I have a ton of Muscovies right now. I have 2ea. 2 gl black rubber bowls, 1 kiddie pool, & a 6' X 18" deep, Snapset pool fm Wal-Mart @ $15.00, that they love and can dive under the water in. Yesterday saw them swimming under the water then they would burst out and over the side and run down the hill flapping their wings, run back up and jump over the side into the pool and do it again.
The cat was staring at them as if they had gone crazy!
Here is the Snapset:
It took them a week to trust getting up into the pool but now they love it. Easy to empty or add a little extra water when they splash/dump some out.
Mine is in-between these extremes of building elaborate ponds and wash tubs.
I went with one of those black stock tanks at Tractor Supply. The 50 gallon size is a good size for my 3 Calls. it is about 18" deep, so they can dive. It is approximately (I'm guessing) 3' x 5'.
It is thick and sturdy and should last a lifetime. It cost $67.00.
I plumbed a drain into it for easy draining. Easy draining is very important because you have to drain A LOT!
Mine have two pools of this size ( small ) and then they have two of the large kiddy pools. Sometimes I give them the bottoms to rabbit cages, like the plastic ones.