WIND TURBINE FARMS IMPACT ON POLLEN TRANSPORT DISPERSION PATTER S
Wind energy has become more and more popular because electricity generation by wind power brings much less environmental impacts than conventional energy generation using coal. Also, energy generated by wind power does not require expensive fuel imported from overseas. Since the land in between turbines is still cultivated for crops and grazing, it is important to know the potential interference of wind turbines with pollen transport and dispersion, or the possible change of patterns established for thousands of years. However, these issues have not been studied in the literature. The co-existence of conventional crops with genetically modified (GM) crops has become a subject of debate. In particular, pollen transfer from GM crops to non-GM crops might result in the introgression of transgenes into natural populations as maize is mainly wind-pollinated. This study thus reports and assesses a comprehensive method that estimates maize pollen transport in the presence of turbines to ascertain the potential for maize pollen transport. The study on the concentrations of maize pollen transport affected by the wind turbines considers different dispersion parameters given the additional mechanical turbulence introduced by the presence of operating wind turbines. For instance, the wind turbines can increase surface roughness which subsequently causes increased mechanical turbulence. A high mechanical turbulence subsequently reduces downwind concentrations because of the mixing higher and wider into the atmosphere, which dilutes the maize pollen plume with more clean air. This study compares maize hourly concentrations and ground level flux levels inside and outside a virtual maize flux in the presence and absence of operating wind turbines. Results from a 14-day simulation of maize transport xii with and without operating wind turbines indicate that each difference of corresponding concentration and flux levels is statistically significant. Likewise, patterns of maize pollen transport inside the farm with turbine effects are significantly different from those without turbine effects. Overall, the average maize pollen concentration inside the farm in the absence of turbine effects is about 5 times greater than the corresponding maize pollen concentration with turbine effects. The total mass of maize pollen released into the air is the same whether the wind turbines are present or not. The portion of maize pollen staying inside the farm, on the other hand, is influenced by turbulence. For instance, the increased surface roughness caused by the turbine effects will increase the mechanical turbulence. Because the high mechanical turbulence carries a large portion of maize pollen away from the farm, only a small portion of maize pollen stays inside the farm due to the high turbulence that lifts maize pollen into higher levels of flow where the wind speed is stronger. In contrast, without turbine effects, a small portion of maize pollen leaves the farm while most of it deposits on the ground much sooner than it would with turbine effects. Therefore, maize pollen concentration and ground level flux in the presence of turbine effects will be greater than they are without turbine effects at a relatively far distance from the farm.