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When overwhelm waters from the Mississippi River and its tributaries surge overmaster the river the volume of water is physically impossible to contain. In general, there is further to much WaterThe pools behind the navigation close ups have no force in preventing or causing floods. Like a bathtub it doesnt matter if the pools are empty or full when the floodwaters come. Within a very short time the excess water screw bring into being an over flow (Army corps of Engineers).What is a Flood?A flood occurs when water is poured over the land and the ground and rivers endurenot cope with it (Waterlow 8). Once a basin has filled, water allow overflow its rim and resume its downward progress. Gravity ensures that water must drain the land into the ocean (Allaby 12). When snow melts from a divide it is joined by more snow, and it will eventually reach the low lands. Hills down below will in any case shed water into the same low lands and if there is enough of this it can resoluti on in a flood (Allaby 12). The Mississippi, Missouri, and Ohio drain an area of 1,243,700 upstanding miles, this goes from the Rocky Mountains to the Canadian boarder and Pennsylvania (Allaby 13). All of this watershed result in floods each year the snow up north melts. How a Dam Affects FloodingA dekametre is make to make pools at least 9 ft. deep so that barge traffic can navigate freely through out the river. A lock is made so the barges can move from one pool to another (Army Corps of Engineers). The combination of these two make up a lock and dam system. Between St. Anthony Falls, MN, and Granite City, IL there are 29 lock and dam systems. It is said, in the beginning of this page in fact, that dams do not rig flooding. Dams werent made to control floods and they never will, beca engage floods are so irregular and so uncontrollable (Army Corps of Engineers). What is a DikeA dam is an embankment built to control or hold back the water of a river, stream, sea, etc. (Waterlow 2 5). In building a dike you can use sandbags, dirt, or both put together. You will build up a wall, getting it as compact as possible, as high as you think is needed to hold back the floodwaters. In the Netherlands farmers have apply dikes to protect their farms from floods for hundreds of years (Waterlow 25).