Montgomery Dam study explores repair options, fish passage

By Susan Mustapich | May 07, 2019
Photo by: Susan Mustapich A recent view of the emptied impoundment behind the Montgomery Dam, when the river is diverted through a stone sluiceway beside the Harbor Park seawall.

CAMDEN — A study of options for the Montgomery Dam, including repair of the existing dam, lowering the dam and demolishing the dam, has been published, but not yet discussed by the Select Board.

The study, conducted by Inter-Fluve, a national company with a Maine office in Damariscotta, has been underway since April 2018.

It concludes that full removal of the dam, combined with the restoration of the Megunticook River's natural channel, provides the greatest number of options for fish passage up the river. The study states that before the river was modified by people hundreds of years ago, it flowed down what is now a walking path in Harbor Park, which leads to a stone ramp and into Camden Harbor.

Another option for fish passage identified in the study is a fish ladder, which can be used along with the full repair of the existing dam, and a lowered dam.

Town Manager Audra Caler-Bell said May 7 that in past discussions Select Board members have been very positive about doing something different with the dam and about supporting some fish passage at the mouth of the Megunticook River. Caler-Bell said she has started talks with the owner of the Knox Mill property and the condominium association about the possible removal of the Montgomery Dam. There are two dams within the Knox Mill property.

The next step, according to Caler-Bell, will be a presentation of the dam study to the Select Board by Inter-Fluve. She expects the Select Board will decide which direction to take, and that stakeholders will be involved in the discussions.

Dam and fish passage options

The study looks at three dam management options, including full reconstruction of the dam spillway, lowering the spillway elevation by 4.5 feet, and full removal of the dam.

The spillway of the Montgomery Dam is located behind a number of Main Street businesses, including the Smiling Cow, Surroundings and the Camden Deli. It is perpendicular to the seawall that lines the perimeter of Harbor Park. The spillway creates an impoundment of water from the Megunticook River, which generally flows southeast over natural ledge, down to Camden Harbor.

For each option, the study examines the effect on flood control benefits upriver from the dam, the effect on fish passage options and the visual effects of each option. Initial costs and lifespan costs over a 50-year period are also considered.

Full spillway reconstruction results in the "least amount of change to the site as it exists today," according to the study. It would pose the most challenges to fish passage up the river, but fish passage would be possible through the use of a fish ladder. This option would retain the water in the impoundment between the dam spillway and the harbor side of numerous Main Street buildings. It would not provide any flood control benefits or ecological benefits to the Megunticook watershed.

Partial spillway reconstruction offers less-challenging fish passage solutions, still limited to fish ladders, and offers more potential or overall ecological recovery of the watershed, according to the study. The pool behind the dam would shrink to approximately 50 percent of its present size.

The full dam removal option would provide the greatest benefits to the town, in terms of reducing costs for operation and maintenance, and reducing upstream flooding impacts. This option would allow for "the most advantageous fish passage conditions and greatest benefits in terms of ecological recovery of the watershed," according to the study. Fish passage options with dam removal and restoration of the river channel in Harbor Park include a nature-like fishway and pool and weir fishways, in addition to the fish ladder option.

Dam removal would eliminate the pool behind the Main Street businesses, according to the study, which hypothesizes that "the aesthetic quality of the fish passage would likely offset changes associated with pool reduction."

The full study is 83 pages, and includes extensive information on the history of the dam site, fisheries information, river channel conditions, sediment, hydrolics and surrounding infrastructure, including buildings built over the river, and the Main Street bridge on Route 1.

Film advocating restoration of fish passage

On a parallel track to the long-awaited Montgomery Dam study, Select Board member Alison McKellar has made a short film showing that she found alewives trying to swim up into the mouth of the Megunticook River at Camden Harbor.

She previewed the film, made with filmmaker Josh Gerritsen at the April 23 Select Board meeting. The film follows her investigation into fish passage up the Megunticook River, and offers science-based advocacy for the restoration of fish passage and the river's natural environment. Dams were installed along the river to power diverse industries following the area's settlement in 1769. She said the river attracted the settlement, and before the area was named Camden, it was called Megunticook. McKellar discussed how dam inspections, insurance and maintenance are costly to the town.

The Montgomery Dam, overlooking Camden Harbor, was built to divert the river in order to turn the waterwheels of a grist mill, and later an anchor factory on the public landing. McKellar supports the view that the natural path of the river was along what is now a walkway in Harbor Park.

In the film, she narrates her quest to find expert accounts or historical documents proving that alewives, a saltwater species, migrated up the freshwater river to spawn.

She persisted though she could not find anyone who would say they knew of alewives swimming up the river. McKellar not only found a handwritten account of an 1806 town meeting where townspeople wanted dam owners to open sluiceways to allow the alewives and other fish to swim upriver to the lake, now called Megunticook, the film also shows her finding alewives trying to swim up into the mouth of the river at Camden Harbor in June 2018.

McKellar asked for the Select Board's support of a nongovernmental fundraising effort, possibly in partnership with a nonprofit environmental organization, for the dual projects of fish passage and watershed restoration. Board members were supportive, but agreed to discuss the issue at a future meeting.

Comments (1)
Posted by: Ronald Horvath | May 08, 2019 16:41

This discussion is going on world wide.  Technology has advanced to the point where dams are no longer necessary for producing power and the advantages of a natural fishery are far more valuable.    This is from the Guardian:

 

"Artifishal, a new documentary about salmon, might, in less capable hands, have been a tiresome screed, another damning diary of how humans have despoiled the Earth.

In salmon’s case, we have interrupted one of the most dramatic cycles of nature, the wild fish’s journey from the rivers where they spawn to the oceans where they grow and back again. The result is that fish have died, species that eat them have died, communities that depend on them have faded, the food supply has been polluted and a lot of tax dollars have been wasted.

 

Artifishal, directed by Josh “Bones” Murphy and produced by Yvon Chouinard of Patagonia, does tell that story. But that story is only the embers of something more, which the film steadily exhales over, oxygenates and causes to flame up."

 

"Over the decades, we have interrupted salmon by draining rivers, damming rivers, settling riverbanks, overfishing streams and injecting billions of genetically inferior fish into the wild population...  Breeding fish in tanks does not create the same fish as those bred in streams; launching fish over dams still interrupts the breeding cycle; and a lot of the fish inside those net pens, as the film gruesomely illustrates, are visibly sick to the point of making the viewer wonder how we can eat this stuff."
https://www.theguardian.com/film/2019/may/08/artifishal-film-fish-salmon-climate-change?CMP=fb_gu&utm_medium=Social&utm_source=Facebook&fbclid=IwAR3ZsagdJeMzViI_chePzgnwC5Zlx9dLrJt2cymO6Z7ZMnmpdpcnQgt90nM#Echobox=1557306755



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