421F9D/0/CWGMBtoKBBEnetreportdistributed.pdf</ref>. In this marine biotechnology scoping paper, EU member states identified marine research priorities to contribute to the structure of EU Framework Programme for Research and Technological Development.

* '''2008 - “Blue Book”''' from the EC-US Task Force on Biotechnology Research - Workshop - Principality of Monaco, 2008 <ref name="euu">http://ec.europa.eu/research/biotechnology/eu-us-task-force/index_en.cfm?pg=workshop_past</ref>. Microbes play an important role in the marine and indeed global ecosystem. The importance of developing marine genomics expertise, including the need for research to strengthen Europe’s bioinformatics research capability was the focus of this Task Force meeting.

* '''2007 - “The Bremen meeting”''' of European marine biotechnology experts, hosted by the German EU presidency<ref name="bre">http://www.marine.ie/NR/rdonlyres/813867B4-C1B6-4259-BE06-7B25C62815BF/0/37bremenmarinebiotechnologyresearch_en.pdf</ref>. Led by the European Commission and attended by representatives from industry and Europe’s marine biotechnology research community, this meeting highlighted the importance of the EU Framework Programme in supporting marine biotechnology research and called for the development of a European marine biotechnology research strategy.

* '''2006 - EC background paper no. 10 on Marine Biotechnology''' <ref name="ecb">http://www.marine.ie/NR/rdonlyres/C756DB2F-4A83-4E67-9C66-168A0EC17CCA/0/ECbackgroundpaperNo10onMarineBiotechnology2006.pdf</ref>. This paper recognised the commercial potential of marine biotechnology research in the development of different industry sectors, such as agriculture, health, food products, process engineering, environment and energy. It identified a range of commercial applications that marine biotechnology would support, including: biodiscovery; improving the production of marine organisms; novel products - both food and feedstock; and uses in diagnostics and biosensor applications.

* '''2005 – The CIRCA Report on Marine Biotechnology''' <ref name="cir">http://www.marine.ie/NR/rdonlyres/9FC1F9CA-5B8A-4442-A273-9B0C2060DDFE/0/CIRCA_2004.pdf</ref>. An Irish funded study providing an overview of marine biotechnology and makes recommendations about how Ireland could develop capabilities in marine biotechnology.

* '''2002 - US National Academy of Sciences published a report entitled Marine Biotechnology in the Twenty-first Century: Problems, Promise, and Products.'''

* '''2001 - ESF Marine Board Position Paper 4: A European Strategy for Marine Biotechnology'''<ref name="mbe">http://www.marineboard.eu/publications</ref>

Other (indirectly) relevant strategic documents which are relevant to Marine Biotechnology are:

* '''Europe 2020 - Europe’s economic growth strategy aiming at smart, inclusive and sustainable growth'''<ref name="opa">http://ec.europa.eu/europe2020/index_en.htm</ref>

* '''Bio-economy 2020''' - The European Commission adopted a strategy to shift the European economy towards greater and more sustainable use of renewable resources. The Commission's strategy and action plan, "Innovating for Sustainable Growth: a Bioeconomy for Europe", outlines a coherent, cross-sectoral and inter-disciplinary approach to the issue<ref name="eco">http://ec.europa.eu/research/bioeconomy/press/press_packages/index_en.htm</ref>.

* '''Innovation Union''' <ref name="inu">http://ec.europa.eu/research/innovation-union/index_en.cfm</ref>.

* '''Blue growth communication (2012)''' - EC Communication which launches a process to stimulate the blue economy. Marine Biotechnology is one of five focal areas<ref name="maf">
http://ec.europa.eu/maritimeaffairs/policy/blue_growth/index_en.htm</ref>.

* '''European Strategy for Marine and Maritime Research from the European Commission (2008)''' - The strategy among others highlights the need for marine biodiversity and biotechnology research and recognises their potential to contribute new knowledge for high value added products and processes<ref name="esm">http://ec.europa.eu/research/press/2008/pdf/com_2008_534_en.pdf</ref>.

== Major infrastructures coordination and support initiatives ==

* '''EC Expert Group on Marine Research Infrastructures (MRI)''' - The MRI Experts group was set up by the European Commission to identify key MRI needs and gaps and to improve governance at EU level. A Final Report is available from the website.<ref name="ece">https://webgate.ec.europa.eu/maritimeforum/taxonomy/term/401</ref>

* '''European Marine Biological Resource Centre (EMBRC)''' brings together 12 leading marine stations and EMBL to provide access to marine organisms (microbes, plants, animals) and newest techniques to the scientific community at large, including universities and industry. Medicines, blue energies (fuel made from algae) and many other end-products will be produced from the sea in the future, and EMBRC wishes to facilitate these discoveries.<ref name="emb">http://www.embrc.eu/</ref>

* '''Eurofleets (Towards an alliance of European Research fleets)''' is an FP7 Research Infrastructures Project aiming at bringing together the European research fleets to enhance their coordination and promote the cost effective use of their facilities.<ref name="fle">http://www.eurofleets.eu/np4/home.html</ref>

* '''Association of European Marine biological Laboratories (ASSEMBLE)''' is an FP7 Research Infrastructure Initiative comprising a network of marine research stations which aims to provide transnational access to a coastal marine ecosystems, research vessels, state-of-the-art experimental facilities and to a wide variety of marine organisms; either as research visits or by shipment. It also performs networking activities to enhance interoperability both within and outside of the ASSEMBLE network. This includes organizing workshops as well as establishing a virtual tool-box and a common database for marine organisms. Joint research is conducted to improve the provision of marine biological and/or ecological models with an emphasis on models for marine genomics.<ref name="ass">http://assemblemarine.org/</ref>

== Major science policy and coordination initiatives ==

* '''2011-2013 – CSA MARINEBIOTECH''' FP7 Coordination and Support action aiming to prepare the foundation for an ERA-NET in the area of marine biotechnology <ref name="eum">https://www.vliz.be/projects/marinebiotech/</ref>

* '''The Knowledge Based Bio-Economy Network (KBBE-NET)''' is a high-level expert group launched in 2006, with members from all EU Member States and Associated Countries to the Seventh Framework Programme (FP7). The main role of the KBBE-NET is to support the European Commission and EU Member States to achieve a coordinated approach for the development and implementation of a European research policy related to the Knowledge Based Bio-Economy (KBBE). It acts in coordination with the Standing Committee on Agricultural Research (SCAR). <ref name="kbb">http://ec.europa.eu/research/bioeconomy/policy/coordination/kbbe_net/index_en.htm</ref>

* '''MarBef+''' (completed in 2009) was an FP6 Network of Excellence (NoE) focused on marine biodiversity research funded by the European Union and consisting of 94 European marine institutes. The platform aimed to integrate and disseminate knowledge and expertise on marine biodiversity, with links to researchers, industry, stakeholders and the general public.<ref name="rbe">http://www.marbef.org</ref>

* '''Marine Genomics Europe (MGE)''' was an FP6 Network of Excellence (NoE) composed of 44 institutions from 16 countries (within and outside Europe) focussing on research using genomic to study marine organisms. The overarching aim of Marine Genomics Europe was to promote, develop and spread throughout the European Union a broad range of genomic approaches, to investigate a wide range of questions related to the functioning of marine ecysystems and to the biology of marine organisms.<ref name="nom">http://www.marine-genomics-europe.org/</ref>

* '''Marine Genomics for Users (MG4U)''' is an FP7 coordination action which aims to facilitate knowledge transfer, technology transfer, and technology translation between high-throughput marine genomics, industry and society. Marine genomics has enormous potential to improve our lifestyles and prosperity, and to assist with governance and sustainable management of the marine environment. However, many end users of marine genomics knowledge are not yet aware of how marine genomics hold great potential for problem solving and industrial commercial advantage. Valuable knowledge needs to be made accessible and disseminated in user friendly contexts. MG4U aims to spread results from recent and on-going projects in marine genomics and facilitate rapid, efficient knowledge transfer to generate interdisciplinary research capacity in Europe.<ref name="mgu">http://www.mg4u.eu/</ref>

* '''EuroMarine''' is a FP7 coordination and support action designed to bring together the three FP6 marine Networks of Excellence (NoE) communities; EUR-OCEANS, MarBEF and Marine Genomics Europe. In doing so, EuroMarine will provide a rich and diverse source of the best expertise and innovation available in European Marine Research, that can respond rapidly to societal needs, environmental demands, well-being and sustainability.<ref name="mcm">http://www.euromarineconsortium.eu</ref>

* '''Joint Programming Initiatives''':

::* '''Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI-OCEANS)''' is a coordinating and integrating platform of EU Member States and Associated Countries who invest in marine and maritime research. JPI Oceans will focus on making better and more efficient use of national research budgets, which represent 85% of the marine-maritime funding within Europe. One of the JPI’s goals is to develop joint research programs in which countries can be involved on a voluntarily basis (variable geometry). Participating countries will also decide what contribution to make: this may include institutional, project-related or new funds. Among different cross-cutting topics identified by the JPI Oceans, particular attention will be paid to further advance in the development of marine biotechnologies for the discovery of new products, including new drugs and antibiotics derived from marine organisms. Therefore, it is expected that the JPI Oceans will have a main role on the development of new medical products to combat antimicrobial resistance. In this sense strong synergies will be generated between the JPI Oceans and the JPI The microbial challenges.<ref name="jpi">http://www.jpi-oceans.eu</ref>

::* '''Joint Programming Initiative on Agriculture Food Security and Climate Change (FACCE)'''<ref name="cce">http://www.faccejpi.com/</ref>

::* '''Joint Programming Initiative on A Healthy Diet for a Healthy Life (HDHL)'''<ref name="hdl">https://www.healthydietforhealthylife.eu/</ref>

::* '''Joint Programming Initiative on Antimicrobial Resistance (AMR)'''<ref name="amr">http://www.jpiamr.eu/</ref>

* '''European Research Area Networks (ERA-NETs)'''. There are a number of ERA-NETs which have relevance for Marine Biotechnology research and development. These include:

::* '''SEAS-ERA''' (2010-2014) is a partnership of the leading Marine RTD Funding Organizations in 18 countries aiming at coordinating national and regional marine RTD activities. While not the sole focus of the SEAS-ERA Project, marine biotechnology has a role within their activities and identified as one of the high potential research areas of strategic importance for several of the European sea basins.<ref name="npf">http://www.seas-era.eu/np4/homepage.html</ref>

::* '''ERA-IB2''' is an ERA-NET in industrial biotechnology (IB) involving 19 partners, which builds on the success of the FP6 project ERA-IB and develops the network further into a pan-European approach to IB R&D funding. ERA IB2 defines industrial biotechnology much in the same way as the CSA MarineBiotech defines marine biotechnology, as the toolbox of biotechnology used to solve industrial issues. The definition of ERA-IB2 does not exclude these industrial issues to be marine related, and as such, may include support to marine biotechnology research. However, the industrial area covered by ERA-IB2 is vast, and so far issues related to marine biotechnology have not been in focus for the calls that have been issued.<ref name="aib">http://www.era-ib.net</ref>

::* '''EurotransBio''' is an international funding initiative supported by European program owners. It has established itself as the preferred funding instrument for small and medium sized enterprises (SMEs), collaborating in the area of modern biotechnology.<ref name="tra">http://www.eurotransbio.eu/</ref>

::* '''BIODIVERSA''' is a network of national funding organisations promoting pan-European research that offers innovative opportunities for the conservation and sustainable management of biodiversity <ref name="div">http://www.biodiversa.org/</ref>

::* '''ERASynBio''' - ERA-NET on Synthetic Biology<ref name="syn">http://www.erasynbio.eu/</ref>project

::* '''SUSFOOD''' - ERA-NET on Sustainable Food Production<ref name="sus">http://www.susfood-era.net/</ref>

::* '''SAFEFOOD''' ERA – European Excllence in food safety research programming<ref name="era">http://www.safefoodera.net/</ref>

::* '''ANIHWA''' – ERA-NET on Animal Health and Welfare<ref name="hwa">http://www.anihwa.eu</ref>

::* '''ERA ARD II''' – ERA-NET on Agricultural Research for Development<ref name="ard">http://www.era-ard.org</ref>

::* '''ERASysBio''' - ERA-NET Plus on Systems Biology<ref name="sys">http://www.erasysbio.net/</ref>

::* '''ERA-NanoSci''' ERA-NET on Nanosciences

::* '''ERA-NET BIOENERGY'''<ref name="oen">http://www.eranetbioenergy.net/website/exec/front</ref>

* '''ERA-NET PLATFORM''' is not an ERA-NET itself but, as the name suggests, a platform set up by ERA-IB-2 with and for ERA-Nets related to Industrial Biotechnology and innovative technologies, as well as the European Commission/DG Research and Innovation and the ETP SusChem/IB. The platform has the following objectives: (i) Exchange of information and experiences; (ii) Alignment of relevant activities; and (iii) Strengthen the collaboration between initiatives.<ref name="net">http://www.era-ib.net/era-net-platform</ref>

* '''European Technology Platforms (ETPs)''' are industry-led stakeholder fora charged with defining research priorities in a broad range of technological areas. They are characterised by addressing challenging issues for growth, embodying major technological advances in the medium to long term, creating community added-value, involving high research intensity and requiring an European approach. They are driven by industry, compared with ERA-Nets, which are driven by research funding agencies. In the Knowledge-Based Bio-Economy (KBBE) sector, five ETPs of the total 9 are directly or indirectly relevant for marine biotechnology and utilisation of marine bioresources:

::* '''Sustainable Chemistry Technology Platform (SusChem TP)''' for industrial biotechnology

::* '''European Biofuels Technology Platform (Biofuels TP)''' has an Algae fuels task force

::* '''European Aquaculture Technology and Innovation Platform (EATIP)'''

::* '''European Technology Platform ‘Food for Life’ (Food for Life TP)'''

::* '''European Technology Platform ‘Plants for the Future’ (Plant TP)''' – many aspects applicable to marine algae

::* An ETP that grouped the biological platforms together, the '''Bio-Economy Technology Platforms (BECOTEPS)''', has produced a final paper The European Bioeconomy in 2030, which is also relevant.

== Major Research initiatives ==

For more information about these iniciatives, please follow this link [https://www.vliz.be/projects/marinebiotech/imis.php?module=institute] to the MARINEBIOTECH database.

== Sources ==

* European Commission, COM(2012) 473 final, Green Paper on Marine Knowledge 2020 - from seabed mapping to ocean forecasting, Brussels, 29.8.2012 - available at http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=COM:2012:0473:FIN:EN:PDF
* Calewaert, J.-B.; Dixon, B.; Jaspers, M.; McDonough, N. (2011). A new dawn for marine biotechnology in Europe Biotechnol. Adv. 29(5): 453-456.
* European Commission, COM(2012) 494 final, Blue Growth - opportunities for marine and maritime sustainable growth, Brussels, 13.9.2012 - available at http://ec.europa.eu/maritimeaffairs/policy/blue_growth/documents/com_2012_494_en.pdf
* Marine Board Position Paper 15 Marine Biotechnology: A New Vision and Strategy for Europe
* EC Collaborative Working Group on Marine Biotechnology (CWG-MB) Scoping paper – available at http://ec.europa.eu/research/bioeconomy/pdf/cwg-mb_to_kbbenet_report_final.pdf
* Various EC Interim Catalogues of FP Projects, among others on Marine and Biotechnology research available at http://ec.europa.eu/research - for Theme to http://ec.europa.eu/research/bioeconomy/pdf/cwg-mb_to_kbbenet_report_final.pdf
* DG MARE ATLAS of the Sea - available at http://ec.europa.eu/maritimeaffairs/atlas/index_en.htm
* Marine Biotechnology in the European Research Area: Challenges and Opportunities for Europe. Book of Abstracts. Final CSA MarineBiotech conference. Royal Flemish Academy of Belgium for Science and the Arts, Brussels, Belgium, 11-12 March 2013. VLIZ Special Publication 64. Available from https://www.vliz.be/projects/marinebiotech/library.html

== References ==
<references/>

== Disclaimer ==

{{Marinebiotechdisclaimer1}}

Species lists

2023-09-06T10:47:32Z

Admin: update links

Information about species is important. Knowing what species exist, where and how they live, how they grow and interact, helps us understand patterns of change, and provides better knowledge of how to change our behaviour to support our fragile biodiversity.

Scientists have so far (2010) described an estimated 1.8 million species of animals, plants, fungi and other organisms. Millions more are believed to exist. Their interactions ensure functioning ecosystems in oceans, freshwater and on land. Many of these may disappear before they have even been named, as climate change, land-use change and other factors take their toll.

There exist already several “Global Species Information Systems". A “Global Species Information System” aims at gathering and making available information on all known species on earth and which serves as a tool for information and awareness raising for the wider public as well as for enhanced scientific cooperation.

An overview of some species lists:

==Global initiatives for species lists==

Marine:

* Marinespecies.org (http://www.marinespecies.org/)
* SeaLifeBase (http://www.sealifebase.org)

Marine and terrestrial:

* Integrated Taxonomic Information System (ITIS) (http://www.itis.gov)
* Species2000 (http://www.sp2000.org/)
* Species2000 + ITIS: Catalogue of Life (http://www.catalogueoflife.org)
* Wikispecies (http://species.wikimedia.org/)

==European initiatives for species lists==

Marine:
* European Register of Marine Species (ERMS) (http://www.marbef.org/data/erms.php)

Marine and terrestrial:
* Euromed plant base (http://www.emplantbase.org)
* Fauna Europaea (http://www.faunaeur.org)

==Regional marine initiatives for species lists==

Marine:
* https://www.marinespecies.org/rams/
* http://www.vliz.be/vmdcdata/narms/
* http://www.marinespecies.org/afremas/
<gallery>
Image:narms.jpg|'''North Atlantic Register for Marine Species'''
Image:masdea.jpg|'''Marine Species Database for Eastern Africa (MASDEA)'''
Image:scarmarbin.jpg|'''SCAR-Marine Biodiversity Information Network (SCAR-MarBIN) Webportal'''
</gallery>

==Species-specific initiatives for species lists==

Marine:
* http://www.fishbase.org
* http://www.algaebase.org/
* http://www.marinespecies.org/porifera/
* https://www.marinespecies.org/turbellarians/
* http://nemys.ugent.be/
* http://www.marinespecies.org/cumacea/
* http://www.marinespecies.org/pycnogonida/
<gallery>
Image:fishbase.jpg|'''Fishbase'''
Image:algaebase.jpg|'''Algaebase'''
Image:porifera.jpg|'''Porifera World Database'''
Image:proseriata.jpg|'''World database of Proseriata and Kalyptorhynchia - Rhabditophora'''
Image:hexacoral.jpg|'''Hexacorallians of the World'''
Image:nemys.jpg|'''World database of Mysids and nematodes - Nemys'''
Image:cephbase.jpg|'''A database-driven web site on all living cephalopods'''
Image:cumacea.jpg|'''World database of Cumacea'''
Image:pycno.jpg|'''World database of Pycnogonida'''
</gallery>

==Other initiatives for species lists==

===Information pages by aggregating all known data about every living species===

Marine and terrestrial
* Encyclopedia of Life (EoL) (http://www.eol.org/).
* WikiSpecies: (http://species.wikimedia.org)

===Systems for biogeographic information on marine organisms===

Marine:
* EurOBIS (http://www.eurobis.org)
* OBIS Ocean Biogeographic Information System (http://www.obis.org/)

===Systems for global biodiversity information===
Marine and terrestrial:
* GBIF Global Biodiversity Information System (http://www.gbif.org/)
* Biodiversity Heritage Library (BHL) (http://www.biodiversitylibrary.org

==References==
<references/>

[[Category:Coastal and marine ecosystems]]
[[Category:Marine Biodiversity‏‎]]

{{author
|AuthorID=8091
|AuthorName=simon
|AuthorFullName= Claus, Simon}}

Portal:Contents/Portals

2023-06-20T10:39:33Z

Admin:

==Portals==

Project-specific portals are part of the Coastal and Marine Wiki. At the moment the following portals are available:
{| class="plainlinks"
|valign="top"|[[Image:encora_port.jpg|200px|thumb|link=ENCORA_portal|[[ENCORA_portal|Portal on SoA European Coastal Research (ENCORA)]]]]
|valign="top"|[[Image:marbef_port.jpg|thumb|200px|link=http://www.marbef.org/wiki/Portal:Marine_Biodiversity|[http://www.marbef.org/wiki/Portal:Marine_Biodiversity Portal on Marine Biodiversity (MarBEF NoE)]]]
|valign="top"|[[Image:Portal euromarine.png|thumb|200px|link=http://www.coastalwiki.org/wiki/Portal:Euromarine|[http://www.coastalwiki.org/wiki/Portal:Euromarine Portal with information from three marine FP6 networks]]]
|-
|valign="top"|[[Image:spicosa_port.jpg|200px|link=http://www.coastalwiki.org/spicosa/Portal:SPICOSA|thumb|[http://www.coastalwiki.org/spicosa/Portal:SPICOSA Portal on Science - Policy Integration for Coastal System Assessment (SPICOSA)]]]
|valign="top"|[[Image:tox_port.jpg|thumb|link=Portal:Ecotox|200px|right|[[Portal:Ecotox|Portal on Marine Ecotoxicology]]]]
|valign="top"|[[Image:Portal_marine_biotech.jpg|link=Portal:Marine_Biotechnology|thumb|200px|[[Portal:Marine_Biotechnology|Portal on Marine Biotechnology]]]]
|-
|valign="top"|[[Image:theseus_port.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:THESEUS|200px|[http://www.coastalwiki.org/wiki/Portal:THESEUS Portal on Innovative technologies for safer European coasts in a changing climate (THESEUS)]]]
|valign="top"|[[Image:Pegaso.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:PEGASO|200px|[http://www.coastalwiki.org/wiki/Portal:PEGASO Portal on People for Ecosystem Based Governance in Assessing Sustainable Development of Ocean and Coast (PEGASO)]]]
|valign="top"|[[Image:Mermaid.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:MERMAID|200px|[http://www.coastalwiki.org/wiki/Portal:MERMAID Innovative Multi-purpose offshore platforms: planning, design and operation (MERMAID)]]]
|-
|valign="top"|[[Image:GIFS_portal.png|thumb|link=http://www.coastalwiki.org/wiki/Portal:GIFS|200px|[http://www.coastalwiki.org/wiki/Portal:GIFS Portal on the Geography of inshore Fishing and Sustainability (GIFS)]]]
|valign="top"|[[Image:Portal_eutrophication.png|thumb|link=Portal:Eutrophication|200px|[[Portal:Eutrophication|Portal on Eutrophication]] ]]
|
|}

Portal:Contents/Portals

2023-06-20T10:35:52Z

Admin:

==Portals==

Project-specific portals are part of the Coastal and Marine Wiki. At the moment the following portals are available:
{| class="plainlinks"
|valign="top"|[[Image:encora_port.jpg|200px|thumb|link=ENCORA_portal|[[ENCORA_portal|Portal on SoA European Coastal Research (ENCORA)]]]]
|valign="top"|[[Image:marbef_port.jpg|thumb|200px|link=http://www.marbef.org/wiki/Portal:Marine_Biodiversity|[http://www.marbef.org/wiki/Portal:Marine_Biodiversity Portal on Marine Biodiversity (MarBEF NoE)]]]
|valign="top"|[[Image:Portal euromarine.png|thumb|200px|link=http://www.coastalwiki.org/wiki/Portal:Euromarine|[http://www.coastalwiki.org/wiki/Portal:Euromarine Portal with information from three marine FP6 networks]]]
|-
|valign="top"|[[Image:spicosa_port.jpg|200px|link=http://www.coastalwiki.org/spicosa/Portal:SPICOSA|thumb|[http://www.coastalwiki.org/spicosa/Portal:SPICOSA Portal on Science - Policy Integration for Coastal System Assessment (SPICOSA)]]]
|valign="top"|[[Image:tox_port.jpg|thumb|link=Portal:Ecotox|200px|right|[[Portal:Ecotox|Portal on Marine Ecotoxicology]]]]
|valign="top"|[[Image:Portal_marine_biotech.jpg|link=Portal:Marine_Biotechnology|thumb|200px|[Portal:Marine_Biotechnology|Portal on Marine Biotechnology]]]
|-
|valign="top"|[[Image:theseus_port.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:THESEUS|200px|[http://www.coastalwiki.org/wiki/Portal:THESEUS Portal on Innovative technologies for safer European coasts in a changing climate (THESEUS)]]]
|valign="top"|[[Image:Pegaso.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:PEGASO|200px|[http://www.coastalwiki.org/wiki/Portal:PEGASO Portal on People for Ecosystem Based Governance in Assessing Sustainable Development of Ocean and Coast (PEGASO)]]]
|valign="top"|[[Image:Mermaid.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:MERMAID|200px|[http://www.coastalwiki.org/wiki/Portal:MERMAID Innovative Multi-purpose offshore platforms: planning, design and operation (MERMAID)]]]
|-
|valign="top"|[[Image:GIFS_portal.png|thumb|link=http://www.coastalwiki.org/wiki/Portal:GIFS|200px|[http://www.coastalwiki.org/wiki/Portal:GIFS Portal on the Geography of inshore Fishing and Sustainability (GIFS)]]]
|valign="top"|[[Image:Portal_eutrophication.png|thumb|link=Portal:Eutrophication|200px|[[Portal:Eutrophication|Portal on Eutrophication]] ]]
|
|}

Overzichtslijst beleidsinstrumenten

2021-03-24T12:08:44Z

Admin: Add warning: niet langer bijgewerkt...

{{Box Note|boxtype=warning|Note text=Deze pagina wordt niet langer bijgewerkt. Meer recente info is te vinden op http://www.vliz.be/niet-inheemse-soorten|http://www.vliz.be/niet-inheemse-soorten }}

<div style="float:right;width:400px;padding:0.4em 1em 0em 0.5em">
<div style="text-align: center;border:1px solid #00C4C7">
[[Niet-inheemse soorten Belgisch deel Noordzee en aanpalende estuaria| --> Naar de intropagina <--]]<br>
[[Lijst_niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria|--> Naar lijst niet-inheemse soorten <--]]<P><span class="plainlinks">
[http://www.vliz.be/vmdcdata/berms/ --> Naar Belgisch register van mariene en kustsoorten <--]
</div></div>

Op deze pagina wordt een overzicht gegeven van de beleidsinstrumenten die aandacht hebben voor de problematiek omtrent niet-inheemse mariene soorten. Een geactualiseerde lijst - met informatiefiches van de niet-'streek-eigen' mariene en kustgebonden soorten in het Belgische deel van de Noordzee en aanpalende estuaria - kan eveneens op deze pagina's geraadpleegd worden.

===Globale verdragen en akkoorden===
<br><span class="plainlinks">
1) Het [http://www.cbd.int '''Verdrag inzake Biologische Diversiteit'''] (Convention on Biological Diversity, CBD, afgesloten in 1992, van kracht sinds 1993) is een overeenkomst om actie te ondernemen op specifieke punten in verband met biodiversiteit, waaronder de opzettelijke en niet-opzettelijke introductie van niet-inheemse soorten.

Artikel 8 van de conventie stelt dat "''ondertekenende partijen, voor zover mogelijk en op passende wijze, de introductie van niet-inheemse soorten dienen te voorkomen en niet-inheemse soorten die ecosystemen, habitats of soorten bedreigen, dienen te bestrijden of uit te roeien''".

De bijeenkomst van de partijen in Nagoya (COP10, oktober 2010) stelde als doelstelling om - tegen 2020 - invasieve niet-inheemse soorten en hun verspreidingskanalen te identificeren, prioriteiten te stellen in de controle en uitroeiing van prioritiaire soorten en maatregelen te treffen voor het beheer van verspreidingskanalen zodoende de introductie en de inburgering van niet-inheemse soorten te vermijden. Meer dan 180 landen hebben het verdrag ondertekend. Het verdrag werkt op basis van juridisch bindende overeenkomsten. Informatie over niet-inheemse soorten in de context van de CBD is beschikbaar via het [http://www.cbd.int/invasive/ "Alien Species Portal"].

2) Het [http://www.cms.int '''Verdrag inzake Migrerende Wilde Diersoorten'''] (Convention on Migratory Species of Wild Animals, CMS of Verdrag van Bonn, afgesloten in 1979, van kracht sinds 1983) is gericht op de bescherming van migrerende terrestrische en mariene soorten en vogels in hun hele verspreidingsgebied.

Trekkende soorten waarvoor een internationale samenwerking wenselijk of noodzakelijk is, zijn opgenomen in bijlage II van het verdrag. Exoten die de trekkende soorten zoals opgenomen in bijlage II van de CMS in gevaar kunnen brengen, kunnen volgens het CMS aan controle worden onderworpen. Artikel III, 4c. stelt dat de partijen zich ertoe verbinden een strikte controle uit te voeren op de introductie van, of het terugdringen of uitroeien van reeds geïntroduceerde exotische soorten die de doelsoorten opgenomen in de bijlage I van dit verdrag op hun grondgebied dreigen in gevaar te brengen. Artikel V, 5 bepaalt dat de lidstaten in overeenkomst met de bepalingen van de bijlage II moeten voorzien in ''"Behouden en waar nodig en mogelijk, herstellen van de habitats van belang in het behoud van een gunstige staat van instandhouding, en het beschermen van deze habitats tegen verstoringen, waaronder een strikte controle van de introductie van, of controle van reeds geïntroduceerde, exotische soorten die schadelijk zijn voor de trekkende soorten"''

3) Het [http://www.cites.org '''Verdrag inzake internationale handel in bedreigde soorten'''] (Convention on International Trade in Endangered Species of Wild Fauna and Flora, CITES of Washington Convention, afgesloten in 1973, van kracht sinds 1975) regelt de handel in bedreigde dieren en planten, evenals daarvan afgeleide producten, tussen 172 aangesloten landen. Het verdrag werkt met 3 bijlagen, afhankelijk van de graad van bescherming in het land van uitvoer.

De Bijlage I lijst bedreigde dieren en planten op die direct met uitsterven bedreigd zijn (bv. walvissen, dolfijnen, … bepaalde orchideeënsoorten) en waarvoor geen handel toegestaan wordt. De soorten opgenomen in de Bijlage II zijn deze die mogelijks met uitsterven worden bedreigd, en waarvoor een CITES vergunning vereist is voor in- en uitvoer. De Bijlage III bevat alle dieren en planten die in minstens één land worden beschermd en waarvoor bilaterale handelsakkoorden bestaan. Relevant voor de problematiek van niet-inheemse soorten is een bepaling in Artikel XIV a waaronder het aan de partijen toegelaten is nationale maatregelen te treffen met betrekking tot soorten die niet in de CITES Bijlagen opgenomen zijn. Het is via deze bepaling dat EU lidstaten bepaalde exotische soorten behandelen.

4) Het [http://www.imo.org/OurWork/Environment/BallastWaterManagement/Pages/BWMConvention.aspx '''Internationaal Verdrag voor de Controle en het Beheer van Ballastwater en Sediment van de Scheepvaart'''] (ook IMO Ballastwater Conventie, International Convention for the Control and Management of Ships' Ballast Water and Sediments, BWM Convention, afgesloten in 2004) is gericht op de inspanningen die noodzakelijk zijn om te voorkomen dat schadelijke aquatische organismen via ballastwater en sedimenten verspreid worden.

Om de introductie van niet-inheemse soorten via de ballasttanken van schepen tegen te gaan verplicht de [http://www.imo.org/OurWork/Environment/BallastWaterManagement/Pages/BWMConvention.aspx IMO Ballastwater Conventie] schepen om een "Ballast Water and Sediment Management Plan" op te stellen en een "Ballast Water Record Book" aan boord te hebben waarin alle ballastoperaties worden bijgehouden. Daarnaast dient het beheer van het ballastwater te gebeuren volgens standaardprocedures ([http://www.imo.org/OurWork/Environment/BallastWaterManagement/Pages/BWMGuidelines.aspx zie website IMO]). Een derde element in de conventie betreft ballastwater uitwisseling ("Ballast Water Exchange") op zee, die bij voorkeur voorbij de 200 zeemijl van het vasteland plaatsvindt. Indien dit niet mogelijk is, moet de uitwisseling van ballastwater in ieder geval verder dan 50 zeemijl uit de kust plaatsvinden en dit in water van minstens 200 meter diep. In afwachting van de ratificatie van deze conventie wordt aangeraden door OSPAR om bepaalde maatregelen met betrekking tot het ballastwater van schepen reeds op een vrijwillige basis na te leven ([http://www.ospar.org/v_measures/get_page.asp?v0=10-07e__Ballast_Water_Guidance.doc&v1=5 OSPAR general guidance 07/2010]). Voorafgaand aan de IMO Ballastwater Conventie gaf de IMO resolutie ([http://www.vliz.be/imis/imis.php?module=ref&refid=115831 A.868(20)]) uit 1997 richtlijnen voor de controle en behandeling van ballastwater teneinde de overdracht van schadelijke organismen te beperken.

5) Het [http://www.un.org/Depts/los/convention_agreements/convention_overview_convention.htm '''UNCLOS Verdrag'''] van de Verenigde Naties (United Nations Convention on the Law of the Sea, UNCLOS, afgesloten in 1982, van kracht sinds 1994) verplicht de lidstaten ertoe het mariene milieu in de zeegebieden onder hun rechtsbevoegdheid te beschermen en te vrijwaren van "significante en schadelijke wijzigingen" als gevolg van de (on)opzettelijke introductie van niet-inheemse soorten.

Artikel 196 (1) van het Verdrag meldt dat: "''staten alle noodzakelijke maatregelen moeten treffen voor de reductie, preventie en controle van vervuiling van het mariene milieu als resultaat van het gebruik van technologieën of de (on)opzettelijke introductie van nieuwe of niet-inheemse soorten in bepaalde delen van het mariene milieu, dewelke daar schadelijke gevolgen kunnen veroorzaken.''"

6) Het [http://untreaty.un.org/ilc/texts/instruments/english/conventions/8_3_1997.pdf '''Verdrag m.b.t. de wet van het niet aan scheepvaart gebonden gebruik van internationale waterlopen'''] (Convention on the Law of Non-navigational Uses of International Watercourses, afgesloten in 1997, nog niet van kracht wegens onvoldoende ratificaties).

In artikel 22 van het verdrag verbinden lidstaten zich tot het treffen van “''alle noodzakelijke maatregelen ter preventie van de introductie van niet-inheemse of nieuwe soorten die significante negatieve effecten kunnen veroorzaken in het ecosysteem van de waterlopen, en als gevolg hiervan schade berrokkenen aan een andere staat''”.

7) Het [http://www.ramsar.org '''Ramsar Verdrag'''] (Ramsar Convention, afgesloten in 1971, van kracht sinds 1975) beoogt het behoud en het rationeel gebruik van alle "wetlands" door lokale, regionale en nationale acties en internationale samenwerking, als bijdrage tot een duurzame ontwikkeling. In het Ramsar Verdrag werden invasieve soorten geïdentificeerd als één van de bedreigingen voor ‘wetlands’.

8) Het [http://www.ippc.int '''Internationaal Verdrag voor de Bescherming van Plantensoorten'''] (International Plant Protection Convention, IPPC, afgesloten in 1951, van kracht sinds 1952, gewijzigd in 1987) is een international verdrag met betrekking tot fytosanitaire afspraken, incl. plagen van wieren en de indirecte gevolgen ervan.

Het IPPC organiseerde een [http://www.ippc.int/IPP/En/Archive/IAS2003/IAS-WORKSHOP-Home.htm workshop over invasieve niet-inheemse soorten] in 2003. In aansluiting met dit verdrag melden we ook het Akoord met betrekking tot Sanitaire en Fytosanitaire Maatregelen ([http://www.wto.org/english/docs_e/legal_e/15-sps.pdf Agreement on the Application of Sanitary and Phytosanitary Measures SPS], afgesloten in 1994, van kracht sinds 1995). Hoewel dit akkoord niet specifiek gericht is op niet-inheemse soorten, zijn vele plagen van oorsprong niet-inheems. </span>
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===Europese richtlijnen en regelgeving===
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1) De EU [http://ec.europa.eu/environment/nature/legislation/birdsdirective/index_en.htm '''Vogelrichtlijn'''], VRL (Council Directive 79/409/EEC of 2 April 1979 on the conservation of wild birds, afgesloten en van kracht sinds 1979) biedt een kader voor het behoud en beheer van wilde vogelpopulaties in Europa, en algemene richtlijnen met betrekking tot niet-inheemse vogelsoorten.

Artikel 11 van de HRL bepaalt dat lidstaten erover moeten waken dat introductie van niet-inheemse vogelsoorten geen negatieve effecten met zich meebrengt voor de lokale fauna en flora.

<span class="plainlinks">
2) De EU [http://ec.europa.eu/environment/nature/legislation/habitatsdirective/index_en.htm '''Habitatrichtlijn'''], HRL (Council Directive 92/43/EEC of 21 May 1992 on the conservation of natural habitats and of wild fauna and flora, afgesloten en van kracht sinds 1992) streeft het behoud van de biodiversiteit in de Lidstaten na, door middel van een gemeenschappelijk kader voor het behoud van wilde flora en fauna en habitats van gemeenschappelijke belang voor de EU.

De kaderrichtlijn richt een ecologisch netwerk in van beschermde gebieden, gekend als het ‘Natura 2000’ netwerk. De HRL maakt deel uit van de uitvoering van het Verdrag inzake Biodiversiteit (CBD) op Europees niveau. Artikel 22 b van de HRL bepaalt dat Lidstaten de opzettelijke introductie van niet-inheemse soorten in het wild op dergelijke wijze moeten inperken dat er geen negatieve gevolgen zijn voor de natuurlijke habitats en hun fauna en flora, en dat – indien nodig – dergelijke introducties verboden worden.

<span class="plainlinks">
3) De [http://europa.eu/legislation_summaries/customs/l11023_en.htm '''richtlijn Nr 338/97 van de Europese Raad betreffende de bescherming van wilde fauna en flora soorten door middel van de handel in deze soorten'''] (Council Regulation (EC) No 338/97 on the protection of species of wild fauna and flora by regulating trade therein, afgesloten in 1996, van kracht sinds 1997, gewijzigd in 2003) is de vertaling van het CITES Verdrag naar Europese wetgeving.

Deze richtlijn werd gewijzigd op 18 augustus 2003 door de [http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2003:215:0003:0084:EN:PDF richtlijn Nr 1497/2003]. De annexen van deze nieuwe richtlijn verwijzen naar een aantal niet-inheemse soorten die een bedreiging vormen voor importerende lidstaten. CITES is als regelgeving echter beperkt tot de opzettelijke introducties gezien het gebaseerd is op een systeem met toestemming. In artikel IV, 6D van de richtlijn 338/97 wordt expliciet vermeldt dat de Europese Commissie beperkingen kan opleggen aan bepaalde landen van oorsprong voor soorten waarvan aangetoond werd dat ze een bedreiging inhouden voor de inheemse fauna en flora. De bijlagen van de richtlijn 1497/2003 lijsten deze soorten op en worden frequent geactualiseerd.

<span class="plainlinks">
4) De [http://www.vliz.be/imis/imis.php?module=ref&refid=126451 '''Kaderrichtlijn Mariene Strategie'''] of KRMS (Marine Strategy Framework Directive of MSFD, goedgekeurd in 2008) biedt een kader voor de bescherming en het behoud van het marien milieu, het vermijden van schade en het herstel van het milieu in het geval negatieve gevolgen opgetreden zijn. De KRMS heeft als doelstelling de Goede Milieu Toestand (GMT) te bereiken in het marien milieu in 2020 ten laatste. Niet-inheemse soorten worden specifiek behandeld in de bijlage I van deze richtlijn, en de descriptor nr. 2 [http://www.vliz.be/imis/imis.php?module=ref&refid=202485 "Niet-inheemse soorten geïntroduceerd door menselijke activiteiten bevinden zich op een niveau dat niet schadelijk is voor het milieu"] is één van de elf generische kwalitatieve descriptoren die in beschouwing worden genomen voor het bepalen van de GMT. De verdere bepaling van criteria en indicatoren voor het definiëren en opvolgen van doelstellingen staat momenteel ter discussie. De beslissing van de EU Commissie inzake de criteria en methodologische standaarden voor de Goede Milieu Toestand in de Europese mariene wateren ([http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32010D0477%2801%29:EN:HTML COM 2010/477/EU])

Verschillende voorstellen zijn in omloop. In België kiest men voorlopig (augustus 2011) voor het opvolgen van nieuwe introducties van niet-inheemse soorten. Daarbij stelt de bevoegde dienst voor om de indicator voor het behalen van de GMT te omschrijven als 'Geen nieuwe anthropogene introductie van niet-inheemse soorten macrofauna en macroflora (>1mm) (No introduction of human induced non indigenous species of macrofauna and macroflora (l>1mm))

De initiële beoordeling voor niet-inheemse soorten moet in 2012 gerealiseerd zijn, en dient volgende aspecten te omvatten:

- Een analyse van de huidige milieutoestand, inclusief een inventaris van de temporele en ruimtelijke patronen in abundantie van niet-inheemse soorten of – waar relevant – genetisch verschillende vormen van inheemse soorten in (sub)regio’s.

- Een analyse van de dominante drukken en effecten verbonden aan de introductie van niet-inheemse soorten en translocaties.

<span class="plainlinks">
5) [http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32007R0708:EN:NOT '''Richtlijn van de EU Raad (EC) nr 708/2007 met betrekking tot het gebruik van niet-inheemse of lokaal niet-aanwezige soorten in de aquacultuur'''] (uitgevaardigd in 2007) is gericht op het optimaliseren van de voordelen geassocieerd met introducties van niet-inheemse soorten en lokaal niet-aanwezige soorten die gebruikt worden in de aquacultuur.

Er wordt gewaakt over het vermijden van potentieel schadelijke effecten in het ecosysteem en negatieve biologische interacties (incl. genetische uitwisseling met inheemse soorten) en de verdere verspreiding van niet-doelsoorten in natuurlijke habitats. De focus ligt op risico-analyses van niet-inheemse soorten vooraleer een introductie of translocatie toegestaan wordt.

<span class="plainlinks">
6) De '''[http://eur-lex.europa.eu/legal-content/NL/TXT/?qid=1425558355871&uri=CELEX:32014R1143 Verordening (EU) nr. 1143/2014]''' van het Europees Parlement en de Raad van 22 oktober 2014 betreffende de preventie en beheersing van de introductie en verspreiding van invasieve uitheemse soorten is op 1 januari 2015 in werking getreden. De verordening gaat uit van een hiërarchische aanpak op 3 niveaus, zoals ook overeengekomen op internationaal niveau (vb. Biodiversiteitsverdrag), en is van toepassing op terrestrische, aquatische en mariene soorten:
# Preventie
# Vroegtijdige detectie en snelle uitroeiing
# Beheer van de wijdverspreide invasieve soorten
In het kader van deze verordening wordt een Unielijst van prioritaire soorten opgesteld. Eén van de voorwaarden voor het opnemen van uitheemse soorten in deze lijst is dat een gecoördineerde Europees actie verantwoord is en het mogelijk zal maken om de nadelige gevolgen voor de biodiversiteit, de menselijke gezondheid en de economie te voorkomen of te beperken. Deze lijst zal vooral soorten bevatten die nog weinig verspreid zijn op het Europese grondgebied. Een eerste voorstel voor de lijst van voor de Unie zorgwekkende invasieve uitheemse soorten zal uiterlijk op 1 januari 2016 ter goedkeuring worden voorgelegd aan het Comité dat is samengesteld uit experts uit de Lidstaten. Optioneel kunnen ook nationale en regionale lijst opgesteld worden. <br/>
Op nationaal niveau moet een mechanisme voor toezicht, vroegtijdige detectie, uitroeiing of indamming worden ingevoerd om op passende wijze te kunnen optreden met het oog op de detectie van de introductie van deze voor de Unie zorgwekkende uitheemse soorten, de uitroeiing ervan of de beperking van de verspreiding ervan indien ze reeds wijdverspreid zijn op het grondgebied.<br/>
Er wordt tevens een globale juridische verbodsregeling uitgewerkt alsook een afwijkingsmechanisme op de verbodsbepalingen voorzien onder de vorm van vergunningen.
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===Regionale verdragen ===
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1) Het [http://conventions.coe.int/Treaty/en/Treaties/Html/104.htm '''Verdrag inzake Behoud van Europese Wilde Soorten en Habitats of de Bern Conventie'''] (Convention on the Conservation of European Wildlife and Natural Habitats, Bern Convention, afgesloten in 1979, van kracht sinds 1982) is een internationaal juridisch instrument inzake natuurbehoud, met bindende kracht voor de partijen en met als doelstelling het behoud van de wilde fauna en flora soorten en hun natuurlijke habitats in Europa. Verder beoogt de Conventie een goede samenwerking tussen Europese landen tot stand te brengen in dit domein.

Verschillende aanbevelingen uit de Conventie verwijzen naar niet-inheemse soorten. De [https://wcd.coe.int/ViewDoc.jsp?id=1489673&Site=DG4-Nature&BackColorInternet=DBDCF2&BackColorIntranet=FDC864&BackColorLogged=FDC864 aanbeveling Nr. 77] (1999) inzake de uitroeiing van niet-inheemse terrestrische vertebraten is zeer concreet en beveelt tot de uitroeiing van bepaalde soorten die schade veroorzaken in het ecosysteem (zoals bv. de muskusrat (''Ondatra zibethicus'') en de Canadese bever (''Castor canadensis'')). In Artikel 11, par. 2.b van dit Verdrag verbinden de partijen zich tot een strikte naleving van de controle op de introductie van niet-inheemse soorten. [https://wcd.coe.int/ViewDoc.jsp?id=1487287&Site=DG4-Nature&BackColorInternet=DBDCF2&BackColorIntranet=FDC864&BackColorLogged=FDC864 Aanbeveling Nr.57] (1997) verwijst naar de introductie van niet-inheemse organismen in het milieu. [https://wcd.coe.int/ViewDoc.jsp?id=1492507&Site=DG4-Nature&BackColorInternet=DBDCF2&BackColorIntranet=FDC864&BackColorLogged=FDC864 Aanbeveling Nr. 91 (2002)] verwijst naar invasieve, niet-inheemse soorten die een bedreiging vormen voor de biologische diversiteit op eilanden en op zowel geografisch als door evolutie geïsoleerde ecosystemen. [https://wcd.coe.int/ViewDoc.jsp?id=1488695&Site=DG4-Nature&BackColorInternet=DBDCF2&BackColorIntranet=FDC864&BackColorLogged=FDC864 Aanbeveling Nr. 99] (2003) bevat de Europese Strategie inzake Invasieve Niet-inheemse Soorten en spoort de partijen aan om een nationale strategie inzake invasieve niet-inheemse soorten op te stellen en in uitvoering te brengen, rekening houdend met de Europese Strategie inzake Invasieve Niet-inheemse Soorten. Om deze aanbeveling en de Strategie in uitvoering te brengen, wordt samenwerking tussen de partijen en de waarnemende lidstaten van het Verdrag wat betreft de preventie, mitigatie en uitroeiing of beperking van niet-inheemse soorten – daar waar mogelijk en passend - sterk aangemoedigd.

2) Het [http://www.unep-aewa.org/about/introduction.htm '''Akkoord inzake het behoud van Afro-Euroaziatische migrerende soorten watervogels'''] (The Agreement on the Conservation of African-Eurasian Migratory Waterbirds, AEWA, afgesloten in 1995, van kracht sinds 1999) heeft betrekking op 235 vogelsoorten dewelke afhankelijk zijn van wetlands voor minstens een deel van hun jaarlijkse cyclus. Het geografisch gebied van het akkoord omvat 117 landen uit Europa, delen van Azië en Canada, het Midden-Oosten en Afrika.

3) Het [http://www.helcom.fi/Convention/en_GB/text/ '''HELCOM Verdrag'''] (Convention on the Protection of the Marine Environment of the Baltic, HELCOM, afgesloten in 1992, van kracht sinds 2000) is relevant voor de Baltische Zee en richt zich voornamelijk op vervuiling, inclusief biopolutie door schadelijke niet-inheemse soorten. Een [http://www.corpi.ku.lt/nemo/mainnemo.html databank met niet-inheemse soorten voor het Baltische zeegebied] is beschikbaar.

4) Het [http://www.ospar.org/html_documents/ospar/html/OSPAR_Convention_e_updated_text_2007.pdf '''OSPAR Verdrag voor de Bescherming van het Mariene Milieu in de Noordoostelijke Atlantische Oceaan'''] (Convention for the Protection of the Marine Environment of the North-East Atlantic, OSPAR Convention, afgesloten in 1992, van kracht sinds 1998). Dankzij de aangepaste definitie van ‘pollutie’ - vergelijkbaar met de definitie die gehanteerd wordt in het HELCOM Verdrag - is het mogelijk om via het OSPAR Verdrag, de problematiek van niet-inheemse soorten aan te pakken. De definitie verwijst naar "vervuiling" als "''de directe of indirecte introductie door de mens, van grondstoffen of energie in de mariene/maritieme omgeving, dewelke mogelijks schadelijke gevolgen heeft voor de menselijke gezondheid, de levende rijkdommen en mariene ecosystemen, schade aan of interferentie met wettelijk toegestane gebruiksfuncties van de zee''". In de Strategie van de OSPAR Commissie (2010) ter bescherming van het Mariene Milieu van de Noordoostelijke Atlantische Oceaan worden geeft de Commissie aan zich "''in te spannen om de introductie van niet-inheemse soorten door menselijke activiteiten te beperken tot een niveau dat het ecosysteem niet nadelig beïnvloedt''".
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===Richtlijnen en gedragscodes ===
<br><span class="plainlinks">
De [http://www.issg.org/pdf/aliens_newsletters/SupplementIssue11.pdf '''IUCN richtlijnen inzake preventie van het verlies aan Biodiversiteit als gevolg van invasieve niet-inheemse soorten'''] (IUCN Guidelines for the prevention of Biodiversity Loss Caused by Alien Invasive Species, 2000) verwijzen rechtstreeks naar artikel 8 van het Verdrag inzake Biologische Diversiteit (CBD) en hebben als doelstelling de overheden en beheersorganen bij te staan bij de uitvoering van dit artikel, met name om negatieve effecten van invasieve niet-inheemse soorten in te perken. Een expertengroep speciaal toegewijd aan de problematiek van Invasieve soorten (Invasive Species Specialist Group) werkte deze richtlijnen uit.

De [http://intranet.iucn.org/webfiles/doc/SSC/SSCwebsite/Policy_statements/Reintroduction_guidelines.pdf '''IUCN/SSC richtlijnen voor herintroducties'''] (IUCN/SSC guidelines for re-introductions, 1995) zijn een herwerkte versie van de [http://intranet.iucn.org/webfiles/doc/SSC/SSCwebsite/Policy_statements/IUCN_Position_Statement_on_Translocation_of_Living_Organisms.pdf IUCN Positie Paper inzake de Transfer van Levende Organismen in 1987], destijds opgesteld door het Subcomittee SCC inzake de herintroductie zijn gericht op de opzettelijke herintroducties van in gevangenschap gekweekte individuen en maatregelen die nodig zijn om de onopzettelijke introductie van pathogene niet-inheemse soorten te vermijden.

De [http://www.vliz.be/imis/imis.php?module=ref&refid=115831 '''IMO Richtlijnen voor de controle en behandeling van ballastwater teneinde de overdracht van schadelijke organismen te beperken'''] (Resolutie A.868(20) van 1997) bevat vrijblijvende aanbevelingen voor het verminderen en voorkomen van het opnemen en/of spuien van gecontamineerd ballastwater en op het veiligheidsaspect bij het herballasten op zee. Schepen moeten worden geïnformeerd over gebieden waar er zich schadelijk pathogene organismen bevinden of waar afvalwater in zee wordt geloosd om het opnemen van ballastwater in deze gebieden te beperken. Schepen moeten voorkomen ballastwater op te nemen in ondiep water of in gebieden waar de schroeven de bodemsedimenten beroeren. Onnodig ballasten moet worden vermeden. Er zijn drie procedures om het probleem aan te pakken, nl. herballasten op zee, het ballastwater afgeven aan ontvangstinstallaties in de haven of het ballastwater behandelen. De [http://www.imo.org/OurWork/Environment/BallastWaterManagement/Pages/BWMConvention.aspx IMO Ballastwater Conventie] van 2004 (BWM - 13.02.2004) verplicht schepen een 'Ballast Water Management Plan' op te stellen en een 'Ballast Water Record Book' aan boord te hebben waarin alle ballastoperaties worden opgetekend. Een derde element van de Conventie betreft ballastwater uitwisseling ('Ballast Water Exchange') op zee, die bij voorkeur voorbij de 200 zeemijl van het vasteland plaatsvindt. Indien dit niet mogelijk is, moet de uitwisseling van ballastwater in ieder geval verder dan 50 zeemijl uit de kust plaatsvinden en dit in water van minstens 200 meter diep.

De [http://www.ices.dk/reports/general/2003/Codemarineintroductions2003.pdf '''ICES richtlijnen inzake de Introductie en Transfer van Mariene Organismen'''] (ICES code of practice on the Introduction and Transfer of Marine Organisms, 2004) bevatten concrete aanbevelingen voor maatregelen en praktijken om risico's gekoppeld aan de opzettelijke introductie en transfer van mariene organismen te verminderen (zie rapport van de werkgroep). ICES richtte twee werkgroepen op voor het bestuderen van biologische invasies en niet-inheemse soorten: de [http://www.ices.dk/workinggroups/ViewWorkingGroup.aspx?ID=16 ICES/IOC/IMO Working Group on Ballast and Other Ship Vectors] (WGBOSV, zie [http://www.ices.dk/reports/ACOM/2011/WGBOSV/WGBOSV%202011.pdf verslag 2011]) en de [http://www.ices.dk/workinggroups/ViewWorkingGroup.aspx?ID=33 Working Group on Introduction and transfers of Marine Organisms] (WGITMO, zie [http://www.ices.dk/reports/ACOM/2011/WGITMO/WGITMO%202011.pdf verslag 2011]). Daarnaast organiseerde ICES in 2010 een workshop over schadelijk fytoplankton dat mogelijk door middel van ballastwater getransporteerd wordt (zie verslag 2010). In 2005 publiceerde ICES een nieuwe versie van de [http://www.vliz.be/imis/imis.php?module=ref&refid=115829 "Code of Practice"] uit 1995 over de introductie en de transfer van mariene organismen.

De [http://www.peblds.org/ '''Pan-Europese Strategie voor Biologische en LandschapsDiversiteit'''] (Pan-European Biological and Landscape Diversity Strategy, PEBLDS, 1995) biedt een kader voor een gemeenschappelijke benadering van en gezamenlijke doelstellingen voor nationale en regionale actie om het Verdrag inzake Biologische Diversiteit (CBD) in uitvoering te brengen. De strategie is proactief en volgt het voorzorgsbeginsel voor het stoppen van verder verlies aan biodiversiteit. De problematiek van de invasieve niet-inheemse soorten (IAS) werd ter sprake gebracht tijdens de 2de Intergouvernementele Conferentie in Budapest (2002) en de 3de Intergouvernementele Conferentie in Madrid (2003) waar ook een actieplan werd voorgesteld. In Kiev (2010) besloten Ministers en afgevaardigden uit 55 landen tot gezamenlijke doelstellingen om verder verlies van biodiversiteit een halt toe te roepen tegen 2010. De Europese strategie om IAS te bestrijden maakt deel uit van deze doelstellingen.

De [http://www.fao.org/docrep/005/v9878e/v9878e00.HTM '''FAO Code of Conduct for Responsible Fisheries'''] (1995) is een vrijblijvend initiatief dat verwijst naar internationale standaarden en principes met betrekking tot opzettelijke en onopzettelijke introducties gekoppeld aan visserijpraktijken en aquacultuur (zie artikels 9.2.3 en 9.3.1)

Tot slot wordt verwezen naar [http://www.un.org/esa/sustdev/documents/agenda21/english/agenda21toc.htm '''Agenda 21'''] van de VN-conferentie over Milieu en Ontwikkeling (UNCED, 1992), meer bepaald naar [http://www.un.org/esa/sustdev/documents/agenda21/english/agenda21chapter15.htm Hoofdstuk 15] dat het behoud van de biologische diversiteit behandelt. Verschillende hoofdstukken (bv. [http://www.un.org/esa/sustdev/documents/agenda21/english/agenda21chapter17.htm Hoofdstuk 17] (17.30 en 17.79) en [http://www.un.org/esa/sustdev/documents/agenda21/english/agenda21chapter18.htm Hoofdstuk 18] (18.4) en verder van de Agenda 21 verwijzen naar niet-inheemse soorten als één van de bedreigingen in het behalen van de doelstellingen inzake biodiversiteit.
<div style="float:right;font-size:90%">[[Niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria|[Naar intropagina]]]</div>
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[[Category:Niet-inheemse soorten van het Belgisch deel van de Noordzee en aanpalende estuaria ]]

Niet-inheemse soorten Belgisch deel Noordzee en aanpalende estuaria

2021-03-24T12:07:37Z

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{{Box Note|boxtype=warning|Note text=Deze pagina wordt niet langer bijgewerkt. Meer recente info is te vinden op http://www.vliz.be/niet-inheemse-soorten|http://www.vliz.be/niet-inheemse-soorten }}
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<div style="float:right;width:350px; margin:0 4%"> [[Image:Logonietinheemsesoorten.jpg|center|135px|link=Lijst_niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria|naar de lijst]]<br/>
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Deze pagina's tonen een geactualiseerde lijst van de niet-'streek-eigen' mariene en kustgebonden soorten in het Belgische deel van de Noordzee en aanpalende estuaria.
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Via de lijst kun je doorklikken naar fiches met uitgebreide informatie over de levenscyclus en ecologie van de soort, de wijze van introductie en verspreiding, mogelijke effecten of meetbare impact van de soort op het milieu en mogelijke maatregelen. Ook voor taxonomische informatie, foto's en relevante links kun je hier terecht.
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De opmaak en actualisatie van deze lijst is mogelijk gemaakt dankzij de samenwerking met - en de expertise van - wetenschappers, samengebracht in het <span class="plainlinks">[http://www.vliz.be/imis/imis.php?module=project&proid=2170 'VLIZ Alien Species Consortium']</span>.

===Niet-inheemse soorten?===
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Wereldwijd hebben talrijke plant- en diersoorten met veel succes nieuwe leefgebieden gekoloniseerd. Niet-inheemse soorten komen ook voor in het mariene milieu, waarbij ze afkomstig zijn van over heel de wereld. En eenmaal een vreemde soort zich hier heeft gevestigd, is er meestal geen weg terug. <P>

Het probleem van vreemde of niet-inheemse soorten is niet nieuw. In de geschiedenisboeken vinden we meldingen van vroege introducties. Maar voor een aantal soorten is het echter moeilijk te zeggen of ze nu al dan niet inheems zijn. Onze kennis reikt voor sommige groepen zeeorganismen immers niet ver terug in het verleden. Voor de studie van bepaalde vaak kleine organismen zijn onze kennis en onderzoekstechnieken namelijk onvoldoende…<P>

Maar welke invloed hebben deze niet-inheemse soorten op hun omgeving? Hebben ze een effect op de mens of de economie? En hoe kan men de schade, aangebracht door niet-inheemse soorten, beperken?
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===Definities===
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*[[Dwaalgast]]
*[[Niet-inheemse soort]] [[exoot|of exoot]]
*[[Invasieve soort]]
*[[Cryptogene soort]]
*[[Nultijd|Nultijd of ''baseline'']]
*[[Natuurlijke kolonisatie]]
*[[Antropogene introductie]]

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===Studiegebied===
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We geven een overzicht van alle reeds gekende niet-inheemse soorten voor de Belgische kuststrook, het Belgisch deel van de Noordzee, de Oostendse Spuikom en het Schelde-estuarium.

[[Image:Sudiegebied project niet inheemse soorten.jpg|center|680px ]]
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===Lijst van niet-inheemse soorten===
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Hoewel we ernaar streven om een zo volledig mogelijke lijst van niet-inheemse soorten voor te stellen, is dit toch niet evident. Niet-inheemse soorten worden vaak per toeval ontdekt en sommige groepen zijn ook minder goed gekend, zoals bijvoorbeeld het plankton dat bestaat uit microscopisch kleine plantjes en diertjes. Daarbij komt nog dat niet-inheemse soorten soms moeilijk kunnen onderscheiden worden van de lokale soorten, wat kan leiden tot het verkeerdelijk benoemen van een niet-inheemse soort.
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[[Lijst_niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria|Naar de lijst]]
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<u>''Wat vind je terug op deze lijst:''</u> <P>

* alle reeds gekende niet-inheemse soorten die gevestigde populaties hebben in zoute en brakke milieu’s in de Belgische kuststrook, het Belgisch deel van de Noordzee, de Oostendse Spuikom of het Schelde-estuarium.
* als er een vermoeden is dat een cryptogene soort werd geïntroduceerd, werd deze ook aan de lijst toegevoegd
* soorten die – al dan niet opzettelijk – door de mens werden geïntroduceerd.<P>

<u>''Wat vind je NIET op deze lijst:''</u> <P>

* vreemde soorten die langs onze kust werden gesignaleerd, maar waarvan we niet zeker weten of ze zich blijvend hebben gevestigd (= dwaalgasten)
* soorten die enkel in zoetwater voorkomen
* soorten die op een natuurlijke manier hun weg hebben gevonden naar de Belgische kustwateren.
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===Belgische beleidscontext ===
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Naar schatting komen ongeveer 12.000 niet-inheemse soorten voor in Europa, waarvan 10 tot 15% als invasief beschouwd worden. De introductie en de verspreiding van niet-inheemse soorten wordt op supranationaal niveau reeds enige tijd onder de aandacht gebracht in [[Overzichtslijst beleidsinstrumenten#Globale verdragen en akkoorden|globale verdragen en akkoorden]], in [[Overzichtslijst beleidsinstrumenten#Europese richtlijnen en regelgeving|Europese regelgeving]] alsook in [[Overzichtslijst beleidsinstrumenten#Regionale verdragen|regionale verdragen]]. Verder zijn ook een reeks specifieke [[Overzichtslijst beleidsinstrumenten#Richtlijnen en gedragscodes|richtlijnen en gedragscodes]] inzake de aanpak van niet-inheemse soorten beschikbaar. De belangrijkste wetgeving en beleidsinstrumenten die geldig zijn voor de situatie in het studiegebied zijn de Belgische [[Niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria#Wet ter bescherming van het Mariene Milieu |Wet ter bescherming van het Mariene Milieu]] (MMM Wet, 1999), de [[Overzichtslijst_beleidsinstrumenten#Europese_richtlijnen_en_regelgeving|Europese Verordening omtrent invasieve uitheemse soorten]] (Verordening (EG) nr. 1143/2014), de [[Niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria#Europese Kaderrichtlijn Mariene Strategie |Europese Kaderrichtlijn Mariene Strategie ]](KRMS, 2008/56/EG, 2008) en de internationale [[Niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria#IMO Ballastwater Conventie |IMO Ballastwater Conventie]] (2004).
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====''Wet ter bescherming van het Mariene Milieu'' ====
<span class="plainlinks">
In België is het door de [http://www.vliz.be/imis/imis.php?module=ref&refid=115825 Wet ter bescherming van het Mariene Milieu] (Wet Mariene Milieu of MMM Wet, 1999) onder artikel 11 verboden niet-inheemse soorten te introduceren in de zeegebieden onder de rechtsbevoegdheid van Belgie. Opzettelijke en onopzettelijke introducties zijn ook verboden door het Koninklijk Besluit van 21 december 2001 inzake de soortenbescherming in de Belgische zeegebieden. Het Belgisch deel van de Noordzee (BNZ) wordt echter niet systematisch onderzocht op de aanwezigheid van niet-inheemse soorten. Toevallige vondsten en gerichte waarnemingen van niet-inheemse soorten in het BNZ, in de aanpalende estuaria en in de kustgebieden, worden door onderzoekers en door een netwerk van vrijwillige experten gemeld of gepubliceerd. Het [http://www.vliz.be/imis/imis.php?module=project&proid=2170 ‘VLIZ alien species consortium’] verzamelt en beschrijft deze waarnemingen op een systematische manier zodat ze voor eindgebruikers (wetenschappers, beleidsmakers, geïnteresseerd publiek) beschikbaar zijn.</span>
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====''Europese Kaderrichtlijn Mariene Strategie '' ====
<span class="plainlinks">
De EU [http://www.vliz.be/imis/imis.php?module=ref&refid=126451 Kaderrichtlijn Mariene Strategie] (2008/56/EG) (KRMS) biedt een gezamenlijk Europees kader voor de bescherming en het behoud van het mariene milieu in de Europese lidstaten, met aandacht voor het vermijden van schade en het herstel van het milieu in het geval dat negatieve gevolgen opgetreden zijn. De richtlijn werd vertaald in Belgische wetgeving als het KB van 23 juni 2010 betreffende de mariene strategie voor de Belgische Zeegebieden. De KRMS heeft als doelstelling uiterlijk in 2020 de Goede Milieu Toestand (GMT) te bereiken in het mariene milieu. De aanwezigheid en introductie van niet-inheemse soorten worden specifiek behandeld in de bijlage I van deze richtlijn. De descriptor nr. 2 [http://www.vliz.be/imis/imis.php?module=ref&refid=202485 'Niet-inheemse soorten geïntroduceerd door menselijke activiteiten bevinden zich op een niveau dat niet schadelijk is voor het milieu’] is één van de elf generische kwalitatieve descriptoren die in beschouwing worden genomen voor het bepalen van de GMT. De verdere bepaling van criteria en indicatoren voor het definiëren en opvolgen van doelstellingen moet afgerond zijn in 2012, en staat momenteel ook in België nog ter discussie. In België kiest men voorlopig (augustus 2011) voor het opvolgen van nieuwe introducties van niet-inheemse soorten. Daarbij stelt de bevoegde dienst voor om de indicator voor het behalen van de GMT te omschrijven als 'Geen nieuwe antropogene introductie van niet-inheemse soorten macrofauna en macroflora (>1mm)'. Een voorbereidend [http://www.vliz.be/imis/imis.php?module=ref&refid=202485 technisch rapport (2010)] door de Taakgroep van descriptor 2, brengt een aantal van de probleemstellingen voor het bepalen van deze gezamenlijke standaarden aan het licht. Een recent overzicht van beschikbare standaarden en methodes is beschikbaar in een technisch rapport in opdracht van de Europese Commissie (Joint Research Centre, 2011). De Commissie heeft op basis van de eerste wetenschappelijke adviezen, een beslissing gepubliceerd ([http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:32010D0477%2801%29:EN:HTML COM 2010/477/EU]) met verdere inhoudelijke bepalingen van de criteria en de methodologische standaarden in uitvoering van de KRMS en de bepaling van GMT in mariene wateren. De initiële beoordeling voor niet-inheemse soorten moet in 2012 gerealiseerd zijn, en vergt een analyse van de huidige milieutoestand (inclusief een inventaris van de temporele en ruimtelijke patronen in abundantie van niet-inheemse soorten) evenals een analyse van de dominante drukken en effecten verbonden aan de introductie van niet-inheemse soorten en translocaties.</span>
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====''IMO Ballastwater Conventie '' ====
<span class="plainlinks">
Om de introductie van niet-inheemse soorten via de ballasttanken van schepen tegen te gaan, verplicht de [http://www.imo.org/OurWork/Environment/BallastWaterManagement/Pages/BWMConvention.aspxIMO Ballastwater Conventie] (2004) schepen om een ‘Ballast Water and Sediment Management Plan’ op te stellen en een ‘Ballast Water Record Book’ aan boord te hebben waarin alle ballastoperaties worden bijgehouden. Daarnaast dient het beheer van het ballastwater te gebeuren volgens standaardprocedures ([http://www.imo.org/OurWork/Environment/BallastWaterManagement/Pages/BWMGuidelines.aspx zie website IMO]). In afwachting van de ratificatie van deze conventie wordt door de OSPAR Commissie aanbevolen om bepaalde maatregelen met betrekking tot het ballastwater van schepen reeds op een vrijwillige basis na te leven ([http://www.ospar.org/v_measures/get_page.asp?v0=10-07e__Ballast_Water_Guidance.doc&v1=5 OSPAR general guidance 07/2010]). Voorafgaand aan de IMO Ballastwater Conventie gaf de IMO resolutie ([http://www.vliz.be/imis/imis.php?module=ref&refid=115831 A.868(20)]) uit 1997 richtlijnen voor de controle en behandeling van ballastwater teneinde de overdracht van schadelijke organismen te beperken. Andere relevante internationale initiatieven die zich buigen over de rol van de scheepvaart als vector voor de introductie van niet-inheemse soorten zijn de [http://www.ices.dk/indexfla.asp ICES] (International Council for the Exploration of the Sea) werkgroepen voor het bestuderen van biologische invasies en niet-inheemse soorten: de [http://www.ices.dk/workinggroups/ViewWorkingGroup.aspx?ID=16 ICES/IOC/IMO Working Group on Ballast and Other Ship Vectors] (WGBOSV, zie [http://www.ices.dk/reports/ACOM/2011/WGBOSV/WGBOSV%202011.pdf verslag 2011]) en de [http://www.ices.dk/workinggroups/ViewWorkingGroup.aspx?ID=33 Working Group on Introduction and transfers of Marine Organisms] (WGITMO, zie [http://www.ices.dk/reports/ACOM/2011/WGITMO/WGITMO%202011.pdf verslag 2011]). In 2005 publiceerde ICES een nieuwe versie van de [http://www.vliz.be/imis/imis.php?module=ref&refid=115829 ‘Code of Practice’] (goede praktijken) uit 1995 over de introductie en de transfer van mariene organismen.</span>
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====''Ongewenste gasten '' ====
<span class="plainlinks">
Niet-inheemse soorten worden vaak geassocieerd met negatieve effecten voor de lokale biodiversiteit en ecosysteemfuncties. Niet alle exoten hebben een aantoonbare impact op andere soorten of habitats in hun nieuwe milieu. Voor een minderheid is het invasief karakter echter van een dergelijke aard dat ze een probleem stellen voor de lokale biodiversiteitsdoelstellingen, de economie of de volksgezondheid, of de ecosysteemdiensten in het gedrag brengen. Naar schatting vormt ongeveer 10 tot 15% een gevaar voor de Europese biodiversiteit ([http://ec.europa.eu/environment/pubs/pdf/factsheets/Invasive%20Alien%20Species/Invasive_Alien_NL.pdf EU, 2010]). Deze invasieve niet-inheemse soorten (Invasive Alien Species of IAS) worden wereldwijd beschouwd als de tweede belangrijkste oorzaak van het verlies aan biodiversiteit (na de directe vernietiging van habitats) ([http://ec.europa.eu/environment/nature/invasivealien/docs/ias_discussion_paper.pdf EC, 2008]). Het is voor het beleid belangrijk prioritaire aandacht te richten op deze invasieve exoten, en concrete beheersmaatregelen te treffen daar waar dringend en noodzakelijk. Op deze manier kunnen de beheersmaatregelen en de (beperkte) middelen optimaal aangewend worden. Voor België stelde het [http://ias.biodiversity.be/ Belgisch forum over invasieve soorten] een ISEIA-protocol (Invasive Species Environmental Impact Assessment, [http://ias.biodiversity.be/documents/ISEIA_protocol.pdf Branquart (Ed.) 2009]) op. Met dit protocol worden potentieel inwijkende exoten preventief gescreend op basis van een aantal criteria om hun invasieve karakter, hun impact op het leefmilieu of de volksgezondheid, en dus de eventuele noodzaak voor een ‘snelle respons’ te bepalen. De screening aan de hand van dit protocol leidt tot een soortenlijst met verschillende categorieën: een zwarte lijst, een bewakingslijst en een alarmlijst (http://ias.biodiversity.be/). Voor de mariene omgeving werd deze screening voorlopig nog niet uitgevoerd. De best beschikbare informatie met betrekking tot potentiële schadelijke effecten in het mariene milieu van het BNZ, de getijgebonden delen van de IJzer en de Schelde is momenteel samengevat in de soortenfiches die te raadplegen zijn via de [[Lijst_niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria| soortenlijst]] van het [http://www.vliz.be/imis/imis.php?module=project&proid=2170 VLIZ alien species consortium]. Daarnaast is het belangrijk te blijven inzetten op de reeds bestaande algemeen preventieve maatregelen om schadelijke gevolgen van invasieve niet-inheemse soorten te vermijden. Voor het behalen van de Goede Milieu Toestand in 2020, zoals vastgelegd in de KRMS, is een systematische monitoring en gericht onderzoek nodig.</span>
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====''Verordening omtrent invasieve uitheemse soorten'' ====
De [http://eur-lex.europa.eu/legal-content/NL/TXT/?qid=1425558355871&uri=CELEX:32014R1143 Verordening (EU) nr. 1143/2014] van het Europees Parlement en de Raad van 22 oktober 2014 betreffende de preventie en beheersing van de introductie en verspreiding van invasieve uitheemse soorten is op 1 januari 2015 in werking getreden. De verordening gaat uit van een hiërarchische aanpak op 3 niveaus (preventie; vroegtijdige detectie en snelle uitroeiing; beheer van de wijdverspreide invasieve soorten), en is van toepassing op zowel terrestrische, aquatische als mariene soorten. <br/>
In het kader van deze verordening wordt een Unielijst van prioritaire soorten opgesteld. Eén van de voorwaarden voor het opnemen van uitheemse soorten in deze lijst is dat een gecoördineerde Europees actie verantwoord is en het mogelijk zal maken om de nadelige gevolgen voor de biodiversiteit, de menselijke gezondheid en de economie te voorkomen of te beperken. Deze lijst zal vooral soorten bevatten die nog weinig verspreid zijn op het Europese grondgebied. Een eerste voorstel voor de lijst van voor de Unie zorgwekkende invasieve uitheemse soorten zal uiterlijk op 1 januari 2016 ter goedkeuring worden voorgelegd aan het Comité dat is samengesteld uit experts uit de Lidstaten. Optioneel kunnen ook nationale en regionale lijst opgesteld worden.<br/>
Op nationaal niveau moet een mechanisme voor toezicht, vroegtijdige detectie, uitroeiing of indamming worden ingevoerd om op passende wijze te kunnen optreden met het oog op de detectie van de introductie van deze voor de Unie zorgwekkende uitheemse soorten, de uitroeiing ervan of de beperking van de verspreiding ervan indien ze reeds wijdverspreid zijn op het grondgebied.<br/>
Er wordt tevens een globale juridische verbodsregeling uitgewerkt alsook een afwijkingsmechanisme op de verbodsbepalingen voorzien onder de vorm van vergunningen.<br/>
Op nationaal niveau heeft de IAS (''invasive alien species'')-werkgroep in januari 2014 het mandaat gekregen om de juridische, wetenschappelijke en financiële gevolgen van de verordening te analyseren. Deze werkgroep adviseerde de opmaak van een samenwerkingsakkoord in het kader van de bepalingen die gemengde bevoegdheden omvatten, teneinde de juridische en wetenschappelijke coherentie op Belgisch niveau te garanderen. Tevens werd de oprichting van een formeel wetenschappelijk comité op Belgisch niveau geadviseerd, waar de wetenschappelijke expertise in verband met invasieve uitheemse soorten zal worden gecentraliseerd, gecoördineerd en openbaar gemaakt.
<P>
<BR>
<P>

===VLIZ Alien Species Consortium ===
----

Dit project werd gerealiseerd door <span class="plainlinks">[http://www.vliz.be/imis/imis.php?module=project&proid=2170 het Vlaams Instituut voor de Zee (VLIZ) in consortium met andere instituten]</span>.
<P>
<BR>
<P>

[[Category:Niet-inheemse soorten van het Belgisch deel van de Noordzee en aanpalende estuaria ]]

Lijst niet-inheemse soorten Belgisch deel Noordzee en aanpalende estuaria

2021-03-24T12:07:14Z

Admin: Add warning: niet langer bijgewerkt...

{{Box Note|boxtype=warning|Note text=Deze pagina wordt niet langer bijgewerkt. Meer recente info is te vinden op http://www.vliz.be/niet-inheemse-soorten|http://www.vliz.be/niet-inheemse-soorten }}

<span style="color:#00787A; Font-size: 140%">'''Lijst niet-inheemse soorten Belgisch deel Noordzee en aanpalende estuaria''' </span>
----
__NOTITLE__
Deze pagina's tonen een geactualiseerde lijst van de niet-'streek-eigen' mariene en kustgebonden soorten in het Belgische deel van de Noordzee en aanpalende estuaria. [[Niet-inheemse_soorten_Belgisch_deel_Noordzee_en_aanpalende_estuaria|Lees meer...]]

Via de lijst kun je doorklikken naar uitgebreide informatiefiches, inclusief taxonomische informatie, foto's en relevante links. De opmaak en actualisatie van deze lijst is mogelijk gemaakt dankzij de samenwerking met - en de expertise van - wetenschappers, samengebracht in het '<span class="plainlinks">[http://www.vliz.be/imis/imis.php?module=project&proid=2170 VLIZ Alien Species Consortium]</span>'.

<P>
<BR>
<P>

{{lijst
|fotos=
[[Image:Bonamia ostreae.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[Oesterparasiet|oesterparasiet]] <br> Foto: Susan Bower Fisheries and <br> Oceans Canada</div>
[[Image:Antithamnionella_ternifolia.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; line-height:120%; margin:0px 0px 4px 0px">
[[drietakkig rooddonswier]] <br> Foto: Ignacio Bárbara</div>
[[Image:Mnemiopsis ledyi.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[Amerikaanse ribkwal]]<br>Foto: Marco Faasse (<span class="plainlinks">[http://www.acteon.nl/ www.acteon.nl]</span>)</div>
[[Image:Ensis directus.JPG|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[Amerikaanse zwaardschede]]<br> Foto: Karl Van Ginderdeuren</div>
[[Image:Crepidula fornicata.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[muiltje]]<br> Foto: Filip Nuyttens</div>
[[Image:Chelicorophium curvispinum.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[Kaspische slijkgarnaal]]<br> Foto: Lodewijk Roelen </div>
[[Image:Hemigrapsus takanoi2.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[penseelkrab]]<br> Foto: Jonas Mortelmans </div>
[[Image:Elminius_modestus.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[Nieuw-Zeelandse zeepok]]<br> Foto: Vliz (Decleer)</div>
[[Image:Bugula_simplex_2.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[geel vogelkopmosdiertje]] <br> Foto: Hans De Blauwe</div>
[[Image:Botrylloides violaceus.jpg|caption|center|205px|]]
<div style="text-align: center;font-size:80%; margin:0px 0px 4px 0px">
[[gewone slingerzakpijp]] <br> Foto: Hans De Blauwe</div>

|abstract=

<div style="text-align: left;font-size:120%; margin-top:5px;">'''Eéncelligen (1)'''</div>
*[[Oesterparasiet|oesterparasiet - ''Bonamia ostreae'']]

<div style="text-align: left;font-size:120%; margin-top:10px;">'''Algen en wieren (12)'''</div>
*[[drietakkig rooddonswier|drietakkig rooddonswier - ''Antithamnionella ternifolia'']]
*''[[Caulacanthus ustulatus]]''
*[[vertakt viltwier|vertakt viltwier - ''Codium fragile fragile'']]
*''[[Coscinodiscus wailesii]]''
* ''Dasysiphonia japonica''
*''[[Gracilaria vermiculophylla]]''
*[[violet buiswier|violet buiswier - ''Neosiphonia harveyi'']]
*''[[Odontella sinensis]]''
*[[puntig buiswier|puntig buiswier - ''Polysiphonia senticulosa'']]
*[[Japans bessenwier|Japans bessenwier - ''Sargassum muticum'']]
*''[[Thalassiosira punctigera]]''
*[[Japanse kelp|Japanse kelp - ''Undaria pinnatifida'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Vaatplanten (2)'''</div>
*[[struikaster|struikaster - ''Baccharis halimifolia'']]
*[[Engels slijkgras|Engels slijkgras - ''Spartina townsendii var. anglica'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Neteldieren (5)'''</div>
*[[brakwaterpoliep|brakwaterpoliep - ''Cordylophora caspia'']]
*[[groene golfbrekeranemoon|groene golfbrekeranemoon - ''Diadumene lineata'']]
*[[berenvachtpoliep|berenvachtpoliep - ''Garveia franciscana'']]
*[[Amerikaanse ribkwal|Amerikaanse ribkwal - ''Mnemiopsis leidyi'']]
*[[Bache's knotsklokje|Bache's knotsklokje - ''Nemopsis bachei'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Sponzen (1)'''</div>
*[[paarse buisjesspons|paarse buisjesspons - ''Haliclona (Soestella) xena'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Wormen (6)'''</div>
*[[zwemblaasworm|zwemblaasworm - ''Anguillicoloides crassus'']]
* ''Boccardia proboscidea''
* ''Boccardiella hamata''
*[[trompetkalkkokerworm|trompetkalkkokerworm - ''Ficopomatus enigmaticus'']]
*[[Oostzeegroenworm|Oostzeegroenworm - ''Marenzelleria neglecta'']]
*[[langstaartkustworm|langstaartkustworm - ''Tubificoides heterochaetus'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Weekdieren (10)'''</div>

*[[Japanse oester|Japanse oester - ''Crassostrea gigas'']]
*[[muiltje|muiltje - ''Crepidula fornicata'']]
*[[Amerikaanse zwaardschede|Amerikaanse zwaardschede - ''Ensis directus'']]
*[[strandgaper|strandgaper - ''Mya arenaria'']]
*[[brakwatermossel|brakwatermossel - ''Mytilopsis leucophaeata'']]
*[[Amerikaanse boormossel|Amerikaanse boormossel - ''Petricolaria pholadiformis'']]
*[[Jenkins’ waterhoren|Jenkins’ waterhoren - ''Potamopyrgus antipodarum'']]
*[[paalwormen|scheepsworm - ''Psiloteredo megotara'']]
*[[Amerikaanse strandschelp|Amerikaanse strandschelp - ''Rangia cuneata'']]
*[[paalwormen|gewone paalworm - ''Teredo navalis'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Geleedpotigen (31)'''</div>
*[[langsprietroeipootkreeft|langsprietroeipootkreeft - ''Acartia (Acanthacartia) tonsa'']]
* zebrazeespin - ''Ammothea hilgendorfi''
*[[paarsgestreepte zeepok|paarsgestreepte zeepok - ''Amphibalanus amphitrite'']]
*[[brakwaterpok|brakwaterpok - ''Amphibalanus improvisus'']]
* Pacifische zeepok - ''Balanus glandula''
*[[blauwe zwemkrab|blauwe zwemkrab - ''Callinectes sapidus'']]
*[[machospookkreeft|machospookkreeft - ''Caprella mutica'']]
*[[Kaspische slijkgarnaal|Kaspische slijkgarnaal - ''Chelicorophium curvispinum'']]
*[[reuzenvlokreeft|reuzenvlokreeft - ''Dikerogammarus villosus'']]
*[[Nieuw-Zeelandse zeepok|Nieuw-Zeelandse zeepok - ''Elminius modestus'']]
*[[Chinese wolhandkrab|Chinese wolhandkrab - ''Eriocheir sinensis'']]
*[[tijgervlokreeft|tijgervlokreeft - ''Gammarus tigrinus'']]
*[[blaasjeskrab|blaasjeskrab - ''Hemigrapsus sanguineus'']]
*[[penseelkrab|penseelkrab - ''Hemigrapsus takanoi'']]
*[[Kaspische aasgarnaal|bloedrode Kaspische aasgarnaal - ''Hemimysis anomala'']]
*[[estuariene poliepvlo|estuariene poliepvlo - ''Incisocalliope aestuarius'']]
*[[grote roze zeepok|grote roze zeepok - ''Megabalanus coccopoma'']]
*[[zeetulp|zeetulp - ''Megabalanus tintinnabulum'']]
*[[elegante honingvlokreeft|elegante honingvlokreeft - ''Melita nitida'']]
*[[Sexton's slijkgarnaal|Sexton's slijkgarnaal - ''Monocorophium sextonae'']]
*[[rood darmroeipootkreeftje|rood darmroeipootkreeftje - ''Mytilicola intestinalis'']]
* ''Neomysis americana''
*[[oevervlokreeft|oevervlokreeft - ''Orchestia cavimana'']]
*[[rugstreepsteurgarnaal|rugstreepsteurgarnaal - ''Palaemon macrodactylus'']]
*[[zuiders waterezeltje|zuiders waterezeltje - ''Proasellus coxalis'']]
*[[slijkgrascicade|slijkgrascicade - ''Prokelisia marginata'']]
*[[pacifisch eenoogkreeftje |Pacifisch eenoogkreeftje - ''Pseudodiaptomus marinus'']]
*[[Zuiderzeekrabbetje|Zuiderzeekrabbetje - ''Rhithropanopeus harrisii'']]
*[[Stanford’s_naaldkreeftje|Stanford’s naaldkreeftje - ''Sinelobus stanfordi'']]
*[[brede brakwaterpissebed|brede brakwaterpissebed - ''Synidotea laticauda'']]
*[[Japanse dansmug|Japanse dansmug - ''Telmatogeton japonicus'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Mosdiertjes (3)'''</div>
*[[geel vogelkopmosdiertje|geel vogelkopmosdiertje - ''Bugula simplex'']]
*[[vogelkopmosdiertje|vogelkopmosdiertje - ''Bugula stolonifera'']]
*[[onverwacht mosdiertje|onverwacht mosdiertje - ''Tricellaria inopinata'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Zakpijpen (5)'''</div>
*[[glanzende bolzakpijp|glanzende bolzakpijp - ''Aplidium glabrum'']]
*[[gewone slingerzakpijp|gewone slingerzakpijp - ''Botrylloides violaceus'']]
*[[grijze korstzakpijp |geleikorstzakpijp - ''Diplosoma listerianum'']]
*[[ronde zakpijp|ronde zakpijp - ''Molgula manhattensis'']]
*[[knotszakpijp|knotszakpijp - ''Styela clava'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Raderdieren (1)'''</div>
*[[tropisch puzzelraderdier|tropisch puzzelraderdier - ''Keratella tropica'']]

<div style="text-align: left;font-size:120%; margin-top:10px">'''Vissen (2)'''</div>
*[[knorrepos|knorrepos - ''Micropogonias undulatus'']]
*zwartbekgrondel - ''Neogobius melanostomus''
}}

[[Category:Niet-inheemse soorten van het Belgisch deel van de Noordzee en aanpalende estuaria ]]

Template:Kader4

2021-03-24T12:05:50Z

Admin: Add warning: niet langer bijgewerkt...

{{Box Note|boxtype=warning|Note text=Deze pagina wordt niet langer bijgewerkt. Meer recente info is te vinden op http://www.vliz.be/niet-inheemse-soorten|http://www.vliz.be/niet-inheemse-soorten }}

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Template:Box Note/styles.css

2021-03-24T11:59:43Z

Admin: Admin changed the content model of the page Template:Box Note/styles.css from "wikitext" to "Sanitized CSS": This is proper CSS

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Template:Box Note/styles.css

2021-03-24T11:49:08Z

Admin: retry

Template:Box Note

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Admin: add styling

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Admin: add noinclude

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Template:Box Note

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Admin: Taken from https://en.wiki.bluespice.com/wiki/Manual:Template/Example/Notification_Box

Portal:Contents/Portals

2021-01-22T23:47:28Z

Admin: update gifs link

==Portals==

Project-specific portals are part of the Coastal and Marine Wiki. At the moment the following portals are available:
{| class="plainlinks"
|valign="top"|[[Image:encora_port.jpg|200px|thumb|link=ENCORA_portal|[[ENCORA_portal|Portal on SoA European Coastal Research (ENCORA)]]]]
|valign="top"|[[Image:marbef_port.jpg|thumb|200px|link=http://www.marbef.org/wiki/Portal:Marine_Biodiversity|[http://www.marbef.org/wiki/Portal:Marine_Biodiversity Portal on Marine Biodiversity (MarBEF NoE)]]]
|valign="top"|[[Image:Portal euromarine.png|thumb|200px|link=http://www.coastalwiki.org/wiki/Portal:Euromarine|[http://www.coastalwiki.org/wiki/Portal:Euromarine Portal with information from three marine FP6 networks]]]
|-
|valign="top"|[[Image:spicosa_port.jpg|200px|link=http://www.coastalwiki.org/spicosa/Portal:SPICOSA|thumb|[http://www.coastalwiki.org/spicosa/Portal:SPICOSA Portal on Science - Policy Integration for Coastal System Assessment (SPICOSA)]]]
|valign="top"|[[Image:tox_port.jpg|thumb|link=Portal:Ecotox|200px|right|[[Portal:Ecotox|Portal on Marine Ecotoxicology]]]]
|valign="top"|[[Image:Portal_marine_biotech.jpg|link=http://www.marinebiotech.eu/wiki/|thumb|200px|[http://www.marinebiotech.eu/wiki/ Portal on Marine Biotechnology]]]
|-
|valign="top"|[[Image:theseus_port.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:THESEUS|200px|[http://www.coastalwiki.org/wiki/Portal:THESEUS Portal on Innovative technologies for safer European coasts in a changing climate (THESEUS)]]]
|valign="top"|[[Image:Pegaso.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:PEGASO|200px|[http://www.coastalwiki.org/wiki/Portal:PEGASO Portal on People for Ecosystem Based Governance in Assessing Sustainable Development of Ocean and Coast (PEGASO)]]]
|valign="top"|[[Image:Mermaid.jpg|thumb|link=http://www.coastalwiki.org/wiki/Portal:MERMAID|200px|[http://www.coastalwiki.org/wiki/Portal:MERMAID Innovative Multi-purpose offshore platforms: planning, design and operation (MERMAID)]]]
|-
|valign="top"|[[Image:GIFS_portal.png|thumb|link=http://www.coastalwiki.org/wiki/Portal:GIFS|200px|[http://www.coastalwiki.org/wiki/Portal:GIFS Portal on the Geography of inshore Fishing and Sustainability (GIFS)]]]
|valign="top"|[[Image:Portal_eutrophication.png|thumb|link=Portal:Eutrophication|200px|[[Portal:Eutrophication|Portal on Eutrophication]] ]]
|
|}

Template:Concept

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<includeonly>
__NOTITLE__<h1 id="firstHeading">{{{label}}}</h1>
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Template:Concept

2020-11-09T21:14:56Z

Admin: Make sure URI resolve (although not strictly needed)

Some definitions of Integrated Coastal Zone Management (ICZM)

2020-09-14T08:57:36Z

Admin: add link to Vallega (2002)

These definitions are from Vallega, A. 2002, Coastal Management: the Integration Principle.
<ref> Vallega, A. 2002, Coastal Management: the Integration Principle https://books.google.com/books?hl=en&id=R2OGAgAAQBAJ</ref>

== Inter-governmental organisations ==

''"The overall objective of an integrated management programme, like [[Integrated Coastal Zone Management (ICZM)|ICZM]], is to provide for the best long-term and sustainable use of coastal natural resources and for perpetual mantenance of the most natural environment"''

FAO, Clark 1992

''"The most appropriate process to address current and long-term coastal management issues, including habitat loss, degradation of water quality, changes in hydrological cycles, depletion of coastal resources, and adaptation to sea level rise and other impacts of global climate change"''

Intergovernmental Panel on Climate Change 1994

''"An adaptative process of resource management for environmentally sustainable development in coastal areas. It is not a substitute for sectoral planning, but focuses on the linkages between sectoral activities to achieve more comprehensive goals"''

UNEP 1995

''"ICZM is a strategy for an integrated approach to planning and management, in which all policies, sectors and, to the highest possible extent, individual instests are properly taken into account, with the proper consideration given to the full range of temporal and spatial scales, and involving stakeholders in a participative way. It demands good communication among governing authorities (local, regional and national), and promises to address all three dimensions of sustainability: socio/cultural, economic and environmental. It thus provides management instruments that are not per se included or foreseen in the different policies and directives in such comprehensiveness."''

Rupprecht Consult & International Ocean Institute 2006

== Science ==

''"A dynamic process in which a coordinated strategy is developed and implemented for the allocation of environmental, socio-cultural, and institutional resources to achieve the conservation and sustainable multiple use of the coastal zone"''

Coastal Area Management and Planning Network 1989

''"...to allow multi-sectoral development to progress with the fewest unintended setbacks and the least possible imposition of long-run social costs"''

Scura, Chua, Pido and Paw 1992

''"A continuous and dynamic process that recognises the distinctive character of the coastal zone -itself a valuable resource- for current and future generations"''

Cicin-Sain 1993

''"The integration of environmental protection goals into economic and technical decision-making process"''

Kenchington and Crawford 1993

''"A holistic approach, in which the ecosystem as a whole (all the biotic and abiotic components) and all kinds of coastal use, as well as all use -use and use- ecosystem relationships are included"''

Vallega 1993

''"The integrated planning and management of coastal resources and environments in a manner that is based on the physical socio-economic, and political interconnections both within and among the dynamic coastal systems, which when aggregated together, define a coastal zone"''

Sorensen 1997

''"Integrated coastal management is a process that recognises the distinctive character of the coastal area -itself a valuable resources- and the importance of conserving it for current and future generations"''

Cicin-Sain and Knecht 1998

''"ICZM aims to preserve coastal resources, their ecological functioning and ultimately their values by applying adequate land use planning within a social, institutional and economic context"''

Skourtos et al 2005

==References==
<references/>

[[Category:Integrated coastal zone management]]

MediaWiki:Common.css

2020-05-11T21:02:53Z

Admin: "mrow span" 14px for formulas

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color: #FFFFFF;
cursor: pointer;
display: inline-block;
font-size: 16px;
font-weight: lighter;
line-height: 20px;
margin: 5px 0 0;
padding: 5px 15px;
vertical-align: bottom;
text-decoration:none;
}

.button a
{
color: #FFFFFF;
cursor: pointer;
font-size: 16px;
font-weight: lighter;
line-height: 20px;
vertical-align: bottom;
text-decoration:none;
}

a.smallbutton, .smallbutton{
cursor: pointer;
font-size: 9px;
font-weight: lighter;
line-height: 10px;
padding: 0 5px;
background: none repeat scroll 0 0 #0d556f;
border: 0 none;
border-radius: 3px;
text-decoration:none;
color:white;
text-decoration:none;
box-shadow: 1px 1px 1px 1px #777;
}

.smallbutton a,.collapseButton a
{
cursor: pointer;
font-size: 9px;
font-weight: lighter;
line-height: 10px;
text-decoration:none;
color:white;
text-decoration:none;
}

a.mediumbutton, .mediumbutton, .mediumbutton:visited, .mediumbutton a:visited, .mediumbutton:visited,.collapseButton a,.collapseButton a:visited {
cursor: pointer;
font-size: 12px;
font-weight: lighter;
line-height: 13px;
padding: 0 8px;
background: none repeat scroll 0 0 #0d556f;
border: 0 none;
border-radius: 3px;
text-decoration:none;
color:white;
text-decoration:none;
box-shadow: 1px 1px 1px 1px #777;
}

.mediumbutton a,.collapseButton a{
cursor: pointer;
font-size: 12px;
font-weight: lighter;
line-height: 13px;
text-decoration:none;
color:white !important;
}

a.smallbutton:hover,.smallbutton:hover, a.mediumbutton:hover,.mediumbutton:hover, a.button:hover,.button:hover,.collapseButton a:hover
{
background-color: #11BBF3;
}

/*daphnis 20140924 for traits wiki*/
.hidetitlesemantictree p{
visibility: hidden;
}
.hidetitlesemantictree p b{
visibility:visible;
}
.hidetitlesemantictree p strong{
visibility:hidden;
}

.hidetitlesemantictree p
{
margin:0px;
line-height:6px;
}

/*daphnis 20141008 hide eye in properties*/
td.smwpropname span.smwbrowse {
display:none;
}
td.smwpropname {vertical-align: middle!important}

.hidethis {
display:none;
}

/*photogallery 20140926*/
.photogallery_table_img_caption, .hidethis {
white-space: pre-line;
}

.fullImageLink img, #file img{
max-width: 100%;
}

.collapseButton {
float: right;
}

/*Gifs portal 20141105*/
.gifs-map {
background-color:#3a75c4;
text-align:center;
padding:0;
margin:0;
font-family: Helvetica!important;
font-size: 11px!important;
text-decoration:none!important;
width:670px
}

.gifs-map a {
color: white !important;
font-weight: bold
}
.gifs-map-active a {
color: #003893 !important;
}

#gifs-mapupper {
text-transform: uppercase;
}

/*Help semantic maps table*/
.basictable{
background-color: #f9f9f9;
border: 1px solid #aaa;
border-collapse: collapse;
color: black;
margin: 1em 0 ;
}
.basictable td, .basictable th {
border: 1px solid #aaa;
padding: 2px;
}

.basictable th {
background-color: #21409A;
color: white
}

/*daphnis 2016-08-19 historic table*/

.Histobelzee {float: right; margin: 1em; width:40%}
.Histobelzee td {padding: 2px; font-size:85%; line-height: 130%}
.Histobelzee th {background-color: #006784; font-size:90%; text-align: left}

.mrow span {
font-size: 14px;
}