A favorite Massachusetts stream loses a dam – and gains aquatic habitat
This post originally appeared on National Geographic’s Freshwater Initiative in Water Currents on March 6. Author Sandra Postel is director of the Global Water Policy Project, Freshwater Fellow of the National Geographic Society, and author of several books and numerous articles on global water issues. Funding for the Bartlett Rod Shop Company dam removal came from a variety of sources, including our agency, a natural resources damage settlement with Holyoke Coal Tar, Mass Environmental Trust, FishAmerica Foundation/NOAA Partnership, Clean Water Action and American Rivers/NOAA Partnership. The natural resource trustees for the Holyoke Coal Tar settlement consist of MassDEP, NOAA, and our agency.
In early January, on a visit back to my old stomping grounds in western Massachusetts, I trekked along the snowy banks of Amethyst Brook, a beautiful headwater tributary in the Connecticut River watershed. My mission was to see the site of a dam removed in late 2012.
I’d hiked through this area in the towns of Amherst and Pelham many times before, but had never sought out the stretch of stream blocked by the structure known as the Bartlett Rod Shop Company Dam, after the fly rod manufacturer who began operating alongside the stream in 1864. The dam itself – a 20-foot (6-meter) tall, 170-foot (52-meter) wide rock structure – had blocked the brook since 1820.
Over the decades, the mill had transitioned through many uses, including a woodworking shop, a machine shop, a maker of boiler tube cleaning equipment, and finally to HRD Press, a provider of products and services for human resources development. While the company owned the dam, it didn’t need it.
After receiving a dam safety order from the state in 2007, HRD Press began working with government agencies and conservation groups to study the idea of taking the obsolete dam down. In 2010, Massachusetts officials named the dam’s removal a priority project for river restoration – and by late 2012, thanks to a broad partnership of federal and state agencies, the two towns, and conservation groups, the dam was dismantled.
In the months since, Amethyst Brook has begun to heal.
Freed by the dam’s removal, sediment has moved downstream. So has organic matter in the form of leaves and woody debris, critical to aquatic food webs. Water temperature has dropped, and oxygen levels have increased.
With the dam gone, trout can now move further upstream to high-quality coldwater habitat.
And below the dam site, a stream bottom of gravel and cobbles has formed – habitat just right for the spawning of the migratory sea lamprey.
A snake-like fish, the sea lamprey (Petromyzon marinus) migrates from the ocean to freshwater to reproduce. In the Connecticut River system, the fish moves upstream from Long Island Sound in Connecticut, passes Holyoke Dam in Massachusetts with the help of a fish lift, and then travels further north and into side tributaries in search of spawning grounds.
After depositing eggs and milt (sperm) in a protected nest of stones, the adult fish die. About two weeks later, the eggs hatch. The larvae then drift downstream and burrow into a sandy stream bottom. Young sea lamprey will remain in the river system for up to ten years before heading back to the ocean. After a year or two at sea, it will head up river to spawn, completing its life cycle.
Just six months after the Bartlett Dam was demolished, conservationists were thrilled to find sea lamprey spawning in Amethyst Brook, just below the old dam site.
Seeing this native fish spawning was “a great sign of improving conditions in the river,” writes Amy Singler, associate director of river restoration with American Rivers, one of the conservation partners involved in removing the dam. …Keep reading this post at NatGeo!