31B - CUP - 1901 NORTH FAIRVIEW ST

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City of Santa Ana Environmental Checklist Although the project site has been mapped by the CDMG as an area of liquefaction hazard, the project - specific Geotechnical Exploration Report classifies the project site as having a low risk of liquefaction based on the liquefaction potential index. The liquefaction potential index combines depth, thickness, and factor of safety of liquefiable material inferred from a cone penetrometer test sounding into a single parameter. The liquefaction potential index for the project site ranges from 1 to 2.5. Liquefaction potential index values lower than five are deemed low risk The potential for liquefaction at the project site is generally confined within thin layers at depths ranging from about 20 to 50 feet bgs (Appendix B). Between one and two inches of liquefaction- induced settlement is expected to take place in relatively thin layers at depths generally greater than 20 feet bgs. Seismically induced settlement at the project site is expected to be between 1 to 2 inches. Seismically induced differential settlement is expected to be half an inch over a horizontal distance of 100 feet. As described above, the proposed project would comply with all CBC requirements and standards related to liquefaction. Additionally, as required in Mitigation Measure GEO -1, the proposed project would comply with all geotechnical recommendations provided in the Geotechnical Exploration Report (Appendix B) to minimize potential impacts related to liquefaction. Therefore, potential impacts related to seismic - related ground failure, including liquefaction are less than significant with implementation of Mitigation Measure GEO -1. a4. Landslides? Less - than - Significant Impact. Landslides and other slope failures are secondary seismic effects that are common during or soon after earthquakes. Areas that are most susceptible to earthquake - induced landslides are steep slopes underlain by loose, weak soils, and areas on or adjacent to existing landslide deposits. As discussed in Vl.a1, the proposed project site is located in a seismically active region subject to strong ground shaking. However, according to the CDMG Seismic Hazards Zone Map for the Anaheim Quadrangle, the project site is not located within or adjacent to an earthquake- induced landslide area. The project site is located in a generally flat developed urban area that does not contain large slopes, and development of the project would not generate large slopes on the project site. As a result, implementation of the proposed project would not expose people or structures to substantial adverse effects involving landslides. Impacts are considered less than significant. b. Result in substantial soil erosion or the loss of topsoil? Less - than - Significant Impact Construction of the proposed project would include ground surface disruption that could result in soil erosion. During Phase 1, rough grading and site trenching and building foundation excavation would take place on approximately 312,945 square feet, and fine grading and soil preparation would take place on approximately 220,588 square feet. During Phase 11, site trenching and building foundation excavation would take place on approximately 83,050 square feet and fine grading and soil preparation would take place on approximately 30,450 square feet. Construction activities would expose areas of soil to wind and water erosion, and during a storm event, exposed soils could be transported off the site as runoff. Because the project would disturb over 1 acre of land, the proposed project is subject to the SWRCB General Construction Permit. Compliance with the General Construction Permit requires the development and implementation of a Storm Water Pollution Prevention Plan ( SWPPP). The SWPPP requires identification of sources of sediment and a list of BMPs to provide sediment and erosion The Academy Charter High School 3 39 tune 2012 Initial Study /Mitigated Negative Declaration ItF 0091412 31 B -115