Dear nature lovers,
Greetings from oikos !
Flood and flow are two key characters of a river. During a heavy rainfall, the catchment brings in huge quantities of water into the river and this can exceed its water carrying capacity. In this situation, the water floods the channel and inundates the surrounding landscape.
In drier regions high intensity rainfall in a one place can cause ‘flash flood’ and carried to the further places where no sign of rainfall. The chances of a flash flood are high in dry, semi-arid or deserts areas, because of limited development of the river channel. This makes the landscape unable to carry high intensity rainwater and water spreads quickly as a flash flood.
Floodplains are equally important features of river. The floodplain is the area adjacent to a stream or river which experiences flooding and is made up of sediments brought and deposited by each flood event. It is a natural place for a river to dissipate its energy. A physical resistance to the flow of a river, creates ‘meanders’ which usually form over the floodplains. These meanders slow down the speed of the water and when the channel exceeds its capacity, discharges the water on the floodplain, where it is temporarily stored. Maintenance of floodplains is crucial in flood management. Artificial channelisation of the river in such zones, will have a major impact on wider flooding.
Small and frequent floods are beneficial to recharging ground water. They bring nutrients to the soil making it more fertile. This maintains the ecosystems functionality and improves the biodiversity in the river corridors. In areas of uncertain precipitation, floods bring water into the arid and semi-arid regions. They spread nutrients into lakes and rivers, which can result in improved biomass and fisheries over the next few years. For some fish species, an inundated floodplain forms a highly suitable location for spawning, with few predators and enhanced levels of nutrients or food.
However, these benefits are often overlooked, and floods are considered as a negative phenomenon for humans, especially when settlements are within floodplains. It is important to understand flooding as a natural phenomenon and consider its ecosystem benefits, before putting such land to human use. Damage to property and life can only be eliminated by moving away from the floodplains.
Ketaki & Manasi
With Team oikos !
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