BARRINGTON, R.I. (WPRI) — Emails and documents obtained through an Access to Public Records Act request indicate repairing a public water pipeline under a troubled bridge will cost taxpayers just under $400,000, but the cause of the damage remains a mystery, Target 12 has learned.

A July 30 email from Pare Corporation to the Rhode Island Department of Transportation stated “the total estimated cost for this project is $424,350” to repair a 12 inch water line that was part of the original project. RIDOT spokesperson Charles St. Martin said the winning bid came in lower than that, at $320,000. A $48,000 consultant fee brings the projected repair cost to about $368,000.

As far as the cause, there are no answers yet.

“The consultant found that the pipe design was vulnerable to damage as the result of external forces,” St. Martin said. “The external force that resulted in this damage may never be known.”

Replacing the old bridge over the Barrington River was contracted in 2003. The bridge opened to traffic in 2009, several years overdue, and about $10 million over the initial projected price of $10.3 million.

The pipeline was never put in service according to Bristol County Water Authority Executive Director Pam Marchand, who said the pipe provides a backup supply to Barrington and also serves as an emergency supply line to Warren if the 24-inch main supply line from Providence is ever out of service.

Marchand has said the water authority is also stumped about the cause of the damage which was discovered last fall. But she did offer one possibility in an email to Target 12 last May.

“To my knowledge, the pipe was never put in service,” Marchand said. “But it was chlorinated and pressure-tested and was left filled. We assume the lower section did not drain. Perhaps the unusually cold winter caused some problems?”

St. Martin said RIDOT expects work to begin within the next two weeks but he added that will depend on obtaining the necessary permits. He said the weather conditions permitting, the project should be wrapped up by the end of November.

“Crews will most likely work off of a barge from beneath the bridge or from above using a bridge snooper truck,” St. Martin said. “Depending on the final plan, there may be some intermittent impacts to vehicles or marine vessels.”

According to Marchand, problems with the pipeline were discovered in 2010, around the time the bridge finally opened. It was almost a 20 year wait for the ribbon cutting since RIDOT first announced the need to replace the bridge in 1994.

Shire Corporation was awarded a $10.3 million contract in 2003, but on the first of several projected completion dates of September 6, 2006. At the time, RIDOT said the project was 30 months behind schedule and $3.5 million over budget. It would only get more expensive to taxpayers with the cost eventually ballooning to more than $20 million.

Send tips to Target 12 Investigator Walt Buteau at wbuteau@wpri.com and follow him on Twitter @wbuteau