Part One: Damned If You Do, Dammed If You Don’t: Making Decisions and Resolving Conflicts on Dam Removal

People have been building dams since prerecorded history for a wide variety of economically valuable purposes including water supply, flood control, and hydroelectric power. Back in the 1950s and 60s, the U.S. saw a boom in infrastructure development, and dams were being built with little regard to their impacts on rivers and the environment. By the 1970’s, the rapid progression of dam building in the U.S. led researchers to start investigating the ecological impacts of dams. Results from these early studies eventually fueled the start of proactive dam removal activities throughout the U.S.

Despite the proven benefits of dam removal, conflicts are a prevalent part of any dam removal project. Dam removal, like any other social decision-making process, brings up tensions around economics and the distribution of real and perceived gains and losses. In this two part blog series, we take a look at addressing and preventing potential conflicts and the key factors involved in dam removal decision-making – to remove or not to remove.

Why We Remove Dams

The primary reasons we remove dams are safety, economics, ecology, and regulatory. There has been a growing movement to remove dams where the costs – including environmental, safety, and socio-cultural impacts – outweigh the benefits of the dam or where the dam no longer serves any useful purpose. In some cases, it’s more beneficial economically to remove a dam than to keep it, even if it still produces revenue. Sometimes the estimated cost of inspection, repair, and maintenance can significantly exceed the cost of removal, rendering generated projected revenue insignificant.

Safety reasons are also vital, especially for cases in which dams are aging, yet still holding large amounts of water or impounded sediment. As dam’s 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.

The goal of removal can be multi-faceted, including saving taxpayer money; restoring flows for migrating fish, other aquatic organisms, and wildlife; reinstating the natural sediment and nutrient flow; eliminating safety risks; and restoring opportunities for riverine recreation.

Moosup River

Common Obstacles to Dam Removal

Dam removal efforts are often subjected to a number of different obstacles that can postpone or even halt the process altogether. Reasons for retaining dams often involve: aesthetics and reservoir recreation; water intakes/diversions; hydroelectric; quantity/quality of sediment; funding issues; cultural/historic values of manmade structures; owner buy-in; sensitive species; and community politics.

Of those common restoration obstacles, one of the more frequently encountered challenges is cost and funding. Determining who pays for the removal of a dam is often a complex issue. Sometimes, removal can be financed by the dam owner, local, state, and federal governments, and in some cases agreements are made whereby multiple stakeholders contribute to cover the costs. Funding for dam removal projects can be difficult to obtain because it typically has to come from a variety of sources.

Anecdotally, opposition also stems from fear of change and fear of the unknown. Bruce Babbitt, the United States Secretary of the Interior from 1993 through 2001 and dam removal advocate, said in an article he wrote, titled A River Runs Against It: America’s Evolving View of Dams, “I always wonder what is it about the sound of a sledgehammer on concrete that evokes such a reaction? We routinely demolish buildings that have served their purpose or when there is a better use for the land. Why not dams? For whatever reason, we view dams as akin to the pyramids of Egypt—a permanent part of the landscape, timeless monuments to our civilization and technology.”

Negative public perceptions of dam removal and its consequences can seriously impede removal projects. Although there are many reasons for the resistance to dam removal, it is important that each be understood and addressed in order to find solutions that fulfill both the needs of the environment and the local communities.

Stay tuned for Part Two of this blog series in which we explore strategies for analyzing dams and what goes into deciding if a dam should remain or be removed.

Spring Events Spotlights: Earth Day, Arbor Day, Conferences, & More!

Princeton Hydro is participating in lots of interesting events this Spring; here’s a snapshot of what’s to come:

 April 22, 2019:  Slade Dale Restoration Volunteer Day

Celebrate Earth Day a few days early with a fun Jersey Shore volunteer event! The American Littoral Society, in partnership with Princeton Hydro, Borough of Point Pleasant, and the local Rotary Club, is organizing dozens of volunteers to restore the shoreline and prevent further erosion at the Slade Dale Sanctuary using recycled Christmas trees, a technique that is groundbreaking for New Jersey.  Help us transport donated/recycled Christmas trees to the marsh to breakwater sections, stuffed them between the pilings, and securely tie them down. The volunteer is from 10 AM to 4 PM and water and light refreshments will be served.  Dress to get wet and mess and don’t forget to bring sunscreen, lunch, and waders (if you have them!). Street parking is available along Sea Point Drive.

Register here.

 

April 25, 2019: Arbor Day Celebration with Friends of Exton

We’re celebrating Arbor Day with Friends of Exton Park! Join us on Thursday, April 25 for a bird walk and native tree and shrub planting. During the bird walk, which runs from 8:30 – 10:30 am, we hope to spot spring migrants. Planting will take place between 10:30 am and 12:30 pm, and then lunch will be provided.

We hope you’ll join us for a fun and productive day in Exton Park. Birders and nature enthusiasts of all skill levels are welcome!

RSVP here: friendsofextonpark@gmail.com 

 

May 1, 2019:  SAME NJ POST 2019 Small Business Council Breakfast 

Princeton Hydro is proud to be attending, sponsoring, and our Communications Strategist Dana Patterson is emceeing this year’s Society for American Military Engineers (SAME) NJ Post 2019 Small Business Council Breakfast, which is being held at the Forsgate Country Club in Monroe. The program consists of networking opportunities, a variety of speakers, and breakfast (of course!). SAME gives leaders from the A/E/C, environmental, and facility management industries the opportunity to come together with federal agencies in order to showcase best practices and highlight future opportunities for small businesses to work in the federal market.

May 3-4, 2019: New York State Federation of Lake Associations Annual Conference

New York State Federation of Lake Associations (NYSFOLA) will host its 36th Annual Conference May 3-4 at the Fort William Henry Conference Center in Lake George. This year’s conference, which is titled, “Empowering Lake Associations in Challenging Times,” will feature a diverse exhibitor hall, networking opportunities, a silent auction and a variety of educational sessions. Princeton Hydro is exhibiting and giving presentations on the following topics:

    • Development of a HABS/Cyanotoxin Management Plan by Dr. Fred Lubnow, Director of Aquatics
    • A Layman’s Guide on How Land Practices Impact Water Quality by Chris Mikolajczyk, CLM, Senior Aquatic Scientist
    • Dr. Stephen Souza, a founding principal of our firm, is giving two presentations: “Small Footprint Green Infrastructure Stormwater Management for Lake Communities” and  “Impacts of Carp on Water Quality.”
Learn More & Register

 

May 4, 2019: 10th Annual Sustainable South Jersey Earth Festival

Hosted by the nonprofit Sustainable South Jersey, the Sustainable South Jersey Earth Festival is the largest eco-event in the region, drawing 5000 visitors annually. This year’s festival is themed “Reduce Plastic – Fantastic!” and will feature a family-fun bike ride, musical entertainment, perennial native plant swap, exhibits from a variety of earth-friendly, eco-conscious vendors, outdoor arts & crafts, and more. Admission is free and everyone is welcome to attend. Advanced registration is required for the family-fun bike ride. Our Communications Strategist Dana Patterson recently joined the board of Sustainable South Jersey, and will be hopping around the event. We hope to see you there!

Learn More & Register to Ride

 

May 28, 2019: REI Inspirational Women Speaker Series: Restoring Nature
Engineers and dam removal experts Sally Harold, Director of River Restoration & Fish Passage for the Nature Conservancy;  Gwen Macdonald, Director of Green Projects for Save the Sound; and our very own Laura Wildman, PE will join together at the West Hartford REI to discuss their unique skills and passions around river restoration and dam removal, and provide tips on how to get started with environmental efforts in your community. Registration is required for this free event, all are welcome.
Learn More & Register

Study Data Leads to Healthier Wreck Pond Ecosystem

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.

American Littoral Society

 

To learn more about our geotechnical engineering services, click here.

Dam Removal Underway in Watertown, Connecticut

Deconstruction of the Heminway Pond Dam, Watertown, CT on July 16, 2018.

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.

A view from the site of the Heminway Pond Dam removal on July 19, 2018.

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

Upstream at rock-filled breach in Heminway Pond Dam and shallow, dewatered impoundment on Steele Brook in Watertown (7-18-18)

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.

 

A view of the first notch during the Heminway Pond Dam removal on July 17, 2018.

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. And, to learn more about our dam and barrier engineering services, visit: bit.ly/DamBarrier.

Restoring and Revitalizing Freshwater Mussels

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:

Lithuania Hosts First-ever Dam Removal Workshop Feat. Princeton Hydro Expert

Lithuania Hosts its First-Ever
Dam Removal Workshop

Princeton Hydro’s Laura Wildman Invited to Present

History was recently made in Lithuania with the occurrence of the first-ever dam removal workshop held in the country. Experts throughout the world convened at the Ministry of Environment in Vilnius, the capital of Lithuania, to lead discussions on a variety of topics related to dam removal and river rehabilitation.  They covered the current state of affairs regarding Lithuanian dams and showcased the Dam Removal Europe (DRE) initiative, a new effort aimed at restoring rivers in Europe.

The workshop was the brainchild of Lithuanian environmental activist Karolina Gurjazkaitė. She read about the DRE campaign and was so inspired by the initiative, she contacted DRE representatives about organizing the workshop. Her goals in organizing the first-ever dam removal workshop in Lithuania were to build awareness around the importance of river restoration, call attention to the many outdated, unmaintained, and unnecessary dams throughout Lithuania, and ultimately inspire positive changes in the way of dam removals and river rehabilitation.

“I am very excited, not only about the workshop, but also about the ‘side effects’…already created,” said Karolina. “People are gaining hopes and enthusiasm… This workshop may have really powerful outcomes!”

Karolina gathered a diverse group of workshop attendees, comprised of government officials (including the Vice-Minister of Environment of Lithuania), university professors (primarily specializing in dam safety and hydropower development), local environmental advocates and NGO volunteers, researchers, and students.

Presenters during the workshop included scientists, engineers, communication experts, planners, activists, and Princeton Hydro’s New England Regional Office Director and Fisheries Engineer Laura Wildman, P.E.

Presentations covered a wide variety of topics, including:

  • Policy and current situation in Europe: Pao Fernández Garrido of World Fish Migration Foundation, Spain presented on DRE findings related to policy and the current dam removal situation in Europe.

  • Research: Rachel Bowes from Karlstad University, Sweden spoke about current state of affairs with Swedish dam removal efforts and the research they are currently carrying out.

  • Book presentation: Herman Wanningen of World Fish Migration Foundation, Netherlands presented the new book, From Sea to Source 2.0, which is focused on tackling the challenges of restoring fish migration in rivers around the world and is available for free download.

  • Technical issues: Laura Wildman, PE, who has over 20 years of experience on dam removal, presented on the most important technical aspects when carrying out a barrier demolition.

On day two of the workshop, participants were invited to take part in field visits to five dam sites. Each of the five dams all presented their own unique challenges in terms of the ability to remove them. The site visits provided a deeper look into the challenges that will need to be addressed when forging ahead with a Lithuanian river restoration initiative.

The workshop proved to be instrumental in identifying key challenges and next steps in building a successful country-wide river rehabilitation initiative. One of the key takeaways from the workshop is the need for a more robust understanding of Lithuanian-specific rules and regulations that classify a dam removal project as either viable or not viable.

“Not only has there never been a dam removal workshop held in Lithuania, to date, a dam removal has never been completed in Lithuania, at least none that have been documented and none for environmental restoration reasons,” said Laura. “It’s clear that we still have a lot to explore and discover, but I am so thrilled to have been a part of this workshop. It was a very positive first step in the right direction, and I’m looking forward to watching and helping this initiative flourish.”

To learn more about Princeton Hydro’s dam removal and river restoration initiatives, go here.

 

PHOTOS: Columbia Dam Removal

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.

“Dewatering Impoundment” Photo by Princeton Hydro

“An aerial drone snapshot when water levels were down about 5 feet at the upper impoundment” Photo courtesy of the New Jersey Chapter of The Nature Conservancy

Last week, the first hammer hit the wall of a downstream dam remnant, officially starting the removal process.

“The first hammer”  Photo courtesy of Dale Bentz, RiverLogic Solutions

The dam removal process will last a few weeks, as the contractor actively knocks down the thick concrete wall.

“Pressure and time”  Photo courtesy of Dale Bentz, RiverLogic Solutions

“Halfway there”  Photo courtesy of Dale Bentz, RiverLogic Solutions

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.

(Top) Before: Photo of the Columbia Dam before construction. (Bottom) After: Princeton Hydro’s rendering of what the river will look like once the dam is removed.

“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. To learn more about our fish passage and dam removal engineering services, visitbit.ly/DamBarrier.


This video from 2016 features the Nature Conservancy’s New Jersey State Director Barbara Brummer, Ph.D. speaking on the Columbia Dam removal. Video credit: NJ Herald.

Dam Removal on the Moosup River

Moosup River

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.

New Book Aims to Protect and Restore Fish Migrations

Rivers are a critical natural resource and an essential element for the health and survival of billions of people and countless species. Flourishing populations of migratory fish are an important indicator of a healthy, coastally connected river and a robust aquatic ecosystem as a whole. Migratory fish help to maintain a balanced food web, support productive river systems, and provide income for people around the world.

Yet many migratory fish species are severely threatened primarily due to man-made obstacles like dams and weirs, which disrupt the natural flow of rivers and prevent fish migration. When fish can’t reach their habitat, they can’t reproduce and maintain their populations.

Photo Credit: “From Sea to Source 2.0”

A new book, titled From Sea to Source 2.0, explores the challenges that lie behind restoration of fish migration in rivers around the world and provides a practical guide to promoting the protection and restoration of fish migration. The book is a unique collaboration of over 100 international fisheries professionals and supported by river managers, governments, research institutes and NGOs including World Wildlife Fund and The Nature Conservancy. Geared toward practitioners, but also a wonderful resource for the general public, the book is comprised of inspiring stories from nearly every continent on the planet. Click here to download it for free.

“Ultimately our ambition is to contribute in a positive way to making a better world and a positive difference for migratory fish, nature and humans on local and global levels by inspiring new initiatives for and with people all around the world,” as stated on www.fromseatosource.com. “Whether the challenge is simply to increase access to spawning habitats through connectivity improvements for salmon, or to maintain the livelihoods for hundreds of millions of people dependent upon fish and fisheries in the great rivers of Asia, Africa and South America, we hoped our book would help to achieve these goals.”

Princeton Hydro’s Dam Removal Expert Laura Wildman, P.E. and Fluvial Geomorphologist Paul Woodworth are proud contributors to the book, helping to write the dam removal chapter, creating a dam removal flow chart for the book, and providing multiple photos utilized in the book. Princeton Hydro is also listed as a contributing sponsor.

“We’re so proud to be part of this incredible project with so many partners globally,” said Wildman. “We envision that this book will provide a valuable resource and inspiration for those in countries and regions where the importance of restoring riverine connectivity is newly gaining momentum. We hope it will help emphasize the importance of finding balanced and environmentally informed solutions when proposing additional utilization of public trust resources such as rivers.”

Approximately 40% of all fish species in the world reside in freshwater ecosystems, contributing economic and ecological benefits and value. It’s critical that we support efforts that aim to protect migratory fish species, reconnect rivers, sustain fish passage, and preserve free-flowing rivers through removing unnecessary dams, reconnecting floodplains, managing our water use, and managing hydropower for sustainable rivers.

Education and awareness building are key first steps in protecting rivers. From Sea to Source 2.0 seeks to inform, educate and inspire those who want to know more about how to meet the challenges of restoring fish migration in rivers around the world.  The book is regarded as a crucial resource in the ongoing fight to protect and preserve the enormous value of our waterways.

Get your free copy here.

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.

Conservation Spotlight: Restoring Fish Passage on the Noroton River

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:

  • The installation of a concrete weir at the upstream end of the culvert to increase water depths in one culvert during low-flow periods;
  • The installation of concrete baffles to reduce flow velocities and create resting places for fish, and;
  • The installation of a naturalized, step-pool, rock ramp at the downstream end of the project to allow fish to ascend into the culvert gradually, overcoming the two-foot vertical drop present under existing conditions. The rock ramp consists of a grouted riverstone base with large grouted boulders arranged to make steps, with low-flow passage channels, between a series of pools approximately 1-foot deep that create resting places for upstream migrating fish.

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.

“It’s fascinating to feel the change in the flow patterns against your legs as you walk through the baffled culvert knowing that it will now facilitate fish passage through this restored reach,” said Princeton Hydro’s New England Regional Office Director and Water Resources and Fisheries Engineer Laura Wildman, P.E. “It is a very attractive and natural-looking fishway, and we’re proud to have created a design that fits so well into the surrounding landscape.”

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.