The US Section of the International Water and Boundary Commission (USIBWC) awarded a contract on August 21 for the rehabilitation and expansion of the South Bay International wastewater treatment plant in San Diego.
The award for the design phase was $42.4 million, but the total project is expected to cost $600 million. USIBWC says the expansion, which will allow the plant on the U.S. side of the border to handle wastewater flows that flow down the Tijuana River and across the border from a failed sewage treatment system in Mexico, it is not yet funded and will require more money from both. countries to stem the flow of raw sewage contaminating cities like Imperial Beach on the US side of the border.
Canadian-based PCL Construction won the contract, with Stantec Consulting Services as the design partner in the contractor-led progressive design effort.
The USIWBC said in a statement that the project will eventually include rehabilitation of existing infrastructure and capacity expansion to double the current treatment capacity of 25 million gallons per day (MGD) to reach an average flow of 50 MGD, with a maximum hydraulic flow capacity of 75 MGD for the South Bay plant. The statement said the project is consistent with a binational agreement reached in 2022 with the Mexican counterparts of the IBWC.
In January, USIBWC Commissioner Maria-Elena Giner said after a visit with her Mexican counterparts and other authorities south of the border, “we have not yet seen any improvement in sewage flows, specifically in terms of reductions in both transboundary flows to the Tijuana River and the South Bay International Wastewater Treatment Plant.”
In March, at a public meeting at the Scripps Institution of Oceanography in San Diego, Giner said, “We want to open these beaches and we want to address public health.”
A 2023 Scripps study said so aerosolized toxins in the surf are causing effects on human health without any contact with the ocean. The city of Imperial Beach’s waters also failed to meet state health standards in 2023, according to the Surfrider Foundation’s 2023 Clean Water Report.
The USIWBC statement said the expansion of the plant, in combination with wastewater infrastructure improvements in Mexico under the 2022 agreement, aims to remove up to 90 percent of non- tracts that reach the coast. He also stressed that continued collaboration between the two nations is “critical to reducing transboundary flows of untreated wastewater.”
The South Bay plant was completed in 1997 and was never designed or intended to treat all Tijuana or Baja California wastewater. Expanding it won’t solve all the problems in the cross-border system, the USIBWC said. The Punta Bandera wastewater treatment plant six kilometers south in Baja California had been used to treat wastewater from Tijuana and Baja California by 2022, but has not been used because a couple of pipes were damaged that supplied the waste water, causing transboundary flows. of the Tijuana River that they have been passing ever since.
USIBWC said it could take up to five years to complete construction of the South Bay expansion project. He said construction is expected to begin later this year with the excavation of the plant’s primary sedimentation tanks.
San Diego’s congressional delegation secured funding after the federal agency said last year that up to $150 million was needed to cover deferred maintenance before the South Bay plant could be expanded. Congressional leaders applauded the contract award and pledged to secure the rest of the money needed.
“After years of investment and attention to planning and permitting, today’s announcement marks a welcome new phase of design and construction in the fight to end beach closures, polluted water from the ocean and the rancid smell of sewage that South Bay and Coronado residents, our Navy SEALs and Border Patrol agents have had to endure,” said Rep. Scott Peters (D-Calif.) in a statement.
