Flood Plains - Revision Sheet


Floodplains revision sheet

A flood plain is the wide, flat area of land on either side of the river in its middle and lower course. A flood plain forms through both erosion and deposition. The river is slow flowing and shallow so it deposits alluvium and when material is deposited on the slip off slope of a meander it gradually builds up over time. When a river overflows its banks, water pours on to the floodplain and as it drains away fine material (alluvium) is deposited. A floodplain is a very fertile area due to the rich alluvium deposited by floodwaters. This makes floodplains a good place for agriculture. A build up of alluvium on the banks of a river can create levees, which raise the river bank.

Meanders move at a very slow rate and over millions of years due to erosion and they never stay in the same position. This is all due to the erosion of the outside of the river and the deposition of the inside of the river and this will happen quicker if the river is fuller because it will be travelling at a faster speed.

Positive uses of floodplains:

The alluvium which is deposited make the floodplain very fertile and it is a good place for agriculture

Its constantly replenished with fresh silt washed down in a flood

Floodplains like car parks and parks aren’t effected badly

Livestock farming benefits from this

Negative uses of floodplains:

The houses that are built of a floodplain constantly get flooded and damaged

Crops will die because of the flooding and it will cost the farmers lots of money because they have just lost their crops

 Business decline

Carlisle a city built on a floodplain