I renovated my yard last Spring with Hydroseeding. I now realize I did things a little backwards. I have a problem with drainage in certain areas near the bottom of a hill in the back yard. The rear yard is 15k sq feet. My yard is mostly clay and they water just doesn't make it's way through the soil because it is so compacted. I aerated last fall and it did not sem to help yet. I have underground sprinklers. I know I should have amended the soil before hydroseeding but it's too late now. My lawn does look nice, but I need to break down the clay so those standing puddles of water can drain down into the soil. Any ideas?