well i'm certainly no authority on power production but i do know that back in the before timesthey used to cut off the spigot at5-6 pm ,down to about 150 cfs, and throw open both gates to the tune of 1800 cfs every morning around 5 am in time for the daily house lights and factories to get chugging .
i would guess they weren't running 1100 cfs more than they needed to turn the highest profit that they could.
of course i believe they redid the turbines since then which may have changed things.