The spreading of suspended matter formed during construction works of offshore wind farms

Offshore Wind Farms play a significant role in ensuring Europe's energy security. In Poland, a significant increase in the  number  of  newly-constructed  wind turbines  has  been  observed  in  recent  years. Wind power is "clean", but not completely free of environmental impacts. Their impact on the environment is difficult to assess. The impact of dredging works on suspended matter created during construction works will be presented  based on numerical model results. A model has been built based on MIKE, tools supplied by the Danish Hydraulic Institute (DHI) and the Weather Research and Forecasting model (WRF)- mesoscale numerical weather prediction system. Based on the numerical model created, analysis of the temporal and spatial variability of the spreading suspension generated from dredging works carried out during construction works aimed at positioning the wind turbines in appropriate places.

The advective-diffusive character of transported matter is the most natural clean, their direction, turbulent viscosity and sedimentation rate. Authors evaluated that during the construction phase, concentration of the suspended sediment will exceed 10 mg/l, which is denerous value for cod larvae, for short time (no longer than 48 hours) and will cover small area. The deposition will be irrelevant, the largest rate will occur in the immediate vicinity of the construction works and it will decrease with the distance. The range of the transferable suspension will not exceed 15 km. Cumulative factors significantly increase the concentration of the suspension (in a critical case they may even double it). They may occur when simultaneous actions are taken to prepare the foundation for more than one wind turbine at the same time, which is rather technical impossible because there is not a lot of special purpose sea vessel that are able to work on construction of basements of the offshore wind generators.