14 ATTACHMENT 6 - Appendix A - E

City of Pleasanton–Spotorno Ranch Reduced Development Project Initial Study/Consistency Checklist Environmental Checklist FirstCarbon Solutions 121 https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480021/Consistency Checklist/21480021 Spotorno Ranch Consistency Checklist ScreenCheck.docx drain lines with properly sized culverts, improvement of site drainage with earthen vee ditches, and construction of stormwater detention facilities in the Spotorno Flat Area. The 1998 HVSP FEIR determined that implementation of these mitigation measures to control non-point source runoff pollutants and to improve stormwater drainage conditions would reduce impacts to less than significant. The project site consists of mostly undeveloped land. Existing water, wastewater, and stormwater infrastructure is located immediately adjacent, within Alisal Street and Westbridge Lane. The new stormwater drainage facilities would connect to these existing facilities. As discussed in the previous question, the proposed project’s bioretention areas and self-retaining areas, which are discussed in further detail in Section 4.19, Utilities and Service Systems, of the Draft Recirculated EIR, would control the volume and flow of runoff on-site. Additionally, consistent with MM G1, MM G4, and MM G5, BMPs used throughout the site, including landscaping and low-impact design, would reduce the volume and flow rate of stormwater from the site to the storm sewer system to the maximum practicable extent. Compliance with the HVSP MMRP, Alameda County Clean Water Program, City of Pleasanton Municipal Code, and the State Water Board General Permit would ensure that surface runoff would not result in flooding on- or off-site. Therefore, the proposed project would not result in any peculiar effects and would not result in new or more severe impacts related to pollution from runoff beyond what was previously analyzed in the 1998 HVSP FEIR. (iv) impede or redirect flood flows? This question was not included in the 1998 HVSP FEIR. No determination was made in the 1998 HVSP FEIR regarding the significance level of impacts associated with the project’s risk of impeding or redirecting flood flows. However, the 1998 HVSP FEIR determined that project will not increase peak flood flows off-site because it includes installation of detention basins in the Golf Course area and the Spotorno Upper Valley and Spotorno Flat residential areas to mitigate existing localized flooding problems along Happy Valley Creek and Sycamore Creek. The project site is not located within a 100-year flood hazard area or the 500-year flood hazard area. The project site is located in Flood Hazard Zone X, an area of minimal flood hazards.29 Compliance with City regulations including a City Grading and Drainage Plan, Erosion Control Measures, and BMPs would reduce the risk of possible impacts related to flood flows. Therefore, the proposed project would not result in any peculiar effects and would not result in new or more severe impacts related to flood flows beyond what was previously analyzed in the 1998 HVSP FEIR. d) Risk of Pollutant Release Due to Inundation Would the project: In flood hazard, tsunami, or seiche zones, risk release of pollutants due to project inundation? 29 City of Pleasanton. 2009. Pleasanton General Plan 2005-2025, Chapter 5, Public Safety Element, Figure 5-7, Flood Hazard Zones. Website: https://www.cityofpleasantonca.gov/civicax/filebank/blobdload.aspx?BlobID=23899. Accessed February 26, 2021.