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In a bold move to address one of the most persistent environmental and public health challenges on the U.S.-Mexico border, PCL Construction and Stantec have announced a $250 million expansion of the South Bay International Wastewater Treatment Plant in San Diego. According to a recent article in Engineering News-Record, the project has been fast-tracked in response to ongoing cross-border sewage flows from Tijuana, Mexico, and represents a landmark in binational infrastructure collaboration and environmental engineering.
The expansion, awarded under a $42.4 million progressive design-build contract, will double the plant’s treatment capacity from 25 million to 50 million gallons per day (MGD). This represents a significant increase from the previously targeted 35 MGD. This upgrade is critical to mitigating the decades-long issue of untreated sewage entering the Tijuana River and flowing into the Pacific Ocean near the South Bay community of Imperial Beach.
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A Technical Blueprint for Resilient Water Treatment
At a public forum hosted by the U.S. Section of the International Boundary and Water Commission (IBWC) on June 12, Michael Watson, Senior Vice President of Major Projects (Water) at Stantec, and Jeff Newman, Operations Manager at PCL, outlined the technical roadmap for the expansion.
The project scope includes:
• A new integrated headworks system for improved preliminary treatment
• Two new primary sedimentation tanks and 10 secondary sedimentation tanks
• Seven activated sludge tanks to enhance biological treatment
• A new chemical treatment system
• Sludge thickening and storage facilities
• A 12-kV electrical building with upgraded switchgear and transformers provided by San Diego Gas & Electric
“In partnership with PCL, we will work hard to provide the most seamless plant expansion possible,” said Watson. “We believe the repairs and changes we are undertaking will make a measurable difference both now and in the future.”
This expansion is a major milestone for wastewater treatment plant capacity and a model for how modern water treatment infrastructure can be scaled to meet urgent environmental demands.
A Binational Challenge with Global Implications
Mexico’s military has completed the expansion of the Punta Bandera Wastewater Treatment Plant, but concerns remain about long-term capacity and maintenance. With Tijuana’s population doubling over the past two decades, infrastructure resilience is more critical than ever.
The South Bay expansion goes beyond a local project, it’s a model for international cooperation, resilient infrastructure, and environmental justice. It demonstrates how engineering, policy, and technology must converge to solve complex, cross-border challenges.
How GPRS Supports Infrastructure Companies with Precision and Safety
With excavation, retrofitting, and utility integration at the core of the project, GPRS brings essential visibility and verification to ensure construction proceeds safely and without costly delays.
A trusted partner to infrastructure companies across North America, GPRS has demonstrated its value in complex environments, such as a recent California trenching project, helping teams avoid utility strikes and maintain excavation safety.
In projects where excavation, retrofitting, and utility integration are central to success, GPRS supports contractors and engineers by delivering detailed utility mapping and structural scanning before any ground is broken. This helps prevent utility strikes, ensures safe trenching, and allows for confident decision-making during construction. GPRS’ concrete scanning services help identify embedded elements like rebar and post-tension cables, reducing the risk of structural damage during coring or cutting.
Leak detection is another key consideration in wastewater infrastructure. GPRS uses advanced acoustic technologies to identify leaks in pressurized systems, helping project teams maintain system integrity and avoid environmental or operational setbacks. In addition to acoustic methods, GPRS water loss specialists leverage a full suite of tools – including leak noise correlators, video pipe inspection, ground penetrating radar (GPR), and electromagnetic (EM) locating to accurately detect and pinpoint leaks. This service help clients reduce water loss, avoid costly emergency repairs, and maintain compliance with environmental regulations.
Video pipe inspection (VPI) provides a clear assessment of existing underground pipelines, ensuring that legacy systems are properly evaluated before integration with new components.
All this data is captured and delivered through SiteMap® (patent pending), GPRS’ cloud-based infrastructure mapping and facility management platform. It centralizes utility maps, inspection reports, and 3D models in one secure location. Project teams can access this information anytime, from anywhere, from any computer, tablet or smartphone. Improving coordination between field crews, engineers, and facilities managers, SiteMap also streamlines workflows and reduces the risk of miscommunication.
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From skyscrapers to sewer lines, GPRS Intelligently Visualizes The Built World® to keep your projects on time, on budget, and safe.
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FREQUENTLY ASKED QUESTIONS
How does utility locating help prevent delays in wastewater treatment plant construction?
Utility locating is essential in large-scale infrastructure projects like wastewater treatment plant expansions. GPRS uses advanced ground penetrating radar (GPR) and electromagnetic (EM) locating technology to accurately map underground utilities before excavation begins. This prevents accidental utility strikes, reduces costly rework, and keeps construction on schedule.
Why is leak detection important in water treatment infrastructure?
Leak detection ensures the integrity of pressurized systems and prevents water loss, contamination, and environmental hazards. In wastewater and water treatment facilities, undetected leaks can lead to regulatory violations and operational inefficiencies. GPRS uses acoustic leak detectors and leak detection correlators to identify leaks early, helping infrastructure companies maintain system performance and avoid costly repairs.
What role does SiteMap® play in managing complex infrastructure projects?
SiteMap is designed to centralize and simplify access to critical subsurface data. It allows project teams to view and manage utility maps, inspection reports, and site documentation in one secure, cloud-based environment. By organizing high-resolution data collected from services like utility locating, video pipe inspection, and concrete scanning, SiteMap enhances coordination, reduces risk, and supports informed decision-making throughout the lifecycle of an infrastructure project.
