The project started with a design for a retaining wall. The soil was clay silt which is highly erodible. After construction, water from a parking lot uphill was pouring over a curb which made gullies 5’ wide and 5’ deep in a matter of months. The wall was going to fail if we didn’t do something.
We filled in the gullies then used all organic materials to make a thin blanket across the hillside. The slope from top to bottom was about 35% which is so steep the soil would slump out from under our feet if we tried to walk on it. We had to throw the material because we couldn’t walk on it. No plastic or coir erosion blankets were used and that was a considerable saving on the project cost.
We had the material and a thick tea on the hillside by 4 pm. We had heavy rain at 3 am the following morning. Tiny rivulets started in two places in the rain. We raked them out, hit it with more tea and the soil has never eroded again. In fact, 4 months later we went back to plant big grasses into the hillside. We could walk on it and when we dug in to plant the grasses we had 12” of deep brown soil. The light brown clay silt had, in fact, changed character so completely and has only gotten better.