It took awhile, but I found the BuRec most probable releases for Lake Powell at http://www.usbr.gov/uc/water/crsp/studies/crsp_gc.txt
To get approximate average daily releases in cfs, divide "Total Release" (1000 acre-feet) for the month by 60.
April through June 2010 are projected to release 600,000 acre-feet each month, works out to 10,000 cfs average release, or the daily 8-12,000 cfs.
I am on a May 26 launch, would rather the 806,000 projected for July 2010, that will be 10-15k.
These numbers can change, usually near the end of the month prior, based on inflows, etc.