From email from Reclamation (Dan Crabtree):
Releases from the Aspinall Unit have begun to decrease this afternoon. Provisional data from the USGS shows the Black Canyon 24 hour peak target flow of 6,793 cfs is expected to be completed by about 7:00 p.m. this evening. Current Black Canyon flow is 7,040 cfs. The Unit will continue to be ramped down over the next several days until reaching a flow of about 3,100 cfs next week. The instantaneous flows at Delta, Colorado reached a maximum of 13,700 cfs this morning inundating small lower portions of agricultural fields west of Delta. The instantaneous flow at Whitewater reached a maximum of 14,900 cfs this afternoon.
More Aspinall Unit coverage here.