Aspinall Unit update: Flows in the Gunnison Gorge and Black Canyon should remain at 1,400 cfs for a while yet

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From email from Reclamation (Dan Crabtree):

The Uncompahgre Valley Water Users are beginning to increase diversions from the Gunnison River. Consequently releases from the Aspinall Unit are increasing a corresponding amount. Today, releases from Crystal were increased by 200 cfs to 1,800 cfs, to match the Water Users’ diversion increase. Flows in the Gunnison Gorge and Black Canyon should remain at 1,400 cfs for the time being. This is significantly higher than last year at this time (550 cfs) due to the above average hydrologic conditions.

We are beginning to plan for spring runoff operations, including operations related to the Crystal Exciter Realignment. The Crystal work will take place the week of April 18th and will require flow through the powerplant to vary on an hourly basis on April 20th and possibly the 21st. However, any increases or decreases in flow from the unit during calibration will be compensated through bypasses, thus fluctuations in the river will be minimal. Due to the current runoff forecast, we anticipate releases during the Realignment to be at or near the powerplant capacity of 2,150 cfs.

Speaking of the forecast, throughout the snowfall season, the Colorado Basin River Forecast Center (CBRFC) has been providing a fairly consistent April through July forecast of 800,000 af runoff into Blue Mesa Reservoir. If the May 1st forecast remains at 800kaf, the one day peak target for the Black Canyon water right is 6,369 cfs, which will likely require a total release from Crystal in excess of 7,000 cfs (combined Crystal powerplant and bypass is about 4,300 cfs; expect a Crystal spill of over 2,700 cfs). Reclamation plans to operate the Aspinall Unit to allow this peak target to be met sometime between mid-May and early June.

We will be discussing this in more detail at the April Aspinall Operations meeting on April 21st starting at 1:00 p.m. in Reclamation’s Western Colorado Area Office, Grand Junction. If you have any questions or concerns, please contact Dan Crabtree or Erik Knight by replying to this email or call 970-248-0600.

More Aspinall Unit coverage here.

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