Snake runoff likely to hit 30,000 cfs

By Jim Stanford on May 20, 2011

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Mike Beus walked into the U.S. Bureau of Reclamation water meeting last night and did two things he never has done here before: He greeted a room full of concerned people, and he did not give a forecast of planned operations of Jackson Lake Dam.

All Beus could do was show graphs of the runoffs from 1996 and 1997, epic high-water years on the Snake River, and say this spring is going to be similar.

Mike Beus

Used to managing water during long periods of drought, Beus came to think of ample runoff as a good thing, he said. “We’re about to witness too much of a good thing,” he said.

Boaters have seen high water on the Snake River the last three years — in the range of 22,000 to 24,000 cubic feet per second in the canyon above Alpine — but this spring is going to take us higher. Although Beus wouldn’t give a prediction, it’s likely the peak runoff in the canyon will reach 30,000 cfs.

The river peaked at 31,600 cfs on June 11, 1996, and 38,600 cfs on June 11, 1997. The 1997 flow represented the highest runoff ever recorded.

Beus said this year’s snowpack is probably more similar to 1996′s. Temperatures and precipitation remain hard to forecast for the next three weeks, and those factors will determine how high the river crests. The later the melting is delayed, the greater the chance of warm weather and a sudden runoff, he said.

Only three times since 1937 has the Snake peaked at more than 30,000 cfs in the canyon; on June 6, 1986, the flow reached 31,300.

The meeting was not all ominous. The bureau has been much more aggressive this spring in releasing water from Jackson Lake Dam for flood control than it was in 1997, and the agency aims to reduce the flow from the dam when tributaries rise in the coming weeks, to relieve pressure on the levees.

Despite those efforts, Jerry Gregg, the bureau’s Snake River area manager, cautioned, “We may or may not have flexibility” when the crest comes.

Although there have been calls in Jackson Hole for the bureau to release more water now — a News&Guide editorial among them — downstream communities such as Blackfoot and Shelley, Idaho, already have experienced flooding, as managers have drawn down Palisades and Jackson Lake reservoirs to make room for the runoff, Beus explained.

After the runoff subsides, boaters and anglers can look forward to a steady release of anywhere from 2,200 to 2,800 cfs from Jackson Lake Dam, based on figures from 1996-1997. That’s good news for scenic rafting guides in Grand Teton National Park, who sweated through August and September last year, scraping gravel bars as the bureau reduced flows to a trickle.

Flooding on the Snake last year near Meadow Road north of Jackson.

Before Beus spoke, Kenny Koebberling, project manager for the U.S. Army Corps of Engineers, gave an overview of the 33 miles of federal levees through Jackson Hole. The levees tend to suffer the most damage at flows of 15,000 to 18,000 cfs at Swinging Bridge (upstream of the canyon), when the current often hits the piles of rip-rap at sharp angles, Koebberling said.

Koebberling sought to reassure county officials and landowners, explaining that personnel are inspecting the levees each day and huge stockpiles of rocks are in place. The Corps spends $1 million per year maintaining the levees, and Teton County chips in $70,000.

Beus, the hirsute operations manager for the bureau’s office in Burley, Idaho, has been coming to Jackson for upwards of 20 years to give his presentation. Last night’s crowd was the largest and most diverse he has faced. In the past, an imposing line of Idaho irrigators would loom over the sparsely filled room. This time, there were a dozen or more rafting and fishing guides joining Teton County Commissioner Hank Phibbs, Wyoming Game and Fish biologists, Snake River Fund advocates and others.

It’s encouraging that people care to stake a claim to management of their river (although those Idaho irrigators still largely call the shots). The bureau pledged to improve its communication with the community and give a heads-up of what’s coming from upstream. There certainly will be plenty.

Peak streamflows in the Snake River Canyon


Posted under Environment, Sports, Weather

3 Comments so far

  1. Boat 1 Retired May 20, 2011 9:26 am

    Sorry to have missed this meeting – that is why the screen name has retired in it – busy taking care of three future raft guides! Looks like there will be full river this year – get ready for under an hour scenic floats and 40 minutes of whitewater fun. Enjoy and be safe out there!

  2. js May 20, 2011 10:46 pm

    This is my analysis, based on observation and experience on the river. It would take extraordinary circumstances for the Snake to rival the 1997 flows this year — heavy precip and a rapid warming to 75 or 80 degrees. Even then, the bureau is ahead of where they were in ’97.

    Throughout this spring, I’ve been guessing the river would peak in the high 20s in the canyon, but I came away from last night’s meeting with the impression the bureau expects it will be bigger.

    What usually happens when flows skyrocket here is the bureau backs itself into a corner, managing for a drought and trying to store every last drop behind the reservoir. When the reservoir fills, the agency has no choice but to match outflow with inflow, and it often underestimates the amount of snow yet to melt. I don’t think they will make the same mistake this spring.

    The News&Guide editorial used alarmist language such as “potentially perilous” and “calamities” in describing high peak flows. I could be wrong, but I don’t recall a catastrophe in either 1996 or 1997. The levees held. There was a lot of flooding below Palisades Reservoir, but I doubt the writer was looking farther downstream than, say, Fish Creek.

    The Army Corps rep spoke of the damage that occurs to levees when flows are considerably lower than historic peaks. He suggested, basically, that higher water doesn’t necessarily correlate to higher danger of levee erosion. When flows reach a certain volume, the energy of the river points more downstream, in a sense.

    Floods are natural. High water is good for the fish, for flushing spawning beds, rejuvenation of cottonwood forests. The river is still runnable. Many of the rapids in the canyon are washed out, but there are big waves in different places. Some companies may have to shut down on various stretches when the flows become too high, but I rarely hear guides cursing too much water.

    It can be an exciting time to float the river, and seeing the Snake at such might is something to behold and appreciate.

    No worries, Boat 1, we had you covered.

  3. joe May 21, 2011 8:15 am

    congrats on getting past news/guide think/speech. could be the beginning of a great community blog and not just collective politics.

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