Loose pieces of rock placed on an embankment to prevent erosion are called?

• A. Spoils
• B. Riprap
• C. Draglines
• D. Consolidation

Answer: (B)

Protecting an embankment from erosion is achieved by placing loose rock that acts as a barrier to slow and dissipate the energy of flowing water. This is called riprap. The stones are large and angular so they interlock and stay in place on the slope, creating a rough surface that reduces soil loss at the base. Riprap is commonly used on riverbanks, shorelines, and around outfalls where water or wave action can erode the soil. Spoils refer to excavated material removed from a site, not a protective rock layer. Draglines are the excavation machines used to move earth, and consolidation means compacting or stabilizing soil—not the protective rock cover. So the correct term for the protective rock layer is riprap.