PPL Montana plans to build a permanent fish ladder at its hydroelectric dam at Thompson Falls, giving two rare species of trout safe passage into their native spawning waters upstream on the Clark Fork River.

“As part of our federal operating license and our commitment to fisheries and river resources, PPL Montana has filed formal plans for a permanent fish ladder at Thompson Falls,” said Jon Jourdonnais, PPL Montana’s director of hydro licensing and environmental compliance.

“This project is significant because it will reopen hundreds of miles of the upstream Clark Fork River and its tributaries for bull trout, westslope cutthroat trout and other fish,” Jourdonnais said.

Pending approval of the proposal by the Federal Energy Regulatory Commission, construction on the $6 million project is expected to begin in spring of 2009 and be completed in 2010. The project will be funded entirely by PPL Montana.

The fish ladder — which will replace an experimental, temporary fish passage system used since 2003 — will have 47 individual step pools, each filled with water, that will gradually ascend about 75 feet to the top of the dam. Fish will swim their way through the individual pools until they get over the dam.

PPL Montana will place the new system on the north side of the main channel, where years of fish behavior and tracking studies have determined fish congregate below the dam, Jourdonnais said. The location was determined through research from Montana Fish, Wildlife and Parks; the U.S. Fish and Wildlife Service; Montana State Department of Environmental Quality; the Confederated Salish and Kootenai tribes; and fish passage experts.

“This innovative design will attract the fish by having water cascade down the ladder at the dam, causing them to move instinctively toward and into the fish passage system,” he said. “We’re particularly pleased that we can help the bull trout, which is endangered, and the westslope cutthroat trout, a species of special concern.”

There will be a mechanical lift that can be used as needed as part of the ladder operation, where biologists can radio tag and examine the fish, near a spot where the public may view the ladder operations.

“The Clark Fork River at Thompson Falls was originally a natural river falls, and fish would instinctively jump the rock cascade to get upstream,” said R. Mark Wilson, field supervisor with the U.S. Fish and Wildlife Service in Helena. “Working with their community partners, PPL Montana is proposing a plan to provide safe passage for these trout, abundantly found in many rivers before the American West was settled.”

Chris Hunter, chief of fisheries with Montana Fish, Wildlife and Parks, said the state supports PPL Montana’s plans to build the fish ladder at Thompson Falls.

“PPL Montana’s leadership and commitment to protect the endangered bull trout and other species are commendable,” Hunter said. “This project will provide so many benefits to the state of Montana with regards to healthy fish conservation and helping manage healthy native and sport fishing within the Clark Fork River Basin.” 

Thompson Falls is one of two PPL Montana dams west of the Continental Divide – the other being Kerr Dam on the Flathead River, which empties into the Clark Fork. The Clark Fork River empties into the Columbia River, which in turn empties into the Pacific Ocean.

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 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).