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Mr. Steve Jankowski <br />Mr. Brian O lson <br /> <br />April 29, 2002 <br /> Page 3 <br /> <br />%ise Analysis Results- 2nd Addition <br />results are Lu~, A-weighted decibels or dBA) <br /> <br /> tNo Wall Six-Foot Wall Ten-Foot Wall <br />Receptor dBA dBA Reduction dBA Reduction <br /> <br />R- 1 66 66 0 65 1 <br />R-2 64 64 0 64 0 <br />R~3 68 65 3 63 5 <br />R-4 69 67 2 67 2 <br />R.-5 62 61 1 ~' 60 <br />State Daytime 65 65 65 <br />Standard <br /> <br />Minnesota Rules Chapter 7030.0030 (Noise Control Requirement) requires municipalities to take <br />reasonable measures to prevent the establishment of land use where noise standards would be <br />immediately exceeded upon establishment of the land use. Because a relatively short portion of <br />this development is adjacent to TH 47 and it includes an access road that requires a large gap ina <br />potential noise barrier, a noise barrier would have little perceptible effect on noise levels in the <br />development. Based on the lack of effectiveness of the studied barriers noise mitigation is not <br />considered reasonable at this development. Installation of a barrier would provide visual <br />screening from the road and may be reasonable on an aesthetic basis. <br /> <br />Wildlife Sanctuary 3rd Addition <br /> <br />Homes in the 3rd Addition are located more than 300 feet from TH 47 and, therefore, are <br />predicted to experience lower noise levels. Noise levels will range from 57 to 62 dBA, or three <br />to eight dBA below state daytime noise standards. The noticeable effectiveness of noise barriers <br />is typically limited to areas within 300 to 400 feet of a roadway. A six- to ten-foot barrier <br />(placed either in the highway right of way, west of TH 47 or west of the wetland) would reduce <br />noise by only one to three dBA at receptors in this development (a barely' perceptible decrease). <br />Based on these results, noise mitigation would not be effective at the 3rd Addition and is not <br />recommended. <br /> <br />qoise Analysis Results -3rd Addition <br />results are L(o, A-weighted decibels or dBA) <br /> <br /> No Wall Six-Foot Wall Ten-Foot Wall <br />Receptor dBA dBA Reduction dBA Reduction <br /> <br />R-6 62 60 2 59 3 <br />R~7 6l 59 2 58 3 <br />R-8 62 60 2 59 3 <br />R-9 57 57 0 56 1 <br />R~10 59 58 1 58 1 <br />State Daytime 65 65 65 <br />Standard <br /> <br />-t59- <br /> <br /> <br />