Observation and Parameterization of Bottom Shear Stress and Sediment Resuspension in a Large Shallow Lake

Parameterizations for bottom shear stress are required to predict sediment resuspension from field observations and within numerical models that do not resolve flow the viscous sublayer. This study assessed three observation-based (τb) parameterizations, including (a) sum of surface wave mean current (quadratic) (); (b) log-law (τb = τL); (c) turbulent kinetic energy τTKE); using 2 years a large shallow lake. For this system, parameterization τb τw + τc was sufficient qualitatively resuspension, since currents orbitals were two major processes found resuspend sediments. However, τL τTKE parameterizations also captured development nepheloid layer hypolimnion associated with high-frequency internal waves. Reynolds-averaged Navier-Stokes (RANS) equation parameterize as summation modeled current-induced (τc,m) wave-induced (τw,m). The performance different τw,m τc,m in RANS against observations. optimal yielded root-mean-square errors 0.031 0.025 Pa, respectively, when τw,m, set constant canonical drag coefficient. A RANS-based developed; however, grid-averaged dissipation did always match local observations, leading O(10) prediction stress. Turbulence-based should be further developed application flows shear-free boundary turbulence.