UMass Amherst Research to Identify Northeast River Corridors

A river corridor.
“By mapping the swath where the river would move freely across its natural floodplain, we provide the best available information about where water has potential to be damaging, and places it is unlikely to cause problems,” says UMass Amherst geoscientist Christine Hatch.

AMHERST, Mass. – Geoscientists Christine Hatch and John Gartner at the University of Massachusetts Amherst have received a two-year, $99,000 grant from the North Atlantic Landscape Conservation Cooperative to help create a regionally consistent assessment of river corridors across the North Atlantic states.

As Hatch explains, the work will focus on delineating a river’s corridor, “an area typically much wider than what we think of as a river and significantly wider than bank-to-bank,” which represents its “true area of influence.”

Rivers tend to move over time within this corridor, and this natural river migration process can include the erosion of streambanks, which may damage infrastructure and property. River erosion is one of the most costly and common sort of flood damage, with floods ranking among the most deadly and expensive natural hazards.

Floods are expected to increase in the inland northeast region due to climate change, the researchers say. Hatch, whose long-term research interests include how to be “river-smart,” says that in addition to sea level rise, Massachusetts has a couple of other major vulnerabilities with future climate change: more rain and more intense rain. This means larger and faster river flows with a higher potential for flood damage.

“Our regional study group will be coming up with recommendations and best practices on how to use river science to inform our designation of flood hazard zones and areas of ecological value. We’re going to try to do this with consistent methodology on a broad scale across the whole North Atlantic region,” she says. “By assessing river-adjacent lands more thoughtfully, we can also address climate change and how it is expected to affect rivers.”

Hatch adds, “By mapping the swath where the river would move freely across its natural floodplain, we provide the best available information about where water has potential to be damaging, and places it is unlikely to cause problems.” Once river corridors are delineated in a way that is consistent regionally and across state lines, people can plan and build in ways that can dramatically reduce erosion and other hazards associated with river floods.

Across the region at present, many different definitions are used to describe and delineate riverside areas. “In Massachusetts, we have the Wetlands Protection Act with setbacks designed to protect streams and riparian areas,” she says. “But a problem is that the setbacks are uniform and do not incorporate healthy river movement, and in that sense, they are not science-based at the site-specific scale.”

Hatch says, “The Vermont Rivers Program has been a fantastic partner from the inception of this project. Not only have we learned from Vermont’s comprehensive assessment program known as SGAT, stream geomorphic assessment tool, we’ve also benefited from the generosity of the program’s director Mike Kline, who has shared his advice, time and experience with our Fluvial Geomorphic Task Force since 2012.” She, Gartner and others will use test areas as models that can be applied to rivers from Virginia to Maine.

Results of Hatch and colleagues’ work will become part of a landscape design tool that will allow users to overlay river corridor information onto other information such as priority habitat, cultural resources, culverts in need of repair or replacement, vulnerable infrastructure, homes or properties or lands available for environmental conservation.

They hope this information may help to guide future management. “In the long run, placing homes, buildings and roads farther back from where rivers naturally move will save money and lives while preserving infrastructure and the ecosystem,” Hatch notes. “This also provides a place for floodwaters to go, making the land downstream less vulnerable to future flooding.”

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