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FINAL DRAFT PRELIMINARY REPORT (Connections to EOCF #2) EVAULATION OF GROUNDWATER CONVEYANCE OPTIONS INTRODUCTION 1.1 History/Purpose of Evaluation Retail water agencies in southern Orange County rely primarily on imported water supply from Metropolitan Water District (MWD) and surface storage to meet daily operational demands and fire storage. With heavy reliance on the imported water sources, the South Orange County (SOC) water agencies have a much higher vulnerability during outages of MWD imported water facilities as opposed to water agencies in northern Orange County which have the capability of drawing groundwater from the Orange County Water District's (OCWD) Groundwater Basin. In 2006, OCWD entered into an agreement (Emergency Services Program) with South County Agencies to allow up to 50 cfs of groundwater to move from the basin to South Orange County for up to 30 days in the event of an outage of MWD's imported water infrastructure. OCWD and Moulton Niguel Water District (MNWD) have requested a study be performed that will provide a review, summary and analysis of conveyance options from the Orange County Groundwater Basin to regional water transmission mains serving South Orange County water agencies. In general, the goal of the study is to evaluate the potential infrastructure and property acquisition required to convey water (in the range of 30 cfs to 50 cfs) from the Orange County Groundwater Basin to Moulton Niguel Water District's distribution system via the regional imported water pipelines. This information will be used by OCWD and MNWD to assist in the potential development of a pilot program to convey groundwater to MNWD during emergencies. 1.2 Study Description MNWD currently shares an emergency interconnection through Irvine Ranch Water District which can move up to 30 cfs of water to serve South Orange County. MNWD owns 55 percent of the capacity of the interconnection. Due to growth in Irvine Ranch Water District, expiration of the capacity rights in the interconnection facilities, and uncertainty in the ability to convey water into the future, MNWD is interested in alternative conveyance options to move water from the groundwater basin to MNWD during an emergency. MNWD currently receives imported water from the East Orange County Feeder #2, Allen -McCulloch Pipeline and/ or the South County Pipeline. The study will evaluate potential costs of land acquisition, building new transmission mains and/or pumping plants, utilization of existing available groundwater well capacity or construction of new wells, and connection of transmission mains to the East Orange County Feeder #2. The following is a brief summary of the items that will be addressed in the study: Meet with cities of Santa Ana, Orange and Tustin to discuss the agencies existing conveyance facilities, well production facilities, and desired capacity and conveyance goals. The intent of this scope item is to determine the available capacity, if any, the agencies may have to participate in providing emergency water. Using data obtained from OCWD and the water agencies, identify alternative locations for developing the desired pumping capacity utilizing either available well capacity or developing new well capacity. Focus will be on areas adjacent to the East Orange County Feeder No. 2 within the cities of Santa Ana, Orange and Tustin. • Evaluate the existing and new infrastructure necessary to convey the stored water from the identified pumping or well locations to East Orange County Feeder #2. Prepare typical connection facilities including meters, pressure and flow control and valving. Orange 9t9%9 1District/Moulton Niguel Water District 30 - 13 5/17/2 A TECH Evaluation of Groundwater Conveyance Options