The pond at my house (don't own it but have all the access I could ask for) has the potential for drastic fluctuations as well. At full pool it's 7 acres, I have a picture of it at about 10X20 yards in size, if that. Since the landowner doesn't seem to have much interest in the fishing side of it, I'm pretty much in charge of that by default. I wish it had the depth of yours, I think that'd solve a lot of potential problems.
