U.S. Department of Defense


Date of this Version



Published in Hydraulic Engineering: Saving a Threatened Resource—In Search of Solutions: Proceedings of the Hydraulic Engineering sessions at Water Forum ’92. Baltimore, Maryland, August 2–6, 1992. Published by American Society of Civil Engineers.


Flow impingement, which occurs when approach channels direct flow into a bank line at large acute angles, results in flow concentration along bank lines, which creates large forces on bank material or bank protection. As part of studies conducted to determine the required riprap size for impinged flow, velocities were measured on the Snake River near Jackson, Wyoming. High velocities and steep water-surface slopes were observed at each impingement site.