Water Monitoring Program Aids Fish
The Kokanee salmon and the brown and rainbow trout that inhabit the Missouri River are breathing easier thanks to PPL Montana’s water quality monitoring program.
Since the mid-1990s, Frank Pickett, PPL Montana’s senior aquatic ecologist, has been conducting water quality tests as part of the company’s licensing agreement with the Federal Energy Regulatory Commission for its Madison-Missouri river dams. And every August since 1997, he had been noticing and documenting a dip in the dissolved oxygen levels around the company’s hydroelectric facilities on the Missouri River.
Montana standards call for a minimum of 6 milligrams per liter of dissolved oxygen, and trout typically require 5 milligrams per liter. “We were seeing in the 3 milligrams per liter range, far too low for fish to thrive,” Pickett said.
He determined that the low dissolved oxygen readings were linked to oxygen depletion in the 100-foot deep water in the Bureau of Reclamation’s Canyon Ferry reservoir, about 20 miles east of Helena, Mont., and south of PPL Montana’s Hauser and Holter dams on the north-flowing Missouri.
It turned out that the low oxygen levels were caused by a breakdown of organic matter by aerobic bacteria, which use oxygen to decompose dead algae, zooplankton, leaves and other organic material in the water.
“This is a common problem in deep, stratified lakes,” Pickett explained. “We provided this information to state and federal agencies. It was valuable information for them. Hauser Lake is a popular fishing area, yet nobody was fishing there in August and September. Fish were crowding in areas where the oxygen levels were higher. Something wasn’t right.”
Steve Dalbey, Helena area fisheries biologist with Montana Department of Fish, Wildlife and Parks, said PPL Montana’s research is making a difference.
Last year, as a result of Pickett’s research, the Bureau of Reclamation started injecting air into its hydraulic turbines at its Canyon Ferry dam.
“That solution is raising dissolved oxygen levels up to near state water standards,” Dalbey said. “We’ll be doing more testing over the next few years. But, nine years later and thanks to Frank’s studies and river monitoring, this is turning out to be a very good story.”