Peak Flows Scheduled for Upper Colorado River

Palisade, Colorado – Coordinated releases from a series of reservoirs in the Upper Colorado River Basin have been sheduled to provide peak run-off in early June. Coordinated reservoir operations begin earlier this month as part of an ongoing effort to support endangered fish in the Upper Colorado River Basin. Flows at in the Colorado River near Cameo (Big Sur) are anticipated to be approximately 14,000 – 17,000 cfs from June 7^th through June 12^th, with the highest flows on Thursday or Friday June 8^th or 9^th. Flows in the forecasted range (14,000 – 17,000 cfs) are below defined bankfull and flood stages for the area, and the wave features at Big Sur is unlikey to materialize this year.

Photo Courtesy of Peter Holcomb

The Coordinated Reservoir Operations program was established in 1995 as part of the Upper Colorado River Endangered Fish Recovery Program.  Its purpose is to enhance spring peak flows in a section of the Colorado River upstream of Grand Junction, Colo., determined 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 on downstream to benefit these fish without impacting reservoir yield.

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 peak augmentation 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 on June 2, agreeing to voluntarily run the program this year. Planned reservoir operations 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 ramp releases back down.

Green Mountain Reservoir, operated by the Bureau of Reclamation, is currently releasing approximately 418 cubic feet per second (cfs).  Releases are expected to increase to powerplant capacity of around 1400 cfs.  Releases from Green Mountain include inflows bypassed by Dillon Reservoir, operated by Denver Water, which will be increased by approximately 100 cfs during these Coordinated Reservoir Operations.

Denver Water also operates Williams Fork Reservoir, which is currently releasing 200 cfs.  Releases will likely increase to approximately 600 cfs over the coming week to bypass increasing inflows.

Wolford Mountain Reservoir, operated by the Colorado River Water Conservation District, is currently passing inflows of 350 cfs.  Outflows will be increased to around 600 cfs for approximately 5 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.

For more information, contact James Bishop, Bureau of Reclamation, at (970) 962-4326, jbishop@usbr.gov; Don Anderson, U.S. Fish & Wildlife Service, at (303) 236-9883, donald_anderson@usfws.gov or Michelle Garrison, Colorado Water Conservation Board, at (303) 866-3441, ext. 3213, michelle.garrison@state.co.us.