The month-long closure of an important artery between the San Fernando Valley and Beverly Hills is expected to clog other routes. But officials say it's necessary for a vital water delivery makeover. Angie Crouch reports from Studio City for the NBC4 News at 5 p.m. on March 22, 2013.
Saturday marks the beginning of more traffic detours in Los Angeles, including a month-long closure of Coldwater Canyon Avenue and a one-night closure in the Sepulveda Pass along the 405 Freeway.
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Both routes are critical connectors between the San Fernando Valley and the Westside of LA so officials are expecting more traffic jams than usual.
405 Freeway Closure: Saturday Night to Sunday Morning
Metro will close four miles on the northbound 405 Freeway between the Getty Center Drive ramps and the Ventura Freeway from Saturday night through Sunday morning.
This round of closures are for the reconstruction of the Mulholland Bridge as part of the $1 billion Sepulveda Pass Improvement Project.
Ramps may close as early as 7 p.m. and lanes may close as early as 11 p.m. A full northbound closure will be from 1 a.m. to 6 a.m.
Drivers will be directed onto Sepulveda Boulevard during the closure.
Coldwater Canyon Boulevard Closure: March 23 to April 25
The Los Angeles Department of Water and Power is closing Coldwater Canyon Avenue between Mulholland Drive and Ventura Boulevard from March 23 to April 25.
Crews will have to bore 16 feet below ground to replace a nearly 100-year-old trunk line that ruptured in 2009 with a new welded steel pipe as part of an ongoing city trunk line replacement project, according to the utility's website.
The water main takes water from Sylmar to the Franklin Reservoir in West LA.
Lanes in both directions of Coldwater Canyon Avenue will be closed for construction from 8:30 a.m. to 7 p.m. on weekdays and 8:30 a.m. to 6 p.m. on Saturdays.
The roadway will be open Sundays.
The canyon closure is expected to increase traffic on other surface streets and the two other main canyon roads, Laurel Canyon and Beverly Glen boulevards.
One lane in each direction will be open during non-construction hours. At that time, drivers heading both north and south on Coldwater Canyon Avenue will be prohibited from turning left onto Ventura Boulevard.
Most of the construction will take place at the road's intersections with Dickens Street, Avenida del Sol and Hacienda Drive.
Residents, businesses, churches and schools -- including Harvard-Westlake School, Sunnyside Preschool and St. Michael & All Angels Episcopal Church -- are being issued special access permits to allow local traffic in the area.
LADWP suggested Coldwater drivers take these alternate routes:
View Coldwater Canyon Ave Closed 3/23 to 4/25 in a larger map