Sand spit
Definition of Sand spit:
Accretionary feature formed by littoral drift, consisting of a long narrow accumulation of sand or gravel, lying generally in line with the coast, with one end attached to the land and the other projecting into the sea or across the mouth of an estuary or lagoon.
This is the common definition for Sand spit, other definitions can be discussed in the article
|
Notes
Sand spits are ubiquitous on sandy coasts with strong littoral drift; they usually develop where the coastline bends inland from the longshore drift direction. The tip of the spit is normally curved in onshore direction, which is mainly due to overwash: sand washed over the spit by overtopping waves and deposited at the leeside. Sand spits can block river outflow, causing the river mouth to migrate in downdrift direction. A famous example is the "Langue de Barbarie", a sand spit that forces the mouth of the Senegal river several tens of kilometers to the south. The spit is breached incidentally in situations of exceptional river discharge. After every breach, the spit resumes its growth of several hundred meters per year.
Many back barrier lagoons with highly variable river inflow experience seasonal closure of the sea outlet by growth of the spit in periods of drought. The spit is breached at high river discharge, but the coastal zone around the lagoon may be flooded before the outlet is fully restored.
