Scientific data presented by Dr. Paul Cryan in 2008 to the Wind Turbine Guidelines Advisory Committee and in the Journal of Wildlife Management provides evidence that bats are killed by wind turbines due to the mating behavior of bats seeking the highest tree.
The bats regard the wind turbines as the highest trees as they view the landscape during mating season. The bats are subsequently killed during their ascent by the wind turbine blades. The bats are killed by being struck by the blades and also by barotrauma, caused by the drop in atmospheric pressure at the blade tips which damages the bats’ lungs.
The Timbermill permit application provides a list of wind turbines that might be used, with the rotor diameter ranging from approximately 413 to 449 feet and a rotation speed of 15 rotations per minute. At 15 rotations per minute, using a rotor diameter of 449 feet, times 15 rotations times 60 (minutes/hour), divided by 5,280 (the number of feet per mile), the tip speed would be approximately 240 miles per hour. Applying scientific data to the stated Timbermill Wind facility in Chowan and Perquimans counties, provided in the applications to the counties, the bat fatalities would be as much as 9,000 per year.
Scientific data pertaining to the aquifers underlying Chowan, Perquimans, and Pasquotank counties shows the surficial aquifer and underlying confined Yorktown and Castle Hayne aquifers currently supply Chowan County and the surficial aquifer and underlying confined Yorktown aquifer supply Perquimans County. The hydraulic head of each aquifer provides the force to prevent saltwater intrusion. Excessive pumping results in less hydraulic head.
In an ENRSoutheast news article, Iberdrola’s vice president of construction for the wind facility being constructed in Pasquotank County explained that during construction of the 67-foot diameter concrete wind turbine foundations, extending to 12 feet deep, that numerous wells were placed around the turbine foundation perimeter in order to pump the groundwater down to 15 to 20 feet below the bottom of the 12-foot deep foundation excavation area.
Personnel from the N.C. Department of Environmental Protection agreed that this constituted a lot of water being pumped; however, they stated that this is considered part of the construction activities and that there is no regulatory requirement regarding the removal of such large quantities of groundwater.
Such pumping will reduce the hydraulic head of the surficial and inter-connected Yorktown aquifers to facilitate greater saltwater intrusion. Scientific research, therefore, exposes negative impacts by windmills to bats and to aquifers underlying Chowan, Perquimans, and Pasquotank counties.
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