SAN DIEGO -- Federal officials in the U.S. and Mexico agreed to probe the circumstances behind a large sewage spill south of the international border that fouled the Tijuana River Valley and nearby beaches in southern San Diego County last month, a San Diego-area environmental group announced Thursday.
Hours ahead of a news conference in which local political leaders and environmental organizations were to push for the investigation, officials with the International Boundary and Water Commission said they would look into the matter, according to the group Wildcoast.
The investigation by the commission's binational Water Quality Work Group will determine when the spill occurred, quantify how much sewage spilled, specify the characteristics of the sewage and identify problems in procedures to notify the commission and the public, Wildcoast said.
The investigation was expected to last 30 days and results were expected by April 1.
"The investigation's going to move forward. We're going to fix this problem once and for all," Imperial Beach Mayor Serge Dedina said.
U.S. officials estimate that more than 143 million gallons of raw sewage flowed from Mexico into the Pacific Ocean, causing a widespread stench that resulted in numerous complaints.
"Residents on both sides of the border just want the same thing, and that's clean water," Coronado Mayor Richard Bailey said.
San Diego City Councilman David Alvarez -- who represents Otay Mesa and San Ysidro -- said the incident put the health of his constituents at risk. Alvarez heads the City Council's Environment Committee.
"Really upset about the lack of action, the lack of clarity, the lack of communication and really the lack of respect to the people that live in this area," Alvarez said.
The news conference was held an hour before a 6:30 p.m. meeting of the commission's U.S. Section Citizens Forum. The commission implements water treaties between the U.S. and Mexico and settles disputes that might arise.
One of the items on the agenda was a report on tracking the flow of solid waste across the border.
"This town absolutely stinks. That's the only way to put it. It was a horrible smell. We've got all that trash coming in," an Imperial Beach resident said.
The San Diego Union-Tribune reported that Mexican officials said the discharge resulted from a project to repair a sewer pipe at the confluence of the Alamar and Tijuana rivers, south of the international border.
U.S. officials weren't notified about the work, however.