n. The artificial replenishment of sand washed away from a beach by coastal erosion
Beach nourishment—also referred to as beach renourishment , beach replenishment or sand replenishment—describes a process by which sediment (usually sand) lost through longshore drift or erosion is replaced from sources outside of the eroding beach. A wider beach can reduce storm damage to coastal structures by dissipating energy across the surf zone, protecting upland structures and infrastructure from storm surges, tsunamis and unusually high tides. Beach nourishment is typically part of a larger coastal defense scheme. Nourishment is typically a repetitive process, since it does not remove the physical forces that cause erosion, but simply mitigates their effects.
The first nourishment project in the U.S. was at Coney Island, New York in 1922–23 and is now a common shore protection measure utilized by public and private entities.
Nourishment is one of three commonly accepted methods for protecting shorelines. The structural alternative involves constructing a seawall, revetment, groyne or breakwater. Alternatively, with "managed retreat" the shoreline is left to erode, while relocating buildings and infrastructure further inland. Nourishment gained popularity because it preserved beach resources and avoided the negative effects of hard structures. Instead, nourishment creates a “soft” (i.e., non-permanent) structure by creating a larger sand reservoir, pushing the shoreline seaward.