1961,1979 2.6gw Chief Joseph Dam and Rufus Woods Lake on Columbia River at Bridgeport, WA

(Satellite)

Street View, May 2023

Columbia Basin Research, Image Source: USACE Digital Visual Library. Image File Number: 4900-19. Photographer: Unknown. Date: 1/1/81.
Units 1-16 were constructed in 1961 with a nameplate capacity of 64mw and an overload capacity of 88.3mw.
Units 17-27 were added in 1979 with a nameplate capacity of 95mw and an overload capacity of 109.3mw.
The hydraulic capacity is 219kcfs.
The spillway is 980' (299m) long with 19 gates.

USACE
"Chief Joseph Dam is the second largest hydropower producing dam in the United States."

USACE_hydropower
"Chief Joseph Dam is a 'run of the river' dam which means the lake behind the dam is not able to store large amounts of water. Water coming to Chief Joseph Dam from Grand Coulee Dam must be passed on to Wells Dam at approximately the same rate. With 27 main generators in the powerhouse, it has the hydraulic capacity of 213,000 cubic feet per second (cfs), or 1,593,000 gallons per second.    In the event more water was passed on to Chief Joseph Dam than could be used for power generation, the spillway gates would be opened to pass the excess water. With an average annual flow rate of 108,000 cfs, the Columbia River seldom exceeds the powerplant's capability to pass water. Spilling of water is infrequent at Chief Joseph Dam."

USACE, Seattle District posted

“What the heck am I looking at here?” A lot of hydropower is what. 

It doesn’t look like much to the untrained eye, but this is a "busy" photo of Chief Joseph Dam’s powerhouse. 

Extensive capital improvement work is currently underway at Chief Joseph, near Bridgeport, Wash. on the Columba River.

Seattle District operates and manages USACE’s largest hydropower project and the Nation’s second largest hydropower producing dam. (We like to gloat.)

Zoom in a little and you can see two upper brackets stacked on top of Units 3 & 4, while our General Electric contractors simultaneously work the generator rewind project on Units 7 & 10. 

Also, there's a tiny human for scale near the bottom left, because these units are massive!

Just another day to ensure clean, reliable hydropower makes it to the power grid.

They had to dig a huge power canal on the side of the river in order to get a powerhouse that was long enough to handle the flow of the river. So the spillway is effectively a huge diversion dam.

SpokaneHistorical

Thomas O'Keefe Flickr via hydroreform
hydroreform specifies a capacity of 2.5gw and an annual net output of 11,239gwh.

And this specifies a capacity of 2.6mw. They must be upgrading the units.

USACE, Seattle District 0:25 video

Chief Joseph Dam is the nation’s second leading producer of hydropower, capable of producing over 2,600 megawatts (MW) of electricity – enough to power the Seattle metro area.

Its discharge outflow on the day of this video was approximately 250,000 cubic feet per second (cfs) or 12 MILLION gallons per minute. That’s enough to fill about 170 Olympic sized pools in a minute!

[Or one pool in 2.8 seconds.]

The dam does not have a fish ladder, and the blockage of fish is an issue.