A flood is a body of water that covers land which is normally dry. Floods are common natural disasters that can affect millions of people around the world. They destroy houses and buildings, and carry soil away from valuable farming land. Floods can also contaminate drinking water and lead to diseases. They are often caused by rivers, but overflowing lakes and seas can also cause flooding.
Causes:volume, spatial distribution, intensity and duration of rainfall over a catchment.
The capacity of the watercourse or stream network to carry runoff.
Catchment and weather conditions before rainfall.
Ground cover.
Topography.
Tidal influences.