I am debating what sort of manmade pond might be possible, as I enjoy ducks and geese in addition to my chickens. I purposely got muscovies since they don't require a pond, and geese since they like grazing in fields, but still would like to build a small pond if I thought it was possible to keep it somewhat clean. Any thoughts? they are so messy and poop so much, I just wonder if it is possible to keep a small pond clean. I was thinking something with a liner since our soil is so sandy.