Spectacularly, crews start chipping at dam
MERRIMACK – The Souhegan River will never be the same. Or, maybe more accurately, it will soon be the same as it was long ago.
Two men from Costello Dismantling using a bucket loader and hydraulic hammer made a huge gash in the east side of the Merrimack Village Dam on Wednesday morning, letting a torrent of water dash itself against the dam’s apron and continue downstream.
The initial breach is part of a five-week demolition that will remove the century-old dam to improve the river’s water quality and its potential as a fish habitat. The dam has long been unused and is being demolished partly because its upkeep is too expensive.
While the bucket loader scooped huge chunks of rock and piled it on the bank, the hammer gently pulled enormous, roughly 15-ton granite blocks, from the top of the dam, removing the top third of the structure.
The project has drawn plenty of attention, from crowds on the bridge to the Smithsonian Institution.
Sarah Waters, the senior communication coordinator for NOAA’s Habitat Program, was there with a film crew taping a documentary for the Smithsonian’s National Museum of Natural History.
The scene will be part of an interactive documentary titled “Open Rivers, Healthy Fish” that visitors to the museum can watch at a kiosk in the museum’s Ocean Hall, which opens Sept. 25, Waters said.
The demolition had already been delayed 10 days because frequent showers had raised the water level, according to Mike Costello of Costello Dismantling. Crews started earlier than scheduled Wednesday for fear the rain would delay the work again, he said.
The work on the dam, which is next to the Merrimack Central Fire Station, was visible from Route 3. A number of people stopped to watch despite the constant rain.
Tom Laberge, a Merrimack resident, stopped by with his church group. They had been watching the project over the past few weeks.
“We just wanted to come down and see. It’s not something you see every day,” Laberge said.
The removal of the dam will open 14 miles of river between Merrimack and Milford, which has two dams. It will also drain much of a swampy area behind the fire station.
“Ecologically it’s a huge benefit,” said Deb Loiselle, coordinator of the state Department of Environmental Services’ Dam Removal and River Restoration program.
The dam is located about a mile from where the Souhegan meets the Merrimack River. The first dam heading upstream on the Souhegan, it blocked fish that spend most of the year in the Atlantic Ocean from going upstream to their freshwater spawning grounds.
There are two dams on the Merrimack River downstream of the Souhegan – in Lawrence and Lowell, Mass. – but they have fish ladders, a series of small steps fish can jump over to make their way upstream, Loiselle said.
Eric Hutchins, the NOAA’s Gulf of Maine habitat restoration coordinator, said opening the natural course of the river could have a huge impact on the number and type of fish in the river.
The water will be cooler, he said, making it a better habitat for trout. Species like Atlantic salmon, Blueback herring and American eels, which make their homes as far away as Bermuda, the Carolinas and coast of Greenland, will be able to make their way as far inland as Milford, he said.
There will also be much more oxygen in the river and less algae and vegetation, Hutchins said.
“It’s going to probably be a beautiful stretch of bedrock, pools and ripples,” he said.
A dam has been located on the site since the 1730s to power a gristmill, sawmill and later a shoe factory, according to the script for Waters’ documentary. The current dam is much more recent: The concrete spillway was built in the 1930s.
Pennichuck Corp. bought the dam in the 1960s and first sought to use the impoundment area as a fresh water source. Following a letter of deficiency from the state in 2000, the company decided to remove it, Loiselle said.
When the water level started its 4-foot drop Wednesday, Hutchins was part of a 10-person team that scoured the banks upstream trying to save thousands of mussels stranded on the newly-created sandbars.
Volunteers gathered an estimated 10,000 mussels in 5-gallon buckets and moved them to deeper waters 500-1,000 feet upstream, he said. That work will continue today and on several Saturdays in the coming weeks.
Those volunteers will also clean up the garbage the lower water level exposed, including lounge chairs, glass and mailboxes, Hutchins said. He also spotted at least 10 old tires yesterday and expects to find many more when the dam is completely removed.
NOAA is charged with protecting the nation’s fish population, Waters said, a population that creates 28 million jobs and $30 billion between the commercial and recreational fishing industries.