PC-2026-08 - Laserfiche WebLink

City of Pleasanton—Hidden Canyon Residences and Preserve Project CEQA Findings of Fact and Statement of Overriding Considerations FirstCarbon Solutions 35 Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480016/FOF/21480016 Pleasanton Hidden Canyon Residences and Preserve Project FOF.docx xx Evaluating the lateral extent and depth of colluvial soils. x Performing a seismic refraction survey to determine shear wave velocities at deeper depths. x Analyzing and developing slope grading and engineered buttress fill design criteria. x Evaluating upslope sources of water. x Evaluating the Site Classification for Seismic Design. x Estimating appropriate minimum building setbacks from the face of fill slopes. The qualified Geotechnical Engineer would be required to demonstrate that implementation of the recommendations would reduce potential impacts associated with liquefaction and landslide potential to below a level of significance in conformance with the standards in the California Building Standards Code (CBC). The applicant would be required to incorporate all recommended design features into project building plans, for review and approval by the City Engineer prior to the issuance of any building or grading permits. Facts in Support of Findings: Seismic-induced Ground Failure According to the Updated Geotechnical and Geologic Report, the main development area encompassing the 28 proposed single-family homes has low liquefaction potential. (Draft EIR, p. 3.6- 25). However, the northeastern and southeastern portions of the project site have a moderate to high liquefaction potential. (Draft EIR, p. 3.6-26). Therefore, to ensure compliance with General Plan policies and programs, including Program 5.1 and 5.2 requiring the use of site-specific studies or geotechnical engineering studies, the proposed project would implement MM GEO-1. Implementation of MM GEO-1 would involve the hiring of a qualified Geotechnical Engineer to prepare a design-level geotechnical investigation and to provide recommendations that would be incorporated into the design of the proposed project to further reduce impacts related to seismic- induced ground failure such as liquefaction. Through implementation of MM GEO-1, the proposed project would reduce impacts resulting from seismic-induced ground failure to less than significant. Landslides The project site is situated on complex topography with moderately steep to steep hillsides ranging from 774 feet in elevation above mean sea level (AMSL) on the western portion of the project site to approximately 438 feet AMSL along Devany Creek on the eastern portion of the project site. The Updated Geotechnical and Geologic Report concludes that while a majority of natural slopes are relatively stable, proposed cuts during future grading could affect the stability of finished slopes. (Draft EIR, pp. 3.6-26 to 3.6-27). This could result in a potentially significant impact to landslides as a result of strong seismic shaking. To reduce these impacts, and to demonstrate compliance with General Plan Programs 5.1 and 5.2, the proposed project would implement MM GEO-1. Through implementation of MM GEO-1, the proposed project would reduce impacts resulting from seismic- induced landslides to less than significant.