I've often wondered why modest courses designed on flat sites and built on small budgets don't utilize this technique more often, with or without actual water. It doesn't seem too hard a thing to do (or to conceive of doing): i.e. design and build your Par 4 or Par 5 or short Par 4 and shape/bunker the green with such a hazard already in mind, and then at the end have a guy on a bobcat or a couple of guys with shovels dig out a shallow, angled trench all the way across the fairway and cover the sides & bottom of the trench with on-site rocks and gravel -- aka, a dry river/creek bed that's 240 yards out on the preferred side and that angles all the way down to 180 yards out on the safer side. Seems an easy way to add at least some interest and challenge to an otherwise nondescript golf hole, and a cost effective way of sprucing up some uninteresting topography.