I keep water action small in the winter, as long as the beak can get in a sm tub of water, like the top of a cake carrier . . . .and fill the sand box every once in a while with cool water for a swim . . . .Keeps water issues down to a minimum. I have muscovey, if that makes a diff and they live in the hen house.
I thought I had read that Muscovy aren't really water birds.
I keep the water action low in the winter, too, as much as possible. They don't get their rubbermaid tub or the kiddie pool. They get a small 5 gallon black bucket of water, with hot water in it in the morning, and in the evening if it's completely frozen solid. They still manage to make a giant mess and cram themselves in the bucket.
Let me see if I can find a picture...
I apparently don't have one, but I do have a picture of their glacier at the end of winter... when everything else is melted. And you can fit 2 pekins in that bucket, plus the head of another duck.