The time has come for the annual Spring Flush! Every year we have a timeout in our fishing on the Gunnison River starting below the Crystal Reservoir Dam and throughout the canyon. Don't let this get you down as fishing on other rivers in our area has been great and will provide you a place to keep chasing trout throughout the flush on the Gunnison River. Check out our river reports at https://montroseanglers.com/a/info/river-reports for an updated fishing report on our local waters or come by the shop for our fly fishing guides current reports.
The Bureau of Reclamation released there latest Aspinall Unit Operations report on May 10th, releasing information on the Flush through the Black Canyon of the Gunnison/Gunnison Gorge. The report includes target flows through the canyon, Reservoir Fill %, estimated flows, and more for the summer 2024. The report states, "The May 1st forecast for the April – July unregulated inflow volume to Blue Mesa Reservoir is 570,000 acre-feet. This is 90% of the 30 year average. Snowpack in the Upper Gunnison Basin peaked at 108% of average. Blue Mesa Reservoir current content is 554,000 acre-feet which is 67% of full. Current elevation is 7487.0 ft. Maximum content at Blue Mesa Reservoir is 828,00 acre-feet at an elevation of 7519.4 ft.
Based on the May forecasts, the Black Canyon Water Right and Aspinall Unit ROD peak flow targets are listed below:
Black Canyon Water Right
The peak flow target is equal to 4,035 cfs for a duration of 24 hours.
The shoulder flow target is 330 cfs, for the period between May 1 and July 25.
Aspinall Unit Operations ROD
The year type is classified as Average Dry.
The half bankfull target is 8,070 cfs and the duration target at this flow is 10 days.
The peak flow target is the same as the half bankfull target.
Pursuant to the Aspinall Unit Operations ROD, releases from the Aspinall Unit will be made in an attempt to match the peak flow of the North Fork of the Gunnison River to maximize the potential of meeting the desired peak at the Whitewater gage, while simultaneously meeting the Black Canyon Water Right peak flow amount. The latest forecast for flows on the North Fork of the Gunnison River shows a period of high and possibly peak level flows beginning on May 20th.
Therefore ramp up for the spring peak operation will begin on Tuesday, May 14th, with the intent of timing releases with this potential higher flow period on the North Fork of the Gunnison River. Releases from Crystal Dam will be ramped up according to the guidelines specified in the EIS, with 2 release changes per day, until Crystal begins to spill. The release schedule for Crystal Dam is:
Crystal Dam will be at full powerplant and bypass release on May 18th and Crystal Reservoir will likely begin spilling on the same day. The peak release from Crystal Dam should be reached on May 21st. The flows in the Gunnison River after that date will be dependent on the timing of the spill and the level of tributary flow contribution. Estimates of those numbers will be determined in the upcoming days.
The current projection for spring peak operations shows flows in the Gunnison River through the Black Canyon peaking around 5700-6000 cfs in order to achieve the desired peak flow and duration at Whitewater. Actual flows will be dependent on the downstream contribution of the North Fork of the Gunnison River and other tributaries. Higher tributary flows will lead to lower releases from the Aspinall Unit and vice versa.