Progress / Science

Mapping the Mighty Missisquoi

The Missisquoi is a gem of Vermont. From its alpine headwaters on Jay Peak to the federally-protected, waterfowl-filled delta on Lake Champlain, the Missisquoi dashes, then saunters through a landscape that is both quintessentially Vermont and uniquely rugged. The Missisquoi, whose name is derived from an Algonquian Abenaki word meaning place of large rocks, is approximately 88 miles long, of which roughly 25 miles meander through southern Quebec. For as long as people have lived in northern Vermont, this river has been a two-way passage for canoes, goods, and wildlife alike. As its longest upstream stretch, it is now a notoriously defeating reach of the Northern Forest Canoe Trail. Truly, one could spend a lifetime on the Missisquoi River.

But a river is not just a river – it is the mountains, valleys, and communities that surround it. In the case of the Missisquoi, the river is fed by approximately 1,200 square miles of ancient mountains, bucolic pasture, productive farms and forests, and importantly, wetlands. Wetlands are the sponges that soak up precipitation and slowly release it to the rivers, the filters that remove excess nutrients, and the nurseries that support many birds, amphibians, fish, and mammals. In essence, the communities of the Missisquoi River, natural and human, are dependent upon its wetlands. But in an area of 1,200 square miles, where are these crucial ecosystems?

The National Wetlands Inventory (NWI) estimates the Missisquoi Basin to be approximately 5% wetland by land area. This mapping from the NWI is 12-14 years old and proven to be coarse at best. A study from the University of Vermont and experience from the Wetlands Program show that at least 30% of our wetlands are unmapped by the NWI, suggesting that 6.5% of the Missisquoi Basin could be wetland. The Vermont Department of Environmental Conservation’s (DEC) Wetlands Program is tasked with protecting wetlands according to the Vermont Wetland Rules, but dated and inaccurate mapping can make this difficult. In 2018, with funding from the U.S. Environmental Protection Agency, the Wetlands Program set out to update the current mapping to better serve the public and the resource, starting with the mighty Missisquoi Basin.

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A large beaver-flooded conifer swamp at the headwaters to McGowan Brook, a tributary to the Missisquoi in Sheldon.

Mapping wetlands over a 1,200 square mile area is a tall order, but luckily DEC has new tools to employ, including LiDAR or precise topographic mapping shot from an airplane, Color Infrared (CIR) photography that can indicate tree species, and new aerial photos (as recent as summer 2018). These tools are in the hands of experienced consultants at St. Mary’s Geospatial Services in Minnesota, who can remotely “fly” around the state, identifying wetlands from their desk. As an environmental technician for the Wetlands Program, I was lucky enough to be these consultants’ eyes on the ground and minimize time at my desk.

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The author, DEC Wetland Technician Levi Keszey, surveys wetland plants, soils, and water quality to study the function and condition of Vermont’s wetlands.

For the month of October, I zipped around the wild, wild northwest of the state from Newport to Swanton, a vast area in which, despite having grown up in the Lamoille Basin, I had not spent much time. I went from manure pond to beaver pond and mountain seep to farm ditch. My task was to verify what St. Mary’s had remotely mapped, and to eat some creemees along the way. This is what I learned:

  • Culturally, the Canadian-Vermont border is a blur once the bulbous hills of southern Quebec are the skyline.
  • Beaver are thriving in the Northwoods, especially in culverts.
  • The hippest new fashion in Franklin County is a quilt that your barn wears.
  • There is delicious takeout fried alligator and catfish in Vermont (Cajun’s Snack Bar, North of Lowell).
  • And of course, there is a huge diversity of wetlands in the Missisquoi Basin, some pristine, some barely hanging on.

In addition to mapping the location of wetlands in the Missisquoi Basin, we are classifying each wetland according to the NWI+ standards, which types the sites according to the vegetation, water regime, substrates, and modifications such as beaver or ditches. This will make these data tremendously useful in modeling ecosystem functions like phosphorus capture and flood attenuation. This basin has been targeted with the highest phosphorus reduction goals of all the Lake Champlain Basin, and outdated mapping has kept us from knowing the full potential for wetland restoration –where it would work best and what benefits it could yield. Geospatial modeling of nutrient transport, as done in the Water Quality Blueprint by The Nature Conservancy, is an exciting new tool, and only one example of the type of fresh understanding of our landscape that can be achieved with such data.

The line between wetland and upland can be muddy. Even to wetland experts on the ground, wetland boundaries can be difficult to identify. DEC’s updated wetland mapping will not be perfect, and will never be as accurate as a boots-on-the-ground review, but this mapping will help landowners, town managers, and others in the Missisquoi Basin determine when they may need to seek further expertise.

The Missisquoi River is an icon that supports communities that represent the best of Vermont. The people who live there know this and we want to empower them with the  information and tools they need to protect the basin.

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DEC District Ecologist Brock Freyer mapping wetlands on a cold, wet day on the Missisquoi River.