Offshore wind farm impacts on surface waves and circulation in Eastern Lake Ontario

• A coupled wave and hydrodynamic model was applied to Lake Ontario.
• An offshore wind farm was simulated by influencing wave transmission and adding drag.
• The wind farm had a very small influence on the overall wave field.
• Flows in the wind farm were locally redirected and had greater spatial variability.

A coupled wave and hydrodynamic model was applied to the Kingston Basin of eastern Lake Ontario, a region with bathymetric variability due to channels and shoals, to assess the potential impacts on surface waves and wind-driven circulation of an offshore wind farm. The model was used to simulate a series of storm events with time-varying wind forcing and validated against wave, current and water level observations. The wind farm was simulated by adding semi-permeable structures in the surface wave model to represent the turbine monopiles, and by adding an energy loss term to the fluid momentum equations in the hydrodynamic model to represent the added drag of the monopiles on the flow. The results suggest that the wind farm would have a small influence on waves and circulation throughout the wind farm area, with spatial variability due to focussing of wave energy and re-direction of the flow. Overall, the results indicate that the wave height in coastal areas will be minimally affected with changes in significant wave height predicted to be < 3%. Larger changes to the strength of circulation occur inside the wind farm region with localized changes in current magnitude of up to 8 cm s− 1. The results of this study may help to understand the impacts of future offshore wind farms and other offshore structures in the Great Lakes.