Environmental Review Toolkit
Water, Wetlands, and Wildlife

mitigation site after wetlands are established
Pine Road Mitigation Site Post-establishment
mitigation site before wetlands are established
Pine Road Mitigation Site Pre-establishment
arial view of mitigation site after wetlands are established
Pine Road Mitigation Site Post-establishment - Arial View
arial view of mitigation site before wetlands are established
Pine Road Mitigation Site Pre-establishment - Arial View

New Hampshire Department of Transportation

Route 101 Ecological Protection and Enhancement Features

It's not every day that science students from local colleges and high schools use a State-developed wetlands site for an outdoor laboratory.

At the 320-acre Pine Road Wetlands Mitigation Site created by the New Hampshire DOT (NHDOT) - the largest site of its kind in the State - the students have come to study water quality and other typical wetland functions. The mitigation site is part of a completed project to improve a nearby 17.6-mile stretch of Route 101, especially a narrow, two-lane section known as "the Gap." The Gap had not been upgraded in 60 years and was the scene of frequent accidents, many of them serious.

Local residents were concerned about the potential impact of road improvements on their homes, businesses, and historic properties, and environmentalists wanted to make sure that impacts to local wetlands and other wildlife habitat were avoided. Controversy over the alignment led to a Governor's Task Force to guide project development.

Once a new alignment was selected and under the guidance of the Task Force, NHDOT developed a mitigation strategy that focused on a broad "landscape approach" to fit local ecosystem and resource management needs.

Existing culverts on the Piscassic River were replaced by a twin-span bridge, which provided an improved hydraulic structure and a better corridor for wildlife movements across the highway. Four acres of salt marsh were restored when a bridge over the Squamscott River was lengthened by 560 feet. The historic 230-acre Connor Farm and 70 additional acres near the Pine Road site were purchased to allow wildlife passage from the farm to the Pine Road site. And under the watchful eye of an interdisciplinary team of representatives from State and Federal agencies and local groups, more than 100 acres of freshwater wetlands were created and enhanced at the Pine Road site (the biggest wetland-creation project ever undertaken by NHDOT).

At Pine Road, scientists studied wells on the site for 3 years before construction to record the fluctuations of the water table. They designed the site to promote diverse plant communities, creating a "mound-and-pool" microtopography. This landscape feature resulted from alternately raising and lowering a bulldozer blade to make depressions for standing water and small mounds for drier areas. The scientists also installed a special irrigation system to ensure the survival of new plantings during the first year, and they took aggressive measures to control the infestation of purple loosestrife, a noxious weed.

That's not all. In the wetland-creation process, work crews "recycled" 1.2 million cubic yards of sand and gravel for use on the Route 101 project!

Today, Pine Road is a mosaic of 145 different plant species attracting wildlife ranging from ducks to herons to moose. It has been a field-trip site not just for students but also for scientists from the National Association of State Wetland Managers. This site is the focal point of an ambitious mitigation package which has protected and enhanced a variety of ecosystem resources important to the regional landscape while at the same time enabling a much-needed transportation improvement.

For more information, contact Den Danna at ddanna@dot.state.nh.us.

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