Deposition is the processes by which a river drops or deposits the material it is carrying (also known as its load) either in the river channel or on floodplains.

Find out more about river deposition.

Social costs of constructing dams and reservoirs include:

• the displacement of people due to flooding
• the loss of cultural heritage
• the resettlement of large numbers of people
• the health and well-being of affected populations both upstream and downstream

Find out more about hard engineering.

Due to erosion on the outside of a bend and deposition on the inside, the shape of a meander will change over a period of time. Erosion narrows the neck of the land within the meander and as the process continues, the meanders move closer together. When there is a very high discharge (usually during a flood), the river cuts across the neck, taking a new, straighter and shorter route. Deposition will occur to cut off the original meander, leaving a horseshoe-shaped oxbow lake.

Find out more about meanders and oxbow lakes.

Three ways humans can increase the risk of flooding in rural areas are:

• Deforestation
• Intensive farming, leaving fields bare in the winter
• Overgrazing
• Increased use of polytunnels

Find out more about human and physical causes of flooding.

Lateral erosion erodes the banks of the river. This is more common in the middle and lower courses of a river.

Find out more about river erosion.