This was a unique retaining wall we did made out of earth bags! This concept is more cost effective and should last for decades! You can see some pictures of the process. First step with any wall is a foundation that is let level and allows for water to drain away from the base. On top of that we filling long bags with a soil mix of predominately clay, and tamped them on top of one another. Since this was such a large wall, we put drain pipes through the wall catch water in the soil on the backside and let it drain through. In the end, the whole structure is covered with a mortar that seals it and protects it from water and sunlight.