levees and floodplains

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Floodpla ins & levees

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  • 1. Floodplains&levees

2. What is floodplains?
3. Defination ofa flood plain
Adjacent to a stream or a river that experience periodic flooding
A floodplain, is flat or nearly flat land
It includes the floodway, which consists of the stream channel
4. How are Floodplains formed?
5. A river may overflow its banks during times of heavy rain.
The river will deposit materials onto the flood plains when the water loses speed and recedes into the river.
The heavier and coarser sediments are first deposited at the rivers edge followed by the smaller and lighter materials deposited at the outer edge.
6. Uses of floodplains
Floodplains may be used by humans for growing crops
As the silt deposited contains alluvium that is extremely fertile
7. What is levees?
8. Definition of a levee
A levee, is a natural or artificial slope or wall to regulate water levels. It is usually earthen and often parallel to the course of a river or the coast.
9. How are levees formed?
10. river overflows its banks
Theexcess water overflows into the flood plain
When the waterrecedes sediments are deposited
Smaller and lighter sediments are deposited further from the river
Larger sediments are deposited nearer to the river to form levees
11. Heavier and larger sediments deposited to form
the levee
12. Artificial levees may be constructed to prevent coastal floods and river floods.
13. Artificial levees may beformed temporary by usingformed by using sandbags or permanent by earthworks
14. Levees were first constructed in the Indus Valley Civilization (in Pakistan and North India from 2600 BC)
15. credits
http://www.answers.com/topic/levee
http://en.wikipedia.org/wiki/Lev%C3%A9es
http://science.howstuffworks.com/levee.htm
http://architecture.about.com/od/damsresevoirs/g/levee.htm
http://blog.nola.com/levees/2010/01/what_is_leveesorg.html
http://www.knowledgerush.com/kr/encyclopedia/Levee/
http://www.wisegeek.com/what-is-a-levee.htm