Developers remove topsoil from their sites leaving clay exposed to vehicle traffic. The clay particles are very small and will pack down and seal the surface. Once topsoil is added over the clay, water will sit on the clay surface and keep the topsoil moist but won’t drain off.
Cut a shallow and wide ditch.
Fill ditch with slotted pipe and rock
Cloth protects the rock, topsoil gives the sod a good base to grow into.