US environmental groups say the Bush Administration energy Bill could adversely affect trout fishing streams in Montana's hydro dam reservoirs.

A little-discussed section of the Act requires the US Department of the Interior to maximise the energy output of Bureau of Reclamation dams that produce more than 50MW of electricity.

In Montana, three dams would be affected by this legislation: the Hungry Horse dam on the south fork of the Flathead river, Canyon Ferry dam on the Missouri and the Yellowtail dam on the Big Horn river.

The national conservation group, Trout Unlimited, opposes the legislation because it fears dams would be operated to provide power at peak use times, resulting in flooding of downstream trout fisheries, or leaving trout stranded in small, shallow, warm pools when water is turned off. Bureau of Reclamation dams are currently operated to balance a number of different objectives: irrigation, flood control, electricity production and the maintenance of healthy fisheries.

The new Energy Act changes those objectives by placing a higher priority on the dams’ hydroelectric capabilities.

Other rivers in the west which would be affected include the Green river in Utah, the Gunnison in Colorado, the Lower Sacramento in California, the Colorado below Glen Canyon in Arizona, the North Platte in Wyoming and the South Fork of the Snake river in Idaho.