Glossary of Flood Terms
Flood Stage: The level at which a body of water begins to flow over its banks and onto dry land, usually expressed in feet above sea level.
Levee, Dike: Mounds of earth and/or fill, such as sand or gravel, piled along a body of water to prevent it from overflowing onto dry land. Dikes are usually small and low, and placed to protect a specific location; levees are high and usually continuous along a stretch of shore or riverbank. Used to protect against floods, as well as "reclaim" land normally covered by water.
Crest: The highest level of water reached by a flooding body of water, after which the water level begins to drop. Most rivers in flood experience multiple crests as additional snowmelt, rain, or obstructions (such as ice, levees or dams) affect their volume and flow.
Did You Know?
At the headwaters of the Mississippi, the average surface speed of the water is 1.2 miles per hour. People typically walk 3 miles per hour.