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(g) BENDER READY-MIX CONCRETE MANUFACTURING PROJECT Initial Study/Mitigated Negative Declaration 1 3) Seismic-related ground failure, including liquefaction? 1 Less Than Significant Impact With Mitigation Incorporated. Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. Liquefaction is characterized by a loss of shear strength in the affected soil layers, thereby causing the soils to behave as a viscous liquid. Susceptibility to liquefaction is based on geologic and geotechnical data. River channels and floodplains are considered most susceptible to liquefaction, while alluvial fans have a lower susceptibility. Depth to groundwater is another important element in the susceptibility to liquefaction. Groundwater shallower than 30 feet results in high to very high susceptibility to liquefaction, while deeper water results in low and very low susceptibility. Based upon the Seismic Hazard Element of the City's General Plan, the project site is subject to the potential for liquefaction. Given the minor nature of improvements associated with the project, it is not expected that any liquefaction-related hazards would occur. Moreover, the existing structures on-site have not sustained damage due to liquefaction since their construction in 1965. In addition, as stated above, the improvements associated with the project would be designed and constructed in accordance with CBC requirements to minimize any impacts related to seismically- induced liquefaction (refer to Mitigation Measure GEO-1). Thus, impacts in this regard are considered less than significant. Mitigation Measures: Refer to Mitigation Measure GEO-1. No additional mitigation is required. 4) Landslides? No Impact Landslides are a serious geologic hazard, with some moving slowly and causing damage gradually, and others moving rapidly and causing unexpected damage. Gravity is the force driving landslide movement. Factors that commonly allow the force of gravity to overcome the resistance of earth material to landslide movement include saturation by water, steepening of slopes by erosion or construction, alternate freezing or thawing, and seismic shaking. The proposed project site and surrounding areas are fully developed and topography is generally flat. There are no landforms within the vicinity capable of producing a landslide. Thus, no impacts would occur in this regard. ' Mitigation Measures: No mitigation is required. b) Result in substantial soil erosion or the loss of topsoil? Less Than Significant Impact With Mitigation Incorporated. Grading and excavation activities associated with the proposed project would expose soils to potential short-term erosion by wind and water. Since the project impact area would be below one acre, the proposed project would not be subject to the requirements of the Construction General Permit under the National Pollutant Discharge Elimination System (NPDES) program administered by the Santa Ana Regional Water Quality Control Board (RWQCB). However, project construction would be required to comply with Chapter 18, Article VII, Water Pollution, of the City's Municipal Code. The Municipal Code includes numerous measures for the control of erosion and urban runoff for both new development and redevelopment. Upon adherence to these requirements, impacts in this regard would be less than significant (refer to Mitigation Measure GEO-2). ri JULY 2011 4.6-3 GEOLOGY AND SOILS 31A-53