Lodi Surface-Water Treatment Facility
Like so many towns, Lodi, California, saw its subterranean savings account sink after decades of withdrawals. Now, Lodi's new surface-water treatment facility helps conserve the groundwater. We helped develop combined treatment processes that provide a secure, high quality supply of drinking water that's cost-effective for more than 62,000 residents.
Lodi's goal of reducing groundwater pumping in the long-term is part of a regional effort to stabilize the groundwater basin. To achieve this goal, the city is purchasing 6,000 acre-feet per year of Woodbridge Irrigation District's Mokelumne River water entitlement to meet long-term water demands and reduce dependence on the groundwater aquifer. The city's existing water system facilities had to be upgraded and expanded to treat and distribute the purchased surface water.
We first completed the siting study, evaluating the feasibility of locating the new surface water treatment facilities at four potential sites. We then provided conceptual design, predesign, final design, environmental documentation, watershed sanitary survey, permitting assistance, and construction engineering services for the new 11.5 mgd (23 mgd at buildout) facility. The project includes:
- A raw water pumping station with three 50-hp, 5.7 mgd pumps in oversized cans enclosed in a concrete masonry unit block building
- A sedimentation basin followed by automatic strainers for pretreatment
- A Pall Microza pressure membrane system, with an initial firm capacity of 8 mgd, expandable to 20 mgd
- Chemical and disinfection systems
- Residual handling (plate settlers)
- A storm drain system that includes catch basins and a connection to an existing stormwater pumping station
- A high-service pumping station with end-suction centrifugal pumps and CMU building
- A 3 million-gallon prestressed concrete water storage tank
- 2,500 linear feet of 36-inch-diameter water transmission main, and connections to the existing distribution system
- Modifications to 26 groundwater wells with permanent chlorination facilities to ensure compliance with state and federal regulations, as well as sodium hypochlorite tanks, chemical feed banks, online chlorine residual analyzer, SCADA system, and well pump programmable logic controller
- Operations building and chemical building
- Corrosion control