SAN DIEGO (Border Report) — The United States and Mexico have agreed to spend almost $500 million to fix a decades-old problem of raw sewage from Mexico spilling onto the Tijuana River Valley on the U.S. side of the border.

The money will come from the United States-Mexico-Canada-Agreement, or USMCA.

The accord was formally signed by representatives of the Environmental Protection Agency and the International Boundary and Water Commission and their counterparts from Mexico.

The signing took place at the Tijuana Estuary, an area that is often impaccted by the sewage, trash and chemicals that flow from Mexico.

“Today is about starting the investment of millions of dollars to clean up the Tijuana River Valley and stop the onslaught of sewage, trash and sediment that’s really affected more than 20 miles of coastline along both sides of the U.S. Mexico border,” said Serge Dedina, mayor of Imperial Beach, Calif.

His city, historically, has sustained the most damage caused by the sewage and debris from Mexico.

“I’m very confident this solution is the answer,” he said.

The money will be used on sanitation and mitigation projects on both sides of the border.

“Most of the money will be spent on the United States side of the border … putting people to work to save the environment, that’s a win-win,” Dedina said.

Mexico has also pledged $144 million to fix its outdated treatment plants and other infrastructure that often breaks down, causing millions of gallons of raw sewage to spill into the Tijuana River Valley and out to the ocean, often closing down the coastline in Imperial Beach and other beach communities on the U.S. side of the border.

“Whatever it takes, we need it to clean up the sewage system, improve it in Mexico,” Dedina said.

According to the IBWC, the projects are expected to be completed and operational by 2027 and are expected to result in a 50-percent reduction in the number of days of “transboundary wastewater flow in the Tijuana River and an 80-percent reduction in the volume of untreated wastewater discharged into the Pacific Ocean.”

USIBWC Commissioner Maria-Elena Giner called the agreement a key milestone in the effort to improve conditions in the Tijuana River Valley.

“Once these projects are completed, residents on both sides of the border will have a healthier, cleaner environment for years to come,” said in a statement.

Others who attended the signing ceremony said the work and investment are long overdue.

“This is a milestone, it brings us one step closer to protecting our communities, the environment, current residents and generations to come,” said U.S. Rep. Juan Vargas, D-California, whose district encompasses all of the California-Mexico border.

U.S. Rep. Scott Peters, a Democrat from San Diego, agreed the money will go a long way to clean up a historical trouble spot along the southern border.

“Nearly 500 million dollars to solve these problems with both of these countries in cooperation, this treaty is enforceable as well, you can rely on this money to come in, this is significant today,” he said.