New London ― Construction crews on Monday were putting the finishing touches on a Jefferson Avenue repair project that became necessary after new catch basins on the busy street were installed incorrectly.

The drainage basins were originally added months ago as part of a $3.9 million state- funded project paid with Local Transportation Capital Improvement Program, or LOTCIP, funds administered through the Southeastern Connecticut Council of Governments.

The initial work meant digging up and rebuilding roughly 2,500 linear square feet of Jefferson Avenue and construction of a “three-legged” roundabout near the high school, with new sidewalks, crosswalks, lighting and curbing.

But several weeks ago, after paving was completed, an inspection showed undulations in the road in the areas of the basins, Director of Public Works Brian Sear said.

“If you drove over them, you’d notice a wobble with some areas worse than others,” he said. “In the field, the elevation of a water main under the road wasn’t properly taken into account, which involved just fractions of inches, but meant the elevation of those basins were too high.”

Sear said he met with state Department of Transportation and SECCOG officials about three weeks ago to brainstorm a solution that wouldn’t violate LOTCIP spending guidelines.

“This is a municipally administered project, but the state does audit the work,” he said. “The project language required this road to have a life of between 20 to 30 years, which it wouldn’t if we left the basins as they were.”

Kate Rattan, SECCOG’s transportation program manager, said the basin issue arose from a combination of “utility conflicts” found on and under the road, including a bicycle lane with a different slope elevation than adjacent road gutter.

“These things happen out in the field,” she said. “Luckily, we can lean on the expertise of DOT and were able to coordinate a solution. And the good news is the repairs will not mean any additional expense to the town.”

Ultimately, the tops of 12 basins were lowered by about three inches using a combination of more compactable concrete and flatter basin tops. Final sealing work on the repair job was being conducted Monday morning.That work was paid for with a pool of contingency funding included in the original funding package.

Sear praised DOT and SECCOG officials for working with the city on the repair plans.

“There’s no bad guy in this scenario,” he said. “The paving itself was excellent.”

The roundabout portion of the work was largely completed in August, though several aesthetic pieces on the center island, including a sail-shaped flag and landscaping, have not yet been placed. Final crosswalk striping of the roundabout is expected to be finished by the end of the year.

Editor’s note: This version corrects the acronym for the state Local Transportation Capital Improvement Program.

j.penney@theday.com