New BiOp Stays the Course,
by Bill Rudolph
Before the latest BiOp rolled out Jan. 17, participants in the latest remand process said there would be no big surprises, compared to the draft released last September.
The federal action agencies--BPA, U.S. Army Corps of Engineers and Bureau of Reclamation posted the plan to implement the next BiOp on Jan. 10, and it included answers to questions raised by stakeholders over hydro operations and actions dealing with the other H's and reducing predation from 2014 to 2018, when the current BiOp time frame officially ends.
The Implementation Plan includes several pages on why expanding spill at dams is not in the cards, and tries to explain the difference between BiOp actions, which are designed to avoid jeopardizing ESA-listed stocks; and more general actions to aid overall recovery of evolutionarily significant units, or ESUs.
The IP tackled questions from proponents of added spill, noting that the new BiOp is basically maintaining levels of spill mandated by an earlier court order, but also calls for barging fish earlier in the spring. This change will try to achieve the 50/50 split between barged and in-river migrating spring chinook and steelhead smolts that was called for in the original 2008 BiOp, but hasn't happened since the spill order was implemented in 2006.
The three agencies responded specifically to comments from Save Our Wild Salmon, the state of Oregon and the Nez Perce Tribe, citing a controversial analysis that claims large improvements in smolt-to-adult returns could occur if spill were boosted enough to raise total dissolved gas (TDG) levels in dam tailraces to 125 percent, up from the current 120 percent. The agencies said such a strategy could have "deleterious effects" on both juvenile and adult fish. By diverting smolts away from passage routes with higher survival, creating hydraulic conditions that could cause delays for both juveniles and adults, and increasing TDG levels that may be harmful to fish and other aquatic organisms, the added spill was not considered a viable strategy.
The action agencies said the BiOp is on track to meet juvenile-passage performance standards of 96-percent survival for spring migrants and 93-percent for summer migrants. But by adding more spill, surface collectors would become less efficient and more smolts would pass the dams via conventional spillways, which often generate lower survival rates.
"Furthermore," said the IP's response, "increasing spill at some dams has been shown to alter flow patterns near ladder entrances and delay, or in some cases block, upstream adult passage. Increased levels of spill also increase the potential for adult fish to 'fallback' through the dam's spillway once they have successfully ascended the dam's ladder. Increased fallback of adult fish reduces the survival or conversion rate of fish that fallback, thereby reducing the number of adults that successfully return to spawn."
The IP response also noted that a 2008 literature review of the biological effects of TDG by the Washington Department of Ecology found "that exposure to TDG levels greater than 120 percent harms aquatic organisms consistently enough to omit review of higher TDG concentrations." The action agencies said "spilling to 125 percent TDG in the tailrace, as proposed by the commenters, will further increase the occurrence of gas bubble trauma and adverse impacts on salmonids and other aquatic species. The referenced 2008 literature review also found that fish cannot detect TDG as quickly as they can temperatures and other environmental factors and that at higher TDG levels, fish can die without first showing signs of gas bubble trauma."
The IP's response also noted that the research cited by commenters (CSS 2012 and Haeseker et al. 2012) had problems. They said Haeseker et al. used fish passage and average spill data from 1998 to 2006, "which does not accurately reflect current passage conditions at the dams because the data preceded many configuration actions and operational improvements that were completed and implemented in accordance with the 2008 BiOp."
The IP cited a review of the Haeseker analysis by University of Washington statistician John Skalski, which noted "increased spill also correlates with increased adult returns of transported fish, which receive no benefit from spill. This suggests that spill levels must have correlated with other factors, such as ocean conditions, that were also experienced by transported fish. This correlation conflicts with the notion that simply providing more spill is the key driving factor to increase juvenile survival and boost adult returns, and suggests that ocean conditions and other variables (e.g., harvest, climatic factors) contribute to variations in SARs."
The IP also noted recent NOAA research that has found more than 50 percent of the variation observed in adult salmon returns was correlated to "large scale ocean and atmospheric variables, such as PDO [Pacific Decadal Oscillation] and sea surface temperature, and salmonid growth and feeding."
"While the commenters propose a 10-year test with a comprehensive assessment after five years of testing," said the IP, "Dr. Skalski's analysis pointed out that a systemwide spill test could take 28 years or more to discern a measurable difference (80-percent chance of detecting a 10-percent change) in SARs between the current BiOp recommended spill levels and commenter-proposed spill levels."
Coincidently, the new BiOp was released on Jan. 17, the same day that the region's Independent Scientific Advisory Board reviewed the 125-percent TDG spring spill "experiment" under the aegis of the Northwest Power and Conservation Council. The Council voted last month to have the ISAB review the proposal as a potential amendment offered by Oregon and others to the region's fish and wildlife plan, which is under revision.
Unofficial estimates of the annual cost of such an action are in the $110-million range.
Responding to Northwest Requirements Utilities' comment that higher levels of spill may already be hindering adults returns, the IP responders agreed somewhat. "Although spill levels over the target fish passage spill levels may be contributing to adult conversion rates falling below the BiOp performance standards, other factors are also likely contributing to the shortfall. Pinniped predation and harvest are obvious factors that may contribute to the shortfall in the lower Columbia River. To further investigate the shortfalls, the Corps added additional PIT tag monitoring at The Dalles Dam in 2013 to help isolate where adults are being lost. Once the area of loss is determined, the mechanism for loss may be more readily identified and remedied."
The IP also defended the "expert panels," convened in 2012, that looked at each habitat action in depth and estimated juvenile fish-survival improvements from both completed and future actions to restore habitat in tributaries and the estuary, a murky process that usually involves "best professional judgment."
The panels consisted of biologists and tribal members familiar with each subbasin under review. More habitat actions have been added to boost numbers of six priority populations, where the panels had judged that current restoration work was inadequate to reach survival-improvement goals developed in the earlier BiOp.
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