RES 06035 - Laserfiche WebLink

Chapter 4 Environmental Setting, Impacts, and Mitigation Measures J. Noise In Pleasanton, the General Plan (1996) defines "normally acceptable," "conditionally accept- able," and "unacceptable" noise conditions for different land uses (see Appendix E, Table E3). Noise impact analysis practice is to consider project-generated noise level increases of 3 Ldn or greater significant where exterior noise levels would exceed the normally acceptable noise level standard (60 Ldn for noise sensitive uses). Where noise levels would remain below the normally acceptable noise level standard with the project, noise level increases of 5 Ldn or greater would be considered significant. c. Impacts (1) Noise and Land Use Compatibility Environmental Issues Compatibility standards for some of the types of uses potentially included in the Phase II Specific Plan have been established by the Pleasanton General Plan: . Education and child-care facilities would be considered to be "normally acceptable" in noise environments not exceeding 60 dBA Ldn; . Outdoor sports and recreation, neighborhood parks, and playgrounds would be considered "normally acceptable" in noise environments not exceeding 65 dBA Ldn; . Agricultural areas would be considered "normally acceptable" in noise environments not exceeding 70 dBA Ldn. . Open space areas, trails, and wetlands are not covered under the land use compatibility standards. An Ldn of 70 dBA would be appropriate in areas intended to serve as buffers for noise propagation, if they also include human use areas. With the development of the project, some noise sensitive uses would be exposed to noise levels in excess of those considered compatible by the Pleasanton General Plan. 1.680 Eastern Exposure. Areas east of 1-680 are in direct line-of-sight to the roadway and experience high traffic noise levels, even where deep setbacks are provided. In unshielded areas, 1-680 was measured to generate a noise level of 80 dBA Ldn at a distance of about 165 feet from the centerline of the roadway (about 30 feet from the edge of pavement) and a noise level of about 67 dBA Ldn at a distance of about 800 feet from the center of the road- way. Land uses proposed for the adjacent areas (sub-areas 6, 7, and 10) include agriculture, wetlands, and open space. Shielding provided by terrain (such as the berm located along the western side of the roadway) and/or structures (such as the ones proposed as part of Phase I to shield the now existing single-family homes in the northern portion of the Plan area along Bernal Avenue) would substantially reduce these noise levels. A berm would not be effective to reduce noise levels along the Laguna Creek Lane/UPRR Overpass, where 1-680 is elevated. Without additional noise reduction measures, noise levels would be expected to exceed 70 dBA Ldn at distances of 500 feet or less from the 105