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INITIAL STUDY/MITIGATED NEGATIVE DECLARATION FAIRVIEw BRIDGE REPLACEMENT AND STREET IMPROVEMENTS A <br />MAY 2020 (9TH STREET TO 16TH STREET) PROJECT <br />J" <br />SANTA ANA. CALIFORNIA <br />pressures, soil grain size, plasticity, relative density, and the confining pressures of the soils in <br />the Project area. <br />As discussed above, the proposed Project does not propose habitable structures and thus would <br />not expose people or structures to potentially substantial adverse effects, including the risk of <br />loss, injury, or death involving seismic -related ground failure (e.g., liquefaction). The original <br />roadway design and proposed Project improvements are subject to California geotechnical <br />standards and regulations (e.g., the CBC) to reduce impacts related to seismic hazards, including <br />liquefaction. Therefore, the proposed Project would result in less -than -significant impacts <br />related to seismic events, including liquefaction. No mitigation is required. <br />iv. Landslides? <br />No Impact. Seismically induced landslides and other slope failures are common occurrences <br />during, or soon after, earthquakes in areas with significant ground slopes. Currently, there are <br />no State -issued seismic hazard zone maps for the City.15 The proposed Project would not <br />introduce any new topographical features or elements that would increase the risk of landslide <br />within the Project vicinity. Therefore, there would be no potential impacts to the proposed <br />Project related to landslides. No mitigation is required. <br />b. Would the project result in substantial soil erosion or the loss of topsoil? <br />Less Than Significant Impact. The Project area is an existing roadway, and the majority of the area is <br />paved. Because the Project area is developed, existing topsoil has already been removed or <br />otherwise disturbed. However, during construction, earthwork and grading activities would disturb <br />and expose soils along the shoulder of Fairview Street. Construction activities are subject to the CBC <br />and would be required to comply with the Construction General Permit (CGP) issued by the State <br />Water Resources Control Board (SWRCB). <br />The National Pollutant Discharge Elimination System (NPDES) program regulates storm water and <br />non -storm water discharges associated with construction or demolition activities including, but not <br />limited to, clearing, grading, grubbing, or excavation, or any other activity that results in a land <br />disturbance equal to or greater than 1 ac. The NPDES program requires the development and <br />implementation of a Storm Water Pollution Prevention Plan (SWPPP), which will prescribe BMPs <br />that the discharger will use to protect storm water runoff and provide erosion control. <br />Implementation of a SWPPP and the BMPs would minimize the impacts related to soil erosion to <br />less -than -significant levels. Compliance with the CGP and the City's Water Quality Ordinance will <br />reduce potential impacts related to erosion and loss of topsoil associated with the proposed project <br />to levels considered less than significant. No mitigation is required. <br />15 California Department of Conservation. 2006. Seismic Hazard Zones. Website: http://maps.conservation. <br />ca.gov/cgs/informationwa rehouse/ (accessed August 2019). <br />R:\WKE1702\ISMND\Final ISMND\Fairview Street Bridge Final ISMND.docx (05/26/20) 3-41 <br />