Turbulence Measurement of Combined Wave and Surge Overtopping of a Full-Scale HPTRM-Strengthened Levee

Abstract

A combination of storm surge and extreme waves may cause overtopping of coastal protection structures such as levees, dikes, and seawalls, resulting in structural damage and flooding behind these structures. High turbulence of the overtopping flow is an important or even critical factor in soil erosion, and may be responsible for the destruction of levees during combined overtopping. The goal of this study was to observe and measure the turbulence on the crest and landside of levees strengthened by high performance turf reinforcement mats (HPTRMs). A full-scale laboratory study of the combined wave and surge overtopping of a levee strengthened with HPTRMs was conducted in a two-dimensional (2D) laboratory wave/flow flume. During a total of 11 trials, the authors recorded and processed three-dimensional (3D) velocity and water depth. They developed a new formula to estimate the average overtopping discharge. This paper presents turbulent fluctuations of the three components of flow velocity on the crest and landside slope, and develops formulas to estimate the turbulent intensity. The study used five methods—the log profile method, three turbulent methods (Reynolds stress; turbulent kinetic energy,