The Bear River Basin is located in northeastern Utah, southeastern Idaho, and southwestern Wyoming. It comprises approximately 7,500 square miles of mountain and valley lands (2,700 in Idaho, 3,300 in Utah, and 1,500 in Wyoming). The Bear River begins in the Uinta Mountains in Utah and extends 500 miles, crossing state boundaries five times before ending in the Great Salt Lake. It is the largest tributary to the Great Salt Lake and the largest stream in the western hemisphere that does not empty into the ocean. The Bear River ranges in elevation from over 13,000 to 4,211 feet and is unique in that it is entirely enclosed by mountains, thus forming a huge basin with no external drainage outlets.

Project Name Bear River
LIHI Certificate Number 53
LIHI Effective and
Expiration Dates
December 31, 2014
December 31, 2022
Owner PacifiCorp Energy
State Idaho
Location Located in the Bear River Basin in northeastern Utah, southeastern Idaho, and southwestern Wyoming.
Installed Capacity Total: 77 MW
Soda Development: 14 MW
Grace Development: 33 MW
Oneida Development: 30 MW
Average Annual Generation Total: 229.4 GWh
(based on past 30 years)
Soda Development: 28.6 GWh
Grace Development: 135.1 GWh Oneida Development: 60.6 GWh
Facility Type Modified run-of-river
FERC No. 20

Developed and undeveloped agricultural lands throughout the basin, as well as urban areas, are located in valleys along the main stem of the river and its tributaries. The Bear River watershed also includes vast amounts of federal (both Bureau of Land Management and Forest Service) and state lands that serve a range of natural and agricultural functions. The Bear River is a highly regulated system.  The major headwater storage facility is Bear Lake, the discharges from which are primarily for irrigation and flood control.

PacifiCorp operates five hydroelectric developments in the Bear River Basin. Three of the developments—Soda, Grace, and Oneida—are operated under the FERC license for the Bear River Hydroelectric Project No. 20 and are the focus of this application.  Two other projects operated by PacifiCorp include the Cutler and Last Chance hydroelectric projects. The Cutler hydroelectric project is operated under FERC license No. 2420. FERC granted the Last Chance development an exemption from licensing in 1981 due to the project’s small size. A sixth facility on the Bear River, the Cove development, was decommissioned in 2006.

The Soda development is located the farthest upstream on the Bear River, five miles west of the city of Soda Springs in Caribou County, Idaho. The Last Chance development is located on the Last Chance Canal, a diversion from the Bear River that is located four miles downstream of the Soda powerhouse. The Grace development is the next facility downstream and it is also located in Caribou County, Idaho. The Oneida Project is located in Franklin County, Idaho, approximately 6 miles south of Cleveland, Idaho. The Cutler development is located 44 miles downstream of the Oneida project in Utah, near the confluence of several major tributaries.

Oneida dam and reservoir

Oneida dam and reservoir

Soda development

The Soda development consists of a 103-foot-high by 433-foot-long concrete gravity dam with a 109-foot-long integral powerhouse section containing five headgates that supply water to the generating unit penstocks and to a 900-cubic feet per second (cfs)-capacity low-level discharge (Johnson valve). The concrete dam also has a 210-foot-long non-overflow gravity section and a 114-foot-long gated overflow spillway section containing three, 30-foot by 14-foot Taintor gates. A 55-foot-long by 19-foot-high earth fill dam also forms parts of the development. The Soda reservoir (commonly referred to as the Alexander reservoir) has a surface area of 1,100 acres, an active storage capacity of 16,300 acre-feet, and a normal maximum full pool elevation of 5,720 feet. It extends approximately 4.5 miles upstream to just below the Big Spring Creek confluence with the Bear River. The development’s 41-foot by 109-foot powerhouse contains two vertical Francis units, each with an installed capacity of 7 MW and maximum hydraulic capacities of 1,287 and 1,337 cfs, respectively. The development includes a tailrace immediately downstream of the powerhouse with a normal tailwater elevation of 5,641 feet.

Grace development

The original Grace Dam and the existing power facilities and other appurtenant structures were constructed shortly after 1910. A new dam was constructed in 1951 and the original rock-filled, timber-crib dam is now submerged in the forebay just upstream of the 1951 dam. Grace Dam is a rock-filled, timber-crib structure with a concrete core at the base of the structure. The structure stands approximately 51 feet high including the flashboards. The crest length is 180 feet 5.5 inches. The dam creates a 320 acre-feet forebay with 250 acre-feet of usable storage.  A 52-foot- wide intake structure containing eighteen 5-foot by 10-foot screen sections is housed within a concrete stucco building, adjacent to the earth embankment section of the dam. A 26,000-foot- long 11-foot-diameter flowline consisting of 15,000 feet of steel and 11,000 feet of wood stave pipeline conveys water from the intake structure to the surge tanks. There are two surge tanks, one 10 feet in diameter and 38 feet high, located approximately 2.6 miles downstream of the diversion, and the other 30 feet in diameter and 132 feet high, located directly above the powerhouse. Three 90-inch-diameter steel penstocks, equipped with two butterfly valves carry water from the surge tanks to the powerhouse. The powerhouse has three turbine generators rated at 11 MW each for a total plant capacity of 33 MW. Their total hydraulic capacity is 960 cfs. The Grace tailrace includes a short concrete-lined section that transitions to an unlined open channel section approximately 350 feet from its confluence with the Bear River.

Oneida development

The Oneida development includes a 111-foot-high by 381-foot-long concrete gravity dam that includes a 118-foot-long uncontrolled auxiliary spillway, a 66-foot-long non-overflow gravity section, a 99-foot-long gated spillway containing five Taintor gates, and an 86-foot-long gravity section with ice sluices. There is also a 40-foot-high, 1,100-foot-long embankment dam. The Oneida reservoir has an active storage capacity of 10,880 acre-feet and a surface area of 480 acres at an elevation of 4,882.90 feet. A 50-foot-wide by 50-foot-high intake structure, containing six openings fitted with trashracks, transitions to two, 16-foot-diameter circular outlets. A 16-foot-diameter, 2,240-foot-long steel flowline conveys water from the intake structure to a 40-foot-diameter, 142-foot-high surge tank.  Three 12-foot-diameter, 120-foot-long steel penstocks extend from the surge tank to the powerhouse. The Grace powerhouse is 52-feet by 162-feet and contains three vertical Francis units, each with an installed capacity of 10 MW and hydraulic capacities of 1,161, 1,161, and 968 cfs, respectively. The development has a 64- foot-wide by 118-feet-long rectangular channel tailrace.

Soda dam and powerhous

Soda dam and powerhous

PacifiCorp operates the hydroelectric developments on the Bear River in a coordinated manner to meet irrigation demands and generate power.  River flows are generally higher than the natural conditions during the irrigation season (April through October) due to irrigation releases from Bear Lake.  The Soda, Grace, and Oneida developments are usually operated in a modified run- of-river mode during this season; water stored in Soda and Oneida reservoirs may be used to satisfy short-term irrigation demand or to maintain reservoir levels in Cutler reservoir. The Cutler reservoir level must be maintained for environmental protection purposes even when the Cutler facility normally ceases to generate power during the summer low-flow period. Substations containing step-up transformers and circuit breakers are located adjacent to the powerhouses at Soda, Oneida, and Grace. The substations serve as the point of interconnection to the transmission grid system.

Certification History

July 24, 2015: LIHI Executive Director Michael J. Sale, using authority delegated from the LIHI Governing Board, has determined that the Bear River Hydroelectric Project (FERC No. 20) continues to meet the LIHI Certification Criteria. The effective certification date for the Bear River Project is December 31, 2014 for an eight (8) year term, which will expire on December 31, 2022. The additional three years are earned for enhancements to the watershed.

February 3, 2015: The Low Impact Hydropower Institute received a complete and timely application for a new term of Low Impact Certification for the Bear River Hydroelectric project on November 20, 2014.  Please see the application files below.

May 19, 2010: The Bear River Hydroelectric Project has been certified as low impact for a five year term, effective December 31, 2009 and expiring December 31, 2014.

March 3, 2010: The public comment period has been closed.

December 31, 2009: PacifiCorp Energy has submitted an application for certification of the Bear River Hydroelectric Project. A public comment period will remain open for 60 days.