A 2016 agreement is helping protect Colorado River flows downstream of Glenwood Canyon despite ice jams from the Colorado River shutting down the Shoshone Hydropower Plant in the canyon.
Jim Pokrandt, spokesman for the Colorado River District, a tax-funded agency serving counties within the river basin in western Colorado, said the problem at the plant occurred around March 1. Xcel Energy, the plant’s owner, says it won’t be using Colorado River water at the plant until it is repaired.
The plant’s operations are watched closely by the water community because it has one of the oldest water rights on the river in western Colorado — a 1902 right to 1,250 cubic feet of water per second.
That right has limited the ability of Front Range water users with more junior rights to divert Colorado River water. It helps keep water flowing down-river not just to the plant, but further downstream because the plant’s water use is nonconsumptive, benefiting municipal and agricultural water users, recreational river users and the environment.
However, the river district and regional water users have worried about the potential impacts on the river and water users whenever the aging plant is out of service and not calling for water under its senior right, such as when it requires maintenance.
To address that concern, reservoir operators including the river district, Denver Water and the U.S. Bureau of Reclamation agreed in 2016 to cooperate to maintain river flows at levels mimicking Shoshone’s normal operation, with certain exceptions.
Modified reservoir operations to mimic those flows are now in effect, and will remain so until snowmelt runoff causes the river flow to exceed the current outage protocol target of 1,250 cubic feet per second.
Pokrandt said that among the benefits of protecting flows, more water in the river means lower concentrations of total dissolved solids in the river due to dilution, reducing the need for water treatment by municipal water providers that rely on the river.
Kirsten Kurath, an attorney who represents the Grand Valley Water Users Association, a party to the 2016 agreement, said a big benefit of the Shoshone flows is maintaining flows in what’s known as the 15-mile reach of the Colorado River in Mesa County. Efforts to protect endangered fish in the river focus in part on maintaining adequate flows in that stretch of the river, upstream of the Gunnison River confluence.
“The entire state really benefits from keeping in compliance there,” Kurath said.
Pokrandt said the Shoshone flows are important in middle to late summer, helping preserve flows in Glenwood Canyon for rafting operations and other recreational boating.
While Grand Valley irrigators also have senior water rights on the river, Kurath said the Shoshone water smoothes out the river’s flows, making it easier for irrigators to plan and making water diversions more efficient than when flows are lower. “Everybody downstream always benefits as you keep water in the river,” she said.
The Orchard Mesa Irrigation District and Grand Valley Irrigation Co. are among other parties to the 2016 deal. As of late Monday afternoon, Xcel hasn’t yet said how long the power plant may be out of commission. According to the river district, Xcel has said that the COVID-19 outbreak is complicating repair plans.
The utility says service to its electricity customers isn’t affected by the plant’s outage.
The current outage agreement is in effect for 40 years. The river district says it and its West Slope partners are exploring ways to permanently protect the river flows