https://www.coastalwiki.org/w/index.php?title=Sand_spit&feed=atom&action=historySand spit - Revision history2024-03-29T13:49:00ZRevision history for this page on the wikiMediaWiki 1.31.7https://www.coastalwiki.org/w/index.php?title=Sand_spit&diff=80205&oldid=prevDronkers J at 14:25, 9 May 20232023-05-09T14:25:35Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>A sand spit develops as a result of littoral drift <math>Q_l</math> (= longshore sediment transport) at a location <math>x_s</math> where the shoreline bends away from the incident waves (Fig. 2). Littoral drift is generated by breaking of obliquely incident waves and follows the direction of the longshore component of the incident waves. In situations with small-moderate incident wave angles,  the littoral drift increases at the updrift side until reaching a maximum at <math>x_s</math> on the bending shoreline, while at the downdrift side the littoral driff decreases, as explained below. Sediment will thus accumulate downdrift of the location <math>x_s</math>, initiating the development of a sand spit.   </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>A sand spit develops as a result of littoral drift <math>Q_l</math> (= longshore sediment transport) at a location <math>x_s</math> where the shoreline bends away from the incident waves (Fig. 2). Littoral drift is generated by breaking of obliquely incident waves and follows the direction of the longshore component of the incident waves. In situations with small-moderate incident wave angles,  the littoral drift increases at the updrift side until reaching a maximum at <math>x_s</math> on the bending shoreline, while at the downdrift side the littoral driff decreases, as explained below. Sediment will thus accumulate downdrift of the location <math>x_s</math>, initiating the development of a sand spit.   </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Littoral drift depends on the incident flux of wave energy and on the angle <math>\alpha</math> of the incident waves with the shore-normal direction (Fig. 2). If this angle is small, the longshore transport increases with increasing <math>\alpha</math> approximately as <math>\sin \alpha</math>. However, the amount of wave energy received per unit shoreline length decreases approximately as <math>\cos \alpha</math>. The longshore transport is thus approximately proportional to <math>\cos \alpha \sin \alpha = ½ \sin 2 \alpha</math>. Downdrift of the location <math>x_s</math> where the wave incidence angles become around 45<sup>o</sup> or larger, the longshore sediment transport thus decreases, implying sand accumulation in this zone.   </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Littoral drift depends on the incident flux of wave energy and on the angle <math>\alpha</math> of the incident waves with the shore-normal direction (Fig. 2). If this angle is small, the longshore transport increases with increasing <math>\alpha</math> approximately as <math>\sin \alpha</math>. However, the amount of wave energy received per unit shoreline length decreases approximately as <math>\cos \alpha</math> <ins class="diffchange diffchange-inline">(the distance along the coast between parallel wave rays with incident angle <math>\alpha</math> is proportional to <math>1/\cos \alpha</math>)</ins>. The longshore transport is thus approximately proportional to <math>\cos \alpha \sin \alpha = ½ \sin 2 \alpha</math> <ins class="diffchange diffchange-inline">(see [[Littoral drift and shoreline modelling#Appendix: Derivation of Eq. (2)|explanation]])</ins>. Downdrift of the location <math>x_s</math> where the wave incidence angles become around 45<sup>o</sup> or larger, the longshore sediment transport thus decreases, implying sand accumulation in this zone.   </div></td></tr>
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</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Sand_spit&diff=79742&oldid=prevDronkers J at 09:54, 24 June 20222022-06-24T09:54:24Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Many back-barrier lagoons with highly variable river inflow experience seasonal closure of the sea outlet by spit growth in summer periods when the streamflow is low, long-period</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Many back-barrier lagoons with highly variable river inflow experience seasonal closure of the sea outlet by spit growth in summer periods when the streamflow is low, long-period</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>swell waves dominate and longshore transport rates are high<ref>Ranasinghe, R. and Pattiaratchi, C. 2003. The seasonal closure of tidal inlets. Coastal Engineering Journal 45: 601-627</ref>. The <del class="diffchange diffchange-inline">spit can </del>be breached <del class="diffchange diffchange-inline">during severe storm events, but breaching occurs more usually </del>at high river discharge. <del class="diffchange diffchange-inline">In the latter case the </del>coastal zone around the lagoon can be flooded before the outlet is fully restored.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>swell waves dominate and longshore transport rates are high<ref>Ranasinghe, R. and Pattiaratchi, C. 2003. The seasonal closure of tidal inlets. Coastal Engineering Journal 45: 601-627</ref>. The <ins class="diffchange diffchange-inline">barrier will </ins>be breached at high river discharge. <ins class="diffchange diffchange-inline">The </ins>coastal zone around the lagoon can be flooded before the outlet is fully restored<ins class="diffchange diffchange-inline">. Lagoon barriers can also be breached during severe storm surges (hurricanes, typhoons) due to erosion by overwashing waves and flow; this will become more </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">common as a result of sea-level rise<ref>Nienhuis, J.H., Heijkers, L.G.H. and Ruessink, G. 2021. Barrier breaching versus overwash deposition: Predicting the morphologic impact of storms on coastal barriers. Journal of Geophysical Research: Earth Surface, 126, e2021JF006066</ref></ins>.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Spit development depends crucially on the updrift sand supply. If the updrift sand supply is interrupted or if the sand supply during a long period is smaller than the along-spit sand transport capacity, the spit will breach at an updrift location while the distal end continues to grow<ref>Ollerhead, J. and Davidson-Arnott, R.G.D. 1995. The evolution of Buctouch spit, New Brunswick, Canada. Mar. Geol. 124: 215–236</ref>. Model experiments suggest that the width of a spit does not only depend on the longshore sand transport, but also on the width of the surf zone<ref name=P8/>.   </div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>Spit development depends crucially on the updrift sand supply. If the updrift sand supply is interrupted or if the sand supply during a long period is smaller than the along-spit sand transport capacity, the spit will breach at an updrift location while the distal end continues to grow<ref>Ollerhead, J. and Davidson-Arnott, R.G.D. 1995. The evolution of Buctouch spit, New Brunswick, Canada. Mar. Geol. 124: 215–236</ref>. Model experiments suggest that the width of a spit does not only depend on the longshore sand transport, but also on the width of the surf zone<ref name=P8/>.   </div></td></tr>
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</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Sand_spit&diff=79732&oldid=prevDronkers J at 14:46, 22 June 20222022-06-22T14:46:26Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Definition|title= Sand spit</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>{{Definition|title= Sand spit</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Description==</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[File:SandSpitsSenegalRiverNov2020.jpg|thumb|300px|<del class="diffchange diffchange-inline">left</del>|Sand spits at the mouth of the Senegal river. The turbid Senegal river plume is clearly visible. The spit at the upper part of the image is the tip of the "Langue de Barbarie". The orientation of the wave crests indicates oblique wave incidence from the north, implying north-to-south littoral drift. <del class="diffchange diffchange-inline">Other </del>notable features are: an ebb shield at the river mouth; an ebb [[Deltas|delta]] at the southern inlet <del class="diffchange diffchange-inline">; so-called "flying spits" around the river mouth</del>; cuspate [[rhythmic shoreline features]] on the landward side of the spit. Google Earth image.]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[File:SandSpitsSenegalRiverNov2020.jpg|thumb|300px|<ins class="diffchange diffchange-inline">right</ins>|<ins class="diffchange diffchange-inline"><small>Fig. 1. </ins>Sand spits at the mouth of the Senegal river. The turbid Senegal river plume is clearly visible. The spit at the upper part of the image is the tip of the "Langue de Barbarie". The orientation of the wave crests indicates oblique wave incidence from the north, implying north-to-south littoral drift. <ins class="diffchange diffchange-inline">South of the Langue de Barbarie a so-called flying spit has developed; other smaller flying spits are also visible. Further </ins>notable features are: an ebb shield at the river mouth; an ebb [[Deltas|delta]] at the southern inlet ; cuspate [[rhythmic shoreline features]] on the landward side of the spit. Google Earth image.<ins class="diffchange diffchange-inline"></small></ins>]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Sand spits are an ubiquitous feature of sandy coasts with prevailing oblique wave incidence and associated strong littoral drift. Sand spits usually develop where the coastline bends away from the incident waves. The spit follows the longshore direction of the updrift coast. The tip of the spit is typically curved in onshore direction, due to phenomena such as<ref>Zenkovich, V.P. 1967. Processes of coastal development. Oliver & Boyd, London. 738 pp.</ref><ref>Dan, S., Walstra, D.J.R., Stive, M.J.F. and Panin, N. 2011. Processes controlling the development of a river mouth spit. Marine Geology 280: 116–129</ref><ref>Qi, Y., Yu, Q., Gao, S., Li, Z., Fang, X. and Guo, Y. 2021. Morphological evolution of river mouth spits: Wave effects and self-organization patterns. Estuarine, Coastal and Shelf Science 262, 107567</ref>: </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* wave-induced cross-shore sediment transport; </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* overwash: sand washed over the spit by overtopping waves and deposited at the leeside; </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* incidental changes in the wave incidence direction;</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* wave refraction at the distal end of the spit. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Onshore bending of the tip of a sandspit triggers the development of a new protrusion at the distal end<ref name=P8>Petersen, D., Deigaard, R., Fredsøe, J. 2008. Modelling the morphology of sandy spits. Coastal Engineering 55: 671–684</ref>; this leads to the often observed finger-shaped spit form. </ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">==Notes==</del></div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Sand spits can block the river outflow, causing the river mouth to migrate in downdrift direction. A <ins class="diffchange diffchange-inline">typical </ins>example is the "Langue de Barbarie", a sand spit that forces the mouth of the Senegal river several tens of kilometers to the south (<ins class="diffchange diffchange-inline">Fig. 1</ins>). The spit is breached incidentally in situations of exceptional river discharge. After every breach, the <ins class="diffchange diffchange-inline">sand </ins>spit resumes its southward growth of several hundred meters per year<ins class="diffchange diffchange-inline"><ref>Barusseau, J.P., Ba, M., Descamps, C., Diop, E.H.S., Giresse, P. and Saos, J.L. 1995. Coastal evolution in Senegal and Mauritania at 103, 102 and 101-year scales: natural and human records. Quaternary International 29/30: 61-73</ref></ins>.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">Sand spits are ubiquitous on sandy coasts with strong littoral drift; they usually develop where the coastline bends inland from the longshore drift direction. The spit follows the longshore direction of the updrift coast. The tip of the spit is typically curved in onshore direction, due to phenomena such as: </del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">*overwash: sand washed over the spit by overtopping waves and deposited at the leeside; </del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">* incidental changes in the wave incidence direction; </del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">*  flood currents around the tip of the spit.</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Sand spits can block the river outflow, causing the river mouth to migrate in downdrift direction. A <del class="diffchange diffchange-inline">famous </del>example is the "Langue de Barbarie", a sand spit that forces the mouth of the Senegal river several tens of kilometers to the south (<del class="diffchange diffchange-inline">see the figure</del>). The spit is breached incidentally in situations of exceptional river discharge. After every breach, the spit resumes its southward growth of several hundred meters per year.  </div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Many back-barrier lagoons with highly variable river inflow experience seasonal closure of the sea outlet by spit growth in summer periods when the streamflow is low, long-period</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">swell waves dominate and longshore transport rates are high<ref>Ranasinghe, R. and Pattiaratchi, C. 2003. The seasonal closure of tidal inlets. Coastal Engineering Journal 45: 601-627</ref>. The spit can be breached during severe storm events, but breaching occurs more usually at high river discharge. In the latter case the coastal zone around the lagoon can be flooded before the outlet is fully restored.</ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">Many back barrier lagoons with highly variable river inflow experience seasonal closure of </del>the <del class="diffchange diffchange-inline">sea outlet by growth of </del>the spit <del class="diffchange diffchange-inline">in periods </del>of <del class="diffchange diffchange-inline">drought</del>. <del class="diffchange diffchange-inline">The </del>spit <del class="diffchange diffchange-inline">is breached at high river discharge</del>, but the <del class="diffchange diffchange-inline">coastal </del>zone <del class="diffchange diffchange-inline">around the lagoon may be flooded before the outlet is fully restored</del>.</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">Spit development depends crucially on the updrift sand supply. If the updrift sand supply is interrupted or if the sand supply during a long period is smaller than </ins>the <ins class="diffchange diffchange-inline">along-spit sand transport capacity, </ins>the spit <ins class="diffchange diffchange-inline">will breach at an updrift location while the distal end continues to grow<ref>Ollerhead, J. and Davidson-Arnott, R.G.D. 1995. The evolution </ins>of <ins class="diffchange diffchange-inline">Buctouch spit, New Brunswick, Canada</ins>. <ins class="diffchange diffchange-inline">Mar. Geol. 124: 215–236</ref>. Model experiments suggest that the width of a </ins>spit <ins class="diffchange diffchange-inline">does not only depend on the longshore sand transport</ins>, but <ins class="diffchange diffchange-inline">also on </ins>the <ins class="diffchange diffchange-inline">width of the surf </ins>zone<ins class="diffchange diffchange-inline"><ref name=P8/></ins>. <ins class="diffchange diffchange-inline"> </ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br clear=all></div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br clear=all></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">==Explanation==</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">[[File:SandSpitDevelopment.jpg|thumb|400px|left|<small>Fig. 2. Spit development on a bending shoreline under small-moderate wave incidence angle <math>\alpha</math>. Blue dashed lines = wave rays. Red arrows = sand transport rate. Downdrift from <math>x_1</math> the wave incidence angle <math>\alpha</math> increases; the sand transport rate increases alike till reaching a maximum at <math>x_s</math>, where approximately <math>\alpha=</math>45<sup>o</sup>. Downdrift from <math>x_s</math> the wave angle <math>\alpha</math> increases further, but this increase is now associated with a decrease of the sand transport rate. The resulting sand accumulation downdrift of <math>x_s</math> initiates the development of a sand spit (hatched in the figure).</small>]]  </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">A sand spit develops as a result of littoral drift <math>Q_l</math> (= longshore sediment transport) at a location <math>x_s</math> where the shoreline bends away from the incident waves (Fig. 2). Littoral drift is generated by breaking of obliquely incident waves and follows the direction of the longshore component of the incident waves. In situations with small-moderate incident wave angles,  the littoral drift increases at the updrift side until reaching a maximum at <math>x_s</math> on the bending shoreline, while at the downdrift side the littoral driff decreases, as explained below. Sediment will thus accumulate downdrift of the location <math>x_s</math>, initiating the development of a sand spit.  </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Littoral drift depends on the incident flux of wave energy and on the angle <math>\alpha</math> of the incident waves with the shore-normal direction (Fig. 2). If this angle is small, the longshore transport increases with increasing <math>\alpha</math> approximately as <math>\sin \alpha</math>. However, the amount of wave energy received per unit shoreline length decreases approximately as <math>\cos \alpha</math>. The longshore transport is thus approximately proportional to <math>\cos \alpha \sin \alpha = ½ \sin 2 \alpha</math>. Downdrift of the location <math>x_s</math> where the wave incidence angles become around 45<sup>o</sup> or larger, the longshore sediment transport thus decreases, implying sand accumulation in this zone.  </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"><br clear=all></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">[[File:DamiettaSpit.jpg|thumb|400px|right|<small>Fig. 3. Sand spit at the east promontory of the Damietta Nile outlet. The Nile delta is subject to oblique waves from the NW sector, producing a strong west-east littoral drift. The Damietta sand spit was originally fed with sand from the Nile and later, after construction of the Aswan High Dam, with sediment eroded from the east Damietta promontory. The sand spit is currently sediment starved, after the protection of the promontory with a hard seawall. The sand spit is thinning and moving southward, causing erosion of the shoreline to the south. Overwash processes and wave diffraction around the tip are bending the distal end towards the shore.</small>]]  </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">The initial sand spit development increases locally the curvature of the shoreline. Sand spit development is therefore a continuing, self-reinforcing process (an instability). Very long sand spits may arise in this way. However, in practice they have a finite length, depending on the processes that counteract sand spit growth beyond a certain limit. These processes are:</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* Cross-shore sediment transport and overwash processes, that bend the sand spit towards the shoreline (Fig. 3).</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">* Cross-shore currents at river mouths and tidal inlets, that erode the sand spit extremity (Fig. 1).</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"><br clear=all></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">[[File:FlyingSpitGrowth.jpg|thumb|400px|left|<small>Fig. 4. Flying spit development on a straight shoreline under highly oblique wave incidence <math>\alpha ></math>45<sup>o</sup>. Blue dashed lines = wave rays. Red arrows = sand transport rate. The shoreline is initially disturbed with a small bulge between <math>x_1</math> and <math>x_2</math>. Downdrift from <math>x_1</math>, the wave incidence angle <math>\alpha</math> first decreases and then increases on the updrift side of the bulge. The sand transport rate increases alike till reaching a maximum at <math>x_s</math>, where approximately <math>\alpha \approx</math>45<sup>o</sup>. Downdrift from <math>x_s</math>, the wave angle <math>\alpha</math> increases further, but this increase is now associated with a decrease of the sand transport rate. The resulting sand accumulation downdrift of <math>x_s</math> causes the small initial bulge to grow, and to evolve into a flying spit. </small>]]</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Sand spits may also develop on a straight shoreline. This can occur in situations of highly oblique waves (wave incidence angle <math>\alpha > </math>45<sup>o</sup>), as shown in Fig. 4. At the updrift side of a very small initial shoreline bulge, the littoral drift increases (the wave incidence angle <math>\alpha</math> becomes smaller), whereas at the downdrift side <math>\alpha</math> increases and the littoral drift decreases. A very small initial bulge will therefore grow. The resulting shoreline protrusion is called a flying spit. It will not continue growing perpendicular to the shore, but it will be bent along the shore by cross-shore sediment transport and overwash processes. In Fig. 1 several examples of flying spits are visible. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">Several studies show that simple mathematical models that couple shoreline evolution to longshore sediment transport are capable to simulate the development of flying spits in the way described above<ref>Ashton, A. D. and Murray, A. B. 2006. High-angle wave instability and emergent shoreline shapes: 1. Modeling of sand waves, flying spits, and capes. J. Geophys. Res. Earth Surf. 111: 1–19</ref><ref>Roelvink, D., Huisman, B., Elghandour, A., Ghonim, M. and Reyns, J. 2020. Efficient Modeling of Complex Sandy Coastal Evolution at Monthly to Century Time Scales. Front. Mar. Sci. 7:535</ref>.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">A straight shoreline subject to highly oblique wave incidence is inherently unstable, as explained in the article [[Stability models]]. Different types of shoreline structures may arise, depending on the type of morphodynamic feedback. Self-organized shoreline structures can also develop at low-angle wave incidence, triggered by other processes, such as wave refraction in the surf zone. Examples are discussed in the article [[Rhythmic shoreline features]].  </ins></div></td></tr>
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<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Related articles==</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Related articles==</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>:[[ Littoral drift and shoreline modelling]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>:[[Littoral drift and shoreline modelling<ins class="diffchange diffchange-inline">]]</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>:[[ Natural causes of coastal erosion]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">:[[Stability models]]</ins></div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>:[[ Classification of sandy coastlines]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">:[[Rhythmic shoreline features</ins>]]</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>:[[ Typical examples of structural erosion]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>:[[Natural causes of coastal erosion]]</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>:[[ Sand by-pass systems]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>:[[Classification of sandy coastlines]]</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>:[[Typical examples of structural erosion]]</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>:[[Sand by-pass systems<ins class="diffchange diffchange-inline">]]</ins></div></td></tr>
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<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">==References==</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline"><references/></ins></div></td></tr>
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<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">{{author</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">|AuthorID=120</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">|AuthorFullName=Job Dronkers</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">|AuthorName=Dronkers J}}</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">[[Category:Physical coastal and marine processes]]</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">[[Category:Beaches]]</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">[[Category:Morphodynamics</ins>]]</div></td></tr>
</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Sand_spit&diff=78970&oldid=prevDronkers J at 21:09, 2 April 20212021-04-02T21:09:16Z<p></p>
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<td colspan="2" style="background-color: #fff; color: #222; text-align: center;">Revision as of 21:09, 2 April 2021</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l5" >Line 5:</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>[[File:SandSpitsSenegalRiverNov2020.jpg|thumb|300px|left|Sand spits at the mouth of the Senegal river<del class="diffchange diffchange-inline">. The littoral drift is from north (top) to south</del>. The turbid Senegal river plume is clearly visible. The spit at the upper part of the image is the tip of the "Langue de Barbarie".]]</div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>[[File:SandSpitsSenegalRiverNov2020.jpg|thumb|300px|left|Sand spits at the mouth of the Senegal river. The turbid Senegal river plume is clearly visible. The spit at the upper part of the image is the tip of the "Langue de Barbarie"<ins class="diffchange diffchange-inline">. The orientation of the wave crests indicates oblique wave incidence from the north, implying north-to-south littoral drift. Other notable features are: an ebb shield at the river mouth; an ebb [[Deltas|delta]] at the southern inlet ; so-called "flying spits" around the river mouth; cuspate [[rhythmic shoreline features]] on the landward side of the spit. Google Earth image</ins>.]]</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Notes==</div></td><td class='diff-marker'> </td><td style="background-color: #f8f9fa; color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Notes==</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>Sand spits are ubiquitous on sandy coasts with strong littoral drift; they usually develop where the coastline bends inland from the longshore drift direction. The tip of the spit is <del class="diffchange diffchange-inline">normally </del>curved in onshore direction, <del class="diffchange diffchange-inline">which is mainly </del>due to overwash: sand washed over the spit by overtopping waves and deposited at the leeside. Sand spits can block river outflow, causing the river mouth to migrate in downdrift direction. A famous example is the "Langue de Barbarie", a sand spit that forces the mouth of the Senegal river several tens of kilometers to the south. The spit is breached incidentally in situations of exceptional river discharge. After every breach, the spit resumes its growth of several hundred meters per year.  </div></td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Sand spits are ubiquitous on sandy coasts with strong littoral drift; they usually develop where the coastline bends inland from the longshore drift direction<ins class="diffchange diffchange-inline">. The spit follows the longshore direction of the updrift coast</ins>. The tip of the spit is <ins class="diffchange diffchange-inline">typically </ins>curved in onshore direction, due to <ins class="diffchange diffchange-inline">phenomena such as: </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*</ins>overwash: sand washed over the spit by overtopping waves and deposited at the leeside<ins class="diffchange diffchange-inline">; </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">* incidental changes in the wave incidence direction; </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">*  flood currents around the tip of the spit</ins>.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color: #222; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>Sand spits can block <ins class="diffchange diffchange-inline">the </ins>river outflow, causing the river mouth to migrate in downdrift direction. A famous example is the "Langue de Barbarie", a sand spit that forces the mouth of the Senegal river several tens of kilometers to the south <ins class="diffchange diffchange-inline">(see the figure)</ins>. The spit is breached incidentally in situations of exceptional river discharge. After every breach, the spit resumes its <ins class="diffchange diffchange-inline">southward </ins>growth of several hundred meters per year.  </div></td></tr>
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</table>Dronkers Jhttps://www.coastalwiki.org/w/index.php?title=Sand_spit&diff=78937&oldid=prevDronkers J: Created page with " {{Definition|title= Sand spit |definition= Accretionary feature formed by littoral drift, consisting of a long narrow accumulation of sand or gravel, lying generally in l..."2021-03-31T18:38:52Z<p>Created page with " {{Definition|title= Sand spit |definition= Accretionary feature formed by <a href="/wiki/Littoral_drift" title="Littoral drift">littoral drift</a>, consisting of a long narrow accumulation of sand or gravel, lying generally in l..."</p>
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{{Definition|title= Sand spit<br />
|definition= Accretionary feature formed by [[littoral drift]], consisting of a long narrow accumulation of sand or gravel, lying generally in line with the coast, with one end attached to the land and the other projecting into the sea or across the mouth of an [[estuary]] or [[lagoon]]. }}<br />
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[[File:SandSpitsSenegalRiverNov2020.jpg|thumb|300px|left|Sand spits at the mouth of the Senegal river. The littoral drift is from north (top) to south. The turbid Senegal river plume is clearly visible. The spit at the upper part of the image is the tip of the "Langue de Barbarie".]]<br />
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==Notes==<br />
Sand spits are ubiquitous on sandy coasts with strong littoral drift; they usually develop where the coastline bends inland from the longshore drift direction. The tip of the spit is normally curved in onshore direction, which is mainly due to overwash: sand washed over the spit by overtopping waves and deposited at the leeside. Sand spits can block river outflow, causing the river mouth to migrate in downdrift direction. A famous example is the "Langue de Barbarie", a sand spit that forces the mouth of the Senegal river several tens of kilometers to the south. The spit is breached incidentally in situations of exceptional river discharge. After every breach, the spit resumes its growth of several hundred meters per year. <br />
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Many back barrier lagoons with highly variable river inflow experience seasonal closure of the sea outlet by growth of the spit in periods of drought. The spit is breached at high river discharge, but the coastal zone around the lagoon may be flooded before the outlet is fully restored.<br />
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==Related articles==<br />
:[[ Littoral drift and shoreline modelling]]<br />
:[[ Natural causes of coastal erosion]]<br />
:[[ Classification of sandy coastlines]]<br />
:[[ Typical examples of structural erosion]]<br />
:[[ Sand by-pass systems]]</div>Dronkers J