Regional Surface Water Supply Project

About the Project

The Regional Surface Water Supply Project (RSWSP) is a collaborative effort that consists of multiple components, including a regional water treatment facility, raw water pipeline, and treated water transmission mains for both Ceres and Turlock. The RSWSP delivers a long-term, sustainable water source that allows for integrated use of groundwater and surface water and diversifies the water supply portfolios for both Ceres and Turlock.

The Project provides water from the Tuolumne River via an existing set of perforated pipelines installed in gravel about 8-feet below the bottom of the river bed (located just west of the Geer Road Bridge), an intake structure, and a raw water pump station and pipelines. Raw water from the pipelines is treated at the water treatment plant to drinking water standards, and then delivered to SRWA’s service areas for municipal and industrial uses.  TID also uses the raw water facilities to deliver irrigation water to agricultural users.

Construction of the local facilities required for integration of the new water  supply source into their system was the responsibility of each City. The wet well element of the raw water pump station was constructed using a traditional, Design-Bid-Build contracting method. The construction of the wet well began in 2018 and was completed in early 2020. The remainder of the Project was constructed using a Design-Build model. As the name implies, this type of contract is used when both design and construction take place simultaneously throughout the length of the contract. Design-Build projects are typically completed sooner and more efficiently with fewer construction change orders. Project construction was completed in Fall 2023.

The schematic below depicts the water treatment process at the Regional Water Treatment Plant. Water is drawn from the Tuolumne River through perforated pipes in the riverbed and pumped to the Regional Water Treatment Plant. Large particles in the water are removed via the flocculation and sedimentation processes. The water is disinfected using ozone gas and then filtered to remove smaller particles remaining in the water. After treatment, water is stored onsite in a concrete tank where chlorine is added for disinfection before the water is pumped to the Cities of Ceres and Turlock for use.

Project Benefits

The benefits for residents, businesses, agriculture, and government agencies include:

• Diverse water supply portfolios
• Reliable integrated surface water and groundwater systems
• Drought resilient water supplies
• Reliable water quality
• Groundwater aquifer replenishment (as a result of reduced urban groundwater pumping)
• Benefits to the agricultural community associated with reduced urban groundwater pumping, and the delivery of “offset” water to Turlock Irrigation District (from recycled or other water sources) during dry periods
• Increased flows in the Upper Tuolumne River to benefit salmon and other aquatic species
• Potential to provide treated surface water supply to disadvantaged communities and other regional partners
• Decrease in hardness and mineral content in both delivered drinking water and in wastewater effluent discharge