BuRec plans robust flow on Snake

By Jim Stanford on May 17, 2013

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Reed Finlay surveys the Snake this week with the Barker-Ewing crew in Grand Teton park. Higher flows should allow for more braided channels.

Heading into a second year of drought with reservoirs already drawn down and snow melting fast, the U.S. Bureau of Reclamation is planning to release nearly twice as much water as usual in the Snake River this summer.

Barring prolonged wet weather, water managers will release 4,000 cubic feet per second from Jackson Lake Dam through September.

Mike Beus

The agency projects to draw down Jackson Lake reservoir to about 18 percent of capacity. At best, the bureau will fill Palisades Reservoir to about 50 percent of capacity before draining it nearly dry to meet irrigation needs in Idaho.

Mike Beus, BuRec operations manager, presented his projections along with weather forecasts at the agency’s annual water meeting last night in Jackson. A crowd of anglers, irrigators, farmers and rafting guides attended.

Beus painted a stark picture of less water available for storage in the basin, temperatures skyrocketing to 90 degrees in Boise last week and snow melting in the high country above Jackson Lake at a rate of 2 inches per day. While this weekend’s cool, wet weather offers some relief, temperatures were 10 degrees above average for the first half of May, he said.

“The normals are changing,” he said.

The projected flows on the Snake are excellent for scenic and whitewater rafting but not optimal for fishing. With nearly twice as much water, native cutthroat trout will be harder to catch. But the steady flow is preferable to a sudden and dramatic rise late in the season to meet irrigation demands, as happened in 2002, one of the years most closely matching current conditions.

The long-range outlook calls for a higher chance of a warmer, drier summer.

Water management in the Snake basin is highly complex, with each decision affecting the operation of dams downstream. Managers must balance the needs of endangered Pacific salmon, sovereign Indian tribes, irrigators, farmers, cutthroat trout, anglers, outfitters, rafters and motor boaters, among others.

As is his custom, Beus presented a slew of graphs with lines as intricate and interwoven as the strands of his long, grey beard. Looking at runoff and storage from years past, he saw similarities to 2007, 2003, 2002, 1991 and 1989 — all relatively dry.

The peak flow on the Snake through Jackson Hole is likely to occur within the next week, he said. The release at Jackson Lake Dam hit 4,000 cfs today, and the river was running 8,000 cfs at Moose. The flow in the canyon likely will exceed 14,000 cfs this evening.

The early runoff has forced the contractor building the new pathway bridge over the Snake to cease work in the river. Crews had been struggling to install the second piling; instead they will begin building the east abutment.

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12 Comments so far

  1. Brad May 20, 2013 9:42 am

    Whatever else this means, navigation on Jackson Lake will become iffy. At the rates revealed here, boats in Colter Bay will have to leave by August 15.

  2. Jim Stanford May 20, 2013 1:46 pm

    Good point. I don’t do much boating on the lake, so I couldn’t speak to the impact. But with the reservoir being drawn down so low, ramps will be out of the water.

    Also, a reader asked over the weekend about “twice as much water as usual.” I meant in terms of stream flow, not total water drained from the reservoir. It’s hard to generalize about BuRec operations, but in years of average runoff they often aim for a summertime release of about 2,000 cfs into the Snake from Jackson Lake Dam. The bureau’s overriding goal is to store as much water as possible in Jackson Lake in case of continued drought the following year. What many people do not realize is that during dry years, the river flow actually can be higher (especially in late July and August) because of the need to move stored water to Idaho. In some wet years, the release from Jackson Lake is low because the bureau is trying to refill the reservoir.

  3. Jorel May 21, 2013 9:44 pm

    When you drive through idaho, or most any US farmland, they’ve got sprinklers going full blast in the hottest part of the day. I’m clearly not an irrigation pro, but is this the most effective/efficient way to water crops, especially tubers underground? It must be, why else would any farmer do it this way, but it appears as if you’d lose a lot of water to evaporation.

  4. Jim Stanford May 29, 2013 10:12 am

    Holding true to form, no sooner did the BuRec announce its operations plan than it began changing it. Today the release from Jackson Lake Dam is down to 3,000 cfs. This is in keeping with the agency’s mission of storing as much water high in the basin as possible. The recent cool, wet weather has made this possible. But the long-range outlooks continue to forecast drought: http://www.mountainweather.com/index.php?page=longrangeoutlooks
    Don’t be surprised when BuRec goes back to 4,000 cfs.

  5. joe May 29, 2013 4:27 pm

    sounds like the BuRec knows the difference between weather and climate politics

  6. Brad May 30, 2013 9:51 am

    I agree, Joe, seems that way. Which is why Jim is correct as well. They are responding to a specific prolonged weather condition which will change and the releases will be back up to 4,000 cfs shortly and remain there. Good times for whitewater.

  7. Brad June 18, 2013 3:39 pm

    I see by the Bureau of Reclamation website that the Jackson lake Dam releases are now back up 4500 cfs, as predicted after a brief cold and rainy spell. American Falls and Palisades reserviors have had steady releases for some time but levels are falling. Have fun, whitewater peeps, as the recharging of Palisades is on till further notice.

  8. Jim Stanford July 2, 2013 11:06 am

    Here’s an update from the Bureau of Reclamation last week. There will be plenty of water in the Snake for floating all summer. Already the water temperature is above 60 degrees, even taken in GTNP in the morning. Could be bathwater by the time Jackson Lake gets lower in August.

    Jackson Lake is currently at 91% capacity with releases at just over 5,000 cfs from the dam. Due to water demands, releases will continue at 5,000 cfs through July. If demand allows, they expect to reduce releases 500 cfs every 15 days starting August 1.

    Spring operations attempted to follow the natural inflow to Jackson Lake by reducing releases in mid-May to match inflow. A second peak in inflow was expected and would have allowed Jackson Lake to fill. Due to unexpected weather conditions, the anticipated second peak in inflow didn’t come, resulting in the current situation.

    Storage in Jackson Lake is anticipated to be 125,000 acre feet at the end of the season (end of Sept). Colter Bay boat ramps should be functional until early August. Boat ramps at Signal and Leeks should be functional throughout the season based on current projected operations.

  9. Brad July 2, 2013 12:43 pm

    Too optimistic, in my view. Jackson Lake at 87% today. A this rate, most of the boats will be out of Colter by July 31. And, given that American Falls has increased its releases this week, Palisades will follow suit sooner rather than later. I bet they don’t cut back Jackson Lake at all until late September.

    Question: all things being equal (no climate change factors), what are the physics behind increased dam releases resulting in higher temps on the Snake?

  10. Jim Stanford July 2, 2013 12:59 pm

    I agree. Doubtful irrigation demand will taper off.

    I’m not a physicist, but as the reservoir shrinks, it’s easier for the sun to heat the water. A shallow lake gets warmer faster. Think String Lake vs. Jenny.

    Water is released from the bottom of the reservoir, so it’s usually cold. But with the strikingly hot weather of late, the river is heating up. I was surprised to find the temperature so warm already. By late afternoon, it’s comfortable for swimming, especially farther downstream. Game and Fish asked for a voluntary ban on afternoon fishing in August 2007, when the river was warmer than 70 degrees. Trout prefer cold water.

  11. Brad July 3, 2013 5:09 pm

    Based on your response I would think it’s just the river in shallower places getting warmer. Jackson Lake, where it hits the dam is pretty cold that deep. I was just curious if more water running faster in the river could account for the higher temps. Has the river been as warm as 70 deg. since 2007?

  12. Jim Stanford July 18, 2013 8:55 am

    Here’s yesterday’s update from BuRec:

    Releases from the dam are currently just below 5,000 cfs. No change in outflow is anticipated before Aug. 1.

    Jackson Lake is currently at 75 percent capacity and falling 0.3 ft per day. Colter Bay boat ramp should be functional until about Aug. 1. Signal and Leeks boat ramps should be functional through September. Due to recent increases in inflow to Jackson Lake, projected storage at the end of the season is now 150,000 acre ft.

    BuRec will update operations again 9 a.m. July 31. They are currently anticipating flow reductions after Aug. 1 by 500 cfs every 2 weeks.

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