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present and the potential for temporary water quality impacts would be negligible; and(3)the use of recycled water is extensively regulated by the RWQCB pursuant to DHS regulations for reliability and quality factors to _. ensure that potential water quality and public health impacts are avoided.The potential short-term impacts associated with the proposed use of treated wastewater are less than significant. IMPACT Water Quality—Potential Temporary Construction-Related Water Quality Effects. Temporary 4.8-1 construction-related disturbances within the College Park site could result in the discharge of contaminated stormwater and non-stormwater discharges to drainage systems and ultimately the Mountain House Creek - channel and Old River.A potentially significant impact would occur. Construction-related ground-disturbing activities within the College Park site would be extensive. Grading, earth moving,excavation and utility installation, infrastructure development,and building construction would disturb the existing vegetative cover, soil,and drainage systems over the entire College Park site.Construction activities can be anticipated periodically in various locations across the project site for several years. During this period, disturbed sites throughout the approximately 1,370-acre area would be subject to exposure to wind, erosion, rain, and winter stormwater runoff.In particular,construction activities could result in substantial soil erosion and stormwater discharges of suspended solids,increased turbidity, and potential mobilization of other pollutants from project construction sites as contaminated runoff or direct discharges to drainage channels.Although the proposed project site topography consists of level or gently-sloping land and the potential for soil erosion is considered low, intense rainfall and associated stormwater runoff could result in short periods of sheet erosion within areas of exposed or stockpiled soils.If this erosion is uncontrolled,the soil materials could cause sedimentation and - blockage of drainage channels. Furthermore,the compaction of soils by heavy equipment may reduce the infiltration capacity of soils and increase the potential for runoff and erosion. Many construction-related wastes have the potential to degrade existing water quality in receiving waters by altering the dissolved oxygen content, temperature,pH,suspended sediment and turbidity levels, or nutrient content or may cause toxic effects in the aquatic environment.Non-stormwater discharges from activities such as y construction dewatering procedures; direct construction disturbances of drainage channels and already-completed stormwater drainage conveyance systems; or accidental spills of hazardous substances, such as fuels, oils, concrete,paints, solvents,cleaners, or other construction materials,also have the potential to degrade water quality.In addition, construction dewatering activities may be necessary for foundation and utility installations if shallow groundwater is present.Potential disposal options for the dewatering discharges include land application with subsequent evaporation and percolation back to the groundwater,use for dust control mitigation practices, or direct discharge to the existing or constructed stormwater drainage channels. Dewatering discharges may contain elevated levels of suspended sediment or other construction-related contaminants, or constituents present in the background groundwater, such as agricultural drainage. Construction activities for the proposed project that are implemented without mitigation could violate water quality standards or cause direct harm to aquatic organisms. Consequently,the potential construction-related water quality impacts are considered potentially significant. _ Mitigation Measure 4.8-1:Water Ouality—Potential Temporary Construction-Related Water Quality Effects The College Park developers shall consult with the Central Valley RWQCB to acquire the appropriate regulatory approvals that may be necessary to obtain Section 401 water quality certification, ensure compliance with the SWRCB statewide NPDES stormwater permit for general construction activity and the Central Valley RWQCB NPDES permit for construction dewatering activity,and obtain any other necessary site-specific WDRs or _ waivers issued pursuant to the Porter-Cologne Act.As required under the NPDES stormwater permit for general construction activity,the project applicant shall prepare a SWPPP and any other necessary engineering plans and specifications for pollution prevention and control.The SWPPP and other appropriate plans shall: EDAW College Park at Mountain House Specific Plan III Draft EIR Water Quality 4.8.14 San Joaquin County