Workers for Empire Paving General Contractors of North Haven were back on the job last week at Mile Hill Road, where they are preparing to replace a failed large culvert that formerly carried Deep Brook diagonally south-to-north below that busy roadway.

Workers had been away from the site for the past several weeks as the state Department of Transportation (DOT) studied exactly what construction work needs to be done to get Deep Brook flowing again in its normal course below the road.

In June, workers diverted the northward flow of Deep Brook to the west, which allowed the stream to cross below Mile Hill Road farther to the west. When the repair project is completed, the brook diversion structure will be removed.

On Wednesday, August 14, normal two-way traffic on the affected section of Mile Hill Road was converted to alternating one-way traffic as a construction crew used equipment in finding the underground location of natural gas lines in the area. Knowing where the gas lines are located is necessary so that the planned placement of pilings to stabilize the terrain will not damage those gas lines.

Although short in length, Mile Hill Road is an important link in the roadways that interconnect Route 25, Route 34, and Interstate 84. The part of Mile Hill Road affected by the drainage project is a steeply sloped section of roadway which lies between Mile Hill Road’s intersection with Tinkerfield Road and Queen Street, and its intersection with Mile Hill Road South.

The location of the two travel lanes on that broad 500-foot-long section of Mile Hill Road will be repositioned, as needed, to accommodate work on the drainage repair project.

DOT spokesman Kevin Nursick said the 130-foot-long, six-foot-diameter failed corrugated metal culvert that carried Deep Brook will be replaced by a 168-foot-long reinforced concrete culvert that is seven feet in diameter. The new culvert will be assembled in about 21 segments. That new culvert will be positioned about 30 feet below Mile Hill Road.

The culvert will be installed in two stages, so that no detour would be needed during the repair project, he said. The project is expected to be completed by mid- to late fall. The urgent repair project started on April 30.

The drainage repairs were estimated at about $200,000 last spring, but after the DOT learned the extent of the problem, planned spending was increased to up to $3 million. The DOT has needed to secure environmental protection permits for the project.

Notably, the tributaries of Deep Brook, which lie downstream of Mile Hill Road, are in a state-designated wild trout management area and are considered prime breeding areas for native brook trout.