From the U.S. Fish and Wildlife Service via The Los Alamos Daily Post:
Coordinated releases from a series of Upper Colorado River Basin reservoirs began Saturday, June 3, and are anticipated to continue through this week as part of the Coordinated Reservoirs Operations Program.
The US Bureau of Reclamation, the Colorado River District, Denver Water and Northern Colorado Water Conservancy District as owners and operators of upper Colorado River reservoirs have mutually agreed to modify their operations to benefit the endangered fish of the Upper Colorado River Basin.
The Coordinated Reservoir Operations (CROS) program was established in 1995 as part of the Upper Colorado River Endangered Fish Recovery Program. The purpose of the Coordinated Operations is to enhance spring peak flows in a section of the Colorado River upstream of Grand Junction, Colo. Determined to be critical to the survival of four endangered fish species: the Humpback Chub, Razorback Sucker, Bonytail and the Colorado Pikeminnow. The higher peak flows remove more fine sediment from cobble bars that serve as spawning habitat for the endangered fish. In years with sufficient snowpack, surplus inflows to the reservoirs can be passed downstream to benefit these fish without impacting reservoir yields or future beneficial water uses.
Coordinated Reservoir Operations were most recently conducted in 2016, 2015 and 2010. In 2011 and 2014, wet conditions caused streamflows in certain areas of the basin to approach or exceed levels associated with minor flooding, so CROS was not performed. In 2012 and 2013, reservoirs did not have surplus inflow to contribute due to extremely dry conditions.
Managers of the reservoirs completed a conference call June 2, agreeing to voluntarily run the program this year. Planned reservoir operations as of June 2 are described below. Release and flow amounts are approximate. Most reservoirs will step up releases over the next several days, hold at a constant rate for 3-7 days, and then wind down releases.
Green Mountain Reservoir, operated by the Bureau of Reclamation, will increase releases from 418 cubic feet per second (cfs) to powerplant capacity of around 1400 cfs. Releases from Green Mountain include inflows bypassed by Dillon Reservoir, operated by Denver Water, that will be increased by approximately 100 cfs during CROS.
Denver Water also operates Williams Fork Reservoir, which is releasing 200 cfs. Releases will likely increase to approximately 600 cfs over the coming week to bypass increasing inflows.
Willow Creek Reservoir, operated by the Bureau of Reclamation and Northern Colorado Water Conservancy District, is releasing 90 cfs. Releases will increase this week to roughly 600 cfs by curtailing pumping operations to Granby Reservoir and bypassing those inflows instead.
Wolford Mountain Reservoir, operated by the Colorado River District, is passing inflows of 350 cfs. Outflows will be increased to around 600 cfs for approximately five days.
Ruedi Reservoir, operated by the Bureau of Reclamation, is releasing 182 cfs and will increase releases to approximately 600 cfs over the next few days.
The Colorado Basin River Forecast Center (CBRFC) will incorporate these planned reservoir operations into their streamflow forecasts. Based on weather forecasts and planned reservoir operations, flows in the Colorado River near Cameo (upriver of Palisade, Colo.) are anticipated to be approximately 14,000 – 17,500 cfs, June 7 through June 12, with the highest flows Thursday or Friday June 8 or 9. Flows in the forecasted range are still below defined “bankfull” and flood stages for the area.
More detailed information about forecasted streamflows in the Colorado River basin are available from the CBRFC website at http://www.cbrfc.noaa.gov. A map-based interface allows viewing of hydrographs detailing recent, current and anticipated flows.
For more information, contact Don Anderson, U.S. Fish & Wildlife Service, at 303.236.9883, firstname.lastname@example.org, Michelle Garrison, Colorado Water Conservation Board, at 303.866.3441, ext. 3213, email@example.com or James Bishop, Bureau of Reclamation, at 970.962.4326, firstname.lastname@example.org.
The Upper Colorado River Endangered Fish Recovery Program is a cooperative partnership of local, state and federal agencies, water developers, power customers and environmental groups established in 1988 to recover the endangered fishes while water development proceeds in accordance with federal and state laws and interstate compacts.
From The Summit Daily News (Kevin Fixler):
Through both natural and man-made activities, the area’s waterbodies will ramp back up to seasonal heights this week. The National Oceanic and Atmospheric Administration anticipates the Colorado River and its primary Summit County tributaries will reach their highest 2017 levels this Wednesday, June 7.
The volume-based flow rates, measured as cubic feet per second, on North Tenmile Creek, for example, will rise from about 600 to 900 cfs and the Blue River north of Dillon should grow in the next two days by another couple hundred cfs from its present 600. To offset forthcoming supply, Denver Water, which owns and oversees Dillon Reservoir, stated that it plans to up flows from Dillon Dam into the Lower Blue River from its Monday total of 380 cfs to 600 no later than Tuesday morning, and between 1,400 and 1,800 cfs by the end of the week.
“The snowpack up on the mountain, it’s now warmed up and is starting to come off,” said Jim Pokrandt, spokesman for the Colorado River District, a public policy agency that closely monitors the region’s major waterway. “It’s fast water, but shouldn’t flood anybody out. All streams will be quicker-paced than people are used to, but the flooding is not the danger.”
North of Silverthorne, additional releases at Green Mountain Reservoir also allow the Bureau of Reclamation to increase power plant capacity and generate more electricity. Those levels could reach approaching 1,400 cfs from the current 418.
Estimating that 40 percent of the winter’s snowpack still remains above Dillon, Denver Water is comfortable increasing the flows from Dillon Reservoir into the Lower Blue River that ultimately head to northern Arizona’s Lake Powell. That result is threefold, preventing wasteful overflow of the reservoir, maintaining ideal recreational heights on the lake, as well as fulfilling the demands of Lower Basin states based on senior water rights.
“Our experts are monitoring conditions carefully with the goal of ending runoff season with a full reservoir,” Matt Wittern, Denver Water Summit County liaison, wrote by email. “That way, we’re able to meet our customers’ needs while providing locals and tourists alike with valued summer recreation activities that have a positive impact on the local economy.”
From The Mountain Town News (Allen Best):
Where spring runoff has been something like average—and where it hasn’t
Spring runoff of the Yampa River likely peaked on May 14 this year as it flowed through northwestern Colorado. That makes it an anomaly in the precipitation-dripping mountains of the West.
In most other locations, the peak runoff—the time when the largest volume of water in rivers occurs as winter’s snow melts—more normally occurs in early June after temperatures finally warmed. This year looks to be more or less normal, despite a trend to earlier runoff in many locations during the last several decades.
“The Yampa did have an early runoff, and that was the result of the warm temperatures and below-average snowpack,” said Ashley Nielson, senior hydrologist with the Colorado Basin River Forecast Center in Salt Lake City, when interviewed last week by Mountain Town News. The Yampa, she noted, will probably rise again in the next week or so, if not to the same high mark.
But elsewhere, the show is now, not a month ago. Peak runoff of the Green River was expected this week or next. It originates in the Wind River Range of west-central Wyoming. Unlike the Yampa, that basin still has a significant snowpack. That was also reported to be the case in Jackson Hole, at the headwaters of the Snake River. The snowpack there was 181 percent of average in late May, not a record but “up there,” in the words of one water official cited by the Jackson Hole News&Guide.
Peak runoff in the upper Colorado River at its headwaters along the Continental Divide in Colorado was also expected to occur in early June.
Winter had wild swings: barren until late fall, then torrents of snow in December and January. Temperatures were unseasonably warm in February and almost hot in March. It looked like an early runoff everywhere. Then May turned cold and snowy.
What explains the Yampa’s aberrant behavior? Karl Wetlaufer, a hydrologist with the Natural Resources Conservation Service in Denver, said the peak snowpack in northwestern Colorado arrived about a month earlier than usual. That snowpack around Steamboat Springs occurred on March 12, compared a more typical April 10.
Instead of mid-May for the Yampa, he says that rafters floating through Dinosaur National Monument more often experience the highest water flows of the year in early June.
Flows in the Animas River through Silverton and Durango have had some “pretty wild swings,” Wetlaufer says. The Arkansas River has been slow to get started with runoff.
The Snake River of Wyoming and Idaho has a very different story than the Yampa, with around 200 percent of snowpack this year. The Snake originates in Jackson Hole and picks up water from the Big Wood River, which originates in the Sawtooth Mountains above Ketchum and Sun Valley, before joining the Columbia at the Idaho-Washington border.
“My takeaway is that this year is pretty normal” in terms of timing, says Bruce Anderson, the senior hydrologist at the Northwest River Forecast Center, in Portland, Ore. It was cooler and wetter in spring, but the big story was the amount of precipitation that fell during winter. “We are hugely above normal for precipitation.”
In the Tahoe-Truckee area of California’s Sierra Nevada, the snowpack was among the deeper ones on record after three bad drought years and then a so-so winter in 2015-16. Snowfall this winter was not a record, but it was a record for total precipitation. Being somewhat lower and closer to the coast than Colorado, the Sierra Nevada gets more rain during winter. This year it got a lot of rain.
Colorado, too, had rain on snow, which is not unprecedented. But it happened frequently this winter. The result was telling for travelers on I-70 who crossing Vail Pass.
“In general, there was less snow than you would expect,” says Klaus Wolter, a research scientist at the National Oceanic and Atmospheric Administration in Boulder.
Were those rain on snow storms of this past winter a result of accumulating greenhouse gas emissions? Wolter told Mountain Town News that thinks this is “probably partially climate change.”
Wolter, whose focus is empirical climate research, using statistical methods to solve climate problems, is reluctant to pin climate change on much of what we have seen this year. True, he says, one storm during May left 42 inches of fresh snow in the foothills above Boulder, a storm unprecedented since the 1920s. As extreme as that storm was, proving causality is difficult, he says.
A scientist in Oregon also shared the difficulty of proving causality. John Stevenson of Oregon State University told the Idaho Mountain Express in Ketchum that it’s “really difficult to judge any one year” to be a result of rising global temperatures.
“That’s one of the challenges we run into in the science world where people say, ‘Oh, it’s climate change.’ We’re not at the point where we can take any one random event and say it’s climate change.”
That said, his 2015 study concluded that the point each spring when half of the water year’s streamflow had run off was occurring an average 1.9 days earlier per decade.
But more extreme events are happening with greater frequency, said Mark Davidson, director of conservation initiatives with The Nature Conservancy. He pointed out that the Big Wood River has had two 100-year floods in the last 15 years.
Warm temperatures in the Ketchum and Sun Valley area were 6 to 13 degrees warmer than normal for early May, producing a flood in the Big Wood River that peaked on May 8. It was regarded as the largest in 101 years of recorded history, reports the Idaho Mountain Express.
But more warm weather was producing another surge in early June that threatened to surpass that peak of a month before, the newspaper reported last week.