Typically, 12" (300mm) of excavation to accommodate one layer of Flex MSE Bags on top of 6” (140mm) of gravel is required subgrade to lock the toe of the wall into place. One of our tallest GeoBag walls in Western Canada, 39ft (12m), has only a single row of Bags buried at the bottom of the wall. Engineered walls can specify additional layers of Bags subgrade depending on soils, hydrology, and surcharge. Walls built in waterways should consider the effects of scour on the ends and bottom.