Cross-section of a river meander

How floodplains and levees are formed

How deltas are formed A delta is a low-lying, flat, marshy land where a river meets a sea or lake. - river carrying a lot of mud and silt at the lower course. - loss of velocity leads to deposition of mud and silt. - build up of deposited mud and silt creates a delta. - continued deposition will block the main channel, which then leads to the formation of distributaries.

Types of delta Cuspate delta – pointed like a tooth or cusp, for example the Ebro and Tiber deltas, shaped by regular but opposing gentle water movement. Arcuate delta, or fan-shaped – these are found in areas where regular longshore drift or other currents keep the seaward edge of the delta trimmed and relatively smooth in shape, such as the Nile and Rhône deltas. Bird’s-foot delta – where the river brings down enormous amounts of fine silt, deposition can occur in a still sea area, along the edges of the distributaries for a very long distance offshore, such as the Mississippi delta.