I have been thinking of building a duck and goose pond, and some of your ideas are fantastic! If I can run a thought by you guys... I was thinking of putting in a bottom drain like that, but instead of a ball valve like you have I was thinking of running the drain to the pump so that it will be sucking the water from the bottom and hopefully remove more of the waste. Then when I wanted to drain it I could just hook an outlet hose to the pump to direct the water to where I want it to go. I am also thinking of putting heat tape from the drain to the pump so maybe between the water movement and the heat tape, maybe it would keep the water open through a North Dakota winter? Thoughts?