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SCT Mulls Accelerated Spillway Weir Implementation

by Barry Espenson
Columbia Basin Bulletin - October 25, 2002

The Regional Forum's System Configuration Team eyed warily options for accelerating installation of expensive fish passage devices that are thought to have the potential to cut the cost of improving survival of salmon and steelhead migrating through federal hydrosystem projects.

The SCT on Tuesday considered three options for improving the cost efficiency of fish passage -- the installation of "removable spillway weirs" and "behavioral guidance systems" at the Lower Snake River's Ice Harbor and Lower Monumental dams and of a BGS in the forebay at The Dalles Dam.

The BGS forebay guidance structures are intended to steer migrating juvenile fish away from the powerhouse turbines and toward the spillbays or RSWs. It is believed that the RSW's will pass a larger number of fish per volume of water than traditional spill. Theoretically that would allow less water to be spilled for fish passage, which in turn would reduce the amount of total dissolved gas produced in the spillbay tailwater and leave more water available for power generation.

The caution by fish managers on the SCT stems from the fact that the RSW technology is relatively untested, and that the costly installation would push other needed projects off the implementation list. Research and capital fish passage improvements at the Columbia/Snake River federal hydro projects are funded with money appropriated by Congress. The money, about $80 million annually in recent years, is reimbursed to the U.S. Treasury by the Bonneville Power Administration.

Such fish costs are paid as mitigation for the impacts to wildlife from the construction and operation of the federal hydrosystem. BPA, as a federal agency, also has funding responsibilities for improvements deemed necessary to avoid jeopardizing the survival of 12 Columbia River basin salmon and steelhead stocks that are listed under the Endangered Species Act. Specific spill regimes are called for in the National Marine Fisheries Service's 2000 biological opinion on hydrosystem operations. The Regional Forum, of which SCT is a part, works to ensure BiOp prescriptions are implemented with the goal of meeting survival improvement performance standards established in the BiOp.

According to BPA's Kim Fodrea, the federal action agencies had for the past 1 months been engaged in discussions with NMFS and the U.S. Fish and Wildlife Service to come up with more cost effective means of achieving those performance standards. The action agencies are BPA, which markets energy produced in the system, and the Army Corps of Engineers and Bureau of Reclamation, who operate the dams. BPA is amidst a financial crisis and predicts that it will incur as much as a $1.2 billion loss over the next four years unless it raises rates and/or cuts costs.

And while the project costs are high -- an estimated $45.8 million each at Ice Harbor and Lower Monumental and $42 million at The Dalles -- they are expected to bring savings in terms of reduced volumes of spill with that unspilled water used instead to turn turbine power generators.

A draft document produced for discussion purposes sets the operational cost savings for the Ice Harbor alternative at $14 million per year (range -- $4 million to $23 million). That's based on a 60-year average. The estimated operational cost savings for The Dalles physical guidance device, based on a 60-year-average, is $10 million annually (range $7 to $12 million). The Lower Monumental project's annual savings are projected at $6 million ($0 to $16 million). The savings are, for the most part, revenues that would be foregone if the additional water is spilled.

"Is BPA ready to direct fund this?" Rod Woodin of the Washington Department of Fish and Wildlife asked.

No, Fodrea said. If it is decided to go ahead with the accelerated schedule for any of the projects, the BPA would seek funding through the Columbia River Fish Mitigation Program that is funded by the congressional appropriation.

"There's no way we're going to fit this under the CRFMP," Woodin said.

The Columbia River Inter-Tribal Fish Commission's Tom Lorz questioned the strategy, saying that the two BGS-RWS configurations would be "survival neutral" at best as compared to BiOp spill. He said only The Dalles proposal was likely to produce survival increases over current operations. Funding the accelerated projects might force out other projects that could improve survival, Lorz said.

Though still largely unproven, the RSWs could have the potential to better BiOp spill survival, said Mike Mason of the Corps' Walla Walla District.

The first biological testing of the RSW concept was conducted this past spring and the data derived, though promising, is preliminary and limited. Further testing is being planned for next spring. The draft alternatives being considered stress that any benefits of installing the RSWs is "speculative in nature." The documents also advise the technology developed for Lower Granite may not be directly transferable to other dams.

Fodrea stressed that the idea of fast-tracking the projects is not a recommendation from BPA or any of the other federal agencies. Rather they are options for the region to consider in the coming two months. To meet timelines that enable BPA to wring cost efficiencies from the projects for rate case purposes, work would have to begin on two of the projects yet this year.

An estimated $750,000 would be needed during fiscal year 2003 to do preliminary design work and hydraulic modeling on the Ice Harbor BGS and RSW projects. The schedule shoots for construction/installation in March 2006.

Launching The Dalles project would cost about $2.5 million during 2003 for a forebay study and modeling. It is believed the guidance structure would allow a reduction in spill while maintaining high fish passage efficiency -- the number of fish that pass the structure via non-turbine routes.

Studies have shown that both spill survival and tailrace egress are improved with lesser levels of spill at The Dalles. Spillway survival has been calculated to be about 94 percent at 40 percent spill, but 96 percent at 30 percent spill. But studies also indicate that the FPE for spring migrants is 92 percent and 81 percent for summer migrants at 40 percent spill. Those FPEs drop to 76 percent and 64 percent in spring and summer, respectively, at 30 percent spill and seem to be drastically lower at 20 percent spill. The BiOp calls for 40 percent spill.

Corps officials at Tuesday's meeting acknowledged that the accelerated schedule for The Dalles project would be hard to achieve, and the $2.5 million expenditure would be hard to squeeze into an as-yet undermined budget. The SCT has already prioritized a list of project that would cost $87 million to implement in fiscal year 2003. That is at the upper end of the range being discussed in Congress.

"Why shoehorn it in" in 2003 if completion by 2006, as would be required to help BPA generate more revenue in the 2002-2006 rate period, is questionable anyway, said NMFS' Bill Hevlin, SCT chairman.

The Ice Harbor proposal "has the most potential" for accelerated development, said the Corps' Kevin Crum. But even it has many question marks.

Spill survival under BiOp prescriptions produced 98 percent spillway survival in 2000 but unpublished results from this year showed survival much lower. An additional year of testing could help resolve that contradiction. A 98 percent survival rate would hard, if not impossible, to beat. And BiOp spill conditions at the dam pass nearly 90 percent of the fish -- more than the RSW capability.

"However, if higher spillway flows contribute to lower spillway survival, as will be researched in the spring of 2003, RSW and BGS may provide a survival benefit higher than existing BiOp spill," according to the draft alternative description.

SCT member also noted that another year of testing of the RSW technology at Lower Granite would also be helpful.

"We're taking some risk by going on parallel tracks," the Corps' John Kranda said of launching the preliminary Ice Harbor work this year, before that additional year of testing is done.

"There's an off ramp if Lower Granite studies don't show us what we expect them to show," Kranda said.

Mason said that the Executive Committee -- the policy making level of the Regional Forum -- had advised that the steps be taken to assure that the alternatives can be implemented by the end of 2006 if it is decided that go ahead with the work. That means gambling with the expenditure for the startup work at Ice Harbor.


Barry Espenson
SCT Mulls Accelerated Spillway Weir Implementation
Columbia Basin Bulletin, October 25, 2002

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