Southbound traffic on a stretch of the Pacific Coast Highway near the Santa Monica border is expected to be impacted at times through the end of 2012, as the city of Los Angeles has begun construction of a new wastewater pipeline, the Department of Public Works announced.

Work on the Coastal Interceptor Relief Sewer will begin at the south end of the project, by the Santa Monica-Los Angeles city border near the Annenberg Community Beach House, and continue heading north to just south of Temescal Canyon Road.

Workers will close up to two southbound lanes along PCH between Entrada Drive and the Annneberg Community Beach House at night through Friday, March 11. Survey work willoccur from 9 p.m. to 5 a.m., with one southbound lane remaining open at all times.

No impacts to the northbound traffic are expected and all traffic lanes will reopen in time for the morning rush hour, a public works spokeswoman said.

Work that could impact highway traffic will then cease temporarily for one month until sewer installation begins on April 11.

The new 4,500-foot pipeline will run alongside the existing Coastal Interceptor Sewer, and will provide increased flow capacity from the eight newly-completed Santa Monica Bay low flow diversions to the Hyperion Treatment Plant in El Segundo, the department spokeswoman said. The project is expected to keep urban runoff from flowing out into the ocean during year-round dry weather, helping the city comply with water quality regulations.

“The CIRS will complement the work of our enhanced low flow diversions that keep urban runoff out of Santa Monica Bay,” City Engineer Gary Lee Moore said. “We appreciate everyone’s cooperation as we deliver this necessary infrastructure development that will promote clean water, protect the ocean, and render critical wastewater services to Los Angeles residents for years to come.”

Regular scheduled work hours are 7 a.m. to 4 p.m. and 9 p.m. to 5 a.m., Mondays through Fridays and some Saturdays. At least two southbound traffic lanes will remain open during daytime work, and at least one lane at night.

The department notes that other potential construction impacts include dust, noise, loss of beach parking during the non-summer months, and a detour option for cyclists. PCH users areencouraged to consider alternate routes.

The $10-million project’s design and construction is managed by the city Bureau of Engineering.

The pipeline and the low flow diversions are funded by the voter-approved Proposition O Clean Water Bond, a $500-million bond that finances 32 stormwater improvement projects across Los Angeles.