A series of water main breaks caused major problems in Mission Valley Thursday, where a geyser shot high into the air along Interstate 8, opened a large sinkhole and forced the closure of all four eastbound traffic lanes.

City of San Diego officials said the breaks may have been related, the result of a chain reaction of failures prompted by changes in water pressure.

Water began flooding the freeway near Hotel Circle South around noon when a concrete water main that measured 8-inches in diameter burst.

At one point, water from the broken line gushed up to 25 feet in the air. Soon afterward, an 8-foot-wide hole formed on the freeway shoulder and in one of the traffic lanes, the California Highway Patrol said.


Hundreds of motorists were left stranded on the freeway, stuck between Taylor Street and Interstate 5. They remained there for more than an hour until they could be diverted off the road, CHP Officer Jim Bettencourt said.

By 1:20 p.m., officers were sending those drivers off the freeway, many of them exiting up the Taylor Street onramp. Water to the broken pipe was shut down around 2:30 p.m.

CHP officers closed ramps to eastbound I-8 in both directions from Interstate 5 as well as the onramps to I-8 from Rosecrans and Morena Boulevard. Hotel Circle South also was closed.

That caused traffic to back up on I-5, state Route 163 and other busy roadways as rush hour approached. By 6 p.m., Caltrans crews had evaluated the lanes closest to the median on eastbound I-8 and determined that the pavement was not damaged.


They reopened two of the four lanes, as well as the onramps from I-5.

A snapshot of freeways in San Diego, taken around 4:20 p.m., shows the traffic jams created by the closure of eastbound Interstate 8 Thursday.

City officials said there were breaks in four water mains Thursday, with the first one reported around 9:30 a.m. along Morena Boulevard near Savannah Street.

Over the next few hours, two other mains on Morena also broke, including one at Frankfurt Street and one at Knoxville Street, said water spokesman Arian Collins.


“All three are part of one long pipeline,” Collins said. “The Morena Boulevard ones are definitely related. It is too much of a coincidence. We think the one at Hotel Circle may be as well. It may be that a pressure change caused a chain reaction.”

Collins explained that when crews were trying to shut off water at one of the earlier breaks, it may have caused a pressure change that triggered the main under the freeway to burst.

The Hotel Circle pipe runs underneath I-8 and connects one side of Mission Valley to the other. Several hotels were reported without water after the break, Collins said.

“The pipe (under the freeway) itself may have been disintegrating already, we don’t know for sure,” he said. “This will all be part of the investigation.”


For now, city water crews will focus on working on repairing the pipes and restoring service.

“We have every available crew member working right now,” he said. “They will be working through the night… Most likely, it will be tomorrow before all four of them are repaired.”

Caltrans spokeswoman Cathryne Bruce-Johnson said state repair crews would begin their work after the city finishes repairs to its water main. Workers will be assessing the sinkhole and the condition of the freeway to determine what work is needed.

“The city crews will have to do their repairs before Caltrans maintenance crews can go in and determine the scope of the repairs that are needed for the highway, and then we can proceed with our part of the work,” Bruce-Johnson said.


She had no estimate as to when repairs would be finished or when all freeway lanes would be reopened.

Staff writer David Hernandez contributed to this report.


karen.kucher@sduniontribune.com

UPDATES:


8:15:p.m.: This article was updated with additional details.

The previous update was at 3:45 p.m.