L.A. County responsible for polluted runoff that flows into sea, appellate panel rules

In a victory for environmental groups, a federal appeals court panel has found Los Angeles County and the county flood control district responsible for discharging polluted storm runoff that flows down the Los Angeles and San Gabriel rivers to the Pacific Ocean.

An opinion Thursday by the 9th Circuit Court of Appeals sided with the Natural Resources Defense Council and Santa Monica Baykeeper, which argued that the county should be liable for allowing billions of gallons of heavily polluted stormwater to flow untreated each year into the region’s rivers and eventually to the ocean, where it can sicken swimmers and surfers.

“This is a huge win and a turning point for clean water and public health in Southern California,” said council attorney Aaron Colangelo. “The county is now on the hook to clean up this pollution problem, which they acknowledge causes human illness, beach pollution and undermines the regional economy.”

The Los Angeles County Flood Control District, which oversees thousands of miles of storm drains and flood channels in the region, contends that it is not to blame for polluted storm runoff because its infrastructure does not generate or discharge pollutants.

But in a 36-page opinion for the three-judge panel, Judge Milan D. Smith Jr. concluded that it did not matter if the agency was the root cause of the pollution because the district still controlled its flow toward the ocean.

The environmental groups sued the county in 2008 in an effort to get the agency to treat or divert the runoff that is swept into and carries bacteria, heavy metals, pesticides and fertilizer to the sea. Water quality experts have identified storm runoff as the top source of water pollution at Southern California beaches.

The decision reverses part of a lower court’s ruling last year that sided with the county. But it also said environmental groups had failed to show that the county was responsible for pollutants flowing down two other waterways: Malibu Creek and the Santa Clara River.

In a statement, county Assistant Public Works Director Mark Pestrella said that “we do not agree with the technical merits of the court’s ruling on the Los Angeles and San Gabriel rivers” and that the county plans to petition the decision.

The flood control district has argued that its channels and storm drains are merely conduits for upstream polluters and has identified thousands of industrial sites and dozens of cities as sources of the contamination.

In one exchange cited in the opinion, the county claimed it could not be held responsible for dirty runoff even if it were so polluted with oil and grease that it caught fire.

Both sides have agreed that water quality regularly exceeds pollution limits in the region’s rivers and in Santa Monica Bay and that it needs to be improved.

tony.barboza@latimes.com