Tacoma Power's new innovative fish passage system is under construction at the Cushman Hydroelectric Project. Here's how it will work:
Fish-friendly adult fish trap: Fish will enter through the slot on the lower left of the diagram. They will be attracted by the water discharged from the new turbines. (Arrows show direction of water flow.)
Adult fish passage
Adult fish migrating up the North Fork of the Skokomish River will approach the fish trap at the base of Cushman Dam No. 2. The fish, attracted by flowing water, will enter through the slotted fish entrance. The water will be routed from the turbines in the new powerhouse up through a screened floor of the fish trap.
Once in the trap, fish will be moved into a transport hopper and lifted to the top of the dam on a tram. There a new fish handling system will be used to separate, count and mark (as necessary) the fish. We will transport the fish to their final destination upstream of the two Cushman dams.
Juvenile fish passage
As young fish begin their downstream migration to the ocean, they will be captured in Lake Cushman with a large floating fish collection facility called a floating surface collector.
We will transport the juvenile fish by truck to the top of Cushman No. 2 Dam and place them in a transport hopper. The fish will be gently lowered on the tram to the bottom of the dam and released into the North Fork Skokomish River to continue their journey to the Pacific Ocean.
Installing a cofferdam to contain sediment and elevated pH water during concrete pours
Blast mats
Final excavation for powerhouse and fish collection facility
Swinging in frame to construct fish collection facility above water on platform
Fish collection facility being constructed on platform
Fish collection facility prior to jacking frame installation
Fish Collection Facility lowered into position
Hatcheries
Tacoma Power is designing two new hatcheries as part of the Cushman Hydro Project license and has formed a team to help guide the design. The team includes representatives of:
- Tacoma Power
- Skokomish Tribe
- Washington Department of Fish and Wildlife
Tacoma Power's sockeye hatchery will be located adjacent to Saltwater Park on Hood Canal. Once the hatchery is operational, it will raise two million sockeye each year.
The fry will be released in Lake Cushman, and smolts will be collected and released into the lower North Fork Skokomish River. Returning adult sockeye will eventually be collected at the base of Cushman Dam No. 2.
Design and planning of the hatchery will continue in 2012. Hatchery construction is planned to be complete in spring 2015.
North Fork Skokomish Hatchery
This hatchery will be located at Lake Kokanee and will raise:
- 375,000 spring Chinook fingerlings and yearlings
- up to 35,000 coho smolts
- up to 15,000 steelhead smolts
- build a new floating fish collection facility in Lake Cushman to collect smolts ready to migrate to the ocean
- release collected smolts in the North Fork at the base of Cushman No. 2 to continue their migration
North Fork powerhouse construction - more clean, renewable energy
Tacoma Power is building a new powerhouse at the base of Cushman No. 2 Dam. The powerhouse will capture the energy of the water released into the North Fork of the Skokomish River and produce enough clean, renewable electricity to power about 1,700 Northwest homes.
The powerhouse is a two-story concrete structure and includes a new penstock that taps into an existing 78-inch penstock between a butterfly guard valve and a butterfly discharge valve. The powerhouse will contain two Francis turbine-generator units, each with approximately 1.8 MW capacity.
We estimate that these units will produce approximately 23,500 MWh in annual generation. The electricity from the new powerhouse will be transmitted to the existing overhead transmission line, connecting the Cushman No. 1 and No. 2 powerhouses using underground cables.
Recreation improvements
More camping opportunities will be coming to Big Creek Campground, a U.S. Forest Service campground near Lake Cushman, in the coming years.
Tacoma Power has plans in the works to construct 41 new RV and tent campsites, two kitchen shelters and interpretive and biking trails at the campground. We will also add a new water system.
Other improvements are planned for the day-use recreational sites along Staircase Road, Mount Rose trailhead access road and parking area, and Bear Gulch day-use site.
Once we receive approval from the Federal Energy Regulatory Commission on our plan, we can create a schedule and begin the work.