Compensatory mitigation: An attempt to even the scales of environmental impacts

It’s a way of offsetting construction impacts to wetlands and other aquatic resources
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The Shelburne Valley Forest stretches from the shoreline of the Androscoggin River to the ridgeline of the Mahoosuc Range. (Courtesy of Ryan Smith)

Where Route 16 winds north along the Androscoggin River, passing through the towns of Dummer and Errol, forests of northern spruce and fir trees surround the remote, rural roadway. There are large swaths of palustrine wetlands, like bogs, swamps, and marshes, that are heavily vegetated with winterberry, nannyberry, goldthread, and bunchberry.

One of two major north-to-south corridors in the North Country, Route 16 has been identified as a regional priority in the Berlin-Gorham socioeconomic center – vital for tourism, outdoor recreation, logging, manufacturing, and other industries.

The state Department of Transportation is making improvements to it – specifically a 1.3-mile stretch in the township of Cambridge. The pavement is in poor condition and there’s no structural base under the roadbed. When the section in question was constructed in the late 1950s and early ’60s, it was never formally designed.

More than 230,000 square feet of palustrine wetlands and stream channels will be impacted by the infrastructure project – a cost and reality of living in a built environment where humans use roads to get where they’re going, said Kevin Nyhan, administrator of NHDOT’s Bureau of Environment.

But at both the state and federal levels, there are laws aiming to even the scales of environmental impacts. It’s a concept called compensatory mitigation, included in Section 404 of the federal Clean Water Act.

Making up for wetlands impacts

Wetlands have vital functions and values, including flood storage, erosion control, nutrient retention and water quality improvements, and species diversity.

In 1989, President George H.W. Bush established a national goal of “no net loss of wetlands,” the idea that if wetlands are lost in one place, they should be preserved, restored, or enhanced in another. The approach has been evolving since.

At its crux, compensatory mitigation is the attempt to offset unavoidable impacts to wetlands or other aquatic resources resulting from a permitted activity like roadwork or building construction. Under New Hampshire’s laws and regulations, parties seeking to construct projects that affect wetlands to a certain extent (10,000 square feet or more) must provide mitigation.

They’re required to make up for the losses somewhere else, either through an in-lieu fee payment or by identifying a local opportunity to “do good.”

In the case of the NHDOT’s Route 16 project, the department was able to identify a rare local opportunity – the chance to help preserve in perpetuity a 2,670-acre property known as the Shelburne Valley Forest, down river from their anticipated impacts. The national nonprofit Conservation Fund and Society for the Protection of New Hampshire Forests have been working toward permanent protection of the land, which stretches from the shoreline of the Androscoggin River to the ridgeline of the Mahoosuc Range, for several years.

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A Department of Transportation project on Route 16, which runs adjacent to the Androscoggin River, will have wetlands impacts. The department is required to provide compensatory mitigation to make up for the impacts elsewhere. (Courtesy of NH Department of Transportation)

NHDOT’s contribution of $1.25 million, the assessed value of its wetland impacts, makes the land conservation nearly complete.

“We’re in the business of balancing our impacts with trying to preserve, protect, and create as many of these resources as we can,” Nyhan said. “Wetlands, streams, and rivers, archaeological sites, historic properties. Oftentimes we find ourselves trying to thread the needle with improvements we want to do.”

The ARM Fund

The state’s Department of Environmental Services oversees compensatory mitigation and administers the Aquatic Resource Mitigation Fund, in which all in-lieu fee payments are pooled by watershed location to later be disbursed as competitive grants for significant restoration and conservation projects.

Payments reflect the cost to construct a wetland of the size in question, along with land values and current interest rates, said Emily Nichols, manager of the ARM Fund Program. She noted the state’s “mitigation hierarchy is shifting” to better align with federal requirements. Permittees used to be encouraged to identify a local mitigation project first, but now an in-lieu fee payment is often the favored option.

The U.S. Environmental Protection Agency says in-lieu fee programs “are an extremely effective regulatory tool for protecting and restoring aquatic resources while allowing for the growth of the economy through development projects.”

“Us giving the money to DES really puts it in the hands of the people who do it the best,” said Nyhan. “They’re able to take our money, pool it with other money, and do bigger and better projects.”

Arm Funds Map

A map from the NH Department of Environmental Services shows what watershed areas received Aquatic Resource Mitigation Fund grants in 2022.

Since 2007, the ARM Fund has awarded more than $35 million across 141 mitigation projects statewide, conserving 28,078 acres of land, 4,047 acres of wetlands, 117 miles of stream, and 422 vernal pools. Dozens of projects have also enhanced aquatic habitats for fish passage via dam removals and culvert upgrades, as well as restored salt marshes and oyster reefs.

In recent months, the fund awarded more than $200,000 to remove a dam on Brennan Brook in Francestown where wild trout are a “high priority population” for restoration efforts. The project will reestablish stream connectivity, improve passage, and restore surrounding wetland systems.

In Atkinson, ARM funds are being used to conserve a 15-acre parcel within the Merrimack River Service Area, adjacent to the West Sawmill Town Forest and containing “high-functioning vernal pools and upland buffers providing habitat for spotted salamanders, wood frogs, and Blanding’s turtles.”

And in Goffstown, $300,000 went to the Piscataquog Land Conservancy to purchase a 42-acre conservation easement that includes a portion of the third-largest prime wetland in the town.

Karl Benedict, a public works subsection supervisor at the Department of Environmental Services, said the state’s NHDOT is often “our primary mitigator.” According to NHDOT records, in fiscal year 2022, the agency paid $4.7 million to the ARM Fund.

DES sees impacts from all sorts of projects, though. In 2022, the redevelopment of a golf course and construction of a warehouse in Hudson merited an ARM payment, as did the construction of a senior living facility in Littleton and expansion of a sawmill in Grantham.

Both Nyhan and Benedict discussed how much back-and-forth comes before compensatory mitigation is agreed upon. The ultimate objective is not needing any at all.

“Our goal is to avoid and minimize as much as we can,” Benedict said. “As much as we value our ARM program, we do try to start with less impacts and try to only get there when we have to.”

‘About as good as it gets’

This year, a Stanford University-led study found the U.S. accounts for more wetlands loss than any other country. And a recent report by the EPA also detailed “considerable losses” to coastal wetlands in the past 20 years, “despite the efforts of both regulatory and voluntary (mitigation) programs.”

Compensatory mitigation is not a silver bullet solution. But there are many success stories.

Perhaps an exemplary case is the Department of Transportation playing a part in the preservation of the Shelburne Valley Forest. An alternative to the ARM Fund, if a local project is identified as a good mitigation match, the permittee can opt to “restore, enhance, or preserve” aquatic resources or land directly.

The Shelburne Valley Forest can be spotted from more than 6,000 feet up – when visitors take in the panoramic view at the top of Mount Washington. In that sense, said Jack Savage, it’s part of the fabric of New Hampshire’s scenic beauty.

Savage is the president of the Society for the Protection of New Hampshire Forests, one of the groups that’s been instrumental in the multi-year venture to permanently protect the 2,717-acre forest that runs adjacent to the Appalachian Trail. They’re nearly there, and the recent $1.25 million contribution from the NHNHDOT “almost seals the deal,” he said.

It’s part of a larger Mahoosuc Highlands initiative to protect both the Shelburne Valley and Bald Cap Peak forests. First up, with more than 1.6 miles of shoreline along the Androscoggin River, the Shelburne Valley Forest is home to cranberry bogs, red spruce swamps, silver maple floodplain forests, and talus slopes and cliffs. It has 24 miles of stream frontage and contains the headwaters of the Leadmine Brook.

The current owner has managed the land as a working forest for wood products. After the sale, the land will remain open to hiking, hunting, fishing, and for future forest management.

The compensatory mitigation arrangement with NHDOT, Savage said, “that’s about as good as it gets.”

“It was a good match because the (NHDOT’s) impact is on the Androscoggin and the project is just down the river, protecting a forest that has streams that feed the Androscoggin,” he said. “You want mitigation to be meaningful in the same place where there’s impact.”

This story was originally produced by the New Hampshire Bulletin, an independent local newsroom that allows NH Business Review and other outlets to republish its reporting.

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