Презентация на тему "Floods"

Содержание

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  Floods

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  Are the result of prolonged rainfall from a storm , rapid melting of large amounts of snow , or rivers which rise up their levels of water

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  FLOODS

  The river overflowed in several places and huge areas of farming land are now several feet under water . Boats are being to rescue people in nearby villages.

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  What causes Floods?

  Heavy rainfall Huge snow melting Failures of dams , barrages etc., Landslides causing blockage of river Deforestation Storms in the sea

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  The Two Main Floods

  Flash floods Flash floods occur when heavy rainfall persists for only a short time period (usually only a few hours), yet can cause major damage and death due to their sudden arrival. Flash floods can also be caused by dam bursts or overflows. Riverine floods Reverine floods occur when water rises above its natural banks, often caused by snowmelts in combination with prolonged and heavy precipitation. Riverine floods take days, weeks, or months to rise to its max and return to normal, much longer than it takes a flash flood to.

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  Where Do Floods Often Occur?

  Floods occur all over the world, except for in Antarctica. Highlands are also unlikely to be struck by flooding. They often occur in urban areas where water cannot drain into the soil properly. Floods usually affect floodplains, low lying, flat areas near large bodies of water.

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  Destruction by Floods

  Floods can cause major structural damage to buildings, kill plants and animals, destroys habitats, and removes soil. Floods cause many deaths and drown many plants and crops, and hundreds of millions of dollars in damage. Many nutrients in topsoil are brought downstream deposited in the ocean.

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  Other Facts

  Floods account for 40% of all deaths caused by natural disasters. In an average year, floods account for about 200 deaths and $2 billion of damage in the U.S. alone. In 1937 floods removed 300 million tons of topsoil in the Ohio Valley. The flood of Huang river of 1887 killed over a million people

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  Thank you for your attention