Sawyer Mill Dam Removal

Dover, New Hampshire

The Bellamy River runs beneath the historic renovated Sawyer’s Mill in Dover, New Hampshire. For hundreds of years, migrating fish in the river have met a barrier on their way upstream—one that they’ve faced since two dams were first constructed to power sawmills in the 1800s. Upon reaching the mill, the river flowed over the spillways of two stone masonry dams . Recognizing that these dams were a hazard to migrating alewife and herring, as well as a potential risk to surrounding buildings in the event of a major flood, the mill’s owner worked with the New Hampshire Department of Environmental Services (NHDES) to remove the dams .

The VHB team got to work on removal of the upper dam, following the earlier removal of the lower dam, and provided a complete redesign to address existing project challenges. Working under an accelerated schedule—112 days from project kickoff to issuing complete plans and specifications for bid—we coordinated with multiple agencies to secure the necessary permits and address fish passage concerns. The final design accommodated fish passage, met NHDES Dam Bureau flood safety standards, confirmed the stability of adjacent mill buildings, preserved historic features, and was completed on time and under budget. The truest sign of success? Bellamy River is flowing again, and the first successful alewife migration was confirmed in May 2020.

The now free-flowing Bellamy River runs between the remnants of the former upper dam. The Upper Sawyer Mill Dam blocks a river from flowing under a building built over a river. An excavator removes the granite masonry blocks of the dam that had blocked a river.


  • Sawyer’s Mill Associates


  • Civil Engineering

  • Construction Monitoring

  • Historic Evaluation

  • Permitting

  • Stream Restoration Design