14 ATTACHMENT 6 - Appendix A - E

City of Pleasanton–Spotorno Ranch Reduced Development Project Environmental Checklist Initial Study/Consistency Checklist 122 FirstCarbon Solutions https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480021/Consistency Checklist/21480021 Spotorno Ranch Consistency Checklist ScreenCheck.docx The 1998 HVSP FEIR determined that the proposed project is not susceptible to regional flooding hazards, is not located within mapped dam failure inundation areas, and that the elevation of the project site (ranging from 340 to 863 feet AMSL as described in the 1998 HVSP; the current elevations from the development plan for the proposed project range from 380 to 736 feet) and distance from the coast preclude potential inundation by coastal hazards, such as tsunamis, extreme high tides, or sea level rise. Therefore, the 1998 HVSP FEIR determined that this impact was less than significant. Construction of the residential portion of the proposed project would include grading and excavation, construction of structures and roadways, and an increase in impervious surfaces. As part of the project design, two DMAs would be constructed to control and direct stormwater flow toward bioretention and self-retaining areas. There are existing water pipelines located along Alisal Street and Westbridge Lane, to which the proposed project would connect. The proposed project would adhere to the General Construction Permit and Alameda County Clean Water Program guidelines to prevent erosion, flooding, and surface runoff. With adherence to these guidelines and regulations, the project would not result in an increased risk of pollutants due to project inundation. A majority of the City of Pleasanton falls within the 5- to 40-minute inundation area in the event of a Del Valle Dam failure. The project site is located roughly 7 miles west of the Del Valle Dam, and is not within the Del Valle Dam inundation area. The elevation of the project site (ranging from 340 to 863 feet AMSL) and distance from the coast preclude potential inundation by coastal hazards, such as tsunami or seiche. The project site is not located within the 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.30 The nearest Special Flood Hazard Area is located to the west of Pleasanton Sunol Road, 1 mile west of the project site. Therefore, residential units would not be affected by flood zones. Additionally, the project site is not in the Del Valle Dam inundation area.31 The nearest tsunami inundation zone as mapped by the California Emergency Management Agency is 11.5 miles west of the project site.32 Therefore, the proposed project is not at risk of inundation from a tsunami or seiche. The proposed project is not likely to result in impacts because there is a low risk of flooding, tsunami, and seiche at the project site. Therefore, the proposed project would not result in any peculiar effects and would not result in new or more severe impacts related to project inundation beyond what was previously analyzed in the 1998 HVSP FEIR. e) Water Quality Control or Sustainable Groundwater Management Plans Consistency 30 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. 31 City of Pleasanton. 2009. Pleasanton General Plan 2005-2025, Chapter 5, Public Safety Element, Figure 5-8, Del Valle Dam Inundation Area. Website: https://www.cityofpleasantonca.gov/civicax/filebank/blobdload.aspx?BlobID=23899. Accessed February 26, 2021. 32 California Emergency Management Agency. 2009. Tsunami Inundation map for Emergency Planning – Newark Quadrangle, Redwood Point Quadrangle. July 31. Website: https://www.conservation.ca.gov/cgs/Documents/Publications/Tsunami- Maps/Tsunami_Inundation_NewarkRedwoodPoint_Quads_Alameda.pdf. Accessed February 26, 2021.