there is a Sashiko stitching that Asian quilts use a lot to represent water.. it looks easy enough for someone who hasn't done a lot of quilting to do. I'll try to discribe it but you'll have to qoogle sashiko or perhaps it's shown someplace on here.. Anyway, it is straight horizontal lines, and at random places there it a curve down (or up) to the next straight line.. the curved lines look sort of like a half circle.. wish there was a draw section here. words don't really do it.. But if you find an example you'll know its supposed to be water as soon as you see it. I think it would be perfect! and easy with just a bit of practice.