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Potentially • Significant • Potentially Unless Less than • Significant Mitigation Significant Impact Incorporated Impact No Impact g. Changes in deposition'or erosion of beach,sands,or changes in siltations, X • deposition or erosion which may modify the channel of a river or stream or the bed or the ocean or any bay,inlet or lake? Comments: a) i. The Alquist-Priolo Earthquake Fault Zoning Act requires the delineation of zones along suffidently active and well- defined faults by the California Department of Conservation,Geological Survey(CGS). The project site is not within an Earthquake Fault Zone, as defined by the Alquist-Priolo Earthquake Fault Zoning Act, and no known active or potentially active faults exist on the site. The nearest active fault to the project is the Hayward fault, approximately 2.9 miles to the northeast; the Calaveras, approximately 17 miles to the northeast; and the San Andreas, approximately 26 miles to the southwest. Therefore no fault rupture hazards are anticipated with the project. ii, Iii. In 2002, the U.S. Geologic Survey (USGS) predicted a 62 percent probability of a magnitude 6.7 or greater earthquake occurring in the San Francisco Bay Area by the year 2032. During a major earthquake on a segment of one of the nearby faults, strong shaking is expected to occur at the project site. The project site is also within a designated liquefaction hazard zone. Strong shaking during an earthquake can result in ground failure such as that associated with soil liquefaction, lateral spreading and cyclic densification. Test borings and cone penetration tests were performed on site by Rockridge Geotechnical In August, 2008, and in October 2013 and these results were used to evaluate the potential for seismic hazards to occur. Based on preliminary field investigations, potentially significant impacts could occur with geologic hazards associated with strong shaking on a nearby fault and the presence of compressible clay zones below the site. Therefore, mitigation of potential liquefaction hazards is required with project implementation. Mitigation Measure#5: The City of San Leandro has incorporated the 2012 International Building Code into its municipal building code(Title 7, Chapter 7-5). The project applicant would be required to comply with all applicable State and City regulations to address potential geologic hazards associated with the proposed project, Including ground shaking and liquefaction. Geotechnical and seismic design criteria must conform to engineering recommendations in accordance with the seismic requirements of the 2013 San Leandro • Building Code. Additionally, because the project site is in a liquefaction Seismic Hazard Zone, the project applicant will be required to comply with the guidelines set forth by California Geological Survey Special Publication 117. Implementation of Mitigation Measure#5 reduces potential Impacts to a less than significant level. iv. The TOD Strategy Area is nearly flat, and there are no hilly areas immediately adjacent to the project site. The site consists of four undeveloped parcels with elevations ranging between 45 and 49 feet. The site is underlain by alluvium consisting of interbedded clay,sand and gravel. The site is not associated with significant slopes,and there are no adjacent hillsides. Therefore, the proposed project would not create potential Impacts associated with landslides,mudfows or other mass soil movements. b) The proposed project would require grading activities that could create effects on water quality as a result of erosion. Because the project site exceeds one acre in size, the project applicant would be required to apply for coverage under the State General Construction Permit In order to comply with federal National Pollutant Discharge Elimination System (NPDES) requirements, in accordance with the State Water Resources Control Board (see Section VIII, Hydrology and Water Quality). The applicant would be required to develop and implement a Storm Water Prevention Plan (SWPPP) to reduce potential erosion and subsequent sedimentation of storm water runoff. The SWPPP would include Best Management Practices (BMPs)to control erosion associated with grading,trenching and other ground surface disturbance. Additionally,all construction activities will be required to comply with Chapter 18 of the San Leandro Municipal Code regulating excavation activities and the construction of foundations and retaining walls,as well as the San Leandro Grading Ordinance regulating grading activities,drainage and erosion control. Therefore, compliance with the NPDES permit process and the California Building Code requirements would minimize potential impacts from erosion during and after project construction and would ensure that potential geology and soils impacts are less than significant. c-e)Two samples of near surface soil were analyzed that showed that the soil is classified as"moderately corrosive to • corrosive". Soft,weak and easily disturbed soil may be encountered during the excavation of the site. An acceptable degree of soil stability would be achieved for expansive, liquefaction-prone and compressible soils by incorporating soil treatment programs such as replacement, grouting, compaction and drainage control during the excavation and construction phases of the project in order to address site-specific soil conditions. No septic tanks or leach field systems are proposed as part of the project, but rather wastewater disposal would be handled through the sanitary sewer system. • 9 •