During 2005, Tacoma Power completed the construction of 100 acres of elk forage fields, located on its upper Nisqually River wildlife lands. The forage fields were constructed to help offset the anticipated trend in reduced elk forage on nearby National Forest lands.
The Nisqually River originates at the Nisqually Glacier in Mount Rainier National Park. It flows 78 miles to its confluence with Puget Sound at the Nisqually estuary, located within the Nisqually National Wildlife Refuge. From its origin at the Nisqually Glacier, the river flows through forested, mountainous terrain where the Nisqually River Hydroelectric Project is located. Downstream of the Project, the Nisqually River flows through the Fort Lewis Military Reservation and the Nisqually Indian Reservation. It then enters Puget Sound near the site of the first European settlement in the region.
Tacoma Power owns and operates the Nisqually River Hydroelectric Project. The Project is located on the Nisqually River between river mile (RM) 40.8 and RM 51.6, approximately 27 miles downstream from its headwaters in Mount Rainier National Park. The Project consists of two developments, Alder and LaGrande. Each development includes a dam, power tunnel and/or penstocks, powerhouse, and associated power transmission system. Overall, the Nisqually River project generates enough power to service 40,500 homes. Hydropower generation from the Nisqually River project avoids approximately 84,000 metric tons of carbon emissions each year (based on 1999 emissions data).
The LaGrande development was built by Tacoma in 1912 and expanded in 1941. The LaGrande development consists of a 192-foot-high concrete gravity dam impounding LaGrande reservoir. The reservoir, situated in a deep narrow canyon, has a surface area of 45 acres. The dam diverts flows into a 6,400-foot-long tunnel that terminates at the LaGrande powerhouse, which houses five generating units with a total generating capacity of 64 megawatts (MW). The water diversion at LaGrande dam creates a 1.7-mile-long bypass reach in the LaGrande canyon.
The Alder development includes a 285-foot-high concrete arch dam impounding Alder Lake from RM 44.2 to RM 51.6, creating a 7.4-mile-long reservoir with a maximum surface area of 3,065 acres. Public and private recreational facilities are located on Alder Lake. The powerhouse, located at the base of the dam, contains two generating units with a total generating capacity of 50 MW.
Tacoma Power contributes to the health of the South Rainier elk herd by establishing and maintaining elk forage fields. A change in the management of the surrounding National Forest lands, causing an increase in mature forest, has reduced the amount of forage available for elk during critical winter months.
The Nisqually River project was relicensed by the Federal Energy Regulatory Commission in 1997. The 40-year license requires Tacoma Power, in addition to power generation, to manage the river corridor for fish, wildlife, and recreation. As part of the license agreement, Tacoma Power acquired and manages 3,300 acres of land for wildlife. Power generation is managed to produce flows and maintain lake elevations that facilitate fish and recreational interests. This process resulted in a coordinated management effort along the Nisqually River corridor.
The elk forage field project is part of Tacoma Power’s mitigation package for the Nisqually River hydroelectric project. The entire package includes a variety of fisheries and recreation enhancements as well as preservation and enhancement of land flanking the river. The wildlife lands are distributed along both sides of the Nisqually River, forming a significant block of protected land buffering more than nine miles of river shoreline. Tacoma Power’s mitigation is directed at offsetting impacts to fish and wildlife associated with the Nisqually River ecosystem. The elk forage fields help off-set forage habitat reductions along the river corridor including habitat inundated by the reservoir. The South Rainier elk herd moves up and down the basin as forage availability changes.
Preservation and enhancement of terrestrial habitat along the river, in conjunction with aquatic enhancements, provide benefits to the entire Nisqually River ecosystem. The elk forage project is one of many enhancement measures along the Nisqually River. Some of Tacoma Power’s other enhancement measures include:
- Stream gravel augmentation;
- Flow augmentation to improve Chinook salmon spawning conditions;
- Kokanee stocking program;
- Flow maintenance for fish spawning in the river’s bypassed reach;
- Reservoir shoreline habitat enhancements;
- Timber stand improvements;
- Wood duck nest box program;
- Wetland/riparian restoration along tributary stream; and
- Gravel pit restoration.
The Nisqually River Hydroelectric Project received the Outstanding Stewardship of America’s Rivers award the past three years. The Nisqually Project has been certified by the Low Impact Hydropower Institute since 2003.
Given the relatively small amount of lands where potential elk forage augmentation is possible, Tacoma Power’s forage fields needed to provide high quality forage, in a remote setting, where a high intensity maintenance program is not practical. Because the Nisqually River wildlife lands are managed for a variety of wildlife, not just big game species, the forage fields must also retain high quality habitat for non-game species.
To maximize elk forage potential without significantly impacting habitat for other native species, Tacoma Power established the fields by integrating them with existing natural features. It created a mosaic of forage fields while preserving high quality habitat areas. A thorough review was conducted to assure the fields’ location and construction minimally impacted existing wetlands and forests. The fields’ design maximizes edges and provides visual screening. After preparation, the fields were seeded with grasses and herbs such as orchardgrass, blue wildrye, red top bentgrass, and clover, which provide high value winter elk forage. To apply the seed and assure a high yield of forage, Tacoma Power worked with the City of Tacoma’s wastewater treatment plant staff, who, using tanker trucks, sprayed the seed mix through a recycled biosolid slurry onto the fields. This proved an efficient and effective means of seeding and forage production. Tacoma Power utilized a seed mix composed of native and non-invasive species. Native fruit-bearing trees and shrubs were also planted around the forage fields to further increase habitat diversity and improve conditions for non-game species. To determine the most effective means of creating forage fields, Tacoma Power established control plots, which were not treated with biosolids. Preliminary results indicate that forage species production is greatest, and bracken fern, a low value forage plant, is less prevalent on the fields that were treated with biosolids.
The fields were constructed with the cooperation of the Washington Department of Fish and Wildlife (WDFW). Tacoma Power constructed the fields in an effort to help meet the Department’s elk management objectives. The need arose when the U.S. Forest Service’s forest management policy shifted towards developing mature forests on the Gifford Pinchot National Forest, which surrounds Tacoma Power’s upper Nisqually wildlife lands. Tacoma Power’s innovative approach also involved coordination with the City of Tacoma wastewater treatment plant. This cooperative effort provides an opportunity for the City’s wastewater treatment plant to dispose of biosolids while providing an effective and efficient means for seeding and fertilizing large areas of forage fields in remote locations.
In 2005, not only did Tacoma Power complete installation of 100-acres of forage fields for elk and deer, but also redesigned a 5-acre field to improve forage productivity. Tacoma Power planted 200 native fruit-bearing trees and shrubs along the periphery of a previously constructed forage field. Annual monitoring of forage plot conditions and experimental treatments were also completed in 2005. Anecdotal observations indicate that the fields receive frequent and regular use by elk and deer. The fields established using biosolids appear to be especially productive. Results of the annual forage field monitoring are anticipated to support these preliminary observations. The attraction of elk and deer also improve recreational hunting opportunities on the Nisqually wildlife lands. The dense brush and forest, interwoven with the fields, provide ample escape cover and limits animal exposure.
Tacoma Power will monitor and maintain the forage fields for the duration of the Nisqually River Project’s license. It will continue to annually monitor the fields with quantitative vegetation composition surveys and elk/deer presence surveys. Soil analysis will be conducted periodically as needed. To stimulate new growth prior to the winter dormant period, mowing will take place during late summer. Weed control, over seeding, additional application of biosolids for fertilization, and field reconstruction will also occur as needed. Through monitoring and study of the impacts from the various maintenance techniques, Tacoma Power will gather insight on the most effective approach for constructing productive elk forage fields in remote settings.
“The City of Tacoma’s TAGRO Facility has enjoyed a mutually beneficial relationship with Tacoma Power on their Nisqually elk forage field project. Tacoma Power is a major player in consuming our highly treated biosolids products, both liquid and solid. To date, we have applied over 300,000 gallons of liquid, and almost 1,000 cubic yards of solids on the forage fields to simultaneously provide effective fertilization and seed application that directly benefits wildlife along the Nisqually River corridor. This relationship has yielded both public and environmental benefits.” Tom Amundson – Biosolids Coordinator, City of Tacoma Public Works Department
