From the Montrose Daily Press:
During the 24-hour release, up to 4,300 cubic feet per second poured out of the lake and into the river…The water was released by the U.S. Bureau of Reclamation under a 2008 court decree that provides Black Canyon National Park with a federal reserve water right to protect riparian resources. The release is beneficial to river life downstream and helps the Gunnison to revert to flows and conditions more in keeping with the natural environment before construction of the Aspinall Unit, which encompasses Crystal Reservoir, Blue Mesa Reservoir and Morrow Point Reservoir.
Check out this very cool video of the event from William Woody and The Grand Junction Daily Sentinel.
More Aspinall Unit coverage here.