Chelan River Habitat Restoration and Enhancement Project
Summary
The relicensing process for the Lake Chelan Hydro Project brought Chelan County Public Utility District (PUD) together with state and federal resource agencies, tribes and the public on a settlement agreement that reviewed priorities for managing and operating the project.
In November 2006, this 59-MW project was licensed for 50 years by the Federal Energy Regulatory Commission. The project sits on Lake Chelan, a 50-mile long lake of exquisite aesthetic appeal, which provides a unique setting for extensive summer recreation, fishing opportunities, a source of irrigation water for surrounding orchards and vineyards, domestic water for neighboring communities. The lake also serves as a reservoir that powers two hydro generators at Chelan Falls Powerhouse.
Borne from the collaborative settlement agreement was the $16 million Chelan River Habitat Restoration and Enhancement Project that included:
- Restoration of the natural function of the Chelan River, previously bypassed for much of the year as all water ran from the dam through a 2.2-mile penstock to the powerhouse; and
- Addition of habitat in the lower reach of the 4-mile river and tailrace for Chinook salmon and steelhead spawning and rearing.
The Chelan River Habitat Restoration and Enhancement Project was completed in October 2009. It provides for year-round water flow of at least 80 cubic feet per second (cfs) from the dam to restore the natural character of the river and adds nearly four acres of fish habitat in the lower reach and tailrace. Included is a newly constructed channel designed to attract adult fish for spawning and juvenile rearing, new habitat in the tailrace for spawning, and a pump station to provide cold water from the powerhouse tailrace to supplement the 80-cfs year-round flow in the channel.
The innovative approach to the design and creation of the new channel enables Chelan County PUD to meet its environmental stewardship responsibilities while ensuring continued production of clean, renewable hydropower for the Pacific Northwest. The first salmon have already spawned in the new channel and tailrace habitat.
Background
When the Chelan Dam was completed in 1927, flow through the Chelan River was diverted most of the year into an underground penstock that carries the water to the powerhouse near the lower mouth of the Chelan River. Water was only present in the Chelan River during spring runoff when the hydraulic capacity of the two units fed by the penstock exceeded inflows into Lake Chelan and spill at the dam was required to keep the lake level from rising too high behind the dam.
When the relicensing process began on the Lake Chelan Hydro Project in 1998, a mandate from the state Department of Ecology and state and federal fishery agencies ensured that year-round flows to the river system would be restored. This would allow for spawning habitat near the mouth of the river for Chinook and steelhead. During the eight-year licensing process from 1998 to 2006 interested parties collaborated on plans that eventually led to license approval.
Challenge
Goals for the Chelan River Habitat Restoration and Enhancement Project were numerous, with specific focus on how to balance competing needs that had evolved over 70-plus years of previous hydro operations. For instance, Lake Chelan was drawn down through routine hydropower generating operations beginning each fall to make room for the snowpack and to fill the lake as it melted into runoff in the spring and early summer. Property owners and business people in the community wanted high lake levels for longer durations to benefit tourism. Fishery agencies wanted year-round flows re-established in the Chelan River to provide a natural system for cutthroat trout and to enhance spawning habitat for salmon and steelhead at the lower reach of the river. In addition, aesthetic interests had to be considered under the hydropower plant’s 401 Water Quality Certificate from Washington State’s Department of Ecology. All interests were merged with Chelan County PUD’s need to run water through the penstock to generate electricity.
Thus, a method had to be devised that would allow proper water levels in the upper and lower river for cutthroat steelhead and salmon spawning, and that would protect against high spill flows through the river channel in the event of extreme spring runoff or extreme weather events. Also, the plan had to accommodate as much power generation as possible.
Innovation
As part of the Lake Chelan Hydro Project relicensing, the following innovative solutions were completed under the $16 million Chelan River Habitat Restoration and Enhancement Project:
- Re-establish year-round flows in the river adequate for fish, recreation and aesthetics but not so high as to divert too much water away from electrical power generation and make the project economically questionable;
- Enhance river flows where needed by taking water already passed through the powerhouse turbines and pumping it up to the head of the lower reach of the river, thereby using water for both power generation and fishery habitat;
- Find the coldest water available for year-round river flows by creating a new low-level outlet at the dam. The existing intake tunnel for a second penstock installed when the dam was constructed in the 1920s was found to be a suitable new conduit for the coolest water from the bottom of the lake above the dam;
- Expand spawning area at the lower reach of the Chelan River by adding a new precisely designed, man-made channel fed by water from a pump station drawing cool water from the powerhouse tailrace;
- Add new habitat in the tailrace as additional spawning area; and
- Protect newly built spawning habitat by creating structures to divert high spill flows from the dam in spring and summer into the old river channel and bypass the new habitat channel.
Results
Starting October 15, 2009, year-round flows of at least 80 cfs resumed in the Chelan River. A new mile-long trail at the upper reach of the river – directly below the Chelan Dam — affords public access to the river that previously did not exist.
In addition, water now flows through the new habitat channel, where fall Chinook salmon are spawning. More than 250 Chinook salmon redds were counted in fall 2009 and hopes are that steelhead will use it in the spring 2010.
The pump station works and delivers an additional 240 cfs of water to the habitat channel to create flows most suitable for attracting spawning salmon and enabling nest creation.
Power is generated at the twin units in the Chelan Falls Powerhouse, and efficiency has been increased with upgrades and modernizations to the two units, raising nameplate generating capacity from 48 MW to 59 MW overall.
Stakeholder Quotes
“The (Washington State) Department of Ecology is pleased and proud to have been a partner and not just a regulator in this important project. Restoring the lower Chelan River and riparian habitat will allow for fish and wildlife to prosper and provide a unique world class feature that will allow the public and scientists to better understand how restoration can work with a little help from humans. Providing for cool clean water from Lake Chelan year around for the Chelan River, the first time in 80 years, is truly an accomplishment that all parties and the public can appreciate and enjoy for years to come. The restoration project is still a work in progress, but already great things have been accomplished. The restoration project represents the best efforts between state, federal, tribal agencies and the PUD to find workable solutions that add value to our lives. I am proud to have had a small part of making the project a reality.” — Tom Tebb, Director of Central Regional Office, WA Department of Ecology
