Union City sinkhole grows bigger overnight

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A huge sinkhole that developed on a busy street in the East Bay Wednesday has grown in size overnight. 

What started out as a small sinkhole at a busy Union City intersection Wednesday morning turned into big problems for crews Wednesday evening.

The sinkhole was first reported on Westbound Alvarado Boulevard near New Haven by a man who drove over it late Wednesday morning. A city spokesperson said the sinkhole was about the size of a Mini Cooper at that point. A photo taken during lunch hour shows the sinkhole was only about a foot deep.

Then as the afternoon wore on, the road began to buckle more and the sinkhole grew larger and deeper.

By the beginning of the evening commute, the hole had tripled in size, and by Thursday morning it was estimated that the sinkhole could be as deep as 12 feet. 

"I can't believe that this happened on my own street," said Amber Lockwood, who lives nearby. "It's very shocking. You see it on the news in other states or other towns but I can't believe this is happening in my own town."

"It is scary since we live close by and we drive down this road every day," said neighbor Destinee Costodio.

"This is a complex problem," said Lauren Sugayan, spokeswoman for the City of Union City, as she briefed reporters late Wednesday afternoon. "[Workers] will be back out here in the morning to continue their investigation, but most of the time with sinkholes, crews will have to dig all the way to the bottom of it in order to determine the cause."

No one was hurt and no cars were damaged by the sinkhole, according to Sugayan.

The water leak was an unexpected glitch for crews at approximately 7:30 p.m.

Union Sanitary District workers said crews were using underground cameras to try to pinpoint the cause of the problem when all of a sudden, the sinkhole began filling with water.

Water overflowed into the street. Problems escalated when a second leak sprung up.

At last check, workers said they were able to shut off one of them.

Workers told KTVU Fox 2 News that they were able to confirm the sewer line had not collapsed, and that the water flowing into the street was fresh water, not sewage.

Water district workers said they expected to be at the scene overnight trying to find the source of the second leak and figure out what caused it.

It's unclear at this point whether the water leak may have caused the sinkhole, the sinkhole damaged the water line or if another issue was contributing to the problems.

Westbound Alvarado Boulevard is shut down between Fair Ranch Road and Fredi Street until further notice.

The sinkhole is in front of a fire station and the main entrance to Alvarado Middle School. Fire trucks can still get out but parents will need to find a different spot to drop off and pick up their children.

"What we'd ask for parents to do is first of all, allow for extra time when picking up and dropping off for the next few days and for the remainder of the week," said John Mattos, Director of Pupil Services for New Haven Unified School District. "It's going to be pretty busy, I imagine."