Water School

A 10-year flood is a high streamflow that overflows the natural or artificial banks of a waterway and has a 10% chance of occurring in any given year.

Datum is the basis for relating a river's stage to mean sea level. (datum + stage = elevation in feet above mean sea level)

A river's bank is the sloping ground that borders the watercourse and confines the water in the natural channel when the water level, or flow, is normal.

A gaging station is a site on a stream, lake, reservoir or other body of water where observations and hydrologic data such as gage height and stream discharge are obtained.

A 100-year flood is a flood event that it has a 1 percent chance of happening in any given year. The term “100-year” is a measure of a flood’s size, not how often it occurs. Although statistically unlikely, several 100-year floods can occur within the same year or a few short years. It is also called the base flood.