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FINAL DRAFT PRELIMINARY REPORT (Connections to EOCF #2) City of Orange The City of Orange has five (5) primary pressure zones: Zone 370; Zone 490; Zone 736; Zone 900; and Zone 1100. Nine (9) of the City wells pump into the City's 370 Zone and the remaining two (2) pump into the 490 Zone. The proposed new Wells, Well No. 28 and Well No. 29 will also pump into the City's 370 Zone. The East Orange County Feeder No. 2 is mostly located within the City's 370 Zone. In general, the City's 490 Zone is located east of the Costa Mesa (SR-55) Freeway. City of Tustin The City of Tustin has three (3) pressure zones: Zone 1 (HGL of about 308); Zone 2 (HGL of about 380); and Zone 3 (HGL of about 480). The majority of the City is included within the Zone 1. The East Orange County Feeder No. 2 is located within the City's Zone 1. 3.3 Pump Station to East Orange County Feeder #2 In order to convey the excess groundwater from the cities, a pump station will be required to lift the water from the city's pressure zone to the required HGL stated above (HGL of 500 plus all head losses). To maximize the flow potential and to minimize impacts to the city's distribution systems, it is recommended that a new East Orange County Feeder#2 (EOCF#2) Pump Station be constructed. Ideally, it would be beneficial to get the proposed pump station suction from a reservoir instead of from the distribution system. This will require additional lift but will minimize pressure surges and potential pressure impacts to the adjacent distribution system. However, if a reservoir is not available, the proposed pump station can get its suction from the distribution system as long as the pump station design flow is not too high to impact the pressures in the service area adjacent to the proposed pump station. It is not recommended to modify the wells to pump to the higher pressure as this will limit the available excess flow to only what the individual well can produce (which will be lower than normal due to the higher lift). For this study, we have assumed the layout of the proposed EOCF#2 Pump Station will be similar to the South County Zone 1-3 Booster Pump Station designed and constructed for the IRWD Interconnection to SOC Water Transmission Mains. The proposed pump station will include: three or four vertical turbine pumps and motors (including one standby); PRV bypass piping; surge tank on the discharge side; variable frequency drives; building to house the pumps; separate building to house the electrical equipment; and additional surge tank on the suction side if the suction is being provided by the distribution system instead of a reservoir. The following are the approximate footprint dimensions of the proposed pump station: pump room for four pumps, 48 feet by 24 feet; pump room for three pumps, 40 feet by 24 feet; electrical building, 24 feet by 16 feet; and additional site yard to house the surge tank and bypass piping. The approximate total minimum pump station footprint is about 10,000 to 12,000 square feet, with a minimum width of about 50 to 60 feet. See Appendix B for conceptual layout for the proposed pump station and corresponding facilities. The proposed EOCF#2 Pump Station will, most of the time, not be used to convey excess groundwater to South Orange County. Therefore, the proposed pump station will need to be operated periodically to maintain its condition and operation availability. We have assumed a pressure reducing facility will be required to discharge the pump flow back to the city's distribution systems each time it is operated for maintenance purposes. Ideally, the pressure reducing facility should be located in the vicinity of the connection to the East Orange County Feeder No. 2 or at the end of the high pressure discharge piping. 3.4 East Orange County Feeder No. 2 Connections For the initial evaluation of potential location of the proposed facilities, we have assumed that the connection to the East Orange County Feeder No. 2 will be at an existing connection (i.e. do not propose to construct a new outlet to the existing East Orange County Feeder No. 2). Orange 9t9%9 1District/Moulton Niguel Water District 30 - 19 5/17/2 A TECH Evaluation of Groundwater Conveyance Options