What Are Floodplains?

beachYou’ve heard of or have read about the word "floodplain" before, maybe in this site, in news articles, or in any other sites. But what is a floodplain? It is actually a flat area of land that is next to a stream or a river that is frequently or occasionally being flooded. The flat area of land can either be dry or semi-dry area, but as long as water naturally flows in these areas when water levels rise, these areas are considered as floodplains.

The frequent flooding of an area help shape the floodplain itself. But erosion and aggradation are usually the two main elements that create floodplains. There are times when rivers or streams cut deeper into its channel creating a narrow channel with little or no floodplain. There are times, however, that rivers and floodplains have no defined lines. Instead of a clear river bank, the land area on either side of the river or stream is so flat that the water just flow to it from time to time.

Naturally occurring floods from the rivers and streams carry sediments. Depending on the flow of the river, sediments are deposited into the floodplains differently. If the river is both deep and fast, more sediments are carried into the floodplain when the water overflows. Most floodplains are made up of sand, silt, and clay which what rivers normally carry. However, when rivers are really fast, instead of sediments in the form of silt and sand, gravel is deposited in the floodplains. As the river change its position, so do the kind and amount of sediments being deposited.

Mainly due to the rich mineral deposits that are contained in the river sediments, the floodplains support a diversity of ecosystems. Microscopic organisms alone thrive in the organic matter. The decomposition and production of nutrients make the floodplains a vital agricultural piece of land. This is one reason why people form settlements in floodplain areas despite the dangers of being flooded. The land here remains fertile for a long time.

Moreover, people build their homes and even towns on floodplains because water is more valuable in this areas, transportation through the river is cheap, and because it is basically easier to develop a flat land area than a rolling hills one. Because of these reasons, people endure the yearly or more frequent river overflow. To them the danger and inconvenience is worth it.

One of the more prominent floodplains is the one in the lower Mississippi River which is about 16 km (10 mi) across. The floodplain the is fed by the Nile River is another example of a large one. This one is located in the upper part of the Nile Basin. The Ganges and Brahmaputra rivers in India and Bangladesh have caused countless of problems to the millions of people that live in the flood prone areas. The Yangtze River in China is another large river and large floodplain that supports a huge part of the country’s poor population.

 
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