A RIVER PROCESS...

Flooding is described as the over flowing as a river bank into an area where the prevention of flooding is absent. in cities such as Pittsburgh, Oregon, Louisiana, and St. Louis, that are built beside rivers, a frequent threat are built of floods will always be present. These areas also have flat flop plains rich in agricultural soil.

Floods are classified by recurrence interval, which is the average time between floods of a given size. A one hundred year flood is a flood that occurs on an average every one-hundred years. It is possible to have two one-hundred year floods in successive years, or even in the same year.

Flood erosion is caused by a high velocity and volume of water in a flood. Flood erosion can be devastating to a city. By undercutting it's banks, the building and piers may fall into the river. Also railroads and highways can be washed away during floods. Some high waters cover streets, agriculture fields and invade buildings. The effect is that the floods can shorten out electrical lines and back up sewers. Water supply systems may fail and or be contaminated. If a foot of water enters a home, it can ruin wall plaster board, and insulation by creating a soggy mess.

Flood deposits are silt and clay. A new payer of wet mud on a flood plain in an agricultural region can be beneficial. The same mud in a city will destroy lawns, furniture, and machinery. Clean up is slow; imagine shoveling four inches of worm filled mud that smells like sewage in a house. City structure, such as a paved area enhance flooding. Bridges, docks, and buildings built on flood plains can constrict the flow of floods, which as a result increases the water height and velocity . It promotes erosion.

Flood control structures can reduce the dangers of flood waters and sedimentation. Upstream dams trap water and release it slowly after a stream. Protective walls of stone or concrete are constructed along river banks, such as the flood wall in New Orleans along the Mississippi River.

With floods come heavier river channeling of sediments. This means that the river deposits lenses of sandstone in the channels. These sandstones may consist of sand-sized fragments of fine-grained rocks. River channel deposits contain cross bed ripple marks. Flat flood plains beside channels are covered by flood waters, which deposit thin shales, classified by mud cracks and fossils.

Flooding also entails the movement of soil. Soil is a loose material used foe engineering and constructing the earth's material. Rock sedimentation is an important part of flooding because it depends on soil. Rock sedimentation is a revolving procedure that consist of sediment, lithification, sedimentary rock, metamorphism, metamorphic rock or melting, magma cooling, and igneous rock or weathering. The sediment, which is the name for loose material particles originate from weathering erosion of rocks and chemical precipitation from the solution.
 
 
 

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