Opting for a 'mole barrier' is one of the best options to keep the moles from damaging the soil. If your lawn is placed near a wood or a field where moles are plentiful, burying sections of galvanized hardware cloth or aluminum sheathing to a depth of 24" with about 3 feet wide can take care of the problem to a larger extent. Ensure you leave about 6 inches exposed above the soil, and about 3 inches bent forward on the bottom (towards the source of the moles) to prevent moles from digging underneath.