I have 140 ft. long 4ft. high retaining wall. I built a french drain along the wall that empties into a drainage system. But since the soil is pretty much clay, other than standing water it is slow to drain, leaving that area of grass wet most of the time. I'm looking for ideas to amend the soil to improve the speed of drainage. I have a few tons of sand left over from some projects. Would slowly adding sand to the area, say 1/2 inch every 3-6 months help, or would it just wash away? Any other ideas?
Thanks
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