[3] Compromise Operation Developed For Montana Reservoirs
Regional policymakers have developed a compromise for August operations at Montana's Libby and Hungry Horse reservoirs. The one-year agreement calls for drawing them both down about 10 feet by the end of August, instead of the 20 feet the hydro BiOp calls for to augment flows in the mainstem Columbia River for the outmigration of ESA-listed fish.
The state has been pushing change for the past ten years, which includes a call for steady outflows through the summer to lessen adverse effects on resident fish downstream of the projects. A double spike in flows from BiOp operations was detrimental to resident fish, the state said. Keeping the reservoirs at higher elevations helps boost basic biological productivity along shorelines.
But the latest proposal, officially requested in late May, was a dead duck just a few weeks ago, nixed by the state of Oregon and three of four lower Columbia tribes because it wasn't "flow-neutral." Oregon had actually supported the plan years earlier, when it was added to the region's fish and wildlife program and approved by all four Northwest states.
Last year, an independent science panel that reports to the Northwest Power and Conservation Council thought it was a good idea, too. They said any benefits to downstream migrants were likely too small to be measured.
Montana still offered more water in poor-flow years, and proposed drawing down its reservoirs the full 20 feet in the lowest 20 percent of water years. In other years, it wanted outflows stretched through September to minimize adverse effects to the biological productivity of the reservoirs.
A last-minute compromise over the one-year deal was offered by NOAA Fisheries, whose representative John Palensky said last month his agency would only back Montana if the state could gain "a large measure" of regional agreement for the operation.
Representatives of Oregon and the tribes didn't object to the proposal at a July 18 meeting in Portland. On July 27, the Corps of Engineers began reducing outflows at Libby from 17 kcfs to 14.4 kcfs, and from 5.4 kcfs to 3.0 kcfs at Hungry Horse, expecting to keep them steady through the end of August.
The "flow-neutral" issue was countered by news that there was water in Canada available for flow augmentation right now. The Bonneville Power Administration had made a deal with BC Hydro earlier in the year to hold back a large volume of water to reduce dissolved gas levels in the spring at mainstem Columbia dams. The water is now being released, and is estimated to be boosting flows at McNary by about 14.5 kcfs.
That change will help fish in Montana, said Brian Marotz, fisheries program manager with his state's Department of Fisheries, Wildlife and Parks.
He said optimal flows for Montana fish would be in the 6 kcfs to 9 kcfs range, and the state would look at the situation around Aug. 15, probably to recommend stepping down flows at that time and continuing them into September.
Last year, flows out of Libby averaged about 18 kcfs for the first half August, and stepped down to 12 kcfs by the end of the month, with the elevation down 17 feet.
In 2004, outflows were flatter, averaging about 13 kcfs in August. But that year, the reservoir was filling through July, and only ended August about two feet below its July elevation of 2,450 feet, about 10 feet below full.
But to get the reservoirs down the full 20 feet, as the BiOp calls for, would mean outflows of 20 kcfs at Libby, and 6 kcfs at Hungry Horse, which Montana says would be detrimental to its resident fish.
Marotz said his state is trying to keep the big picture--salmon recovery--in mind, but it questions the ultimate value of its contribution to summer flow augmentation. He said the state had estimated a 20 kcfs flow out of Libby would increase water velocity at McNary Dam on the mainstem Columbia by about 0.6 cm/sec, far below any detectable levels.
High outflows earlier this spring caused widespread gas bubble trauma in fish below Libby Dam. Along with the high spill at Libby, flows were up to 31 kcfs, said Marotz. He said between 80 and 100 percent of the trout below the dam showed signs of gas bubble disease. After fish surveys are completed this fall, managers will have a better idea of how the fish fared, though Marotz told NW Fishletter that it looks like "the bulk of them recovered." Dissolved gas levels ranged up to 131 percent during that period. -B. R.
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NW Fishletter 217, July 18, 2006
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