Dealing with Dams and Culverts
To many people, “fish passage” means salmon migrating upstream to their spawning grounds and downstream out to sea. There’s more to the story. American shad and river herring (both alewife and bluebacks) once came up and down the Farmington by the tens of thousands too, and some still make the attempt. American eels and sea lampreys still make the journey every year also. Even local fish like trout and dace need to travel freely within the river to find good habitat. Many more animals—reptiles, amphibians, and mammals—need free passage along the edges of rivers and streams to in order survive and maintain healthy populations.
There are literally hundreds of barriers in their way, either old dams or culverts where streams pass under roads.
At FRWA, we work with many partners to remove these barriers.
Dam Removals and Retrofits
The upper reaches of the Farmington offer abundant spawning habitat to migratory fish, but the habitat is under-used because of dams that block upstream passage. Not every dam can be removed– but FRWA is actively engaged in dam-related projects that would provide real benefits to fish and people.
Spoonville Dam – Engineering Plan for Fish Passage
Design. In 2009, FRWA received funding from the State of CT (from polluter restitution payments) to coordinate an engineering study of the old Spoonville Dam in Bloomfield/East Granby. The dam, breached in 1955, pinches the river’s flow to a narrow, fast current that blocks upstream passage for migratory fish such as shad, alewife, and blueback herring as they return from the ocean and swim upstream to spawn. The engineering study concluded that the best way to restore fish passage would be complete removal of the dam, and it provided the design for removal. (Engineering study is available upon request).
Benefits of Removal.
- River flow rates that once again allow American shad, alewife, and blueback herring to swim up through Tariffville Gorge and access more than 20 additional miles of river.
- Improved safety for boaters and swimmers.
- A restored scenic waterfall in place of a derelict dam at a popular fishing site.
Stakeholders. The towns of East Granby and Bloomfield endorse removal. The whitewater paddling community benefits from Tariffville Gorge (just upstream of the dam) as the venue for world-class whitewater paddling events. The engineering study demonstrates no adverse impact of dam removal on the whitewater paddling run, except of course losing the chute through the dam breach. The gain in boater and swimmer safety was seen as offsetting the loss of this whitewater play feature. The dam owner, CT Light and Power (a subsidiary of Northeast Utilities) supports removal.
Funding. Removing Spoonville Dam is a big job—breaking up and removing about 2,000 cubic yards of concrete from the bottom of a ravine—and is estimated to cost between $1 million and $1.5 million. To date (2011), FRWA has raised almost half the funds, and is well along in permitting the project.
Winchell Smith Dam—Engineering Plan for Fish Passage
The Winchell Smith (or Grist Mill) Dam in Farmington presents a barrier to fish passage in some low water conditions. In 2009, FRWA received funding from the State of CT for an engineering design to improve fish passage at this site. Because the dam is of historic interest and a popular scenic feature, the design for fish passage does not entail dam removal. Instead, the design is for a natural looking stepped rock ramp that will allow fish to pass over the top of the existing dam.
Whenever resources become available for implementing the engineering design, the finished project will improve fish passage as far as Collinsville on the Farmington mainstem.