What are your ideas for tree wells on my sloped clay slab? When i make a berm at the drip line, the water still runs under the pile of clay clods. My lemons-to-lemonade idea is to put that clay with water in the electric cement mixer then pour a thick goo into forms at the drip line. Anybody done this in the last 400 years around here? I don't know where the "Ask the Antropologist" forum is, but water catchment for agriculture has a long traditon in arid areas.