Erosion types, illustration. Three types of erosion are shown here: water flow erosion (top), mass movement (centre), and coastal erosion (bottom). At upper left, surface water (from rainfall) is eroding hillsides, and rivers are carrying sediment away downhill and downstream (yellow arrows). At upper right, a river carves a valley from a landscape, with the river broadening as it reaches the sea, slowing and dumping its sediment load in an estuary. At centre left, rock masses on a steep slope eventually give way during a landslip or landslide (centre right, yellow arrows), with debris accumulating at the base of the landslip. At lower left, waves and a prevailing wind direction (blue arrow) erodes the base of a cliff. The cliff collapses and the sediments are moved along the shoreline ('longshore drift' of sediments, yellow arrow), and are dumped to form new land further along the coast.