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<br />Rick Riehm on Trail Bike Area Noise Assessment <br />29 July 2005 <br />Page 2 <br /> <br />Continuously reading meters were also set up at two locations, the Neal Brueggemeier residence <br />north of the trail area and the Paul Segner residences west of the trail area. Due to some technical <br />problems, data from the Brueggemeier location were not"reliable. However, data from the Segner <br />residence and the nine monitoring sites provided sufficient information.for estimating sound <br />levels at more remote locations. <br /> <br />The time history ofth.e LIO and L50 sound levels at the Segner residence is shown on <br />Attachment 2. L50 is the level observed 50% of the time during each minute shown on the <br />chart. Also shown (ar]:>itrarily at the 42 dBA level) are the times that bikes were using the trail. <br />The very high LI 0 level are associated with passing vehicles and no.t related to the trail. It can be <br />seen that there is some correlation with activity on the trail, with maximum LI0 levels generally' <br />around 46 dBA with some peaks at 48 dBA. Sound levels with bike activity increased generally <br />no more than 6 dBA during the course of the test. <br /> <br />. Estimated Sound Levels at Surrounding Residential Recentor Sites <br /> <br />Sound levels from thetrail were projected to each of 13 surrounding residential locations <br />assuming attenuation with distance and atmospheric absorption, but limited attenuation from any <br />topography or vegetation. Therefore, sound levels could be lower under calm conditions, lower <br />with wind blowing towards the trail and higher with the wind blowing from. the trail. :L 10 levels <br />have been predicted for 3,6, 12 and 24 bikes using the trail continuously for an hour. The 13 <br />receptors, approximate distance from the center trail area, and predicted LI 0 levels for 3 and 6 <br />bikes are shown in the table below. Location of the receptor sites is shown on Attachment!. <br /> <br />Site Resident ApD. Dist (ft) L1 0 (3 bikes) LID (6 bikes) <br />1 Unknown 2900 44 47 <br />2 1289 Jennings Ave. NW 1600 49 52 <br />... Ted LeelRichard Riehm 2200 47 50 <br />:J <br />4 Paul Segner 2500 46 49 <br />5 Jeff Schober 2000 48 51 <br />6 Unoccupied 1- 2500 46 49 <br /> -. <br />7 Neal Brueggemeier 1900 48 51 <br />8 Harvev Engelman 2200 50 53 <br />9 Ted Lorentz 3100 44 47 <br />10 (Albion) 3300 44 47 <br />11 . Mike Horsch 3300 47 50 <br />12 . David Bowman 3700 46 49 , <br />13 (planned home) 1200 53 56 <br /> LI 0 Standard 65 65 <br /> <br />The results for 3,6, 12 and 24 bikes shown graphicaUy on Attachment 3, although use of the <br />track by the higher number of bikes will be limited. The general range of observed background <br />sound level in the area is also shown on the attachment. <br /> <br />Based upon the monitored noise levels and predictions based upon these levels, use of the trail <br />bike area is not expected to generate sound levels over the Minnesota daytime noise standards. <br /> <br />y:\jobs\2005j obs\205064\ri ehm-on 9-mem. doc <br /> <br />18 <br />