ROCKPORT — The 15 concrete sections of a new culvert now being laid at the north end of Tolman Pond in Rockport are arriving daily on large flatbed trailers with New Brunswick plates, drawing curiosity for their sheer size.

The Maine Department of Transportation has contracted with Sargent Corporation, of Stillwater, for $329,186 to replace an old culvert that sat beneath Route 90 where Tolman Pond, a manmade body of water created 40 years ago by a dam across the Oyster River channel. The pond is fed by streams running down Mt. Pleasant and Mirror Lake, through a swamp, the West Street Extension wetlands, and then directed to the pond. The outlet of the pond, at the southwest end, eventually feeds into the Oyster River wetlands.

This week, a small Sargent crew, headed by Superintendent Adam Tenan, are piecing together the round concrete pipe pieces, each measuring 96 inches in diameter. Rubber gaskets, like rubber bands, will seal the pieces that are to last, “till we are gone, you and me,” said John Ewer, a Sargent employee.

The culvert is so large because heavy spring and autumn rains tend to fill up the wetlands and Tolman Pond. The culvert, said Tenan, is basically an equalizer, meaning it is often filled with water that balances what is in the pond with the swampy area on the other side of the highway.

According to Tenan, the old and original culvert was made of metal and though it was structurally intact, the integrity of its base was corroding, causing it to sink. A depression was forming over it on Route 90, which prompted the DOT to get the project under way. Other bidders for the job, which was awarded to Sargent Sept. 9, included Pike Industries, Inc., with a bid of $512,931, and Emery Lee and Sons, Inc., for $390,060.

The project is officially labeled the Rockport Strut Replacement and is expected to be finished by Oct. 4. Until then, traffic in that short section of the road will be down to one lane, which gives plenty of time to observe progress. The culvert pipe pieces are manufactured by Strescon, Ltd., in St. John, New Brunswick.

Reach Editorial Director Lynda Clancy at lyndaclancy@penbaypilot.com; 706-6657.