What does riprap specifically consist of?

Answer: B — Properly sized and graded rock or broken concrete

Riprap specifically consists of properly sized and graded rock or broken concrete. This material is used to protect shorelines, streambeds, bridge abutments, and other infrastructure from erosion and hydraulic wear caused by water flow. The rocks or concrete are carefully selected and placed in a manner that allows for effective drainage while providing a stable barrier against forces that might cause erosion. The effectiveness of riprap lies in its ability to absorb and dissipate energy from water, thus reducing the velocity of flowing water and minimizing soil erosion. The size and grading of the materials are essential for ensuring stability and preventing displacement during high flow conditions. Properly sized riprap can interlock and form a robust protection layer, which helps maintain the integrity of structures and natural landscapes.