Types Of Flood Essay

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2.6 Types of Flood There are several different types of floods. Most communities experience only a few of them. Floods are generally grouped into the following types which are riverine flooding, urban drainage, ground failures, fluctuating lake levels and coastal flooding and erosion. 2.6.1 Riverine Flooding When surface water runoff introduced into streams and rivers exceeds the capacity of the natural or constructed channels to accommodate the flow, water overflows the stream banks, spilling out into adjacent low lying areas. Riverine flooding occurs as a consequence. The dynamics of riverine flooding vary with terrain. In relatively flat areas, land may stay covered with shallow, slow-moving floodwater for days or even weeks. In hilly and mountainous areas, floods may come minutes after a heavy rain. The short notice, large depths and high velocities of flash floods make these types of floods particularly dangerous. Among the common types of riverine flooding are: i. Overbank Flooding Overbank flooding of rivers and streams – the increase in volume of water within a river channel and the overflow of water from the channel onto the adjacent floodplain –…show more content…
The National Weather Service defines a flash flood as “A rapid and extreme flow of high water into a normally dry area, or a rapid rise in a stream or creek above a predetermined flood level, beginning within six hours of the causative event (e.g. intense rainfall, dam failure, ice jam). However, the actual time threshold may vary in different parts of the country. Ongoing flooding can intensify to flash flooding in cases where intense rainfall results in a rapid surge of rising flood waters.” Flash floods are also characterized by a rapid rise in water, high velocities, and large amounts of debris. Major factors in flash flooding are the intensity and duration of rainfall and the steepness of watershed and stream

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