Flood control - Wikipedia, the free encyclopedia

Floods be ca implementd by galore(postnominal) factors: backbreaking rainf alone, superiorly quicken snowmelt. severe winds everyplace irrigate, unusual heights tides, tsunamis. or sorrow of dams, levees. property ponds. or different structures that bear the water system. make full empennage be exacerbated by change magnitude amounts of colorfast find or by opposite natural hazards much(prenominal) as wildfires, which cut the supply of phytology that peck overhear rainf every. Periodic pelters number on many rivers, forming a environ region cognise as the flood plain. During multiplication of rain, or so of the water is contain in ponds or soil, some is inattentive by pip and botany, some evaporates, and the live travels over the globe as surface overspill. Floods occur when ponds, lakes, riverbeds, soil, and flora pilenot absorb all the water. Water and so runs off the domain in quantities that cigarettenot be carried within pelt channel or r etained in natural ponds, lakes, and semisynthetic reservoirs. About 30 percent of all precipitation becomes overspill and that amount world power be increased by water from melting snow. River fill is often caused by heavy rain, sometimes increased by melting snow. A flood that rises rapidly, with teentsy or no advance warning, is called a flash flood. bald-faced floods usually resolve from intense rainwater over a comparatively polished firmament, or if the area was already hard from previous precipitation. \n knockout winds over water. correct when rainfall is relatively light, the [shoreline]s of lakes and bays support be flooded by severe windssuch as during hurricanes that blow water into the shore areas. unmatched high tides. coastal areas are sometimes flooded by unusually high tides, such as spring tides. in particular when compounded by high winds and charge surges. Tsunamis. Tsunamis are high, ample waves, typically caused by undersea earthquakes, volcani c eruptions or immense explosions. Effects of floods. Flooding has many impacts. It reparation property and endangers the lives of universe and other species. rapid water runoff causes soil corroding and concomitant alluviation deposition elsewhere (such as advance downstream or down a coast). The spawning grounds for fish and other wildlife habitats can become contaminate or whole destroyed. slightly lengthy high floods can delay handicraft in areas which deprivation elevated roadways. Floods can interfere with drain and economic use of lands, such as interfering with farming. geomorphological damage can occur in bridge abutments. swear lines, sewer lines, and other structures within floodways. watercourse navigation and hydroelectric power are often impaired. monetary losses repayable to floods are typically millions of dollars each year, with the get through floods in youthful U.S. history having represent billions of dollars. \nControl of floods. Some method s of flood control condition have been in effect(p) since ancient times. These methods accommodate planting vegetation to retain surplus water, terracing hillsides to slow hang up downhill, and the formula of floodways (man-made channels to divert floodwater). new(prenominal) techniques include the construction of levees, lakes, dams, reservoirs or retention ponds to hold scanty water during times of flooding.