Imperial Beach lifeguards were ordered to close the IB shoreline around 11 a.m. Tuesday morning by the San Diego County Department of Environmental Health (DEH). Closures have been on and off for the better part of the last month.

Starting Dec. 18, closures continued until Jan. 6, opened for a day, then closed again until a few days ago. With a few exceptions, such as the area used by harbor seals in the Children's Pool in La Jolla, closures and general advisories were lifted for all other San Diego County beaches almost two weeks ago.

According to the Mexican environmental group Frontier Project of Environmental Education, which claims to have spoken with Mexican officials, 31 million gallons of sewage have spilled into the ocean near Playas de Tijuana just south of the border since Dec. 23 due to a failing collector pipe.

Sally Spencer with the International Boundary and Water Commission (IBWC) said Mexican officials started repairs to the collector Tuesday afternoon, and that the pipe will release 70 liters of sewage a second until repairs are finished at the end of the week. However, she did not receive confirmation of any other recent spills in the area.

In the event of a spill in Mexico that may impact ocean water in the U.S., the IBWC is supposed to be notified by Mexican officials, then word goes out to state and county public health officials. The city of Imperial Beach receives notification as well.

Mark McPherson, chief of land and water quality for the DEH, said tests of water quality performed Tuesday in Imperial Beach will be available Wednesday. The closure was "preemptive," he said, but results typically verify water is unfit for human contact. Tuesday's closures came after county health officials detected an odor in the area and the plume tracker, which detects the Tijuana River's outfall, showed a northerly flow.

Test results since the start of the supposed spill have not shown any irregularities, he said, since about 23 million gallons of sewage contaminated runoff have flowed from the river to the ocean every day during that period.

"We've had so much time to test down there; we're not seeing anything out of the ordinary," he said.

"An extra 31 million gallons farther down south over a couple week period, compared to what's going into the Tijuana River every day ... it's not a lot."

Serge Dedina, executive director of WiLDCOAST, sees a much larger impact from the spill.

"It would have been nice to have been notified about this," he said. "I’d say that the strong odors for closure two weeks ago and this week are tied to this spill-not just river flow."

"This demonstrates a complete breakdown in binational agency communication that has threatened the health of thousands of ocean users since before Christmas and more than likely resulted in at least two rounds of extensive beach closures in Imperial Beach."

The U.S. portion of the International Boundary and Water Commission will host a Citizens Forum Thursday from 6 p.m. to 8 p.m. at the Tijuana Estuary Meeting Room to discuss water quality, recent conditions in the Tijuana River basin and listen to the community.