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<br />. _, _ _ ~ _._. ".' _.. . ... _ "",--_, _ . _ .v -___ -_ ~~. <br />~~--:'~~:"":"'":.~ ~:_..-;.~...._...-.t:.:,_.~".~,:;--... ;'.' ~",;-.'~' .~__ _~:.~-'S...'., <br /> <br />~-..,;'" .,......'" <br /> <br />1 <br /> <br />Significant noise impacts occur when: <br />· Noise levels increase by 2: 3 decibels (dBA); <br />· Noise levels exceed state standards. <br /> <br />! <br />I <br /> <br />There are two descriptors for state noise standards: <br />· L I 0 - the 90th percentile, in which noise .levels are exceeded 10 percent of the <br />time. <br />· L50 - the 50th percentile, in which noise levels are exceeded 50 percent of the <br />time. <br /> <br />-1 <br />] <br /> <br />Minnesota noise standards are listed by time of day and land use in the following <br />table. <br /> <br />Minnesota Noise Standards <br /> <br /> Daytime 7 a.m.-10 p.m. Nightime 10 p.m.-7 a.m. <br />Land use LIO (dBA) LSO (dBA) LIO (dBA) LSO (dBA) <br />Residential 65 60 55 50 <br />Commercial 70 65 70 65 <br />Industrial 80 75 80 75 <br /> <br />Noise impacts from construction of the. development may exceed the state noise <br />standards for a limited period of time. Every effort will be made to reduce <br />construction noise by ensuring that all equipment has proper noise reduction <br />devices. In addition, construction activities will occur only during daytime hours. <br /> <br />According to the MPCA, noise monitoring, is recommended, although not required: <br />· To establish baseline levels and indicate if a noise problem already exists. <br />· To calibrate the noise analysis model, thereby lending greater reliability to its <br />estimates. <br /> <br />Noise monitoring was conducted at the intersections of County Road C and <br />Cleveland and County Road D and Cleveland on December 29, 2000. Although <br />residential areas are located significantly far from the intersection of Cleveland and <br />County Road C, residences are located in the southeast quadrant of Cleveland and <br />County Road D. Refer to the following table for noise monitoring results. The <br />noise monitoring was done using an Ametek Model Mark 3 Audio Dosimeter. <br /> <br />1 <br />j <br /> <br />It can be seen from the results of the noise monitoring (see table below) that current <br />traffic noise levels currently exceed the Minnesota Residential noise standards at <br />County Road D and Cleveland. It is anticipated that a significant portion of the <br />noise levels observed are attributable to traffic on Interstate 35W immediately west <br />of the development. <br /> <br />Page 28 <br />