What is a backing layer in slope protection?

In the context of slope protection, a backing layer refers to a layer of graded rock. This layer plays a crucial role in stabilizing slopes and preventing erosion. Graded rock is used because its varying sizes create a stable structure that can effectively absorb and redistribute the energy of water runoff. This helps to protect the underlying soil from erosion while allowing for drainage.

The use of graded rock as a backing layer also enhances the physical integrity of the slope. It provides a rough surface that encourages the establishment of vegetation over time, which further contributes to slope stability and erosion control. This approach is widely accepted in engineering and environmental management practices dealing with slope protection. Other options like vegetation, water-resistant membranes, or organic mulch, while beneficial in certain contexts, do not serve the primary function of a backing layer in the same effective way that graded rock does.