WA

Cushman 1 P-460

General information

Waterway  North Fork Skokomish River
Current status  Active 
Type of facility Conventional Hydro
Mode of hydropower generation Peaking
Type of permit FERC License

FERC information

FERC docket # P-460
Permit issued 7/25/1998
Permit expires 6/26/2058

Ownership and operation

Owner Tacoma City of
Owner type Publicly Owned Utility
Year first online (conventional hydro) 1926
Transmission or distribution system owner City of Tacoma - (WA)

Power and generating capacity

Number of units 2
Total capacity from hydraulic turbine-generator units within each plant 43.2 mW
Average annual net hydropower generation 130,241.9 mWH

The Cushman Hydroelectric Project is located on the North Fork of the Skokomish River in Mason County, Washington, and occupies U.S. lands within the Olympic National Forest and the Skokomish Indian Reservation.

The project consists of two dams and impoundments on the North Fork of the Skokomish River with associated power tunnels and penstocks, powerhouses, and a 26.8- mile-long primary transmission system.

The Dam No. 1 development consists of a 260-foot-high concrete arch dam that impounds Lake Cushman, a 9.6-mile-long storage reservoir with a 4,058-acre surface area and a 453,350 acre-foot storage capacity at full pool.

The Dam No. 2 development consists of a 230-foot-high concrete arch dam approximately 2 miles downstream of Dam No. 1, which impounds Lake Kokanee, a 128-acre lake with a gross storage capacity of 7,300 acre-feet at full pool.

In January 2009, the City proposed to build a powerhouse which would contain two Francis turbine/generator units- 1.8MW each (for an additional 3.6MW). FERC approved the construction and the settlement and issued a renewed license for until 2048.

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