the film forum library tutorial contact

Snake Spill Starts After Debate over Water Supply, Science by Bill Rudolph NW Fishletter, April 15, 2003

With an improving water supply forecast in their pockets, Columbia Basin fish managers made a formal request for spill to begin at lower Snake River dams to improve juvenile fish survival. The issue was debated at the technical level April 1 and bumped up to policy managers April 3, when it was approved after a lively discussion at the Implementation Team meeting in Portland. The first water started spilling on the evening of April 4.

Just last month, the basin's water supply forecast seemed too low to allow for spill, and managers were prepared to maximize the fish barging policy. When no water is spilled over the dams, more fish are collected in dam bypass systems, where they can be routed to barges that transport them past the dams.

But with last month's heavy snowfall, some areas, particularly in Idaho, were exhibiting nearly normal precipitation for the year. US Army Corps of Engineers' flow modeling, using the mid-month March forecast, had estimated that spring flows would be slightly below the 85 kcfs target that would begin the spill program. A slightly updated version had pegged them at 83 kcfs, which put the spill decision right on the cusp.

Fish managers like Idaho's Sharon Keifer pointed out April 2 that heavy snow in the Clearwater Basin--up to two feet by mid-week--made it likely that the water supply forecast would stay the same or even improve slightly. She also said juvenile fish were showing up early this year. In addition, a large number of wild spring and summer chinook is expected--about 1.7 million fish--as a product of 2001's comparatively large adult returns.

Fish managers had said over 16,000 spring smolts had already been counted at Lower Granite. Last year at this time, only 3,000 young fish had appeared.

Other managers cited a recent review of newer research presented by NOAA Fisheries scientists at the March 19 TMT meeting, which seemed to indicate that, in some years, early migrating chinook survived at higher levels than barged fish. The NMFS analysis also showed that steelhead did not fit this pattern.

NOAA Fisheries spokesman Paul Wagner told IT members that transporting fish early had "little or no benefit in the spring season." Wagner said the analysis showed flows were not a central factor during migration.

But consultant Jim Litchfield, representing the state of Montana, said the data on smolt-to-adult returns "was not convincing" or "something we understand yet." He said only extremely small groups of fish were available for marking early in the season, making for lots of uncertainty about the statistical results.

But NOAA policy manager Jim Ruff said his agency felt comfortable supporting spring spill now, citing the similarity of this year's water supply forecast with that of 2000, when agency data showed most benefits for the earliest inriver migrating chinook.

The Corps of Engineers' Jim Athearn said his agency was willing to do spill now, though he expressed some frustration with the process. He also said his agency didn't view the decision as "precedent-setting."

Athearn said the newest water forecast would give fish and hydro managers time to assess the issue at their next meeting April 9 to see if managers are "still in the same situation we are today."

BPA's Suzanne Cooper said the power agency's financial crisis is not expected to be remedied in the near term. Spill "is a cost to us," she said, "but we also recognize that it's part of our obligation under ESA." She supported the Corps' recommendation to look at the next forecast to ensure that flows will still be estimated at levels high enough to call for the lower Snake spill.

Spill began at Lower Granite Dam at 6 p.m. on April 3, with about 50 kcfs directed over the spillway, about two-thirds of the lower Snake flow. Spill at the next two downriver dams was implemented at two-day intervals.

Some fish transportation has already begun, with smolts being trucked downriver. When smolt numbers become large enough, the Corps will shift to transporting the fish by barge. That was expected to happen in the next few weeks.

"We acknowledge we put the action agencies on the spot," said NOAA Fisheries' Jim Ruff. He agreed with Montana representative Litchfield that a plan should be developed to better integrate "new information" into the planning process. Although there is uncertainty in the data, Ruff said it has led them to believe "the fish are better off in the river right now."