Yuan, S.; Li, L.; Amini, F., and Tang, H., 2015. Sensitivity of combined turbulent wave overtopping and storm surge overflow response to variations in levee geometry.Overtopping of earthen levees produces fast-flowing, turbulent water velocities on the land-side slope that can damage the protective grass covering and expose the underlying soil to erosion. High-performance turf reinforcement mat (HPTRM) is one of the most advanced flexible armoring technologies for severe erosion challenges. Response to combined wave overtopping and storm surge overflow of an HPTRM-strengthened levee was studied in a three-dimension full-scale numerical flume. Little information is known about the role of levee geometry in the performance of an HPTRM-strengthened levee during turbulent overtopping conditions. The goal of this study was to investigate the sensitivity of combined wave overtopping and storm surge overflow response to variations in levee geometry. This is important since the geometry directly impacts the levee performance and levee design. Four conceptual models of different-morphology levees with different significant wave heights were simulated. The models included a total of 25 different combined overtopping cases with various hydrodynamic conditions. The impacts of crest widths, land-side and sea-side slopes, and an additional mild berm on the overtopping discharge, turbulent bottom shear stress, turbulent kinetic energy, and erosion rate at the toe of land-side slope were investigated. New empirical equations based on these structural parameters were developed.