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Commentaries and editorials

No Flow at Night at Snake River Dams
to Fill Reservoirs

by Mike O'Bryant
Columbia Basin Bulletin - December 5, 2003

At the request of the Bonneville Power Administration, nighttime flows through lower Snake River dams will be allowed to drop to zero in order to refill the reservoirs during times when the demand for electricity is at its lowest. The U.S. Army Corps of Engineers will initiate the operations for up to six hours tonight during the eight-hour period from 10 p.m. to 6 a.m.

The operation allows the dams to be run for maximum power output and to generate the electricity when it is needed most and then to refill reservoirs when the power is needed least.

BPA's Scott Bettin said at an emergency Technical Management Team (TMT) meeting this week that the federal power marketing agency could move as much as 400 megawatts of energy into high load times and gain as much as $48,000 per day in additional benefits if it can have the flexibility such an operation offers.

Although BPA and the Corps have operated this way at Snake River dams from December 1 through the end of February each winter for 16 years, fisheries managers are objecting this year because adult and juvenile fish are still migrating at the dams.

"If juveniles are migrating, going to zero at night would stop the migration," said Chris Ross of NOAA Fisheries. "For steelhead, zero nighttime flow is not a passage detriment in the lower Snake River."

However, zero daytime flow would delay adult passage, he added.

The Corps has allowed the projects to go to zero flow from December 1 to the end of February on a limited basis since 1987. An agreement between the Corps and fisheries agencies allows for such an operation at night and on weekends when power demand is low, but only if there "are few, if any, actively migrating anadromous fish present in the Snake River," according to the Corps' Water Control Manual. "ůzero riverflow operations are not recommended at Lower Snake River projects when fish are actively migrating in the Snake River."

The definition of "few, if any, actively migrating anadromous fish" has fisheries managers stymied. Some 500 to 6,000 adult salmon and steelhead are typically still migrating in the first few weeks of December, said Russ Keifer of Idaho Fish and Game. Last week and this week, 100 to 250 adult fish were still migrating through the dams each day.

"There is lots of uncertainty and conflicting data, even for going to nighttime flows," said Ron Boyce, Oregon Department of Fish and Wildlife. "I prefer we do a better job of bringing information together before we making this decision."

"This issue comes up every year. I'm surprised we have to look at the data again," Bettin said. He added that the operation is useful when BPA needs it, but it has been used only 3 percent (2000) to 13 percent (2002) of the available time in the last three years. Bettin had also asked for the flexibility to use the operation on weekends in the daytime, something the fisheries managers would not accept.

The differences this year, according to the Corps' Rudd Turner, are that there are more fish in the system this year and they are arriving later in the season. "Still," he said, "BPA needs the flexibility."

TMT had discussed the issue at two meetings this week, Dec. 1 and Dec. 3, but fisheries managers continued to oppose the operation. While TMT had prepared to elevate the decision to the Implementation Team (IT) this week, fisheries managers did not step up to ask IT to decide the issue.

"We cannot biologically support moving to the zero flow option because of the uncertainties," said Dave Wills, U.S. Fish and Wildlife, at the IT meeting, representing the opinion of other TMT fisheries managers. "From a technical perspective, I'm not comfortable while there are that many adults still passing."

However, Wills would not elevate the issue to IT for a decision. Instead, TMT will continue to gather information that demonstrates whether the zero flow option impacts migrating fish.

Related Sites:
Implementation Team:
Technical Management Team:

Mike O'Bryant
No Flow at Night at Snake River Dams to Fill Reservoirs
Columbia Basin Bulletin, December 5, 2003

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