Floods are caused by weather phenomena and events that deliver more precipitation to a drainage basin than can be readily absorbed or stored within the basin. Acre-foot.
Volume of water required to cover 1 acre of land (43,560 square feet) to a depth of 1 foot; equivalent to 325,851 gallons. Cubic feet per second (ft³/s).
A unit of measurement expressing rates of discharge. One cubic foot per second is equal to thedischarge of a stream of rectangular cross section, 1 foot wide and 1 foot deep, flowing water an average velocity of 1 foot per second. Equivalent to 448.8 gallons per minute. Discharge.
Rate of flow--a volume of fluid passing a point per unit time, commonly expressed in cubic feet per second, million gallons per day, or gallons per minute. Drainage basin.
A part of the surface of the Earth that is occupied by a drainage system, which consists of a surface stream or a body of impounded surface water together with all tributary surface streams and bodies of impounded surface water. Land area drained by a stream or river. Flash flood.
The result of heavy or excessive amounts of rainfall within a short period of time, usually less than 6 hours, causing water to rise and fall quite rapidly. Flood.
An overflow or inundation that comes from a river or other body of water and causes or threatens damage. Any relatively high streamflow overtopping the natural or artificial banks in any reach of a stream. Flood frequency.
Refers to a flood level that has a specified percent chance of being equaled or exceeded in any given year. For example, a 100-year flood occurs on average once every 100 years and thus has a 1-percent chance of occurring in a given year. Flood plain.
A strip of relatively flat-lying land that borders a stream and is underlain by sediment carried by the stream and dropped in the slack water beyond the influence of the swiftest current. Flood stage.
The stage at which overflow of the natural streambanks begins to...