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Environmental Checklist Hydrology and Water Quality Environmental Consistency Checklist Pursuant to CEQA Guidelines Section 15183 73 As described under criterion a and in the General Plan EIR, C.3 provisions would require the project to implement construction phase BMPs and post-construction site design measures and stormwater treatment measures such as the bioretention areas on site to minimize erosion and siltation. In addition, the City requires an Erosion and Sediment Control Plan pursuant to SLMC 7.12.230 which would reduce erosion or siltation impacts on and off of the project site. Therefore, impacts related to erosion and siltation from altered drainage patterns on the project site would be less than significant. c.ii. Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would substantially increase the rate or amount of surface runoff in a manner which would result in flooding on- or off-site? c.iii. Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would create or contribute runoff water which would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff? The proposed project would increase impervious surfaces on the site, which would result in a corresponding increase in surface runoff. Adherence to Provision C.3 requirements in the State Water Resources Control Board’s municipal separate storm sewer systems (MS4) General Permit for redevelopment would ensure the project would not increase runoff relative to existing conditions. The project would include landscaped and bioretention areas, which would not produce an increase in polluted runoff compared to existing uses. In addition, all detention or stormwater treatment facilities would be designed to the City and ACFD’s standards which would ensure the capacity of stormwater drainage systems would be adequate to serve the project site (City of San Leandro 2016b). As stated in Appendix HYDRO, the storm drain system would be designed to meet the City’s requirements. Implementation of General Plan Policy EH-4.1 focused on reducing pollution from urban runoff and Policy EH-4.11 which promotes green infrastructure to improve stormwater quality would further reduce impacts. Overall, the project would not create or contribute runoff water that would exceed the capacity of existing or planned stormwater drainage systems or provide substantial additional sources of polluted runoff that would result in flooding. This impact would be less than significant. c.iv. Would the project substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river or through the addition of impervious surfaces, in a manner which would impede or redirect flood flows? d.Would the project be located in flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation? The project site is located within Zone X, defined as an area of minimal flood hazard as shown in Map number 06001C0259G (FEMA 2009). Therefore, the proposed project would not impede or redirect flood flows, or otherwise adversely affect floodplain management. The project would not increase flood hazards on neighboring properties or otherwise adversely affect floodplain management because grading for the project would not substantially alter the existing site topography. The project site is located outside of a Dam Breach Inundation Area, outside of a tsunami hazard area, and approximately 2.6 miles north of the San Lorenzo Community Center which has a body of