cant spell ignrant so i plead dumb to this one. seems like it would take a couple of feet of material over the liner to not get saturated and slide. i know of a small goldfish pond where they used 1 to 2" creek bed gravel on a 4 to 1 slope that stayed in place. a refinery close had a liner that wouldnt stay in place very well so they put 2" gravel in bottom and on some pretty steep slopes and it stayed in place but they probably had 6" gravel on it. thats all i know.
