Explore the Megunticook River Watershed

• Owner: Town of Camden
• The Seabright Impoundment is not being evaluated for removal.
• Constructed: In 1888 by the Megunticook Woolen Company.

The Seabright Impoundment is a high hazard stone masonry and concrete overlay dam owned and operated by the Town of Camden and is located approximately 0.35 miles upstream of the Powder Mill Dam ruins. A high hazard potential dam is any dam whose failure or mis-operation will cause loss of human life and significant property destruction. It does not represent the current condition of the dam.

The Seabright Impoundment is NOT being evaluated for removal. It creates elevated water levels stretching from the dam all the way to Molyneaux Road (Seabright Impoundment). Options for fish passage around the impoundment are the only alternatives being considered. 

The Seabright Impoundment has been the site of a series of woolen mills over time, including the Seabright Woven Felt Company, which was incorporated in the early 20th century by William Paige and had the first automatic looms in Camden. Joe Sawyer developed a hydroelectric plant at the dam in the 1980s which was transferred to the Town in 2007. The plant was decommissioned in 2017.

• Owner: Private
• The Powder Mill dam ruins are being considered for removal but further evaluation is required.
• Powder Mills dam, which is now ruins, was built by E.H. Barrett and John Swann for a paper mill in 1828

Ruins are all that remain of this masonry dam structure located approximately 1.1 miles upstream of the Knowlton Street Dam in a more suburban setting. The structure is composed of stacked masonry blocks founded on bedrock.

The Powder Mill dam ruins are partially breached and are currently being evaluated to understand the impacts of removal on the watershed and river. The 2021 Feasibility Study recommended dam removal as the best option due to expected fish passage improvements and elimination of a local restriction to flood flows.

In the 1820s, a paper mill was constructed at the present‐day Powder Mill Dam ruins. The paper mill burned down in 1841 but was reconstructed as a powder mill, providing blasting powder for local quarrying operations. This powder mill includes two dams, the stone dam that is partially breached today and a smaller dam 330 feet downstream. The powder mill was eventually closed and then converted to a range of operations over the following decades. This included a woolen mill, poultry factory, and tent manufacturer.

• Owner: Private
• The Knowlton Street Dam is considered for removal.
• Built in 1854 by David Knowlton for a vessel-parts supply mill.

Further study will focus on developing a better understanding of the impact of the Knowlton Street dam on downtown flood risk as well as the impact to the upstream wetland behind the Camden-Rockport Middle School and the Camden Wastewater Plant.

The Knowlton Street impoundment contains the greatest volume of sediment. Sediment samples collected during the feasibility study were reviewed against probable effects thresholds for marine aquatic life. While there are some exceedances, they are not excessive or dissimilar to those seen on many other rivers in northern New England. Active management of impounded sediments will likely be required with any restoration option.

The 2021 Feasibility Study recommended dam removal as providing the greatest benefits to fish passage, flood risk, ecological conditions, and resiliency including significantly reduced operation, maintenance, and repair requirements.

In the mid‐19th century, David Knowlton established a factory at the Knowlton Street Dam that manufactured various essentials for sailing vessels. The factory burned down and was rebuilt several times. At present, the existing building is an assisted living facility.

While repairs were being made to the dam in the spring of 1990, a release of impounded sediment occurred, some of which was delivered to Camden Harbor. This incident prompted an investigation into the quantity and quality of sediment trapped in the impoundment. The evaluations completed in the 1990s formed the backdrop for the sediment evaluation at this site completed for the 2021 Feasibility Study. 

• Owner: Private
• The Knox Mill Dam is being evaluated to better understand its impact on downtown flood risk as well as options for fish passage or removal.
• Constructed: Knox Mill dam was built in 1870 for a saw and grist mill owned by James Richards. Just prior, in 1855, a dam was built below the location of the Knox Mill Dam, where Washington Street crosses the river between Gould Street and Ames Terrace; however, this dam no longer exists.

The Knox Mill Dam is a privately owned dam that is being evaluated to better understand its impact on downtown flood risk as well as options for fish passage or removal. The dam is a stone masonry and concrete overlay dam located near the center of Camden, approximately 980 feet upstream of the Montgomery Dam.

The 2021 Feasibility Study recommended dam removal as providing the greatest benefits to fish passage, flood risk, ecological conditions, and resiliency including significantly reduced operation, maintenance, and repair requirements. Management of impounded sediments will likely be required under any restoration scenario, but will be less costly than the Knowlton Street Dam.

The founder of Camden, James Richards, was the first owner of this dam. The Knox Woolen Mill subsequently produced felt belts for the paper industry at this location from the mid 19th century to the late 20th century. Since the closure of the Knox Mill Dam, the associated buildings have been converted to a range of commercial and residential uses.