Moyie Dam

Moyie Dam  The Moyie Dam is located on the Moyie River about one and one-half miles upstream of its confluence with the Kootenai River.  Moyie Dam is a 92-foot-high concrete gravity dam that impounds a small reservoir, approximately one mile long.  The length of the top of the Dam along the walkway at elevation 2040 is 376 feet.

Powerhouses  There are three powerhouses located about 1000 feet downstream. The powerhouses were constructed in 1921, 1941, and 1982 respectively. Four hydroelectric turbines are located in the powerhouses with two units in Powerhouse Two and one unit each in Powerhouses One and Three. The nameplate capacity of the units totals 3950 KW.

Intake and Outlet Works   A 60-inch diameter cast iron slide valve head gate is located behind the Moyie Dam intake trash rack at the entrance to the penstock. When needed, the head gate can be operated by a motor to close the penstock from the fore bay.  The penstock system begins at the head gate with approximately 100 feet of 60-inch steel pipe followed by 650 feet of rock tunnel to a vertical shaft surge chamber.  The upper portion of the surge chamber can be seen adjacent the Project GSU substation.  Beyond the surge chamber, the penstock continues a short distance in 7-foot concrete pipe followed by  60-inch steel pipe into the powerhouse area.  Turbine tailraces at the powerhouses return the penstock water to the Moyie River.  A 72-inch diameter cast iron slide gate valve (drain valve) is located in the bottom of the dam at elevation 1968.5.  If needed, this valve is opened like the head gate with an electric motor for the purpose of lowering the forebay.

Spillway The Dam has an ogee spillway with a crest 17 feet below the top of the dam. The spillway length is 95.5 feet. Piers supporting the walkway divide the spillway into nine segments. A concrete training wall on the spillway separates the spillway flow with four crest segments flowing onto the west half of the spillway and five onto the east. The spillway has the capacity of 19,800 cfs at 2037.5 feet with 2.5 feet of residual freeboard.

Source Information for the Moyie Dam is from the City of Bonners Ferry, Idaho

Libby Dam

Libby Dam  Libby Dam is owned and operated by the Seattle District, U.S. Army Corp of Engineers, and is located in northwestern Montana on the Kootenai River 17 miles upstream of Libby, Montana. Construction on the dam commenced in April 1967 and was completed in July 1973. Construction of the powerhouse began in May 1972 and was completed in July 1976. The dam was dedicated and first power was on line in August 1975.

Libby Dam is a concrete gravity structure designed by the Seattle District, U.S. Army Corps of Engineers. The primary function of the project is to generate hydroelectric power and to serve as flood control for the Kootenai River.

Powerhouse  Power is produced by five 105,000 kilowatt (kw) generators, with space available for three additional units of the same size. Currently a fifth unit is being installed by Allis-Chalmers, Hydro-Turbine Division.

Spillway  The 116-foot-wide spillway is a high head, two-bay ogee-shaped crest controlled by two 48-foot-wide tainter grates which empty into a hydraulic jump stilling basin. The spillway has a design head of 46.4 feet and crest elevation of 2,405 feet National Geodetic Vertical Datum (NGVD) and is capable of discharging 145,000 cubic feet per second (c.f.s.) at maximum regulated pool elevation of 2,459 feet NGVD.

Operation  Reservoir operations are centralized in the Reservoir Control Center (RCC) of the Army Corps of Engineers, North Pacific Division. The physical operation of the project within the approved limits is accomplished by project personnel. Should an emergency occur or appear to be developing, the project engineer or an assistant will promptly contact the RCC to report field conditions and receive instructions. Bonneville Power Administration and other parties upstream and downstream of the project that may be affected by the emergency will also be informed as soon as possible.

Libby Dam Construction

Flood control is an important function of the Libby Dam and Moyie Dam projects.  Their reservoirs are managed to alleviate flooding below the dams, and is a part of the regional flood control system of the Kootenai River Valley. 

Source information for the Libby Dam is from the Emergency Action and Notification Subplan manual. (U.S. Army Corps of Engineers)

Smith Creek Power System  Smith Creek Power System is a power generation station owned by Eugene City Water and Electric, Eugene, Oregon.  The plant has a small diversion dam on Smith Creek and approximately three miles of penstock to the power station.  The power station produces 34 megawatts of power.  The plant is operated and maintained by Dominion, a large company that manages power generation plants.