It would be better if it was bigger, and provided more depth of substrate. Lots of things will work, the question is, is it worth the trouble in finding out what does or doesn't work for an enclosure, when you could be concentrating on your husbandry and what is in the enclosure.
I doubt seriously that there is any place in the US where you can't find a trough. Perhaps you have to drive a hundred miles, but wherever there is livestock, there are stock tanks, and alot of people use them for hot tubs, and all sorts of things besides keeping monitors err... I mean providing water for horses and cows.
If these are young babies, you actually would be better off starting with something smaller, such as a glass tank, and let them grow into that first, before you move them to something bigger and harder to control. Just build out a glass tank like a trough, cover the top, small vent hole, light inside (for heat). You should start on a larger enclosure though, as they grow very quickly.
There are many ways to keep them, but I would highly recommend to keep it as simple as possible.
Good Luck,
--Robert