LT3 #1 #2 #3 #4 #5 #6 Figure 3: Location of Long Term measurement site LT3 in the western region of the project area along with numbers assigned to each residence considered minute increments over the course of the measurements. At the time the sound level meters were installed, the wind was gusting to about 2.5 to 5 m/s and most WTG’s in the vicinity of the sites were operating. Similar conditions were observed when the meters were removed on Tuesday, the 17th. Measurements at the LT1 site were at a location about 1000 feet to the west of Azevedo Road and 0.85 miles south of SR 12 near Residence #18 (Figure 4). The hourly noise level data for the measurement period is presented in Figure 5. The Leq levels for the three full days of testing in the 24-hour periods beginning at midnight produced CNEL 11 Residence #18 values of 48 to 49 dBA. This range Figure 4: Location of LT1 near falls below these measured for other Residence # 18 wind energy projects which had ranged from 56 to 74 CNEL. This is likely due to two different of noise. This location is setback from Azevedo Road which is larger than it 85 LT1 has been in the previous long term 80 noise measurements. This location is 75 also somewhat protected from the 70 prevailing wind by the As a result, the trends in the L potential sources 65 L 60 90 Leq to the noisewind levels speed bear measured little resemblance at the 55 nearby met tower at a height of 10m 50 (Figure 6). This lack of correlation is L( 1) further demonstrated with the data are 45 cross-plotted where no consistent Sound40 Pressure Level, dBA increase in noise level is noted with 35 L(10) increased wind speed (Figure 7). As local terrain. 30 25 L(25) 12:00 50 and 15:00 discussed in the appendices 1of8:0 0previous reports L(50) exposed to the prevailingFigure 5: winds.Noise11/13 21 Levels :00 Figure measured 7 also at indicates LT1 for Novemberthat the average 13, 2009 Lthrough November 17 0:00 measured to be about 40 dBA while the L3:00 These data also give some evidence of in 6:00 L(90) factor in the daytime noise levels. 9:00 12:00 11/14 15:00 18 :00 2 1:00 0:00 3:00 6:00 9:00 12:00 Time of Day 11/15 15:00 18:00 21:00 0:00 3:00 6:00 9:00 12:00 8,9 15:00 90 11/ 16 background, thisnoise is wasatypical about of 1 sitesto 2 dBthat18:00 less. are more fluence of SR 12 which may be the limiting21 :00 0:00 3:00 6:00 9:00 11/17 12:00 12 50 was 55 50 45 40 35 30 25 Wind Speed 20 15 10 L(90) Wind 5Speed, m/s & Sound Pressure Level. dBA 0 L(50) 12:00 15 :00 18:00 Figure 6: L 21:00 11/ 13 over the measurement0:0 0period (10 minute intervals) 3:00 80 6:00 9:00 12: 00 50 15:00 and L 11 /14 70 18 :00 21:00 90 0:00 60 noise levels at LT13:00 plotted with wind speed data 6:00 9:00 12:00 Time of Day 50 15: 00 11/15 18 :00 21 :00 40 0:00 3:00 6:00 L(50) Sound Pressure Level, dBA 9:00 30 12:00 15:0 0 11/16 18:00 20 21 :00 0:00 0 1 2 3 4 5 6 7 8 9 10 11 12 13 3:00 The second long-term 6:00 9:00 Road about ¾ mile west of the intersection 12:0 0 Figure 7: L 11 /17 15:00 Residence #20 (Figurethe 8).measurement The period (10 minute intervals) location, the only option available at the time sound level meter to a utility pole very close the L noise on Birds Landing Road. This can be90 noiseinferred levels from at LT1 the plottedL versus wind speed data over y = 0.16x + 39.32 eq levels used in the CNEL calculation are m R 2 easurement location = 0.01 Wind Speed, m/s noise data for LT2 are presen at LT2 was located along Montezuma Hills with Emigh Road and immediately west of the measurements began was to secure the to Montezuma Hills road dominated by the intermittent vehicular 13 ted in Figure 9. At this . For this reason, 1 data (noise level LT2 exceeded 1% of the tim Figure 8: Location of LT1 near often 30 to 40 dB gr Residence # 20 L means90 , thereL are quite short duration events occurring, but with high noise 50 level. Given ,the or evengeneral L noise 85 Residence #20 environment in the Birds Landing 80 area and close proximity of the measurement location to the road, eater than either 75 e these are undoubtedly due to 25 ) which is 70 individual vehicl levels. This 65 reach typically 80 to 60 Leq at this distance. Even though these 55 events are of short duration, their levels are sufficiently high relative to 50 L( 1) the background levels that the energy 45 average (L e passbys which Sound40 Pressure Level, dBA period is governed by these isolated L(10) 35 events. As a result, the CNEL 85 dBA or more 30 values, which range from about 58 to L(25) 25 eq ) level for the time 12:00 15:00 L(50) 63 dBA at this measurement18:0 0 location, are microphone to the Figureroad. At9: fartherNoise11/13 21 Levels: 00distances measured fr at LT2 for November 13, 2009 through November 17 0:00 be reduced. To obtain a noise level estima3:00 te at a distance representative of nearby L(90) Residence #18 which is offset from the ro 6:00 can be assumed corresponding 9:00 12:00 location. The estimated CNEL values would th 11/14 15:00 November 16 18 :00 2 1:00 0:00 3:00 6:00 9:00 12:00 th Time of Day 11/15 15:00 , elevated background noise levels 18:00 21:00 0:00 3:00 6:00 9:00 to two doublings of distan elevated due the close proximity12:00 of the 15:00 11/ 16 om the road, the level of these events18:00 will ad by approximately 50 ft, a 12 dB reduction21 :00 0:00 3:00 6:00 9:00 11/17 en be in the range of 46 to 51 dBA. On 12:00 14 occurred between 3 and 6 am as ces from the microphone indicated by the L90 and L50 levels. On the morning of the following day, these higher levels did not occur although elevated levels did occur after 10 am. The cause could not be determined, however, they are not related to wind speed measured at the met tower in this region of the project (Figure 10). Similar to site LT1, LT2 displayed no correlation to wind speed, however, this was location also quite sheltered from the prevailing winds. In comparison to LT1, the L90 levels are lower on average by about 5 dB at LT2. This maybe due to decreased influence of SR 12 on the background noise levels at this 65 Wind Speed L(90) L(50) 60 55 50 45 40 35 30 25 20 15 10 Wind Speed, m/s & Sound Pressure Level. dBA Level. Pressure Sound m/s & Speed, Wind 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 :00 00 :00 :0 :0 00 :00 :0 :0 :0 :0 :00 00 :0 :0 1: 0:0 0 3 6: 00 9 5 8: 0 3:0 0 6 9:00 2 5:0 8:0 0 1:0 0:0 0 3 6: 00 9 5: 1:0 0:0 0 3 6:0 9 12 15:0018:002 12:001 1 21:00 1 1 1 2 12 1 18:0 2 12:0015:00 11/13 11 /14 11/ 15 11/16 11/ 17 Time of Day Figure 10: L 50 and L90 noise levels at LT2 plotted with wind speed data over the measurement period (10 minute intervals) location which was both further away from the highway and more shielded by LT3 hills in that direction. As was the case for LT2, the sound level meter at the third long-term measurement location was alongside Honker Bay Road on a utility pole just west of Residence #1 (Figure 11). This location was about ½ mile west of Olson Road and about 475 yards south of SR 12. Existing WTG’s were in the vicinity of this location, one line starting approximately ½ mile to the northwest, and another line Residence #1 approximately 0.8 miles to the southwest. The noise data at this site (Figure 12) only indicated the influence Figure 11: Location of LT3 near of local traffic events on Honker Bay Residence # 1 Road (similar to LT2) during a few 15 85 80 75 70 65 60 Leq 55 50 L( 1) 45 Sound40 Pressure Level, dBA 35 L(10) 30 25 L(25) 15:00 18:00 21 :00 L(50) tim 11/13 0:00 3:00 L e intervals duringFigure the 12:m Noise Levels measured at LT2 for November 13, 2009 higher90 than either LT1 or LT2 6:00 and through Lthrough November 17 9:00 L(90) calculated from the hourly L 12:00 range of values measured previously in the Montezuma15: 00Hills region.