Ever since we moved into our home, the backyard grading has needed work. It basically slopes right into the back of the house. I put in a small trench a few feet away from the foundation to divert water around the house, which worked unless we got a heavy downpour.
Now I'm fixing it for good and renovating the yard to slope differently and adding two small terraces with french drains behind them, taking the water around the house to the ditch out front. I have a tractor and started by stripping off the useful topsoil, which was about 3-5" in most places. I then had to remove a few inches of really heavy clay soil, which I set aside in a separate pile. Then I worked it to get the actual grade I want/need, and set that pure clay aside for another project.
Now that I'm at finished grade, made up of basically pure clay, what should I do? If I put topsoil back I'll be right where I started, 4" higher than I should be. Should I chisel another 2-3" off this clay, then put 3" of topsoil back on top? I want to disturb this hard pan as little as possible so water has a properly sloped base to flow across and around the house.