Measuring background noise with an attended, mobile survey during nights with stable atmospheric conditions

In response to sound studies from commercial wind developers, a series of background noise surveys were conducted in Cape Vincent, NY between May and July 2008. The survey approach included sampling at night under stable atmospheric conditions and systematically selecting monitoring stations at 1.6 km intervals. Stable conditions occurred in 67% of nights and in 30% of those nights, wind velocities represented worse-case conditions where ground level winds were less than 2 m/s and hub-height winds were greater than wind turbine cut-in speed, 4 m/s. The median A-weighted L90a,9hr sound pressure level was 25.7 and 26.7 dBA. C-weighted SPLs from the two mobile surveys were 40.0 dBC and 43.9 dBC. Assuming 45 dBA background noise, developers of the St. Lawrence Wind Farm predicted noise impacts would not exceed local and New York guidelines. However, assuming worse-case conditions using 25.6 dBA background noise, nearly all residences within range of the St Lawrence Wind Farm exceeded New York guidelines and more than half would have noise levels considered "objectionable" to "intolerable".

This paper was presented at the Inter-Noise 2009 conference held in Ottawa, Canada, August 22 and 23, 2009. Access the full paper by clicking on the link at the bottom of this page.

Schneider Inter Noise2009 Cape Vincent Ambient Noise

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AUG 23 2009
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