The mainstem Nisqually River contains two hydroelectric projects, the Yelm project (operated by the city of Centralia, Washington) and the Nisqually River Project (operated by the applicant).  The Yelm project consists of a single diversion dam, canal, powerhouse, and fishway, which allows anadromous fish migrating upstream to pass through the Yelm project and continue to areas immediately downstream of the Nisqually project (FERC 1997a).

Project Name Nisqually
LIHI Certificate Number 8
LIHI Effective and
Expiration Dates
April 15, 2013
April 15, 2018
Owner City of Tacoma
State Washington
Location Located on the Nisqually River in Pierce, Thurston, and Lewis Counties, Washington.
Installed Capacity Total: 114 MW
LaGrande: 50 MW
Alder: 64 MW
Average Annual Generation LaGrande: 228 million KWh
Alder: 345 million KWh
Facility Type LaGrande: Run-of-river
Alder: Peaking
FERC No. 1862

The Nisqually Hydroelectric Project consists of two hydroelectric facilities: the 50 MW LaGrande facility and the 64 MW Alder facility.  Each facility includes a dam, reservoir, flowline, powerhouse, and an associated power transmission switchyard.  Both switchyards lead to a single transmission system that extends 26.2 miles to the City of Tacoma.  The Alder facility is operated in a peaking mode and LaGrande is operated as a run-of-river facility (FERC 1997, Tacoma 2003).

The Alder facility (river mile 44.2) includes a 285-foot-high concrete arch dam that impounds Alder Lake, a 7.4-mile-long storage reservoir with a maximum surface area of 3,065 acres and an operating storage capacity of 161,457 acre-feet at elevation 1,207 feet.  Adjacent to the main dam structure is a reinforced concrete spillway channel with a total discharge capacity of 80,000 cubic feet per second (cfs).  The Alder powerhouse is located at the base of the dam.  The powerhouse contains two generating units (FERC 1997).

The LaGrande facility (river mile 42.7) consists of a 192-foot-high concrete gravity dam impounding LaGrande reservoir.  The LaGrande reservoir has a surface area of 45 acres and contains 2,700 acre-feet of total storage.  The LaGrande reservoir is situated in a deep, precipitous canyon, extending a distance of 1.5 miles to the base of Alder dam.  LaGrande Dam has a large reinforced concrete spillway with an 80,000-cfs capacity.  The dam diverts flows into a 6,400-foot-long underground tunnel, which terminates at a steel penstock leading to a manifold structure serving five individual penstocks for each of five generating units in the LaGrande powerhouse.  The 1.7-mile-long LaGrande bypassed reach is situated in a deep gorge between LaGrande Dam and the LaGrande powerhouse (FERC 1997).

Tacoma maintains about 1,113 acres of project land around Alder and LaGrande reservoirs for project operations and related recreation facilities.  Most of Alder Lake’s shoreline is contiguous with lands of the Mt. Baker-Snoqualmie National Forest, the Washington Department of Natural Resources (WDNR), and Weyerhaeuser Timber Company.  About 177 acres of project lands are dedicated to developed recreation.  Recreational use at the project is confined to the lands and waters of Alder Lake, which includes about 28 miles of shoreline.  Tacoma operates and maintains three recreation facilities on the northern shores of Alder Lake:  Alder Lake Park, Sunny Beach Point Day-use Area, and Rocky Point Day-use Area.  The WDNR also operates and maintains a campground with a boat launch on the south shoreline of Alder Lake (FERC 1997).

The Nisqually project was relicensed in 1997 based on consultations with state and federal resource agencies and the Nisqually Tribe. These consultations resulted in new operating conditions to provide increased minimum flows in the bypassed reach and modified flows overall to provide for minimum flows in the river below the LaGrande powerhouse. There are anadromous fish (salmon species that spawn in fresh water and migrate to saltwater) in the lower portion of the LaGrande bypassed reach. There are historic barriers to fish passage in the LaGrande gorge. The Nisqually Tribe has treaty fishing rights in the Nisqually River, and operates the Clear Creek Hatchery downstream of the project area.


Certification History

March 12, 2014: The City of Tacoma’s Nisqually Hydroelectric Project has been recertified for a third five year term of low impact certification. The effective certification date is April 15, 2013 and it will expire April 15, 2018.

May 15, 2013: LIHI has received an application for recertification of the Nisqually Hydroelectric Project. The application can be found below in the “Files” section.

August 28, 2008: The Nisqually Hydroelectric Project has been recertified for a second five year term of low impact certification, as it continues to meet all of LIHI’s eight environmentally rigorous criteria addressing river flows, water quality, fish passage and protection, watershed health, endangered species protection, cultural resources, recreation use and access, and whether or not the dam itself was recommended for removal.

April 19, 2008: The Low Impact Hydropower Institute has received an application for recertification of the Nisqually Hydroelectric Project, located on the Nisqually River in Washington.

September 17, 2003: The Nisqually Hydroelectric Project has been certified as low impact for a five year term, effective April 15, 2003 and expiring April 15, 2008. It is the third hydropower facility to earn LIHI certification in Washington State, and the eighth nationwide.