German term (edited): Sandvorsp�lung

- Sand replenishment for coastal defence
Over the last ten years sand replenishment has become widely practiced in Europe. It is used as a way to counteract coastal erosion and to restore or maintain beaches and their facilities (see: Sylt, Germany). The method is a soft engineering alternative, furthermore it is a cheap option (contrary to the "solid" and expensive ones like piers and groins; see: Coastal defence management) and fits more into the natural dynamic character of sandy coasts. Beach and dune nourishment adds a ‘wearing layer’ to absorb coastal energy so that the beach and dunes remain intact. In general, nourishment sand is borrowed in the nearshore zone of the sea, usually by dredging and transported to a discharge location in the vicinity of the beach to be nourished. The material is brought ashore and spread out over the beach. Bulldozers and cranes are used to remodel the fill. The material may be placed under the water, on the beach or in the dune area (5, 6). The management technique has many positive features and benefits, but sand replenishment may have ecological effects, too. This applies both to sand extraction sites and to the nourishment site as well as several indirect effects on the geomorphology and vegetation of the outer dunes (5).
During the extraction the amount of suspended sediment in the water increases, which has adverse effects on many biological processes. Furthermore, benthic organisms locally disappear except for less vulnerable species. The area may be recolonised which often results in a population with less species diversity and less vitality (see: Ringkøbing Fjord, Denmark). In the Mediterranean many projects have damaged underwater ecosystems (see: Posidonia beds), so in Spain the sand is now taken from inland sources (5).
On the nourishment site the original geomorphology, the flora and the fauna may be affected. Furthermore, nourishment sand has characteristics unlike beach sand and can lead to a disturbance of the http://www.coastalguide.org/dune/seashor.html#sand
natural equilibrium between the natural sand and the hydrodynamic or aeolian forces (see: Norderney, Germany and Ameland, The Netherlands) In the case of underwater shore nourishment, the nourished sand may move to the beach or in the foredunes by natural processes without affecting them (see: Natural processes). Because of that this type of nourishment is now preferred (5) (see: The NOURTEC and the RIACON projects on Terschelling, The Netherlands).