Protection dykes and reinforced dunes

Protection dykes (also referred to as levees) are constructed to protect developments from flood damage. This is particularly important in low-lying coastal areas where developments are protected from the effects of coastal storms by the construction of protection dykes along the coastline (Fig. 20.30). Protection dykes have to be constructed high enough and strong enough to resist the effects of coastal storms, because if they 

One technique to prevent the breach of sand protection dykes is to reinforce them internally using a geotextile tube core, as shown in Fig. 20.30. Here, the geotextile tube prevents the breach of the protection dyke stmcture even if the sand cover is eroded from the exposed side of the protection dyke during storms. After the storm the eroded sand is replaced and the geotextile tube is covered again. Protection dykes internally reinforced with geotextile tubes have been shown to be effective erosion prevention stmctures. 

It is common to use geotextile mbes that blend in well with the surrounding beach environment. The geotextile skin used is normally sand-coloured or has a sand-coloured coating. Furthermore, the use of composite geotextiles has proved particularly beneficial because of sand s abihty to remain embedded within the outer geotextile stmcmre. 

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