Modeling wind-induced currents in lake Bolmen, Sweden, using TELEMAC 2D

Abstract: Transport and material intermixing within lake systems have a significant impact on lake water quality. However, since researchers are primarily concerned with biological, environmental, and ecological aspects, physics and hydrodynamic behavior in lake water currents frequently receive less attention. The results of several wind-induced current circulation scenarios in Lake Bolmen with its complicated bathymetry are presented. The significance of various physical parameters influencing the circulation pattern owing to wind force acting on the lake, as well as the prediction of how physical changes can modify the circulation pattern, were explored. Herein a two-dimensional mathematical model for Bolmen Lake in Sweden was analyzed by TELEMAC-MASCARET Software. QGIS and Blue Kenue software were used to processing and visualize the data and results. Simulation conducted for steady winds, stratified water condition, and actual wind data. Wind intensity and direction affect the lake's ultimate hydrodynamic circulation. In steady-state simulations, stable circulation vector graphs displaying water current movements were achieved after two days. The tracer was included in a lake model to assess the effects of instantaneous solute transmission via advection and diffusion processes. Tracer time-series graphs and velocity maps were also employed to understand the mixing process within the lake. Vorticity patterns of the velocity field and the tracer analysis were the key indicators used to identify the hydrodynamic circulation governed by wind force. Vorticity patterns and magnitude of velocity fields change within the lake area and were distinguished with the changing wind direction and magnitude. In each simulation clear patterns observed distinguishable from the rest of the simulations carried out. Also, noticeable tracer detection times were observed in each simulation. Stratification seems to have minimal impact on water currents and their characteristics. The study can be further improved by accommodating three-dimensional modeling, water inflow and outflow to the lake, and calibrating with water level data.