Stick to the plan at Libby Dam policy

Inter Lake editorial

Last summer's spill at Libby Dam, and subsequent flooding downstream, was foreseeable and should not have happened.

That's the jarring conclusion that can easily be drawn from a voluminous "After Action Report" put out by the U.S. Army Corps of Engineers, the bureaucracy that operates Libby Dam. Brian Marotz, a fisheries program manager for Montana Fish, Wildlife and Parks, came to a similar conclusion in his own review of dam operations leading up to last June's 19-day spill.

The corps' report cites a variety of reasons why water had to be released over the dam's spillways, causing millions of dollars in flood damage near Bonners Ferry, Idaho, as well as gas bubble trauma to fish below the dam.

But the biggest reason, in our view, is the admission that if the dam had implemented a variable discharge operation strategy as designed and intended, "the spill and flooding at Bonners Ferry could have been avoided."

Properly implemented, the strategy called for increasing releases in mid-April. But the corps maintained minimum 4,000 cubic-feet-per-second flows through mid-May.

Soon after came an unexpected deluge of rain that rapidly filled Lake Koocanusa, forcing the corps to spill water on top of running water through the dam's turbines at maximum capacity.

That's not acceptable, especially considering it was all the way back in 2002 that the corps approved "interim implementation" of the variable discharge policy.

So just when will it be implemented?

And don't forget, the variable discharge policy also is called for in biological opinions for threatened salmon in the lower Columbia River basin and threatened bull trout and sturgeon in the Kootenai River.

We understand that there are conflicting pressures on the corps. Libby Dam water is called on for power generation, for spring sturgeon flows and for late-summer flow augmentation aimed at helping salmon in the lower Columbia, not to mention the ever-present pressure to keep the reservoir as high as possible during summer months for recreation.

But the mistakes of the spring should not be a reason to go backwards. Marotz is rightly concerned that the Army Corps of Engineers may retreat to its old standard flood-control strategy, which deeply drafts the reservoir in the winter, making it difficult in some years to refill.

The state of Montana officially backs variable discharge as the best way to operate the dam, viewing it as the most efficient use of water for power and biological purposes.

We agree, and Marotz says the strategy can be implemented to err on the side of caution, avoiding a forced spill and still coming short of refilling by a few feet.

That is what the Army Corps of Engineers should do in the future. Returning to protective flood-control operations is a waste, especially when the corps' new variable discharge policy has never even been given a proper chance to work as intended.