Heminway Pond Dam Removal
Background
Built on Steele Brook in Watertown in the early 19th century, Heminway Pond Dam was originally used for industrial purposes. The 670-foot-long earthen dam impounded about 5 acres in its 6-square-mile watershed, creating a pond that had a depth of about 4 feet. In 1955, the dam was destroyed by floods and then rebuilt into its modern form. Though it was converted to a water supply dam to serve the Watertown Fire District at some point, by 2009 the dam had no identified purpose. In a 2009 report authored by the Natural Resources Conservation Service, the dam, pond, and waterway experienced the following problems:
- Restricted fish passage
- Elevated water temperatures and bacteria due to geese population
- Iron precipitate deposition in the stream channel.
In hot weather and low-flow periods, the iron precipitate presented as orange-colored water, as seen in the photo above.
Removal
Discussions to remove Heminway Pond Dam began as early as 2002, with four goals in mind:
- improved water quality
- improved fish passage
- reduced owner liability
- further development of the Town's greenway project.
While the owners did consider other alternatives, such as construction of a fishway, removal of the "A" (low hazard class) dam was ultimately chosen as the best option. The cost for removal was initially estimated to be $700,000-$1,100,000, depending on the quantity of sediment to be re-used onsite.
In 2012, the Town of Watertown contracted Princeton Hydro to assist with the design and permits, which were required by DEEP and the U.S. Army Corps of Engineers. The Northwest Conservation District supported the project by providing education and conducting community outreach. With funding from the town and the EPA's Nonpoint Source Management Program, removal of the dam started and finished in 2018.
Click here for a time-lapse video of the removal (external site): time-lapse removal of Heminway Pond Dam
Outcomes
The removal of the dam in 2018 restored the natural aquatic habitat of this section of Steele Brook. By reconnecting 0.2 miles of waterway, the free-flowing river is now capable of allowing passage for fish and other aquatic species. The streambed and streambanks have stabilized, and upland wetlands have regrown - further restoring natural habitats.
Additionally, this restoration allowed the town to expand the Steele Brook Greenway, improving access to water, which provides passive and active recreation.