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ARROYO LAGO RESIDENTIAL PROJECT ADDENDUM FCS 139 Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx iv) impede or redirect flood flows? Prior FEIR Conclusions The proposed residential development area is located within a Flood Hazard Zone X, an area of minimal flood hazard, which is outside of the 0.2 percent Annual Chance Flood Hazard Area. The Prior FEIR determined that the County Project’s design would not impede or redirect flood flows because stormwater would be captured in bioretention areas off-site, which would be designed in accordance with all applicable standards with adequate capacity to accommodate the County Project during storm events to ensure no net increase in off-site flow of stormwaters. Some of the off-site improvements would be located in a FEMA Flood Hazard Zone A, which is an area with a 1 percent annual chance of flooding. The Prior FEIR determined that it would be unlikely that 100-year flood levels would inundate the County Project’s off-site utilities, and the County Project would be required to comply with FEMA guidelines for development within a flood zone. Furthermore, as part of the County’s deliberations and approval, the agricultural irrigation fields were moved west of El Charro Road, into an area designated by Flood Hazard Zone X, which would reduce potential impacts. Therefore, the Prior FEIR concluded that impacts would be less than significant. Proposed Project Analysis and Conclusion The proposed residential development area would remain in an area of minimal flood hazard, as designated by FEMA. Similar to the County Project, the proposed project has been designed to ensure it would not impede or redirect flood flows. Stormwater would be captured in bioretention areas off-site, which would be designed in accordance with all applicable standards to ensure there is adequate capacity to accommodate the project site during storm events to ensure no net increase in off-site flow of stormwater. In addition, for extreme storm events that exceed the capacity of the bioretention system, an overland release in the form of an emergency spillway would safely convey flows in accordance with Zone 7 Flood Control standards and historic drainage patterns as described in the Project Description. As such, impacts would be less than significant, consistent with the conclusions in the Prior FEIR. Therefore, the proposed project would not introduce new significant impacts or create substantially more severe significant impacts than those previously identified in the Prior FEIR. No additional analysis is required. 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? Prior FEIR Conclusions The Prior FEIR evaluated flood hazard risks using the FEMA’s Flood Insurance Rate Maps (FIRMs) and found that the proposed residential development area would be located within Flood Hazard Zone X, an area of minimal flood hazard. Portions of the off-site utility infrastructure (i.e., water storage and booster pump facility and a bioretention area) required for the County Project would be