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FINAL DRAFT PRELIMINARY REPORT (Connections to EOCF #2) The following Table 2.3 summarizes the City of Tustin demands and potential available excess groundwater. Table 2.3 City of Tustin Summary of Demands and Potential Available Excess Groundwater Winter Months (Average) Summer Months (Average) Total Annual Demands (3-year Historical Average) City System Demands 228 MG 320 MG 3,286 MG Import Water 44 MG 81 MG 753 MG Groundwater Production 184 MG 239 MG 2,533 MG Basin Production Percentage 81% 75% 77% Typical Wells Operating (Potential Wells Available for Excess Groundwater) Historical Operation 6 wells operating (2 wells available) 6 wells operating (2 wells available) 6 wells operating (2 wells available) Assuming No Import Water 7 wells operating (1 well available) 8 wells operating (0 wells available) 7 wells operating (1 well available) Note: Above table does not include the future well replacement for the Beneta Well In summary, the City of Tustin does not have excess groundwater that could be available to be conveyed per the Emergency Services Program unless all of their wells are operable and in service and import water is available from East Orange County Water District import connection OC-60. It is possible once a new well is constructed and the RO treatment system for the two wells is placed back into operation that the City may be able to provide up to 3 to 5 cfs excess groundwater during the winter months as is summarized in Section 4. FACILITY SYSTEM CONSTRAINTS 3.1 Hydraulic Grade Requirements Based on the Preliminary Design Report for the Interconnection of the IRWD Water System to the South Orange County Water Transmission System prepared for Municipal Water District of Orange County, dated July 2006, a minimum hydraulic grade line (HGL) of 455 feet is required to meet the South Orange County water agencies system requirements. However, the Joint Regional Transmission Main (JTM) also has a high point at a surge tower within the Laguna Woods community. Based on an assumption of up to 50 cfs of water conveyed to the South Orange County water agencies, the HGL required at the connection to the JTM is 490 to 500 feet. This HGL will meet the requirements of delivering water to MNWD. 3.2 Cities of Santa Ana, Orange and Tustin Pressure Zones The following is a summary of the existing pressure zones for each of the cities under consideration. City of Santa Ana The City of Santa has two pressure zones (High Zone and Low Zone). The High Zone, approximate HGL of about 340 to 350, is located north of the Santa Ana Freeway (the area within the City bordered by the Costa Mesa Freeway, the Garden Grove Freeway and the Santa Ana Freeway). The High Zone has four (4) wells that are currently in operation. The proposed Well 22 replacement is located within the City's High Zone. The Low Zone, approximate HGL of about 270, includes the remaining service area of the City. The Low Zone has fourteen (14) wells that are currently in operation. The proposed new Washington Well is located within the City's Low Zone. Orange 9t9%9 1District/Moulton Niguel Water District 30 — 18 5/17/2 A TECH Evaluation of Groundwater Conveyance Options