PC 2000-45 - Laserfiche WebLink

Measure Nla. Avoid placement of opaque noise barriers along 1-680; if noise barriers are provided, imploment Measure Nib. Measure Nlb. Plan for noise mitigation in a manner that takes account of the visual consequences of noise barriers on views of the site from the outside and on views from within the project. ~: Specific economic, social, or other considerations make infeasible mitigation measures or project alternatives identified in the Final EIR. Facts in Su~_ tmrt of Findine: The following facts demonstrate that it is not feasible to mitigate the impact to a less than significant level. a. Mitigation Measure Nla is not feasible to mitigate Impact N1 bec~_~ it is not technologically possible to maintain acceptable noise levels on the site without placing noise barriers along 1-680. Instead, the Greenbriar Project implements a set of noise attenuation features that balance noise reduction objectives and the aesthetic effects of noise reduction features, primarily through a combination ofberms and soundwalls. b. Mitigation Measure Nib will be implemented through project design and architectural features such as a landscaped berm/soundwall combination extending along the east and west side ofi-680 for most of site. The berm will be designed with an undulating surface, to approximate the character of a natural land form, It will also be of varying height; where it is lower than the full height needed for noise mitigation, it will be topped by a soundwall, and the soundwall may include panels of transparent material so that the noise barrier would not be opaque along its entire alignment. c. Southbound on 1-680, views into the Project will remain unobstructed both at the northern and southern ends of the property, where the freeway is elevated. Views of Pleasanton Ridge will remain along the entire reach ofi-680. d. On the east side ofi-680, views over the soundberms toward Mt. Diablo will still be available at the south and north ends of the 1-680 frontage, where the freeway is elevated. e. The Greenbriar PUD uses landscaped soundberms, designed to retain views (especially of Pleasanton Ridge) from 1-680, as the principal means of noise attenuation. f. The Greenbriar Project retains key visual resources of the site and provide views of and across the site from Bernal Avenue and 1-680 by the provision of 320 acres of currently unplanned future public uses. These 320 acres have been massed in a manner to maximize potential for future public uses, while maintaining setbacks from major regional and local transportation corridors. 61