Ah, backabit, you are not in nearly as bad a shape as I originally thought. And you even have the aeration thing taken care of. Sounds like a nice pond. And from what others say, the rock might work. I have seen ponds where the 45 degree undermines and turns to vertical but experienced pond builders probably had this in mind and probably made sure you were okay. Another option would be a low-profile bulkhead since it is a limited area, but this may not be the look you are after. And it is relatively expensive too. I all for keeping it simple and as natural looking as possible. You might also consider planting native wetland plants in some of these areas for stabilization and added attraction.
