Influence of Three Levee-Strengthening Systems on Overtopping Hydraulic Parameters and Hydraulic Equivalency Analysis between Steady and Intermittent Overtopping

Abstract

Different types of strengthening systems were introduced to protect the crest and land-side slope of the levees against surge overflow and wave overtopping after Hurricane Katrina. Three levee-strengthening systems, roller-compacted concrete, articulated concrete block, and high-performance turf reinforcement mat, were investigated through full-scale laboratory tests in this study. Hydraulic performances of these three levee-strengthening systems were compared to determine the effect of strengthening systems and to provide the equivalency analysis between surge-only overflow and combined wave and surge overtopping. The findings of this study indicate that the high-performance turf reinforcement mat system has the strongest effect in reducing and smoothing the overtopping discharge and in reducing the flow velocity and wavefront velocity on the land-side slope, whereas roller-compacted concrete has the weakest effect. Equivalency analysis between surge-only overflow and combined wave and surge overtopping reveals that the impact of waves on the overtopping discharge and flow velocity on the land-side slope during combined wave and surge overtopping is negligible when the relative freeboard