The scope of an urgent public works project to replace a collapsed large metallic culvert that passes beneath Mile Hill Road has expanded substantially, with the work required to fix the high-priority problem being more extensive than was initially thought.

State Department of Transportation (DOT) spokesman Kevin Nursick said June 18 that an initial estimate of $200,000 worth of construction work being needed to fix the problem was made before the DOT was able to inspect the extent of damage to the five-foot-diameter culvert.

The 130-foot-long pipe is intended to carry Deep Brook diagonally south-to-north across Mile Hill Road, about 30 feet beneath the pavement. Notably, the tributaries of Deep Brook along its lower reaches are in a state-designated wild trout management area and are considered prime breeding areas for native brook trout.

“The cost will certainly exceed [$200,000], and funding will not be an issue,” Mr Nursick said. Initially, DOT had expected that the problem would be resolved by the end of June. It now, however, is unclear when the work would be completed.

“We do not have a time frame to provide at this point,” he said.

“Whether we move forward immediately or at a later date is still to be determined,” Mr Nursick added.

Staffers for Empire Paving, a North Haven-based general contracting firm, have been working at the drainage repair site for the past several weeks. The worksite is located at the base of an embankment, on the south side on Mile Hill Road, adjacent to the road’s eastbound lane. Work began April 30.

Concrete barrier rails have been placed on Mile Hill Road between its intersections with Tinkerfield Road and Mile Hill Road South. Those rails have redirected traffic flow on the street away from its south side and the embankment where repairs have been underway.

Deep Brook has been diverted to the west to keep it from entering the extensively damaged metallic culvert beneath the road. The damaged pipe is about 80 years old.

To stabilize the eroded southern embankment of Mile Hill Road, workers have brought in a crane and are using it to lift large steel beams or pilings, which are hoisted and then vertically inserted into the embankment. Spaces between the beams are filled with wooden spacers. The bank stabilization is necessary for the culvert’s replacement.

If the failed metal culvert is completely replaced, it likely would be with a concrete culvert that is 130 feet long and eight feet in diameter, Mr Nursick said.

However, the specifics of the repair project are yet unclear, he said. “[Culvert] replacement should be possible without too much disruption to traffic,” he said.

Due to the drainage pipe’s collapse, Deep Brook’s water initially was ponding at the foot of the embankment and backing up. Workers were then using large pumps to channel water out of the area.

Although short in length, Mile Hill Road is a link in the roadway that interconnects Route 25, Route 34, and Interstate 84. When necessary, traffic on the affected section of Mile Hill Road travels alternately in two directions and is controlled by signalmen.