Glossary of Watershed Terms

aquifer

An aquifer is a geological formation or structure that stores and/or transmits water, such as to wells and springs.

floodplain

A floodplain is a strip of relatively flat and normally dry land alongside a stream, river, or lake that is covered by water during a flood

flood, 100-year

A 100-year flood does not refer to a flood that occurs once every 100 years, but to a flood level with a 1 percent chance of being equaled or exceeded in any given year

groundwater

Groundwater flows or seeps downward and saturates soil or rock, supplying springs and wells. The upper surface of the saturated zone is called the water table.

groundwater recharge

Groundwater recharge refers to an inflow of water to a groundwater reservoir from the surface. Infiltration of precipitation and its movement to the water table is one form of natural recharge.

non-point source (NPS) pollution

Non-point source pollution is contamination that occurs when rainwater, snowmelt, or other water sources washes off rural fields, city streets, or suburban backyards. As this runoff moves across the land surface, it picks up soil particles and pollutants, such as nutrients and pesticides.

point-source pollution

Point-source water pollution comes from a single point, such as a sewage-outflow pipe.

runoff

Runoff is the part of precipitation, snow melt, or other water source that appears in surface streams, rivers, drains or sewers.

surface water

Surface water is on the Earth's surface, such as in a stream, river, lake, or reservoir.