75B - PH ADOPT RESO FOR PR NO 15-6827

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L S A FAIRVIEW BRIDGE REPLACEMENT AND STREET IMPROVEMENTS (9TH STREET TO 16TH STREET( PROJECT INITIAL STUDY/MITIGATED NEGATIVE DECLARATION SANTA ANAL CALIFORNIA MAY 2020 c. Would the project be located on a geologic unit or soil that is unstable, or that would become unstable as a result of the project, and potentially result in on- or off -site landslide, lateral spreading, subsidence, liquefaction or collapse? Less Than Significant Impact. As discussed above in Response 3.7.2(a)(iii) and Response 3.7.2(a)(iv), liquefaction is not anticipated to be a concern, and the Project site is not located within an earthquake -induced -landslide area. The proposed Project would not introduce any new topographical features or elements that would change the existing geologic setting of the Project area. The proposed Project is located in a seismically active region; however the Project area is an existing roadway and the majority of the area is paved. As such, on -site geologic and soils issues such as on -site soil stability including landslides, lateral spreading, subsidence, liquefaction, and collapse are not significant due to the nature of the Project. Therefore, implementation of the proposed Project would not result in impacts associated with unstable geologic conditions. Impacts related to geologic unit stability that could result in lateral spreading, subsidence, liquefaction, or collapse would be less than significant. No mitigation is required. d. Would the project be located on expansive soil, as defined in Table 18-1-8 of the Uniform Building Code (1994), creating substantial direct or indirect risks to life or property? Less Than Significant Impact. Expansive soils generally have a substantial amount of clay particles, which can give up water (shrink) or absorb water (swell) in response to dry and moist conditions and can result in cracking and structural failure of pavement and foundations. The extent or range of the shrink/swell is influenced by the amount and kind of clay present in the soil. The occurrence of these soils is often associated with geologic units having marginal stability. Soils comprised of sand and gravel are not expansive soils. The soils within the Project area consist of alternating, interbedded layers of sand with varying fines content, lean clay with varying amounts of sand, and few silt layers.16 The deeper sand layers include trace to moderate amounts of fine to coarse gravel." As soils within the Project area consist of sand, lean clay with sand, and silt layers, the proposed Project is not expected to create substantial risks to life or property due to expansive soils. In addition, the Project area is an existing roadway and the majority of the area is paved. Therefore, the Project would not create substantial risks to life or property due to expansive soils. Impacts would be less than significant and no mitigation is required. e. Would the project have soils incapable of adequately supporting the use of septic tanks or alternative waste water disposal systems where sewers are not available for the disposal of waste water? No Impact. The proposed Project is an improvement to the existing roadway and does not include the construction of, or connections to, a septic or alternative wastewater disposal system. Therefore, the proposed Project would not result in impacts related to the soil's capability to adequately support the use of septic tanks or alternative wastewater disposal systems, and no impacts would occur. No mitigation is required. 16 Earth Mechanics, Inc. 2018. op. cit. 11 Ibid. 3-42 7 5(11VdS�i261ND\Final ISMND\Fairview Street Bridge Final ISMND.docx (OS/26/2O)