REGION — The San Elijo Joint Powers Authority was recognized for its water quality assessments near discharged wastewater outfalls in the ocean by the San Diego chapters of the American Public Works Association and American Society of Civil Engineers.
Both associations recognized San Elijo and its partners, Encina Wastewater Authority and the city of Escondido, for their autonomous underwater vehicle plume transport assessments of the San Elijo and Encina ocean outfalls, or locations where a waste stream empties into a body of water.
Working together, the three agencies were able to efficiently comply with ocean discharge permit requirements through economies of scale and collaboration during data collection and analysis.
The three-year project assessed the environmental impacts of two regional ocean outfall systems off of state beaches in Cardiff and South Carlsbad. In total, the outfalls discharge treated wastewater from more than 700,000 residents and businesses in north San Diego County.
Although the agencies have strong recycled water programs that reuse more than 1.5 billion gallons annually, treated wastewater that isn’t recycled is discharged to the ocean.
The study examined ocean water around the outfalls that discharge treated water about 1.5 miles offshore to determine if the discharge has harmful effects on the marine environment. Using underwater drones, the study measured concentrations of salinity, colored dissolved organic matter, fluorescing dissolved organic matter, conductivity, temperature and current.
Based on the data gathering, the firm Michael Baker International concluded in a report that the San Elijo and Encina outfall discharge “has no potential to impact water quality in nearshore and surf zone waters.”
The agencies won a Project of the Year award from the American Public Works Association and an Outstanding Environmental Engineering Project award from the American Society of Civil Engineers.
“Protecting the environment is our top priority,” said Mike Thornton, San Elijo JPA’s general manager. “Last year, we recycled 70% of the flow we received. When we have to discharge to the ocean, we need to ensure that it is not causing harm to the environment.”
The San Elijo Joint Powers Authority is a local leader in environmental stewardship, providing wastewater treatment and recycled water services for the communities of Encinitas, Solana Beach, Del Mar and Rancho Santa Fe.