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Home My WebLink AboutEIR 93-02; Green Valley; Environmental Impact Report (EIR) (50).......... . ..... .... .. .... -. -. .. .. .I Endo Ewineering ' T~ufic Engineering Ait. Quality Sfudim Noise A.ssessments -_ : .. .." ... ,. '. I_. t: ~ .. 26,1993 Ms.. Sarah Madstn -1 .. ........ ... ..*- .. ~. ... .... % "-Col&man Plannhg Gmup ",. ,.. .. .... . I10 Esconddo Avmue, Suite 207 : ViskCA 92084 .. .. ... - : .... .... ..... .. ___... Subject: Potential Noise Impacts on Biologically Sensitive Areas .. .... - .. _. .. .I .... \ Dear Ms. Madsen; . Endo Engineering is currently evaluating the noise impacts associated with the Green Valley project on the biologically sensitive areas in tots I, 2, 3, 8, and 10. The primary noise source, is El Camino Real, which has an existing volume of approximately 18,000 The project biologist has indicated that the significant noise level that will impact the Least Bells Vircos is a daytime peak hour noise level of 60 Ley, Based upon noise modeling, must of the open $ace in Lots 1,2, and 3 are currently impacted by noise Ievds which ex- 60 Leq, With future tdfic volumes almost tripling, the noise levels adjacenc to El Ca.tnho Real will exceed the biologically significant noise level (60 Leq) throughout the entire OPCR space area of Lots 1, 2, and 3. In addition, there is the potential for noise hp&ts OII Lots3 md 10. Thm arc two sound attenuation factors which are typically utilized by noise srudies. A sound attenuation factor of 3.0 ds per doubling of distance is typically assumed for hard site conditions, or situations where the linc-of-sight between receptor and source generdly exceeds 3 mttrs above the ground. A sound attenuation factor of 4.5 dB per doubling of dis:encp: is appropriate for soft sites with mitior obs~rlc~ons. Sound attenuation factors as high as 6,O dB pw doubing of distance have been measured at other project sites. The projected noise level as a result of El Carnino Real at Lots 8 and IO could be characterized by a variety of sound attenuarion factors, Overall, the project site would be typically characterized as a soft site, and would not be expected to have noise impacts on Lots 8 and 10. However, ortions of Lots 8 and 10 me elevated with respect to the noise modeling assumes a noise attenuation factor of 3.0 dB per doubling of distance, the 6p Leq contour couId extend over 2,500 feet from El Camino Real and intrude upon biologically sensitive atas in Lots 8 and 10. .. - .I . .- . . ADT and a future pr0jCcte.d volume of appmxisnatcly 50,000 ADT. ?. P inmcning terrain, and the P ine-of-sight may exceed 3 meters above ground level. If the .-. 21797 hke Forest Drive, Suite 204, El Tor.!), Ca/(fimia 92530-2758 (714) 768-4333 FAX 768-0718 A more detailed noise analysis would need to be based up noise measurements ad'acent to the biologically sensitive areas on-site, and is beyond OUT cmnt scope of work. based upan our current level of understanding, the noise report wiU cancludo that Lots 1,2, and 3 will be fully impacted under future conditions, and that there 81y= potential noise impacts along portions of bts 8 and 10 under future cmdtions. Sincerely, ENDOENGXN'EERING ,- 6'4.