culvert newsletter 3 - the nature conservancyculvert operations: assessing aquatic continuity in the...

Culvert Operations:Assessing Aquatic Continuity in the Ashuelot Watershed


A (very) little stream ecology

Eastern brook trout and other aquatic life

Needs access to up- and downstream habitat for spawning, feeding, refuge

Needs cool, clean and well-oxygenated water


Other organisms that need up- and downstream access:• Shad, herring, Atlantic

salmon, American eel

• Mussels

• Turtles

• Invertebrates

• Mammals


stream crossings:

Where roads, railroads, bridges, and dams cross streams


culverts:

When it comes to aquatic connectivity, some culverts

work well.

They let water flow under roads and allow fish and other organisms to move

freely up- and downstream.


Other culverts don’t work so well.

They block the movement of fish and other organisms to

up- and downstream habitat.!!

culverts:


Natural flow of streams and tributaries

Graphic: Scott Jackson, UMass.


Road-stream crossings



Road-stream crossings that block upstream

tributaries.



Understanding aquatic continuityat the watershed scale

Ashuelot River watershed in southwestern N.H.

• 425-square miles

• 1,039 road-stream crossings

• ~ 150 river and lake dams


Understanding aquatic continuityat the watershed scale

“The Ashuelot supports lots of our top priority species, including Atlantic salmon and American shad. These fish have traveled from the ocean to breed, so we’re trying to make sure they have high quality habitat for spawning.”

- Doug BechtelTNC Director of Conservation Science, NH Chapter

Doug Bechtel at site of removed dam in Winchester, N.H.


“Culvert Ops”

Goals:• Assess aquatic “continuity &

fragmentation” in Ashuelot River watershed;

• Assess physical features of road-stream crossings and dams;

• Rank which culverts are the biggest problem for wildlife and ecological processes;

• In long-term, restore fragmented habitat.


Funding:• N.H. DES Watershed

Assistance Grant;• Moose Plate;• U.S. Fish & Wildlife

Service


Protocol:• Adapted from Mass.

River & Stream Continuity Partnership

• Rigorous peer-reviewed standards by EPA

Field form


Field Assessment:• 80 + Volunteers• Coordinated by Ashuelot

Valley Environmental Observatory;

• Assessed 663 Bridges and Culverts


Dams:Nature Conservancy intern

Kate Kerivan assessed 128 dams in the watershed


Culverts/Bridges Results:• Severe Barrier: 20%• Moderate Barrier: 56%• Minor Barrier: 20%• Passable: 4%


Dam Results:91% Barriers


Which culverts, if replaced, would restore the most miles of high-quality stream habitat?

*GIS Analysis:• Stream miles• Upstream watershed water quality• Up/downstream buffer habitat quality

* GIS: Geographic Information Systems


Setting Priorities/Restoring Streams:Identifying crossings to restore habitat


Next Steps:Working with Southwest Region Planning Commission and local

communities on restoration plans for priority crossings.

Mass. Riverways Program. – http://www.mass.gov/dfwele/river/pdf/stream_crossings_handbook.pdf


Photo by Jerry @ Marcy Monkman / www.ecophotography.com Other photos by Scott Jackson, UMass; Ashuelot culvert volunteers; TNC staff

culvert newsletter 3 - the nature conservancyculvert operations: assessing aquatic continuity in the...

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