Dillon Reservoir expected to fill | SummitDaily.com

Dillon Reservoir expected to fill

Summit Daily/Brad OdekirkWith snowpack still on the mountain tops and a relatively cool spring, Denver Water is hoping Dillon Reservoir will fill this summer.

SUMMIT COUNTY – Denver Water forecasts that its Dillon Reservoir will fill by the end of June as long as the weather remains “normal” for this time of year.At worst in a dry spell, the utility’s Summit County facility would top out at about 90 percent shy of its 254,000 acre-feet capacity, Denver Water planner Marc Waage said Wednesday.Chances are the reservoir will fill, which is good news not only for Denver Water’s 1.2 million customers but also for operations of the Frisco Marina.It currently sits at about 80 percent full and the Roberts Tunnel is off, meaning Denver is not diverting water to the Front Range.Waage said the tunnel is not pumping water, thanks to the effects of spring snowfall in the foothills on the eastern side of the Continental Divide that reduces demand on Dillon.Waage predicted the reservoir would remain with three feet of its fill line until Labor Day, which means the Frisco Marina would be fully operable for the summer.

Dillon fills at an elevation of 9,017 feet and the marina needs a 9,011-foot level to operate normally without having to chase water levels down the old highway that surfaces in low water.The Dillon Marina, at the deep eastern end of the reservoir, copes with low water much easier.Another closely watched reservoir statistic is the flow rate from the Dillon Dam into the Lower Blue River. Currently, Denver Water is releasing the minimum 50 cubic feet per second (cfs). Waage said that when Colorado River water rights calls hit during the summer, flows would ramp up between 100 and 300 cfs, which is better for aquatic life but not enough to support river runners.Denver Water manager Chips Barry cautioned river runners not to expect the big Labor Day weekend release of last year that delighted the rafting industry.Ironically, the only chance of a recurrence would be an unwanted dry summer.

Last year, Denver Water timed a release of 3,000 acre-feet for the holiday weekend to help boost Summit’s recreation economy.”Generally speaking, if we have to make a release, we will try to do it consistent with the wishes of people in the local area,” Barry said.Denver’s larger releases are necessary for it to pay back Green Mountain Reservoir water it stored out of priority. In most cases, Denver squares its water account with Green Mountain, located at Heeney, by exchanging water it owns in the Williams Fork and Wolford Mountain reservoirs in nearby Grand County.Last year, those reservoirs were too low and Denver used its more precious Dillon water. Dillon is connected to the Denver system. The Williams Fork and Wolford Mountain reservoirs aren’t, and were built to meet downstream Colorado River water calls while keeping as much Dillon water behind the dam as possible.In other Denver Water news, Barry said the utility is working with Xcel Energy on a new agreement that would have Xcel abate its Shoshone Power Plant call in unusually dry years.The Shoshone plant in Glenwood Canyon is powered by Colorado River water and holds some of the most senior water rights on the river that can call out Denver Water and many others.

Still, Shoshone water calls keep water in the river before and after it passes through the hydro plant’s two turbines. Shoshone water calls help keep other senior Grand Junction area water calls off the river.Green Mountain is one of the reservoirs that keeps Shoshone going when it needs water, much to the benefit of people who like to fish and float the Lower Blue and Colorado rivers.In 2003 and 2004, the Shoshone call was abated in an arrangement that also helped Green Mountain recover from the drought.Western Slope water interests appreciated the short-term deal but would not want to see Denver Water buy out Xcel’s water permanently.Barry said Denver Water is only seeking to maintain the current arrangement.Waage’s and Barry’s predictions came Wednesday during the annual Summit County State of the River meeting organized by the Colorado River Water Conservation District.

During the session, a federal official noted that the Green Mountain Reservoir landslide at Heeney is moving about two inches a year.The Bureau of Reclamation, owners of the reservoir, has put measuring devices into the ground to determine how much the landslide is moving.Reclamation official Malcolm Wilson said the slide is most active by the county’s steel building on Heeney Road that recently served as the Lower Blue firehouse.The landslide is the subject of a contested plan on how to operate Green Mountain in low water years. Reclamation believes that it needs to keep a minimum of 27,000 acre-feet in the 154,000 acre-foot reservoir to hold back the slide.Normally, the reservoir could be drawn down to its dead pool of 7,000 acre-feet, so the River District sued over how Reclamation divvies up the pain of the foregone 20,000 acre-feet.Jim Pokrandt can be reached at (970) 668-3998, ext. 227, or jpokrandt@summitdaily.com.

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