Aspinall Unit update: Black Canyon Water Right 24 hour peak flow target of 3,883 cfs set for May 18

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From email from Reclamation (Dan Crabtree):

Reclamation has set the 2010 spring operation plan for the Aspinall Unit. The May 1st Blue Mesa Reservoir April through July runoff volume forecast from the Colorado Basin River Forecast Center is 560,000 ac-ft. This results in a Black Canyon Water Right 24 hour peak flow target of 3,883 cfs. Reclamation plans to operate the Aspinall Unit to allow this target to be met on about May 18th. To accomplish this, releases from Crystal Reservoir will begin to increase starting tomorrow, [May 11] and ramp up at about 500 cfs per day, using two changes per day until a maximum release of around 5,000 cfs (depending on side-inflow fluctuations) is achieved on the 18th. This will require a spill in the neighborhood of 800 cfs at Crystal Dam. The spill will take place starting on Monday the 17th ending on Wednesday the 19th. Flow decreases should begin on May 19th. Again, two changes per day totaling 400 cfs per day and stabilize in the Black Canyon and Gunnison Gorge on about May 26th in the 700 – 800 cfs range. Please reply to this email or contact Dan Crabtree at 970-248-0652 with questions regarding this operation.

Here’s a late addition:

Starting at 8:00 a.m. releases will increase about 250 cfs with a second 250 cfs increase planned for 4:00 p.m. Similar increases will take place each day until the peak release of about 5000 cfs occurs May 18th. Ramp-down will begin on the 19th and flows should stabilize in the 700 – 800 cfs range around May 26th.

Please contact me with questions by [dcrabtree@usbr.gov] or call 970-248-0652.

Update: From email from Reclamation (Dan Crabtree):

We’ve had a few questions regarding the possible actual peak flows in the Black Canyon and Gunnison Gorge. The target peak in the Black Canyon is 3,883 cfs however, in order to accommodate diversions through the Gunnison Tunnel for the Uncompahgre Valley Water Users and compensate for possible side-inflow fluctuations, total releases from Crystal Dam will have to be about 5,000 cfs. Sorry for the confusion.

More Aspinall Unit coverage here.

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