Hi, we just got a new pool installed in place of the old one. We have 2 ft of soil dug up round the outside, round the outside, round the outside, just a couple inches deep most of the way around. I want to lay river rock but I can't really find any good instructions. For example, how deep does the tench need to be? We also have part of the pool where the ground is higher, so the trench is much deeper. Should I build a retaining wall there? Do I lay the same amount of rock in those areas? Any other steps that may be involved? How does is actually keep the water away from the pool? Thanks!