We have an old, filled-in cistern next to our milk house and barn that would be really cool as a duck pond. I've been planting millet and sorghum in there for the last few years with little success and my husband came up with the pond idea. It sounds good to me. I've never built a pond though. There's no place to drain the thing anymore and with ducks, that's absolutely necessary so I was thinking a pump? Ideas?