A recently-released study of the Megunticook River from Camden Harbor to Lake Megunticook promotes a greener, heathier river and fish passage up to the lake as measures to reduce flooding in downtown Camden and improve the environment of the local watershed and regional waters.

This vision hinges on the removal of several downtown dams as well as other structures in the river, such as a waterwheel and weirs beneath the Brewster Building (a former shirt factory) and supports that hold up the Main Street bridge, which is on a schedule to be replaced in 2024 by the Maine Department of Transportation.

The Megunticook River Feasibility Report considers removal of the Montgomery, Knox Mill and Knowlton Street dams. This was first announced as the direction town government was exploring in summer 2019 by Town Manager Audra Caler.

However, the executive summary at the beginning of the study states that “model results showed that dam removal alone may not result in lowering the FEMA base flood elevations below the Camden Public Safety Building that is located directly adjacent to the Washington Street Bridge.”

Additional modeling shows structures beneath the former Brewster Building and the Washington Street bridge itself also directly influence flooding in this area, according to the study. While the Brewster building structures are looked at for removal, the bridge is not, as it was newly constructed in 2017.

Impacts of dam removal on flooding is only one of many topics that are expected to be discussed by the Select Board and public. The Select Board is planning to begin its discussions about the study in an upcoming workshop.

The assumptions for cost estimates for dam removal and fish passage on page 184 of the study are likely to attract much discussion. One example is the indication that certain fish passage options have either limited or greater potential for grant funding, based on the assumption that if dam removal is possible, grant funding for fish passage without dam removal is diminished.

A great deal of new information is available in the study, such as the measured amounts of sediment behind the downtown dams and the chemical analysis of that sediment. The largest deposit of sediment is behind the Knowlton Street dam, which drives the cost of removing the dam into the $3 million to $5 million range, according to the study.  The finding, based on analysis, is that chemicals in the sediment behind all the dams are similar to what is found in the sediment in Camden Harbor, according to the study.

Photographs of the river running through the Knox Mill buildings reveal the massive amount of built structures in the river, and birds-eye-view mapping of the Knowlton Street dam show how constrained the river is in that section.

Illustrations show what the river could look like in the future in the areas around the dams in 10 and 100 year flood events.

Other illustrations show the layout of possible fish passageways at the Knox, Knowlton, Seabright, East and West Dams.

The study also casts a new light on familiar land and riverscapes. One example is the description of the river between Mount Battie Street and Molyneaux Road as a stillwater pond created by the Seabright Dam.

Open water is only 8% of the watershed, with woody wetlands 4%, according to the study.

Of the landcover in the Megunticook River watershed, more than half is forested, with deciduous forest, 44%, evergreen 8% and mixed forest 17%. Developed space is only 9% of the watershed, with developed open space 6%, low intensity development 2%, medium intensity 1%.

Action plans with options for removing dam structures beneath the Brewster Building, and at the Knox Mill, Knowlton Street are part of the study. The feasibility of removing the downtown dams and the sediment behind the dams is studied is explored in great detail.

Action plans and options for fish passage are explored in detail for Seabright, East and West Dams.

Completing the study involved field work in the river by Interfluve and Gartley & Dorsky from July through November, 2020, reviewing a massive amount of available written information about the river, including historical documents about the river, dams, river flow and weather, geological and hydraulic information and and past and present engineering assessments of the dams.

The study posits that it is responding to a long-term initiative, with goals and objectives established by the town.

It describes the “overarching goals” of the town initiative as identifying and implementing river management options for the Megunticook River that improve flood and community resilience, restore habitat connectivity and ecosystem health, reduce infrastructure management needs, and enhance¬† landscape aesthetics and public access, and more.

The Megunticook River Feasibility Report can be found on the town of Camden website, camdenmaine.gov.