Every hunter seems to have a different opinion on water levels and how they effect duck hunting. most of it is subjective to where they personally hunt. my spots are better when there is less water. i hunt a huge swamp that has a creek running through the middle of it. when water levels are low the ducks concentrate only in the creek, which is 25 feet wide. we whack the hell out of them. when water levels are higher, the entire area is a swamp roughly 200 yards wide so the ducks drop in everywhere and dont bunch up.
other hunters, especially down south, like higher water levels because they are anticipating farm fields being flooded by the high water which will attract ducks to feed...... its just a very subjective question.......