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J standards for stationary sources(see Table 4.13-4).Future noise levels associated with commercial and industrial operations at this site could potentially exceed the MHMP's maximum allowable exterior noise standards at noise-sensitive receptors proposed to the north on the project site.In addition, increases in single-event noise levels, such as backup alarms from material delivery trucks, occurring during noise-sensitive evening and nighttime hours, could result in increased levels of disturbance and sleep disruption to occupants of nearby residential dwellings.Although the proposed Central Parkway that would divide the two land uses would act as a buffer of at least 60 feet,the intensity of the noise levels generated could still adversely affect nearby residences. Mitigation Measure 4.13-4: Noise—Compatibility of Proposed Land Uses exceeding Predicted Noise Levels. The College Park developers shall implement the following measures: ► Traffic Noise—Arterials.Before occupancy of the first residence proposed under the College Park project along each of the seven arterial segments identified in Table 4.13-11, a sound barrier shall be constructed by the College Park developers along that arterial segment.The noise barrier may consist of a wall,berm, or combination thereof.The exact location,height and character of the sound barrier shall be determined by a noise consultant approved by the County.The sound barrier shall reduce outdoor noise levels at the center of backyards of proposed adjacent single-family residences to below 65 dBA L&/CNEL and as close to 60 dBA Ld./CNEL as feasible.This mitigation shall be funded through fair-share payments by the College Park developers. Traffic Noise—I-205.The County shall conduct annual acoustical monitoring at the southernmost sites of the proposed residential,community park,community college buildings/common area, and limited industrial uses. The monitoring shall include 24-hour measurements at the affected properties.At such time as the monitoring indicates that freeway noise levels at the above residential,community park,community college,and limited industrial sites are greater than the applicable noise thresholds(65 dBA CNEL for residential and park uses,70 dBA CNEL for college uses,and 75 dBA CNEL for limited industrial uses),a noise barrier shall be constructed along the north side of I-205 by the College Park developers to protect the affected receptor(s).The required location,height,and character of the noise barrier shall be determined by a noise consultant hired by the County. This mitigation shall be funded through fair-share payments by the College Park developers. Sound barriers could be constructed to protect the proposed land uses from future freeway noise levels. For instance, a sound wall 12 feet high located approximately 50 feet from the edge of I-205 would reduce freeway noise exposure at the south property line of the proposed Delta College site to 69.8 dBA CNEL, which is below the significance threshold of 70 dBA L,,/CNEL for this land use type.This level would also be less than the significance threshold of 75 dBA Ld/CNEL for the proposed industrial/business park.A 12- foot sound wall would also reduce freeway noise exposure at the nearest proposed residences to 61.2 dBA Ld./CNEL,not accounting for additional attenuation provided by the intervening presence of the _ industriallbusiness park. Because preliminary modeling indicates that a sound wall of reasonable height would reduce freeway noise exposure at each land use type below the respected significance threshold,this impact would be less than significant. Agricultural Activity,Industrial,and Commercial Noise.Before the approval of building permits for each individual subdivision, SJCCDD shall evaluate the building permits for compliance with the San Joaquin County Development Title. Where individual projects do not clearly comply with interior noise standards included in these guidelines,mitigation measures such as use of dual-pane windows,mechanical air systems, exterior wall insulation, and other noise-reducing building materials and methods shall be required as appropriate to reduce interior noise exposure to 45 dBA L&(Table 4.13-3).Where individual projects do not — clearly comply with exterior noise standards of the San Joaquin Development Title(Table 4.13-3),mitigation measures, such as use of noise barriers,buildings for screening, and setbacks between noise sources and receptors, shall be implemented as appropriate to minimize exterior noise levels.Where there is a question — regarding pre-mitigation or post-mitigation noise levels in an area, site-specific noise studies may be EDAW College Park at Mountain House Specffic Plan III Draft EIR — Noise 4.13-30 San Joaquin County