Hello Everyone, I have a lawn mowing customer that has a drainage and washout problem. The water is starting at the top of the patio running around the the cement wall down the grade to the flat ground and under the cement slab and ponds around the house. What advice could I give the homeowner on correcting this problem. The pictures show an overview of the area: Blue is where the water is flow and the red areas are point downgrade. Thank you for your opinions.