BOZEMAN, Mont. (May 16, 2006) — A  planned “flushing flow,” from PPL Montana's Hebgen Dam to the Madison River under the company’s Project 2188 Federal Energy Regulatory Commission license, is planned for Monday (5/22). The increase in flow in the Madison from water released from the dam will flush accumulated sediment below the dam, enhancing fish habitat and water quality.
 
“The last high flow in this area of the Madison was in 1997, which has allowed sediment to build up in the streambed,” said Frank Pickett, senior aquatic ecologist for PPL Montana, owner of the dam. “Fortunately, this year we have a better snow pack in the mountains, and the recent warm weather has made next week a good time to supplement naturally occurring high water.
 
“As a result, in cooperation with Montana Fish, Wildlife and Parks; the U.S. Forest Service; and the Montana Department of Environmental Quality, PPL Montana will conduct a gradual release of water from the dam.”
 
The “flushing flow” release of water will begin Monday and will be gradually increased. The higher flow will level off on Tuesday (5/23) and will continue through Thursday (5/25) and then be gradually decreased starting Friday (5/26), Pickett said. Releases from Hebgen will be back to normal Friday evening or Saturday (5/27) depending on the current flow conditions. To protect the outlet of Quake Lake at the Madison River from erosion, the flow in the river will not be allowed to exceed 3,500 cubic feet per second as measured at the Kirby gauge. On Tuesday (5/16), the flow at the Kirby gauge was 1,800 cfs.
 
The gradual flow ramp up and down is designed to protect small fish and river life at the margins of the stream, Pickett said.
 
A maximum of about 1,500 additional cfs will be released from Hebgen Dam, Pickett said. This may result in a gradual increase of about one foot of river depth. These figures are estimates and will change based on location on the river and the variability in river flow, which can change rapidly this time of year. Fishermen should be aware of the changing conditions and take appropriate precautions.
 
Questions about this flushing-flow operation may be directed to Frank Pickett at 406-533-3445.
 
PPL Montana, a subsidiary of PPL Corporation (NYSE: PPL), has electric generating facilities throughout the state with a combined generating capacity of about 1,200 megawatts. PPL Montana has offices in Billings, Butte and Helena, and employs 500 people. The company operates coal-fired power plants at Colstrip and Billings, as well as 11 hydroelectric power plants along Rosebud Creek and the Missouri, Madison, Clark Fork and Flathead rivers. PPL EnergyPlus, another PPL subsidiary, operates a trading floor in Butte that markets and sells power in the wholesale energy market.