Down with the Dam

Down with the Dam

Old dams are being taken down around the country for environmental and safety reasons. In Massachusetts, the story of the Upper Roberts Meadow Reservoir Dam removal project shows the complexities involved and the opportunities for engineers.

By Mary Serreze

From California to Maine, aging dams are coming down, providing opportunities for engineers interested in climate resiliency, habitat restoration, public safety, and green infrastructure. Since the United States hosts more than 90,000 sizable dams, many built 50 to 100 years ago and in poor shape, firms that develop capacity in the field of dam removal could be in line for a steady stream of work.

In 2018 alone, 82 dams were removed in 18 states, according to the advocacy group American Rivers. Since 1912, nearly 1,600 dams have been dismantled across the country in an effort to enable fish passage, restore riparian habitat, improve public safety, and reduce owner liability.

Throughout America’s history, dams supplied mechanical energy for grain mills, drove the machinery of the industrial revolution, generated hydropower for homes and businesses, and impounded reservoirs for drinking water, fire protection, flood protection, and navigation. Now, many such dams have outlived their usefulness and are often doing more harm than good.

While the ecological impacts of river impoundment are real, safety and liability concerns are driving many of today’s dam removal decisions. In a 2017 report card, the American Society of Civil Engineers gave the nation’s dam infrastructure a D grade and estimated the cost of fixing all U.S. dams in need of repair at around $64 billion. In many cases, owners have found that the costs of repair and maintenance exceed the cost of demolition.

Whether prompted by environmental, safety, or financial concerns, the most successful dam removal projects address multiple objectives and are advanced through collaborative relationships between owners, affected landowners, government agencies, river ecologists, and forward-looking engineering and construction firms.

Signature project took many years

The story of a small dam removal project in southern New England offers lessons for any engineering firm hoping to land such work. GZA GeoEnvironmental, headquartered in the Boston area, shepherded the project for more than a decade. In 2019, GZA won an Engineering Excellence Gold Award from the American Council of Engineering Companies for their work. The awards honor complex projects that deploy innovative techniques, address social or sustainability concerns, and add value to the engineering profession.

Built in 1883, the Upper Roberts Meadow Reservoir Dam initially impounded a six-acre drinking water reservoir for the city of Northampton, Massachusetts. Thirty-five feet tall and 125 feet long, the granite block dam featured a 65-foot, broad-crested, curved masonry spillway. For years, the structure stood as a solid example of late 19th-century New England engineering. The impounded reservoir, which eventually became shallow and laden with sediment, was fed by the Roberts Brook, a cold, clear stream sourced from a pristine forest.

By the 1970s, the reservoir was no longer in use, and the dam was suffering from decades of neglect. Even after it was rated by the Army Corps of Engineers as an unsafe structure in poor condition, the dam quietly remained as a picturesque asset of the city’s water department.

But everything changed in 2005 when a wooden dam in the city of Taunton, Massachusetts nearly failed during a period of heavy rain, forcing the evacuation of nearly 2,000 people. After the near-disaster, the Massachusetts Office of Dam Safety issued tougher regulations and ordered dam and levee inspections in every corner of the state.

Northampton hired GZA to evaluate its dams, and its engineers confirmed that the Upper Roberts Meadow

Dam was in poor condition and in a “high hazard” location, meaning that if it failed, loss of property and life would likely occur. The city owns a separate dam and reservoir a mile downstream, and GZA posited that under a worst-case scenario, a domino effect could result in a double failure, imperiling homes in the nearby village of Leeds.

State dam safety authorities promptly hit the city with a letter of non-compliance and ordered followup inspections every six months. The city was ordered to prepare a Phase II engineering evaluation, produce an emergency action plan, and come up with a solution. In short, the order created a two-pronged decision pathway for the city: either fix the upper dam, or tear it down.

Northampton again retained GZA, and the firm evaluated four options — no action, dam removal, dam modification, and full rehabilitation. GZA recommended removal, considering initial project costs, long-term maintenance costs, liability risk, potential for outside grant funding, fiscal impacts to water ratepayers, and the environmental benefits of stream restoration.

On April 3, 2008, Northampton’s Board of Public Works (BPW) took GZA’s advice and voted to breach the dam. What ensued was a stakeholder engagement process that spanned 30 months, as neighbors to the roadside reservoir fought hard for its preservation.

Following multiple public forums and deadline extensions, the Northampton BPW once again voted to remove the dam in October 2010. One month later, city councilors declined to support a “save the dam” resolution. The twin actions spelled disappointment for preservation advocates, but cleared the way for permitting to begin in earnest.

Affordable project financing was not initially available, as early efforts to obtain a FEMA grant fell through. Finally, in 2018, the city won a $634,000 climate resiliency grant from a designated Massachusetts dam and seawall fund. Massachusetts also awarded a $25,000 stream restoration grant, which gave a state-level ecologist a seat at the table. Water ratepayers funded the remainder of the $850,000 project.

Over time, authorization was gained from the U.S. Army Corps of Engineers, state environmental regulators, and local boards. Because the dam was eligible for inclusion in the National Register of Historic Places, tribal consultation and historical mitigation was required under Section 106 of the National Historic Preservation Act.

The Upper Roberts Meadow Reservoir Dam came down in stages in the summer of 2018. SumCo-Eco Contracting of Peabody, MA deployed two excavators — one with a long arm, and one with a short arm — and started to remove the large stone blocks. Over several rainy months, in a controlled process, around 10,000 cubic yards of sediment was sluiced downstream into the once-rocky streambed. By autumn, the reservoir had completely drained.

It has now been over a year since the dam came down. The Roberts Brook has formed a new channel within the former impoundment, and native riverine vegetation has started to grow. State fish and wildlife officials, as well as graduate students from the University of Massachusetts, will continue to monitor the site for trout habitat and water quality.

Perseverance and collaboration required
For 12 years, engineer Matthew Taylor led the Northampton project for GZA as their dams and levees group leader for their metro Boston offices. Asked about the role of patience in shepherding complex dam removal projects from start to finish, Taylor agreed that calm persistence is necessary on the consultancy side, but he quickly credited his municipal client for their own fortitude.

“The long duration of the project required patience and perseverance from GZA, but more so from the city,” he says. “In the end, we successfully removed a significant liability for the city and restored a beautiful new stream, and that has made it worth the effort.”

Northampton’s top city engineer struck a similar tone. David Veleta, P.E., noted that he inherited the project in 2016 from his predecessor, former city engineer James Laurila. Laurila. Working closely with former DPW director Edward “Ned” Huntley — who died in 2016 — Laurila first recommended GZA for the job in 2006. “Like all projects, large or small, a combination of patience, persistence and an openness to the changing dynamics that arise from all interested parties is essential for a successful project outcome,” Veleta remarks.

While the municipality has a strong engineering division, the “scope, range, and complexity” of the project required an outside consultant with specialized expertise, he noted. As city engineer, Veleta worked collaboratively with GZA. He and his staff reviewed and commented on project design, project approach,

contract documents, and permitting efforts while playing an active coordinating role during construction. “The dam removal project was unique for the city, and it was very rewarding to assist in seeing it through to completion after its extended period of development,” Veleta concluded.

In-stream sediment management cut costs and helped stream habitat
Looking back, the Upper Roberts Meadow dam removal project is noteworthy for several reasons. At the time, it was the tallest dam that had ever been removed in Massachusetts. But more significantly, the project showcased best practices in ecological restoration. The decision to sluice sediment downstream, rather than to dredge and dump, was central to that effort.

Early in the process, GZA determined that around 27,000 cubic feet of clean sediment had accumulated behind the dam. Because of the impoundment, lower reaches of the brook had become sediment-starved, creating conditions not ideal for spawning brook trout and benthic macro invertebrates. Ultimately, about 10,000 cubic feet of sediment were released downstream during the removal process, improving habitat for cold-water aquatic species.

The process, known as in-stream sediment management, replaced the city’s early intention to dredge the reservoir and deposit the sediment and woody debris in a detention basin. Constructing the basin would have required cutting five acres of forest and added some $500,000 in project costs. Instead, the decision to release the sediment in stages — an option carefully vetted by state environmental regulators — saved money and helped improve stream health.

In addition, risk analysis was conducted as part of the project design process. Care was taken to protect the integrity of a small downstream bridge and to make sure that roadway flooding would not occur as a result of sediment transport.  “We always look for infrastructure risk,” says Alex Hackman, a stream ecologist with the Massachusetts Division of Ecological Restoration, or MassDER. Hackman, who has participated in many dam removals, was a key member of the Northampton project team.

While there are short-term environmental impacts to sediment release, these are generally outweighed by the long-term benefits, Hackman emphasizes. “Biologically, it helps rebuild habitat downstream that has been degraded from the presence of a dam. We also know there is an impact of smothering downstream, but it will only last one or two years.”

Hackman says dam removal restores fish passage, mends fragmented habitat, improves water quality, and resets river processes. The view is supported by a growing body of scientific research on the ecosystem benefits of stream connectivity. When upstream sediment, wood, and nutrient loads are allowed to run free, a river or stream can start to heal. “It’s different in different places, so we’re all psyched to see what happens here,” he says. “It’s exciting to see that wall gone and to watch the river being reborn.”

Engineers work with ecologists
Collaboration between engineers and ecologists is an essential feature of today’s best dam removal projects, participants say. And there are signs that the next generation of practitioners will bring such a holistic mindset to their work as a matter of course.

Allison Roy is a Ph.D. stream ecologist with the U.S. Geological Service. At the University of Massachusetts Amherst, she co-teaches — in tandem with engineering faculty — a 10-student practicum on dam removal. Students within the cross-disciplinary practicum were keen observers of the Northampton project, even sitting in on management team conference calls.

“We’ve been training engineers and ecologists at UMass,” Roy states. “And we’re teaching them on both sides. There are differences in the language we speak, and mutual training is really important.” For instance, ecology students are learning how to read engineering plans, and engineering students are learning about habitat requirements.

Currently, her students are among those monitoring the upper Roberts Brook as it recovers from more than 135 years of impoundment. Data is being collected on water temperature, dissolved oxygen, and cold water aquatic species. Other such post-removal research is being conducted across the state, thanks to funding from MassDER.

Early on, critics of the Northampton dam removal effort argued that it would destroy an existing warm-water pond habitat. Asked about this assertion, Roy maintained that cold-water stream habitat is far more valuable. “The reality is that the warm water impoundment was created artificially, and we already have a lot of that kind of habitat across the state,” she says.

Even restoring a four-mile stretch of a cold-water fishery can support greater genetic diversity within a local

species population, allowing for greater resiliency in a changing world. “River ecology is complex,” she says. “It’s so much more than simply enabling fish passage.”

Hackman agreed.  “So you had a warm pond with low dissolved oxygen in the midst of a cold-water, highly-oxygenated trout stream. The dam did form some temporary habitat, but artificial habitat that had negative impact on the natural system that was there before.” And though the drained site still looks raw to the untrained eye, Hackman says that will change as nature takes its course. Vegetation will continue to grow, seasons will pass, and the newly reconnected trout stream is expected to become cooler and more productive. “Free flowing water makes a river ecosystem healthy.”

Public and private multidisciplinary team
By all accounts, a multi-disciplinary team, with experts from private and public sectors, helped deliver success in the Northampton dam removal case. And according to GZA’s Taylor, any engineering firm hoping to engage in such work must take care to build and sustain trusted professional relationships over time. “It takes a team approach for projects like this one to be successfully completed,” says Taylor.

A principal with GZA, Taylor joined the firm in 2007 and was immediately assigned to lead the Northampton project. He stayed the course through two mayoral administrations and held firm through leadership changes at the city’s Department of Public Works. He personifies a new breed of dam removal engineer, as he has extensive experience in many aspects of civil engineering with a primary focus on geotechnical engineering and dam and levee safety. He has a civil engineering degree from Northeastern and is a registered professional engineer in several northeastern states and an approved Independent Consultant for FERC Part 12D Dam Safety Inspections. He serves as the principal-In-charge for numerous dam and levee inspection, evaluation, rehabilitation, and construction projects.

Even under the best of circumstances, dam removal projects can take more than a decade to complete. Time must be allotted for community engagement, engineering studies, and navigating environmental requirements. Firms embarking on such projects should be prepared for a lengthy commitment.

While the Roberts Meadow project team shifted over time, its core members included included Taylor, Veleta, and MassDER’s Hackman. When SumCo EcoContracting arrived to do the actual work, construction team leader Robert Johnson joined the group. Northampton public works chief Donna LaScaleia, hired by the city in 2016, “carried the project over the finish line,” says Northampton Mayor David Narkewicz.

SumCo EcoContracting, with its ecological construction niche, is now approaching its 50th dam removal. Company principal Chad Sumner noted that the Northampton project was one of the first in the state to use in-stream sediment management. He said the sluicing practice is now becoming more common when there is a clean, uncontaminated sediment load behind a dam.

Small versus large dams
Small dam removal projects may seem tame compared to large, headline-grabbing demolitions, such as those planned or completed in the Pacific Northwest. For instance, four major hydroelectric dams are slated for removal on the Klamath River in California and Oregon, an effort that could open 400 miles of habitat for migrating salmon. And it’s been more than two decades since the Edwards Dam on the Kennebec River in Maine was breached, an iconic action that made international news and inspired a generation of environmentalists.

However, the bit-by-bit progress brought about by removing small dams in populated areas should not be underestimated. In the Northampton case, several obsolete downstream dams still remain on the Roberts Brook and Mill River. There is a good chance that such dams will eventually come down, providing ongoing opportunities to reconnect riverine ecosystems while also solving cost and liability problems for asset owners.

“That’s what New England is,” says Roy. “It’s thousands of small mill dams littering our entire landscape, and altering all of our rivers and streams. That means most progress will be incremental. You can’t just focus upon a single dam.”

While the ecological benefits of dam removal are real, such projects do change local landscapes and can result in the loss of historically significant structures. For instance, the Northampton dam was designed in part by Clemens Herschel, the notable 19^th century hydraulic engineer. For that reason and others, state and federal regulators required a historical mitigation plan.

According to documents, the large granite blocks that once comprised the Northampton dam were originally quarried in the nearby Berkshire Mountains. Asked about their fate, Veleta says select blocks were salvaged and placed along the walking path. Others were stockpiled for future use by the city.

To help preserve memories and historical awareness, SumCo Eco Contracting found and salvaged a millstone from a colonial-era bark mill and tannery at the site. The millstone is now on display alongside an unmarked walking trail that leads to a fenced-in viewing area at the top of the former dam abutment. The viewing area contains interpretive signage.

Asked if he had any advice for other engineering firms interested in dam removal, Taylor says it’s important for practicing engineers to keep current. Ecological research and new engineering protocols often develop in tandem, and the best practitioners will always keep learning.”

As for young engineers interested in the ecology-engineering nexus, Taylor says jobseekers should visit the GZA website. “We are always looking for hardworking, eager engineers and scientists who enjoy the outdoors and the environment and take pride in making a difference.”

Mary Serreze is a Massachusetts-based journalist with an interest in energy, the environment, and resilient infrastructure. As a former reporter for The Springfield Republican, she covered major energy siting controversies, state climate change policy, public works initiatives, municipal government, and more. She holds a master’s degree in regional planning from the University of Massachusetts and hails from a large extended family of scientists and engineers.