PPL Montana will lower the elevation of the Rainbow Dam reservoir near Great Falls starting Sunday (8/23) around noon to allow for maintenance and testing of its Rainbow hydroelectric plant.
The drawdown, expected to take about three days, will reduce the reservoir elevation by 7 feet to about 3,217 feet elevation. While the reservoir is lowered, PPL Montana employees will conduct testing of the plant to help support the upcoming construction of the new Rainbow powerhouse facility.
“We expect to have the reservoir back to its full elevation of about 3,224 feet elevation by the end of the day on Tuesday (8/25),” said David Hoffman, director of External Affairs for PPL Montana.
“We’re working with the State Department of Fish, Wildlife and Parks on this project and don’t expect any major effect on the use of the lake for recreation,” he said. “However, the Rainbow boat launch on Rainbow Dam Road may not be usable for boaters during the lowest elevations of the brief drawdown.”
Boaters and fishermen can call Fish, Wildlife and Parks at 454-5840 for information on the boat launch and other recreational issues.
The drawdown will help assess options for the continued operation of the Rainbow hydroelectric plant during upcoming construction of the new powerhouse. Rainbow Dam provides clean, renewable energy for the region, Hoffman said. It has a generating capacity of 36 megawatts, enough electricity to satisfy the average energy needs of 27,000 typical households.
PPL Montana plans to nearly double the amount of electricity produced at Rainbow by constructing a new powerhouse with a 60-megawatt turbine that has an improved, fish friendly design. Construction of the new $225 million powerhouse is expected to begin later this year.
PPL Montana provides safe, reliable energy from coal-fired power plants at Colstrip and Billings, as well as 11 hydroelectric plants along West Rosebud Creek and the Missouri, Madison, Clark Fork and Flathead rivers. It has a combined generating capacity of more than 1,200 megawatts and has offices in Great Falls, Billings, Butte and Helena. PPL Montana and its 500 employees are dedicated to Montana and its communities, supporting educational, environmental and economic development programs across the state. PPL EnergyPlus operates a trading floor in Butte that markets and sells power for PPL Montana in wholesale and retail energy markets throughout the western United States. PPL Montana and PPL EnergyPlus are subsidiaries of PPL Corporation (NYSE: PPL).