Cushman Hydro Project
Cushman No. 1 Dam was one of the first major dams in the Pacific Northwest. It was symbolically activated in 1926 when President Calvin Coolidge pressed a button in the White House during a ceremony to energize the project.
Located on the North Fork of the Skokomish River near Hood Canal, the dam is 275 feet high and 1,111 feet long and generates enough electricity for about 10,000 homes. The dam created Lake Cushman.
Just downstream is Cushman No. 2 Dam, which was completed in 1930, and formed the 150-acre Lake Kokanee. The dam is 235 feet high above bedrock and 575 feet long. Its powerhouse sits several miles below the dam, overlooking Hood Canal along U.S. Highway 101. The dam generates enough energy to power more than 18,000 homes. We added the North Fork Powerhouse in 2013, which generates enough energy to power approximately 1,700 homes.
Our clean, renewable hydroelectric energy moves from the Cushman Hydro Project to Tacoma on a 40-mile-long transmission line. Stretching the line across the Tacoma Narrows in 1926 was a notable engineering achievement at the time. It spans more than a mile and a quarter between towers in Tacoma and Gig Harbor. The original all-steel conductors were replaced with steel reinforced aluminum conductors in 2007.
- Project Licensing
All four of our hydroelectric projects are licensed separately by the Federal Energy Regulatory Commission (FERC), which was created by the Federal Power Act to ensure safe and efficient operation of power plants across the U.S. Many other agencies, tribes, organizations and stakeholders are also an important part of the licensing process.
In 2010, FERC amended the Cushman Hydroelectric Project license issued in 1998 to include the terms of a settlement agreement that Tacoma Power and other government agencies signed with the Skokomish Tribal Nation in January 2009. The license allows Tacoma Power to operate the Cushman Hydro Project until 2048.
- Settlement Agreements
On Jan. 12, 2009, Tacoma Power, the Skokomish Tribal Nation and state and federal agencies signed a settlement agreement that resolved a $5.8 billion damages claim and long-standing disputes over the terms of an extended license for the Cushman Hydroelectric Project. For details, see the information below:
- Fish and Wildlife Programs and Public Recreation
Along with generating clean, renewable hydroelectric energy, our FERC license includes mandates for:
- Protecting more than 2,700 acres of healthy habitat for elk, deer, eagles, osprey, wood ducks and a variety of other wildlife.
- Public recreation at Lake Cushman, a 4,010-acre reservoir located on the southwestern border of Olympic National Park. The lake has kokanee and cutthroat trout, making it a popular destination for anglers.
- Public recreation at Lake Kokanee.
- Learn more about our programs for Cushman fisheries and wildlife and recreation.
- Take a Tour
Free group tours of the Cushman Hydro Project facilities are available by appointment for school, civic, business and recreational groups during regular working hours. Tour groups meet at the Cushman Powerhouse No. 2, located on Highway 101 near the town of Potlatch, south of Hoodsport.
To make arrangements for a tour, please complete our request form.
Cushman No. 1 Dam
- Year completed – 1926
- River system – North Fork, Skokomish River
- Original investment – $4.26 million
- Type of dam – concrete arch/gravity and embankment
- Height – above riverbed, 235 feet; above bedrock, 275 feet
- Length – 1,111 feet
- Width – top, 8 feet; base, 50 feet
- Volume of concrete in dam – 90,000 cubic yards
- Average flow – 845 cubic feet/second
- Drainage area – 94 square miles
- Reservoir length – 9.6 miles
- Miles of shoreline – 23 miles
- Reservoir area at maximum elevation – 4,010 acres
- Reservoir elevation – full, 738 feet; lowest allowable, 615 feet
- Average annual generation – 127 million kilowatt-hours
- Equivalent number of NW homes served – 10,000
- Number of generators – two 25,000 kilowatt generators
- Installed capacity (nameplate rating) – 50,000 kilowatts
Cushman No. 2 Dam and North Fork Skokomish Powerhouse
- Year completed – 1930
- River system – North Fork, Skokomish River
- Original investment – $8.23 million
- Type of dam – concrete arch/gravity
- Height – above riverbed, 175 feet; above bedrock, 235 feet
- Length – 575 feet
- Width – top, 8 feet; base, 40 feet
- Volume of concrete in dam – 38,000 cubic yards
- Average flow – 852 cubic feet/second
- Drainage area – 100 square miles
- Reservoir length – 2 miles
- Miles of shoreline – 4.5 miles
- Reservoir area at maximum elevation – 150 acres
- Reservoir elevation – full, 480 feet; lowest allowable, 460 feet
- Average annual generation – 233 million kilowatt-hours
- Equivalent number of NW homes served – 18,500
- Number of generators – three 27,000 kilowatt generators
- Installed capacity (nameplate rating) – 81,000 kilowatts
North Fork Skokomish Powerhouse
- Year completed – 2013
- Average annual generation – 22 million kilowatt-hours
- Equivalent number of NW homes served – 1,700
- Number of generators – two 1,800 kilowatt generators
- Installed capacity (nameplate rating) – 3,600 kilowatts
- Latest News
Tacoma Power to conduct annual siren test at the Cushman Hydro Project on April 5
Tacoma Power will conduct its annual emergency siren test on Wednesday, April 5. The siren at the Cushman No. 2 Dam will sound at 1 p.m. and include a announcement of the test. The test will last about 90 seconds.
The test takes place on the first Wednesday of April every year; it is a requirement of the utility’s federal license to operate its dams.
The test sequence will be:
- Recorded voice: “Attention – this is a test of the Cushman emergency warning system. This is only a test.”
- Fluctuating wail for 30 seconds.
- Recorded voice: “This completes the test of the Cushman emergency warning system. This was only a test.”
Mason County Emergency Management will send three messages about the test via the Mason County AlertSense System (the night before, shortly before the test, and then after the test).
Many happy returns: Sockeye come home to Cushman for the first time in 90 years
July 7, 2020, was a day to mark on the calendar for our Cushman fisheries program: our first-ever sockeye returned home!
“We have been patiently waiting since we released our first sockeye into Lake Cushman three years ago,” said Cushman Fish Facilities Manager Andrew Ollenburg. “When I heard the exciting news, I was buzzing – it was super awesome.”
The Cushman Hydroelectric Project provides clean, renewable electricity via two dams and three powerhouses. However, when the dams were built, they impacted the river and the natural environment.
As part of our federal license to operate the dams, we invested in two hatcheries, adult and juvenile collection facilities, and enhanced fish and habitat monitoring and evaluation programs.
“That fish doesn’t just represent our first sockeye return, that fish is the first one that has touched every Cushman facility,” Andrew said. “Starting at the hatchery, to Lake Cushman, to our juvenile fish collector, to being trucked down to our sorting facility, being sent out into the river via our release tube, returning from the ocean, navigating over Little Falls and ending up in our adult trap, being brought back up to the sorting facility via our tram, then being trucked over to our hatchery. That fish completed the full cycle.”
Sourcing the eggs
Our release goal for sockeye is 2,000,000 each year, but obtaining the eggs has been a challenge.
“Puget Sound Energy’s Baker Lake stock provides us with the eggs, but, due to scarcity issues, they have only been able to provide 250,000 to 500,000 eggs per year, and this year they won’t be able to provide any,” Andrew said. “They are our only option – no other basin that has a large-enough run that could spare any. Thankfully, we had 127 fish return, about half of which are female, so we should have roughly 100,000 eggs.”
Mark it up
The sockeye hatchery has an ultramodern computer-controlled chiller system that enables us to thermally mark sockeye via their otolith bone, located in the ear.
“We don’t know of any other hatchery that has the same level of automated control to mark groups at these granular levels, so our partners are excited to see the data we collect,” Andrew said. “We work in conjunction with the Skokomish Indian Tribe, Puget Sound Energy, natural resource agencies and other stakeholders. These relationships are extremely important to us and to the program’s success.”
Setting up for success
Determining which test groups have the highest survival rates will take time and patience.
“We should have enough data within about five years to know how to set our fish up for the best possible success,” Andrew said.
Andrew says it’s important to remember our role in the basin.
“We don’t decide who gets to fish for what, where, or when – those decisions are made by the Tribes and the Washington Department of Fish and Wildlife,” Andrew said. “Our goal is to be a responsible steward of the environment by reintroducing and restoring fish populations, and this sockeye return is another huge leap toward making that happen.”
- Public Meetings
Cushman Hydro Project Update – Sept. 12, 2019
Cushman Fire Hall | 5 to 7 p.m.
Approximately 33 attendees
- Reservoir Ops
- Recovery planning efforts in the Skokomish Basin; Fisheries and Hatchery Management Plan
- Broodstock collection – progress, status, donor sources
- Fish passage – progress/challenges
- Overview of wildlife, lands and recreation
- Staircase Road and Bear Gulch
- Cultural resources program
USFS Fact Sheet for Staircase Road – September 2019
Cushman Shoreline Management Plan Update – Sept. 20, 2019
Cushman Fire Hall | 4 to 6 p.m.
Approximately 75 attendees
Get more shoreline permitting information at MyTPU.org/CushmanShoreline