From the Bureau of Reclamation:
* * * * * U P D A T E -- June 5, 2023 * * * * * *
Use Caution when recreating in or around the Green River below Flaming Gorge Dam between June 6-14, 2023 pending hydrology, water will be colder than usual and will run high and swift. These conditions can quickly overcome even the strongest swimmer. Reclamation will perform a LTSP experimental release that will potentially include full powerplant releases (4,600 cfs) and bypass releases (+4,000 cfs), totaling 8,600 cfs. The experiment is authorized through the 2006 Flaming Gorge Record of Decision and is part of the adaptive management process to recover endangered fish.
Forecasted (tentative) hourly release schedules can be found by visiting the Colorado River Basin Forecast Center at this website: Flaming Gorge Reservoir. This data is considered the most likely scenario given the current forecast, is general, and is subject to changing conditions. Down ramping is anticipated to occur early the week of June 12, 2023. Reach 2 (measured at Jensen) peak magnitude objective is to be ≥14,000 and <20,300 cfs.
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Summary of Flaming Gorge Notification Sent June 2, 2023
In order to achieve the goals of the LTSP, Reclamation will release to full powerplant capacity (~4,600 cfs) and bypass. Bypass release can measure up to an additional ~4,000 cfs over powerplant capacity, for a maximum release of ~8,600 cfs from Flaming Gorge Dam. The Flaming Gorge Dam release schedule below shows the approximate timing of flows for implementation of the LTSP experiment:
NOTE: Bypass will be used at Flaming Gorge Dam to achieve releases greater than ~4,600 cfs in the table above. The hourly release schedule above is an approximation of releases. All data is provisional and is subject to change. The table was created on 6/2/2023.
The Flaming Gorge Dam releases for the LTSP experiment are currently planned to stay at ~8,200 cfs through the weekend of Sunday, June 11, 2023. Reclamation plans to initiate the ramp down portion of the LTSP experiment early in the week of Monday, June 12, 2023. A detailed ramp down release schedule will be released in a subsequent notification. All dates and releases are provisional and subject to change.
“As of May 8, 2023 (end of day), Flaming Gorge Reservoir pool elevation is 6012.21 feet, which amounts to 72 percent of live storage capacity. Unregulated inflow volume for the month of April is approximately 188,000 acre-feet (af), which is 150 percent of the average April unregulated inflow volume. The current average daily release is 800 cfs.
The 2023 DROA Plan is being finalized and will be provided through processes outlined in the DROA Framework, https://www.usbr.gov/dcp/droa.html pages.
A new operation will be finalized in May 2023, and this will contain an operation plan from May 2023 through April 2024.
Spring Release -- The Larval Trigger Study Plan to assist in the recovery of the Razorback sucker (protected under the Endangered Species Act) is the next operational plan to occur this spring. The adaptive management experiment is triggered by appearance of razorback sucker larvae which is correlated to the weather. Current models show that the trigger could occur in early June, pending hydrology and weather. Below is a description of the likelihood of the trigger occurring. The mean calendar date of the first capture of razorback sucker larvae (i.e., the "larval trigger") is May 28 (median May 27) and ranges from May 7 to June 24. Historically, 50% of first captures occurred between May 21 and June 2; 75% occurred between May 16 and June 4. In general, first capture of larvae is earliest in years characterized by low flows and/or warmer conditions, and latest in years characterized by high flows and/or cooler conditions. Pending the timing of the trigger and Yampa River flows, the goal is to achieve greater than 18,600 cfs for at least 5 days in Reach 2, near Jensen Utah. Releases from Flaming Gorge Dam will vary to meet target flows in Reach 2.
The May unregulated inflows into Flaming Gorge for the next three months projects above average. May, June, and July forecasted unregulated inflow volumes amount to 415,000 af (167 percent of average), 490,000 af (126 percent of average), and 207,000 af (103 percent of average), respectively. The May water supply forecast of the April through July unregulated inflow volume into Flaming Gorge Reservoir is 1,300,000 acre-feet (135% of average). Due to the May official forecast Upper Green April – July forecast being at a 31% exceedance value, spring operations will use an average hydrologic classification operation.
To view the most current reservoir elevation, content, inflow and release, click on: Flaming Gorge Reservoir Data.”
What this means:
High flows through June 14th.
Fish worms and scuds.
