Threatened or Endangered Wildlife at Risk Due to Hydropower on the Connecticut River (guest perspective)



The Connecticut River is home to many types of wildlife that move through the river and depend on parts of the river and banks during their life cycle. Tiger beetles hide on river beaches in sandy hiding places to hunt their prey. Ancient shortnose sturgeons migrate from the estuary to upstream areas and congregate at the bottom of the river in winter. Dragonflies live like larvae in water and emerge to develop into adults on the banks of the river each summer. Freshwater mussel larvae move through “host fish” and then settle in the sediment and filter the water during their adult life. These animals have been around for thousands of years and only in the last few hundred years have they been affected by the presence and patterns of hydroelectric facilities on the Connecticut River. Not surprisingly, many of them suffered and are now listed as endangered or threatened under federal or state law.

Five hydroelectric facilities on the Connecticut River are renewing their operating licenses under the Federal Energy Regulatory Commission (FERC). Later this summer, the public will have the opportunity to weigh in on the terms of these licenses that will impact more than 175 miles of the Connecticut River over the next 40 to 50 years. These facilities are the Wilder, Bellows Falls and Vernon Dams in Vermont and New Hampshire, as well as the Northfield Mountain Pumped Storage Project and the Turners Falls Dam.

The current operating patterns of these five hydroelectric facilities impact fish and other aquatic species in many ways, primarily through rising and falling water levels in addition to the obvious barrier of a dam to it. -even. All installations hold back some of the flowing water and then release it through turbines to generate power when needed and cost-effectively to do so – a process called “peaking”. This leads to constantly changing water levels upstream and downstream of these facilities.

Connecticut River dragonfly and damselfish species are listed as threatened or endangered in Massachusetts, Vermont, and New Hampshire in project areas. When ready to turn into adults, the larvae crawl out of the river to the shore, shed their larval bodies and unfurl their wings, which must dry and harden before they can fly. During this time, they do not move and are extremely vulnerable. If the water level rises or if a wave knocks them over in the water, they drown and die. The Puritan Tiger Beetles are threatened federally, and the Cobblestone Tiger Beetle is protected by state law. These beetles burrow in areas of sand or pebbles along the edge of the river. They can survive short periods of submersion in their burrows, but hydroelectric operations have permanently inundated some ancient habitats while submerging other areas almost daily. Fowler’s Toad is protected in New Hampshire and Vermont, and there is significant habitat downstream from Vernon Dam. This toad lays eggs in small pond areas along the river. Drying or flushing these small ponds can wipe out the eggs or tadpoles.

Rapid changes in river flow, when hydroelectric facilities suddenly release water, are also problematic. High velocity water can flush Shortnose Sturgeon eggs and larvae downstream from Cabot Station at the end of the Turners Falls Canal. The same can happen with young freshwater mussels before they become embedded in river sediments. The shadow that spawns under the Turners Falls, Vernon, and Bellows Falls dams is frightened when conditions change sharply. When their reproduction is interrupted, it can reduce the number of times a fish can spawn in its lifetime or reduce the number of young fish produced in a season.

The requirements of new hydroelectric licenses may cope with these impacts. Great River Hydro (GRH) worked with the Connecticut River Conservancy and other stakeholders to propose a radical change to their operations. They will shift most of the time to an equal inflow-outflow model of operations that will keep river water levels more consistent, with fewer small “peak” events allowed, depending on the season. FirstLight proposed to slow down the starting speed of the turbines or the speed of rising waters. However, rather than switching to a model like GRH, FirstLight still plans to operate the Turners Falls Dam and Northfield Mountain pumped storage in detrimental ways.

Anyone who cares about wildlife should get involved in defending the river later this year. Insist that FirstLight make better changes to its operations, as Great River Hydro has offered to protect our precious natural heritage species. Learn more about and talk to

CRC will summarize other elements of the license application in the coming months.

Andrea Donlon and Kathy urffer are the river stewards for the Connecticut River Conservancy.


Leave A Reply

Your email address will not be published.