June 14, 2010 NOTICE:
PPL Montana announced North Shore Trail closures between Morony Dam and Ryan Dam and the Sulphur Springs trailhead at Morony effective immediately. The temporary closures are for public safety purposes due to transmission line construction activities.
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PPL Montana begins $230 million redevelopment of Rainbow hydroelectric plant
PPL Montana has started of the $230 million project to expand the Rainbow hydroelectric plant for a second century of producing clean, renewable energy.
The project will increase by 70 percent the amount of clean, renewable power generated at the Rainbow facility when this project is completed in 2012. PPL Montana is reinvesting in the state and making responsible use of the state’s valuable natural resources. PPL Montana is recommitting itself to the tradition of renewable energy development that has been part of Montana’s history and the Great Falls area for more than 100 years.
The Rainbow Dam redevelopment is part of the significant investment that PPL Montana is making in the state, one that will create hundreds of local construction jobs, boost the local economy and supply the region with more renewable energy.
PPL Montana will construct a new Rainbow powerhouse. Smaller units, installed between 1909 and 1930 with a combined capacity of 37 megawatts, will be replaced with a single 62-megawatt unit that can generate enough electricity to power about 45,000 homes.
The project, part of PPL Montana’s Project 2188 license with the Federal Energy Regulatory Commission, will also benefit fisheries habitat in the Missouri River. The turbine will have wider flow passages and fewer rotating surfaces, making it easier for fish to pass through unharmed.
PPL Montana also operates the Black Eagle, Cochrane, Ryan and Morony dams on the Missouri River near Great Falls.
© 2010 PPL Corporation
Rainbow Dam
Rainbow Dam, which began operation in 1910, is 1,055 feet long and 29 feet high. Its reservoir is 4 miles long and has a storage capacity of 1,050 acre-feet. The dam is classified as a “run-of-river” project because it can generate electricity using the water that flows down the river, without the need to store additional supplies. Immediately downstream from Rainbow Dam is Rainbow Falls, which has a drop of 47 feet. Further downstream is Horseshoe Falls, with a drop of 12 feet.
Rainbow Dam is one of eight hydroelectric plants and one reservoir along the Missouri and Madison Rivers covered under PPL Montana’s Project 2188 operating license. Through this license, PPL Montana works with state and federal agencies and private groups to implement a diverse array of environmental stewardship projects to protect habitats on or near the banks of the Missouri and Madison Rivers.
For example, PPL Montana contributed $100,000 toward the completion of the Lewis and Clark Overlook and the construction of both the Rainbow and Crooked Falls overlooks near Rainbow Dam. In 2003, the company contributed $150,000 for construction of a pedestrian-bike trail from Rainbow Dam to the Sulfur Springs Trailhead.
The Sulfur Springs Trailhead was made possible in part through a $100,000 contribution from PPL Montana, which continues to contribute $10,000 a year toward operation and maintenance expenses at the site. The company retains and manages as a natural area the lands it owns on the north shore adjacent to the Rainbow reservoir.
Rainbow Dam is part of the Great Falls Portage National Historic Landmark. It is located between PPL Montana’s Black Eagle and Cochrane Dams. The company also operates the Ryan and Morony Dams on the Missouri River near Great Falls.
• © 2010 PPL Corporation
PPL Montana Rainbow Dam Redevelopment Fact Sheet
Company: PPL Montana, Billings.
General Contractor: Walsh Construction Co., Chicago
Project cost: Approximately $230 million, paid by PPL.
Capacity: A single 62-megawatt unit will help provide more clean, renewable energy for the people of Montana. It will replace aging units, installed between 1909 and 1930, which have a combined capacity of 37 megawatts.
Perspective: The new unit will be big enough to power about 45,000 homes.
New powerhouse: A concrete paneled structure, about 160 feet long and 80 feet wide, will be about 200 feet downstream of the old powerhouse.
Downstream Fish Passage: The large single hydro turbine runner, which looks like a ship propeller in a vertical position, will offer wider flow passages and fewer rotating surfaces, making it easier for fish to pass through unharmed. There will also be a new intake structure with an automated trash rake to remove debris and significantly reduce obstacles to fish passage.
Turbine speed: The lower rotating speed of the turbine (approximately 225-240 revolutions per minute to 133-144 revolutions per minute) will reduce turbulence, decrease fish mortality by more than 95 percent and make it easier for fish to pass through safely.
Jobs: The project will result in a peak work force of 200 jobs, paying prevailing wage, for local contractors over the next 30 months.
History: Rainbow Dam, which began operation in 1910, is 1,055 feet long and 29 feet high. Its reservoir is 4 miles long and has a storage capacity of 1,050 acre-feet. The dam is classified as a “run-of-river” project because it can generate electricity using the water that flows down the river, without the need to store additional supplies. Immediately downstream from Rainbow Dam is Rainbow Falls, which has a drop of 47 feet. Further downstream is Horseshoe Falls, with a drop of 12 feet.
About six miles northeast of Great Falls, Rainbow Dam is one of eight hydroelectric plants and one reservoir along the Missouri and Madison rivers covered under PPL Montana’s federal operating license. Through this license, PPL Montana works with state and federal agencies and private groups to implement a diverse array of environmental stewardship projects to protect habitats on or near the banks of the Missouri and Madison rivers.
Other construction/project facts:
• More than a half million tons of earth and rock will be moved during the project.
• More than 50,000 cubic yards of concrete will be poured.
• More than seven million pounds of rebar will be used.
• © 2010 PPL Corporation
Rainbow Dam History & Community Impact
Rainbow Dam is an eight-unit hydroelectric plant on the Missouri River, about six miles northeast of Great Falls. The original units have a total generating capacity of 37 megawatts. (One megawatt can satisfy the average energy needs of 750 households.)
Rainbow Dam, which began operation in 1910, is 1,055 feet long and 29 feet high. Its reservoir is 4 miles long and has a storage capacity of 1,050 acre-feet. The dam is classified as a “run-of-river” project because it can generate electricity using the water that flows down the river, without the need to store additional supplies. Immediately downstream from Rainbow Dam is Rainbow Falls, which has a drop of 47 feet. Further downstream is Horseshoe Falls, with a drop of 12 feet.
Rainbow Dam is one of eight hydroelectric plants and one reservoir along the Missouri and Madison rivers covered under PPL Montana’s Project 2188 operating license. Through this license, PPL Montana works with state and federal agencies and private groups to implement a diverse array of environmental stewardship projects to protect habitats on or near the banks of the Missouri and Madison rivers.
For example, PPL Montana contributed $100,000 toward the completion of the Lewis and Clark Overlook and the construction of both the Rainbow and Crooked Falls overlooks near Rainbow Dam. In 2003, the company contributed $150,000 for construction of a pedestrian-bike trail from Rainbow Dam to the Sulfur Springs Trailhead.
The Sulfur Springs Trailhead was made possible in part through a $100,000 contribution from PPL Montana, which continues to contribute $10,000 a year toward operation and maintenance expenses at the site. The company retains and manages as a natural area the lands it owns on the north shore adjacent to the Rainbow reservoir.
Rainbow Dam is part of the Great Falls Portage National Historic Landmark. It is located between PPL Montana’s Black Eagle and Cochrane dams. The company also operates the Ryan and Morony dams on the Missouri River near Great Falls.
© 2010 PPL Corporation
Project safety
Public safety a priority during construction at Rainbow Dam
To protect public safety during the construction at Rainbow Dam, Cascade County and PPL Montana have closed the Rainbow Trailhead, Rainbow Dam Road past the Rainbow boat launch and the North Shore Trail. The Sulphur Spring trailhead, upper and lower Morony parking lots, and the river access at Morony Dam are also closed.
The Rainbow boat launch will remain open for boating and fishing.
These closures are necessary for public safety and to allow contractors to prepare work sites and move heavy equipment on Rainbow Dam Road and the gravel access road near Rainbow Trailhead. Additional closures may occur as other construction work begins.
River’s Edge Trail maps showing these locations are available at Fish, Wildlife & Parks Region 4 Headquarters; City Parks & Recreation; Great Falls Visitor Center; Knicker Biker; Bighorn Wilderness; kiosks along the River’s Edge Trail; and other locations in the city.
The South Shore trails will not be affected by these closures. Boaters and fishermen can call Fish, Wildlife and Parks at 406-454-5840 for information about recreational issues in the Great Falls area.
The $230 million redevelopment of PPL Montana’s Rainbow hydroelectric plant, which will increase by 70 percent the amount of clean, renewable energy produced there, is expected to be completed in 2012.
The public will be able to view the construction work from the Rainbow and Lewis & Clark Overlooks located 1.5 miles east of Giant Springs State Park on Giant Springs Road, and from the Crooked Falls Overlook on the River’s Edge Trail east of the other overlooks.
© 2010 PPL Corporation |