Connecticut River Coordinator's Office
Northeast Region
Yokum Brook in Becket, MA - Photo credit:  U.S. Fish and Wildlife Service
Yokum Brook in Becket, MA. Credit: USFWS

Currently, there are thousands of dams on the Connecticut River main stem and its tributaries. The first dams were log sluice dams used to float timber downstream. With the onset of the Industrial Age, dams were built to supply energy for sawmills, gristmills, and other industry. In 1798, the first full dam was constructed across the main stem of the Connecticut River near Turners Falls, MA. This dam contributed to the extinction of Atlantic salmon in the Connecticut River.

Deerfield River #2 Dam. Credit: USFWS  
Deerfield River #2 Dam. Credit: USFWS  

Over time, the number of dams have increased to support the growing population. Visit the following page to view dams constructed in the Connecticut River watershed over time.

Dams prevent fish from reaching upstream spawning and nursery habitat. They also slow down and prevent fish migration to the ocean. In these ways, dams contribute to declines in fish populations.

Dams destroy and degrade stream habitat, and obstruct fish access to important habitat.


". . . salmon were plenty until about 1798, when a dam 16 feet high . . . extending . . . across the river was built . . . just below the mouth of the Miller’s River . . . the fish ascended the river as far as the dam and the first year were taken in great numbers . . . the following year they were still plenty . . . at the end of four years they had nearly all disappeared."

-4th Report of the Commissioners of Fisheries of the State of Connecticut for 1870

Why are dams a problem?

Dams change stream character by:

  • Altering river flows and decreasing water quantity and quality downstream affecting aquatic animals

  • Altering water temperature

  • Increasing sedimentation (silt, sand, gravel) behind dam

  • Turning river into a series of lakes favoring non-native species

Dams are obstacles to fish movement in a stream:

  • Preventing fish from getting upstream to spawn

  • Preventing or delaying migration downstream

  • Preventing movements of resident fish within a stream

Dams pose safety concerns

  • Aging infrastructures can be hazardous to recreational boaters and downstream homeowners

Dams impact recreation

  • Require portaging of canoes, kayaks, and other boats

  • Impact angling opportunities

Solutions to Dams


Last updated: February 23, 2016
Connecticut River Coordinator's Office
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