AgdaPkt 2017-01-09 Closed and Joint

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c) Be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off-site landslide, lateral spreading, subsidence, liquefaction, or collapse? d) Be located on expansive soil, as defined in Table 18-1-B of the Uniform Building Code, creating substantial risks to life or property? e) Have soils incapable of adequately supporting the use of septic tanks or alternative wastewater disposal systems where sewers are not available for the disposal of wastewater? TA. - Page 64 Summary of Impacts Potentially Less than Significant Less than Significant With Mitigation Significant No Impact Incorporated Impact Impact X X Conclusion: Regarding geology and soils, the proposed project would not result in any new significant environmental impacts or a substantial increase in the severity of previously identified significant impacts (CEQA Guidelines Section 15162(a)). All impacts are adequately evaluated in the certified Downtown Precise Plan program EIR. The proposed project is also consistent with the Downtown Precise Plan (CEQA Guidelines Section 15183). Documentation: a. i) The Downtown Precise Plan project area is located within the seismically active San Francisco Bay Area. The significant earthquakes that occur in the Bay Area are generally associated with crustal movement along well- defined, active fault zones of the San Andreas Fault system, which trends in a northwesterly direction. The project site is located approximately five miles northeast of the San Andreas Fault. Two other major active faults in the area are the Hayward Fault, located about 14 miles northeast of the project site, and the San Gregorio -Seal Cove Fault, located about 13 miles to the west. (DTPP program EIR p. 16-1) The project site is not within an Alquist-Priolo Earthquake Fault Zone (DTPP program EIR p. 16-1); therefore, there is no known potential for fault rupture on the site. ii) and (iii) The project site lies in a seismically active region and is subject to ground shaking from an earthquake along major active regional faults. This is common to virtually all development in the San Francisco Bay Area. Development on the site would be subject to review and approval by the City, and shall be designed and constructed in accordance with all applicable seismic standards adopted by the City of Redwood City, including the California Building Code (CBC), which requires that a site-specific geotechnical investigation be conducted and report prepared by a licensed professional. The site-specific geotechnical report must provide measures to reduce potentially significant geologic hazards (e.g., expansive and corrosive soils, differential settlement, and slope instability). The geotechnical report is subject to City Building Ojjicial approval prior to the issuance of grading and building permits. (DTPP program EIR p. 16-4) The required contents of the geotechnical report are described in DTPP program EIR Mitigation 16-1 and on EIR page 16-6. Techniques and standards for effective geotechnical practices are widely known and accepted. Individual measures for particular sites and projects are typically specified at a detailed level of design. The City routinely requires such geotechnical/geologic investigations and specifications, and a significant record exists demonstrating the effectiveness of such design and engineering requirements in adequately addressing potential soil and geologic issues. Under the City's grading permit and building permit regulations, an individual development project cannot be given final approval without project compliance with geotechnical/geologic requirements. These requirements and related City inspection and verification procedures before project occupancy provide reasonable assurances that the project will incorporate the design and engineering refinements necessary. A site-specific geotechnical report for the proposed project was prepared (Geotechnical Exploration, 603 Jefferson Avenue, Redwood City, California; ENGEO Incorporated; September 3, 2015). The report provides preliminary conclusions and recommendations regarding the following specific geotechnical issues: ■ site seismicity and seismic hazards, including the potential for liquefaction and liquefaction -induced ground failure (liquefaction occurs when loose, saturated soil loses strength and stiffness due to earthquake -induced ground shaking or another stress) ■ groundwater depth ■ estimates offoundation settlement ■ expansive soils and undocumented fills ■ corrosivity 17 *4