14 ATTACHMENT 6 - Appendix A - E

City of Pleasanton–Spotorno Ranch Reduced Development Project Initial Study/Consistency Checklist Environmental Checklist FirstCarbon Solutions 101 https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480021/Consistency Checklist/21480021 Spotorno Ranch Consistency Checklist ScreenCheck.docx not result in new or more severe impacts related to unstable geologic units or soils beyond what was previously analyzed in the 1998 HVSP FEIR. d) Expansive Soils Would the project: Be located on expansive soil, creating substantial direct or indirect risks to life or property? According to the 1998 HVSP FEIR, expansive soils on the project site could damage proposed development. However, implementation of specifications for foundation design and construction and the characteristics of subgrade soils provided in the HVSP would mitigate the potential for damage resulting from shrinking and swelling of the soil, consistent with MM H8. The 1998 HVSP FEIR concluded that impacts would be less than significant with mitigation incorporated. The project site is underlain with colluvium and alluvium. During site reconnaissance and laboratory testing, colluvial deposits were found to range from silty clay to sandy clay with some fine gravel. Based on the findings of the geotechnical exploration and laboratory test results, the surficial soils have low to high plasticity and corresponding moderate to high expansion potential. The United States Department of Agriculture (USDA) maps residual soil as Linne clay loam, predominantly of dark brown, silty or sandy clay. The residual soil appears to be dry and hard without significant porosity. Based on visual examination, residual soil appeared to have moderate to high plasticity and may be highly expansive. The proposed project would implement MM H1, which requires preparation of a soils study, and MM H8, which includes foundation and improvement requirements designed to reduce impacts related to expansive soils. Therefore, the proposed project would not result in any peculiar effects and would not result in new or more severe impacts related to expansive soils beyond what was previously analyzed in the 1998 HVSP FEIR. e) Septic Tanks Would the project: Have soils incapable of supporting the use of septic tanks or other alternative wastewater disposal systems where sewers are not available? This question was not included in the 1998 HVSP FEIR. No determination was made in the 1998 HVSP FEIR regarding the level of significance related to septic tanks or other alternative wastewater disposal systems. The project site is located across from a developed residential area in the City of Pleasanton, which is adequately served by the municipal sanitary sewer system. The proposed project would be served by an 8-inch sanitary sewer line that would connect to an existing 8-inch line on Alisal Road. There is also an existing 8-inch sanitary sewer line on Westbridge Lane. Therefore, the proposed project would not result in any peculiar effects and would not result in new or more severe impacts related to septic tanks or alternative wastewater disposal systems beyond what was previously analyzed in the 1998 HVSP FEIR.