Aspinall Project Notices

Blue Mesa

Project Notices

BUREAU OF RECLAMATION
Aspinall Unit
Summary of Spring Operations
June 10, 2016

The May 1st forecast for the April – July unregulated inflow volume to Blue Mesa Reservoir was 525,000 acre-feet. Based on the May 1st  forecast, the Black Canyon Water Right and Aspinall Unit ROD peak flow targets are listed below:

Black Canyon Water Right

The peak flow target was 3,349 cfs for a duration of 24 hours.

The actual peak flow was 5,100 cfs for a duration of 24 hours, occurring on May 23rd

The shoulder flow target is 300 cfs, for the period between May 1 and July 25.

Aspinall Unit Operations ROD

Based on the May 1 forecast the hydrologic category is Average Dry

The peak flow target was 8,070 cfs and the duration target at this flow was 10 days.

The actual peak flow was 9,900 cfs for a duration of 1 day, occurring on May 17th

There were 10 days of flows greater than 8,070 cfs achieved between May 16th and May 25th

Pursuant to the Aspinall Unit Operations ROD, releases from the Aspinall Unit were made in an attempt to match the peak flow of the North Fork of the Gunnison River, in order 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 forecast for flows on the North Fork of the Gunnison River showed a period of high flows beginning on May 15th.  Based on this forecast Aspinall releases began ramping up on May 11th to time with these higher flows. On May 16th the North Fork of the Gunnison River peaked at 3,140 cfs while the Gunnison River at the Whitewater gage reached a flow of 8,920 cfs. Flows on the North Fork of the Gunnison River remained above 2,000 cfs through May 24th. During this time flows on the Gunnison River at the Whitewater gage remained over 8,500 cfs with 6 of the 10 days over 9,000 cfs. Tributary runoff exceeded expectations almost every day during the 10 day half bankfull period.

Forecast for Future Aspinall Operations

The June 1st forecast for the April – July unregulated inflow volume to Blue Mesa Reservoir is 580,000 acre-feet. This is 86% of the 30 year average. Snowpack in the Gunnison Basin peaked at 88% of average but rainfall in the Gunnison Basin in April and May was above average. Blue Mesa Reservoir current content is 662,000 acre-feet which is 80% full. Current elevation is 7500.1 ft. Maximum content at Blue Mesa Reservoir is 829,500 acre-feet at an elevation of 7519.4 ft. Blue Mesa Reservoir is currently projected to fill to an elevation of around 7509 feet with an approximate peak content of 737,000 acre-feet. The reservoir has been filling rapidly due to high inflows and it appears that the next forecast could indicate a higher seasonal fill level for Blue Mesa Reservoir than currently estimated.

Flows in the Gunnison River through the Black Canyon are expected to remain in the 800 cfs to 1000 cfs for most of the summer months. There is a possibility that river flows would increase if Blue Mesa Reservoir is forecast to approach full capacity in the next couple weeks.

For questions or concerns regarding these operations contact:

Erik Knight at (970) 248-0629 or e-mail at eknight@usbr.gov
Ryan Christianson at (970) 248-0652 or e-mail at rchristianson@usbr.gov

Contact

Please contact the Operations Group via e-mail at ResourceMgr@usbr.gov for additional information.

Last Updated: 6/10/16