Shoshone agreement keeps water flowing down Colorado River through Glenwood Canyon

The Shoshone hydropower plant in Glenwood Canyon has been down since at least Feb. 14 and could be down until June, but a 2016 safety-net agreement has kept water flowing down the Colorado River.

The Shoshone Generating Station, owned by Xcel Energy, is the keeper of one of the largest water rights on the main stem of the Colorado River. In February, ice jams on the spillway caused water to flood the plant and damaged equipment inside, according to Xcel media-relations representative Michelle Aguayo.

Xcel said the COVID-19 crisis is complicating repair plans.

“Given the current circumstances, it’s more challenging to get contractors to repair equipment, but even so, we expect to be back in June,” Aguayo said in a prepared statement.

Xcel said service to electric customers will not be impacted by the outage.

The inoperable plant would be a major concern to water users on the Western Slope, except for the 2016 Shoshone Outage Protocol, which mimics conditions as if the plant were still operating and using its full amount of water.

When the plant is operating, a senior water right from 1902 draws 1,250 cubic feet per second of water downstream to meet the plant’s needs. That means that upstream junior water-right holders must leave enough water in the river for Shoshone to receive its full amount. It also means that the 1,250 cfs is available for other downstream users on the Western Slope.

The water used by the Shoshone plant is diverted at a low riverwide dam about 2 miles above the plant near the Hanging Lake exit on Interstate 70. The water is then sent through pipes along the cliffs to penstocks that send it down to the plant, where it spins turbines. All of the water is then released back into the river via a spillway at the top of what’s called the “Shoshone” section of the Colorado River, which is about 5 miles east of Glenwood Springs and is popular with kayakers and rafters.

This water is crucial for endangered fish in the often dry, 15-mile reach near Grand Junction; for boaters and rafters near Glenwood; and for Grand Valley irrigators, who have begun filling their canals for the start of irrigation season, which began Wednesday.

In the past, if the hydropower plant was not operating, the water right tied to it is not being put to beneficial use and cannot be used. The 1,250 cfs could have been lost — either diverted to the Front Range or kept locked in reservoirs. But the Shoshone Outage Protocol took effect March 1 to keep water flowing in the river.

“We are very happy that the outage protocol exists,” said Andy Mueller, general manager of the Colorado River Water Conservation District. “It’s to make sure the water keeps flowing this way. It’s really about the fish as well as bringing the water to the Grand Valley.”

Formalized in 2016, the agreement is signed by many Colorado River water users, water providers and government agencies, including the U.S. Bureau of Reclamation, the Colorado Division of Water Resources, Denver Water, the River District and the Grand Valley Water Users Association.

Between Feb. 14 and March 1, flows were kept up by a winter maintenance outage agreement, according to Victor Lee, an engineer with the Bureau of Reclamation.

Lee said that about 1,400 acre-feet of water from Green Mountain Reservoir in Summit County has been released so far to meet the Shoshone Outage Protocol requirements. He said the protocol will probably be relaxed in the next week or two because spring runoff will begin to naturally boost river flows.

The Shoshone plant and its big water right have long been a concern for the River District, especially since outages have increased in recent years, including a penstock rupture in 2007. Since about 2018, River District officials have been in talks with Xcel about ways to preserve the Shoshone water right for the Western Slope.

“Those efforts are ongoing,” Mueller said. “We still view that as a significant priority for western Colorado.”

Aspen Journalism collaborates with The Aspen Times and other Swift Communications newspapers on coverage of water and river. For more, go to aspenjournalism.org.