Hi all, I am a gardener, with some landscaping experience, and I have a client who would like a small terraced area part way up their steep garden so as to give easier access for gardening. I terms of design, I think a curved upright sleeper retaining wall would be best, however I have never built such a retaining wall. From my research I have come up with the attached construction. As I understand it, ideally 1/3 of the height of the sleeper should be in the ground, I expect the maximum height of the sleepers above ground to be 500mm, so I expect the depth of concrete to be 250mm. Is this is a good design? Would this give sufficient drainage? Is a depth of 250mm for concrete excessive? Any guidance would be much appreciated.