ROCKFORD — The rupture of an abandoned oil pipe and the collapse of a 100-year-old water pipe beneath Keith Creek are driving up the cost of replacing 2 miles of water main near a new Seminary Street bridge.

Workers plugged the oil pipeline and removed soil that had been contaminated. Officials are now also seeking funds from City Council to repair water main beneath Keith Creek that had collapsed during bridge construction last year.

The extra work is adding $504,684 to what had been a $1.5 million project, a 25.8% increase. 

"It's not unlike what we run into in a lot of these older areas where you have old utilities everywhere," Public Works Director Kyle Saunders said. "Downtown we will encounter old steam lines, we encounter old coal chutes. We encounter these things that existed 100-plus years ago and we just kind of play the cards we're dealt, pivot and come up with these kind of innovative ways to solve the problem."

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Saunders said most of the cost increases from the water main project are covered by a $1.9 million Department of Commerce and Economic Opportunity opportunity zone grant that had funded the bulk of the work. Pending City Council approval, water funds will pay for about $45,000 of the additional cost.

What industrial use the oil pipeline had is not clear.

Saunders said tests showed it had held an industrial cutting oil, a small amount of which leaked when the pipe was ruptured during excavation south of the $2.2 million Seminary Street bridge over Keith Creek in the 1100 block of Seminary Street. 

It cost $105,113 to plug the oil line and clean up the spill. 

"We couldn't trace that line back anywhere," Saunders said. "It wasn’t active. It looked like an old carbon steel or old cast iron line that didn't go anywhere. It wasn’t active but was filled with this old cutting fluid that we had to test and abate."

Further complicating matters, officials discovered that old water mains that run beneath the bridge and under Keith Creek had collapsed while the new bridge was built. Plans had been to use a more cost effective technology that utilized the existing water mains by lining them with a "cured in place" pipe. 

That can't be done after the mains collapsed.

To avoid damaging the bridge with a traditional open cut replacement method, Saunders said the new water main will be bored into the ground under the bridge.

Jeff Kolkey: (815) 987-1374; jkolkey@rrstar.com; @jeffkolkey