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designed to prevent pollutants from contacting stormwater and keep all products of erosion from moving off site
<br /> into receiving waters. Routine inspection of all BMPs is required under the provisions of the Construction General
<br /> Permit, and the SWPPP must be prepared and implemented by qualified individuals as defined by the SWRCB.
<br /> Because land disturbance for Project construction activities would exceed 1 acre, the Project Applicant would be
<br /> required to obtain coverage under the Construction General Permit issued by the SWRCB prior to the start of
<br /> construction within the Project site. Specifically, the Construction General Permit requires that the following be
<br /> kept on site at all times: (i)a copy of the Notice of Intent to Comply with Terms of the General Permit to Discharge
<br /> Water Associated with Construction Activity; (ii) a waste discharge identification number issued by the SWRCB;
<br /> (iii)a SWPPP and Monitoring Program Plan for the construction activity requiring the construction permit; and (iv)
<br /> records of all inspections, compliance and non-compliance reports, evidence of self-inspection, and good
<br /> housekeeping practices.
<br /> The SWPPP requires the construction contractor to implement water quality BMPs to ensure that water quality
<br /> standards are met and that stormwater runoff from the construction work areas do not cause degradation of water
<br /> quality in receiving water bodies. The SWPPP must describe the type, location, and function of stormwater BMPs
<br /> to be implemented, and must demonstrate that the combination of BMPs selected are adequate to meet the
<br /> discharge prohibitions, effluent standards, and receiving water limitations contained in Construction General
<br /> Permit. As such, through compliance with the Construction General Permit, the Project would not adversely affect
<br /> water quality. Therefore, short-term construction impacts associated with water quality would be less than
<br /> significant, and this issue will not be further evaluated in the Draft EIR.
<br /> With respect to Project operation, future uses on site that could contribute pollutants to stormwater runoff in the
<br /> long term include uncovered parking areas (through small fuel and/or fluid leaks), uncovered refuse
<br /> storage/management areas, landscape/open space areas (if pesticides/herbicides and fertilizers are improperly
<br /> applied), and general litter/debris. During storm events, the first few hours of moderate to heavy rainfall could
<br /> wash a majority of pollutants from the paved areas where, without proper stormwater controls and BMPs, those
<br /> pollutants could enter the municipal storm drain system before eventually being discharged to adjacent
<br /> waterways. The majority of pollutants entering the storm drain system in this manner would be dust, litter, and
<br /> possibly residual petroleum products (e.g., motor oil, gasoline, diesel fuel). Certain metals, along with nutrients
<br /> and pesticides from landscape areas, can also be present in stormwater runoff. Between periods of rainfall,
<br /> surface pollutants tend to accumulate, and runoff from the first significant storm of the year("first flush")would
<br /> likely have the largest concentration of pollutants.
<br /> Stormwater quality in San Joaquin County is regulated by the Stormwater Quality Control Criteria Plan
<br /> (SWQCCP), which sets forth standards that apply to all new developments and significant redevelopment projects
<br /> falling under the priority project categories, of which the project site is one. The primary strategy employed by the
<br /> SWQCCP is to require development to manage and treat stormwater flows to the maximum extent practicable to
<br /> control pollutants, pollutant loads, and runoff volume by(1) minimizing the impervious surface area and
<br /> implementing source control measures, (2) controlling runoff from impervious surfaces using structural BMPs
<br /> (e.g., infiltration, bioretention, and/or rainfall harvest and re-use), and (3) ensuring all structural BMPs are
<br /> monitored and maintained for the life of the development. These measures are often referred to as low impact
<br /> development principles.
<br /> As part of the Project, a new engineered stormwater drainage system would be constructed on the Project site to
<br /> collect and treat on-site stormwater. After development, a majority of stormwater from the Project site would drain
<br /> into three below-grade, open, earthen infiltration basins within the north portion of the site. Stormwater flows
<br /> would be conveyed via sheet flows away from buildings, and where possible, through below-grade, landscaped
<br /> areas prior to entering the nearest catch basin and subsequently being conveyed to the three earthen detention
<br /> basins. The landscaped areas would act as the first filter for detaining suspended solids in stormwater flows. The
<br /> detention basins would be planted with native grasses and erosion control vegetation along their side banks.
<br /> Stormwater flows collected by the detention basins would be allowed to infiltrate into the soils, recharging the
<br /> underlying groundwater basin (San Joaquin Valley Basin).
<br /> The Project and its new stormwater drainage system would be sized to capture and treat all on-site stormwater
<br /> generated by two consecutive 10-year, 24-hour storm events, as required by the County of San Joaquin. The
<br /> detention basins would feature an earthen bottom that would allow flows collected by the detention basins to
<br /> infiltrate into the soils and recharge the underlying groundwater basin. On the whole, the project's stormwater
<br /> capture and treatment system would be designed to meet the requirements of the SWQCCP, ensuring that the
<br /> project would not violate water quality standards or waste discharge requirements or otherwise substantially
<br /> degrade surface water or groundwater quality.
<br /> With respect to groundwater quality, the Project would include BMPs that would allow for stormwater to be
<br /> collected and treated in bio-filtration basins to allow for stormwater flows to infiltrate soils and recharge
<br /> groundwater. These structural BMPs would treat stormwater flows prior to infiltration, ensuring that flows
<br /> infiltrating groundwater aquifers do not result in adverse effects to groundwater quality. Moreover,flows entering
<br /> Enter oroiect#s. —Initial Study 23
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