Yes, the dams do hold back water and form water impoundments. The Elm Street Dam slows water flows, raises water levels, increases water temperatures, and lowers dissolved oxygen levels (RRA, 2022) on a six-mile stretch of the river. However, both dams are in a state of disrepair with repairs suggested by various consultants and FERC (Federal Regulatory Commission).

Years ago the Bridge Street dam diverted water to Sparhawk Mill to generate hydropower, but as of 2014 power production ceased, the owner removed the power generating equipment and surrendered its operating license to FERC.

The last known use of the Elm Street dam, as noted in a 1959 Inland Fish and Wildlife fish habitat assessment report, was to flush chicken processing waste to the harbor from a plant located across the street from the history center.

The Bridge Street Dam removal project costs $1,501,000, which includes removal of the dam, fishway, and penstock, as well as rebuilding the wall of the abutting property.

American Rivers, the Royal River Alliance, Royal River Conservation Trust, and Maine Rivers are working together to raise funds for the restoration of the Royal River through fundraising, grant-seeking, and volunteer efforts. As stated in the Town Council resolution, the project will not be funded by Yarmouth taxpayers.

The Bridge Street Dam removal project began on July 22, 2026, and is currently underway. This phase of the restoration is fully funded.

We are currently fundraising for the removal of the East Elm Street Dam, which is planned for summer 2027.

The current opinion of probable cost for removing the dam is $999,100. An additional $280,000 associated with the project will include support for the Yarmouth History Center boat ramp extension, ADA accessibility and a dry-hydrant extension at Baston Park in North Yarmouth, and adaptive management at Middle Falls.

A fishway is a structure built to facilitate fish movement over or around dams and other barriers. Fishways incorporate a series of pools that fish ascend by swimming against a current, with places to stop and rest along the way. The flow of water into a fishway is managed to provide optimal flows during periods of migration, and the flow out of a fishway is en­gineered to attract fish to the entrance. The ability of different fish to utilize a fishway varies, so modern fishways are carefully designed and managed to pass targeted species.

No. The two Yarmouth fishways are currently inoperable, in disrepair, and have many functional deficiencies. A 2018 study concluded the fishways are a constraint on the long-term restoration of up & downstream passage for targeted fish (alewife, American eel, American shad, blueback herring, sea run brook trout, rainbow smelt, sea lamprey, striped bass) (Inter-Fluve, 2018).  The Maine DMR (Department of Marine Resources) has notified the Town of Yarmouth that fishway repair and maintenance would be a wasted effort due to their dated technology and limitations (Maine DMR, 2019). The fishways were constructed nearly 50-years ago and designed based on knowledge that is obsolete. Since then, fishway technology has greatly improved. For many design and construction reasons, if the existing fishways were repaired, their capability to pass fish would still be severely limited (Inter-Fluve, 2018). 

The fishways on the Yarmouth dams were not designed for all target fish types—for example, shad require a low flow rate and wider ramps since they migrate as a school. Although shad are good swimmers, they have lesser abilities than salmonoids (Passage of American Shad, 2012, Design of Fishways for Shad, 2002).

Bridge Street Dam Fishway (Inter-Fluve, 2018) - needs repairs and ongoing maintenance:

–Does not meet design standards for shad.

–Lacks juvenile eel passage (for spring up-stream migration).

–Lacks intentional downstream fish passage.

–Inadequately sized for expected run populations and resting pool areas.

–Provides insufficient attraction flow at fishway entrance.

East Elm Street Dam Fishway (Inter-Fluve, 2018) - needs repairs and ongoing maintenance:

–Replacement of weirs, gates, trash racks & control structures is needed.

–Entrance is blocked with boulders & adjacent channel requires modification.

–Entrance configuration is very poor with water flowing across the entrance.

–Stop log weir is in disrepair and blocked with debris, negating its use in managing flow.

–Outflow from the foundry by-pass channel forms a competing attractant flow.

–Does not meet the design standards for shad.

–Lacks juvenile eel passage (for spring up-stream migration).

–Lacks intentional downstream fish passage.

–Inadequately sized for anticipated run populations and for resting pool areas.

–Provides insufficient attraction flow at fishway entrance.

The Town of Yarmouth, working with the Maine Department of Marine Resources, constructed the Bridge St. fishway in 1974 and the East Elm St. fishway in 1979. The Town owns both dams. The fishways were retro-fitted onto the dams to allow native migratory fish such as alewife, blueback herring & shad to access critical spawning and rearing habitat as part of efforts to restore these fisheries in State waters and the Gulf of Maine. The fishways were also intended to benefit sea-run trout.

It is in the 1834 State legislative record that sea-run fish migrated up the Royal River. In 1834 a bill was introduced regulating the taking and management of sea run fish by North Yarmouth (Yarmouth split from North Yarmouth in 1849) residents and requiring fish passage at dams.  The bill was passed but functional fish passage was not enforced.

Due to design limitations, fishway improvement is not a viable option for restoring fish migration to and from Casco Bay and the Royal River watershed.  The fishways need to be replaced or the dams removed.  In a report from Inter-Fluve (2018) (a fish passage consulting firm) they developed preliminary cost estimates for functional fish passage at both dams.  Depending upon the style of fish passage, the 30-year life cycle cost, including construction and maintenance, ranged from $1.1 to $1.4-million per dam.  Based on recent fishway construction in Maine on a similar sized river, Trout Unlimited reported an estimated cost for construction alone would be approximately $1-million per each dam (Trout Unlimited, 2020b).  Annual fishway maintenance costs of $16,000–$20,000 per year would continue indefinitely for as long as the dams exist, this is in addition to the expense of maintaining the dams themselves. 

Yes. When dams and barriers are removed, sea-run fish return—click here for success stories! The Royal River is a relatively small river and would not sustain huge runs. Sea run fish are naturally imprinted to return to where they were spawned, but some fish species wander more than others.  Over time, on their own, sea run fish, some species much sooner than others, will return to the Royal River. If humans place spawn or mature fish ready to spawn in the watershed, sea run fish will return within a handful of years.

Improving the river habitat and access to it will likely benefit species including American shad, alewives, blueback herring, sea-run trout and American eel. Restoring fish passage can benefit mammals and avian predators, such as egrets, river otters, eagles, ospreys, cormorants and loons. 

“Restoring the Royal River will likely support the federally listed threatened Atlantic Sturgeon and endangered Shortnose Sturgeon overwintering habitat for adults; and reproductive and nursery habitat for egg and juvenile life stages.” –US Army Corps of Engineers, 2020a. 

The presence of sea-run fish—like alewife, shade and river herring—in the river is  required for the freshwater mussel life cycle as the earliest stage of mussel development (larvae) must attach themselves to host fish and then at a later stage release themselves and live in the riverbed. In the absence of alewife and other migratory fish, it's not surprising that many freshwater mussel species are at risk of extinction. Mussels filter silt, nutrients, bacteria, algae, toxins and other small particles from water, thus, keeping the water cleaner for other organisms and for recreation (Maine Department of Inland Fisheries and Wildlife).  Should freshwater mussels return robustly to the Royal River watershed they have the capability to significantly reduce the silt/clay size sediment in the water column that is transported downstream . 

In 2012, a small barrier in the side-channel bypass at the Royal River Middle Falls was removed (Bouchard, K, Portland Press Herald, 2012). In 2017, the U.S. Fish and Wildlife Service (USFWS) notified the Royal River Alliance that two new locations in the side-channel may hinder fish movement. The USFWS concluded a few days work in the side-channel would significantly improve fish passage at a relatively low cost (USFWS, 2017).

Based on figures supplied by the U. S. Fish and Wildlife Service for the amount of river herring and shad habitat available in the watershed and accepted numbers of returning adult fish that amount of habitat would support, the Royal River Watershed could see approximately 62,000 river herring (alewives and blueback herring) and 29,000 American shad (Trout Unlimited, 2020a). This tracks reasonably well for river herring with what occurred when alewives were being stocked into the upper watershed: measured at 46,485 in 1984, estimated at 50,000 in 1981. 

When dams and barriers are removed, sea-run fish return, which in turn benefits the bird community. "Once the dams are removed, and the fish are moving more freely, birds like ospreys and eagles in particular, herons, all those other fish-eating birds move with the fish. They certainly take advantage of that more open system and benefit from it. There is more biomass through the whole length of the river, when the dams are taken out." —quote from Judy Camuso, Commissioner of Maine's Department of Inland Fisheries and Wildlife, 2021.

Other animals like river otters depend on freshwater fish and also benefit from free running rivers.

The US Army Corps of Engineers (USACE) have been studying the Royal River under section 206 Aquatic Ecosystem Restoration since 2020.  They released a final report (USACE, January 2024)  stating the "Riverbed is primarily scoured bedrock & coarse substrate with a fringe of fine sediment along portions of the bank and the majority of the sediments within the channel profile appear to be highly mobile." In addition, the minutes of a February 13, 2024 meeting with the USACE , they reported "The findings of the [sediment probing] effort [in December 2024] were consistent with the Oct 2023 sampling effort in that the river bottom has little to no soft sediment and consists of bedrock/cobble. When soft sediment were present, they were mostly found along riverbanks."  

Stantec (with Field Geology Services) reported the same amount of sediment would be transported down the river and into the harbor, river channel, and Casco Bay with or without dams (Stantec, 2010; Field Geology Services, 2013). This is supported  by the lack of large areas of sediment deposition in the river channel.  However, more than 90% of the sediment is flushed to the bay and does not settle in the channel or harbor due to its small grain size, based on studies conducted by Stantec, 2013 and Woods Hole Group, 2010.

The volume of sediment behind the Bridge Street dam is 4,200 cubic yards (plus an 800 CY contingency, Stantec, 2015)—only 3.5% of the amount removed during the last harbor and channel dredge (143,000 CY). The volume of sediment in the Elm Street dam impoundment is larger (the exact amount is unknown), and likely equivalent to no more than a few years of accumulation. Roughly 143,000 cubic yards of material was removed during the 2015 harbor and channel dredge, which accumulated over 18 years (Portland Press Herald, 2015). 

Following East Elm Street dam removal, migration of sediment and short term bank erosion will likely occur within the river as it rebuilds its natural channel. However, long-term bank erosion in the impoundment is not expected to occur. Therefore, sediment production within the river will not significantly increase. In addition, there are limited amounts of sediment in the river for the first 3 miles upstream of the East Elm Street dam. This section of the river has very large and deep holes (some 25 feet deep) that can trap sediment as the river reworks the channel over time. Taken together, dam removal is unlikely to significantly increase sediment transport and delivery to the harbor (Stantec, 2013 and Fields Geology Services, 2013). 

The U.S. Army Corps reported in a Feb 2024 during a community meeting: "The findings of the [sediment probing] effort [in Dec 2023] were consistent with the Oct 2023 sampling effort in that the river bottom has little to no soft sediment and consists of bedrock/cobble. When soft sediment were present, they were mostly found along riverbanks." 

Marine clay soils form a large part of the Royal River watershed, resulting in the familiar chocolate brown river water. We cannot alter this underlying geology. The Royal River harbor has been dredged periodically since the Civil War era and will continue to be dredged for as long as there is navigation in the harbor and river channel, with or without the dams.

In the absence of the dams, sea run fish are likely to return (as discussed above) to the Royal River. The presence of sea-run fish—like alewife, shade and river herring—in the river is  required for the freshwater mussel life cycle. (It's not surprising that many freshwater mussel species are at risk of extinction.)  Mussels filter silt, nutrients, bacteria, algae, toxins and other small particles from water, thus, keeping the water cleaner for other organisms and for recreation (Maine Department of Inland Fisheries and Wildlife).  Should freshwater mussels return robustly to the Royal River watershed they have the capability to significantly reduce the silt/clay size sediment in the water column that is transported downstream . 

Elm Street Dam Impoundment: Sediment in the Royal River above the Elm Street dam was tested for toxic chemical contamination. The results showed minimal potential for risk to aquatic life (USACE, Feb 2024 , USACE, Apr 2024 and Stantec, 2013).

Bridge Street Dam Impoundment: The sediment in the Bridge St. impoundment was tested for toxins and the results showed minimal potential for risk to aquatic life (USACE Feb 2024; USACE, Apr 2024). 

Stantec, an engineering firm, also tested the sediment in the Bridge St. impoundment for toxins and reported in 2016 that while one of ten sediment samples from the Bridge Street impoundment had PAH (polycyclic aromatic hydrocarbons) and mercury levels of concern, collectively the ten samples did not (Stantec, 2016). These compounds were found in sediment adjacent to the 325-acre Yarmouth Village storm drain outlet and a storm water run-off site from the Rte. 1 overpass. The contaminants are largely from incomplete combustion of petroleum & wood, engine oil spillage and fossil-fuel-derived materials (e.g. coal tar sealant). The presence of PAH at this location will remain whether the dams remain or are removed due to continued storm water run-off. The Maine DEP confirmed Stantec’s conclusion that the sediment from the Bridge St. dam impoundment is clean overall and has minimal potential risk to aquatic life (Stantec, 2016). This conclusion allows dredged materials to be safely disposed of—at a reasonable cost—at a site designated in Casco Bay.

From all available data and from past harbor dredging experience, the contamination concentrations of impoundment sediments will not alter where the harbor dredge material is currently disposed, either for beneficial reuse or at the Portland Disposal Site—an ocean designated location beyond Halfway Rock. 

One riverbed location—far below the Bridge St. dam—was thought to have more than 10 times the mercury than any other.  This site was retested by the US Army Corps of Engineers and they reported that there was no trace of mercury at that site downstream of the Bridge St. dam (USACE , Feb 2024). The mercury source was thought to be from ash from the former pulp and paper mill in Yarmouth.  Dam removal or dam retention would not have impacted sediment transport at that downstream location. 

In the absence of the dams, sea run fish are likely to return (as discussed above) to the Royal River. The presence of sea-run fish—like alewife, shade and river herring—in the river is  required for the freshwater mussel life cycle. (It's not surprising that many freshwater mussel species are at risk of extinction.)  Mussels filter silt, nutrients, bacteria, algae, toxins and other small particles from the water, thus, keeping the water cleaner for other organisms and for recreation (Maine Dept of Inland Fisheries and Wildlife).  Should freshwater mussels return robustly to the Royal River watershed, they have the capability to significantly reduce the silt/clay size sediment in the water column that is transported downstream . 

The middle of the harbor and the river channel out to Parker Point was designated a federal navigation channel in 1960. The US Army Corps of Engineers (USACE) dredges that portion of the harbor and channel. The navigation channel was last dredged by the USACE during the winter of 2014/2015. The prior USACE dredging was in 1997 (USACE, 2020b).   

Users of the harbor and channel would prefer more frequent dredging. The Yarmouth marina owners dredge their slip areas every 5 to 10 years, which are not part of the federal navigation channel.

The US Army Corps of Engineers (USACE) is responsible for monitoring the need for dredging the numerous federal navigation channels and for prioritizing and budgeting those needs in its annual funding requests to Congress.  Congress is responsible for appropriating funds to dredge the federal navigation channels.  There is political jockeying for priority in project funding as there is never enough annual funding to cover all needs.  This makes predicting the dredging timetable difficult.  Once the funds have been appropriated, however, the USACE is responsible for contracting and managing the dredging.

The Yarmouth marinas are responsible for dredging within their slips, and the Town of Yarmouth is responsible for dredging at the public boat ramp, because these areas lie outside the federally designated navigation channel.

No. Sonar bathymetry work done for the Town of Yarmouth in 2013 indicates that a reflecting pool will remain after the Bridge Street dam is removed, although  the pool will be shallower and narrower than the existing pool. This was confirmed during a voluntary Bridge Street dam drawdown in 2010.  Upstream of the Beth Conden walking bridge a now submerged water fall/tumble will be exposed with a new separate pool formed above that tumble extending to the base of Third Falls (Stantec, 2010).

The removal of the Elm Street dam would lower the water level of the six-mile impoundment behind the dam by approximately 5.6-feet (Stantec , 2010). Instead of flat water, the river would look and act more like a river. The canoe put-in at the Yarmouth History Center would need to be moved upstream because the water would be flowing toward a cascade. However, Elm Street dam removal will also result in significant beneficial impacts in the upstream impoundment like expanded fishing of stocked fish with the addition of sea-run fish species and new opportunities to observe diverse wildlife species that target migratory fish, such as eagles, osprey, heron, cormorants, river otters and kingfishers. The removal of the Bridge Street dam would likely improve fishing along the pathway up to the Elm Street dam (Maine Rivers, 2013). There’s very little recreation in the river now between the two dams.

Following dam removal, the water surface level immediately upstream of the East Elm St Dam is predicted to drop by 4.7-ft.  However, 370-ft upstream, the water level will drop by 4.0-4.5-ft due to the presence of a bedrock ridge that spans the river behind the History Center on East Elm Street. USACE, 2024. The rock ridge forms a natural dam similar to what is naturally present at Grist Mill Falls. 

RRA members are your neighbors. We are residents of Yarmouth and surrounding communities who care about the health of the Royal River. We are teachers, engineers, architects, retirees, volunteers, scientists and others.  We do not represent other conservation groups. They do a fine job representing themselves and we are happy to work alongside any organizations with common goals.