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DEVELOPMENT PLAN 1 2 z.I.z Wastewater A. Existing Facilities The City of Santa Ana owns and maintains an extensive network of sewer infrastructure, primarily sewer mains, throughout the City. The City mains connect to Orange County Sanitation District (OCSD) trunk sewers throughout the City and convey sewage to OCSD's water reclamation facility in Fountain Valley, processing approximately 117 million gallons per day (MGD) of sewage. OCSD has a 30-inch trunk Memory Lane Interceptor (Interceptor) in Main Place Drive along the southerly mall boundary. The trunk sewer conveys sewage from east to west, under the Interstate 5 Freeway, and connects to OCSD's 78-inch regional trunk sewer that parallels the Santa Ana River along its west bank. The Santa Ana River trunk line conveys sewage southerly, ultimately outfalling at the District's Fountain Valley water reclamation facility. The sewershed that includes MainPlace Mall is largely built -out, aside from potential future redevelopment projects that increase existing density. The City does not have a sewer main in Main Street along the Project frontage. There is a 15-inch diameter City sewer main in Main Place Drive that runs from the southwest mall entry drive to a connection with the OCSD Interceptor. On -site private sewer mains run from north to south on both legs of the on -site ring road. The two on -site sewer branches converge at the southwest mall entry drive and a single pipe connects the MainPlace Mall private sewer system to the City's Main Place Drive sewer main. This City sewer serves the MainPlace Mall site only. B. Proposed Sewer System The majority of the existing sewer system will remain in place, however some wastewater infrastructure will be relocated or extended to accommodate the proposed development program. Existing public Main Place Drive between Main Street and Bedford will be vacated and realigned, and the existing sewer lines which connect to it will be abandoned. Existing sewer lines will be removed and realigned on both the east and west frontages of the mall building. A new lateral will be constructed in Main Place Drive to connect to the City sewer. Figure 2-13, Sewer Plan, shows the existing and proposed sewer system. The proposed sewer system is schematic and may change based on final engineering and building placement. 2.7.3 Grading The site is generally flat with a slight slope from elevation 154 feet above mean sea level (msl) on its western and southern edge to 145 feet msl on its northern and eastern edge. The estimated soil to be exported would range from approximately 350,000 cubic yards (CY) - 440,000 CY. An export of soil is expected due to the projected construction of parking structures and minor grade adjustments across the site. An import of soil of approximately 200,000 CY is anticipated near the west side of the site to provide a level development area. Where possible, soil excavated as part of an individual project will be used for on -site landscape features such as berms or landscaped common space areas. Grading activities will be required to comply with all SCAQMD standards for construction equipment and will also be required to use Tier 4 equipment if it is available. 2.7.4 Drainage and Water Quality 1. Drainage The City of Santa Ana owns and maintains an extensive network of storm drain infrastructure, primarily storm drain mains and catch MAINPLACE SPECIFIC PLAN 1 2-22