The Project is a partnership between the Padre Dam Municipal Water District (District), Helix Water District, County of San Diego, and City of El Cajon for the purpose of creating a new local, sustainable, and drought-proof water supply using state-of-the-art technology. The District previously adopted the Project MND (SCH No. 2018091029), approved a Mitigation Monitoring and Reporting Program (MMRP), and approved the Project in 2018. In February 2020, the East County Advanced Water Purification (AWP) Joint Powers Authority (JPA) approved a resolution considering the Project Mitigated Negative Declaration (MND) under the California Environmental Quality Act (CEQA), adopting the approved MMRP and approving the Project. The JPA is now implementing the Project in east San Diego County. The approved Project will recycle East San Diego County’s wastewater locally, purify the water at an Advanced Water Treatment Plant, and transport the purified water to Lake Jennings for surface water augmentation. The Project is an element of the Comprehensive Facilities Master Plan approved by the District through the 2017 Program Environmental Impact Report. The District is a member of the JPA and the Administrator of the Project. The JPA is the CEQA lead agency for the Project.
The Project will capture and treat approximately 15 million gallons per day of wastewater generated within the East County area to produce an annual average of approximately 11.5 mgd of new local drinking water supply. Byproducts from the Project’s solids handling and AWP facilities will include brine and centrate, collectively referred to as residuals. The approved Project includes a residuals bypass system that will convey brine from the AWP facility, and centrate from the solids dewatering process of the solids handling facility, to an existing regional sewage pipeline (the gravity line) owned and operated by the City of San Diego for treatment and disposal.
In coordination with the City of San Diego, the JPA has evaluated a modification of the approved Project to construct and operate a regional brine line (RBL) to convey the residuals generated by the Project around the City of San Diego’s Pure Water Program facilities. In lieu of discharging the residuals into the existing gravity line as described in the previously approved Project, the RBL would consist of a pipeline built within the existing East Mission Gorge Force Main pipeline and extending from the existing East Mission Gorge Pump Station to the City of San Diego’s South Mission Valley Trunk Sewer. The JPA has evaluated other minor modifications to the approved Project to avoid existing utilities, avoid rocks and hard surfaces, minimize impacts to sensitive biological resources, accommodate alternative construction methodologies, and address new information. The Subsequent MND evaluates the environmental impacts of the Project modifications approved by the JPA.