The corp is not responsible for normal electrical generation releases from either Grand Lake or Hudson, that is controlled by GRDA. The corp does manage flood gate operations on these lakes.
GRDA dispatches their power based on demand from the Southwest Power Pool, The Corp dispatches based on Southwest Power Administration demand.
The Fort Gibson generation release schedule is located here
Hydropower Release Schedule , I have not located any online schedule for GRDA units.
I fish the upper river section of Gibson quite a bit and understand your frustration.