It’s rare when Denver and the Western Slope agree on water issues, but communities on both sides of the Continental Divide will benefit from a deal the Denver Water Board recently struck with Xcel Energy.
On the Colorado River, upstream from Glenwood Springs, Xcel operates the Shoshone hydropower plant, which has water rights dating from 1902 – making them some of the oldest legal claims on the river. The only more senior rights to the river belong to Grand Valley farmers. So during dry spells, the Shoshone plant gets dibs on the river’s use, as long as Xcel lets enough water flow through to satisfy the Grand Valley claims. However, that normal allocation caused tensions during the 2002-03 drought.
Like many Front Range cities, Denver gets much of its water from the Western Slope, a longstanding point of tension between the regions. Denver Water also supplies about half the metro area’s suburbs. One of the system’s most important storage units is Dillon Reservoir, which dams the Blue River, a tributary to the Colorado. But Denver’s water rights on the Blue (and by extension, the Colorado) date only from 1936.
So when Xcel runs its Shoshone power plant, Denver has to forgo storing some water at Dillon. That was true even four years ago, during the worst drought Colorado has had in three centuries.
Although Xcel and Denver worked out a temporary arrangement, the experience rattled Denver and some Western Slope communities that also were forced to let water just flow past their nearly empty reservoirs.
So when Xcel wanted to renew its utility franchise with Denver for another 20 years, the city said it wanted a Shoshone water agreement as part of the deal. And Denver bargained for benefits for both the Front Range and Western Slope.
The new agreement defines drought conditions in specific terms, such as reservoir levels falling below 80 percent of capacity. In those conditions (so rare they’ve occurred only three times in 50 years), Xcel will let Denver keep extra spring runoff in its reservoirs between March 15 and May 20. That cut-off date means water will flow through the power plant and into popular river-running segments on the Colorado before the height of the tourist season, thereby sustaining Garfield County’s economy.
Western Slope communities got basically the same deal: During droughts, they’ll be able to store early spring snowmelt at Green Mountain, Ruedi, Wolford and Clinton reservoirs, thus protecting municipal supplies in Grand and Summit counties.
Under the pact, when the cities are trying to store extra water, Xcel will shut down the smaller of Shoshone’s two turbines. The amount of water the company surrenders, 30,000 acre-feet, is a fraction of the 850,000 acre-feet the power plant uses annually. An acre-foot is enough water to serve two families of four for a year.
In return, Xcel renewed its 20-year franchise, contingent on voter approval. Denver also will provide additional water for Xcel’s metro-area Cherokee power station.
It’s hard to find any losers in this deal.
