Currently it is 10' at the deepest. About half the pond is pretty shallow. I have turbid water which prevented any plant growth to provide O2 during the summer and a fairly large influx of fall leaves to gobble up oxygen at the bottom. Considering that surface O2 infusion from wave action is pretty slow, I imagine that I've been running on pretty low O2 levels since this thing filled up. The severe freeze this winter sealed up the top with 8"-10" of ice and when turnover happened it was all over with.