U.S. Fish And Wildlife Service:
LAKEWOOD, Colo. – Coordinated releases from a series of Upper Colorado River Basin reservoirs began Saturday, June 3, and are anticipated to continue through this week as part of the Coordinated Reservoirs Operations Program.
The US Bureau of Reclamation, the Colorado River District, Denver Water and Northern Colorado Water Conservancy District as owners and operators of upper Colorado River reservoirs have mutually agreed to modify their operations to benefit the endangered fish of the Upper Colorado River Basin.
The Coordinated Reservoir Operations (CROS) program was established in 1995 as part of the Upper Colorado River Endangered Fish Recovery Program. The purpose of the Coordinated Operations is to enhance spring peak flows in a section of the Colorado River upstream of Grand Junction, Colo. Determined to be critical to the survival of four endangered fish species: the Humpback Chub, Razorback Sucker, Bonytail and the Colorado Pikeminnow. The higher peak flows remove more fine sediment from cobble bars that serve as spawning habitat for the endangered fish. In years with sufficient snowpack, surplus inflows to the reservoirs can be passed downstream to benefit these fish without impacting reservoir yields or future beneficial water uses.
Coordinated Reservoir Operations were most recently conducted in 2016, 2015 and 2010. In 2011 and 2014, wet conditions caused streamflows in certain areas of the basin to approach or exceed levels associated with minor flooding, so CROS was not performed. In 2012 and 2013, reservoirs did not have surplus inflow to contribute due to extremely dry conditions.
Managers of the reservoirs completed a conference call June 2, agreeing to voluntarily run the program this year. Planned reservoir operations as of June 2 are described below. Release and flow amounts are approximate. Most reservoirs will step up releases over the next several days, hold at a constant rate for 3-7 days, and then wind down releases.
Green Mountain Reservoir, operated by the Bureau of Reclamation, will increase releases from 418 cubic feet per second (cfs) to powerplant capacity of around 1400 cfs. Releases from Green Mountain include inflows bypassed by Dillon Reservoir, operated by Denver Water, that will be increased by approximately 100 cfs during CROS.
Denver Water also operates Williams Fork Reservoir, which is releasing 200 cfs. Releases will likely increase to approximately 600 cfs over the coming week to bypass increasing inflows.
Willow Creek Reservoir, operated by the Bureau of Reclamation and Northern Colorado Water Conservancy District, is releasing 90 cfs. Releases will increase this week to roughly 600 cfs by curtailing pumping operations to Granby Reservoir and bypassing those inflows instead.
Wolford Mountain Reservoir, operated by the Colorado River District, is passing inflows of 350 cfs. Outflows will be increased to around 600 cfs for approximately five days.
Ruedi Reservoir, operated by the Bureau of Reclamation, is releasing 182 cfs and will increase releases to approximately 600 cfs over the next few days.
The Colorado Basin River Forecast Center (CBRFC) will incorporate these planned reservoir operations into their streamflow forecasts. Based on weather forecasts and planned reservoir operations, flows in the Colorado River near Cameo (upriver of Palisade, Colo.) are anticipated to be approximately 14,000 – 17,500 cfs, June 7 through June 12, with the highest flows Thursday or Friday June 8 or 9. Flows in the forecasted range are still below defined “bankfull” and flood stages for the area.
More detailed information about forecasted streamflows in the Colorado River basin are available from the CBRFC website at www.cbrfc.noaa.gov. A map-based interface allows viewing of hydrographs detailing recent, current and anticipated flows.
For more information, contact Don Anderson, U.S. Fish & Wildlife Service, at 303.236.9883, firstname.lastname@example.org, Michelle Garrison, Colorado Water Conservation Board, at 303.866.3441, ext. 3213, email@example.com or James Bishop, Bureau of Reclamation, at 970.962.4326, firstname.lastname@example.org.
The Upper Colorado River Endangered Fish Recovery Program is a cooperative partnership of local, state and federal agencies, water developers, power customers and environmental groups established in 1988 to recover the endangered fishes while water development proceeds in accordance with federal and state laws and interstate compacts.