Kootenai flooding could have been avoided

By JIM MANN

Reports say variable discharge would have worked

The Daily Inter Lake

The U.S. Army Corps of Engineers admits in a recent report that spilling and flooding last spring could have been avoided had Libby Dam operators followed a variable discharge protocol rather than trying to refill Lake Koocanusa.

The "After Action Report" makes it clear that the Corps was striving to refill the reservoir to provide later releases for sturgeon and salmon. That, combined with optimistic inflow modeling and an unexpected deluge of rain in June, led to 19 days of spills from Libby Dam and flooding on the Kootenai River at Bonners Ferry, Idaho.

Brian Marotz, fisheries project manager for Montana Fish, Wildlife and Parks, also has evaluated what happened and came to a similar conclusion.

"The Corps said that if VARQ (variable discharge) had been implemented as designed, the spill and flooding at Bonners Ferry could have been avoided," Marotz said. "It was uplifting that their after-action report came to that conclusion because that is the conclusion that we came to."

Oddly, the report states that "the Corps has been operating Libby under VARQ Flood Control" since December 2002, but then it goes on to describe in detail how variable discharge guidance was not followed last spring.

"On April 19, VARQ Refill guidance was issued recommending the release of 16,400 cubic feet per second," it states. "However, to meet multiple objectives, a decision was made to continue releasing 4,000 cfs rather than those recommended in the April VARQ Refill Guidance."

The 4,000 cfs minimum flows were maintained until mid-May. By then, record high temperatures in the Kootenai Basin resulted in a rapid runoff, followed by record rainfall of 266 percent of normal in June.

To keep up with inflows and a rapidly rising reservoir, the Corps started releasing water over the dam's spillways on June 8, and continued spilling water until June 27.

The spill resulted in flooding at Bonners Ferry, causing an estimated $10 million in crop and agricultural land damage. The Corps spent $1.4 million on emergency response activities, including the delivery of some 80,000 sandbags to the community.

The spill also caused cumulative gas bubble trauma to native fish below the dam, including threatened bull trout. According to Marotz, half of the fish in the river had symptoms of bubbles on their eyes and fins, and by the 11th day of spill, every bull trout and about 80 to 90 percent of the mountain whitefish and rainbow and cutthroat trout had symptoms.

Marotz said "very few" dead fish were observed in sampling the river during the spill, but there may have been long-term impacts. Gas-bubble tissue damage could have exposed fish to secondary infections or there could be other unknown effects.

"We won't be able to say what it did to the fish population until we repeat the sampling at the same time next year," Marotz said. "If there is high mortality in one age group, that will show up."

Nola Lyde, a spokeswoman for the Corps, said the report is pointing the agency to pursue a variety of changes, such as reviewing forecasting methods, looking at improved procedures and communications with state and local agencies and the public.

And the Corps is now reviewing the manner in which Libby Dam should be operated - using variable discharge or reverting to a more conservative, standard flood-control operation that involves deeply drafting the reservoir before spring.

"I think the bottom line is that the protection of life and property is the number one priority," Lyde said.

One reason flood-control operations are being considered, Lyde said, is that variable discharge refill guidance in the years 2002 through 2005 would have resulted in the reservoir coming up short of full pool.

In other words, why use variable discharge if it does not meet one of the objectives it's intended to meet. There's a higher probability of not refilling with a standard flood-control operation, but at least the risk of spilling and flooding is reduced.

Marotz said he was disturbed to hear Corps officials say as much at a recent meeting in Bonners Ferry. Marotz said the Corps has yet to strictly implement variable discharge, an operations strategy that he believes makes the most efficient use of water by adjusting refill from year-to-year based on projected inflows and other conditions.

"If they had implemented VARQ correctly this would not have happened," said Marotz, referring to the spill and flooding. "VARQ is hugely important for balancing power production, flood control and fisheries concerns for downstream salmon and our fish in Montana.

"I just don't want to see them throw the baby out with the bathwater," he added. "I'm concerned that people are trying to shed doubt on a perfectly good operations strategy that wasn't correctly implemented."

Corps officials have invited Marotz to share his comments with the agency's technical staff.

"We've done some calculations that will be very useful to the Corps," said Marotz, who acknowledges that Libby Dam is a difficult project to operate in the spring because of the competing demands for water use.

Variable discharge can be applied in a fashion that "errs on the side of flood control, even if it means missing refill by five feet or less," Marotz said. "I want to work on refining the decision space so that you avoid fill-and-spill and avoid missing refill by too much."

Reporter Jim Mann may be reached at 758-4407 or by e-mail at jmann@dailyinterlake.com