Contacts
 



Keyword Site Search










Vermont's Wandering River

by Stephen Kelly, regional editor






Vermont is a small gem in our midst. The state has the highest ratio of cows to people in the union and declared milk its official beverage. The sugar maple is the Vermont state tree. The state capitol (Montpelier) is the smallest in population (fewer than 9,000 people) and the only state capital without a McDonalds, but is the largest producer of maple syrup in the U.S. And no, Ben and Jerry's is not the state's largest employer--it's IBM.


Our story takes place in East Bershire, Vermont (44.967 N, 72.768 W) in Franklin County, just southeast of Bershire, as opposed to West Bershire--lots of Bershires about these parts, named after Bershire County, Mass. We are talking about the northwest quadrant of the state--about as close as you can get to Canada without changing nationality.

I'm woefully uninformed about the great state of Vermont. My French language background tells me the state's name is of Gallic origin, "green mountain," minus the "t" in vert (green). I know the capital, thanks to that rampant pedagogic principle of yesteryear, "rote" learnin'. And I know that part of the Appalachian Trail cuts through the state, thanks to Bill Bryson's hilarious book on that subject, A Walk in the Woods. So I picture the Green Mountains, pretty fall colors and the occasional covered bridge.

I have "learned" more about Vermont, including such trivial gems as the state flower (red clover), bird (hermit thrush), tree (sugar maple), fish (brook trout, walleye pike), insect (insect? Yes, the honeybee), and song (Hail Vermont--I didn't think it would be "New York, New York.")

I particularly like that Vermont designates a state beverage. I image the debate in the state legislature: "Pepsi," shouts one rep. "No, Coke!" shouts another. "The un-Cola," chimes in another. Cooler, saner, heads prevailed, of course. This is Vermont, afterall. As cows once outnumbered people here and milk production remains the leading agricultural enterprise, milk was the consensus beverage.

States also like to trot out other vital statistics: population, income and property values, are especially telling. Several Vermont numbers impress me: The median house value in 2000 was $81,000. Now I know where I'll retire, although few people move to Vermont to contemplate their bellybuttons in the waning years, judging by the median age of residents--36.1 years. But that's OK, who wants crowds of retired folk like in south Florida? Speaking of far from the maddening crowd, the population of Bershire at the time of the 2000 census was 1,388--1,388! There are more people in line at my local Starbucks.





OVERVIEW
The Vermont Agency of Transportation is replacing Bridge #26 on Route 118 over the Trout River in Bershire, Vermont.

Existing concerns with the project reach include:

o loss of a stable morphology

o loss of bank vegetation and aquatic habitat

o constriction of flood flow, creating a significant flood hazard

These factors combine to severely deteriorate the fishery, recreational, natural resource and aesthetic values of the river.

The Vermont Agency of Transportation and Dufresne-Henry, in consultation with W. Cully Hession, PhD, PE, and Lori Barg, Msc., and in cooperation with the Agency of Natural Resources and the Army Corps of Engineers, are coordinating stream restoration work with the bridge work to stabilize the project reach, provide required level of sediment transport and re-establish a riparian buffer zone.



BENIFITS TO THE ENVIRONMENTS
o The new bridge will provide immediate relief from the existing constriction of the flood flow prism and reduce backwater effects, which in turn will reduce sediment deposition

o Stabilization of the channel upstream of the bridge, with consideration for fluvial processes and establishment of riparian buffers, will dramatically reduce lateral migration

o The abandoned channel area will be allowed to become flood plain to provide flood relief as well as creating riparian and wetland habitat

o A 50-foot riparian buffer will be established and protected by easements

o Low-tech, low-cost and low-maintenance methods of bank stabilization will be used instead of traditional "hard armor" techniques

o A three-year monitoring plan will be implemented.



BENIFITS TO THE PUBLIC

o Replacing the bridge will remove a structural public safety hazard

o The continued lateral migration of the Trout River will be alleviated, thereby removing the possibility of future impacts to Route 118

o Future flooding hazards will be avoided

o Adjacent property will be protected by providing a planform that is geometrically concurrent with regime theory and reference section values

o The long term solution to channel stability will allow for reduction of costs associated with management of the Trout River.

Down to Business

Dufresne-Henry, of North Springfield, Vermont, which specializes in environmental engineering and has expertise in municipal utilities, transportation infrastructure, stormwater systems, private development, landscape architecture and planning, joined a team that included the U.S. Army Corp of Engineers and the U.S. Fish and Wildlife Service. The role of Dufresne-Henry was to facilitate public meetings, coordinate and manage project activities and provide assessment of the Trout River, including natural channel design and construction monitoring services.

The Trout River is formed in Montgomery by several branches. It runs in a northwest direction and falls into the Missisque on the border of Enosburgh and Bershire. Picture a mill stream and tributaries over considerable tracts of country. The Trout River's erratic movement over the past few decades in East Bershire has gobbled acres of valuable farmland. Without a project to stabilize the stream, there was just no telling what that unruly river would do. Sounds like the problem faced by parents of teenagers.






A 1995 aerial survey of the "wandering" Trout River (below) and for the years 1941, 1958, 1969, 1974, 1979, 1986. The river is formed in Montgomery by several branches and runs in a northwest direction.









Two unrelated man-made acts appeared to be the cause of the river's migratory inclinations. Foremost was the construction in the 1940s of a state highway bridge over the river. Bridge No. 26 on Vermont Route 118 is an aging, two-span bridge that rests on a central pier located in the middle of the Trout River. The bridge's slanted angle across the river, with its narrow opening and its in-stream pier, constricts the river's natural channel, creating problems during high flow periods. Constriction of the waterway at the bridge causes the river to back up and dump its sediment load upstream. As water levels drop, accumulated sediment forms large gravel bars and the river is pushed laterally, forcing it to cut new channels.

The other factor causing the river to wander was the removal of mature vegetation along the river banks by farmers who sought to maximize their agricultural lands. Root systems, of course, provide streambank stability and leafy vegetation slowed the erosive velocities of the river. Lack of a vegetated buffer to help define a channel and confine the water have allowed the river to seek new routes through the pastures of one East Bershire farmer.

Dufresne-Henry believes the project plan strikes a balance: replacing the bridge with one that does not impede the flow of the river and "restoring the river using natural channel design techniques that are wildlife friendly, environmentally appealing and self-sustaining."






The main cause of the river's migratory inclinations was the construction in the 1940s of Bridge No. 26 over the Trout River on Route 118. The aging, two-spaned bridge rests on a central pier in the middle of the river. The bridge's slanted-angle across the river and its narrow opening constrict the river's natural channel and creates problems during high water periods.


Vermont Agencies Tackle the Problem of a Wandering River

Vermont's Agency of Transportation may not have the power to move mountains, but it is working on an ambitious project to redirect the wayward.

Enter the Vermont Agency of Transportation (VTrans), which plans to replace its old bridge with a more river-friendly structure, and the Vermont Agency of Natural Resources (VANR), which governs any efforts to alter Vermont waterways. Their joint goals:

o Restore aquatic habitat, riverbank and wetland functions, and aesthetic and recreational value

o Restore channel stability to return needed sediment transport capacity

o Preserve local property

o Protect the bridge and adjacent roadway

o Prevent or reduce avoidable damage due to flooding

"VTrans," says Glenn Gingras, an environmental specialist with the agency, "faces many tough choices when designing and building projects. We have to balance the built and natural environments, while providing safe transportation for the traveling public."






The project goals of the Vermont Agency of Transportation to restore the aquatic habitat of the Trout River and the agencies involved.

View Full Size Image


Enter still other project stakeholders, including the U.S. Army Corp of Engineers, the U.S. Fish and Wildlife Service, the U.S. Department of Agriculture's Natural Resource Conservation Services, the Missisquoi River Basin Association and the affected landowners. And finally, enter Dufresne-Henry--who joined the team to facilitate public meetings, coordinate and manage project activities, and provide river assessment, natural channel design and construction monitoring services--and river experts Dr. W. Cully Hession and Lori Barg. Dr. Hession, a University of Vermont professor, hopes to involve students in the project as well.






Well rooted trees and a mature bank vegetation here keeps the river on course. However, the Trout River's erratic movement over the past few decades in East Bershire has gobbled acres of valuable farmland.


Through a decade of study, planning and design the project has been thwarted by continued migration of the river, landowner concerns, and the complexity of meeting all of the stakeholders' requirements.






he Trout River upstream is marked by lateral migration. Straw wattles and stone help direct the river. Low-tech, low-cost and low-maintenance methods of bank stabilization (such as straw wattling) is being used instead of traditional "hard armor" techniques.


"It's been challenging to complete the design within the original schedule with all of the planning and stakeholders involved and be able to adequately address all of the stakeholders' concerns," says DH Project Manager Scott Rogers. "From the landowners to the permitting agencies, everybody has a different view of what the project should be. Then things are complicated by the fact that the way the river moves, your survey data is inaccurate by the next spring runoff."






Constriction of the waterway at the bridge causes the river to back up and dump its sediment load upstream. As water levels drop, accumulated sediment forms large gravel bars and the river is pushed laterally, forcing it to cut new channels.














he other factor causing the river to wander was the removal of mature vegetation along the river banks by farmers. Lack of a vegetated buffer to help define a channel and confine the water have allowed the river to seek new routes through the pastures of one East Bershire farmer.


In spite of those challenges, a project plan has been completed that successfully addresses the diverse requirements of the many involved parties.

The plan strikes a balance that will replace the bridge with one that does not impede the flow of the river--and one that will restore the river using natural channel design techniques that are wildlife friendly, environmentally appealing and self-sustaining.

The channel will be reconstructed in a form that historically has been stable. Grasses, shrubs, trees, root wads and carefully placed rock structures will help protect the new channel while allowing it to move water and sediment at a rate that maintains the stability of the system.






"From the landowners to the permitting agencies, everybody has a different view of what the project should be," notes Dufresne-Henry Project Manager Scott Rogers. Then things are complicated by the fact that the way the river moves, your survey data is inaccurate by the next spring runoff."







This channel area will be abandoned and become a flood plain, as well as creating riparian and wetland habitats. A new channel will be constructed to handle the water and sediment flow. Grasses, shrubs, trees and rocks will stabilize the banks of the new channel.


Dufresne-Henry
Dufresne-Henry consistently ranks among the "Top 500 Design Firms" and "Top 200 Environmental Firms" in the country, as designated by Engineering News Record magazine. The firm specializes in environmental engineering, with expertise in municipal utilities, transportation infrastructure, storm water systems, private development, landscape architecture and planning.

With 50 years in the business, the company has developed a network of 17 regional offices, from Maine to Florida, to provide its services to a diverse client base. The varied educational backgrounds, work experience, and professional licensure of the 300 staff give the company a breadth and depth.

On Sept. 9, 2005, the Vermont chapter of the American Society for Landscape Architects awarded Vermont landscape architecture and engineering firm Dufresne-Henry with five awards for 2005, including one of the competition's highest honors. The firm's project to redesign and revitalize an inner-city playground in Boston received an overall Award of Excellence. Merit awards were given to four other Dufresne-Henry projects, including a project to redevelop polluted wetlands into athletic fields at Wellesley College, the recovery of an abandoned historic park and the revival of the large port area in Rochester, New York, and the revitalization of the downtown area of Batavia, New York.

Principal: Greg Edwards, vice-president Dufresne-Henry, South Burlington, Vt.



Related Stories




December 15, 2019, 8:30 am PDT

Website problems, report a bug.
Copyright © 2019 Landscape Communications Inc.
Privacy Policy