the film


Ecology and salmon related articles

Council Sends Spill Proposal
to ISAB for Scientific Review

by Bill Rudolph
NW Fishletter, January 9, 2014

Sending more water over spillways, in some ways, may be beneficial for juvenile salmon passage through the hydrosystem corridor. The Northwest Power and Conservation Council has asked the Independent Scientific Advisory Board to review a proposed amendment to the region's Fish & Wildlife program that calls for conducting a 10-year "test" by boosting spring spill at federal dams.

Supporters of the proposal, such as the state of Oregon and the Nez Perce Tribe, point to a controversial analysis by some state, tribal and federal scientists involved in the Comparative Survival Study (CSS) process that concluded fish survival would improve significantly--even to recovery-level return rates of around 4 percent--if spill levels at federal dams in the lower Snake and Columbia were allowed to go up enough for total dissolved gas levels to reach 125 percent in dam tailraces. Current levels are capped at 120 percent.

But other federal agencies have already found significant shortcomings with the CSS analysis. NOAA Fisheries discussed its concerns in its draft hydro BiOp, released in September.

The Fish Passage Center has released a memo slamming the feds' position, and also takes issue with a BPA-funded study that found significant flaws with the CSS spill proposal. The study, by University of Washington statistician John Skalski, suggested the CSS results were based on spurious correlations and it would take decades of data gathering before any robust results could be estimated. The spill proposal calls for a 10-year test with an evaluation after five years.

In a Dec. 16 letter to the science panel, the Council included a series of questions:

    1. Does the experiment include an adequately researched hypothesis?
    2. Is the experiment appropriately designed to test the hypothesis?
    3. Is the proposed duration of the experiment sufficient?
    4. Is it possible to isolate spill as the causative factor for changes in fish survival?

  1. If not, what adjustments will ensure that the proposal is scientifically based?

  2. What are the potential biological risks and/or benefits, particularly focusing on increased total dissolved gas effects on other aquatic species, associated with the proposal?

  3. Is the proposed spill experiment likely to add to our existing knowledge regarding spill, juvenile dam passage survival and adult fish returns (SARs)?
The Council's F&W program includes a provision for some testing.

"The Council supports the development of tests and experiments for the hydrosystem even where some may require temporary departures from operations set forth in current biological opinions." But NOAA Fisheries has the final say in what hydro operations are specified, and it seems unlikely the agency will change its mind.

In the draft BiOp, the feds said the data used to construct the CSS spill model used a timeframe that captured only one year of increased spill. Since then, spill levels have increased at some projects and its efficiency has improved with the addition of spillway weirs.

NOAA also said its own unpublished data showed conventional and surface spill passed a larger portion of fish for a fixed spill percentage at lower flows than at higher flows. And the agency pointed to a recent analysis (Skalski et al) of the CSS study that suggested the correlation between higher spill levels and better adult returns was highly suspect, since the spill percentage also correlated with increased adult returns of transported fish, which didn't benefit from it.

In addition, the feds pointed out that the CSS model left out a variable for total dissolved gas, which would not include higher levels of fish mortality at higher levels of spill. But they also said more years of operation under the current system will add enough data to determine if the CSS hypothesis is right.

Council members were split on the topic when it came to a vote on Dec. 11. Washington's Phil Rockefeller, chair of the Council's Fish and Wildlife Committee, said the ISAB review "is to better inform the Council, not to make a decision on the merits of the proposal."

But Tom Karier, Washington's other Council member, abstained because he felt the spill proposal was "incomplete" when it came to describing the actual experimental protocols, along with a stated hypothesis. However, Karier said he understood that the other members wanted a review and he was not against that. He just thought the science panel could make a more substantive decision if the proposal had been more complete.

In 2009, Washington's Department of Ecology looked at the question of increasing spill and said "the weight of all evidence from available scientific studies clearly points to detrimental effects on aquatic life near the surface when TDG approaches 120 percent."

Idaho's two members voted against sending the spill proposal to the ISAB for review, citing the possibility that if implemented, it could violate the hydro BiOp. Since Idaho has received Fish Accord funding from BPA, the state has promised to support the BiOp as a condition of receiving that funding.

Montana's members supported sending the spill proposal for review, along with Council chair, Oregon member Bill Bradbury. Oregon's other member, Henry Lorenzen, was not in attendance.

The ISAB review is not expected before late February, but the BiOp writers will be weighing in on the topic next week, when the final hydro BiOp goes public. It was slated for release by Jan. 1, but the schedule slipped several weeks due to the federal shutdown in October. It's now scheduled for release Jan.17.

Ritchie Graves, NOAA Fisheries' Federal Columbia River Power System branch chief in Portland, told NW Fishletter last month that his agency will address the FPC's comments on the BiOp and others as part of the final BiOp's rollout.

Graves also pointed out that hydro actions in the BiOp are designed to make sure that dam operations don't jeopardize or impede recovery of ESA-listed stocks, which is different from the type of long-term actions developed for recovery plans. He said that his agency's own research has found that increasing spill would reduce overall survival of listed stocks by reducing the number of fish barged through the hydro system, and the draft BiOp is clear that NOAA wants more fish transported because of demonstrated benefits, especially for steelhead, whose returns have lagged the past two years.

No one has officially ventured an estimate of BPA's cost for implementing a 125-percent TDG spill proposal annually, but it was reported to be in the $100-million to $200-million range. It seems unlikely that such an expensive "experiment" will ever be approved, since it it based mainly on model extrapolations rather than data, and could nearly double the cost of the region's F&W program for 10 years, adding another billion or two to overall fish costs for a decade.

Bill Rudolph
Council Sends Spill Proposal to ISAB for Scientific Review
NW Fishletter, January 9, 2014

See what you can learn

learn more on topics covered in the film
see the video
read the script
learn the songs
discussion forum
salmon animation