Shoshone hydropower water right ‘relaxed’ in collaborative response to 2-year drought; agreement enables about 20,000 acre feet of additional upstream storage early in the year
By Bob Berwyn
FRISCO — Some key players in the Colorado River Basin have worked together to “relax” a senior water right near Glenwood Springs, enabling more water — about 20,000 acre feet — to be stored in upstream reservoirs.
“We expect to gain about 8,000 acre-feet each in Dillon and Williams Fork Reservoirs as a result of the relaxation,” said Denver Water spokesperson Stacy Chesney.
The 1,250-cfs water right for the Xcel-owned Shoshone hydropower plant dates back to 1902, making it one of the most senior rights on the river.
When Xcel exercises that water right, it affects other water users all the way up the river because it’s administered by the Colorado Division of Water Resources against junior water storage rights in Dillon and Williams Fork Reservoirs, the Colorado River District’s Wolford Mountain Reservoir and the Bureau of Reclamation’s Green Mountain Reservoir.
The agreement “relaxes” the call to 704 cfs when river flows are low, or takes a Shoshone call totally off the river when flows are rising, giving the upstream juniors water rights holders the ability to store water once the spring runoff begins.
Currently, the Colorado River is flowing through Glenwood Canyon at about 825 cfs. (The long-term historical average for this date is about 1,150 cfs).
Two tripping points activate the agreement: when Denver Water forecasts its July 1 reservoir storage to be 80 percent of full or less, and when the Colorado River Basin Forecast Center predicts spring runoff flows at Kremmling in Grand County will be less than or equal to 85 percent of average. Currently, the reservoir forecast is 74 percent full on July 1 and the Kremmling forecast is 60 percent of average.
The winter of 2012 was the fourth worst on record in the Colorado River Basin and 2013 has been tracking just as poorly. The only improvement between the two winters occurred in March 2013 as storms continued to build snowpack. By this time in 2012, runoff was already under way.
The relaxation period is between March 14 and May 20. After late May, more water is needed downstream for boating and irrigation.
Fifteen percent of the net gain is saved for Xcel Energy power plant uses in the Denver Metro Area and 10 percent is delivered to West Slope entities yet to be determined by agreement between Denver Water and the Colorado River District.
“This is a statewide drought, and we all need to work together to manage water resources for the health and safety of our residents, our economic vitality and the environment,” said Jim Lochhead, CEO and manager of Denver Water. “The Colorado River Cooperative Agreement and the Shoshone Outage Protocol are great examples of the partnership between Denver Water and the West Slope to do just that,” Lochhead said.
“Last year, even though the CRCA was not yet in effect, Denver Water released water to the river even though the Shoshone Power Plant was not operating and the call was not on. This year, under the Denver Water-Xcel Energy agreement, the Shoshone call will be relaxed,” he said.
“Relaxing the Shoshone water right in this limited way benefits the West Slope as well,” said Colorado River District General Manager Eric Kuhn. “It might make the difference between having a full supply at Green Mountain Reservoir and not having a full supply. In a year like this every extra drop of water we can store now will help us later.”