117 Cubic Feet per Second of water is being discharged/released from the lake.
I have no idea what inches avail means
As for perct util...I "think" that means percent utilized of the flood pool. At 45% the lake is almost half way into the flood pool. At 100% water would be out of control. It would be high enough that it would run over the flood gates,crest the dam or go through a spike dam pending on what setup the lake has.