When I had my pond re-dug they cut a 6" ledge into the shoreline with a backhoe to make a shelf to hold the rocks (see picture below). A 4 oz. non woven landscape fabric was put down and cobblestones on top of that. The fabric is like a felt that's incredibly strong and rated to last 20+ years if it's covered with 6" of the sized stone that I have. My slope is 3:1 all the way around my pond and the rocks are staying in place nicely.

Here's an old thread with pictures that may help: http://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=177298 There's a video in that thread too but I don't think it's available anymore (maybe PM the poster).

[img:center][/img]

[Linked Image from i108.photobucket.com]