Watershed Facts

What is a Watershed? A watershed is an area of land that contains a common set of streams and rivers that all drain into a larger water body such as the Chehalis River or Grays Harbor.
Here are some facts about the Chehalis Watershed:
- The Chehalis River Basin is the largest watershed that originates entirely within the boundaries of Washington State
- Over 140,000 people call the Chehalis Basin home (as of 2000 Census). 220,000 are projected to live in the basin by 2025
- Water Source: There are no significant areas with snow pack high in our watershed. This means that streams are maintained by groundwater flows and rainfall only.
- Lakes: There are 180 lakes, ponds and reservoirs in the basin
- Streams: There are 3,350 miles of rivers and streams in this basin
- Forests: 87% of the land use in the basin is forestry
- Agriculture: 8% of the land in the basin is used for agriculture
Click here to download a document with these and more facts.
Chehalis River Watershed Sub-basins
In addition to the Chehalis River Mainstem there are 11 sub-basins in the Chehalis River Watershed and the Grays Harbor Estuary. Click the name to learn more!
- Black
- Boistfort
- Cloquallum
- HoquiamWishkah
- Humptulips
- Lincoln
- Newaukum
- Satsop
- Skookumchuck
- SouthHarbor
- Wynoochee
- ghEstuary
Salmonids in the Chehalis River Watershed include Chinook, coho, chum, steelhead, bull trout and cutthroat.