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.