Near-Surface Wind-Induced Mixing in a Mine Lake

Abstract

Wind sheltering can have a strong effect in small, sheltered water bodies; wind-induced mixing in the surface layer of a small mine lake has been investigated using field measurements. Wind speed was recorded at three locations and data suggested sheltering by topography and surface roughness changes with both fetch and the land–water transition. Wind sheltering effects in the near-surface waters were assessed using turbulent microstructure profiler measurements, providing an estimate of the sheltering distance consistent with the literature on “backward-facing” steps. A numerical simulation of the annual density stratification cycle was then performed, using the model DYRESM. Simulations indicated that inclusion of a sheltering algorithm based on the results of the field campaign significantly improved the model’s performance in capturing the surface mixed layer deepening associated with strong wind events.