GLENWOOD SPRINGS, Colorado - Two back-to-back, drought-plagued winters in Western Colorado have triggered an agreement to "relax" a senior water rights call on the Colorado River at the Shoshone Hydro Plant to allow water providers to store more water this spring, a move that benefits customers of Denver Water and Western Slope water districts and individuals.
The Shoshone Hydro Plant is owned by Xcel Energy and is located in Glenwood Canyon. Its senior 1902 water right of 1,250 cubic feet per second, when called, is administered by the Colorado Division of Water Resources against junior water storage rights upstream that include Denver Water's Dillon and Williams Fork Reservoirs, the Colorado River District's Wolford Mountain Reservoir and the Bureau of Reclamation's Green Mountain Reservoir.
Colorado water law operates under a "first in line, first in time," system. That means those who hold the most senior rights have priority in allocating water. In dry years, senior rights holders can "call" their rights, potentially disrupting water supplies to those who hold more junior rights.
The Shoshone agreement "relaxes" its potential call to 704 cubic feet per second when river flows are low, or takes a Shoshone call totally off the river when flows are rising, which is the current situation. This practice gives the upstream juniors water rights holders the ability to store water once the spring runoff begins in earnest. Currently, the Colorado River is flowing through Glenwood Canyon at about 825 cubic feet per second. The long-term historical average for this date is about 1,150 cubic feet per second.
Two tripping points activate the agreement - when Denver Water forecasts its July 1 reservoir storage to be 80 percent 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.
Denver Water has already enacted its "Stage 2 Drought Restrictions" to limit outdoor water use and enact other conservation measures.
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 of this year, 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, in deference to boating season on the river and irrigation needs in the basin.
As for the water that Denver Water gains by the relaxation, 15 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/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. Last year, even though the (cooperative agreement) 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."
"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."