We’re committed to improving our ecosystems, quality of life, and communities for the better.
Our passion and commitment to the integration of innovative science and engineering drive us to exceed on behalf of every client.
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From advancing ecosystem restoration and water quality initiatives to sharing expertise on the global stage, these milestones showcase the dedication of our team and the strength of our partnerships. None of this would have been possible without the trust and support of our clients, collaborators, and community. Join us as we celebrate the Top 10 Successes of 2025: 1. Completed the Full Removal of 2 Dams: [gallery link="none" size="medium" ids="18228,18220,18224"] After more than a century of standing, the Paulina Lake Dam on the Paulins Kill River in Warren County, NJ, was fully removed, marking a transformative milestone for one of New Jersey’s largest tributaries to the Delaware River. Led by The Nature Conservancy New Jersey and funded by NJDEP Division of Fish and Wildlife, this multi-phase project concluded this summer with the third and final phase that included adaptive management work and habitat enhancements to boost biodiversity. We provided engineering design and oversight throughout the effort helping restore natural river flow and improve ecological resilience. On the Farmington River in Connecticut, the Winchell-Smith Dam was fully removed after more than a decade of planning and collaboration. Spearheaded by the Farmington River Watershed Association, this project reconnects 30 miles of critical upstream habitat, improving fish passage for species like American shad, alewife, and American eel. We contributed engineering, design, and project oversight, working alongside partners including Miss Porter’s School, CTDEEP Fisheries, and RiverLogic Solutions. The removal enhances ecological health, fish passage, public safety, and recreational opportunities along one of New England’s most celebrated rivers. 2. Secured $3.2 Million in Grant Funding for our Clients: We delivered incredible results for our nonprofit and government partners, securing over $3.2 million in funding to support projects that restore ecosystems, enhance habitats, improve water quality, and implement watershed-based green infrastructure and stormwater BMPs, with grants awarded through the National Fish and Wildlife Foundation’s Delaware Watershed Conservation Fund and Section 319(h) of the federal Clean Water Act, administered by NJDEP’s Watershed and Land Management Program. We assisted the Borough of Mountain Lakes in securing grant funding from the New Jersey Highlands Council to develop a comprehensive Lake and Watershed Management Plan for nine lakes within the Borough. Also noteworthy: of the 17 total 319(h) grants awarded statewide this year, we’re proud to be a partner on five, demonstrating our commitment to advancing watershed restoration and sustainability. 3. Launched an Innovative Initiative to Study HABs in the Delaware River Watershed: In partnership with Friends of Hopewell Valley Open Space, we kicked off a groundbreaking research project: “Monitoring Harmful Algal Blooms (HABs) in the Delaware River Watershed Using Drones and Spatial Analysis.” Funded by the National Fish and Wildlife Foundation through the Delaware Watershed Conservation Fund, this $1M initiative leverages drone technology, advanced data modeling, and community science to improve forecasting and management of HABs across a 73-mile stretch of the Delaware River and 23 associated waterbodies. We conceptualized and designed the project and are leading technical implementation, including field survey design, drone operations, data analysis, and volunteer training. By integrating drone-based remote sensing, on-the-water sampling, and spatial analysis, we aim to develop predictive tools for early detection and mitigation of HABs, helping protect drinking water supplies, wildlife, and local economies. This collaborative effort includes partners such as NYC College of Technology, Trenton Water Works, Mercer County Park Commission, The College of New Jersey, Aqua-PA, Philadelphia Water Department, Bucks County Conservation District, and Turner Designs. Data collection began in August will resume in Spring/Summer 2026 and culminate in 2027 with a final report. 4. Earned 7 Prestigious Awards: Just this month, Princeton Hydro was honored with the Princeton Mercer Regional Chamber “Innovator of the Year” Award and President Geoffrey M. Goll, PE received the “Notable Achievement” Award from SAME New Jersey Post during their Annual Holiday Luncheon. Geoffrey also received a “Lifetime Achievement Award” from the New Jersey Highlands Coalition for his dedication to protecting and enhancing New Jersey’s environmental, cultural, and natural resources. For another year in row, Princeton Hydro was recognized as one of New Jersey’s “Top Workplaces of 2025.” In partnership with Warrington Township, our transformative ecological uplift initiative at Lion’s Pride Park won the 2025 Pennsylvania Governor’s Award for Environmental Excellence. We were selected as the recipient of the Friends of Hopewell Valley Open Space “Corporate Conservation Recognition" Award, a distinction that celebrates our long-standing dedication to advancing ecological resilience through science-based, innovative solutions. And, along with Crow Holdings, we were chosen for the United Away "Spirit of Philanthropy” Award. 5. Constructed 2 Transformative Ecosystem Restoration Projects: In New York, we completed the Spring Creek North Ecosystem Restoration Project, revitalizing 43 acres of degraded habitat within the historic Jamaica Bay salt marsh system. The project restored a mosaic of ecosystems, including low marsh, high marsh, scrub-shrub wetland, and maritime upland, through activities like recontouring uplands to intertidal elevations, thin-layer sand placement, invasive species removal, and native plantings. This effort improves water quality, biodiversity, and wildlife habitat, contributing to the long-term health of Jamaica Bay. In the Meadowlands of New Jersey, we helped design and build the Steven R. Rothman Overlook and Preserve, a new five-acre public open space within the 587-acre Richard P. Kane Natural Area. The site offers ADA-accessible trails, sweeping views of the Meadowlands and NYC skyline, and a gateway into one of the state’s most ecologically significant landscapes along the Atlantic Flyway. We provided environmental, civil, and geotechnical engineering, landscape architecture, and construction oversight, ensuring the space honors decades of conservation work while creating opportunities for community connection and nature-based recreation. 6. Celebrated Numerous Staff Achievements: Our team continues to shine, reaching new heights in research, professional development, and industry leadership. Senior Wildlife Biologist Michael McGraw, CSE, QAWB, ACE co-authored a study published in Agriculture, Ecosystems & Environment, a leading journal in agroecological research, and was featured on the Native Plants, Healthy Planet podcast, a Top 20 Nature Apple podcast with over 7,000 monthly listeners. Senior Director of Field Services Scott Churm became a PRO Certified EutroSORB® Specialist, and Geotechnical Engineer Matthew Pappas, CSS earned the highly respected Certified Construction Specifier credential from the Construction Specifications Institute. We also welcomed five new team members: Controller Andy Ryba; Senior Water Resources Engineer Rich Farella, PE, CFM; Staff Engineer Patricia Hurley, EIT; Marketing & Proposal Manager Amie Souza, and Aquatics Project Manager Tanya Dapkey, CE who earned her ESA Certified Ecologist credential this year. Way to go, team! Your dedication and talent continue to inspire us all. 7. Partnered with Billion Oyster Project to Study Urban Reef Ecosystems: [gallery link="none" ids="18263,18265,18268"] Princeton Hydro teamed up with Billion Oyster Project, AKRF, and Monmouth University to explore how restored oyster reefs are revitalizing New York City’s waterways. The project, “Monitoring of Mobile Estuarine Organisms at Restored Oyster Reefs,” combines hands-on species surveys with cutting-edge environmental DNA (eDNA) analysis to capture a complete picture of reef biodiversity. As the field sampling lead, our team conducted monitoring at sites including Brooklyn Bridge Park, Bush Terminal Park, Flushing Bay, and Paedergat Basin. These efforts revealed a diverse array of estuarine life, from schooling fish to a surprise dogfish, and collected eDNA samples for advanced species detection. By integrating traditional sampling with innovative genetic tools, this collaboration is helping refine strategies for scaling up oyster reef restoration and strengthening the ecological resilience of New York Harbor. 8. Advanced International Collaboration in Aquatic Science and River Restoration: [gallery link="none" size="medium" ids="17275,17279,18151"] This year, Princeton Hydro shared expertise on the global stage and celebrated major milestones in international river restoration. Senior Technical Director of Ecological Services Dr. Fred Lubnow traveled to Lisbon, Portugal, for the 17th International Symposium on Aquatic Plants, where he presented on managing submerged aquatic vegetation to prevent harmful algal blooms. Director of Aquatics Michael Hartshorne spoke at the Southern African Society for Aquatic Scientists Congress in Pietermaritzburg, South Africa, an event that convened researchers, industry professionals, and government leaders to advance aquatic science through collaboration and applied research. President Geoffrey M. Goll, PE, participated in a symposium in Durban, South Africa, focused on Dam Management and Restoration of River Connectivity organized by Dam Removal South Africa and the Institute of Natural Resources. We also celebrated progress in Portugal: Dam Removal Europe published a new case study on the Perofilho Weir removal and stream restoration project in Santarém for which Geoffrey M. Goll contributed to the removal design, helping reconnect 2.5 km of stream habitat and restore fish passage. In February, we published a blog highlighting Geoffrey's ongoing collaboration in Portugal and his October 2024 visit to key restoration sites, showcasing how barrier removal is addressing river fragmentation and creating a blueprint for future efforts. 9. Unveiled 4 New Public Resources: We collaborated with the Bucks County Conservation District and Bucks County Planning Commission to launch the Lake Luxembourg Restoration StoryMap, an interactive tool that chronicles the decade-long effort to restore Lake Luxembourg’s Conservation Pool. This dynamic resource combines maps, multimedia, and storytelling to make restoration details accessible to the public. Working with Rutgers University’s Climate Change Resource Center and The Nature Conservancy, we contributed technical expertise to the New Jersey Nature-Based Solutions: Planning, Implementation, and Monitoring Reference Guide. This comprehensive guide offers science-based strategies, case studies, and funding resources to help communities implement nature-based solutions statewide. In partnership with the Borough of Harveys Lake, we developed a ArcGIS StoryMap that chronicles the community’s long-standing commitment to water quality, showcases a pilot project aimed at reducing stormwater nutrient pollution, and connects local efforts to broader Chesapeake Bay watershed health. And, for the Lower Makefield Township Environmental Advisory Council, Geoffrey M. Goll, PE, developed a Rain Gardens 101 step-by-step tutorial on designing and building rain gardens. The recorded presentation, now available to the public, provides practical tips and visuals to help homeowners improve stormwater management and support pollinator habitats. 10. Participated in 50+ Conferences, Workshops, Community Gatherings and Sponsored 30+ Events: We strengthened partnerships and advanced critical conversations through a year of dynamic engagement. From technical conferences to community events, our team shared expertise, fostered collaboration, and inspired action on climate resilience, water quality, and ecosystem restoration. Princeton Hydro was proud to participate as a sponsor, exhibitor, and session presenter at the New Jersey Association for Floodplain Management 20th Annual Conference and Exhibition - Christiana Pollack, CERP, CFM, GISP, Director of Restoration and Resilience, presented on strategies to address climate-driven impacts in Philadelphia and Clay Emerson, PhD, PE, CFM, Senior Technical Director of Engineering, led a session on establishing a stormwater utility. We participated in six SAME events, including the National Small Business Conference in Phoenix, AZ. President Geoffrey M. Goll, PE, presented to 300+ attendees during the 2025 National Dam Safety Program Technical Seminar. We gave two presentations at the Society for Ecological Restoration World Conference. Senior Manager of Aquatics Chris L. Mikolajczyk, CLM, and Senior Technical Director of Ecological Services Dr. Fred Lubnow presented at the 42nd Annual NYSFOLA Conference. As part of the Invasive Aquatic Plant Management portion of the Northeast Aquatic Plant Management Society Annual Meeting, Aquatic Ecologist Jesse Smith led a workshop on Brittle Naiad (Najas minor) Management. Aquatics Project Manager and Environmental Scientist Pat Rose presented at NJDEP’s 6th Annual Harmful Algal Bloom Summit. During the New Jersey Coastal Resilience Collaborative for its Coastal Ecological Restoration Technical Workshop, Director of Marketing & Communications, Dana Patterson Grear, presented “How to Build a Digital Communications Toolkit for Climate Action.” Locally, we celebrated community and stewardship through events like the Trenton Reel and Restore Day and Trenton River Fest. These are just a few highlights from a truly impactful year! As we look back on these achievements, we are deeply grateful for the relationships that made them possible. Your confidence in and support of our mission empowers us to innovate, restore, and protect the natural resources we all depend on. Here’s to building on this momentum in 2026 and continuing to make a positive impact together! [post_title] => A Year in Review: Top 10 Successes of 2025 [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => a-year-in-review-top-10-successes-of-2025 [to_ping] => [pinged] => [post_modified] => 2025-12-24 13:39:41 [post_modified_gmt] => 2025-12-24 13:39:41 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=18979 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 18009 [post_author] => 1 [post_date] => 2025-08-07 19:26:22 [post_date_gmt] => 2025-08-07 19:26:22 [post_content] => We're pleased to announce the release of the "New Jersey Nature-Based Solutions: Planning, Implementation, and Monitoring Reference Guide," a free resource that provides a comprehensive roadmap to incorporating nature-based solutions (NBS) into infrastructure, construction, restoration, and resilience projects across the state. Created by the Rutgers University New Jersey Climate Change Resource Center with support from The Nature Conservancy in New Jersey, the guide compiles current research, case studies, best practices, practical tools, science-based strategies, and funding resources to "inform and empower readers to implement and seek funding for NBS." Click here to view and download the guide now. Inside the Guide As the guide states, "nature-based solutions (NBS) are defined as actions to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously benefiting people and nature." (IUCN 2024) Whether you're a municipal planner, community leader, contractor, public- or private-sector professional, or an academic, new to NBS or experienced in large-scale restoration projects, the guide offers value at every level with practical instruction that spans the full project lifecycle, from planning and permitting to funding and long-term monitoring. While the content is tailored to New Jersey's diverse landscapes, the guide's insights and approaches are broadly applicable to regions with similar ecosystems, from Massachusetts to Virginia. The guide equips readers with:
As 2025 comes to a close, we’re proud to reflect on a year of innovation, collaboration, and impact. From advancing ecosystem restoration and water quality initiatives to sharing expertise on the global stage, these milestones showcase the dedication of our team and the strength of our partnerships. None of this would have been possible without the trust and support of our clients, collaborators, and community. Join us as we celebrate the Top 10 Successes of 2025:
After more than a century of standing, the Paulina Lake Dam on the Paulins Kill River in Warren County, NJ, was fully removed, marking a transformative milestone for one of New Jersey’s largest tributaries to the Delaware River. Led by The Nature Conservancy New Jersey and funded by NJDEP Division of Fish and Wildlife, this multi-phase project concluded this summer with the third and final phase that included adaptive management work and habitat enhancements to boost biodiversity. We provided engineering design and oversight throughout the effort helping restore natural river flow and improve ecological resilience. On the Farmington River in Connecticut, the Winchell-Smith Dam was fully removed after more than a decade of planning and collaboration. Spearheaded by the Farmington River Watershed Association, this project reconnects 30 miles of critical upstream habitat, improving fish passage for species like American shad, alewife, and American eel. We contributed engineering, design, and project oversight, working alongside partners including Miss Porter’s School, CTDEEP Fisheries, and RiverLogic Solutions. The removal enhances ecological health, fish passage, public safety, and recreational opportunities along one of New England’s most celebrated rivers.
We delivered incredible results for our nonprofit and government partners, securing over $3.2 million in funding to support projects that restore ecosystems, enhance habitats, improve water quality, and implement watershed-based green infrastructure and stormwater BMPs, with grants awarded through the National Fish and Wildlife Foundation’s Delaware Watershed Conservation Fund and Section 319(h) of the federal Clean Water Act, administered by NJDEP’s Watershed and Land Management Program. We assisted the Borough of Mountain Lakes in securing grant funding from the New Jersey Highlands Council to develop a comprehensive Lake and Watershed Management Plan for nine lakes within the Borough. Also noteworthy: of the 17 total 319(h) grants awarded statewide this year, we’re proud to be a partner on five, demonstrating our commitment to advancing watershed restoration and sustainability.
In partnership with Friends of Hopewell Valley Open Space, we kicked off a groundbreaking research project: “Monitoring Harmful Algal Blooms (HABs) in the Delaware River Watershed Using Drones and Spatial Analysis.” Funded by the National Fish and Wildlife Foundation through the Delaware Watershed Conservation Fund, this $1M initiative leverages drone technology, advanced data modeling, and community science to improve forecasting and management of HABs across a 73-mile stretch of the Delaware River and 23 associated waterbodies. We conceptualized and designed the project and are leading technical implementation, including field survey design, drone operations, data analysis, and volunteer training. By integrating drone-based remote sensing, on-the-water sampling, and spatial analysis, we aim to develop predictive tools for early detection and mitigation of HABs, helping protect drinking water supplies, wildlife, and local economies. This collaborative effort includes partners such as NYC College of Technology, Trenton Water Works, Mercer County Park Commission, The College of New Jersey, Aqua-PA, Philadelphia Water Department, Bucks County Conservation District, and Turner Designs. Data collection began in August will resume in Spring/Summer 2026 and culminate in 2027 with a final report.
Just this month, Princeton Hydro was honored with the Princeton Mercer Regional Chamber “Innovator of the Year” Award and President Geoffrey M. Goll, PE received the “Notable Achievement” Award from SAME New Jersey Post during their Annual Holiday Luncheon. Geoffrey also received a “Lifetime Achievement Award” from the New Jersey Highlands Coalition for his dedication to protecting and enhancing New Jersey’s environmental, cultural, and natural resources. For another year in row, Princeton Hydro was recognized as one of New Jersey’s “Top Workplaces of 2025.” In partnership with Warrington Township, our transformative ecological uplift initiative at Lion’s Pride Park won the 2025 Pennsylvania Governor’s Award for Environmental Excellence. We were selected as the recipient of the Friends of Hopewell Valley Open Space “Corporate Conservation Recognition" Award, a distinction that celebrates our long-standing dedication to advancing ecological resilience through science-based, innovative solutions. And, along with Crow Holdings, we were chosen for the United Away "Spirit of Philanthropy” Award.
In New York, we completed the Spring Creek North Ecosystem Restoration Project, revitalizing 43 acres of degraded habitat within the historic Jamaica Bay salt marsh system. The project restored a mosaic of ecosystems, including low marsh, high marsh, scrub-shrub wetland, and maritime upland, through activities like recontouring uplands to intertidal elevations, thin-layer sand placement, invasive species removal, and native plantings. This effort improves water quality, biodiversity, and wildlife habitat, contributing to the long-term health of Jamaica Bay. In the Meadowlands of New Jersey, we helped design and build the Steven R. Rothman Overlook and Preserve, a new five-acre public open space within the 587-acre Richard P. Kane Natural Area. The site offers ADA-accessible trails, sweeping views of the Meadowlands and NYC skyline, and a gateway into one of the state’s most ecologically significant landscapes along the Atlantic Flyway. We provided environmental, civil, and geotechnical engineering, landscape architecture, and construction oversight, ensuring the space honors decades of conservation work while creating opportunities for community connection and nature-based recreation.
Our team continues to shine, reaching new heights in research, professional development, and industry leadership. Senior Wildlife Biologist Michael McGraw, CSE, QAWB, ACE co-authored a study published in Agriculture, Ecosystems & Environment, a leading journal in agroecological research, and was featured on the Native Plants, Healthy Planet podcast, a Top 20 Nature Apple podcast with over 7,000 monthly listeners. Senior Director of Field Services Scott Churm became a PRO Certified EutroSORB® Specialist, and Geotechnical Engineer Matthew Pappas, CSS earned the highly respected Certified Construction Specifier credential from the Construction Specifications Institute. We also welcomed five new team members: Controller Andy Ryba; Senior Water Resources Engineer Rich Farella, PE, CFM; Staff Engineer Patricia Hurley, EIT; Marketing & Proposal Manager Amie Souza, and Aquatics Project Manager Tanya Dapkey, CE who earned her ESA Certified Ecologist credential this year. Way to go, team! Your dedication and talent continue to inspire us all.
Princeton Hydro teamed up with Billion Oyster Project, AKRF, and Monmouth University to explore how restored oyster reefs are revitalizing New York City’s waterways. The project, “Monitoring of Mobile Estuarine Organisms at Restored Oyster Reefs,” combines hands-on species surveys with cutting-edge environmental DNA (eDNA) analysis to capture a complete picture of reef biodiversity. As the field sampling lead, our team conducted monitoring at sites including Brooklyn Bridge Park, Bush Terminal Park, Flushing Bay, and Paedergat Basin. These efforts revealed a diverse array of estuarine life, from schooling fish to a surprise dogfish, and collected eDNA samples for advanced species detection. By integrating traditional sampling with innovative genetic tools, this collaboration is helping refine strategies for scaling up oyster reef restoration and strengthening the ecological resilience of New York Harbor.
This year, Princeton Hydro shared expertise on the global stage and celebrated major milestones in international river restoration. Senior Technical Director of Ecological Services Dr. Fred Lubnow traveled to Lisbon, Portugal, for the 17th International Symposium on Aquatic Plants, where he presented on managing submerged aquatic vegetation to prevent harmful algal blooms. Director of Aquatics Michael Hartshorne spoke at the Southern African Society for Aquatic Scientists Congress in Pietermaritzburg, South Africa, an event that convened researchers, industry professionals, and government leaders to advance aquatic science through collaboration and applied research. President Geoffrey M. Goll, PE, participated in a symposium in Durban, South Africa, focused on Dam Management and Restoration of River Connectivity organized by Dam Removal South Africa and the Institute of Natural Resources. We also celebrated progress in Portugal: Dam Removal Europe published a new case study on the Perofilho Weir removal and stream restoration project in Santarém for which Geoffrey M. Goll contributed to the removal design, helping reconnect 2.5 km of stream habitat and restore fish passage. In February, we published a blog highlighting Geoffrey's ongoing collaboration in Portugal and his October 2024 visit to key restoration sites, showcasing how barrier removal is addressing river fragmentation and creating a blueprint for future efforts.
We collaborated with the Bucks County Conservation District and Bucks County Planning Commission to launch the Lake Luxembourg Restoration StoryMap, an interactive tool that chronicles the decade-long effort to restore Lake Luxembourg’s Conservation Pool. This dynamic resource combines maps, multimedia, and storytelling to make restoration details accessible to the public. Working with Rutgers University’s Climate Change Resource Center and The Nature Conservancy, we contributed technical expertise to the New Jersey Nature-Based Solutions: Planning, Implementation, and Monitoring Reference Guide. This comprehensive guide offers science-based strategies, case studies, and funding resources to help communities implement nature-based solutions statewide. In partnership with the Borough of Harveys Lake, we developed a ArcGIS StoryMap that chronicles the community’s long-standing commitment to water quality, showcases a pilot project aimed at reducing stormwater nutrient pollution, and connects local efforts to broader Chesapeake Bay watershed health. And, for the Lower Makefield Township Environmental Advisory Council, Geoffrey M. Goll, PE, developed a Rain Gardens 101 step-by-step tutorial on designing and building rain gardens. The recorded presentation, now available to the public, provides practical tips and visuals to help homeowners improve stormwater management and support pollinator habitats.
We strengthened partnerships and advanced critical conversations through a year of dynamic engagement. From technical conferences to community events, our team shared expertise, fostered collaboration, and inspired action on climate resilience, water quality, and ecosystem restoration. Princeton Hydro was proud to participate as a sponsor, exhibitor, and session presenter at the New Jersey Association for Floodplain Management 20th Annual Conference and Exhibition - Christiana Pollack, CERP, CFM, GISP, Director of Restoration and Resilience, presented on strategies to address climate-driven impacts in Philadelphia and Clay Emerson, PhD, PE, CFM, Senior Technical Director of Engineering, led a session on establishing a stormwater utility. We participated in six SAME events, including the National Small Business Conference in Phoenix, AZ. President Geoffrey M. Goll, PE, presented to 300+ attendees during the 2025 National Dam Safety Program Technical Seminar. We gave two presentations at the Society for Ecological Restoration World Conference. Senior Manager of Aquatics Chris L. Mikolajczyk, CLM, and Senior Technical Director of Ecological Services Dr. Fred Lubnow presented at the 42nd Annual NYSFOLA Conference. As part of the Invasive Aquatic Plant Management portion of the Northeast Aquatic Plant Management Society Annual Meeting, Aquatic Ecologist Jesse Smith led a workshop on Brittle Naiad (Najas minor) Management. Aquatics Project Manager and Environmental Scientist Pat Rose presented at NJDEP’s 6th Annual Harmful Algal Bloom Summit. During the New Jersey Coastal Resilience Collaborative for its Coastal Ecological Restoration Technical Workshop, Director of Marketing & Communications, Dana Patterson Grear, presented “How to Build a Digital Communications Toolkit for Climate Action.” Locally, we celebrated community and stewardship through events like the Trenton Reel and Restore Day and Trenton River Fest. These are just a few highlights from a truly impactful year!
As we look back on these achievements, we are deeply grateful for the relationships that made them possible. Your confidence in and support of our mission empowers us to innovate, restore, and protect the natural resources we all depend on. Here’s to building on this momentum in 2026 and continuing to make a positive impact together!
We're pleased to announce the release of the "New Jersey Nature-Based Solutions: Planning, Implementation, and Monitoring Reference Guide," a free resource that provides a comprehensive roadmap to incorporating nature-based solutions (NBS) into infrastructure, construction, restoration, and resilience projects across the state.
Created by the Rutgers University New Jersey Climate Change Resource Center with support from The Nature Conservancy in New Jersey, the guide compiles current research, case studies, best practices, practical tools, science-based strategies, and funding resources to "inform and empower readers to implement and seek funding for NBS."
Click here to view and download the guide now.
As the guide states, "nature-based solutions (NBS) are defined as actions to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously benefiting people and nature." (IUCN 2024)
Whether you're a municipal planner, community leader, contractor, public- or private-sector professional, or an academic, new to NBS or experienced in large-scale restoration projects, the guide offers value at every level with practical instruction that spans the full project lifecycle, from planning and permitting to funding and long-term monitoring. While the content is tailored to New Jersey's diverse landscapes, the guide's insights and approaches are broadly applicable to regions with similar ecosystems, from Massachusetts to Virginia.
The guide also includes insights on how to address equity considerations and foster meaningful community engagement, helping users implement NBS that are both impactful and inclusive.
Princeton Hydro was proud to contribute technical expertise to this important effort. Our Director of Restoration & Resilience, Christiana L. Pollack, CERP, CFM, GISP, participated on the guide's steering committee, and our team provided informational resources, including content and case studies on invasive species management, wetland and floodplain enhancement, and dam and culvert removal to restore rivers and improve fish passage. These contributions along with those from many other participants, reflect the collaborative nature of the guide and the collective commitment to advancing NBS across the state.
The guide's easy-to-follow format includes four key sections:
Whether you're just beginning to conceptualize a project or deep into project implementation, this guide is an invaluable addition to your toolbox. We encourage you to explore, download, and share it widely! Click here to access the guide now.
The Watershed Institute and Princeton Hydro proudly present the inaugural Watershed Restoration Academy - Healthy Streams 101.
This two-day, entry level educational course is designed for water resources professionals (i.e., engineers, scientists, landscape architects, planners, restoration practitioners) seeking to obtain the foundational knowledge essential for advancing in the field of stream restoration.
Led by a licensed professional engineer, fluvial geomorphologist, regulatory experts, and watershed scientists, the course will delve into watershed analysis, stream processes, and site assessments through a balanced blend of classroom lectures and hands-on fieldwork.
Don't miss this opportunity to expand your knowledge and make a meaningful impact on stream restoration efforts. Register now to secure your spot.
Click here to read about the largest stream restoration project in Maryland. We worked with GV-Petro, a partnership between GreenVest and Petro Design Build Group, to restore over 7 miles (41,000 linear feet) of Tinkers Creek and its tributaries.
An extraordinary effort is underway in the Hudson River Valley—the removal of the Maiden Lane Dam. The towering 25-foot concrete structure, originally built for aesthetic purposes on a tributary to the Hudson River, has been impairing aquatic life and causing an array of negative environmental impacts since its construction in the early 1900s. Now, it is the focus of a project that promises to restore vital aquatic habitats.
Join us as we take a deeper look at the Maiden Lane Dam Removal project, an initiative that has been in the planning phase for nearly five years.
Located in the Town of Cortlandt on Furnace Brook, a tributary of the Hudson River, the Maiden Lane Dam was originally built by the former owners of McAndrews Estate. Unlike many dams throughout the country constructed with the primary goals of flood control, hydroelectric power, agricultural irrigation, or navigation of boats, the Maiden Lane Dam was built for aesthetic purposes. Yet the dam's impact extended well beyond its appearance.
The Maiden Lane Dam is the very first dam that fish and aquatic species encounter on Furnance Brook while attempting to travel up the Hudson River to reach foraging habitats and ancestral spawning grounds. The antiquated, unused dam poses a variety of risks to the wildlife restricted by the dam, people who live and recreate near the dam, and the environment surrounding the dam.
McAndrews Estate, along with the dam, was abandoned in the 1960s, and subsequently, Westchester County Parks assumed control of it. Shortly afterwards, the property was condemned.
In 2021, Princeton Hydro secured a contract with Westchester County to develop and finalize the dam removal engineering plans, secure permitting, and facilitate construction bid procurement. The project work also entailed collecting and analyzing sediment samples, conducting geomorphic assessments, and completing an in-depth hydraulic and hydrologic analysis focusing on potential flooding impacts. The collaboration with key stakeholders, including NYSDEC, Westchester County, and the Town of Cortlandt, ensured the feasibility of this ambitious dam removal endeavor.
The collaboration and careful planning set the stage for the much-anticipated removal of the Maiden Lane Dam.
The significance of this project cannot be overstated. Beyond its historical and ecological significance, the Maiden Lane Dam removal will reconnect approximately 1.5 miles of habitat for fish and other aquatic species. It represents a promising chapter in the ongoing efforts to revitalize Hudson River Valley streams and conserve the region's diverse fish and wildlife.
As we eagerly await the completion of the Maiden Lane Dam removal, the vision of restored aquatic habitats and thriving ecosystems shines brightly on the horizon. The journey of the Maiden Lane Dam Removal project is a testament to dedication, collaboration, and the unwavering commitment to the preservation of our natural environment.
Princeton Hydro team members Jake Dittes, PE and Duncan Simpson, PWS presented on Hudson Valley Dam removal during the 2023 National Stream Restoration Conference, hosted by the Resource Institute, a nonprofit organization dedicated to the restoration of America's precious waterways. The event, themed "Stream Restoration 2023: Finding Common Ground,” served as an inspiring backdrop for the broader narrative of stream restoration, showcasing the importance of projects like the Maiden Lane Dam removal in preserving our natural treasures.
The Maiden Lane Dam Removal is part of a larger effort, led by Riverkeeper, to restore migratory fish pathways and fisheries in the Hudson River Watershed.
Princeton Hydro has designed, permitted, and/or overseen the removal of 80+ small and large dams in the Northeast. To learn more about fish passage and dam removal efforts in the Hudson River Valley, click here. To learn more about our engineering services, click here.
If you've ever observed orange water in a river or stream after a dam has been removed, you may have been surprised by the strange color. This phenomenon is caused by iron oxide floc. But what exactly is iron oxide floc and how does it form?
Iron oxide, also known as rust, is a common compond found in nature. When it is dissolved in water, it takes on a reddish-brown color. Although the color can be alarming, iron oxide floc is relatively harmless and is actually a sign of the waterway returning to a more natural state.
The formation of iron oxide floc begins with the seepage of anaerobic groundwater through the embankment of a dam. The groundwater behind a dam often contains high levels of iron and is anaerobic (low in oxygen) because it is not exposed to the air and therefore does not have access to oxygen. When this anaerobic water reaches the other side of the dam and mixes with the aerobic surface water, the oxygen in the surface water reacts with the iron in the groundwater, forming iron oxide floc.
The orange color of the water is a result of the floc suspending in the water column and/or settling to the bottom of the waterway, creating a layer of orange sediment. In these situations, the iron oxide floc is only a temporary effect of the dam removal, not harmful to the environment, and will eventually be washed away by natural processes. As the waterway adjusts to its new, natural flow, the iron oxide floc will eventually disappear completely.
While the orange color may be surprising to see, it is a sign that the waterway is returning to a more natural state, leading to the water quality and habitat improvements achieved by dam removals. Removing outdated dams and restoring the natural flow of rivers has myriad benefits, including reconnecting river habitats that benefit fish and wildlife; reducing flood risk to surrounding communities; and promoting a healthier and more diverse ecosystem.
Princeton Hydro has designed, permitted, and overseen the removal of dozens of small and large dams throughout the Northeast. Click here to learn more about our dam engineering and removal services. And, if you're interested in reading about some of the dams we've removed in the Lehigh River Valley, click below:
In October 2021, the largest stream restoration in Maryland was completed. Over 7 miles (41,000 linear feet) of Tinkers Creek and its tributaries were stabilized and restored.
The project was designed by Princeton Hydro for GV-Petro, a partnership between GreenVest and Petro Design Build Group. Working with Prince George’s County Department of the Environment and coordinating with the Maryland-National Capital Parks and Planning Commission, this full-delivery project was designed to meet the County’s Watershed Implementation Plan total maximum daily load (TMDL) requirements and its National Pollutant Discharge Elimination System Municipal Separate Storm Sewer System (MS4) Discharge Permit conditions.
Today, we are thrilled to report that the once highly urbanized watershed is flourishing and teeming with life:
We used nature-based design and bioengineering techniques like riparian zone planting and live staking to prevent erosion and restore wildlife habitat.
10,985 native trees and shrubs were planted in the riparian area, and 10,910 trees were planted as live stakes along the streambank.
For more information about the project visit GreenVest's website and check out our blog:
The Aquetong Creek Restoration Project is situated within the former basin of Aquetong Lake, which was a 15- acre impoundment formed in 1870 by the construction of an earthen dam on Aquetong Creek. The cold-water limestone spring, which flows at a rate of about 2,000 gallons per minute at approximately 53ºf, is known to be the largest of its kind in the 5-county Philadelphia region, and one of the largest in the state of Pennsylvania.
In 2015, the Township of Solebury commenced the restoration of Aquetong Spring Park, first with a dam breach followed by a large stream restoration, reforestation, and invasive species removal. In September, the park was officially reopened to the public following a ribbon cutting ceremony. The event featured a blessing from the Lenni-Lenape Turtle Clan, the original inhabitants of the land.
Prior to European settlement, the Lenni-Lenape Tribe inhabited a village close to the spring and designated the spring “Aquetong”, meaning “at the spring among the bushes." After an outbreak of smallpox, however, the tribe abandoned the village. William Penn acquired Aquetong Spring in the early 1680’s as part of his peaceful treaty with Lenni-Lenape. The park land transferred hands many times before it was owned by Aquetong Township.
The dependability of the water flow made the Aquetong Creek an ideal location for mills. As of the early 1800’s, Aquetong Spring is known to have supplied enough water to turn two grist mills regularly throughout the year, and to have concurrently powered numerous mills including a paper mill, a fulling mill, two merchant mills, four sawmills, and an oil mill.
Around 1870, the 15-acre Aquetong Lake was created by constructing a dam at the east end of the property. This provided additional power for the local mills and a recreation area for the public. A fish hatchery was constructed at the base of the spring outfall, portions of which can still be viewed today. Shad, brook trout, and terrapin turtles were raised in the hatchery, which was available for public viewing at a cost of 25 cents per person.
Then, in 1993, the Pennsylvania Fish and Boat Commission acquired the property. A few years later, with the support of Bucks County Trout Unlimited, Solebury Township began negotiating to obtain ownership of the site. Around 1996, the State performed emergency repairs on the dam; a six-foot section of the outlet structure was removed in order to take pressure off the aging barrier. This lowered the level of the lake and added about 80 feet of wetlands to the western shoreline. However, it was recognized that a complete repair of the dam could cost over $1 million and might not be the best choice for the environment.
In 2009, after almost 15 years of negotiations, Solebury Township gained control of the property, with the goal of preserving this important natural resource. It purchased the lake and surrounding properties from the state and obtained a 25-year lease. The Township’s total costs were substantially reduced because it received a large credit in exchange for its commitment to repair the dam in the future, as well as funding from the Bucks County Natural Areas Program toward the purchase.
Following the purchase, the Township engaged in a five-year process of community outreach and consultation with environmental experts in which it considered alternatives for the Aquetong Lake dam. Choices included rebuilding the dam in its then-current form, creating a smaller lake with a cold-water bypass into Aquetong Creek, or breaching the dam and restoring a free-flowing stream. Ultimately, recognizing that the lake was a thermal reservoir which introduced warm water into Aquetong Creek and eventually into the streams and river, the Township decided to breach rather than restore the dam, and return the site to its natural state.
The Aquetong Restoration Project got underway in 2015, and Solebury Township breached the historic mill dam in Aquetong Spring Park to convert the former lake into a natural area with a free-flowing, cold water stream capable of supporting native brook trout.
After the dam breach, areas of active erosion were observed along the mainstem and a major tributary of Aquetong Creek. The steep, eroding banks, increased the sediment load to the Creek's sensitive aquatic habitat.
As with most dam removal projects, a degree of stewardship is necessary to enhance the establishment of desirable, beneficial vegetation. Additionally, Solebury Township wanted to control invasive species in Aquetong Spring Park and replant the project area with native species.
The Township secured funding to construct riparian buffers, implement streambank stabilization measures, establish trout habitat structures within the mainstem and its tributary, control invasive species, and implement a woodland restoration plan. The project was funded by a $250,000 grant from the PA Department of Conservation and Natural Resources, with an equal match from the Township. Additional grants for the project were provided by the PA Department of Community and Economic Development and the National Fish and Wildlife Foundation.
Solebury Township contracted Princeton Hydro to design the stabilization of the stream channel and floodplains within the former impoundment, monitor the stream and wetlands before and after implementation, and obtain the permits for the restoration of the former impoundment. Princeton Hydro team members designed the restoration of the main channel and tributary to reduce channel and bank erosion while supporting the brook trout habitat.
After gathering and reviewing the existing data for the site, Princeton Hydro conducted field investigations to inform and guide the final design including surveying cross sections and performing fluvial geomorphological assessments of the existing channel. Pebble counts were performed, cross sections were analyzed, and existing hydrological data was reviewed to inform the design. Simultaneously, an invasive species control and woodland restoration plan was developed for the park.
Data collected from the site was used to develop a geomorphically-appropriate, dynamically-stable design. The proposed channel design included excavation of impounded sediment to create stable channel dimensions, the addition of gravel, cobble, and boulder substrate where original/existing channel substrates were absent or insufficient, and the installation of large wood features to create aquatic habitat and enhance stability of channel bed and banks.
The banks and riparian corridor were vegetated with native seed, shrubs and trees to ultimately create a wooded, shaded riparian buffer. The design ultimately stabilized the streambanks with features that double as trout habitat and replanted the surrounding park with native vegetation.
The project was replanted with an incredibly diverse set of native species that included:
In addition to restoring the stream in the former impoundment, as a part of its Strategic Master Plan for Aquetong Spring Park, Solebury Township expanded its focus of the restoration project to include another 20 acres of forested land.
For this, Solebury developed a Woodland Restoration Plan which identified over 1,000 diseased forest trees, composed mostly of ash (Fraxinus sp.) and black walnut (Juglans nigra). It was the Township’s objective to remove the hazardous trees, re-establish a native woodland community, and establish an invasive species management program.
The trees removed as a part of this effort were repurposed for the stream restoration project and used for habitat features, stream stabilization measures, and park features (i.e. benches).
Princeton Hydro also provided stormwater design support for adjacent areas in Aquetong Spring Park, including multiple stormwater connections to the main tributary. After completion, Princeton Hydro provided bid assistance, developed a probable cost, drafted technical specifications, and produced a bid package to assist Aquetong Township in bringing the project to construction.
This restoration success could not have been possible without the hard work of so many dedicated project partners: Aquetong Spring Advisory Council, Bucks County Trout Unlimited, Solebury Township, Aquetong Township, Simone Collins Landscape Architects, PA Department of Conservation and Natural Resources, PA Department of Community and Economic Development, the National Fish and Wildlife Foundation, Lenni-Lenape Turtle Clan, and Princeton Hydro.
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Princeton Hydro specializes in the planning, design, permitting, implementing, and maintenance of ecological rehabilitation projects. To learn more about our watershed restoration services, click here. To learn about some of our award-winning restoration projects check out our blogs about the Pin Oak Forest Conservation Area freshwater wetland restoration project:
Just east of Washington D.C. in Prince George’s County, what will soon be the largest stream restoration in Maryland, is well underway. In this highly urbanized watershed, over 7 miles (41,000 linear feet) of Tinkers Creek and its tributaries, Meetinghouse Branch and Paynes Branch, will be stabilized and restored using nature-based design techniques.
The project was designed by Princeton Hydro for GV-Petro, a partnership between GreenVest and Petro Design Build Group. The project aims to prevent erosion and restore wildlife habitat using bioengineering techniques like riparian zone planting and live staking. 10,985 native trees and shrubs will be planted in the riparian area, and 10,910 trees will be planted as live stakes along the streambank. Recently, this project was expanded to include the stabilization and restoration of stormwater outfalls and headwater tributaries.
Working with Prince George’s County Department of the Environment and coordinating with the Maryland-National Capital Parks and Planning Commission, this full-delivery project is designed to meet the County’s Watershed Implementation Plan (WIP) total maximum daily load (TMDL) requirements and its National Pollutant Discharge Elimination System (NPDES) Municipal Separate Storm Sewer System (MS4) Discharge Permit conditions.
Prince George’s County borders the eastern portion of Washington, D.C and is the second-most populous county in Maryland. Tinkers Creek is located on a five-mile stretch of stream valley, from Old Branch Avenue to Temple Hills Road, in Clinton and Temple Hills, Maryland. The tributary system of Tinkers Creek is described as "flashy," meaning there is a quick rise in stream level due to rainfall as a result of its high proportion of directly connected urbanized impervious areas. Its streams have storm flow rates many times higher than that from the rural and forested sub-watersheds in the southeast.
This stream restoration project was identified as a priority due to the significant levels of channel incision and the severity of erosion and its impacts on surrounding neighborhoods. Additionally, the project’s proximity to the headwater reaches located on Joint Base Andrews (JBA), so the ability to improve water quality and wildlife habitat made this project a high priority. It provides an important opportunity to create a safe, sustainable, and resilient stream valley in the community.
The design for the stream, and all of the tributaries within the restoration area, will restore these channels to their naturally-stable form. During the preliminary assessment of onsite conditions, the stream and tributaries within the restoration area were classified using geomorphic assessments and hydrologic and hydraulic analysis.
Once the stream types and conditions were identified, a series of restoration approaches were designed, including floodplain creation, bank stabilization using natural materials and plantings, re-aligning straightened stream channels to have a more natural sinuosity, stormwater conveyance, and natural material grade control structures. These changes will help to reduce channel flow velocities and shear stress for flows greater than bankfull; reduce bank erosion and maintain bank stability; treat and attenuate stormwater flows; stabilize outfalls and the receiving stream channels; and stabilize vertically unstable channels.
The project area contained various subsurface utilities like sanitary sewer along the entire reach and fiber-optics and natural gas lines crossing the corridor. Once constructed, the project will improve hydraulic, geomorphic, physicochemical, and biological stream functions. It will also increase floodplain connectivity, improve bedform diversity, restore riparian buffers, and protect public subsurface utilities. In addition to water quality benefits, this project will preserve and enhance the forested floodplain and provide ecological uplift throughout the entire stream corridor.
Planning and design for Tinkers Creek Stream Restoration began in early 2018 and construction is expected to finish ahead of schedule in Spring of 2022. Princeton Hydro is providing construction oversight of all critical structures, such as grade controls, headwater step-pool grade controls, bank stabilization structures, and stormwater outfalls.
The below photos, taken during a site visit in January, showcase some of the exciting progress made by the project team thus far.
Stay tuned for more project updates!
Princeton Hydro specializes in the planning, design, permitting, implementing, and maintenance of ecological rehabilitation projects. To learn more about our watershed restoration services, click here. We have partnered with GreenVest on a number of projects, including the award-winning Pin Oak Forest Conservation Area freshwater wetland restoration project and the Mattawoman Creek Mitigation Site wetland enhancement and restoration initiative. To learn more about GreenVest, click here.
The Resource Institute hosted its 9th Annual Mid-Atlantic Stream Restoration Conference in Baltimore, Maryland, where water resource professionals, researchers, and practitioners come together for three days to share ideas and learn about stream restoration planning, assessment, design, construction, evaluation, and other topical stream issues. The conference, which was themed Building Resilient Streams in the Mid-Atlantic and Northeast regions, included presentations, discussions, exhibits, and pre-conference workshops. Princeton Hydro participated in three presentations on a variety of topics.
Below, we provide a synopsis of each presentation:
The presentation provides a detailed look at the removal of the Martin Dam in Fallston, Maryland, and how project partners were able to drastically expand the footprint of this emergency dam removal to generate enough ecological restoration benefits to adequately fund the dam removal itself.
The Martin Dam was constructed in 1965 as part of USDA’s sustainable farms pond construction initiative, which promoted aquaculture and subsistence fish production on small farms across the region as an income source for agricultural producers. Dam-related impacts included the permanent loss of spring-fed sedge wetlands, ditching of forested floodplain wetlands, pollution from stream bank entrenchment, and thermal impacts to a wild brook trout population downstream.
Overtime, the dam structure began to degrade. With each state and local agency inspection that was conducted, the dam increased in hazard category. In 2016, the Maryland Department of the Environment (MDE) was forced to list the dam as a, “public safety hazard at risk of immanent failure.” The landowner, unable to fund the dam removal, contacted GreenTrust Alliance (GTA), a regional green infrastructure nonprofit organization, for help.
By emphasizing the ecological benefits of restored wetlands and streams above and below the dam as well as the critical public safety hazard faced by residents and motorists downstream, GTA, in partnership with Princeton Hydro and GreenVest, was able to secure restoration funding for the site. The design and permitting was led by Princeton Hydro, and the dam was safely breached as part of restoration construction in January 2019.
In order to explore the use of drone or UAV technology to evaluate the effects of dam removals, the presentation showcases the Columbia Lake Dam removal, the largest dam removal in New Jersey to date.
The Columbia Lake Dam, built in 1909, was 18 feet high, 330 feet long dam, and stretched more than 1.5 miles on the Paulins Kill less than 0.25 miles upstream from its confluence with the Delaware River. As part of The Nature Conservancy’s (TNC) mission to improve the quality of the Paulins Kill, removing this “first blockage” was the cornerstone of the larger mission. Princeton Hydro served as the engineer-of-record, designing and permitting this project. Dam removal activities commenced in 2018 and were finalized in 2019. Its removal opens 10 miles of river for fish migration and improves recreation access, floodplain reconnection, habitat enhancement and higher water quality.
TNC will conduct five years of monitoring, a vitally important component of this project, to determine long-term ecological uplift, short-term positive and negative effects, and to develop data to provide information for future dam removals. And, as a result of the programmable and repeatable nature of drone flight paths, such monitoring will be able to be conducted for years and decades, producing invaluable data for research and future project design.
The presentation reviews the various parameters investigated, the results and significance of the data retrieved, and recommendations for the use of drone technology for future ecosystem restoration projects.
This presentation provides an overview on how to create 3D river models based on geomorphic input to enhance the overall accuracy and quality of a river restoration project.
In river restoration, the proposed geometry of the river channel is the key part of the design. It impacts earthwork, utility conflicts, plan set layout, and many other aspects of the project. In larger projects with reaches measuring thousands of feet and greater, manual grading is extremely time consuming and tedious; and determining the entire implication of the proposed design is difficult to achieve when simply analyzing proposed cross-sections and profiles. To increase efficiency and maintain uniformity throughout the subject reach developing a 3D-surface model of the proposed restoration reduces design time and increases quality. AutoCAD Civil 3D can be used to convert the proposed profiles and cross-sections from a geomorphic design into a 3D surface of the river corridor.
The presentation goes through the key steps that need to be taken and strategic questions that need to be asked when modeling 3D rivers in AutoCAD along with important tips and reminders.
Stay tuned for our Spring Events Spotlight to learn how you can participate in upcoming environmental events! Click here to read more about Princeton Hydro’s river restoration services.
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.
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