Coordinated Releases for Endangered Fish Begin

LAKEWOOD, Colo. – 2019 has been a wet year for Colorado. Increased snowpack and the resulting snowmelt runoff into the Upper Colorado River has ensured most river reservoirs are at a surplus. As a result, today participants in the Coordinated Reservoirs Operations (CROS) program will initiate a series of water releases to the Colorado River upstream of Grand Junction, Colorado. This portion of the river is critical to the survival of four endangered fish including the humpback chub, razorback sucker, bonytail chub, and the Colorado pikeminnow.

These voluntary releases will occur after the Colorado River has reached peak flow and will support flows at lower levels that can still improve habitat for the four endangered fish. In years with sufficient snowpack, surplus water can be passed downstream of the reservoirs to benefit endangered fish without impacting reservoir yields or future water uses. This increased flow helps to remove fine sediment from the cobble bars that serve as spawning habitat for the fish and provide other habitat enhancement benefits.

Planned reservoir operations and releases begin today and are anticipated to continue through the coming week. Most reservoirs will step up releases over the next several days, hold those releases at a constant rate for three to seven days, and then wind down. Release and flow amounts are approximate:

  • Green Mountain Reservoir, operated by the Bureau of Reclamation, will increase releases from approximately 800 cubic feet per second (cfs) to power plant capacity of around 1400 cfs. Releases from
  • Green Mountain include inflows bypassed by Dillon Reservoir, operated by Denver Water, which will be increased by several hundred cfs.
  • Williams Fork Reservoir, operated by Denver Water, is currently releasing around 350 cfs. Releases there will likely increase to approximately 700 cfs over the coming week.
  • Ruedi Reservoir, operated by the Bureau of Reclamation, is releasing about 355 cfs and will begin increasing releases Saturday, ramping up to approximately 650 cfs over the next few days.
  • Homestake Reservoir, operated by Colorado Springs Utilities, may also participate in these releases next week after peak flows on the Eagle River recede.
  • Windy Gap Reservoir and Pump Station, operated by Northern Colorado Water Conservancy District, will delay pumping water to Granby Reservoir during the CROS operations.

Based on weather forecasts and planned reservoir operations, flows in Cameo upriver of Grand Junction are anticipated to peak near 21,000 cfs late Friday, June 14 through early Sunday, June 16. The CROS releases are expected to reach Cameo on Monday, June 17 and slow the decline of high flows through the week. Flows in the forecasted range are still below defined “bankfull” and flood stages for the area. These additional flow releases are not anticipated to result in flooding to any of the communities along the associated waterways.

More detailed information about forecasted streamflows in the Colorado River basin are available from the Colorado Basin River Forecast Center at

The CROS program includes representatives from the U.S. Bureau of Reclamation, Denver Water, and Northern Colorado Water Conservancy District as owners and operators of upper Colorado River. The program was established in 1995 as part of the Upper Colorado River Endangered Fish Recovery Program, which is managed by the U.S. Fish and Wildlife Service. A wide array of partners, including Northern Water, the Colorado River Water Conservation District, Colorado Springs Utilities, Denver Water, the Grand Valley Water User Association, Orchard Mesa Irrigation District, Palisade Irrigation District, the National Weather Service, the Colorado Basin River Forecast Center, the Colorado Water Conservation Board, and Xcel Energy all participated in and contributed to this effort.