Roads to Stay Closed in Storms’ Wake : Weather: Motorists are barred from Valencia Boulevard bridge, where a sewer line broke, and Sepulveda Basin.

Traffic on Santa Clarita’s Valencia Boulevard will be disrupted for another week or two until repairs are completed on a bridge where a sewer line broke during weekend rains, spilling hundreds of gallons of raw sewage into the Santa Clara River, city officials said Monday.

And motorists in the San Fernando Valley remained barred Monday from the Sepulveda Basin, which was closed by police Sunday as a precaution because of the continuing rain. Police said the basin would remain closed indefinitely in view of predictions of more rain.

In Santa Clarita, the sewage spill was not expected to pose a health risk or cause lasting environmental damage, state and county officials said.

An estimated 600,000 gallons of raw sewage flowed into the river during a six-hour period Saturday, said Jack Petralia, director of environmental protection for the Los Angeles County Health Services Department. He and Cindy Adkins, a warden for the state Department of Fish and Game, said the river’s rapidly flowing water, enhanced by the weekend’s rain, diluted the sewage to the point where it was rendered harmless.

“Of course, sewage is not necessarily good for the environment,” Adkins said. But she added that in this case, the diluted material was expected to “pretty much degrade” without depleting the oxygen supply to river plants.

Petralia added that the threat to humans posed by raw sewage comes from its high bacterial count and that it was unlikely that any people came into direct contact with sewage in the river.

Rain and soil erosion were blamed for the spill, which county engineers ended by capping the ruptured sewer pipe and building a temporary bypass to reroute its contents. Permanent repairs to the 36-inch sewer line were completed Monday afternoon, Assistant City Manager Ken Pulskamp said.

But repairs to the bridge are expected to take longer and interfere with traffic, said Dennis Welch, street supervisor for the city of Santa Clarita.

Welch said four new pylons must be built to support the bridge, which carries Valencia Boulevard over the Santa Clara River. The old supports were undermined by rushing water during the weekend storms, rupturing the attached sewer line, he said.

Until the repairs are complete, Valencia Boulevard will be closed between Creekside Road and Cinema Drive, and Los Angeles-bound commuters will be directed toward Sierra Highway, the Antelope Valley Freeway, San Fernando Road and Newhall Ranch Road, Welch said.

In Van Nuys, metal gates blocked off access to Sepulveda Basin at Burbank and Victory boulevards and Woodley Avenue.

Los Angeles police closed the basin to motorists over the weekend on the advice of the U. S. Army Corps of Engineers’ dam keeper, Police Sgt. Joseph Brazas said.

Brazas said the dam keeper told police Sunday that the dam’s water level was high, prompting them to close the area to the public. On Monday, Brazas said, the dam keeper advised keeping the area closed because water levels were fluctuating and appeared vulnerable to even slight changes in the weather.

Brazas and a spokesman for the Army Corps of Engineers, Anthony Turhollow, acknowledged that officials want to avoid repetition of the highly publicized emergency that occurred in mid-February, when several dozen motorists were stranded as the basin flooded before it was closed and they had to be rescued by helicopters.

“Let us say this time they’re taking no chances,” Turhollow said.

Brazas said the basin would remain closed until anticipated storms pass through Southern California this week.

Another two to 2 1/2 inches of rain were expected in the San Fernando Valley on Wednesday and Thursday, according to Pat Rowe, a National Weather Service spokeswoman.

Rowe also warned of greater potential for flooding because of saturated soil conditions.

Topanga Canyon Boulevard was closed Monday afternoon between Mulholland Drive and Old Topanga Canyon Road after a section of road sank about eight inches when a drainage pipe ruptured during a storm, transportation officials said. Repairs were expected to take until at least this morning to complete, officials said.