Elowan I apologize for such late replies… my work has me ball and chained at the moment… 🙁
You can use sand dunes for this. Then warp the dunes a bit by using the Displace post effect. You can also use the intentional orphan method explained in this video:
This method allows for the sand to warp against a structure, like rock.
If you want the smooth underwater look, then hydro is the erosion you want to use. Mix it up with a recurve node as well and play with the settings to get some cool looks. You can even use the Aperture Node to get some decent looking effects for under water looks.
There are a lot of ways to get around it. Perhaps I'll submit a request for a quick start to show case more water works. Underwater preferably.