What is a Watershed?
What is a Watershed?

A watershed is the area that drains to a common waterway, such as a stream, lake, estuary, wetland, aquifer, or even the ocean. There are over 2,110 watersheds in the continental US or 2,267 watersheds including Hawaii Alaska, and Puerto Rico. It doesn’t matter where you live, everyone lives in a watershed. Each watershed’s residents, businesses and industries are responsible for the health of the watershed’s water resources. The community must consider its actions and resulting impacts on water resources because "we all live downstream.” Careful planning and management with regard to water resources for flood control, fresh water supplies, recreation and stream health are important.

To find out what watershed you live in, click here.

How land is used throughout a watershed affects water quality. Development alters the land which changes the way water is transported and stored. Impervious surfaces (e.g. driveways, roads, sidewalks, rooftops, etc.) and compacted earth associated with development create barriers to rain and snowmelt infiltration. These alterations may also change the physical characteristics of a stream, thereby degrading habitat for aquatic life. The results include:

  • decreased water quality
  • increased volume and velocity of runoff
  • degradation of aquatic life habitat
  • increased frequency and severity of flooding
  • peak (storm) flows many times greater than in natural basins
  • loss of natural stormwater storage capacity in vegetation, wetland, and soil
  • reduced groundwater recharge
  • decreased base flow (the groundwater contribution to stream flow)