DENVER -- Interstate 25 reopened at 6:37 p.m. Friday as crews continued to repair a 40-foot-wide sinkhole on Interstate 25 Friday that shut down northbound lanes and backed up traffic for 10 miles during the Thursday afternoon commute.

The sinkhole, at I-25 at 58th Avenue, was caused by a 66-inch-diameter conduit that broke, sending 2 million gallons of water under the highway.

The first 911 caller to report the water main break told the dispatcher, "The highway is broken." Click here to hear the 911 call.

The damaged northbound lanes were given a temporary patch and new lane markers were painted -- making the lanes a foot narrower than normal. As a result, the speed limit through the affected section will be 45 mph when traffic is allowed through. Two HOV lanes will remain northbound only, giving motorists five lanes of northbound traffic while crews continue to repair the break.

About 150,000 to 200,000 cars drive through that area daily, and CDOT said opening up I-25, the busiest highway in the state, is their No. 1 priority. Crews from other road projects have been pulled from their jobs so they can help with emergency repairs, Stegman said.

"We know how bad it is. You take one lane away from this highway and it backs traffic up horribly," she said.

The Denver Water Department said the break was likely caused by a pressure surge following a small fire at a nearby pump station.

Brian Good, Director of Operations and Maintenance explained employees at the pump station reported seeing smoke and were unable to shut down the station. Water flow to a major portion of the city could’ve been affected had the problem continued, according to Good.

“They hit the big red button for emergencies. That did stop the pump and stop the fire, but caused a pressure surge which blew the pipe,” Good said.

Department spokeswoman Stacy Chesney said the leak reduced water pressure for some customers but no one lost service.

Northbound traffic had to squeeze into the HOV lanes or use jam-packed city streets Thursday afternoon. The traffic jam cleared out by 7:30 p.m..

A water main broke in this same area in May 1997. There was so much water that people ended up going to the roof of the Sofa Mart Furniture Store.

The last time there was a major sinkhole in Colorado was in the summer of 2003 on Interstate 70 near Vail. A large section of the highway was washed away. Repairs took 11 days.

"This is double that size," Stegman said. "It's by far the largest sinkhole I've ever seen and I've been with the department for 12 years."

Neither CDOT nor Denver Water officials speculated on total repair costs.

“The most important thing is getting it done right and safely, then we’ll assess cost at a later date,” Good said.

“That’s for another day’s discussion,” said Russell George, Executive Director for CDOT.

CDOT expects traffic to be reduced to three lanes at least through the weekend.

Were you stuck in this traffic Thursday? Did you see the wall of water pour over the concrete barrier when the pipeline first burst? Tell us your story, or e-mail us a picture! Send your e-mail to newstips@thedenverchannel.com.

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February 7, 2008: Sinkhole Shuts Down I-25 At 56th Avenue