Agenda - Council - 06/13/2017 - Laserfiche WebLink

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All modeled nighttime impacts are within the NAC-2 standards. Therefore, assuming the proposed residences will have year-round climate control, the modeled impacts at the proposed development are within the State noise standards and no additional mitigation is required. V. Railroad Noise Impacts Based on the noise monitoring data collected during train pass-bys, the trains are not generally expected to cause exceedances of the State Noise standards. Analysis of time history data for the train pass-bys show that the full length trains cause elevated noise levels (above 64.5 dBA) for about 90 to 110 seconds. Without, the proposed berm, it would take four or more full length trains passing by in an hour to approach the 6 minutes of impact required for the Lio exceedances. One to three full length trains passed by per hour during the monitoring. This is consistent with MnDOT rail traffic information for this track. Therefore, train noise is not likely to cause the Minnesota noise standards to be exceeded in a way that requires additional mitigation. VI. Summary and Conclusions Riverstone Development, LLC is proposing a residential development in Ramsey, Minnesota. The proposed project location is bordered on the south by Minnesota Highway 10 (TH 10) and a Burlington Northern railroad track. The proposed project location and layout is shown in Figure 1. Because of the potential noise impacts from TH 10 traffic , the City of Ramsey as requested a noise study to evaluate the proposed project relative to Minnesota Noise Standards. The project is proposing a berm between the residential area and the highway and railroad. Post -development noise levels were predicted for 19 receptor locations using monitoring data and computer modeling The modeled noise level at one of the 19 receptor locations exceeds the Minnesota NAC-1 standards for daytime hours. The modeled noise level at all but one of the receptor locations exceeds the Minnesota NAC-1 standards for nighttime hours. The NAC-1 daytime standards are designed to prevent speech interference in areas for outdoor activities. Areas for outdoor activities are not allowed if these noise levels are exceeded. The modeled L50 noise level at Receptor R1A exceeds the State standard by just 0.4 dBA. Remedies could include 1) having no areas for outdoor use in the portion of the property facing the roadway, 2)a barrier (solid fence) around all or a portion of the yard or patio at this home blocking the line of site between the vehicles on the road and an area designated for outdoor use or, 3) extending the proposed berm to provide additional mitigation at this location. The nighttime NAC-1 standards are designed to prevent sleep interference for people sleeping in bedrooms with partially open windows. NAC-2 nighttime standards apply to NAC-1 locations if the building is constructed in such a way that the exterior to interior sound level attenuation is at least 30 dBA and the building has year-round climate control. Buildings meeting the State building code requirements typically meet the 30 dBA exterior to interior sound level attenuation requirement.