My trout pond is about as steep as it comes maybe even steeper than 45 degrees. However after my last harvest of trout and draining I found slumping was minimal and what slumping took place was close to the bottom. Probably a lack of slumping due to my soil which has a high clay content.
As far as applying stone. I applied my landscaping stone with a rented bobcat and really did not have much go too far below the water line. It seems to pile on itself and does a minimal amount of sliding. But it is possible if you went with a larger size than the landscaping stone you could have more roll down.
It looks great and even though the pond is only 88 feet long, when we get high winds the stone works great as a rip rap and does not allow the bank to get stirred or undercut. The amount of stone I needed around the entire pond was about $600.00 worth (two loads) and on one side of the pond I have a good four feet of bank covered with it.
