Tuesday, July 24, 2007

Understand Floods

A flood is an overflow of an expanse of water that submerges land, a deluge. In the sense of "flowing water", the word is applied to the inflow of the tide, as opposed to the outflow or "ebb".

It is usually due to the volume of water within a body of water, such as a river or lake, exceeding the total capacity of the body, and as a result some of the water flows or sits outside of the normal perimeter of the body. It can also occur in rivers, when the strength of the river is so high it flows right out of the river channel , usually at corners or meanders. These of course, are not applicable in such instances as sea flooding.

A flood occurs when an area of land, usually low-lying, is covered with water. The worst floods usually occur when a river overflows its banks. An example of this is the January 1999 Queensland floods, which swamped south-eastern Queensland. Floods happen when soil and vegetation cannot absorb all the water. The water then runs off the land in quantities that cannot be carried in stream channels or kept in natural ponds or man-made reservoirs.

Floods almost always follow hurricanes, especially in the coastal cities, and it is the most common type of all natural disasters.



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