Faced with an Office of Dam Safety Order to repair the dam or take it down, the City asked GZA to identify the most cost-effective approach, provide design plans, obtain necessary permits, and act as the resident engineer during construction. The earthen dam with a stone masonry spillway is an approximately 35 feet tall and 125 feet. This High Hazard, former water supply dam had been in a Poor/Unsafe condition since the 1970’s.A dam breach would require tackling the issue of dealing with approximately 27,000 cubic yards of sediment impounded by the dam.




The City concurred with GZA’s recommendation for dam removal as the preferred alternative. Connecting high-quality trout habitat in the stream above and below the dam made the project a priority for MA Division of Ecological Restoration who eventually became a project partner. After years of meetings and deliberations with city residents and regulators, the City, with the help of GZA and MA DER, was able to obtain concurrence to permit the project as a staged dam removal with a controlled sediment release. The project approach was developed to “throttle” the release of about 10,000 to 11,000 CY of sediment to the downstream sediment starved reaches. A post-construction sediment survey completed in the early fall of 2018 revealed very good agreement with GZA’s design, specifically, the amount of sediment mobilized (about 10,800 CY) and the location of the newly formed stream within the former impoundment.




Practitioners from multiple GZA core service areas comprehensively and successfully addressed the City’s engineering, permitting, and construction support needs for the project. GZA also was successful in securing an EOEEA grant to cover 75% of the construction costs. The City’s liability was reduced by removing the Poor condition, High Hazard dam which also resulted in the removal of the tallest dam removal in Massachusetts. Project costs were reduced by using the innovative sediment release approach in lieu of dredging/offsite disposal, saving the City nearly $500,000. The newly formed stream re-established the connectively between two high-quality cold-water fishery habitats.

Related Insights
Related Insights


Record High Water Level In Central Wisconsin

In the August 2020 issue of the Badger Common’Tater , the official magazine of the Wisconsin Potato and Vegetable Growers Association, Jim Drought discusses the groundwater elevation database GZA...


Tracking Flocks of Red Knots, One Bird At A Time

In the Americas, vast flocks of the red knot travel from the Arctic all the way to Tierra Del Fuego during its seasonal migrations, with stops along the way down the coastlines of North and South...


Aging Dams and the Importance of Infrastructure

As a long-time corporate member of the Association of State Dam Safety Officials, GZA has been aware of the looming crisis with our nation’s dams for years. Every so often, a major and sometimes...