We’re committed to improving our ecosystems, quality of life, and communities for the better.
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Wissahickon Valley Park is one of Philadelphia’s most treasured natural resources, welcoming more than two million visitors each year. Over time, flooding, erosion, and stormwater runoff have taken an increasing toll on the park, threatening water quality, trail safety, and recreational access.
To help protect and sustain this vital landscape and community resource, Friends of the Wissahickon (FOW), in partnership with Princeton Hydro, is conducting a comprehensive resiliency and flood study along Forbidden Drive and its seven adjacent access trails. One of the most important voices in this process is yours. A public survey is now open through June 6 to gather input on flooding, erosion, and trail conditions in these targeted areas. Your feedback will play a key role in shaping the study’s priorities and recommendations.
The new Streambank Resiliency and Flood Study builds upon the 2017 Forbidden Drive Drainage System Assessment and expands its focus to address ongoing challenges such as stormwater runoff, sediment discharge, streambank instability, and interior flooding along Forbidden Drive and its adjacent trails. As part of the study, Princeton Hydro is reassessing previously identified drainage features and conducting a comprehensive site evaluation to better understand how conditions have changed over time and where new problem areas have emerged.
At the first public meeting earlier this month, community members played an active role in shaping the direction of the study. The session began with an overview of the project’s purpose, scope, and methodology, including preliminary findings on areas most vulnerable to flooding, sediment discharge, and streambank instability. Attendees also had the opportunity to ask questions and engage directly with the project team, helping to build a shared understanding of the challenges facing the park.
Following the presentation, participants took part in an interactive mapping exercise designed to gather site-specific knowledge from those who know the park best. Working in small groups around large, printed maps of the study area, attendees identified flood-prone zones, areas of active erosion, and locations where trail conditions have declined over time along Forbidden Drive and its access points. Participants marked up the maps and shared observations, stories, and ideas for potential restoration opportunities, creating a collaborative and hands-on dialogue about the park’s needs.
This exercise generated valuable, location-specific insight that is already informing the study. Participants highlighted:
In addition to identifying problem areas, attendees also shared perspectives on what makes the park special and where restoration efforts could have the greatest impact. This type of feedback is critical to ensuring the study reflects real-world conditions and community priorities. To ensure the most comprehensive understanding of conditions in the targeted areas, the project team is looking to hear from an even broader range of park users.
While engineers and scientists are conducting in-depth field investigations and comprehensive technical analyses, they do not experience the park in the same way as those who use it regularly. The firsthand perspective of park visitors is invaluable for identifying problem areas and guiding solutions and priorities that truly reflect how the park is used and experienced.
The Lower Darby Creek Area encompasses a unique blend of residential neighborhoods, commercial zones, and critical regional infrastructure, including the Philadelphia International Airport, Interstate 95, and portions of the John Heinz National Wildlife Refuge. Despite its urban setting, the area supports diverse wetlands, waterways, and wildlife habitats that play an essential role in regional flood protection, resiliency, and ecological connectivity.
Flooding and habitat loss have long challenged the Lower Darby Creek Area, particularly in the communities of Eastwick in southwest Philadelphia and Tinicum Township of Delaware County, PA. Residents in these neighborhoods experience extreme flooding during storm and high tide events, and community groups have been leading local efforts to enhance resilience and reduce flood risk. The increasing effects of climate change, such as more intense storms, sea level rise, and frequent tidal flooding, are compounding challenges.
To help address these challenges, The Nature Conservancy in Pennsylvania (TNC) and the John Heinz National Wildlife Refuge have commissioned Princeton Hydro to lead a two-year Urban Flood and Habitat Resilience Feasibility Study for the Lower Darby Creek Area. The study aims to identify and evaluate nature-based solutions that would help to convey, store, and infiltrate water to alleviate flooding, improve habitat for local wildlife species, and enhance community resilience.
Community engagement is a cornerstone of the Feasibility Study, ensuring that local voices help shape the region’s path toward long-term resilience. The project work began with a series of community meetings to learn from residents about the impacts of flooding and the changes they want to see in their neighborhoods. The outcome of this project will be a list of 6-10 nature-based solutions that have been prioritized by community members and that have been analyzed for feasibility and potential for flood reduction and ecological benefit. This information will be presented in a Project Roadmap for the co-developed pathway to achieve community and ecological resilience through project implementation. This guidance will empower partners and communities to secure funding, implement pilot projects, and advance long-term resilience goals.
Once the study is complete, Princeton Hydro will create an interactive ArcGIS StoryMap webpage that will allow users to take a deeper dive into the study's findings and interact with the data. Users will be able to visualize flood scenarios and potential restoration opportunities and learn more about specific project activities and the proposed solutions.
Earlier this year, project partners joined residents for Eastwick Community Day, a vibrant event celebrating neighborhood connections, local leadership, and climate resilience. Hosted by the City of Philadelphia’s Office of Sustainability, the event was supported by representatives from The Nature Conservancy in Pennsylvania, John Heinz National Wildlife Refuge, and Princeton Hydro, including Director of Restoration & Resilience Christiana Pollack, CERP, CFM, GISP and Director of Aquatics Mike Hartshorne.
The gathering offered residents an opportunity to meet the organizations involved in the flood study, learn about available climate resilience resources, and share their own experiences and priorities. Alongside informational displays and project updates, attendees enjoyed a picnic lunch, family activities, and hands-on learning about nature-based solutions. It was a day that captured the spirit of collaboration driving this initiative.
The Lower Darby Creek initiative builds on Princeton Hydro’s earlier Eastwick Flood Resilience Study, expanding from a neighborhood-focused analysis to a watershed-scale approach. In 2016, in partnership with the University of Pennsylvania, the John Heinz National Wildlife Refuge, Keystone Conservation Trust, Audubon Pennsylvania, and the William Penn Foundation, Princeton Hydro conducted an analysis of Eastwick, the flood impacts created by the Lower Darby Creek, and the viability of several potential flood mitigation strategies. The study sought to answer questions commonly asked by community members related to flooding conditions, with the main question being: What impact does the landfill have on area flooding? Princeton Hydro developed a 2-D hydrologic and hydraulic model to understand how varying restoration techniques, including removal of the Clearview Landfill, expansion of the existing tidal freshwater wetland, removal of bridge infrastructure, and rerouting storm flows, would alter flooding in the Eastwick neighborhood.
Findings from that study provided key data and analytical frameworks that now inform the Lower Darby Creek Area Feasibility Study. Expanding beyond the boundaries of Eastwick, the comprehensive Lower Darby Creek Area study takes a watershed-scale view, exploring how interconnected systems, including upstream hydrology, tidal influences, and habitat networks, can be managed holistically.
Resilience is not achieved in isolation; it thrives through collaboration. The success of the Lower Darby Creek Area Feasibility Study and related restoration projects depends on a network of partners committed to shared goals. By aligning expertise, resources, and local knowledge, these partnerships create a foundation for long-term climate adaptation and ecological health. To learn more about the Nature Conservancy in Pennsylvania, click here. To learn more about the City of Philadelphia Office of Sustainability Flood Resilience Strategy for Eastwick, go here. And, click here to learn more about the John Heinz National Wildlife Refuge in Tinicum.
Princeton Hydro is also collaborating with the Refuge to restore the Refuge’s Turkey Foot area. Working with Enviroscapes and Merestone Consultants, our team designed and implemented habitat enhancement and hydrologic restoration projects to improve water quality, restore native wetland vegetation, and expand habitat for fish and wildlife. If you’re interested in learning more about this project, check out our blog: Ecological Restoration in John Heinz National Wildlife Refuge.
Princeton Hydro was proud to participate in the New Jersey Association for Floodplain Management (NJAFM) 20th Annual Conference and Exhibition, held this fall in Atlantic City, NJ. Celebrating two decades of collaboration and innovation within the floodplain management community, the conference brought together more than 500 practitioners, researchers, agency staff, and industry leaders from across the Northeast.
As the region’s premier floodplain management event, the NJAFM conference serves as a hub for sharing cutting-edge tools, best practices, and real-world strategies that help communities reduce flood risk, adapt to changing climate conditions, and build long-term resilience. Over the course of two days, participants attended educational sessions, hands-on training, and networking events centered on the theme: “NJAFM at 20 Years: Celebrate the Past, Focus on the Future.”
Princeton Hydro was excited to return as a conference sponsor, exhibitor, and session presenter.
Floodplain management is a multidisciplinary practice that integrates planning, engineering, ecological science, and public policy to reduce flood risk while preserving the natural functions of riverine and coastal systems. At its core, it involves understanding how water moves across a landscape, identifying areas vulnerable to flooding, and implementing measures that protect people, infrastructure, and ecosystems.
Floodplains provide a range of essential functions. Hydrologically, they convey, store, and infiltrate water during storm events, supporting natural flood attenuation, erosion control, and groundwater recharge. Ecologically, they contribute to biodiversity by providing habitat, migration corridors, and spawning areas for fish and wildlife. From a community perspective, well-managed floodplains can offer recreational value, improve water quality, and enhance the aesthetic and economic vitality of local neighborhoods.
Modern floodplain management relies on both structural and non-structural approaches. Structural measures may include engineered solutions such as levees, floodwalls, culvert improvements, or stormwater system upgrades. Non-structural tools often involve land-use planning, flood-resilient building standards, conservation of open space, and community engagement programs that help residents understand risk and adopt best practices.
Princeton Hydro works with municipalities, state agencies, nonprofit organizations, and watershed groups to develop and implement comprehensive floodplain management strategies across the region, emphasizing strategies that balance flood risk reduction with ecological enhancement, ensuring that floodplain management supports both resilient communities and healthy, functioning watersheds.
Pictured above: before and after photos from the Floodplain Restoration and Urban Wetland Creation project in Bloomfield Township, New Jersey. By removing a little over four acres of upland historic fill in this densely developed area and converting it into 4.2 acres of a functioning floodplain wetland, the project restored valuable ecological functions, enhances wetland and riparian zone habitat, and increases flood storage capacity for urban stormwater runoff.
Our team led two workshops at the NJAFM 20th Annual Conference:
Christiana Pollack, CERP, CFM, GISP, Princeton Hydro’s Director of Restoration and Resilience, presented on strategies to address chronic flooding and climate-driven impacts in Eastwick and Tinicum Township, Philadelphia. Her talk highlighted a two-year technical assessment commissioned by The Nature Conservancy in Pennsylvania and the John Heinz National Wildlife Refuge, and led by Princeton Hydro. The project combines integrated field data collection, advanced hydrologic and hydraulic modeling, and rigorous alternatives analysis to evaluate nature-based solutions. These include wetland creation or enhancement, stream and floodplain reconnection, and stormwater management retrofits, with the ultimate goal of restoring natural hydrologic function, reducing flood risk, and strengthening habitat and community resilience. Read more about the project here.
Elizabeth Treadway of WSP USA and Dr. Clay Emerson, PhD, PE, CFM, Senior Technical Director of Engineering at Princeton Hydro, led a session on the practical, legal, and financial considerations of establishing a stormwater utility, an increasingly vital tool for sustainable infrastructure funding. Participants learned:
The session also addressed common challenges such as aging infrastructure, rapid development, and the growing frequency of severe storm events driven by climate change. Stormwater feasibility studies were highlighted as a key resource for evaluating costs and benefits before moving forward.
Managing stormwater effectively is essential for resilient infrastructure and community safety. Click here to learn about a Stormwater Utility Investigation & Feasibility Study we conducted for the Town of Hammonton, New Jersey.
Throughout the conference, our team was able to connect with planners, municipal officials, engineers, and local leaders at our exhibitor booth. These conversations offered valuable opportunities to discuss project experiences, share resources, and learn from others working to advance resilience across New Jersey.
Princeton Hydro is proud to be part of this community and remains committed to advancing science-based, equitable, and sustainable approaches to reducing flood risk. We look forward to continuing our partnership with NJAFM and supporting clients and communities in building a safer, more resilient future.
The New Jersey Department of Environmental Protection (NJDEP) recently announced $8 million in Water Quality Restoration Grants to support projects that reduce nonpoint source pollution, mitigate harmful algal blooms, restore riparian areas, and enhance watershed and climate resilience. Funded through Section 319(h) of the federal Clean Water Act and administered by the DEP's Watershed and Land Management Program, these grants were awarded to municipalities, nonprofit organizations, and academic institutions across the state.
Princeton Hydro is proud to be a partner on five of the 17 funded projects. Our contributions vary by project and encompass activities such as engineering design, water quality assessment, watershed-based planning, and technical support for implementing stormwater and habitat restoration measures. Let's take a deeper look at these collaborative efforts:
The Watershed Institute received $205K in 319(h) grant funding to develop a watershed-based plan for the Assunpink Creek watershed, located within the Raritan River Basin. This watershed spans 11 municipalities across two counties, where varied landscapes and demographics share common challenges such as localized flooding, stormwater management, and water quality degradation, highlighting the need for a coordinated, watershed-wide, science-driven approach.
The plan will evaluate pollution sources and identify large-scale restoration opportunities, including green infrastructure and riparian buffer restoration, to improve water quality and reduce flooding. It will also assess the cost, feasibility, and pollutant reduction potential of proposed measures to ensure practical implementation. Princeton Hydro supported the Institute in developing the grant proposal and planning framework, leveraging our expertise in watershed-based planning to prioritize nature-based solutions that address both water quality and climate resilience. This initiative represents a critical step toward regional collaboration, enabling upstream and downstream communities to work together on strategies that strengthen watershed health, protect public safety, and build long-term resilience.
The Lake Hopatcong Commission (LHC) was awarded $366K to retrofit an existing stormwater detention basin between King Road and Mount Arlington Boulevard in Roxbury Township. This retrofit is part of a larger Watershed Implementation Plan that Princeton Hydro developed in collaboration with LHC, which prioritizes nutrient reduction and stormwater management strategies across the Lake Hopatcong watershed. Over the past several years, LHC has actively implemented multiple elements of this plan to address harmful algal blooms (HABs) and improve water quality.
For this project, Princeton Hydro is providing engineering design and technical oversight to transform the existing basin into a green stormwater infrastructure system that slows, captures, and naturally treats runoff before it enters King Cove. The design incorporates native vegetation, invasive species management, and erosion control measures to stabilize soils and filter pollutants, reducing nutrient loading, which is one key driver of HABs. Public outreach and pre- and post-construction water quality monitoring will ensure performance tracking and measurable improvements. This basin retrofit represents a critical step in a coordinated, science-based approach to restoring ecological health and water quality in New Jersey’s largest lake.
Jefferson Township received $350K in grant funding to develop an Emerging Contaminants Management Plan for Cozy Lake, focusing on cyanotoxins and HABs. Cozy Lake is a 28-acre waterbody within a 1,152-acre sub-watershed that includes both forested (60%) and developed (29%) land. The lake is fed by the Rockaway River at its northern end and a smaller southeastern inlet, with outflow through a dam on the western edge.
The shoreline is primarily residential lawn with minimal emergent wetlands, and several inlets and rock-lined drainage ditches exhibit erosion and lack slope protection, contributing to sediment loading. Princeton Hydro provided early technical input to shape this innovative project with the creation of a comprehensive Jefferson Township Lake and Watershed Restoration and Protection Plan. As part of the plan, Princeton Hydro made recommendations for Cozy Lake, which included enhancing shoreline buffers with native vegetation and installing living shorelines at select properties to stabilize soils, filter stormwater and reduce nutrient loading, improve habitat quality, and enhance community access. These measures, combined with in-lake monitoring and proactive management strategies, will help mitigate HABs and protect ecological and public health.
Rockaway Township received $399K in grant funding to implement elements of its Watershed Implementation Plan, focusing on green infrastructure stormwater management and nutrient reduction to improve water quality. The project will retrofit the municipal complex by converting a rock-lined drainage swale into a vegetated swale with a bioretention basin, designed to filter stormwater runoff and reduce nonpoint source pollutants entering Fox’s Pond and Fox Brook.
Princeton Hydro played a key role in developing the Watershed Implementation Plan, which encompasses 11 private lakes within the Rockaway River watershed, prioritizing critical locations for intervention and designing cost-effective green infrastructure BMPs. This regional approach aligns with strategies recommended by NJDEP and the Highlands Council. The plan included a comprehensive watershed-based assessment to identify and quantify factors contributing to eutrophication, evaluate management measures, estimate costs, and establish an implementation schedule. Princeton Hydro authored the final report, which guided the Township in applying for the Section 319(h) grant and now informs the design and construction of green stormwater infrastructure that will deliver measurable water quality improvements while supporting ecological restoration goals.
Green Trust Alliance (GTA), a nationally accredited land trust and public charity dedicated to accelerating large-scale conservation, received $1.39 million in NJDEP funding to implement green infrastructure improvements at Pinelands Regional High School in Tuckerton, New Jersey. This initiative targets the Tuckerton Creek watershed, which drains into Tuckerton Creek and ultimately flows into Barnegat Bay—a critical estuary spanning 33 municipalities in Ocean County and four in Monmouth County. The retrofit will transform the school’s stormwater detention basin into a multi-functional system that mimics natural hydrology, enhances flow control, and improves water quality locally and in the larger Barnegat Bay watershed.
Working with GTA and GreenVest, Princeton Hydro is serving as the design engineer, applying nature-based engineering and ecological restoration techniques to intercept, evapotranspire, and infiltrate stormwater runoff at its source. In addition to its technical objectives, the effort includes a strong community engagement component and an educational platform for students. By bringing green infrastructure into the school environment, the initiative provides hands-on experience with water resources, stormwater management, and ecological engineering, help to build STEM skills while fostering a deeper connection to the surrounding landscape and an understanding of how natural systems work together to support environmental and community health.
Princeton Hydro also assisted several of these partners in developing successful NJDEP Section 319(h) grant applications, providing technical documentation, conceptual designs, and pollutant load reduction estimates to strengthen the proposals.
To date, the Murphy Administration has awarded more than $33M in Water Quality Restoration grants to improve the health of waterways in all corners of the state. Click here to read about all the 2025 grant funding recipients and their innovative projects.
As NJDEP Environmental Protection Commissioner Shawn M. LaTourette noted in the department's press release, “Enhancing the ecological health of our lakes, rivers, streams and coastal waters has long been a priority of the Murphy Administration. The Department of Environmental Protection is pleased to award these grants that will help our partners advance a variety of strategies to improve the health of these waterways and enhance the quality of life in our communities.”
We are proud to play a continued role in advancing that mission: helping communities implement practical, data-driven solutions that make a measurable difference for New Jersey’s waterways and the people who depend on them. Click here to learn more about our work to protect natural habitat and restore water quality throughout the New Jersey.
Rivers are the lifeblood of ecosystems, weaving through landscapes to connect habitats, sustain biodiversity, and provide vital resources to communities. Yet, rivers around the world are disrupted by outdated dams, weirs, culverts, and other blockages that fragment habitats, block fish migration, and degrade ecological health. The consequences are far-reaching, threatening not only ecosystems but also the communities that depend on healthy rivers.
Research by the European Open Rivers Programme has highlighted both the urgent need for action and the immense potential of dam removal to restore ecosystems, improve biodiversity, and revive natural river connectivity.
Since 2022, Princeton Hydro President and Principal Geoffrey M. Goll, PE, an expert in water resources engineering, has been collaborating with organizations in Portugal to advance shared goals of river restoration and ecosystem revitalization. In October 2024, Mr. Goll traveled to Portugal, where he met with the organizations driving forward the country’s ecosystem restoration efforts and visited the sites of three key projects he has, or is currently collaborating on.
This blog explores those restoration efforts, highlighting how they address the challenges of river fragmentation while establishing a blueprint for future restoration efforts.
One of the most significant examples of these collaborative restoration efforts is the groundbreaking Galaxes Weir Removal project, which set the stage for future initiatives by addressing river fragmentation on Portugal’s Odeleite River.
Galaxes Weir Removal project in Portugal's Algarve Region marked the country’s first civil removal of an obsolete river barrier to benefit migratory fish species. Associação Natureza Portugal in association with World Wildlife Fund Portugal (ANP/WWF), a non-profit NGO dedicated to the conservation of nature and the protection of the planet, reached out to Mr. Goll and Ms. Lisa Hollingsworth-Segedy of American Rivers, to undertake this pioneering effort.
Completed in March 2023, the removal of the 2-meter-high Galaxes Weir restored 7.7 kilometers of river connectivity, aiding in the preservation of critical fish species such as the Spanish minnowcarp (Anaecypris hispanica) and the critically endangered European eel (Anguilla anguilla). By improving river flow and ecological conditions, the project also bolstered economically vital fisheries, enhanced recreational opportunities, and supported local tourism, establishing a model for future restoration initiatives. Funding for the Galaxes Weir removal was provided by the European Open Rivers Programme (EORP), a grant-giving organization dedicated to restoring European rivers. The international partnership that brought Mr. Goll and Ms. Hollingsworh-Segedy into the fold was facilitated by connections made through the World Fish Migration Foundation. He and Ms. Hollingsworth-Segedy were asked to provide guidance on the de-construction of this concrete structure.
The success of the Galaxes Weir Removal project highlights the importance of both engineering knowledge and techniques, as well as community engagement. By involving local communities throughout the process, the project fostered a sense of shared responsibility and ensured that the ecological and cultural value of the river was preserved. It also underscored the benefits of dam removal as a swift and effective strategy to enhance biodiversity and promote sustainable river management.
Building on the success of the Galaxes Weir removal, the ANP/WWF team expanded its efforts to Santarém, Portugal, northeast of Lisbon, on the Perofilho Stream, a tributary of the Tejo River. The Perofilho Weir, a 2-meter-high concrete barrier, fragmented habitats and disrupted the natural flow of the stream. The National Authority for Nature and Forests Conservation (ICNF) identified the Galaxes Weir as one of the obsolete barriers to be removed to improve fish and overall biodiversity in the area and restore fluvial connectivity.
This restoration project, initiated in 2023, was led by ANP/WWF in collaboration with SOS Animal (weir owner) and the Santarém Municipal Council (local government). Mr. Goll was invited to design the removal of the concrete weir, including innovative solutions such as the use of live timber crib walls for stream bank stabilization. He also provided consultation to the onsite construction manager during the removal process and conducted a final site walkthrough following construction, offering recommendations to ensure long-term success.
The Perofilho Weir removal, completed in October 2024, restored 2.2 kilometers of the Perofilho Stream—nearly half its total length—reconnecting it with the Tejo River. This comprehensive restoration project addressed sediment management, habitat rehabilitation, and flood risk reduction, resulting in significant improvements to water quality and ecological health. Key species benefiting from these efforts include the Eurasian otter (Lutra lutra) and the Iberian painted frog (Discoglossus galganoi). Notably, it also enabled the first research into fish species inhabiting the stream.
This milestone project not only revitalized a critical aquatic ecosystem, it also established a blueprint for future river restoration efforts in Portugal and beyond.
During Mr. Goll’s visit to Portugal in October 2024, he toured the Perofilho Weir removal site alongside Maria João Costa, Water Coordinator of ANP/WWF. Together, they participated in a live video event hosted by the World Fish Migration Foundation, celebrating the project’s success. Broadcasted on the Dam Removal Europe YouTube channel, the event highlighted the restoration effort’s impact on biodiversity and river connectivity. If you missed the live broadcast, the recording is available online. Watch now:
The Oeiras River in western Algarve winds through rural landscapes, agricultural zones, and small towns before merging with the Arade River. This intermittent Mediterranean stream supports native and endangered species and serves as a habitat for some of Portugal’s most iconic mammals.
Recognizing the river’s ecological significance, the ICNF identified it as a high-priority conservation area with potential for impactful restoration. In collaboration with the company Somincor, ICNF contracted ANP/WWF to evaluate the removal of nine barriers along the river, beginning with the upstream Horta Fialho Weir.
To complete the proposed work, ANP/WWF is undertaking several activities, including feasibility assessments, local community and stakeholder engagement, and public environmental education. ANP/WWF engaged Princeton Hydro to prepare the design and specifications for the Horta Fialho Weir removal and develop concept designs for the eight (8) additional barriers.
In October 2024, Mr. Goll spent a week in the field alongside ANP/WWF, surveying the Oeiras River and its tributaries, documenting blockages and ecosystem conditions, meeting with local dam owners and community members, and gathering field measurements to inform the designs and specifications.
The removal of the Horta Fialho Weir will reconnect 2.34 kilometers of the river and set the stage for removing the eight additional barriers, which would ultimately restore 143.4 kilometers of river connectivity. This ambitious initiative is expected to significantly enhance the river’s ecological health and improve habitats for native and endangered species, including freshwater mussels (Unio tumidiformis, Anodonta anatina, Unio delphinus), and their host fish (Squalius spp.), the migratory European eel (Anguilla anguilla), the Iberian lynx (Lynx pardinus), and the Eurasian otter (Lutra lutra).
Beyond ecological benefits, the project offers a unique opportunity to raise awareness about the advantages of dam removal and the critical importance of biodiversity conservation across Portugal. The European Open Rivers Programme is funding this landmark restoration effort.
Portugal’s ecosystem restoration projects illustrate the impact of international collaboration and knowledge exchange. By removing barriers, reconnecting habitats, and revitalizing ecosystems, these efforts are paving the way for a healthier future for rivers and the communities that depend on them. Through continued partnerships and mutual support, the journey toward sustainable environmental stewardship remains hopeful and promising.
Building on the success of these initiatives, Mr. Goll and the Princeton Hydro team look forward to continuing their work in Portugal and beyond, offering technical expertise in ecosystem restoration and barrier removal to support similar efforts around the world.
This work would not be possible without the dedication of ANP/WWF, the European Open Rivers Programme, the Dam Removal Europe team, The National Authority for Nature and Forests Conservation, Herman Wanningen, and all the local landowners who were committed to the restoration of the Oeiras River. Their commitment to river restoration and biodiversity conservation serves as an inspiration, demonstrating the transformative power of collaboration and shared vision. We encourage you to click the links provided to learn more about these vital organizations.
Princeton Hydro has successfully designed, permitted, and overseen the removal of over 84 dams to date. Mr. Goll holds a B.S. in Civil Engineering from Rutgers University and a Master of Engineering Management from UW–Madison. His knowledge encompasses water resources and geotechnical engineering, including sediment management, stream and river restoration, stormwater management, green infrastructure, freshwater wetland and coastal marsh design, dam design, and dam removal. He is recognized as a distinguished leader in advancing innovative and effective solutions for river restoration.
Nestled within the New Jersey townships of Hamilton, Robbinsville, and West Windsor lies Miry Run Dam Site 21—an expansive 279-acre parcel with a rich history dating back to its acquisition by Mercer County in the late 1970s. Originally earmarked for flood mitigation and recreation, this hidden gem is on the cusp of a remarkable transformation, poised to unveil its true potential as a thriving public park.
Central to the revitalization efforts is a comprehensive Master Plan, meticulously crafted by Mercer County Park Commission in partnership with Simone Collins Landscape Architecture and Princeton Hydro. This visionary roadmap encompasses a spectrum of engineering and ecological uplift initiatives, including:
The Master Plan serves as a long-term vision for improvements to the property and will be implemented over multiple phases. In 2021, it was recognized with the Landscape Architectural Chapter Award from the New Jersey Chapter American Society of Landscape Architects, which underscores its innovative and impactful approach to landscape design.
Now, Dam Site 21’s revitalization has begun with a crucial endeavor: the dredging of its 50-acre lake. This process, spearheaded by Mercer County Park Commission in collaboration with Princeton Hydro, aims to rejuvenate the water body by removing accumulated debris, sediment, and invasive vegetation—a vital step towards restoring its ecological balance. Beyond the aesthetic and ecological improvements, dredging enhances accessibility for recreational activities that provide an opportunity to create a deeper connection between the park’s visitors and its beautiful natural landscape.
Based on the bathymetric assessment, which the Princeton Hydro team completed as part of the Master Plan, the dredging efforts are focused on three primary areas: Area 1 is located in the main body of the lake just downstream of Line Road and will generate approximately 34,000 cubic yards of dredged material; Area 2, which has approximately 4,900 cubic yards of accumulated sediment is located in the northeast cove, just north of Area 1; and Area 3, the northwestern cove, entails the removal of approximately 7,300 cubic yards of accumulated sediment.
Before the dredging work could begin, the Princeton Hydro team was responsible for providing a sediment sampling plan, sample collection and laboratory analysis, engineering design plan, preparation and submission of all NJDEP regulatory permitting materials, preparation of the technical specifications, and bid administration. Currently, our team is providing construction administration and oversight for the project.
The journey towards Dam Site 21's revival has been marked by meticulous planning, design, and community engagement spanning several years. With the commencement of dredging operations, the project's vision is gradually materializing—a testament to the dedication of all stakeholders involved. As the first phase unfolds, anticipation mounts for the realization of a vibrant, inclusive public space that honors both nature and community.
As Dam Site 21 undergoes its metamorphosis, it symbolizes not just a physical restoration, but a renewal of collective vision and commitment. Ultimately, Dam Site 21 isn't just a park—it's a testament to the enduring legacy of conservation, community, and the transformative power of restoration.
The significance of Dam Site 21's transformation extends far beyond its recreational appeal. It embodies a commitment to environmental stewardship, with measures aimed at bolstering flood resilience, improving water quality, and nurturing diverse wildlife habitats. By blending conservation with recreation, the project strikes an important balance between creating access for community members to enjoy the space and ecological preservation that puts native plants, critical habitat, and wildlife at the forefront.
To learn more about the restoration initiative and view the Final Master Plan, visit the Mercer County Park Commission’s website. Click here to learn about another one of Princeton Hydro’s recent restoration efforts. And, stay tuned here for more Mercer County Park Commission project updates!
When New Jersey Manufacturers Insurance Group (NJM) developed their new Regional Operations Facility, a 55-acre corporate campus in Hammonton, New Jersey, they approached the construction with one major goal at the forefront: stormwater management.
Fundamental to that goal was designing a green infrastructure stormwater management system capable of containing on site nearly all the stormwater runoff generated by storm events up to and including a 100-year frequency, 24-hour duration storm.
The group hired Princeton Hydro, recognized as a leader in innovative, cost-effective, and environmentally sound stormwater management, to develop a concept plan that could be built within the context of proper stormwater management and meet the stringent requirements of the NJ Pinelands Comprehensive Management Plan.
To accomplish the ambitious stormwater management goals, the project team designed and implemented an integrated stormwater management system that combined traditional and green infrastructure components, and consisted of bioinfiltration basins, parking lot islands, a wetland basin, and a bioretention island. These features were designed to promote the interception, evapotranspiration, and infiltration of stormwater runoff at its source.
Emphasis was given to green infrastructure BMPs specifically capable of treating and infiltrating large volumes of runoff. Thus, all of the infiltration areas were designed using a soil amendment process where the underlying soils were excavated and amended with organic material to improve the underlying recharge capabilities of the soils. To complement the BMPs, the team designed and installed 120,000 gallon below-grade rainwater capture and reuse system. The system captures roof runoff to be used for on-site irrigation, which not only reduces stormwater volume but also decreases the facility’s water usage.
The project is one of the first projects in New Jersey built to infiltrate nearly 100% of the on-site runoff and uses site-design-based stormwater capacity to determine allowable impervious cover.
Before construction began, the team implemented a comprehensive study, which began with a detailed analysis of the site’s soils, with particular attention given to physical properties of the soil and the depth to seasonal high water (groundwater). During construction, Princeton Hydro provided monitoring services for all earthwork activities. Our team was on site full-time during critical activities to ensure that the project was built in accordance with the intent of the original design and ensure the maintenance of the project schedule. The team also provided environmental and geotechnical design and engineering services throughout the corporate campus construction, including the analysis of subsurface structures shop drawings and providing consultation support to the general contractor.
For the project, we partnered with Burgis Associates, Inc. who created site designs, provided landscape architectural and professional planning services, and helped to obtain agency approvals. The landscape program sought to establish native plant communities that filter runoff, provide an aesthetically pleasing visual, reduce invasive species, create habitat for pollinators and other critical species, and require limited maintenance to stay healthy and flourishing.
Post construction, the Princeton Hydro team led the preparation of the scope of services, budget, and proposal for the Stormwater Basin Maintenance, which included mowing and clearing the vegetation in nine infiltration basins. The basins were inspected monthly for functionality and for the presence of invasive plants. And, we are happy to report that the basins are all working properly and invasive plants have been eradicated.
At Princeton Hydro, we are experts in stormwater management; we recognize the numerous benefits of green infrastructure; and we’ve been incorporating green infrastructure into our engineering designs since before the term was regularly used in the stormwater lexicon. Click below to read about a Stormwater Treatment Train we designed and implemented in Thompson Park, a 675-acre recreation area in Middlesex County, New Jersey.
The New Jersey Department of Environmental Protection (NJDEP) launched a Youth Inclusion Initiative to help the State of New Jersey develop the next generation of environmental protection, conservation and stewardship leaders while also providing an avenue for young adults from open space-constrained communities to engage with nature as they provide valuable stewardship services to the public through jobs at NJDEP.
This year, the youth inclusion program is partnering with Groundwork Elizabeth, Rutgers University Camden, and Newark’s Ironbound Community Corporation to create a workforce development curriculum for people ages 17 to 24. Groundwork Elizabeth sent 12 participants to this year’s program, and Rutgers Camden and the Ironbound Community Corporation each sent 10.
The curriculum provides career education in the environmental protection field and helps the young participants develop the skills necessary to pursue those career paths in New Jersey. Participants learn through classroom instruction and by working across sectors regulated by the NJDEP, including water resources, air quality, energy and sustainability, public lands management, and wildlife.
Susan Lockwood of NJDEP’s Division of Land Resource Protection’s Mitigation Unit reached out to Princeton Hydro to showcase ecosystem restoration and mitigation efforts across the state as well as discuss the variety of career roles that make these projects possible. Our portion of the curriculum entailed each group of students visiting two sites to learn about the benefits of restoring a landscape with native vegetation. Our discussion explored different fields of work related to urban environmental restoration and water resource protection and the job responsibilities of environmental scientists, water resource engineers, geologists, ecologists, pesticide applicators, and regulatory compliance specialists.
After a quick stop at NJDEP’s office in Trenton to learn about NJ invasive species, all three groups popped over to the Tulpehaking Nature Center in Mercer County’s John A. Roebling Park to see the restoration site in the Abbott Marshlands. The 3,000-acre Abbott Marshlands is the northernmost freshwater tidal marsh on the Delaware River and contains valuable habitat for many rare species like River Otter, American Eel, Bald Eagle, and various species of wading birds. Unfortunately, the area has experienced a significant amount of loss and degradation, partially due to the introduction of the invasive Common Reed (Phragmites australis). For Mercer County Park Commission, Princeton Hydro implemented a restoration plan to remove Common Reed and expose the native seed bank in 40-acres of the marsh to increase biodiversity, improve recreational opportunities, and enhance visitor experience. Students learned how to tell the difference between the invasive Common Reed vs. native Wild Rice (Zizania palustris L.). They utilized tools of the trade like field guides and binoculars to identify flora and fauna in the marsh. Learn more about this project.
After visiting the Roebling site, students from Camden traveled down to Evesham Township in Burlington County to visit the Mullica River Wetland Mitigation Site. For this project, Princeton Hydro worked with GreenVest, LLC to restore a highly degraded 34-acre parcel of land which was previously used for cranberry cultivation. Through the implementation of restoration activities focused on removing the site’s agricultural infrastructure, Princeton Hydro and GreenVest were able to restore a natural wetland system on the site and over 1,600 linear feet of stream, providing forested, scrub-shrub, and emergent wetlands, forested uplands, headwater stream and riparian buffer, and critical wildlife habitat. The project also significantly uplifted threatened and endangered species habitats including Timber Rattlesnake.
Susan Lockwood of NJDEP, Owen McEnroe of GreenVest, and Dana Patterson of Princeton Hydro, lead the group of 10 students. They learned the difference between restoration and mitigation and got to experience the remoteness of Pinelands habitat. Walking through the site, we shared how the dam and dike removal helped to restore the river back to its natural free-flowing state and the numerous resulting environmental benefits.The site was chosen for the Camden students in order to demonstrate that successful mitigation and restoration projects happen throughout the State and not far from urban centers like Camden. Learn more about this project.
After visiting the Roebling site, students from Newark and Elizabeth trekked up to Essex County to visit an urban wetland creation project now known as Lion Gate Park. The once densely developed, abandoned Scientific Glass Factory in Bloomfield Township was transformed into a thriving public park with 4.2 acres of wetlands. Students heard the story of how this project came to be; decades of advocacy and litigation by community members and environmental nonprofits to stop redevelopment of the site into 148 townhomes. Bloomfield Township eventually secured the property to preserve as open space through a range of grants from NJDEP. Serving as the ecological engineer to Bloomfield Township, Princeton Hydro designed, permitted, and oversaw construction for the restoration project and is currently monitoring the site. The restoration work brought back to the land valuable ecological functions and natural floodplain connection, enhanced aquatic and wildlife habitat, and increased flood storage capacity for urban stormwater runoff. Learn more about this project.
The NJDEP Youth Inclusion Initiative began on July 5 with a week of orientation classes, and continued through August with classroom and in-field learning. The initiative culminates on August 26 with a graduation and NJDEP Career Day, during which students will have the opportunity to meet with and discuss career options with various organizations tabling at the event, including Princeton Hydro.
Click here to learn more about the NJDEP education program. If you’re interested in learning more about Princeton Hydro’s ecological restoration services, click here.
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:
Thousands of native flowering plants and grasses were planted at Thompson Park in Middlesex County, New Jersey. Once established, the native plant meadow will not only look beautiful, it will reduce stormwater runoff and increase habitat for birds, pollinators, and other critical species.
The planting was completed by community volunteers along with Eric Gehring of Kramer+Marks Architects, Middlesex County Youth Conservation Corps, Rutgers Cooperative Extension of Middlesex County, South Jersey Resource Conservation and Development Council, and Princeton Hydro Landscape Architect Cory Speroff, PLA, ASLA, CBLP.
All of the plants that were installed are native to the north-central region of New Jersey. Volunteers planted switchgrass (panicum virgatum), orange coneflower (rudbeckia fulgida), blue wild indigo (baptisia australis), partridge pea (chamaecrista fasciculata), Virginia mountain mint (pycnanhemum virginianum), and aromatic aster (symphyotrichum oblongifolium). In selecting the location for each of the plants, special consideration was given to each species' drought tolerance and sunlight and shade requirements. The selected plant species all provide important wildlife value, including providing food and shelter for migratory birds.
The planting initiative is one part of a multi-faceted Stormwater Treatment Train project recently completed in Thompson Park. The project is funded by a Water Quality Restoration 319(h) grant awarded to South Jersey Resource Conservation and Development Council by the NJDEP.
Middlesex County Office of Parks and Recreation and Office of Planning, NJDEP, South Jersey Resource Conservation and Development Council, Middlesex County Mosquito Extermination Commission, Freehold Soil Conservation District, Rutgers Cooperative Extension, Enviroscapes, and Princeton Hydro worked together to bring this project to fruition.
To learn more about the Thompson Park Zoo stormwater project, check out our recent blog:
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