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New NMFS BiOp Explains Why
More Spill Is A Non-Starter

by Bill Rudolph
NW Fishletter, September 19, 2013

Bonneville Dam Spills a substantial portion of the spring freshet. On Sept. 9, NOAA Fisheries released its latest draft hydro BiOp for public comment, to satisfy the concerns of now-retired federal District Judge James Redden, who said it needed more specific actions to improve habitat in the Columbia Basin after 2013.

Judging from early comments by environmental and fishing groups, who have kept the litigation going for more than a decade, their own concerns haven't been satisfied.

Though the latest recipe for dam operations contains more specific habitat actions, as the judge wanted, and maintains most of the spill regime he had ordered, plaintiff environmental and fishing groups are calling for more spill than ever.

The groups have gotten behind a controversial analysis by some state, federal and tribal biologists first reported at a 2011 workshop of the ongoing Comparative Survival Study (CSS). The analysis, published last year in the peer-reviewed journal Transactions of the American Fisheries Society, claims smolt-to-adult returns could improve to recovery levels--around 4 percent--if spill is raised to levels that boosted total dissolved gas levels to 125 percent in dam tailraces. Current state waivers allow tailrace TDG levels up to 120 percent, though sometimes high spring flows can raise it above 130 percent or more.

"A 16-year study indicates that spill is the most effective immediate measure to increase salmon survival across their life-cycle," said Northwest Sportfishing Industry Association Executive Director Liz Hamilton in a statement from pro-spill groups. "The court-ordered spill in place since 2006 has been good for juvenile salmon on their way to the ocean, producing more adult fish back to the river, which has in turn helped salmon businesses and the jobs they support. Based upon extensive analyses, we are convinced that salmon managers need to test higher levels of spill to further increase adult returns. Testing expanded spill is consistent with implementation of adaptive management and should be the centerpiece of any credible salmon plan. Instead, NOAA appears to be ignoring this important information and allowing for less spill during a critical time for Endangered Species Act-listed fish."

NOAA, however, has not ignored this "important" information, but hasn't said much publicly about it until the draft BiOp came out, and even then it isn't easy to find. A discussion about the CSS spill is on page 353 of the 751-page document.

Officials never said a word about it at the Sept. 7 press briefing. NOAA Fisheries' assistant administrator Bruce Suzumoto said simply that survival goals developed back in the original 2008 BiOp (amended twice now by court order) were on track to be met in 2018, when the BiOp ends, so there was no need to increase spill or consider breaching any dams.

BPA customers have been firmly behind the feds' latest salmon plan. "The measures in the Draft BiOp largely carry ahead the good work that the region has done on behalf of fish and wildlife for the last five years," said Bo Downen, policy analyst for the Public Power Council. "The region is at or exceeding nearly all of the goals that were supported five years ago by a broad coalition of states, tribes, and other regional stakeholders. This updated draft continues many of these actions and addresses the deficiencies of the previous BiOp."

In the draft BiOp, NOAA acknowledges that recent CSS reports have hypothesized that "substantially increasing spill levels (which reduce exposure of juveniles to the juvenile bypass systems and turbines) would substantially increase both inriver smolt survival and smolt to adult return rates (ocean survival)."

The BiOp also reports that CSS participants have recommended a large evaluation study. NOAA said it had reviewed these reports, attended workshops and presentations of the CSS model results, and reviewed two critiques of the approach. "In considering this information, NOAA Fisheries finds that several substantial weaknesses in the analysis exist that would need to be resolved prior to further consideration of any operational study of this magnitude."

The feds said the data used to construct the model used a time frame that captured only one year of increased spill. "Since 2006, spill levels have increased at several of the mainstem projects and the efficiency of spill has increased as well with the addition of spillway weirs. (The last spillway weir was installed in 2009)."

NOAA reported that its own unpublished data shows conventional and surface spill pass a larger portion of fish for a fixed spill percentage at lower flows than at higher flows. "Thus, high spill percentages may not be needed to pass the same proportion of fish in lower flow years."

The BiOp also notes the CSS recommendation addressed a hypothesis that juvenile bypass systems at dams cause significant "delayed mortality," based on adult returns. But it says an analysis of the CSS data (Haeseker et al., 2012) by BPA consultant John Skalski (Skalski et al., 2013) found that the spill percentage also correlated with increased adult returns of transported fish--which conflicted with Haeseker's conclusions (since barged fish are not in the river, they cannot benefit from spill).

"The analyses in Haeseker et al. (2012) provide correlative associations only," says the draft BiOp, "and should not be interpreted as demonstrating causation. Spill levels are also correlated with many other inriver conditions or mortality factors, some of which are not discussed in Haeseker et al. (2012). These authors investigated only four covariates in their inriver survival models and seven covariates in their ocean survival models, and the correlations among those covariates were not provided. The Skalski et al. (2013) analysis suggests that spill levels must have correlated with other mortality factors, such as ocean conditions, that were also experienced by transported fish. If the CSS modelers had replaced spill with other correlated factors, it is likely that those factors would have also been associated with similarly increased survival."

NOAA said randomized experiments would be necessary to "adequately assess direct and indirect effects of spill." In their place, the feds suggested a more thorough analysis be conducted, "that includes more potentially influential covariates, an assessment of correlation among variables, and an analysis of influential data points."

The feds also pointed out that the CSS model left out a variable for total dissolved gas, which would leave out 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.

NOAA said it was not dismissing the CSS modeling efforts, but noted that adult returns from 2011, when flows and spill levels were high, produced returns that were below average. It was reported that BPA will soon release John Skalski's review of the CSS spill analysis to both plaintiffs and the public-at-large.

Bill Rudolph
New NMFS BiOp Explains Why More Spill Is A Non-Starter
NW Fishletter, September 19, 2013

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