Aspinall Unit operations update (April 13, 2022): Deliveries through the Gunnison Tunnel bumping up to 1,000 cfs

East Portal Gunnison Tunnel gate and equipment houses provide for the workings of the tunnel.
Lisa Lynch/NPS

From email from Reclamation (Erik Knight):

Releases from the Aspinall Unit will be increased from 900 cfs to 1200 cfs on Wednesday, April 13th and then from 1200 cfs to 1300 cfs on Monday, April 18th. Releases are being increased as diversions to the Gunnison Tunnel continue to increase. Currently snowpack in the Upper Gunnison Basin is 100% of normal and the forecasted April-July runoff volume for Blue Mesa Reservoir is 83% of average.

Flows in the lower Gunnison River are currently above the baseflow target of 1050 cfs. River flows are expected to stay at levels above the baseflow target for the foreseeable future.

Pursuant to the Aspinall Unit Operations Record of Decision (ROD), the baseflow target in the lower Gunnison River, as measured at the Whitewater gage, is 1050 cfs for April and May.

Currently, Gunnison Tunnel diversions are 600 cfs and flows in the Gunnison River through the Black Canyon are around 335 cfs. After these release changes Gunnison Tunnel diversions will be around 1000 cfs and flows in the Gunnison River through the Black Canyon will be near 350 cfs. There will be a period of higher flows in the Gunnison River through the Black Canyon between Wednesday, April 13th and Monday, April 18th. Current flow information is obtained from provisional data that may undergo revision subsequent to review.

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