Yes, the depth for your pond depends on clarity of your water, and how deep the sunlite can penetrate. To keep the cattail zone as narrow as possible, make the banks steeper. For my needs, I like going as flat as possible to the water's edge, so I can easily use a lawnmower. Than go steep to limit the band of cattails, to about 3 feet. I have lot of suspended clay, so that is deep enough, and just about the right depth for the bluegill beds. Of course, than there is the 2 ft level drop between summer and winter...
