The Montague Dam has been removed (with pictures)

The Ompompanoosuc River was an “unfailing source of water” for manufacturing in Post Mills

The Montague Dam has been removed (with pictures)
Left: View of the dam in August 2020. Right: The site as it looks in late August 2022. Photographs courtesy of Ron Rhodes, Connecticut River Conservancy

The Montague Rod and Reel dam was “a vestige of a once-bustling industry and the largest manufacturer of fishing rods in the country until it closed in 1933…”(wrote Li Shen in June of 2021). The dam, which was constructed at a falls upstream of the Route 113 bridge in Post Mills, retained a head of water to power the Montague Factory (formerly the Chubb factory) that stood on the downstream side of the bridge.

Early in the history of Thetford, in the era of water power, a series of waterfalls in this location attracted industry, starting with the saw and grist mills built by Eldad Post circa 1790, at the site of the upper dam. For the next 150 years the history of Post Mills was one of industry.

According to Child’s Gazetteer of Orange County (1888) the Ompompanoosuc River was an “unfailing source of water” for manufacturing in Post Mills, The dam powered a complex of mills, including a grist mill, a sawmill, and a wool-carding mill. They continued to operate in some form or another till about 1914. These factories stood upstream of the Route 13 bridge. In addition, a separate dam was built below the bridge, that took its water from the upper dam. It powered a linseed oil factory and cabinet shop. This business later became the famous Montague Rod and Reel Factory.

After multiple changes in ownership, and a series of fires and disasters in the form of floods, the factories around the upper dam were not rebuilt, leaving Montague Rod and Reel as the sole surviving industry. The owners reinforced the upper dam with concrete  and replaced the lower dam beside the factory, also with concrete. However, rod and reel manufacturing became a victim of the Great Depression and the factory closed in 1933. From 1937, under the new ownership of Walter Malmquist, it produced wood bobbins, and later other wood products. Malmquist also retained the water rights between his factory and Lake Fairlee, which allowed him to draw down the lake level to a certain height, via the Lake Fairlee dam, as production needed. Low lake levels in 1941 and a lawsuit in 1944 forced the mill to switch to fossil fuel. It closed for good in 1999. In 2010 the massive mill building was demolished and its adjacent concrete dam was removed.

Fast forward to 2022 and the upper dam, which remained as a semi-ruin, has finally been removed as well, allowing thel the Ompompanoosuc River to return to its natural state.

The project took 3 years to plan and execute from start to finish, under the leadership and guidance of Ron Rhodes of the Connecticut River Conservancy. The first year was spent working with the landowner, the second year in applying for grant funding from the US Fish and Wildlife Service and the NH Charitable Foundation, and it took a third year for engineers to design and plan the project.  However the dam itself was removed in a matter of days.

For the purposes of the mills, the river had been diverted into two channels, one – the river’s natural course – was managed by a gate that controlled the water level while the other was used to power the mills. The project began by blocking off the second, man-made channel with rocks, trees, and soil from onsite.

Then began the task of systematically removing the stones and concrete that comprised the dam. The concrete was relatively easy to break up and remove since it was poured before the era of steel-reinforced (rebar) concrete.

A majority of the stones were used to backfill the second channel, preventing the river from retaking this unnatural course during future highwater events.

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Ultimately, the grade of that bank was raised with rock to reinforce the foundation of the former grist and sawmill building and protect it from highwater events. These foundations were was left untouched by the dam removal project. A historic marker commemorating the mill site will be installed near Baker’s Store.

Sediment collected upsteam of the dam. On the far bank, the second channel is blocked by debris.`

Removing the dam and backfilling the second channel was only a portion of the project. The river channel also had to be restored to its natural course, including shifting large volumes of sediment that had collected behind the dam over the years.

Ron Rhodes from the Connecticut River Conservancy explains the dam removal process to Li Shen.

The excavation work had to be performed carefully to prevent too much sediment from flooding downstream.

With the dam removed and the second channel backfilled with stone, it was time to move the sediment that had accumulated upstream of the dam to the newly constructed riverbank.

Sediment was loaded into a small dump truck and then driven across the river and dumped to form the new riverbank.

Engineers stopped by throughout the project to check on progress.

With the new river channel in place, it became time to seed the disturbed areas using natural grasses and wildflowers.

Finally, a protective layer of hay was placed over the freshly seeded areas.

At last, the dam has been removed and the river has been restored.

“The trout, crayfish and other critters already are moving through the site,” Ron wrote over email. Sand from upstream, trapped for decades, is also making its way downstream already, helping to restore the natural riverbed and habitat of the Ompompanoosuc. .

There are estimated to be as many as 1,000 such dams in the Connecticut River basin. Ron has overseen the removal of 18 since 2014, including 3 this year.

Photo credit: Nick Clark

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