SFPUC 2001 Alameda Watershed Management Plan

III. ENVIRONMENTAL SETTING AND IMPACTSL. NOISE1.0 SETTING1.1 NOISE ENVIRONMENTThe Alameda Watershed is mostly undeveloped and has a quiet noise environment typical ofrural areas. However, portions of the Watershed are subject to higher noise levels due tocommercial and industrial development. Primary sources of noise on the Watershed are adjacentroadways and commercial and industrial development within the Watershed, including:! I-680, which traverses the northern portion of the Alameda Watershed;! SR 84, also known as Niles Canyon Road (west of I-680) and Vallecitos Road (east ofI-680), which extends along the northern Alameda Watershed boundary;! Calaveras Road, which extends through the entire Alameda Watershed in a north-southdirection;! Commercial nurseries located east of the Town of Sunol, along SR 84 and Calaveras Road;and! Two major gravel quarries, Mission Valley Rock and RMC Pacific Materials, locatedsouth of I-680.The Alameda County East County Area Plan (Area Plan) (Alameda County, 1993) indicates that1990 noise levels exceeded 75 dBA (CNEL) 1 within approximately 190 feet of I-680 and 65 dBA(CNEL) within 90 feet of SR 84 (Vallecitos Road). By 2010, noise levels are projected toexceed 75 dBA (CNEL) within approximately 230 feet of I-680 and 65 dBA (CNEL) within 213feet of SR 84.The Area Plan identifies as noise sources only those mining operations located generally betweenPleasanton and Livermore. These operations occur in or near urbanized areas and have drawnnoise complaints from nearby residents. The quarries south of I-680 are outside of urbanizedareas; although there are noise-sensitive receptors present in the vicinity, these quarries are notidentified as noise sources in the Area Plan.Other minor sources of noise within the Watershed include operation of SFPUC water storageand distribution facilities; maintenance activities associated with existing SFPUC facilities andother utilities (e.g., Chevron’s high-pressure petroleum pipeline); and recreational uses includingthe Sunol Valley Golf Club and existing trails.1 CNEL, Community Noise Equivalent Level, represents a cumulative measure in decibels (dBA) of communitynoise during a 24-hour period. It applies weighting factors to account for people’s lower tolerance to noise duringthe evening (7 p.m. to 10 p.m.) and night (10 p.m. to 7 a.m.).NOP 96.223E: Alameda Watershed Management Plan III.L-1 ESA / 930385January 2001