Beach scraping
Definition of Beach scraping:
The process of mechanically removing a layer of sand from the foreshore and transferring it to the backshore[1].
This is the common definition for Beach scraping, other definitions can be discussed in the article
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Practice
Beach scraping is essentially different from beach nourishment. Nourishment involves sand being imported from outside the active coastal zone, whereas with beach scraping, sand is redistributed within the active coastal system. When the scraped sand is placed in the dune or applied to the dune foot, it contributes to reinforcing the dune protection function.
Beach scraping can be viewed as mimicking the natural recovery of the beach profile after storm erosion. Besides, by lowering the foreshore, beach scraping can also promote natural beach recovery processes. However, excessive scraping may cause oversteepening of the beach profile and additional erosion in subsequent storms[2]. The beach profile after scraping should remain in the range of naturally occurring beach profiles.
Ecological impact
The ecological impacts of incidental beach scraping are generally minor. The high-energy intertidal zone hosts organisms adapted to frequent disturbance and capable to recover swiftly[2]. However, removal of beach wrack on a regular basis affects wrack-derived ecological processes and food-web structure on sandy beaches[3]. Significant differences in community structure, including depressed species richness, abundance, and biomass of macrofauna, especially for wrack-associated taxa, were found to be associated with wrack removal on Californian beaches, also reducing the prey available to vertebrate predators, such as shorebirds[4]. Other precautions include avoiding removal of sand-trapping and sand-binding beach vegetation and timing of beach scraping interventions outside periods of turtle nesting.
Beach ploughing
Beach ploughing consists of mechanically ploughing the intertidal area of a beach to create ridges and furrows. This beach state enhances wave energy dissipation and therefore generates more accretive conditions through wave-induced sand transport over the ridges and furrows. Accelerated natural onshore bar migration after beach ploughing is observed in laboratory experiments and in the field[5]. Natural smoothing of the artificially created relief occurs on the timescale of hours. Frequent ploughing is therefore necessary to produce a substantial lasting effect.
References
- ↑ Clark, R. 2005. Hurricane Dennis Supplemental Damage Assessment Report: Impact of Hurricane Dennis on Dog Island and Discussion of Post-Storm Recovery Responses. Florida Department of Environmental Protection, Division of Water Resource Management, Bureau of Beaches and Coastal Systems
- ↑ 2.0 2.1 Carley, J.T., Shand, T.D., Coghlan, I.R., Blacka, M.J., Cox, J., Littman, A., Fitzgibbon, B., Mclean, G. and Watson, P. 2010. Beach scraping as a coastal management option. 19th NSW Coast. Conf. (2010), pp. 1-20
- ↑ Vieira, J.V., Ruiz-Delgado, M.C., Reyes-Martínez, M.J., Borzone, C.A., Asenjo, A., Sanchez-Moyano, J.E. and García-García, F.J. 2016. Assessment the short-term effects of wrack removal on supralittoral arthropods using the M-BACI design on Atlantic sandy beaches of Brazil and Spain. Mar. Environ. Res., 119: 222-237
- ↑ Dugan, J.E., Hubbard, D.M., McCrary, M.D. and Pierson, M.O. 2003. The response of macrofauna communities and shorebirds to macrophyte wrack subsidies on exposed sandy beaches of southern California. Estuar. Coast Shelf Sci., 58: 25-40
- ↑ Pellon, A., Aniel-Quiroga, I., Gonzalez, M. Medina, R. and Vidal, C. 2023. Working with nature to enhance beach accretion: Laboratory experiments of beach ploughing. Coastal Engineering 180, 104267
