Item 18 - Appeal Application Nos. 2023-02 and 2023-03 for Cabrillo Town Center project

Home Browse Search

Following the proper design guidelines and construction measures outlined in the CBC and as required by Mitigation Measure MM-OZ 4.5-1 would reduce this risk to a less -than -significant level. Liquefaction The Certified EIR stated that the Overlay Zone is located in a low potential liquefaction hazard area as identified in the City's Seismic Safety Element of the General Plan. Despite being in a low hazard area for liquefaction, the City requires compliance with the CBC and all provisions related to construction and design guidelines which prevent injury or other adverse effects potentially caused by liquefaction. Among the provisions of the CBC that would be implemented by the Overlay Zone would be the conformance of all proposed facilities at the project site to the seismic - resistant design standards designated for Seismic Zone 4, and the incorporation of additional seismic -resistant earthwork and construction design criteria as recommended by project -specific geotechnical reports with implementation of Mitigation Measure MM-OZ 4.5-1. Adherence by the proposed development structures to CBC guidelines and geotechnical reports would ensure that proper foundations would be designed to safeguard against the potential risks associated with liquefaction. This impact was determined to be less than significant. Erosion/Loss of Topsoil The Certified EIR state that topsoil is the uppermost layer of soil, usually the top 6 to 8 inches. It has the highest concentration of organic matter and microorganisms and is where most biological soil activity occurs. Plants generally concentrate their roots in, and obtain most of their nutrients from, this layer. Topsoil erosion is of concern when the topsoil layer is blown or washed away, which makes plant life or agricultural production impossible. Much of the Overlay Zone is built out and topsoil erosion is, thus, not an issue for the majority of the area. However, there are limited undeveloped areas that could be affected by loss of topsoil if developed. Future development under the Overlay Zone could involve the demolition of existing structures, followed by grading and excavation activities prior to the construction of new development. The uncovered on -site soil would be exposed to erosional processes during these phases of construction. However, operational activities such as the addition of paved and landscaped areas would, over the long term, decrease the potential for erosion, particularly on the existing limited undeveloped sites, because less exposed soil would exist in the Overlay Zone. Specific erosion impacts would depend largely on the areas affected and the length of time soils are subject to conditions that would be affected by erosion processes. All demolition and construction activities within the City would be required to comply with CBC Chapter 70 standards, which would ensure implementation of appropriate measures during grading activities to reduce soil erosion. In addition, all construction activities would comply with Chapter 33 of the CBC, which regulates excavation activities and the construction of foundations, and Chapter 33 of the CBC, which regulates grading activities, including drainage and erosion control. Cabrillo Town Center City of Santa Ana Technical Memorandum August 2023 City Council 18 — 534 10/3/2023