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Monitoring Plan for McNary Turbine Operations Critiqued by Mike O'Bryant Columbia Basin Bulletin - April 30, 2004

Salmon managers said at this week's Technical Management Team meeting that a monitoring plan developed by the U.S. Army Corps of Engineers for operating McNary Dam turbines outside the 1 percent efficiency range is insufficient to monitor changes in fish survival at the dam.

They said the plan looks at just one of six mechanisms the salmon managers had previously identified that could affect immediate and delayed mortality of juvenile salmon at the dam when operating outside the one percent efficiency range.

"In our estimation, the monitoring plan does not meet the full breadth of monitoring that would be needed," said Dave Wills of the U.S. Fish and Wildlife Service. "As it exists, it looks only at gatewell problems and we've identified a number of other things that need to be examined."

For now, the critique of the monitoring plan is moot, but it could help the Corps as it further develops the plan when the Bonneville Power Administration decides to operate outside the one percent efficiency band.

At last week's TMT meeting BPA withdrew its plan to operate McNary Dam turbines outside the one percent efficiency range that is recommended by the NOAA Fisheries 2000 biological opinion of the Federal Columbia River Power System. BPA had originally calculated that operating outside the one percent efficiency range could produce as much as $5 million more in revenues from increased generation during the spring and summer. If the dam can operate outside the one percent limit, it can spill less water and put more water through turbines to generate more electricity

BPA had calculated that the falling water supply forecast and resulting lower than average river flows would produce almost no additional revenues when operating outside the BiOp efficiency range.

The BiOp set the operating limits as a result of studies in the 1980s that determined turbine efficiency and fish survival are directly related. However, after re-evaluating the studies, BPA concluded that operating outside the 1 percent efficiency limit at McNary may not result in survival that is different than operating within the 1 percent limit.

In a joint state, federal and tribal fishery letter to Rebecca Kalamasz, the Corps lead for the project, salmon managers identified six mechanisms that should be monitored when the dam is operating outside the one percent efficiency range. They include:

• Increased turbine mortality
• Increases stress and mortality due to turbulent gatewell environments
• Reduced numbers of fish passed through spillways
• Increased delayed mortality
• Increased descaling
• Increased forebay delay due to reduced spill volumes.

The letter was signed by representatives from the Columbia River Inter-Tribal Fish Commission, the Idaho Department of Fish and Game, the Oregon Department of Fish and Wildlife, the U.S. Fish and Wildlife Service and the Washington Department of Fish and Wildlife.

In addition, the letter said that they view the plan to "reduce summer spill and eliminate the 1 percent limits at McNary Dam similarly in terms of expected reductions in fish survival."

The difference between the proposals to reduce summer spill and eliminate the one percent limit is that the summer spill proposal offers mitigation for operating outside the BiOp.

"If removing the 1 percent limit is pursued in the future, we believe that appropriate mitigation measures to offset any and all reductions in survival should be included in any proposal to do so," the joint letter said. "Failing to provide mitigation would reduce the probability of recovering ESA-listed fish, and unjustly burden sport, tribal, and commercial fishers with reduced harvest opportunities for non-listed fish."

One of the areas that requires monitoring is whether increased descaling of juvenile salmon occurs when operating outside the limit. The Corps is currently conducting alternating tests at the dam, operating one generating unit at greater than one percent efficiency and then four units greater than one percent efficiency.

Steve Haeseker of USFWS said at last week's TMT meeting that those tests are producing descaled fish when operating outside the one percent range. "There is a distinctive difference in the pattern of descaling," he said.

However, after a week more of monitoring that began April 16, the Corps' Steve Smith said that the descaling rates seem to be low. He said descaling is occurring in less than two percent of the fish. "We're not seeing things out of the ordinary," he said. "We're keeping a close eye on this, but for now we're not seeing anything out of the ordinary."

Related Sites:
Technical Management Team: www.nwd-wc.usace.army.mil/TMT/index.html