I second Dave's thought. I inherited an 8 acre pond in central texas that is close to 40 feet deep in spots. The pond is fed by runoff rain and a spring, but awhile back during a year long drought the spring stopped flowing and we had no runoff rain. The water level dropped a good 8-10 feet so the depth of the lake was crucial and my fish stayed in good condition despite the situation. To my knowledge I have never had any negative effects of this lake being so deep. I always want more water than not enough.
