Ross P-553

General information

Waterway  Skagit River
Current status   Active license 
Type of facility Conventional Hydro
Type of permit FERC License

FERC information

FERC docket # P-553
FERC project name Skagit River
Other projects with this FERC number
Permit issued 5/11/95
Permit expiration 4/26/25

Ownership and operation

Owner Seattle City of
Owner type Publicly Owned Utility
Year first online (conventional hydro) 1952
Transmission or distribution system owner City of Seattle - (WA)

Power and generating capacity

Number of units 4
Total capacity from hydraulic turbine-generator units within each plant 450.0 mW
Average annual net hydropower generation 731,850.7 mWH


The Skagit River Project is in northern Washington State and consists of three power generating developments on the Skagit River – Ross, Diablo, and Gorge – and associated lands and facilities. The Project generating facilities are in the Cascade Mountains of the upper Skagit River watershed, between river miles (RM) 94 and 127. Power from the Project is transmitted via two 230-kilovolt (kV) powerlines that span over 100 miles and end just north of Seattle at the Bothell Substation. The Project also includes two City Light-owned towns, an Environmental Learning Center (ELC), several recreation sites, and several parcels of fish and wildlife habitat mitigation lands.

The Ross Development is one of three developments that make up the Skagit Hydroelectric Project located on the Skagit River in Whatcom County, Washington. Ross Reservoir extends about 1 mile into British Columbia, Canada. The Ross Development consists of: (1) a concrete arch and gravity diversion dam rising 540 feet from bedrock to the crest, with two spillways and 12 radial tainter gates; (2) a 11,680-acre reservoir with a total capacity of 1,435,000 acre-feet; (3) two bifurcated intake structures; (4) two 24.5-foot-diameter power tunnels, 1,800 and 1,634 feet long; (5) four 16-foot diameter penstocks, each 350 feet long; (6) a power plant containing four generating units; (7) two 230-kilovolt (kV) transmission lines extending from the power plant to Diablo Switchyard; and (8)appurtenant facilities.

A multi-part investigative journalism series was conducted on this project in 2021, highlight concerns of the Upper Skagit Indian Tribe. Watch part 1 below, and see the rest on YouTube.

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