After initial study of a gaping sinkhole that opened on Iverson Road in Chatsworth during torrential January rains, threatening the lives of four people whose cars fell into the dark hole, Caltrans says the cause was failure of a huge pipe far beneath the road that drains rainwater off the 118 Freeway and into a small creek.
The Chatsworth sinkhole made national news when it swallowed two vehicles, trapping a mother and her daughter in the first car that fell in, which was slammed by a second car that fell into the hole and landed atop the first car. In a dramatic rescue, an airborne Los Angeles Fire Department crew saved the mom and daughter, and the occupants of the second car scrambled to safety.
Soon after, engineers and other experts launched an effort to understand what went wrong on Iverson Road, a residential street very close to the 118 Freeway.
Caltrans spokesman Michael Comeaux says a more than 50-year-old drainage pipe, 50 feet beneath the ground, was to blame. The old pipe split open during atmospheric river conditions and “the drain pipe got clogged with rock and mud” forcing heavy rainwater into the surrounding soil and carving out a sinkhole.
Workers start to repair a sinkhole on Wednesday, Jan. 11, 2023 after it collapsed on Iverson Rd. in Chatsworth where two cars, seen in a pile on left, fell into the sinkhole during heavy rains. (Photo by Dean Musgrove, Los Angeles daily News/SCNG)
Workers continue to repair a sinkhole on Iverson Rd. on Wednesday, Jan. 11, 2023, in Chatsworth where two cars, drove into during the heavy rains. Parts of the front end of the cars sit at the site. (Photo by Dean Musgrove, Los Angeles daily News/SCNG)
Workers continue to repair a sinkhole on Iverson Rd. on Wednesday, Jan. 11, 2023, in Chatsworth where two cars, in a pile, drove into during the heavy rains. (Photo by Dean Musgrove, Los Angeles daily News/SCNG)
Future Los Angele city inspectors got a field trip see the damage and how it’s dealt with crew work cover half the sinkhole to divert rain water, Thursday, Chatsworth CA, Jan 12, 2023. Gene Blevins/Contributing Photographer
Repairs continue on the Iverson Road sinkhole in Chatsworth on Wednesday, Feb. 15 2023 that two autos drive into on Jan. 9. (Photo by Dean Musgrove, Los Angeles Daily News/SCNG)
The early estimated cost to replace the collapsed 5-foot diameter pipe and fix the damage could hit $4 million, Comeaux said, as crews continue to deal with problems left on January 9 by the tangled mess of mud, rock, broken pipe, and utility lines.
He said AT&T took the initial lead to decide how to relocate utility wires including fiber optic, copper cable and other wiring “running right through the sinkhole.”
Experts are assessing the best kind of drain pipe to place under Iverson Road to replace the old collapsed pipe, and, Comeaux said, “We have very many moving parts right now.”
Meanwhile, residents who used Iverson Road to reach a neighborhood nearby are using an alternate route and it will be a long time before the 45-foot-deep, and 50-foot-wide, sinkhole is fully repaired.