Programmatic Environmental Impact Statement for a Suite of Projects to Mitigate Contaminated Transboundary Flows at the U.S.-Mexico Border

photo of stream-like contaminated transboundary water flower of untreated wastewater

Project Brief

The Challenge

Deficiencies in the wastewater collection and treatment network in Tijuana, Mexico, contribute to contaminated transboundary flows of untreated wastewater and trash that enter the United States in San Diego County. These flows threaten the health of the public and border patrol agents, cause frequent beach closures, adversely impact marine and estuarine ecosystems, and cause aesthetic and odor impacts. Consequently, the Tijuana River and Estuary have been listed as “impaired” under Clean Water Act Section 303. In response, the United States-Mexico-Canada Agreement Implementation Act appropriated funds to the U.S. Environmental Protection Agency for wastewater infrastructure projects at the U.S.-Mexico border. Before these projects could begin, they would need an environmental review pursuant to the National Environmental Policy Act.

ERG's Solution

In coordination with EPA and the U.S. Section of the International Boundary and Water Commission, ERG led the development of a programmatic environmental impact statement for the funding and implementation of a suite of wastewater infrastructure projects, collectively referred to as the “USMCA Mitigation of Contaminated Transboundary Flows Project,” costing more than $600 million. ERG prepared an environmental information document, supported an extensive alternatives development and scoring process, coordinated subcontractor surveys for aquatic, ecological, and cultural resources, and developed a comprehensive PEIS that evaluated the proposed projects’ impacts and benefits to wide range of resources and nearby communities. ERG successfully navigated lengthy and complex consultations with the U.S. Fish and Wildlife Service and National Marine Fisheries Service and secured concurrence from the California Office of Historic Preservation and the California Coastal Commission. Finally, ERG drafted the Record of Decision for the PEIS, which was then signed by both EPA and USIBWC.


U.S. Environmental Protection Agency