An ongoing construction project to replace a pair of aging wastewater tunnels in Los Angeles with a 7-mile-long precast concrete tunnel is getting a financial boost from the U.S. Environmental Protection Agency.

EPA is providing a $441-million Water Infrastructure Finance and Innovation Act loan to the Los Angeles County Sanitation Districts for the joint water pollution control plant effluent outfall tunnel, also known as the clearwater project. EPA says Los Angeles County will save about $76 million by financing with the WIFIA loan. 

“This loan will help us build infrastructure that is critical for the region and minimize the financial impact on our ratepayers,” Robert Ferrante, chief engineer and general manager of the sanitation districts, said in a statement. 

The 18-ft-dia tunnel will carry treated water from the joint water pollution control plant in Carson, Calif., to ocean outfalls in L.A.’s San Pedro neighborhood. The new tunnel will have a greater capacity for high flows than the existing tunnels, which were built in 1937 and 1958.

Officials from the county sanitation districts say two major storms almost pushed the tunnels past their capacity. The tunnels, which cross two earthquake faults, also do not meet modern seismic standards. If the capacity is exceeded or the tunnels fail, sewage could discharge into surrounding waterways. After the new tunnel is built, the existing tunnels will be used for backup.

The project has been in the works for several years. Parsons Corp. and McMillen Jacobs Associates with geotechnical engineer Fugro Consultants completed design in 2018. In 2019, the sanitation districts awarded a $630-million construction contract to Dragados USA Inc. Tunneling began in 2021. Officials expect the tunnel to be finished in 2027. 

tunnelAlignment.jpgThe planned tunnel will replace two existing tunnels. Image courtesy of Los Angeles County Sanitation Districts


WIFIA loans, low in cost and long term, are given for significant water infrastructure projects. EPA is financing more than $31 billion in water infrastructure upgrades with WIFIA loans, according to the agency. On May 9, EPA also announced it would provide $65 million in loans for two projects that will increase groundwater treatment capacity in Oregon's Multnomah County.