Verification of ODOT Rock Channel Design Procedures

The Ohio Department of Transportation (ODOT) uses Rock Channel Protection (RCP), referred to as Riprap, for energy dissipation to protect against scour at the outlet of culverts and storm drains. RCP is classified by size into Type A, B, and C Rock with the type, length, and depth of protection determined by the pipe diameter and outlet velocity and are shorter than the lengths designed by other accepted procedures for a given design flow, it was determined that the actual number of sites which had scour problems at the end of the rock was small, therefore, the Ohio design lengths have proved adequate. Verification of the current procedures or a replacement methodology is needed in order to provide adequate sizing of RCP at conduit outlets.