Tijuana River Runoff May Impact Swimming in Sunday's SUPERSEAL Triathlon

Sunday will mark the fourth SUPERSEAL Triathlon and first SEAL Sprint at Silver Strand State Beach.

Registration sold out two months prior with 1,400 athletes ready to compete.

However, the San Diego County Department of Environmental Health has closed all beaches from the U.S.-Mexico border to the Silver Strand due to rains flushing sewage-contaminated runoff from the Tijuana River.

“At this point Silver Strand State Beach lifeguards have final say Sunday morning," said Natallie Flinn, an event coordinator with KOZ Enterprise.

If lifeguards deem water quality unfit for human contact, the swimming portion of the triathlon will be canceled. All other San Diego County beaches have been issued a general advisory. Closures and general advisories typically last at least 72 hours, or until water samples can be tested to ensure quality.

The SEAL Sprint starts at 7 a.m. and the SUPERSEAL Triathlon begins at 8 a.m.

“We put on eight triathlons a year and it's always kind of a factor,” she said. “Every time it rains, we face the same problem.”

Of the 1,400 registered athletes, 85 percent are civilians, Flinn said.

This year 1,100 entrants will take part in the SUPERSEAL Triathlon, which is a 1,500 meter swim, 40K bike and 10K run.

First place receives a $600 prize. A total $3,000 will be awarded to top-placing athletes.

The SEAL Sprint is a 500 meter swim, 20K bike and 6K run.

Money raised will go to the Navy SEAL Foundation, which supports Navy SEAL and Special Warfare sailors and their families.

Click here to see a map of race routes.

The 33rd annual SUPERFROG Long Distance Triathlon will take place Sept. 11.