The natural movement of a body of water pushes sediment to the side, creating a natural levee. The banks of a river are often slightly elevated from the river bed. The banks form levees made of sediment, silt, and other materials pushed aside by the flowing water.

What are levees and how are they formed?

Levees are natural embankments which are formed when a river floods. When a river floods friction with the floodplain leads to a rapid decrease in the velocity of the river and therefore its capacity to transport material. Larger material is deposited closest to the river bank.

How are levees formed BBC Bitesize?

Levees are formed by the repeated flooding of the river. When the river floods, the biggest, most coarse material will be dumped close to the river banks. This will continue to build up the levee over time.