[env-trinity] Times-Standard: Study lists Trinity Dam flows for fish as high priority

[Tom Stokely]

http://www.times-standard.com/popular/ci_26802204/study-lists-trinity-dam-flows-fish-high-priority?source=most_viewed


 


Study lists Trinity Dam flows for fish as high priority
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Research creates baseline list for state to begin fish-health mitigation
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By Will Houston and Juniper Rose
whouston at times-standard.comjrose@times-standard.com
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POSTED:   10/25/2014 11:09:51 PM PDT

A study released this month by the UC Davis Center for Watershed Sciences listed Trinity Reservoir as one of 181 California dams whose current outflows could negatively affect native fish species if unchanged.
With the demand for reservoir water increasing as the statewide drought persists into its third year, study co-author Ted Grantham — a postdoctoral researcher at UC Davis during the study and a research biologist for the United States Geological Survey — said it is important to look at how it may affect other species.
"We have thousands of dams throughout the state, and obviously during this drought year we are really concerned about how the aquatic environment in general is going to be affected by the drought," he said. "There is a balancing act between meeting demands of agriculture and urban areas and the environment. We want to make sure the decisions made don't have irreversible affects on the environment."
The study, published in the scientific journal BioScience on Oct. 15, looked at 753 of California's nearly 1,400 dams and assessed which downstream flows have been modified in a way that is harmful to fish, and which of those areas are habitats for threatened or endangered fish. Dams were chosen and screened based on their reservoir capacity, their alteration of natural downstream flows and impact on nearby biological communities. About 25 percent — or 181 dams — were identified in the study as having flows that may be too low to sustain healthy fish populations — the largest capacity dam being Trinity Dam.

While the study does address a topical issue, Yurok Tribal Fisheries Program Director Dave Hillemeier said the study's screening method left out a number of other negative factors caused by flow alterations that would have increased the number and types of dams that would have been listed. If these were considered, he said three hydropower dams — the Iron Gate and Copco 1 and 2 dams — on the Klamath River proposed for removal by the Klamath Basin Hydroelectric Restoration Agreement would have made the list.
"I think the analysis was driven by reservoir size and flow alteration, and I think that if other ecological impacts of dams that would have been considered — impacts such as downstream water quality, toxic algae, lack of access to historical fish habitat, the role of dams in fish disease — other factors such as those, that the Klamath River dams would have floated to the top of the list," he said. "To me, that was real shortfall of the study."
The removal of these dams, along with the J.C. Boyle dam in Oregon, is part of three agreements currently before Congress that are proposed to give more water certainty to irrigators, improve and protect riparian areas and economic development for the Klamath Tribes and its members and authorize other agreements that would settle water rights disputes using collaborative solutions to water management in the Upper Klamath River Basin.
The study acknowledged why it limited its assessment.
"We reiterate that the framework is a screening-level tool that shows where environmental flows likely warrant attention, but decisions over where to invest resources in environmental flows for ecosystem restoration need to be supplemented by knowledge of local ecological, social, and economic conditions," the study states.
Grantham said the initial study began about three years ago after a few lawsuits invoked California Fish and Wildlife Code 5937, a state law that requires any dam operator to release enough water downstream to keep fish in good health, regardless its purpose, and take the needs of downstream fish into account.
"This law historically has been ignored and has not really played a role in how dams have been managed," he said. "There have been cases where this law was employed in a few lawsuits, but in theory it could be much more broadly enforced. ... I would hope that the state and others would be prompted to take a closer look and evaluate whether these dams are in compliance with the state law."
The study also acknowledged that some dam operators do monitor these biological impacts, but said state agencies have yet to undertake the "daunting task" in identifying which dams are in compliance.
Supporting a population of threatened coho salmon, the Trinity River is fed by the Trinity Reservoir and has already been highly sensitive to reduced flows, with the federal government releasing a fish-kill preventive release and an emergency release within the last three months.
Hillemeier said the Yurok Tribe initially requested that the Trinity Dam be removed, but after that request was not heeded, it began to push for the Trinity River Restoration Program created in 2000. He said state funding for the program, which seeks to restore the watershed on a number of fronts such as gravel replenishment, flow management and channel rehabilitation, has not been consistent.
If fully implemented and funded, Hillemeier said the program "would go a long way to restoring that ecosystem," which he said has undergone several changes due to the deviation from its natural flows.
Will Houston can be reached at 707-441-0504.
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