Skookumchuck River

Skookumchuck River
Skookumchuck River in Bucoda, WA
Location of the mouth of the Skookumchuck River in Washington
Skookumchuck River (the United States)
Location
CountryUnited States
StateWashington
CountyLewis, Thurston
Physical characteristics
Source 
  coordinates46°42′28″N 122°26′41″W / 46.70778°N 122.44472°W / 46.70778; -122.44472
Mouth 
  coordinates
46°43′10″N 122°58′55″W / 46.71944°N 122.98194°W / 46.71944; -122.98194
Length45 mi (72 km)
Basin size181 sq mi (470 km2)
Discharge 
  locationriver mile 6.4 near Bucoda
  average1,972 cu ft/s (55.8 m3/s)
  minimum40 cu ft/s (1.1 m3/s)
  maximum8,560 cu ft/s (242 m3/s)

The Skookumchuck River is a 45-mile (72 km) long river located in southwest Washington, United States. It is a tributary of the Chehalis River, which is the largest drainage basin located entirely within the state. The name, Skookumchuck, is derived from Chinook Jargon meaning "strong water" or rapids.

The river is home to an earthen embankment, the Skookumchuck Dam, which holds the Skookumchuck Reservoir, the largest water bank in the state. The waters are not for public use though the Quinault Indian Nation retains treaty rights in the dam's basin. The dam and reservoir are under the oversight of TransAlta and is of use to the company's coal plant in the Hanaford Valley which is slated to close in 2025.

The river has lost measurable aquatic and vegetative habitats due to both the dam and farming activity in the watershed. An ecosystem restoration project was established in 2024 to improve the waterway's biome.