ARCHIVED REPORTS_DRAFT ENVIRONMENTAL IMPACT REPORT

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of City-owned land.Urban landscape irrigation would involve the discharge of approximately 3.28 mgd of wastewater to 817 acres of irrigable City-owned urban land, including parks, schools, cemeteries, and golf courses. All other treated effluent(22.99 mgd)would flow by gravity or be pumped through the existing outfall pipe and a newly constructed outfall pipe to the San Joaquin River. Table 3-4 summarizes proposed treated effluent disposal methods for the WQCF at plant buildout(City of Manteca 2007). Table 3-4 Treated Effluent Disposal Methods at Buildout Disposal Option Average Discharge Rate(Million Gallons Percentage of Total Discharge per Day) On-Site Land Application 0.73 3% San Joaquin River Discharge 22.99 85% Urban Landscape Irrigation 3.28 12% Total 27.00 100% Source:Nolte Associates 2007 The City is currently permitted to discharge 8.11 mgd to the San Joaquin River under National Pollutant Discharge Elimination System(NPDES)Permit No. CA0081558. The permit allows the monthly average discharge to increase to 9.87 mgd in February 2009,provided that additional water quality requirements are satisfied by the WQCF. Completion of Schedule D improvements would achieve these water quality requirements. An approximately 14,000-foot-long by 48-inch-diameter outfall pipeline would be constructed parallel to and south of the existing outfall to accommodate increased flows. The pipe would be routed from the UV disinfection facility along the westerly perimeter of the WQCF property to a side-bank outfall structure at the San Joaquin River(Exhibit 3-3). The outfall structure would consist of a concrete junction manhole for maintenance access, a headwall structure with flap gate to prevent reverse flow, and a concrete spillway to the river edge. Riprap would be provided at the bottom of the spillway for erosion protection and to dissipate energy during peak flows. The spillway would be enclosed on three sides by concrete walls to prevent any spill and to direct flow to the river. The proposed project would expand the existing outfall structure to accommodate a second parallel outfall pipe (Richard,pers. comm., 2006a). To allow for off-line storage and timed discharge, a new secondary effluent equalization pond is proposed for construction north of the existing equalization pond. The City evaluated the potential uses and demand for urban landscape irrigation using wastewater effluent in the 2005 WQCF master plan update. The WQCF master plan identified large irrigation users such as parks, schools, golf courses, and cemeteries throughout the City as potential customers and considered 94 potential sites with an irrigated area of 711 acres(at buildout). To meet California Department of Health Services' requirements for landscape irrigation using unrestricted wastewater effluent,tertiary treatment, and additional disinfection facilities are necessary. With the construction of the Phase III tertiary filtration system(Schedule D project),the potential use of reclaimed water increased significantly. Two projects currently planned for reclaimed wastewater are a water truck fill station for construction site dust control and Big League Dreams softball playing field irrigation. Additional projects including golf course irrigation and other types of landscape irrigation are anticipated by the year 2010. Recycled wastewater effluent water distribution pipelines would be constructed in stages to supply recycled water to areas within the city(Exhibit 3-3). Recycled water storage facilities and a pump station may also be required. Extension of the delivery network to other large, existing, landscape areas would likely occur from 2010 to 2015 (Richard,pers. comm.,2006b). Manteca WQCF and Collection System Master Plans EIR EDAW City of Manteca 3-21 Project Description