The Project reservoir, Spada Lake, formed by the Culmback Dam, has a gross area of 1,908 acres at elevation 1,450 feet mean sea level (msl) with a gross storage capacity of 153,260 acre-feet. Annually, starting in late July, the pool is lowered to elevation 1,415 feet msl by mid- September to avoid spill later in the fall. This provides approximately 58,500 acre-feet of flood storage for the onset of the October to December wet season. There is no minimum normal operating pool elevation for the Project as operations vary depending on the winter hydrologic conditions.
|Project Name||Henry M. Jackson|
|LIHI Certificate Number||75|
|LIHI Effective and Expiration Dates||April 7, 2011
April 7, 2019
|Owner||Public Utility District No. 1 of Snohomish County|
|Location||Located on the Sultan River in Snohomish County, Washington.|
|Installed Capacity||111.8 MW|
|Average Annual Generation||401,311 MWh (average from 2001-2009)|
|Facility Type||store and release|
The Project uses all inflow to Spada Lake to generate power except for required minimum in- stream flow releases (to protect and enhance fisheries) and any spill at Culmback Dam. Culmback Dam is an earth and rock-filled dam, located at River Mile (RM) 16.5 on the Sultan River, with a crest elevation of 1,470 feet msl. The crest of the dam is 25 feet wide, 640 feet long, and is 262 feet above the original streambed.
A concrete morning glory spillway is located within the reservoir approximately 250 feet from the right bank. This spillway has a 94-foot diameter ogee crest, a 38- foot diameter vertical shaft and a 700 foot horizontal tunnel section.
Reservoir outlet works for normal flow releases consist of two 48- inch-diameter conduits embedded in the concrete plug of the diversion tunnel that join the horizontal tunnel section of the spillway. A 16- inch diameter pipeline runs through the right side of the dam and then along its downstream face to provide 20 cubic feet per second (cfs) minimum flow releases when the spillway tunnel is dewatered for maintenance or safety inspections. The Powerhouse intake structure is located near the left abutment, approximately 250 feet upstream of the dam. The 110- foot-tall concrete structure has three 20-foot moveable panels to allow the selective withdrawal of stored water from various depths to facilitate the control of water temperature in the Sultan River. An unlined power tunnel, extends 3.8 miles from the intake structure through Blue Mountain, to a rock trap to capture materials that fall into the tunnel, before entering the 10-foot- diameter welded steel power pipeline that transports water for 3.7 miles to the Powerhouse located on the lower Sultan River.
A semi-outdoor-type Powerhouse is located adjacent to the left river bank. Two Pelton turbines and two Francis turbines are housed inside on the lower generator floor of the two-story structure. The two Pelton turbines discharge directly into 40-foot-long discharge canals that transport water to the main river channel. The Francis turbines re-route a portion of flow under the river via the Lake Chaplain pipeline to the City’s municipal water supply storage, Lake Chaplain, and to the Diversion Dam to maintain the required minimum in-stream flows between the City’s Diversion Dam and the Project’s Powerhouse. The Sultan River stream flows are measured for compliance at a USGS Gaging Station located about 900 feet downstream of the Diversion Dam. The Diversion Dam has been in place since 1930 and was originally used to divert water from the Sultan River into Lake Champlain for the City of Everett’s water supply. It creates a small impoundment, a few acres in size. Although not used for power generation, this dam was incorporated into the Jackson Project as part of the Settlement Agreement due to the agreement to install fish passage at this dam. When the power conduit or the Lake Chaplain pipeline is not operational, the City’s water requirements can also be met by supplementing Lake Chaplain storage with water diverted from the Sultan River via the Diversion Dam and diversion tunnel to Lake Chaplain.
The District operates the Project consistent with the Spada Lake Reservoir Rule Curves, which allow for a balance of municipal water supply, in-stream flows, incidental winter flood storage, higher lake levels for summer recreation and prevention or reduction of risk of spill, following Chinook fall spawning and steelhead spring spawning. Five “states” of operation are defined, based on water level elevation of Spada Lake.
The PUD and the City of Everett (“City”) filed a joint application with the Federal Power Commission (now the Federal Energy Regulatory Commission,“FERC”) in 1960 to develop what was then known as the Sultan River Project.
From the beginning, the Project was seen as serving two purposes; generating power for the PUD from the waters of the Sultan River and increasing the City’s water supply system to meet growing demands. A license authorizing construction of the Project in two phases was issued on June 6, 1961. On July 6, 1979, the PUD and the City filed an application with the FERC to amend the original license with a revised hydroelectric scenario that the PUD thought was better suited to the regional economic and load demand projections, and to reduce the environmental impacts of the original design. The FERC granted this amendment on October 16, 1981, and construction of generating facilities and raising of Culmback Dam started in 1982. The current operating license for the Project will expire on May 31, 2011. The PUD filed a Notice of Intent and Pre-Application Document with the FERC on December 1, 2005. Thereafter, in accordance with the Integrated Licensing Process, multiple consultation meetings were held with private and governmental stakeholders, resources and issues were identified, and environmental study plans were finalized. Environmental and anthropological studies were conducted to develop the detailed information needed to determine appropriate management actions. The PUD filed its Final License Application on May 29, 2009, with the FERC.
On October 14, 2009, the PUD filed a comprehensive Settlement Agreement (“Agreement”) on behalf of itself, United States National Marine Fisheries Service, United States Forest Service, United States Fish and Wildlife Service, United States National Park Service, Washington Department of Fish and Wildlife, Washington Department of Ecology, Tulalip Tribes of Washington, Snohomish County, City of Everett, City of Sultan, and American Whitewater.
The Agreement resolved among the signatories all issues associated with issuance of a new license for the Project, including, in part, reservoir operations, minimum instream flows, process flows, whitewater boating flows, ramping rates, fish passage, fish habitat improvements, wildlife habitat management, marbled murrelet protection measures, recreation, and historic properties management. The PUD expects the FERC to issue a new license by March 2011 or shortly thereafter.
September 22, 2011: The Henry M. Jackson Hydroelectric Project has been certified as low impact for an eight year term, effective April 7, 2011 and expiring April 7, 2019. Pursuant to Criteria D.2, the District’s dedicated buffer zone which is managed under three management plans focusing on wildlife habitat protection or enhancement, and protection of the impoundment’s water quality, qualifies this Project to receive an additional three years of certification.
March 17, 2011: LIHI received a comment letter from Thomas O’Keefe of American Whitewater. The letter is available to read as a PDF in the “Files” section at the bottom of the page.
March 17, 2011: The public comment period has been closed.
January 17, 2011: The Public Utility District No. 1 of Snohomish County has submitted an application for the certification of the Henry Jackson Hydroelectric Project. The public comment period will remain open for 60 days.