3_Exhibit C_ADDENDUM ONLY - Laserfiche WebLink

City of Pleasanton—Stoneridge Mall Residential Project CEQA Checklist Section 15183 Checklist/15164 Addendum 98 FirstCarbon Solutions Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480017/Consistency Checklist/21480017 Stoneridge Mall Residential Project Checklist Addendum_Updated.docx significant, and no mitigation is necessary, consistent with the Prior EIR. There are no proposed changes, new circumstances, or new information that would cause new or more severe impacts. Therefore, there are no environmental effects that are peculiar to the proposed project or the parcels on which the proposed project would be located. Impacts would be less than significant and the proposed project would not result in a new or more severe adverse impact that was not previously identified in the Prior EIR. iii) Ground Failure Prior EIR Conclusions The Prior EIR estimated that much of Pleasanton, including the Housing Element’s potential sites for rezoning, are susceptible to liquefaction. However, it was determined that impacts would be reduced to a less than significant level with implementation of standard seismic structural design standards contained in Chapters 16, and 18 of the CBC. Additionally, it was concluded that grading requirements under Chapter 18 of the CBC would ensure that the maximum practicable protection available from ground failure under static or dynamic conditions for structures and their associated trenches, temporary slopes and foundations would be provided to future construction on the Housing Element’s rezoning sites. It was determined that areas located within Seismic Hazard Zones for liquefaction would also be required to adhere to the requirements of Special Publication 117 in accordance with the Seismic Hazards Mapping Act. The General Plan Public Safety Element, Goal 2, Policy 5, further provides strategies for reducing the risk from ground failure. Therefore, the Prior EIR found that the Housing Element would have a less than significant impact on people and structures related to seismic ground shaking or related ground failure. Analysis of Proposed Project Historically, ground surface displacements closely follow the trace of geologically young faults. The 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. According to the Geotechnical Engineering Report provided by Terracon, the project site is mapped for moderate potential liquefaction hazard by ABAG (Appendix E).46 However, the majority of the soil underlying the site is sufficiently dense and/or cohesive to resist liquefaction, made up of clayey sand to clay material.47 As such, the geological engineering report indicates that the soil overlaying the groundwater is sufficiently thick and cohesive, and the groundwater table sufficiently deep, such that the potential for the subsurface manifestations of liquefaction is low with total settlement expected from liquefaction to be less than 0.5 inch.48 There is a possibility that liquefiable soils are present below the maximum depth of exploration of 61.5 feet performed by Terracon. However, Terra con concluded that, even if liquefiable soils are present below this depth, the thick non-liquefiable layer of soils would mitigate any impacts.49 46 Terracon Consultants. 2014. Geotechnical Engineering Report–1 Stoneridge Mall Road. October 13. 47 Ibid. 48 Ibid. 49 Terracon Consultants. 2014. Geotechnical Engineering Report–1 Stoneridge Mall Road. October 13.