Tribes Propose Spring/Summer River Flow/Spill Operationsby CBB Staff
Columbia Basin Bulletin - March 21, 2003
Expecting a higher than average number of juveniles to migrate to the ocean this year, but a lower than normal amount of water to flush the juveniles to the sea, the Columbia River Intertribal Fish Commission says it has an answer.
CRITFC published its 2003 river operations plan this week and asked salmon and river operating managers to consider changes to operations to adjust to the low-flow year.
CRITFC expects 35 million to 40 million fall chinook juveniles to migrate from Hanford Reach in the next few weeks -- a 40 percent to 60 percent increase over average years. However, flows are expected to be much lower than normal, although not as low as those the region experienced during the 2001 drought. CRITFC also estimates that 24 million spring and summer chinook juveniles will migrate from the lower Snake River and 2.2 million sockeye juveniles will migrate from the Okanogan River. To help those juveniles traverse Columbia River and Snake Rive dams, it asked for flows that would resemble a natural peaking hydrograph.
"River temperatures are much higher and we have a lot more fish coming out of the basin earlier this year," said Bob Heinith, CRITFC hydro program manager. "We need to protect this productivity Mother Nature provided during good flow years and ocean conditions by safely speeding these juvenile salmon out of the river."
Kyle Martin, hydrologist at CRITFC, told the Technical Management Team this week that the tribes begin working with different operating assumptions than federal agencies. He said the Corps is currently assumes a water supply forecast of about 73 million acre feet, January through July at The Dalles Dam, but that CRITFC believes the water supply this year will be closer to 68 maf.
One difference between the operating agencies' river operating plan and CRITFC's is that the tribes propose a natural peaking hydrograph this spring. According to a graph in its plan, the CRITFC proposal has the river peaking at 360,000 cubic feet per second at The Dalles Dam in late May. CRITFC said the increases in flows should begin in late March and work towards that peak the week of May 26 to June 1. The federal plan has flows in late May at about 240 kcfs.
Heinith said the peaking hydrograph will get smolts to the ocean faster, while creating attraction flows for adults moving upstream to spawn. "It creates a plume of fresh water with sediments in the near-shore ocean environment, which protects juveniles from predators and attracts adults to the river entrance," Heinith said. It also creates more habitat in the river for juveniles, he added.
Martin said that the CRITFC plan finds about 2.2 maf more water in the Columbia River Basin system through changed flood control operations. That requires the reservoirs to operate at a higher elevation than called for by the Corps' flood control rule curves. Those rule curves have been established as a way to balance flood control concerns with the amount of storage needed later for fisheries operations. CRITFC calls for drafting Grand Coulee Dam to an elevation of 1,280 feet to account for flood control in the spring, but no lower even during the late summer, and to refill Coulee by June 30, while the federal plan, he said, could draft Coulee as low as 1,270 feet. Refill under the federal plan is also by June 30.
The water supply forecast by CRITFC assumes that Idaho will be able to provide 427,000-acre feet of water for summer flow augmentation, according to Martin. That is an assumption recently challenged by the Bureau of Land Management that has said low precipitation in the upper Snake River will not allow it to deliver the entire 427 kaf this year. In addition, CRITFC assumes 450 kaf from Idaho Power's Brownlee reservoir, although Idaho Power has not agreed to provide the water. In the recent past, while Idaho Power has provided some water, it has refused to commit to providing water on call for fish without an agreement with the Bonneville Power Administration. Martin also said CRITFC assumptions include 500 kaf from non-Treaty storage out of Canada and 760 kaf from Banks Lake near Grand Coulee Dam for summer flow augmentation.
Heinith said the CRITFC plan calls for the Corps to even out the up and down flows from dams caused by hydroelectric operations to meet daily energy needs.
In addition, CRITFC advocates 24-hour spill March 20 to Sept. 15, more than that called for in NOAA Fisheries 2000 biological opinion, which limits spill at most dams to 12 hours and mostly at night, according to Heinith. In addition, the federal plan begins spill April 10 and ends spill Aug. 31. Heinith said fish pass dams 24-hours a day and claims the 12-hour night spill is to save daytime energy generation.
Martin said CRITFC is open to comments on its fisheries plan, suggesting that comments be sent directly to Heinith at CRITFC.
The plan is available on the TMT Internet site at www.nwd-wc.usace.army.mil/tmt/agendas/2003/0319riverops.pdf
Technical Management Team: www.nwd-wc.usace.army.mil/TMT/index.html
Tribes Propose Spring/Summer River Flow/Spill Operations
Columbia Basin Bulletin, March 21, 2003
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