12 ATTACHMENT 6 - Laserfiche WebLink

EXHIBIT H MEMORANDUM date: 6 February 2014 pages: 1 name: company: email: Kevin Ebrahimi SummerHill Homes kebrahimi @shhomes.com from: Joshua M. Roper, PE, LEED AP subject: 5850 West Las Positas Boulevard—Pleasanton,California Southern Property Line Noise Barrier CSA project number: 13-0602 As requested,this memo discusses specific acoustic concerns for the planned six-foot tall noise barrier along the southern property line of the residential project at 5850 Las Positas Boulevard in Pleasanton. The barrier will separate the project site from the adjacent Arroyo Mocho Canal, as well as the existing single-family residences beyond. An environmental noise assessment was prepared for the project and is summarized in a report dated 12 December 2013. For reference,a 3-decibel change in environmental noise is generally considered a just-perceivable difference.. Consider the following: • Barrier Height: You have asked whether increasing the barrier height from six to eight feet would provide a practical benefit in shielding the existing residences across the canal from on-site activity.The project indudes a vehide circulation path and parking in the southern portion of the site. Increasing the barrier height would reduce vehicle noise by approximately 1 to 2 decibels, which would not be distinguishable at the existing residences. • Barrier Reflections:You have asked if noise from roadways and the sports fields south of existing residences(across the canal)will be reflected back to those residences. - Based on our visit to the site and review of aerial images of the neighborhood, one to five rows of homes generally separate Parkside Drive and the sports fields from the project site. Reflected noise would be both shielded by the homes and attenuated by the added distance of the canal. The estimated potential increase in noise level, due to wall reflections, is 2 decibels or less,which would not be distinguishable. - An exception to the shielding is at the end of Harvey Court,where there is a line-of-sight between the project site (barrier location)and both the roadway and sports fields.The estimated potential increase in average noise levels from vehicles along Parkside Drive and occupants moving around the sports field is not expected to noticeably increase at the residences. Acoustics - The project will include planted vines along the barrier, which will grow over top and help to Audiovisual scatter noise on the canal side,thereby reducing focused reflections to the existing residences. Telecommunications Security Please call with any questions. 100W.San Fernando Suite 430 Son Jose,CA 95113 T 408.295.4944 F 408.295.4949 www.crosalter.com mss., Charles M. Salter ASSOCIATES INC.