From email from Reclamation (Erik Knight):
Flows in the Gunnison River have dropped to ~350 cfs today to accommodate the sonar mapping exercise at the Crystal Dam stilling basin.
Maintenance and testing of both power generators at Blue Mesa Dam will also start today – this is scheduled to be finished within 10 days. During this time there will be no power generation at Blue Mesa Dam. In order to minimize the amount of bypass water at Blue Mesa Dam, releases at Crystal Dam will remain at 300 cfs until the Blue Mesa power plant is back online. Therefore flows in the Gunnison River through the Black Canyon will continue to be around 350 cfs until further notice.
More Aspinall Unit coverage here.