Agenda - 09-04-2014 - 6a - Laserfiche WebLink

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40 1 locations are not scattered across the field as shown here, but rather are concentrated in 3 2 locations. So, this is the inverter transformer nearest to Cascade Drive, and there are 2 others 3 located here and here. I want to note that this is not a single inverter. This is a station 4 consisting —excuse me a 15 kilowatt station —wait let me think about that— 1500 kilowatt 5 station rather than a 500 kilowatt station. So it's 3 of these 68 decibel producing units together. 6 In addition, there is apparently a transformer associated with this, and transformers in 7 themselves produce noise. So it's really very difficult to determine the total noise that's going to 8 be produced from this unit, since we don't exactly know what the unit is comprised of. However, 9 I attempted to calculate the noise from 3 separate 68 decibel sources, which is apparently what 10 this includes without considering the additional noise that could be produced by a transformer. 11 So I found the formula to do this on the web, and there is actually a place where you can plug in 12 the numbers. I double checked the numbers by hand to make sure that they were correct, and 13 instead of 68 decibels for this unit, it produces 77.54 decibels. That does not include any 14 transformer noise. How much louder is 77.54 decibels? Well it's not a linear scale, so it's 15 roughly 10 times, a little less than 10 times the sound pressure and twice the perceived 16 loudness of 68 decibels. I then used the same methodology that the applicants used in their 17 proposal here, in which they estimated the noise at different distances from the source. And 18 you can see if you do it in meters it's a little bit easier because it's whole numbers, but a meter 19 is about 3.3 feet. That with each doubling of distance from the source, the sound level drops by 20 6 decibels, and you can see this goes down by 6 decibels with every doubling of distance from 21 the source. I then measured the distance from the inverter on Cascade Drive to my property 22 line and got a different figure from Mr. Wallace. Using the scale on the site plan, I determined 23 that the distance from the inverter on Cascade Drive to my property line was 104 feet 24 approximately, as best as I could determine using that method. At that distance the sound level 25 at my property line would be 47.54 decibels. So how loud is 47.54 decibels compared to the 26 ambient sound on my property? I didn't have time to get a calibrated sound meter, but I did 27 download an app that most people agree, at least online, is a fairly good and fairly accurate tool. 28 We went out to our side yard at the property line near the development. The development 29 would be on this side. This is Cascade Drive here. This is Falls coming in. That's my wife 30 holding the meter, and that's the sign for the hearing. And this is what I saw. I did this a couple 31 of times at different times of the day. We have about a 32 decibel background. I just want to 32 point out that these little blips that you see is birdsong. So how much difference is 32 decibels 33 from 47 decibels? Well it's 15 decibels and the perceived difference in sound levels is different 34 from the decibel number, but for every 10 decibels there is roughly a doubling in perceived 35 sound —the psycho acoustic sort of thing. So this means that the sound in my property 36 boundary will apparently go up by about 3 fold at the property line. So, what I submit to you 37 then is that the applicant's noise level data incorrectly states the locations and the types and the 38 combined noise levels of the inverter transformers at the Binks site. It also emits the contribution 39 of the step up transformer on the Cascade side; so we don't really know how much noise this 40 thing is going to produce. 41 42 At our property boundary there will be a continuous 47.5 decibel or greater inverter 43 drone during the sunny days that will be perceived as being at least 3 times louder than the 44 current ambient rural sounds. And since the applicants didn't base their laboratory noise 45 analysis on triple inverter units and apparently did not factor in transformer noise, the noise 46 levels could be even higher. I submit to you that the applicants' noise impact assessment is 47 faulty as a result of using false assumptions about the types, configurations and locations of the 48 inverter/transformer units; and that the applicants should be required to submit sound level 49 testing data for the actual that they are going to install at the site and have proposed to use and 50 then estimate the noise impacts from their true locations as depicted in the site plan. Thank 51 you.