5120 x 3407 px | 43,3 x 28,8 cm | 17,1 x 11,4 inches | 300dpi
Data acquisizione:
4 marzo 2007
Ubicazione:
Dordogne, France
Altre informazioni:
Flooding is a natural event. It occurs when there is heavy rainfall that fills rivers, streams, reservoirs and lakes above their normal capacity, or if there are very high river or coastal tides that cause levels to rise or surge. The excess water that gathers cannot be restrained by normal boundaries (such as a river embankment) and follows the path of least resistance. Unlike sudden and sometimes catastrophic flash flooding, river flooding (which often causes more severe damage to property) is relatively easy to predict. The land surrounding a river is called the catchment area or watershed because it collects rainfall and funnels it into the river. During periods of severe rainfall, the river becomes full, the ground of the catchment area becomes saturated and the river overflows at its bank’s weakest points – sometimes with devastating results. Human activity has consequences too. Building and concreting over vast areas of land – particularly in wetlands and floodplains - mean that heavy rainfall is no longer able to be absorbed into the ground. The only place for the floodwater to go is over its normal riverbanks and into areas where it can cause major damage.
