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HomeMy WebLinkAboutCT 93-09; Ocean Bluff; Tentative Map (CT) (95)JAMES C. BERRY - ACOUSTICIAN 24O1 Trace Road Spring Valley, CA 91978-1928 Tel/Fax: (619) 66O-OO64 May 21995 Reference: 9321.95A Jack Henthorn and Associates 5431 Avenida Encinas, Suite G Carlsbad, CA 92OO8 Dear Sirs: Reference: Ocean Bluff I have reviewed the latest site plan showing the new location for the sound wall at the rear of the easement for the trail. It is noted that the structural setback is 5O feet from the edge of the right-of-way. I re-calculated the noise reduction afforded by the new situation for the lots directly fronting Poinsettia Lane. I used previously obtained road elevation values and used the pad elevations from the revised plan. In each case, the observer was assumed to be standing at the 5O foot setback location with his feet at oad level. The new situation turns out to be very good for noise reduction. The grade elevation differences, the sound wall and the setback distance combine to provide significant noise mitigation. All residences along Poinsettia Lane should have noise levels at BO dB(A] CNEL/Ldn or below, making their backyards suitable for recreational areas without further mitigation. A summary of the noise level calculations is shown on the attached Table 1. Please call if you have any questions. Yours sincerely, James C. Berry Acoustician MAY 0 3 1995 James C. Berry - Acoustician Tel/Fax (619) 66O-OO64 Reference 9321.95A Table 1 TABLE 1 - Noise Levels at Properties in the Ocean Bluff Development along Poinsettia Lane (Configuration as on May 1 1995) Lot No. 78 79 BO 81 82 83 84 86 Attenuation of Sound Wall dB(A) 15 14 14 14 14 12 12 9 Noise Level at Structural Setback dB(A) CNEL/Ldn 54 55 55 55 55 57 57 BO MAY 0 3 1995