Friday, September 9, 2022

1924 Gorge Dam and Powerhouse on Skagit River near Newhalem, WA

Dam: (Satellite)
Surge Tank: (Satellite)
Powerhouse: (Satellite)

A railroad bridge and a pedestrian suspension bridge were built during construction of the powerhouse to provide access to the work site.

HAER WASH,37-NEHA.V,1-B-
1. WEST FACADE GORGE POWERHOUSE WITH PEDESTRIAN SUSPENSION BRIDGE TO THE RIGHT AND PRATT TRUSS VEHICLE BRIDGE TO THE LEFT. THE LEFT SECTION OF THE POWERHOUSE WAS ADDED TO THE ORIGINAL 1925 STRUCTURE IN 1949, 1987. - Skagit Power Development, Gorge Powerhouse, On Skagit River, 0.4 mile upstream from Newhalem, Newhalem, Whatcom County, WA Photos from Survey HAER WA-24-B

seattle.gov
The Gorge Dam started supplying power to Seattle City Light in 1924.

HAER WASH,37-NEHA.V,1-B-
8. INTERIOR GORGE POWERHOUSE LOOKING SOUTH AT UNITS 23, 22, AND 21 FROM THE TOP OF UNIT 24. THE SHAW BRIDGE CRANE IS AT THE TOP REAR OF THE POWERHOUSE. THE UPPER SET OF WINDOWS TO THE LEFT ARE FOR THE VISITORS' GALLERY; THE LOWER SET ARE THE POWERHOUSE CONTROL ROOM, 1989.

HAER WASH,37-NEHA.V,1-B-
11. INTERIOR GORGE POWERHOUSE FROM CRANE LEVEL LOOKING DOWN INTO THE STATOR OF UNIT 24 WHICH IS IN THE PROCESS OF BEING REWOUND. THE ROTOR FOR UNIT 24 IS VISIBLE TO THE TOP RIGHT, 1989.

HAER WASH,37-NEHA.V,1-B-
21. REPLACEMENT FRANCIS RUNNER FOR TURBINE FOR UNIT 23 GORGE POWERHOUSE, 1989.

HistoryLink, Photo Courtesy of Seattle City Light
Gorge Powerhouse generators which supplied the first electricity from the Skagit Project to Seattle, 1923
Construction started in 1919 and the first 33mw unit started delivering power to Seattle in Sep, 1924. In 1950, a fourth unit was installed bringing the total capacity up to 120mw. In 1950, they also replaced the wood diversion dam with one made of concrete. The water supply tunnel that was drilled through solid rock is two miles long.

Photo by Kiley Barbero via blog.ncascades
and
ncascades

This shows the route of the 2-mile tunnel between the diversion dam and the powerhouse.
1963 Diablo Dam Quad @ 24,000

The tunnel has four huge penstocks. Note that the entire flow of the river is diverted leaving the Skagit River dry. The power company claims that there were no migatory fish this far upstream before the dam and powerhouse were built. 
hmdb, cropped
"The powerhouse in front of you sent the first electric power from the Skagit Hydroproject to Seattle in 1924.
The rushing water underneath the powerhouse has just [Jan 2019] produced up to 170 megawatts of power, enough to light up almost 9,000 homes.
Visit Gorge Powerhouse’s visitor gallery – follow signs across the pedestrian bridge."
[I have not been able to find any info on the 1980s upgrades. But they did increase the power from 120mw to at least 170mw.]


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