A 5' elevation drop, and return, seems pretty drastic, and I would think there would be other unknown consequences. But that's just some thoughts. I have no idea.
I think the biggest drastic risk would be a heavy rain storm while the pond was drawn down. I fear water running down the usually submerged pond slopes could result in some nasty erosion of soft sediments with few plant roots. (I think the OP has enough water flow to quickly re-fill the pond?)
Don't know how the fish population would like it overall, but that is not in my area of expertise. However, I am pretty sure it would pi$$ off the spawning bass!
