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4 Job No. 2669.01 Water Systems Alternative Energy Feasibility Study SECTION 3: DESCRIPTION OF SANTA ANA POTABLE WATER DISTRIBUTION SYSTEM The following information comes from discussions with the Agency engineers, observations at a number of pump stations, and a review of the 2017 Santa Ana Water Masterplan. 3.1 ZONES The city is divided into two zones for potable water supply, the small upper or north zone (northeast of Interstate 5), and the lower or main zone covering the rest of the city. The upper zone is kept at a pressure of about 100 psig, while the main zone was observed to have a pressure of about 70 psig as water leaves the booster pumps, with a lower pressure as it flows through the distribution system. 3.2 TANKS The City of Santa Ana Public Works Agency stores its water in grade level atmospheric tanks, or reservoirs, located around the city, with a total capacity of about 49 million gallons. The tanks are typically from 17 to 35 feet high, with water kept within several feet of the top. This is enough water to serve the city's typical load for more than a day, although it is important to keep the tanks relatively full to meet potential emergency requirements. 3.3 BOOSTER PUMPS Booster pumps (totaling a capacity of 105 million gallons per day and 3,975 hp motor capacity) at each of the tanks pressurize this water from about 6 to 12 psig in the tank to approximately 70 psig for distribution to customers in most of the city, or 100 psig in the upper zone. 3.4 WELL PUMPS Most water is supplied to these tanks by well pumps distributed around the city (21 pumps totaling 5,300 hp in motor capacity). These wells have the capacity to deliver 74 million gallons per day, pumping from a depth of 100 to 300 feet. Fourteen of these well pumps deliver water to the tanks, pumping to 6 to 12 psig. Seven well pumps feed directly into the higher distribution pressure, corresponding to the distribution pressure in that zone. Groundwater in this aquifer is managed by the Orange County Water District in coordination with Metropolitan Water District (MWD). 3.5 MWD CONNECTION POINTS About 25 to 30% of the City's water is delivered directly by MWD to the city's pressurized distribution system through 7 connection points around the city. The connection points use pressure reducing valves (PRVs) to drop the pressure from approximately 160 to 190 psig in the MWD pipes to the city pressure of approximately 70 psig, or 100 psig in the case of SA -6, the one connection in the upper zone. CITY OF SANTA ANA 19H-12 Newcomb I Anderson I McCormick