The second portion of the down ramp schedule from May 27, 2015 through May 31, 2015 has been determined. The base flow average daily release rate will remain at 1,700 cfs with the hourly pattern shown until further notice. It is anticipated that releases will remain at 1,700 cfs through September 30, 2015. Base flow releases are subject to observed hydrology and all projections may change.
The above-average precipitation during the beginning of May increased the projected Flaming Gorge unregulated inflow volume from 570,000 acre-feet (58% of average) to 690,000 acre-feet (70% of average) in the May midmonth forecast.
Unregulated inflow into Flaming Gorge Reservoir during the month of April was 112,000 acre-feet (AF), or 84 percent of average. The reservoir elevation is 6,026.75 feet. Observed inflows are averaging 3,000 cubic feet per second (cfs).
Inflows for the next three months are projected to be below average: with May, June and July forecasted inflow volumes at 185,000 AF (75% of average), 190,000 AF (49% of average), and 83,000 AF (39% of average), respectively.
SPRING PEAK RELEASE
As in the last four years, Reclamation again will be involved in a cooperative experimental program (Larval Trigger Study Program or LTSP) this year where the capture of endangered larval razorback sucker is the “trigger” to increase releases from Flaming Gorge Dam this spring. Reclamation plans to coordinate with scientists involved in real-time monitoring on the river to determine the first appearance of larval razorback sucker. Biologists began sampling light traps in the middle Green River yesterday, Monday, May 4, to determine the initial presence this year. The U.S. Fish and Wildlife Service (FWS) will be regularly sampling for larval Razorback Sucker and data will be processed and shared when available. Upon detection of larval presence, Reclamation will increase releases from Flaming Gorge in an effort to entrain larvae in backwaters where they have a better chance of survival. Reclamation anticipates at least 3 days notification in the event larval presence is reported and Flaming Gorge Dam releases are increased. Reclamation will determine the appropriate level of releases from Flaming Gorge Dam to achieve the goals of the experimental program, and is planning on releasing above powerplant capacity (~4,600 cfs) to full bypass (8,600 cfs) to achieve those goals.
Kevin Bestgen, the scientific point of contact for prediction of larval emergence, shared the following information with Reclamation. “The best predictor of first presence of larvae is spring peak flow magnitude in the Yampa River. There is a definite temporal component to this as higher magnitude spring peaks occur later, and lower ones earlier. Whether flow is the actual driver or not is uncertain; I rather think it is not but it appears to be a useful metric for first presence prediction... The highest flow point … was 2011; that year the temperature model predicted first presence late, by 2 days. In 2012, the model predicted first presence within 2 days, but last year was somewhat late missing by 5 days because temps were fluctuating and cool.”
To view the most current reservoir elevation, content, inflow and release, click on: Flaming Gorge Reservoir Data.
WORKING GROUP MEETING
The next Flaming Gorge Working Group meeting is scheduled for August 27, 2015, at 11:00 a.m. to be held in the Utah Department of Natural Resources building in Vernal, Utah. The Flaming Gorge Working Group is an open public forum for information exchange between Reclamation and the stake holders of Flaming Gorge Dam. The public is encouraged to attend and comment on the operations and plans presented by Reclamation at these meetings. Meeting notes from past Working Group meetings are posted on the Working Group webpage. For more information on this group and these meetings please contact Heather Patno at 801-524-3883.
Updated May 26, 2015
Email comments/inquires to: ResourceMgr@usbr.gov