Bert Crane Wastewater Treatment Plant Discharge Improvements Project

The City of Atwater owns and operates the Bert Crane Regional Wastewater Treatment Plant (WWTP), located on the southeast corner of South Bert Crane Road and Oak Avenue Alignment (APN 056-200-026), which provides tertiary-level treatment for wastewater. Treated effluent from the WWTP is currently released via an effluent pump station and a 42-inch force main into the Atwater/Peck Drain, which flows through Joseph Gallo Farms (Gallo Ranch), where a significant portion is diverted for agricultural and wetland use. In order to meet Sustainable Groundwater Management Act (SGMA) groundwater recharge requirements, the City of Atwater intends to construct improvements to discharge its treated effluent to the Merced Irrigation District (MID) via Black Rascal Creek or Bear Creek. These improvements would connect into the existing force main with a tee fitting and automatic actuated butterfly valves integrated into the City’s SCADA system. The improvements would allow the City to redirect effluent flows to the Gallo Ranch, the creeks, or both. A Discharge Study was prepared to evaluate three (3) alternatives for future improvements for discharge into either Black Rascal Creek or Bear Creek: Alternative 1 – Bert Crane Road Alignment, Alternative 2 – South WWTP Alignment, and Alternative 3 – Deckert Lateral Alignment (Figure 2 5). All three (3) alternatives shared common infrastructure improvement recommendations, such as connecting to the existing force main from the WWTP, construction of a new pump station, and construction of an outfall structure. The following summarizes the recommended improvements that are applicable to each alternative: • Installation of a 42-inch x 42-inch x 18-inch tee • Installation of a 42-inch automatic actuated butterfly valve • Installation of an 18-inch automatic actuated butterfly valve • Installation of an air relief valve • Installation of an 18-inch magnetic flow meter • Construction of a pump station • Installation of power source and connection to City SCADA system • Construction of an outfall structure equipped with a flap valve. The alternative specific improvements are as follows: • Alternative 1 would include construction of 4,400 linear feet of 18-inch pipeline, traffic control, and flow diversion and dewatering. A new outfall structure into Bear Creek would be constructed. • Alternative 2 would include construction of 4,300 linear feet of 18-inch pipeline and flow diversion and dewatering. A new outfall structure into Black Rascal Creek would be constructed • Alternative 3 would include connection to the existing Deckert Lateral culvert, construction of 5,400 linear feet of 18-inch pipeline, increases to MIDs Deckert Lateral capacity, replacing the existing MID outfall structure to Black Rascal Creek, and traffic control. The environmental review evaluates the potential environmental impacts of all three (3) proposed alternatives—Alternative 1 (Bert Crane Road Alignment), Alternative 2 (South WWTP Alignment), and Alternative 3 (Deckert Lateral Alignment).