Overwhelmed sewer systems take toll on beaches

Last week’s rainstorms offered stark illustrations of the destructive power of a strong downpour: Homes besieged by mud, flooded roadways and beaches littered with washed-up garbage.

But a less visible blight also took a toll on the Southern California coastline.

As dirty storm runoff rushed seaward during the rains, it overwhelmed some of the region’s sewage systems, rupturing sewer mains, disabling pump stations and surging above manhole covers in a series of spills that swept hundreds of thousands of gallons of waste into the ocean.

Five days after the heaviest rainfall, several beaches, including three in southern Orange County and two in San Diego County, remained closed to protect the public from sewage, pathogens and other pollutants that continue to swirl in the water even after the storm clouds have dissipated.

“With this volume of water, a lot of things that have been sitting for a long time all got washed down,” said Garry Brown, executive director of the nonprofit Orange County Coastkeeper. “There are viruses, toxic metals, trash and debris polluting the coast, and it’s the things you can’t see that are more detrimental to human health.”

When mud and debris streamed through the streets of downtown Laguna Beach early Wednesday during heavy rains, more than 60,000 gallons of sewage washed toward the ocean.

Some of the waste came from broken pipes on private property or sewer lines overflowing with storm water. But the highest volume spilled from the sewer infrastructure.

A pump station ruptured near Laguna’s popular Main Beach and sent 47,000 gallons of sewage seaward while a second station on the outskirts of the city broke and spilled 6,000 gallons of sewage into Aliso Creek. In both cases, the rain caused the volume of material flowing through sewage pipes to double, overwhelming the system.

The mechanical equipment in Laguna Beach “couldn’t keep up with the material that was coming through,” said Tom Rosales, general manager of the South Orange County Wastewater Authority. “Mud, rocks, sticks, you name it — whatever was flowing down the hill, it was making it to the treatment plant.”

Water quality advocates, however, say wastewater agencies should have been prepared to accommodate the stress of a major downpour.

“In our eyes, too much rain is not an excuse,” said Brown, of Orange County Coastkeeper, who added that he plans to seek records from wastewater agencies to find out what exactly went wrong. If it turns out that the spills could have been prevented through improvements to aging pipes, pumps and other infrastructure, the group could file complaints with water quality regulators, he said.

The storms caused similar complications elsewhere.

The series of spills initially prompted Orange County health officials to close a 12-mile stretch of coastline from Crescent Bay in Laguna Beach to Poche Beach in San Clemente. A smaller, 4.3-mile area of the county, including Laguna Beach, Aliso Beach and Doheny State Beach remained closed to swimmers and surfers Monday.

In nearby San Juan Capistrano, runoff-swollen Trabuco Creek damaged a 30-inch main, spilling 50,000 gallons of partially treated sewage.

A sewer main damaged during heavy rains at Camp Pendleton sent more than 1.1 million gallons of partially treated sewage into San Mateo Creek and closed beaches near the creek’s outlet at San Onofre State Beach. The spill, which is believed to have occurred Dec. 21, wasn’t discovered until three days later. The beach remained closed Monday.

San Diego’s Ocean Beach was still closed five days after an estimated 750,000-gallon spill. That incident occurred after Sycamore Creek in the suburb of Santee overflowed, flooding a wastewater pump station, forcing sewage out of manhole covers at a golf course, and sending it flowing into the San Diego River.

tony.barboza@latimes.com