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Each spotlight provides an inside look at our collaboration, teamwork, and accomplishments with a specific client. We value our client relationships and pride ourselves on forming strong ties with organizations that share our values of creating a better future for people and our planet. Meet the Musconetcong Watershed Association The Musconetcong Watershed Association (MWA) is an independent, non-profit organization dedicated to protecting and improving the quality of the Musconetcong River and its watershed, including its natural and cultural resources. Members of the organization are part of a network of individuals, families, and companies that care about the Musconetcong River and its watershed, and are dedicated to improving the watershed resources through public education and awareness programs, river water quality monitoring, promotion of sustainable land management practices, and community involvement. Princeton Hydro has been working with MWA in the areas of river restoration, dam removal, and engineering consulting since 2003. To develop this Client Spotlight, we collaborated with MWA's Executive Director Cindy Joerger and Communications Coordinator Karen Doerfer: Q: What makes MWA unique? A: As a watershed association, we focus on a specific place. This includes the Musconetcong River, a National Wild and Scenic River, as well as the area’s cultural, historical, recreational, and natural resources. We take a watershed focus, seeking to monitor the river and upstream areas to ensure it maintains good water quality. Q: What does MWA value? A: MWA values community. Our membership is mostly grassroots, including residents, riverfront landowners, farmers, and local businesses. We value the long-term community of people who have helped form the organization, improve the river, and protect the scenic and historic resources that make our watershed unique. Q: How long has MWA been working with Princeton Hydro? [caption id="attachment_5512" align="alignnone" width="596"] Dam removal project partners and community members pose with Sally Jewell at the Hughesville Dam removal event on Sept. 8, 2016. Photo Credit: USFWS.[/caption] A: Princeton Hydro has helped MWA with dam removal projects since the very first one, the Gruendyke Mill Dam, which was an obsolete dam on the border of Hackettstown and Mount Olive. Since then, Princeton Hydro has helped with four other dam removal projects and is currently assisting in the removal and restoration of the Beatty’s Mill Dam in Hackettstown, providing engineering plans and project management support. The dam removals in the lower Musconetcong River have created a free-flowing passage to the Delaware River, and the removal of the Hughesville Dam welcomed the return of American shad less than a year after its removal. Q: What types of services have Princeton Hydro provided to your organization? A: Princeton Hydro has provided MWA with dam removal services on the Musconetcong River, most notably, the removal of Hughesville Dam, which brought Secretary of the Interior, Sally Jewell, out for its notching. Princeton Hydro has also helped us with the engineering and design for the Musconetcong Island Park Project, which involves the demolition of a building in a Historic District and the replacement of new, safer stairs. We value Princeton Hydro’s expertise in environmental permitting, hydrology, and fisheries, as we have utilized this expertise to review development proposals and conduct fish surveys. Q: Do you have a favorite or most memorable project we’ve worked on together? A: The Hughesville Dam removal saw many successes and a few challenges we had to overcome as a team. After the initial removal and restoration, we worked together on another streambank restoration project to further stabilize the streambank near the dam removal site. This dam removal restored over 5 miles of free-flowing river to the Delaware River and will help lay the groundwork for the Warren Glen Dam removal, which is the largest dam on the Musconetcong River. https://www.facebook.com/watch/?v=969581229908361 Q: What are some exciting things your organization is working on right now? [caption id="attachment_5515" align="alignnone" width="1128"] Photo from Princeton Hydro led volunteer clean-up effort on the Musconetcong River in 2018. The team picked-up garbage along the road and riverbank, and pulled trash from the riverbed.[/caption] A: MWA is still working to restore the Asbury Mill, which we plan to use as an educational and eco-tourism hub for the community, as well as a much-needed office space for our growing staff. We’ve also received some exciting new grants that will help us continue to involve the community in efforts to protect and improve water quality. Our “Push Back the Lawn” campaign will allow us to reach out to small landowners and educate them on the importance of riparian buffers. This year has also brought some challenges for our organization, but we are excited to be picking up our River Cleanup again this fall. Normally, we conduct a watershed-wide cleanup in April, but due to COVID-19, we had to push it back. However, families and small groups are glad to be able to get out and give back by picking up trash that has collected with increasing staycations and small trips. Q: What drives you to want to go to work every day? A: Working for such a small organization, it is easier and more gratifying to see the impact it's making. Our staff gets to see a lot of projects from start to finish, so it’s rewarding to be able to have your stamp on something you watched grow from its inception to conclusion. Q: How can Princeton Hydro support you/your organization in the future? A: In the upper watershed, we are hoping that Princeton Hydro, in concert with others, can continue to help guide improvements to the water quality of Lake Hopatcong. The lake acts as our headwaters and is the largest in New Jersey. Last year, it suffered a serious issue with Harmful Algal Blooms. We are also looking forward to the Beatty’s Mill Dam removal project, where we will remove a remnant dam and reduce streambank erosion. We hope this will roll into another similar project at Newburgh, which should improve water quality and fish habitat and decrease flooding severity in the Hackettstown area. … Click below to read the previous edition of our Client Spotlight blog series, which features the Lake Hopatcong Foundation: https://princetonhydro.com/client-spotlight-lake-hopatcong-foundation/ [post_title] => Client Spotlight: Musconetcong Watershed Association [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => musconetcong-watershed-association [to_ping] => [pinged] => [post_modified] => 2025-01-02 14:18:19 [post_modified_gmt] => 2025-01-02 14:18:19 [post_content_filtered] => [post_parent] => 0 [guid] => https://www.princetonhydro.com/blog/?p=5510 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 2 [filter] => raw ) [1] => WP_Post Object ( [ID] => 3213 [post_author] => 3 [post_date] => 2019-04-17 19:39:44 [post_date_gmt] => 2019-04-17 19:39:44 [post_content] => Wreck Pond is a tidal pond located on the coast of the Atlantic Ocean in southern Monmouth County, New Jersey. The 73-acre pond, which was originally connected to the sea by a small and shifting inlet, got its name in the 1800s due to the numerous shipwrecks that occurred at the mouth of the inlet. The Sea Girt Lighthouse was built to prevent such accidents. In the 1930s, the inlet was filled in and an outfall pipe was installed, thus creating Wreck Pond. The outfall pipe allowed limited tidal exchange between Wreck Pond and the Atlantic Ocean. In the 1960s, Wreck Pond flourished with wildlife and was a popular destination for recreational activities with tourists coming to the area mainly from New York City and western New Jersey. In the early spring, hundreds of river herring would migrate into Wreck Pond, travelling up its tributaries — Wreck Pond Brook, Hurleys Pond Brook and Hannabrand Brook — to spawn. During the summer, the pond was bustling with recreational activities like swimming, fishing, and sailing. Over time, however, the combination of restricted tidal flow and pollution, attributable to increased development of the watershed, led to a number of environmental issues within the watershed, including impaired water quality, reduced fish populations, and flooding. Throughout the Wreck Pond watershed, high stream velocities during flood conditions have caused the destabilization and erosion of stream banks, which has resulted in the loss of riparian vegetation and filling of wetlands. Discharge from Wreck Pond during heavy rains conveys nonpoint source pollutants that negatively impact nearby Spring Lake and Sea Girt beaches resulting in beach closings due to elevated bacteria counts. Watershed erosion and sediment transported with stormwater runoff has also contributed to excessive amounts of sedimentation and accumulations of settled sediment, not only within Wreck Pond, but at the outfall pipe as well. This sediment further impeded tidal flushing and the passage of anadromous fish into and out of Wreck Pond. In 2012, Hurricane Sandy caused wide-spread destruction throughout New Jersey and the entire eastern seaboard. The storm event also caused a major breach of the Wreck Pond watershed’s dune beach system and failure of the outfall pipe. The breach formed a natural inlet next to the outfall pipe, recreating the connection to the Atlantic Ocean that once existed. This was the first time the inlet had been open since the 1930s, and the reopening cast a new light on the benefits of additional flow between the pond and the ocean. Hurricane Sandy sparked a renewed interest in reducing flooding impacts throughout the watershed, including efforts to restore the water quality and ecology of Wreck Pond. The breach caused by Hurricane Sandy was not stable, and the inlet began to rapidly close due to the deposition of beach sand and the discharge of sediment from Wreck Pond and its watershed. Princeton Hydro and HDR generated the data used to support the goals of the feasibility study through a USACE-approved model of Wreck Pond that examined the dynamics of Wreck Pond along with the water bodies directly upland, the watershed, and the offshore waters in the immediate vicinity of the ocean outfall. The model was calibrated and verified using available “normalized” tide data. Neighboring Deal Lake, which is also tidally connected to the ocean by a similar outfall pipe, was used as the "reference" waterbody. The Wreck Pond System model evaluated the hydraulic characteristics of Wreck Pond with and without the modified outfall pipe, computed pollutant inputs from the surrounding watershed, and predicted Wreck Pond's water quality and ecological response. The calibrated model was also used to investigate the effects and longevity of dredging and other waterway feature modifications. As part of the study, Princeton Hydro and HDR completed hazardous, toxic, and radioactive waste (HTRW) and geotechnical investigations of Wreck Pond's sediment to assess potential flood damage reduction and ecological restoration efforts of the waterbody. The investigation included the progression of 10 sediment borings conducted within the main body of Wreck Pond, as well as primary tributaries to the pond. The borings, conducted under the supervision of our geotechnical staff, were progressed through the surgical accumulated sediment, not the underlying parent material. Samples were collected for analysis by Princeton Hydro’s AMRL-accredited (AASHTO Materials Reference Library) and USACE-certified laboratory. In accordance with NJDEP requirements, sediment samples were also forwarded to a subcontracted analytical laboratory for analysis of potential nonpoint source pollutants. In the geotechnical laboratory, the samples were subjected to geotechnical indexing tests, including grain size, organic content, moisture content, and plasticity/liquid limits. For soil strength parameters, the in-field Standard Penetration Test (SPT), as well as laboratory unconfined compression tests, were performed on a clay sample to provide parameters for slope stability modeling. The culvert construction and sediment dredging were completed at the end of 2016. Continued restoration efforts, informed and directed by the data developed through Princeton Hydro's feasibility study, are helping to reduce the risk of flooding to surrounding Wreck Pond communities, increase connectivity between the pond and ocean, and improve water quality. The overall result is a healthier, more diverse, and more resilient Wreck Pond ecosystem. During the time of the progression of study by the USACE, the American Littoral Society and the towns of Spring Lake and Sea Girt were also progressing their own restoration effort and completed the implementation of an additional culvert to the Atlantic Ocean. The American Littoral Society was able to utilize the data, analysis, and modeling results developed by the USACE to ensure the additional culvert would increase tidal flushing and look to future restoration projects within Wreck Pond. To learn more about our geotechnical engineering services, click here. … [post_title] => Study Data Leads to Healthier Wreck Pond Ecosystem [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => wreck-pond [to_ping] => [pinged] => [post_modified] => 2025-06-26 16:42:02 [post_modified_gmt] => 2025-06-26 16:42:02 [post_content_filtered] => [post_parent] => 0 [guid] => http://www.princetonhydro.com/blog/?p=3213 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [2] => WP_Post Object ( [ID] => 3240 [post_author] => 3 [post_date] => 2019-02-20 22:31:51 [post_date_gmt] => 2019-02-20 22:31:51 [post_content] => [caption id="attachment_2294" align="alignright" width="2560"] A view of the Columbia Dam at the beginning of the removal process.[/caption] On the Paulins Kill, the 100-year old Columbia Lake Dam has almost been completely removed, and fish passage has been restored! Since the first cut was executed on the main dam in August, many exciting advances have been made towards restoring the Paulins Kill back to its natural state. Check out the video below, courtesy of the New Jersey Nature Conservancy Volunteer Drone Team. [embed]https://youtu.be/-KaBBFy-qBM?si=EmSLlqJKz5T4W2ML[/embed] Piece by piece, the dam was notched out throughout the fall season and is now completely removed with the exception of the dam apron, the horizontal concrete structure that sits downstream of the dam, and the section of the dam that sits below the riverbed. The part of the dam in the riverbed is now being removed all the way down to three feet under the ground. The full removal is estimated to be complete by mid-March. In mid-August, the first cut was widened to 80 feet, allowing for better management of high flows during storm events, which had been posing a challenge immediately following the first cut. In late August, the installation of rock vanes at the Brugler Road Bridge began. Rock vanes are engineered, in-stream structures that help to stabilize a channel while enhancing aquatic habitat and movement. The rock vanes installed at the Brugler Road Bridge site are cross vanes. Cross vanes consist of a set of boulders angled upstream on a river, with another section of smaller rocks placed upstream. The taller sections of the cross vanes deflect the streamflow away from the banks, decreasing scouring effects. Instead, the flow travels over the rock walls and concentrates down the center of the channel, creating a deep and elongated pool in the middle of the stream. Velocities between the notches in the rock vanes were evaluated using a velocity meter in accordance with the design specifications originally proposed. Based on the U.S. Fish and Wildlife Service fish passage design criteria, velocities in the notches could not be greater than 8.25 feet per second. All of the velocity measurements in this rock vane were below the maximum thresholds, ensuring no blockage of fish passage is made through the vanes. Since the removal of the dam began, vegetative growth from the natural seedbed of the upper impoundment has been observed (see photo below). In October, scour protection installation commenced at the Warrington Road Bridge site. After the team conducted geotechnical test pits, they discovered that a concrete scour wall that slopes out to the Paulins Kill was present and deep enough to be able to install rock at the necessary depth. They also found that the existing gabions, caged baskets filled with rock or concrete often used to protect against erosion, were intact and could be left in place. The team installed four (4) feet of riprap under and around the bridge in the riverbed and tied it into the existing grade of the banks. The original notch in the dam was lowered one foot per day starting in mid-December, reducing water surface elevations down to the apron elevation during the month of January. To accommodate NJ Fish and Wildlife’s request for animal passage under the I-80 bridges, an area of the previously installed riprap on the northwest abutment wall was flattened out and filled in with river cobble. This path will promote wildlife movement under the bridge as opposed to through the existing tunnel. Currently, rock vanes are being installed under the I-80 bridges specifically to enhance fish passage. These structures vary slightly from the rock vanes at the Brugler Road Bridge site, as they are designed to slow river flow, helping migrating fish travel upstream and traverse a 5-foot elevation difference in the streambed, much like a fish ladder. These rock vanes are more than halfway completed and are on track to be finished in time for fish populations to make full use of them. The next steps are to finish the demolition of the dam and the construction of the fish passage rock vanes under the I-80 bridges, plant vegetation throughout the upper impoundment, create a recreational trail through the upper impoundment, and plan for fishing and boating access! Stay tuned for more exciting developments on this incredible project. Thank you to our project partners: The Nature Conservancy, American Rivers, U.S. Fish and Wildlife Service, and NJDEP Division of Fish and Wildlife Service. ... Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of a dozens of small and large dams in the Northeast. To learn more about our fish passage and dam removal engineering services, visit: bit.ly/DamBarrier. [post_title] => Fish Passage Restored on the Paulins Kill [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => fish-passage-restored-on-the-paulins-kill [to_ping] => [pinged] => [post_modified] => 2025-11-04 02:27:07 [post_modified_gmt] => 2025-11-04 02:27:07 [post_content_filtered] => [post_parent] => 0 [guid] => http://www.princetonhydro.com/blog/?p=3240 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [3] => WP_Post Object ( [ID] => 2594 [post_author] => 3 [post_date] => 2018-09-18 15:53:10 [post_date_gmt] => 2018-09-18 15:53:10 [post_content] => As dams age and decay, they can become public safety hazards, presenting a failure risk and flooding danger. According to American Rivers, “more than 90,000 dams in the country are no longer serving the purpose that they were built to provide decades or centuries ago.” Dam removal has increasingly become the best option for property owners who can no longer afford the rising cost of maintenance and repair work required to maintain these complex structures. Dams can also cause environmental issues such as blocking the movement of fish and other aquatic species, inundating river habitat, impairing water quality, and altering the flow necessary to sustain river life. Removing nonfunctional, outdated dams can bring a river back to its natural state and significantly increase biodiversity for the surrounding watershed. [caption id="attachment_2620" align="alignleft" width="268"] A view from the site of the Heminway Pond Dam removal on July 19, 2018.[/caption] Currently, work is underway in Watertown, Connecticut to remove the Heminway Pond Dam, which restricts fish passage in Steele Brook, creates a pond with increased water temperatures and high bacterial levels due to high geese populations, and encourages deposition of iron precipitate in the stream channel just downstream of the dam. Princeton Hydro designed the engineering plans, managed permitting and is now overseeing construction for the removal project. The removal of the Heminway Pond Dam is identified as an integral component in addressing water quality impairment between the dam and Echo Lake Road. CT DEEP recently published this piece encapsulating the Heminway Pond Dam removal project: REMOVAL OF HEMINWAY POND DAM ON STEELE BROOK IN WATERTOWN UNDERWAY After almost 15 years of discussion and planning with the Town of Watertown and other partners, removal of Heminway Pond Dam on Steele Brook in Watertown finally got underway in early July. Though no longer functional, the dam and pond were originally constructed to supply water for a former thread/string mill. The Town acquired the dam and pond from the Siemon Company, the most recent owner, in 2007 with an eye towards removing the dam, restoring the river and converting the dewatered impoundment area into a passive recreation area, including an extension of the Steele Brook Greenway. With these goals in mind, the Town approached CT DEEP for help with removal of the dam. As it turns out, CT DEEP, has also had a strong interest in seeing this dam removed. It is anticipated that dam removal will improve the hydrology in this section of Steele Brook and eliminate a water quality impairment which manifests itself during hot weather and low flow conditions, as an orange-colored plume of water (due to iron precipitate) immediately downstream of the dam that impacts aquatic life. Dam removal would also benefit fisheries by restoring stream connectivity and habitat. Working towards these mutual goals, CT DEEP was able to provide federal CWA 319 nonpoint source grant funding to USDA NRCS to develop a watershed-based plan for Steele Brook to address nonpoint source impairments that includes a dam removal feasibility analysis for Heminway Pond Dam. Based on the recommendations in this plan, CT DEEP subsequently provided additional 319 grant funds to the Town of Watertown to hire a consultant to develop a dam removal design package, and assist with permitting and preparation. With the Town of Watertown as a strong and vested partner, CT DEEP is now helping this project over the finish line by providing a combination of 319 and SEP funds to accomplish the actual dam removal and restoration of Steele Brook. Dayton Construction Company is performing the construction and Princeton Hydro is the consultant overseeing the project on behalf of the Town. The Northwest Conservation District is also assisting with the project. It is anticipated that the majority of the work will be completed by this Fall. U.S. EPA, ACOE and CT DEEP have all played active roles with regard to permitting the project. Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of dozens of small and large dams in the Northeast. Click here to read about a recent dam removal project the firm completed on the Moosup River. Updated 2023: The U.S. Environmental Protection Agency featured the Heminway Pond Dam Removal and Steele Brook Restoration project as a “Nonpoint Source Success Story.” Click here to read it now. And click below to watch the time lapse video footage of the removal and restoration of Heminway Pond Dam and Steele Brooke. [embed]https://www.youtube.com/watch?v=O-X4W2YS3l0[/embed] … [post_title] => Dam Removal Underway in Watertown, Connecticut [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => heminway-dam-removal [to_ping] => [pinged] => [post_modified] => 2023-11-08 17:15:36 [post_modified_gmt] => 2023-11-08 17:15:36 [post_content_filtered] => [post_parent] => 0 [guid] => http://www.princetonhydro.com/blog/?p=2594 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [4] => WP_Post Object ( [ID] => 2334 [post_author] => 3 [post_date] => 2018-08-15 12:07:45 [post_date_gmt] => 2018-08-15 12:07:45 [post_content] => Freshwater mussels are among the oldest living and second most diverse organisms on Earth with over 1,000 recognized species. Here in the eastern part of the U.S., we have more species of freshwater mussels than anywhere in the world. Unfortunately, freshwater mussels are one of the most rapidly declining animal groups in North America. Out of the 300 species and subspecies found on the continent, 70 (23%) have been federally listed as "Threatened" or "Endangered" under the Endangered Species Act. And, in the last century, over 30 species have become permanently extinct. So, why are populations declining so fast? Freshwater mussels are filter feeders and process large volumes of the water they live in to obtain food. This means of survival also makes them highly susceptible to industrial and agricultural water pollution. Because they are constantly filtering water, the contaminants and pathogens that are present are absorbed into the mussel’s tissues. As such, mussels are good indicators of water quality and can greatly contribute to improving water quality by filtering algae, bacteria and organic matter from the water column. Not only do freshwater mussels rely on water quality, they are dependent on fish and other aquatic organisms for reproductive success. In order for a freshwater mussel to complete the reproduction process, it must “infect” a host fish with its larvae. The method depends on the specie of mussel. Some species lure fish using highly modified and evolved appendages that mimic prey. When a fish goes into investigate the lures, the female mussel releases fertilized eggs that attach to the fish, becoming temporarily parasitic. Once the host fish is infected, it can transfer the mussel larvae upstream and into new areas of the river. Both habitat loss from dam construction and the introduction of pesticides into the water supply has contributed to the decline of freshwater mussels. With approximately 300 mussel species in the U.S. alone, a critical component of restoring and revitalizing mussel populations is truly understanding their biology, which begins with the ability to properly differentiate each species and properly identify and catalog them. Princeton Hydro’s Senior Scientist Evan Kwityn, CLP and Aquatic Ecologist Jesse Smith recently completed the U.S. Fish and Wildlife Service's Fresh Water Mussel Identification Training at the National Conservation Training Center in West Virginia. Through hands-on laboratory training, Evan and Jesse developed their freshwater mussel identification skills and their knowledge of freshwater mussel species biology. Course participants were tasked with mastering approximately 100 of the most common freshwater mussel species in the United States. They also learned about proper freshwater mussel collection labeling, the internal and external anatomy and meristics of a freshwater mussel, and distributional maps as an aid to freshwater mussel identification. In a recently published press release, Tierra Curry, a senior scientist with the Center for Biological Diversity was quoted as saying, “The health of freshwater mussels directly reflects river health, so protecting the places where these mussels live will help all of us who rely on clean water. This is especially important now, when we see growing threats to clean water from climate change, agriculture and other sources.” Princeton Hydro is committed to protecting water quality, restoring habitats, and managing natural resources. Read about some of our recent projects and contact us to discuss how we can help you. To learn more about freshwater mussels, check out this video from U.S. Fish and Wildlife Service: [embed]https://youtu.be/OWjlwfx67eY?si=YLCmgt2Ry0GiQ6BQ[/embed] [visual-link-preview encoded="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"] … [post_title] => Restoring and Revitalizing Freshwater Mussels [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => freshwater-mussels [to_ping] => [pinged] => [post_modified] => 2025-11-04 02:21:08 [post_modified_gmt] => 2025-11-04 02:21:08 [post_content_filtered] => [post_parent] => 0 [guid] => http://www.princetonhydro.com/blog/?p=2334 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [5] => WP_Post Object ( [ID] => 5808 [post_author] => 3 [post_date] => 2018-06-27 17:54:33 [post_date_gmt] => 2018-06-27 17:54:33 [post_content] => [video width="1920" height="1080" poster="https://princetonhydro.com/wp-content/uploads/2018/06/iron_on_the_concrete.jpg" autoplay="true"][/video] VIDEO: "Columbia Lake Dam when the water level was 18 inches to 2 feet lower" Video courtesy of Matt Hencheck In Northwest New Jersey on the Paulins Kill, an important tributary to the Delaware River, the century-old hydroelectric Columbia Dam is actively being removed. Princeton Hydro was contracted by American Rivers to investigate, design, and apply for permits for the removal of this dam for the New Jersey chapter of The Nature Conservancy. Our team of engineers and ecologists studied the feasibility of removal by collecting sediment samples, performing bioassay tests, and conducting a hydraulic analysis of upstream and downstream conditions. We’re excited to report that the Columbia Dam removal has officially commenced! The New Jersey Department of Environmental Protection started draining water from Columbia Lake a few weeks ago, which was the first step in removing the dam. Princeton Hydro has subsequently been contracted by The Nature Conservancy to provide construction administration services. Photos below show the water at lowered levels at the impoundments. Last week, the first hammer hit the wall of a downstream dam remnant, officially starting the removal process. The dam removal process will last a few weeks, as the contractor actively knocks down the thick concrete wall. Once the dam is removed, there is a high probability that populations of American Shad and River Herring will be restored. It may also enhance American Eel migration. As a coldwater fishery, this reach also has significant potential for trout species, as well as Smallmouth Bass. "It is very exciting to be a part of such a monumental effort for the restoration of the Paulins Kill. This river, once a major migration route for diadromous fish like American Shad, will once again be a nursery for this Delaware River icon," said Geoffrey Goll, PE, President and co-founder of Princeton Hydro. "The removal of these dams will also restore the functions and values of a riparian corridor and floodplain, eliminate costs to the taxpayer for the maintenance of a dam and lake, and provide additional riverine recreational opportunities. I expect to see the same resilience and positive impact to the Delaware River as the recent barrier removals on another major NJ tributary, the Musconetcong River. It is a win-win for NJ, and with The Nature Conservancy at the helm and expert guidance from American Rivers, it has been an experience of a career." This project could not have been possible without the hard work and dedication of the following partner organizations: The Nature Conservancy of New Jersey, American Rivers, U.S. Fish and Wildlife Service, RiverLogic Solutions, NJDEP Division of Fish and Wildlife Service, and SumCo EcoContracting. Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of a dozens of small and large dams in the Northeast. Click here to learn more about our fish passage and dam removal engineering projects. [post_title] => PHOTOS: Columbia Dam Lake Removal [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => photos-columbia-dam-removal [to_ping] => [pinged] => [post_modified] => 2026-04-02 16:28:05 [post_modified_gmt] => 2026-04-02 16:28:05 [post_content_filtered] => [post_parent] => 0 [guid] => http://www.princetonhydro.com/blog/?p=2127 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [6] => WP_Post Object ( [ID] => 2093 [post_author] => 3 [post_date] => 2018-06-26 18:00:32 [post_date_gmt] => 2018-06-26 18:00:32 [post_content] => The Moosup River is a beautiful 30-mile-long, trout river flowing through Connecticut and Rhode Island, eventually emptying into the Quinebaug River. Several dams, most originally built in the 1800s or early 1900s, impeded the river’s natural flow, impaired habitat, fragmented the river system, and prevented fish from swimming upstream to their native spawning grounds. In 2013, American Rivers, CTDEEP Fisheries, and Natural Resources Conservation Service began collaborating on the removal of multiple dams and remnant dams as part of a larger project to restore connectivity to the Moosup River in the Town of Plainfield. Princeton Hydro and RiverLogic Solutions were contracted to provide design-build and permitting services. As part of this larger multi-year effort, five dams are planned for removal from the Moosup River. The most downstream barrier, the Hale Factory Dam was removed in 2014. The remnants of the toppled Griswold Rubber Dam were removed in 2015. In 2017, the removal of Brunswick Mill Dam #1 was completed. And, two more dams, downstream of New Brunswick Mill Dam #1, are currently under consideration for removal. When fully completed, the Moosup River Dam Removal Project will reconnect fish habitats along 6.9 miles of the Moosup River. Hale Factory Dam The Hale Factory Dam was constructed of a boulder core capped in a one-foot-thick concrete layer. The dam was partially breached as the concrete cap had deteriorated severely over the years, allowing flow to pass between boulders and allowing the normal pool elevation to drop substantially from its former design height. The resource delineation conducted on site identified a vernal pool with an 18 inch culvert outlet that discharged 90 feet upstream of the dam. To preserve this ecological resource on the site, the vernal pool was not disturbed during the dam removal. Princeton Hydro provided a field assessment, sediment characterization and analysis, final design and permit application package for the full removal of the Hale Factory Dam. Full removal of the dam entailed demolition and removal of the concrete, and re-use of the natural cobbles and boulders from the dam to create in-stream habitat features. Once completed, the river and its boulders appeared as if placed by nature itself, with the former dam’s presence indicated only by the age-old lichen covered field stone walls leading up to the banks. Griswold Rubber Dam The Griswold Rubber Dam was in a gravel-cobble reach of the river approximately 80 feet wide in the Village of Moosup and was adjacent to the 1992 expansion of the Griswold Rubber factory. At one time, the dam stood approximately 10 feet high and 150 feet long. The dam was constructed of a large segmented concrete slab that had since toppled over and was lying nearly flat on the river bed in multiple sections. The dam structure, having failed, served no useful purpose. Despite being toppled, the dam still presented a deterrent to the effective movement of aquatic organisms at normal to low flows and was therefore worthy of complete removal to restore river connectivity. Princeton Hydro conducted an initial field investigation with RiverLogic Solutions to gain insights regarding the construction approach. Princeton Hydro then followed-up with a more detailed assessment of river bed sediment, geomorphic conditions, the likely riverine response, construction access, and other design related issues that were incorporated into design plans and permit applications. The restoration design Princeton Hydro developed aimed to remove the partial barrier to fish passage with as little disturbance to surrounding infrastructure and resources as possible. Brunswick Mill Dam #1 This dilapidated timber crib dam stood approximately 4-feet high and spanned the channel at approximately 130 feet. The timbers ranged from 1.5 to 2.5 feet in diameter and over 20 feet in length; 50 were integrated into the dam. The timber crib was filled with gravel and other debris, and the gravel substrate extended 50 feet upstream. The original dam was significantly higher, but the timber crib spillway deteriorated and gradually collapsed over time and only a portion of the structure remained. For this project, Princeton Hydro completed sediment investigation, sampling and analysis; hydrologic and hydraulic analysis; and provided design and engineering for full removal of the dam. Princeton Hydro contracted with an archeologist / industrial historian, and together closely observed the dam deconstruction to observe and record how the timber crib had been assembled. Multiple types of iron pins and wooden pegs revealed how the dam had been repaired over the years – findings, old maps, and photos were incorporated into a historical report filed with the state historic preservation office. Princeton Hydro coordinated to have the old timbers salvaged for eventual re-use. Removing the Brunswick Mill Dam #1 was a continuation of the large scale Moosup River restoration effort and paved the way for the potential removal of two more dams downstream in the coming years. "When a dam is breached and taken out, the tangible results are very quickly noticeable," said Paul Woodworth, Princeton Hydro Fluvial Geomorphologist. “The return of migratory fish is a very strong indicator of the ecological benefits of dam removal - sometimes after a removal you can see fish immediately swimming upstream. Removing dams also improves safety in nearby communities, reestablishes the natural flow of sediment, improves water quality, provides new recreation opportunities, and restores habitats for fish and wildlife.” Click here to read more about Princeton Hydro’s engineering services for the restoration and removal of dams. [gallery link="file" ids="2104,2107,2102,2109,2116,2118,2117,2115,2120,2122,2121,2149"] … [post_title] => Dam Removal on the Moosup River [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => moosup-river-dam-removal [to_ping] => [pinged] => [post_modified] => 2026-01-08 15:12:42 [post_modified_gmt] => 2026-01-08 15:12:42 [post_content_filtered] => [post_parent] => 0 [guid] => http://www.princetonhydro.com/blog/?p=2093 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 1 [filter] => raw ) [7] => WP_Post Object ( [ID] => 1872 [post_author] => 3 [post_date] => 2018-05-10 14:15:00 [post_date_gmt] => 2018-05-10 14:15:00 [post_content] => For thousands of years, river herring swam from the Atlantic Ocean through the Long Island Sound and up the Noroton River to spawn each spring. Then, they returned to the ocean until the next spawning season. Back in the 1920s, President Dwight D. Eisenhower’s administration began connecting the country through a massive interstate highway system. As part of the infrastructure plan, hundreds of thousands of culverts were built across the U.S. with the intention of moving water quickly and efficiently. While that goal was met, many migratory fish and other aquatic organisms could not overcome the culverts’ high-velocity flows, shallow water depths, and perched outlets. This infrastructure prevented them from reaching their native migratory destinations. By the late 1950s, Interstate 95 cut through Connecticut’s coastal rivers, and culverts were installed to convey river flows. Alewives, American Shad, Blueback Herring, and other native fish species were unable to navigate the culverts. Their populations dwindled to the point where Connecticut, along with Rhode Island, Massachusetts, and North Carolina, instituted moratoriums on catching and keeping the valued forage fish. Along the Noroton River, three parallel concrete culverts, each 300-feet long, 13-feet wide and 7-feet in height were installed, completely blocking upstream fish passage. In order to restore important fish populations and revitalize the Noroton River, Save the Sound launched a project that reopened approximately seven miles of the river, allowing migratory fish populations to safely and easily travel through the culverts to reach their original spawning habitat upstream. The project is a collaboration among Save the Sound, Darien Land Trust, Connecticut Department of Energy and Environmental Protection (CTDEEP), Connecticut Department of Transportation, Princeton Hydro, and other partners. For the project, Princeton Hydro lead design engineering and guided the construction of the following elements to restore upstream fish passage:
Welcome to the latest edition of our Client Spotlight Blog Series! Each spotlight provides an inside look at our collaboration, teamwork, and accomplishments with a specific client. We value our client relationships and pride ourselves on forming strong ties with organizations that share our values of creating a better future for people and our planet.
The Musconetcong Watershed Association (MWA) is an independent, non-profit organization dedicated to protecting and improving the quality of the Musconetcong River and its watershed, including its natural and cultural resources. Members of the organization are part of a network of individuals, families, and companies that care about the Musconetcong River and its watershed, and are dedicated to improving the watershed resources through public education and awareness programs, river water quality monitoring, promotion of sustainable land management practices, and community involvement.
Princeton Hydro has been working with MWA in the areas of river restoration, dam removal, and engineering consulting since 2003. To develop this Client Spotlight, we collaborated with MWA's Executive Director Cindy Joerger and Communications Coordinator Karen Doerfer:
A: As a watershed association, we focus on a specific place. This includes the Musconetcong River, a National Wild and Scenic River, as well as the area’s cultural, historical, recreational, and natural resources. We take a watershed focus, seeking to monitor the river and upstream areas to ensure it maintains good water quality.
A: MWA values community. Our membership is mostly grassroots, including residents, riverfront landowners, farmers, and local businesses. We value the long-term community of people who have helped form the organization, improve the river, and protect the scenic and historic resources that make our watershed unique.
A: Princeton Hydro has helped MWA with dam removal projects since the very first one, the Gruendyke Mill Dam, which was an obsolete dam on the border of Hackettstown and Mount Olive. Since then, Princeton Hydro has helped with four other dam removal projects and is currently assisting in the removal and restoration of the Beatty’s Mill Dam in Hackettstown, providing engineering plans and project management support.
The dam removals in the lower Musconetcong River have created a free-flowing passage to the Delaware River, and the removal of the Hughesville Dam welcomed the return of American shad less than a year after its removal.
A: Princeton Hydro has provided MWA with dam removal services on the Musconetcong River, most notably, the removal of Hughesville Dam, which brought Secretary of the Interior, Sally Jewell, out for its notching. Princeton Hydro has also helped us with the engineering and design for the Musconetcong Island Park Project, which involves the demolition of a building in a Historic District and the replacement of new, safer stairs.
A: The Hughesville Dam removal saw many successes and a few challenges we had to overcome as a team. After the initial removal and restoration, we worked together on another streambank restoration project to further stabilize the streambank near the dam removal site. This dam removal restored over 5 miles of free-flowing river to the Delaware River and will help lay the groundwork for the Warren Glen Dam removal, which is the largest dam on the Musconetcong River.
A: MWA is still working to restore the Asbury Mill, which we plan to use as an educational and eco-tourism hub for the community, as well as a much-needed office space for our growing staff.
A: Working for such a small organization, it is easier and more gratifying to see the impact it's making. Our staff gets to see a lot of projects from start to finish, so it’s rewarding to be able to have your stamp on something you watched grow from its inception to conclusion.
A: In the upper watershed, we are hoping that Princeton Hydro, in concert with others, can continue to help guide improvements to the water quality of Lake Hopatcong. The lake acts as our headwaters and is the largest in New Jersey. Last year, it suffered a serious issue with Harmful Algal Blooms.
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Wreck Pond is a tidal pond located on the coast of the Atlantic Ocean in southern Monmouth County, New Jersey. The 73-acre pond, which was originally connected to the sea by a small and shifting inlet, got its name in the 1800s due to the numerous shipwrecks that occurred at the mouth of the inlet. The Sea Girt Lighthouse was built to prevent such accidents. In the 1930s, the inlet was filled in and an outfall pipe was installed, thus creating Wreck Pond. The outfall pipe allowed limited tidal exchange between Wreck Pond and the Atlantic Ocean.
In the 1960s, Wreck Pond flourished with wildlife and was a popular destination for recreational activities with tourists coming to the area mainly from New York City and western New Jersey. In the early spring, hundreds of river herring would migrate into Wreck Pond, travelling up its tributaries — Wreck Pond Brook, Hurleys Pond Brook and Hannabrand Brook — to spawn. During the summer, the pond was bustling with recreational activities like swimming, fishing, and sailing.
Over time, however, the combination of restricted tidal flow and pollution, attributable to increased development of the watershed, led to a number of environmental issues within the watershed, including impaired water quality, reduced fish populations, and flooding.
Throughout the Wreck Pond watershed, high stream velocities during flood conditions have caused the destabilization and erosion of stream banks, which has resulted in the loss of riparian vegetation and filling of wetlands. Discharge from Wreck Pond during heavy rains conveys nonpoint source pollutants that negatively impact nearby Spring Lake and Sea Girt beaches resulting in beach closings due to elevated bacteria counts. Watershed erosion and sediment transported with stormwater runoff has also contributed to excessive amounts of sedimentation and accumulations of settled sediment, not only within Wreck Pond, but at the outfall pipe as well. This sediment further impeded tidal flushing and the passage of anadromous fish into and out of Wreck Pond.
In 2012, Hurricane Sandy caused wide-spread destruction throughout New Jersey and the entire eastern seaboard. The storm event also caused a major breach of the Wreck Pond watershed’s dune beach system and failure of the outfall pipe. The breach formed a natural inlet next to the outfall pipe, recreating the connection to the Atlantic Ocean that once existed. This was the first time the inlet had been open since the 1930s, and the reopening cast a new light on the benefits of additional flow between the pond and the ocean.
Hurricane Sandy sparked a renewed interest in reducing flooding impacts throughout the watershed, including efforts to restore the water quality and ecology of Wreck Pond. The breach caused by Hurricane Sandy was not stable, and the inlet began to rapidly close due to the deposition of beach sand and the discharge of sediment from Wreck Pond and its watershed.
Princeton Hydro and HDR generated the data used to support the goals of the feasibility study through a USACE-approved model of Wreck Pond that examined the dynamics of Wreck Pond along with the water bodies directly upland, the watershed, and the offshore waters in the immediate vicinity of the ocean outfall. The model was calibrated and verified using available “normalized” tide data. Neighboring Deal Lake, which is also tidally connected to the ocean by a similar outfall pipe, was used as the "reference" waterbody. The Wreck Pond System model evaluated the hydraulic characteristics of Wreck Pond with and without the modified outfall pipe, computed pollutant inputs from the surrounding watershed, and predicted Wreck Pond's water quality and ecological response. The calibrated model was also used to investigate the effects and longevity of dredging and other waterway feature modifications.
As part of the study, Princeton Hydro and HDR completed hazardous, toxic, and radioactive waste (HTRW) and geotechnical investigations of Wreck Pond's sediment to assess potential flood damage reduction and ecological restoration efforts of the waterbody. The investigation included the progression of 10 sediment borings conducted within the main body of Wreck Pond, as well as primary tributaries to the pond. The borings, conducted under the supervision of our geotechnical staff, were progressed through the surgical accumulated sediment, not the underlying parent material. Samples were collected for analysis by Princeton Hydro’s AMRL-accredited (AASHTO Materials Reference Library) and USACE-certified laboratory. In accordance with NJDEP requirements, sediment samples were also forwarded to a subcontracted analytical laboratory for analysis of potential nonpoint source pollutants.
In the geotechnical laboratory, the samples were subjected to geotechnical indexing tests, including grain size, organic content, moisture content, and plasticity/liquid limits. For soil strength parameters, the in-field Standard Penetration Test (SPT), as well as laboratory unconfined compression tests, were performed on a clay sample to provide parameters for slope stability modeling.
The culvert construction and sediment dredging were completed at the end of 2016. Continued restoration efforts, informed and directed by the data developed through Princeton Hydro's feasibility study, are helping to reduce the risk of flooding to surrounding Wreck Pond communities, increase connectivity between the pond and ocean, and improve water quality. The overall result is a healthier, more diverse, and more resilient Wreck Pond ecosystem.
To learn more about our geotechnical engineering services, click here.
On the Paulins Kill, the 100-year old Columbia Lake Dam has almost been completely removed, and fish passage has been restored! Since the first cut was executed on the main dam in August, many exciting advances have been made towards restoring the Paulins Kill back to its natural state. Check out the video below, courtesy of the New Jersey Nature Conservancy Volunteer Drone Team.
Piece by piece, the dam was notched out throughout the fall season and is now completely removed with the exception of the dam apron, the horizontal concrete structure that sits downstream of the dam, and the section of the dam that sits below the riverbed. The part of the dam in the riverbed is now being removed all the way down to three feet under the ground. The full removal is estimated to be complete by mid-March. In mid-August, the first cut was widened to 80 feet, allowing for better management of high flows during storm events, which had been posing a challenge immediately following the first cut.
In late August, the installation of rock vanes at the Brugler Road Bridge began. Rock vanes are engineered, in-stream structures that help to stabilize a channel while enhancing aquatic habitat and movement.
The rock vanes installed at the Brugler Road Bridge site are cross vanes. Cross vanes consist of a set of boulders angled upstream on a river, with another section of smaller rocks placed upstream. The taller sections of the cross vanes deflect the streamflow away from the banks, decreasing scouring effects. Instead, the flow travels over the rock walls and concentrates down the center of the channel, creating a deep and elongated pool in the middle of the stream.
Velocities between the notches in the rock vanes were evaluated using a velocity meter in accordance with the design specifications originally proposed. Based on the U.S. Fish and Wildlife Service fish passage design criteria, velocities in the notches could not be greater than 8.25 feet per second. All of the velocity measurements in this rock vane were below the maximum thresholds, ensuring no blockage of fish passage is made through the vanes.
Since the removal of the dam began, vegetative growth from the natural seedbed of the upper impoundment has been observed (see photo below).
In October, scour protection installation commenced at the Warrington Road Bridge site. After the team conducted geotechnical test pits, they discovered that a concrete scour wall that slopes out to the Paulins Kill was present and deep enough to be able to install rock at the necessary depth. They also found that the existing gabions, caged baskets filled with rock or concrete often used to protect against erosion, were intact and could be left in place. The team installed four (4) feet of riprap under and around the bridge in the riverbed and tied it into the existing grade of the banks.
The original notch in the dam was lowered one foot per day starting in mid-December, reducing water surface elevations down to the apron elevation during the month of January.
To accommodate NJ Fish and Wildlife’s request for animal passage under the I-80 bridges, an area of the previously installed riprap on the northwest abutment wall was flattened out and filled in with river cobble. This path will promote wildlife movement under the bridge as opposed to through the existing tunnel.
Currently, rock vanes are being installed under the I-80 bridges specifically to enhance fish passage. These structures vary slightly from the rock vanes at the Brugler Road Bridge site, as they are designed to slow river flow, helping migrating fish travel upstream and traverse a 5-foot elevation difference in the streambed, much like a fish ladder.
These rock vanes are more than halfway completed and are on track to be finished in time for fish populations to make full use of them. The next steps are to finish the demolition of the dam and the construction of the fish passage rock vanes under the I-80 bridges, plant vegetation throughout the upper impoundment, create a recreational trail through the upper impoundment, and plan for fishing and boating access! Stay tuned for more exciting developments on this incredible project.
Thank you to our project partners: The Nature Conservancy, American Rivers, U.S. Fish and Wildlife Service, and NJDEP Division of Fish and Wildlife Service.
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Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of a dozens of small and large dams in the Northeast. To learn more about our fish passage and dam removal engineering services, visit: bit.ly/DamBarrier.
As dams age and decay, they can become public safety hazards, presenting a failure risk and flooding danger. According to American Rivers, “more than 90,000 dams in the country are no longer serving the purpose that they were built to provide decades or centuries ago.” Dam removal has increasingly become the best option for property owners who can no longer afford the rising cost of maintenance and repair work required to maintain these complex structures.
Dams can also cause environmental issues such as blocking the movement of fish and other aquatic species, inundating river habitat, impairing water quality, and altering the flow necessary to sustain river life. Removing nonfunctional, outdated dams can bring a river back to its natural state and significantly increase biodiversity for the surrounding watershed.
Currently, work is underway in Watertown, Connecticut to remove the Heminway Pond Dam, which restricts fish passage in Steele Brook, creates a pond with increased water temperatures and high bacterial levels due to high geese populations, and encourages deposition of iron precipitate in the stream channel just downstream of the dam.
Princeton Hydro designed the engineering plans, managed permitting and is now overseeing construction for the removal project. The removal of the Heminway Pond Dam is identified as an integral component in addressing water quality impairment between the dam and Echo Lake Road.
REMOVAL OF HEMINWAY POND DAM ON STEELE BROOK IN WATERTOWN UNDERWAY After almost 15 years of discussion and planning with the Town of Watertown and other partners, removal of Heminway Pond Dam on Steele Brook in Watertown finally got underway in early July. Though no longer functional, the dam and pond were originally constructed to supply water for a former thread/string mill. The Town acquired the dam and pond from the Siemon Company, the most recent owner, in 2007 with an eye towards removing the dam, restoring the river and converting the dewatered impoundment area into a passive recreation area, including an extension of the Steele Brook Greenway. With these goals in mind, the Town approached CT DEEP for help with removal of the dam. As it turns out, CT DEEP, has also had a strong interest in seeing this dam removed. It is anticipated that dam removal will improve the hydrology in this section of Steele Brook and eliminate a water quality impairment which manifests itself during hot weather and low flow conditions, as an orange-colored plume of water (due to iron precipitate) immediately downstream of the dam that impacts aquatic life. Dam removal would also benefit fisheries by restoring stream connectivity and habitat. Working towards these mutual goals, CT DEEP was able to provide federal CWA 319 nonpoint source grant funding to USDA NRCS to develop a watershed-based plan for Steele Brook to address nonpoint source impairments that includes a dam removal feasibility analysis for Heminway Pond Dam. Based on the recommendations in this plan, CT DEEP subsequently provided additional 319 grant funds to the Town of Watertown to hire a consultant to develop a dam removal design package, and assist with permitting and preparation. With the Town of Watertown as a strong and vested partner, CT DEEP is now helping this project over the finish line by providing a combination of 319 and SEP funds to accomplish the actual dam removal and restoration of Steele Brook. Dayton Construction Company is performing the construction and Princeton Hydro is the consultant overseeing the project on behalf of the Town. The Northwest Conservation District is also assisting with the project. It is anticipated that the majority of the work will be completed by this Fall. U.S. EPA, ACOE and CT DEEP have all played active roles with regard to permitting the project.
After almost 15 years of discussion and planning with the Town of Watertown and other partners, removal of Heminway Pond Dam on Steele Brook in Watertown finally got underway in early July. Though no longer functional, the dam and pond were originally constructed to supply water for a former thread/string mill. The Town acquired the dam and pond from the Siemon Company, the most recent owner, in 2007 with an eye towards removing the dam, restoring the river and converting the dewatered impoundment area into a passive recreation area, including an extension of the Steele Brook Greenway. With these goals in mind, the Town approached CT DEEP for help with removal of the dam.
As it turns out, CT DEEP, has also had a strong interest in seeing this dam removed. It is anticipated that dam removal will improve the hydrology in this section of Steele Brook and eliminate a water quality impairment which manifests itself during hot weather and low flow conditions, as an orange-colored plume of water (due to iron precipitate) immediately downstream of the dam that impacts aquatic life. Dam removal would also benefit fisheries by restoring stream connectivity and habitat.
Working towards these mutual goals, CT DEEP was able to provide federal CWA 319 nonpoint source grant funding to USDA NRCS to develop a watershed-based plan for Steele Brook to address nonpoint source impairments that includes a dam removal feasibility analysis for Heminway Pond Dam. Based on the recommendations in this plan, CT DEEP subsequently provided additional 319 grant funds to the Town of Watertown to hire a consultant to develop a dam removal design package, and assist with permitting and preparation.
With the Town of Watertown as a strong and vested partner, CT DEEP is now helping this project over the finish line by providing a combination of 319 and SEP funds to accomplish the actual dam removal and restoration of Steele Brook. Dayton Construction Company is performing the construction and Princeton Hydro is the consultant overseeing the project on behalf of the Town. The Northwest Conservation District is also assisting with the project. It is anticipated that the majority of the work will be completed by this Fall. U.S. EPA, ACOE and CT DEEP have all played active roles with regard to permitting the project.
Princeton Hydro has designed, permitted, and overseen the reconstruction, repair, and removal of dozens of small and large dams in the Northeast. Click here to read about a recent dam removal project the firm completed on the Moosup River.
Freshwater mussels are among the oldest living and second most diverse organisms on Earth with over 1,000 recognized species. Here in the eastern part of the U.S., we have more species of freshwater mussels than anywhere in the world. Unfortunately, freshwater mussels are one of the most rapidly declining animal groups in North America. Out of the 300 species and subspecies found on the continent, 70 (23%) have been federally listed as "Threatened" or "Endangered" under the Endangered Species Act. And, in the last century, over 30 species have become permanently extinct. So, why are populations declining so fast?
Freshwater mussels are filter feeders and process large volumes of the water they live in to obtain food. This means of survival also makes them highly susceptible to industrial and agricultural water pollution. Because they are constantly filtering water, the contaminants and pathogens that are present are absorbed into the mussel’s tissues. As such, mussels are good indicators of water quality and can greatly contribute to improving water quality by filtering algae, bacteria and organic matter from the water column.
Not only do freshwater mussels rely on water quality, they are dependent on fish and other aquatic organisms for reproductive success. In order for a freshwater mussel to complete the reproduction process, it must “infect” a host fish with its larvae. The method depends on the specie of mussel. Some species lure fish using highly modified and evolved appendages that mimic prey. When a fish goes into investigate the lures, the female mussel releases fertilized eggs that attach to the fish, becoming temporarily parasitic. Once the host fish is infected, it can transfer the mussel larvae upstream and into new areas of the river.
Both habitat loss from dam construction and the introduction of pesticides into the water supply has contributed to the decline of freshwater mussels. With approximately 300 mussel species in the U.S. alone, a critical component of restoring and revitalizing mussel populations is truly understanding their biology, which begins with the ability to properly differentiate each species and properly identify and catalog them. Princeton Hydro’s Senior Scientist Evan Kwityn, CLP and Aquatic Ecologist Jesse Smith recently completed the U.S. Fish and Wildlife Service's Fresh Water Mussel Identification Training at the National Conservation Training Center in West Virginia.
Through hands-on laboratory training, Evan and Jesse developed their freshwater mussel identification skills and their knowledge of freshwater mussel species biology. Course participants were tasked with mastering approximately 100 of the most common freshwater mussel species in the United States. They also learned about proper freshwater mussel collection labeling, the internal and external anatomy and meristics of a freshwater mussel, and distributional maps as an aid to freshwater mussel identification.
In a recently published press release, Tierra Curry, a senior scientist with the Center for Biological Diversity was quoted as saying, “The health of freshwater mussels directly reflects river health, so protecting the places where these mussels live will help all of us who rely on clean water. This is especially important now, when we see growing threats to clean water from climate change, agriculture and other sources.”
Princeton Hydro is committed to protecting water quality, restoring habitats, and managing natural resources. Read about some of our recent projects and contact us to discuss how we can help you.
To learn more about freshwater mussels, check out this video from U.S. Fish and Wildlife Service:
VIDEO: "Columbia Lake Dam when the water level was 18 inches to 2 feet lower" Video courtesy of Matt Hencheck
The Moosup River is a beautiful 30-mile-long, trout river flowing through Connecticut and Rhode Island, eventually emptying into the Quinebaug River.
Several dams, most originally built in the 1800s or early 1900s, impeded the river’s natural flow, impaired habitat, fragmented the river system, and prevented fish from swimming upstream to their native spawning grounds.
In 2013, American Rivers, CTDEEP Fisheries, and Natural Resources Conservation Service began collaborating on the removal of multiple dams and remnant dams as part of a larger project to restore connectivity to the Moosup River in the Town of Plainfield. Princeton Hydro and RiverLogic Solutions were contracted to provide design-build and permitting services.
As part of this larger multi-year effort, five dams are planned for removal from the Moosup River. The most downstream barrier, the Hale Factory Dam was removed in 2014. The remnants of the toppled Griswold Rubber Dam were removed in 2015. In 2017, the removal of Brunswick Mill Dam #1 was completed. And, two more dams, downstream of New Brunswick Mill Dam #1, are currently under consideration for removal. When fully completed, the Moosup River Dam Removal Project will reconnect fish habitats along 6.9 miles of the Moosup River.
The Hale Factory Dam was constructed of a boulder core capped in a one-foot-thick concrete layer. The dam was partially breached as the concrete cap had deteriorated severely over the years, allowing flow to pass between boulders and allowing the normal pool elevation to drop substantially from its former design height.
The resource delineation conducted on site identified a vernal pool with an 18 inch culvert outlet that discharged 90 feet upstream of the dam. To preserve this ecological resource on the site, the vernal pool was not disturbed during the dam removal.
Princeton Hydro provided a field assessment, sediment characterization and analysis, final design and permit application package for the full removal of the Hale Factory Dam. Full removal of the dam entailed demolition and removal of the concrete, and re-use of the natural cobbles and boulders from the dam to create in-stream habitat features. Once completed, the river and its boulders appeared as if placed by nature itself, with the former dam’s presence indicated only by the age-old lichen covered field stone walls leading up to the banks.
The Griswold Rubber Dam was in a gravel-cobble reach of the river approximately 80 feet wide in the Village of Moosup and was adjacent to the 1992 expansion of the Griswold Rubber factory. At one time, the dam stood approximately 10 feet high and 150 feet long. The dam was constructed of a large segmented concrete slab that had since toppled over and was lying nearly flat on the river bed in multiple sections. The dam structure, having failed, served no useful purpose. Despite being toppled, the dam still presented a deterrent to the effective movement of aquatic organisms at normal to low flows and was therefore worthy of complete removal to restore river connectivity.
Princeton Hydro conducted an initial field investigation with RiverLogic Solutions to gain insights regarding the construction approach. Princeton Hydro then followed-up with a more detailed assessment of river bed sediment, geomorphic conditions, the likely riverine response, construction access, and other design related issues that were incorporated into design plans and permit applications. The restoration design Princeton Hydro developed aimed to remove the partial barrier to fish passage with as little disturbance to surrounding infrastructure and resources as possible.
This dilapidated timber crib dam stood approximately 4-feet high and spanned the channel at approximately 130 feet. The timbers ranged from 1.5 to 2.5 feet in diameter and over 20 feet in length; 50 were integrated into the dam. The timber crib was filled with gravel and other debris, and the gravel substrate extended 50 feet upstream. The original dam was significantly higher, but the timber crib spillway deteriorated and gradually collapsed over time and only a portion of the structure remained.
For this project, Princeton Hydro completed sediment investigation, sampling and analysis; hydrologic and hydraulic analysis; and provided design and engineering for full removal of the dam. Princeton Hydro contracted with an archeologist / industrial historian, and together closely observed the dam deconstruction to observe and record how the timber crib had been assembled. Multiple types of iron pins and wooden pegs revealed how the dam had been repaired over the years – findings, old maps, and photos were incorporated into a historical report filed with the state historic preservation office. Princeton Hydro coordinated to have the old timbers salvaged for eventual re-use. Removing the Brunswick Mill Dam #1 was a continuation of the large scale Moosup River restoration effort and paved the way for the potential removal of two more dams downstream in the coming years.
"When a dam is breached and taken out, the tangible results are very quickly noticeable," said Paul Woodworth, Princeton Hydro Fluvial Geomorphologist. “The return of migratory fish is a very strong indicator of the ecological benefits of dam removal - sometimes after a removal you can see fish immediately swimming upstream. Removing dams also improves safety in nearby communities, reestablishes the natural flow of sediment, improves water quality, provides new recreation opportunities, and restores habitats for fish and wildlife.”
Click here to read more about Princeton Hydro’s engineering services for the restoration and removal of dams.
For thousands of years, river herring swam from the Atlantic Ocean through the Long Island Sound and up the Noroton River to spawn each spring. Then, they returned to the ocean until the next spawning season.
Back in the 1920s, President Dwight D. Eisenhower’s administration began connecting the country through a massive interstate highway system. As part of the infrastructure plan, hundreds of thousands of culverts were built across the U.S. with the intention of moving water quickly and efficiently. While that goal was met, many migratory fish and other aquatic organisms could not overcome the culverts’ high-velocity flows, shallow water depths, and perched outlets. This infrastructure prevented them from reaching their native migratory destinations.
By the late 1950s, Interstate 95 cut through Connecticut’s coastal rivers, and culverts were installed to convey river flows. Alewives, American Shad, Blueback Herring, and other native fish species were unable to navigate the culverts. Their populations dwindled to the point where Connecticut, along with Rhode Island, Massachusetts, and North Carolina, instituted moratoriums on catching and keeping the valued forage fish.
Along the Noroton River, three parallel concrete culverts, each 300-feet long, 13-feet wide and 7-feet in height were installed, completely blocking upstream fish passage. In order to restore important fish populations and revitalize the Noroton River, Save the Sound launched a project that reopened approximately seven miles of the river, allowing migratory fish populations to safely and easily travel through the culverts to reach their original spawning habitat upstream.
The project is a collaboration among Save the Sound, Darien Land Trust, Connecticut Department of Energy and Environmental Protection (CTDEEP), Connecticut Department of Transportation, Princeton Hydro, and other partners. For the project, Princeton Hydro lead design engineering and guided the construction of the following elements to restore upstream fish passage:
Reopening river passage for migratory species will improve not only the health of the Noroton River itself, but will also benefit the overall ecosystem of Long Island Sound. Over the last decade, fish passage projects around the sound’s Connecticut and New York shores have dramatically increased freshwater spawning habitat for the foundational species whose return is restoring a more vibrant food web to the Long Island Sound.
Construction of the baffles and rock ramp were completed in time for the 2018 migratory season. Construction of the concrete weir is on temporary hold for low-flow conditions. On April 26, 2018, project partners gathered for a project celebration and the release of migratory fish by CTDEEP at an upstream location.
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