3.3.1. Beach Nourishment

Sub-tidal sandflats and bars, beaches, and sand dunes are natural barriers that reduce the impact of storm surges and waves along the coast [50]. Therefore, beach nourishment is widely used to combat coastal erosion [51]. Other advantages of beach nourishment are to increase and maintain coastal ecosystems, to enhance the potential for recreation, and to preserve the protective values of a coastline against storm surges. Sand-mining for beach-nourishing can be achieved by offshore dredging up to 20–30 km from the coastline, depending on the morphology of the coastal shelf. Furthermore, nourishment sand often comes from the periodic dredging of ports and harbors and is transported to nearby beaches.

The cost of material can vary greatly depending on its origin and associated transportation costs [52]. According to several cases in the United States, costs vary from ~\$5 to \$18/m<sup>3</sup> [17] (Table 5). Nourishment in The Netherlands is estimated at ~\$4–8/m<sup>3</sup> [14] and average numbers for the EU vary from \$5 to \$11/m<sup>3</sup> [15]. Studies in Australia, South Africa, and Vietnam show cost estimates of \$7.7/m3, \$20.8/m3, and \$5.8/m3, respectively [15,53].


**Table 5.** Cost of coastal protection by beaches and dunes.
