8.1 SR 08-15-2022 - Laserfiche WebLink

Home Browse Search

Mr. Steve Pullar May 27, 2022 Elk River Sportsman's Club Noise Measurements Page 3 The maximum allowable noise level is defined in the Shooting Range Protection Act as being an Leq(h) level (an hourly Leq3) that is the MPCA L10 level minus 2 dBA. In the case of this development, since the shooting range is only in use during the daytime hours, the MPCA daytime L10 level is 65 dBA for residential receivers. Therefore, the maximum hourly shooting range allowable hourly noise level is 63 dBA for residential properties. If it is determined that any hourly level during the noise monitoring (while the gun club is in use) exceeds the requirements, the statute states that mitigation needs to be provided. Mitigation options usually include physical barriers (like berms, walls, fences, or buildings to block line of sight and reduce noise) and increased distance from the noise source. Outdoor Noise Monitoring Results Through discussions with you (about your conversations with the City of Elk River), it was determined that two site visits would be performed, to measure noise during two heavy-use gun shooting periods: one measurement period for noise from the trap shooting area and the other for noise from the 600-yard rifle range. These shooting areas are shown in Figure 2 below, along with the noise measurement locations. Mr. Andrew Schmitt of ESI Engineering visited the property during the following times to measure the gun noise while actively monitoring the noise occurring, noting the sources, taking weather data, and making other general observations: • Monday, May 16t", 2022, from 3:30 PM to 7:OOPM to measure noise from the 600-yard rifle range (measurement location #1 on Figure 2; photo of ineasurement setup shown in Figure 3) • Wednesday, May 18t", 2022, from 1 1:30 AM to 2:OOPM to measure noise from the trap shooting area (measurement location #2 on Figure 2; photo of ineasurement setup shown in Figure 4) The measurement locations at the residential development were chosen because they were nearest the rifle range and trap area. The noise measurement system collected sound data continuously for at least 2 hours at each location while guns were being fired. The noise measurement data from the 600-yard range period is provided in Attachment A and the data from the trap shooting period is provided in Attachment B. Noise equipment calibration records are included in Attachment C. 3 Leq is the equivalent continuous sound level, which is defined as the steady sound pressure level which, over a given period of time, has the same total energy as the actual fluctuating noise. Leq is the preferred method to describe sound levels that vary over time, resulting in a single decibel value.