3D hydrodynamic modeling of Lake Zurich

A three-dimensional hydrodynamic Z-model was conceived for Lake Zurich (Switzerland, ZH) using the modeling software Delft3D. Calibration was performed on the thermal profile in 2017 at three monitoring stations located in both basins, and was validated on years 2015 and 2016 with the same method. The model reproduced effectively thermal stratification and water temperature’s spatial and temporal variability. Specific hydrodynamic events were correctly simulated: upwellings were detected but their amplitude was underestimated; seiches periods were found accordingly to values reported in the literature. Hypolimneon’s temperature was nicely reproduced but results were less accurate in the epilimneon and especially in the metalimneon. Flow velocities were qualitatively evaluated and exhibited realistic values; the model was able to reproduce clockwise and counterclockwise flow rotation motions. Suggested improvements imply collecting more data about rivers, the importance of the latter on Obersee dynamics having been demonstrated, and the focus on wind drag coefficients in the calibration process.