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ARROYO LAGO RESIDENTIAL PROJECT ADDENDUM 52 FCS Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480036/Addendum/21480036 Arroyo Lago Residential Project Addendum.docx In order to protect structures from flooding at the project site, the overland release would direct most of the surface flow south to Busch Road, but a portion of the project site starting from approximately Lot 118 and proceeding north has been designed to be captured in a secondary overland release inlet which would convey the stormwater into an approximately 24-inch diameter pipe that would connect with an existing storm drain line in Mohr Avenue. All stormwater infrastructure improvements would be designed and constructed in accordance with all applicable requirements set forth in the City of Pleasanton’s Standard Specifications and Details and implemented through the City’s COAs for the proposed project. Zone 7 Stormwater Option The proposed project includes another stormwater management configuration that would be implemented only if approved by the Board of Directors of Zone 7. This option would allow treated stormwater from the proposed bioretention areas to discharge to lands located east of El Charro Road, from which flows would ultimately drain toward Cope Lake. Under this configuration, the proposed project would continue to treat stormwater through the proposed bioretention facilities (as described above) in compliance with applicable water quality standards. However, rather than conveying treated stormwater via a detention basin, pumps, and a storm drain force main, the treated flows would be discharged from the bioretention areas and allowed to drain naturally toward Cope Lake, consistent with the historic drainage pattern that has conveyed runoff from these parcels toward Cope Lake. As a result, the detention basin, pump facilities, and storm drain force main described above would not be constructed. While the proposed project has been designed to avoid direct stormwater discharge to Cope Lake via the City Stormwater Option, the project entitlements would also incorporate the ability of the applicant to pursue the Zone 7 Stormwater Option instead, subject to Zone 7 approval. This option is included to provide flexibility should Zone 7 determine that discharge of treated stormwater to the land east of El Charro Road is acceptable. The Zone 7 Stormwater Option is consistent with the stormwater design evaluated under the County-approved Tentative Map and considered in the Prior FEIR and, thus, would not introduce new or substantially more severe environmental impacts compared to those analyzed in the Prior FEIR, as detailed more fully in this Addendum. Implementation of this option would remain subject to all applicable regulatory approvals and would be required to comply with City and Zone 7 stormwater requirements, including water quality treatment, erosion control, and post-construction stormwater management standards. Sanitary Sewer Sanitary sewer services for the proposed project would be provided by the City, via a connection to an existing off-site 8-inch diameter sewer line in Mohr Avenue, northwest of the project site. The proposed sewer connection would require that an access easement from Zone 7 Water Agency, the property owner, be granted to the City. Similar to the proposed water and stormwater lines, the proposed project would construct a new 8-inch diameter sewer line extending from the northwest