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[cat_name] => Flood Mitigation [category_nicename] => flood-mitigation [category_parent] => 0 ) [queried_object_id] => 35 [request] => SELECT SQL_CALC_FOUND_ROWS ph_posts.ID FROM ph_posts LEFT JOIN ph_term_relationships ON (ph_posts.ID = ph_term_relationships.object_id) LEFT JOIN ph_term_relationships AS tt1 ON (ph_posts.ID = tt1.object_id) WHERE 1=1 AND ( ph_term_relationships.term_taxonomy_id IN (35) AND tt1.term_taxonomy_id IN (40) ) AND ((ph_posts.post_type = 'post' AND (ph_posts.post_status = 'publish' OR ph_posts.post_status = 'acf-disabled'))) GROUP BY ph_posts.ID ORDER BY ph_posts.menu_order, ph_posts.post_date DESC LIMIT 0, 10 [posts] => Array ( [0] => WP_Post Object ( [ID] => 19515 [post_author] => 1 [post_date] => 2026-04-06 19:40:48 [post_date_gmt] => 2026-04-06 19:40:48 [post_content] => In developed watersheds, stormwater behavior is fundamentally altered by impervious surfaces and aging infrastructure, which can result in erosion, localized flooding, and nutrient pollution in surrounding waterways. These challenges rarely have simple or universal solutions, particularly in communities where natural systems, critical infrastructure, and public safety intersect within constrained landscapes. How practitioners navigate these challenges and decide when to rely on green, gray, or hybrid stormwater solutions was the focus of a recent educational session at The Watershed Institute’s 9th Annual New Jersey Watershed Conference. The session, led by Princeton Hydro Water Resources Engineer Sean Walsh, PE and Landscape Architect Jamie Feinstein, RLA, alongside the Mayor of Lambertville (NJ) Andrew Nowick, explored how context‑driven design informs effective stormwater and erosion control strategies in developed environments. Drawing from three real‑world case studies, the presenters examined how surrounding land use, physical constraints, risk tolerance, and stakeholder priorities shape decision‑making and why the most effective stormwater solutions are rarely one‑size‑fits‑all. This blog summarizes key lessons from that presentation, highlighting how site‑specific conditions ultimately determine whether green infrastructure, gray infrastructure, or a hybrid approach is the most appropriate tool for managing erosion, sediment, and flooding in settings shaped by competing land‑use and infrastructure demands. Understanding the Tradeoffs: Green vs. Gray Infrastructure Green infrastructure is designed to manage stormwater by mimicking natural hydrologic and geomorphic processes that are often altered or suppressed by development. Practices such as floodplain reconnection, step pools, riparian buffers, naturalized detention basins, and restored stream channels slow runoff, promote infiltration, and moderate sediment transport, while also improving water quality. When implemented at appropriate scales, these approaches can increase green space within built and urban environments, enhance habitat and biodiversity, and enrich the surrounding landscape by integrating stormwater management with ecological and recreational functions. However, the feasibility and performance of green infrastructure are highly dependent on site‑specific conditions, including available space, slope, and flow regimes, which are frequently constrained in urban environments. [gallery link="none" columns="2" size="full" ids="19522,19523"] Gray infrastructure, by contrast, is designed to prioritize conveyance, control, and predictability. Systems such as pipes, culverts, and engineered structures are well‑suited to managing high‑capacity flow rates, centralizing stormwater runoff, and conveying water safely through constrained environments. These approaches typically require smaller physical footprints than nature‑based alternatives and often involve lower long‑term maintenance demands. In developed settings, gray infrastructure can also provide critical structural support for roads, utilities, and other built infrastructure, offering a level of reliability and risk management that green infrastructure alone may not be able to achieve. Determining the appropriate balance between green and gray infrastructure requires a clear understanding of site‑specific constraints, risks, and performance needs, an approach illustrated in the case studies that follow. Three Case Studies, Three Different Answers To explore how context drives design decisions, we recently examined three real‑world case studies, each involving active erosion, sediment transport, and downstream impacts, and each arriving at a different solution. 1. Flooding at the Lambertville Fire Department: When Gray Is the Right Choice In Lambertville, New Jersey, stormwater runoff from Music Mountain, a steep, wooded hillside, was causing repeated flooding at the Fire Department below. What appeared at first to be a small drainage issue turned out to be a much larger challenge. During heavy rain events, uncontrolled runoff carved deep erosion gullies downslope, destabilizing trees and transporting sediment directly into city infrastructure. While green infrastructure options such as step pools were initially considered, feasibility limitations became evident. The steep slope, limited footprint, and extreme peak flows made a fully nature-based solution impractical and risky in this location. Instead, the selected design centered on gray infrastructure, including a piped stormwater system aligned with the existing flow path to minimize disturbance, along with redesigned and expanded inlet and outlet controls to safely convey peak flows and better capture surface runoff. This approach stabilized the hillside, reduced downstream sediment transport, and eliminated flooding impacts at a critical municipal facility. Given the severe spatial constraints and elevated risk associated with the site, gray infrastructure represented the most responsible and effective solution. 2. Holcombe Park Restoration: A Hybrid Solution At Holcombe Park, ongoing erosion and a disconnected floodplain were impairing stream function and contributing sediment and debris to downstream infrastructure. Unlike the Lambertville Fire Department site, where steep slopes, limited space, and public safety risks necessitated a primarily gray solution, Holcombe Park offered greater physical flexibility and a different risk profile. The site included more available space for in‑channel and floodplain interventions, while the contributing drainage system extended more than 1,000 feet beneath roadways before releasing flows downstream, adding jurisdictional and infrastructure considerations to the design process. Given these conditions, the project team pursued a hybrid strategy that leveraged the strengths of both green and gray infrastructure. Green infrastructure measures, including floodplain reconnection, step pools, and naturalized channel features, were incorporated where space allowed to slow flows, reduce erosive forces, and restore ecological function. At the same time, existing gray infrastructure continued to convey stormwater through developed areas where open‑channel solutions were infeasible. By allowing floodwaters to spread out and attenuate within the park, the project reduces peak velocities and limits the transport of debris and sediment to downstream culverts and roadways. This case study illustrates how, when site conditions permit, integrating green and gray infrastructure can address erosion and water quality concerns while protecting downstream assets and enhancing recreational space, achieving outcomes that neither approach could deliver on its own. 3. Pennsylvania Stream Restoration: When Natural Systems Provide the Best Answer The third case study shifts to a more open, rural setting on a residential and agricultural property in Pennsylvania, where channel incision and bank instability had become a growing safety and land‑use concern. Unlike the urban conditions present in the Lambertville Fire Department and Holcombe Park projects, this site offered sufficient space for stream and floodplain processes to function, making it well‑suited for a predominantly green infrastructure approach. Initially, the landowner attempted to address the erosion by installing a large‑diameter pipe to rapidly convey water through the affected area. While this strategy appeared to resolve the immediate problem on site, it ultimately transferred impacts downstream. Concentrated discharges from the pipe destabilized channel banks, accelerated erosion, and created new problems beyond the property boundary, while also violating local waterway regulations. This outcome illustrated how applying gray infrastructure to a system experiencing watershed‑scale hydrologic change can unintentionally amplify downstream risks. The final design focused on restoring natural stream function rather than accelerating conveyance. The project realigned the channel to an appropriate slope and sinuosity, reconnected the stream to its floodplain, incorporated step pools and stabilization features to dissipate energy, and added riparian plantings to strengthen bank stability and ecological resilience. Limited sections of pipe were retained only where necessary to accommodate crossings, ensuring compatibility with existing land uses without compromising system function. With adequate space, funding, and regulatory drivers in place, natural green infrastructure proved to be the most effective and resilient solution for this site. By treating water as a resource rather than a waste product, the project reduced erosion and sediment transport, improved water quality, and restored stream and floodplain processes that benefit both the landscape and downstream communities. This case study also demonstrates that successful stormwater and erosion control requires solutions that respond to both local conditions and the larger watershed system. Key Takeaways: Context Is Everything Across all three projects, the lesson is clear: green or gray decisions must be driven by site context, not preference alone. Surrounding land use, physical constraints, risk tolerance, regulatory requirements, and stakeholder priorities all shape what “success” looks like. Improperly sized or poorly applied infrastructure, whether it be green or gray, will fail. Effective stormwater management requires looking beyond the immediate problem and designing solutions that reflect the realities of the entire watershed system. A Longstanding Partnership with Lambertville Princeton Hydro’s participation alongside Mayor Andrew Nowick in leading the educational session at the 2026 NJ Watershed Conference reflects a long‑standing partnership with the City of Lambertville and the City’s active role in applying context‑driven stormwater solutions in a constrained, developed watershed. Our team has supported Lambertville’s stormwater management initiatives for many years, working collaboratively with City leadership to design projects that mitigate flooding while enhancing the natural environment. In September 2024, New Jersey Department of Environmental Protection Commissioner Shawn M. LaTourette presented the City of Lambertville with the NJDEP “Our Water’s Worth It” award. The award ceremony, held at a stormwater infrastructure improvement project site behind the Lambertville Fire Department, recognized the City’s commitment to improving stormwater management, addressing flooding, protecting local waterbodies, increasing storm resilience, and mitigating the impacts of climate change. Click here to learn more. [post_title] => Green or Gray? Stormwater Solutions in Constrained Watersheds [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => green-or-gray-stormwater-solutions-in-constrained-watersheds [to_ping] => [pinged] => [post_modified] => 2026-05-22 13:24:19 [post_modified_gmt] => 2026-05-22 13:24:19 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=19515 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 18641 [post_author] => 1 [post_date] => 2025-12-08 13:22:27 [post_date_gmt] => 2025-12-08 13:22:27 [post_content] => 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. For this feasibility study, Princeton Hydro is combining field data collection, hydrologic and hydraulic modeling, and alternatives analysis to determine the most effective nature-based solutions that benefit both nature and people. These may include wetland creation or enhancement, stream and floodplain reconnection, and stormwater management retrofits designed to restore natural hydrologic function. 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. Community Engagement in Action: Eastwick Community Day 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. Check out some highlights from the day, captured by Kim Hachadoorian, Stream Stewards Project Manager for The Nature Conservancy: [gallery columns="2" link="none" ids="17637,17638,17631,17635"] Building on the Eastwick Flood Resilience Study 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. [caption id="attachment_7896" align="aligncenter" width="751"] Princeton Hydro developed a 2-dimensional hydrologic and hydraulic model to understand how varying restoration techniques would alter flooding in the Eastwick neighborhood.[/caption] Partnerships for a Resilient Future 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. [post_title] => Building Resilience: Exploring Nature-Based Solutions in Lower Darby Creek [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => building-resilience-exploring-nature-based-solutions-in-lower-darby-creek [to_ping] => [pinged] => [post_modified] => 2025-12-10 15:03:38 [post_modified_gmt] => 2025-12-10 15:03:38 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=18641 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [2] => WP_Post Object ( [ID] => 18724 [post_author] => 1 [post_date] => 2025-11-21 18:54:17 [post_date_gmt] => 2025-11-21 18:54:17 [post_content] => 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. Understanding the Role of Floodplain Management 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. [gallery link="none" columns="2" size="large" ids="18742,18741"] 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. Technical Sessions Led by Princeton Hydro Our team led two workshops at the NJAFM 20th Annual Conference: Urban Flood and Habitat Resilience in the Lower Darby Creek Watershed 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. Are You Hesitant to Pursue a Stormwater Utility? 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:
In developed watersheds, stormwater behavior is fundamentally altered by impervious surfaces and aging infrastructure, which can result in erosion, localized flooding, and nutrient pollution in surrounding waterways. These challenges rarely have simple or universal solutions, particularly in communities where natural systems, critical infrastructure, and public safety intersect within constrained landscapes.
How practitioners navigate these challenges and decide when to rely on green, gray, or hybrid stormwater solutions was the focus of a recent educational session at The Watershed Institute’s 9th Annual New Jersey Watershed Conference. The session, led by Princeton Hydro Water Resources Engineer Sean Walsh, PE and Landscape Architect Jamie Feinstein, RLA, alongside the Mayor of Lambertville (NJ) Andrew Nowick, explored how context‑driven design informs effective stormwater and erosion control strategies in developed environments.
Drawing from three real‑world case studies, the presenters examined how surrounding land use, physical constraints, risk tolerance, and stakeholder priorities shape decision‑making and why the most effective stormwater solutions are rarely one‑size‑fits‑all. This blog summarizes key lessons from that presentation, highlighting how site‑specific conditions ultimately determine whether green infrastructure, gray infrastructure, or a hybrid approach is the most appropriate tool for managing erosion, sediment, and flooding in settings shaped by competing land‑use and infrastructure demands.
Green infrastructure is designed to manage stormwater by mimicking natural hydrologic and geomorphic processes that are often altered or suppressed by development. Practices such as floodplain reconnection, step pools, riparian buffers, naturalized detention basins, and restored stream channels slow runoff, promote infiltration, and moderate sediment transport, while also improving water quality. When implemented at appropriate scales, these approaches can increase green space within built and urban environments, enhance habitat and biodiversity, and enrich the surrounding landscape by integrating stormwater management with ecological and recreational functions. However, the feasibility and performance of green infrastructure are highly dependent on site‑specific conditions, including available space, slope, and flow regimes, which are frequently constrained in urban environments.
Gray infrastructure, by contrast, is designed to prioritize conveyance, control, and predictability. Systems such as pipes, culverts, and engineered structures are well‑suited to managing high‑capacity flow rates, centralizing stormwater runoff, and conveying water safely through constrained environments. These approaches typically require smaller physical footprints than nature‑based alternatives and often involve lower long‑term maintenance demands. In developed settings, gray infrastructure can also provide critical structural support for roads, utilities, and other built infrastructure, offering a level of reliability and risk management that green infrastructure alone may not be able to achieve.
Determining the appropriate balance between green and gray infrastructure requires a clear understanding of site‑specific constraints, risks, and performance needs, an approach illustrated in the case studies that follow.
To explore how context drives design decisions, we recently examined three real‑world case studies, each involving active erosion, sediment transport, and downstream impacts, and each arriving at a different solution.
In Lambertville, New Jersey, stormwater runoff from Music Mountain, a steep, wooded hillside, was causing repeated flooding at the Fire Department below. What appeared at first to be a small drainage issue turned out to be a much larger challenge. During heavy rain events, uncontrolled runoff carved deep erosion gullies downslope, destabilizing trees and transporting sediment directly into city infrastructure. While green infrastructure options such as step pools were initially considered, feasibility limitations became evident. The steep slope, limited footprint, and extreme peak flows made a fully nature-based solution impractical and risky in this location.
Instead, the selected design centered on gray infrastructure, including a piped stormwater system aligned with the existing flow path to minimize disturbance, along with redesigned and expanded inlet and outlet controls to safely convey peak flows and better capture surface runoff. This approach stabilized the hillside, reduced downstream sediment transport, and eliminated flooding impacts at a critical municipal facility. Given the severe spatial constraints and elevated risk associated with the site, gray infrastructure represented the most responsible and effective solution.
At Holcombe Park, ongoing erosion and a disconnected floodplain were impairing stream function and contributing sediment and debris to downstream infrastructure. Unlike the Lambertville Fire Department site, where steep slopes, limited space, and public safety risks necessitated a primarily gray solution, Holcombe Park offered greater physical flexibility and a different risk profile. The site included more available space for in‑channel and floodplain interventions, while the contributing drainage system extended more than 1,000 feet beneath roadways before releasing flows downstream, adding jurisdictional and infrastructure considerations to the design process.
Given these conditions, the project team pursued a hybrid strategy that leveraged the strengths of both green and gray infrastructure. Green infrastructure measures, including floodplain reconnection, step pools, and naturalized channel features, were incorporated where space allowed to slow flows, reduce erosive forces, and restore ecological function. At the same time, existing gray infrastructure continued to convey stormwater through developed areas where open‑channel solutions were infeasible. By allowing floodwaters to spread out and attenuate within the park, the project reduces peak velocities and limits the transport of debris and sediment to downstream culverts and roadways. This case study illustrates how, when site conditions permit, integrating green and gray infrastructure can address erosion and water quality concerns while protecting downstream assets and enhancing recreational space, achieving outcomes that neither approach could deliver on its own.
The third case study shifts to a more open, rural setting on a residential and agricultural property in Pennsylvania, where channel incision and bank instability had become a growing safety and land‑use concern. Unlike the urban conditions present in the Lambertville Fire Department and Holcombe Park projects, this site offered sufficient space for stream and floodplain processes to function, making it well‑suited for a predominantly green infrastructure approach.
Initially, the landowner attempted to address the erosion by installing a large‑diameter pipe to rapidly convey water through the affected area. While this strategy appeared to resolve the immediate problem on site, it ultimately transferred impacts downstream. Concentrated discharges from the pipe destabilized channel banks, accelerated erosion, and created new problems beyond the property boundary, while also violating local waterway regulations. This outcome illustrated how applying gray infrastructure to a system experiencing watershed‑scale hydrologic change can unintentionally amplify downstream risks.
The final design focused on restoring natural stream function rather than accelerating conveyance. The project realigned the channel to an appropriate slope and sinuosity, reconnected the stream to its floodplain, incorporated step pools and stabilization features to dissipate energy, and added riparian plantings to strengthen bank stability and ecological resilience. Limited sections of pipe were retained only where necessary to accommodate crossings, ensuring compatibility with existing land uses without compromising system function.
With adequate space, funding, and regulatory drivers in place, natural green infrastructure proved to be the most effective and resilient solution for this site. By treating water as a resource rather than a waste product, the project reduced erosion and sediment transport, improved water quality, and restored stream and floodplain processes that benefit both the landscape and downstream communities. This case study also demonstrates that successful stormwater and erosion control requires solutions that respond to both local conditions and the larger watershed system.
Across all three projects, the lesson is clear: green or gray decisions must be driven by site context, not preference alone. Surrounding land use, physical constraints, risk tolerance, regulatory requirements, and stakeholder priorities all shape what “success” looks like.
Improperly sized or poorly applied infrastructure, whether it be green or gray, will fail. Effective stormwater management requires looking beyond the immediate problem and designing solutions that reflect the realities of the entire watershed system.
Princeton Hydro’s participation alongside Mayor Andrew Nowick in leading the educational session at the 2026 NJ Watershed Conference reflects a long‑standing partnership with the City of Lambertville and the City’s active role in applying context‑driven stormwater solutions in a constrained, developed watershed. Our team has supported Lambertville’s stormwater management initiatives for many years, working collaboratively with City leadership to design projects that mitigate flooding while enhancing the natural environment.
In September 2024, New Jersey Department of Environmental Protection Commissioner Shawn M. LaTourette presented the City of Lambertville with the NJDEP “Our Water’s Worth It” award. The award ceremony, held at a stormwater infrastructure improvement project site behind the Lambertville Fire Department, recognized the City’s commitment to improving stormwater management, addressing flooding, protecting local waterbodies, increasing storm resilience, and mitigating the impacts of climate change. Click here to learn more.
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.
New Jersey Department of Environmental Protection (NJDEP) Commissioner Shawn M. LaTourette presented the City of Lambertville with the NJDEP "Our Water’s Worth It" award. The award ceremony, held at a stormwater infrastructure improvement project site behind the Lambertville Firehouse, celebrated the Lambertville's commitment to improving stormwater management, addressing flooding, protecting local waterbodies, increasing storm resilience, and mitigating the impacts of climate change.
In a press release announcing the award, Commissioner LaTourette said, “Modernization of stormwater management strategies and infrastructure is critical to mitigating flooding that is severely impacting communities across New Jersey. My DEP colleagues and I applaud Lambertville for paving the way for others to follow in managing stormwater more effectively.”
The "Our Water’s Worth It" campaign, launched by NJDEP earlier this year, aims to raise awareness about the importance of protecting New Jersey’s water resources. The campaign highlights municipalities, water systems, and others who go above and beyond in water resource management and infrastructure improvements. Lambertville’s forward-thinking approach to stormwater management, particularly in meeting permitting requirements ahead of schedule, earned the city this well-deserved recognition.
At Princeton Hydro, we are proud to support the City of Lambertville in its stormwater management initiatives. Our team has been working closely with Lambertville to design projects that not only mitigate flooding but also enhance the surrounding natural environment.
During the award ceremony, Senior Project Manager and Professional Engineer, Sean Walsh, PE, said: “We are honored to be here today alongside NJDEP and the City of Lambertville celebrating Lambertville's remarkable achievement in receiving the 'Our Water's Worth It' trophy. It's particularly meaningful that this recognition comes during Climate Week, underscoring the importance of local action in addressing global environmental challenges.”
Earlier this year, the Princeton Hydro team completed a comprehensive Stormwater Utility Feasibility Study, which provided critical insights into Lambertville’s current stormwater management capacity and forecasted future needs.
Among the ongoing projects, Princeton Hydro is evaluating solutions for capturing runoff and reducing flooding in Lambertville's Music Mountain area, a critical greenspace in the heart of the city. This steep, wooded hillside, home to popular nature trails, serves as a cherished spot for after-school exploration, dog walking, and outdoor recreation. Music Mountain also plays a critical role in the city’s stormwater management system, acting as a natural buffer to protect lower-lying areas from flash flooding caused by runoff from the residential neighborhoods above. However, storm sewer outfalls discharging into the hillside have created deep erosion gullies, and during heavy rain events, the runoff has flooded the Fire Department. In collaboration with the City and the Fire Department, Princeton Hydro is designing a comprehensive solution that includes both the installation of a piped stormwater system and enlarging the inlet at the base of the mountain to better capture surface water runoff.
Additionally, on the Closson Farm property, Princeton Hydro is designing a riparian restoration project to manage the effects of increasing storm intensity. Funded by the National Fish and Wildlife Foundation, this project will result in 4.6 acres of restored floodplain, 300 trees planted, creation of wildlife habitat, measurable sediment and nutrient reduction, reduced stormwater runoff, community engagement, and new walking paths for recreation.
“Together with Lambertville, we are taking essential steps to enhance the city’s infrastructure and safeguard the community against future flooding. Our partnership reflects a shared commitment to protecting the environment and promoting resilience,” said Princeton Hydro’s Director of Restoration & Resilience, Christiana Pollack, CFM, GISP.
By embracing innovative stormwater solutions, Lambertville is not only enhancing its infrastructure but also setting a benchmark for resilience and environmental stewardship across New Jersey. This recognition reflects the city’s commitment to proactive flood management and sustainability, serving as an inspiration for other communities.
Princeton Hydro is honored to partner with the City of Lambertville on these important efforts. We extend our heartfelt congratulations on this well-deserved recognition and are excited to continue our collaboration on future projects that will further strengthen the city's resilience and protect its vibrant neighborhoods.
To learn more about NJDEP’s "Our Water’s Worth It" campaign, watch the video below:
New Jersey’s water-related infrastructure is a complex system, constantly facing the challenges posed by stormwater runoff and working to properly manage it. Stormwater management isn’t just about handling rainfall; it’s a critical aspect of improving water quality and mitigating flood risks. In New Jersey, where urbanization and rainfall patterns intersect, managing stormwater is more than just a priority; it’s a necessity. To learn more about stormwater management solutions, check out our blog: "In the Eye of the Storm: Exploring A Stormwater Utility in New Jersey."
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!
New Jersey’s water-related infrastructure is a complex system, constantly facing the challenges posed by stormwater runoff and working to properly manage it. Stormwater management isn’t just about handling rainfall; it’s a critical aspect of preserving water quality and mitigating flooding risks. In New Jersey, where urbanization and rainfall patterns intersect, managing stormwater is more than just a priority; it’s a necessity. Enter a stormwater utility— a dedicated fee to address these stormwater management challenges.
New Jersey’s stormwater infrastructure (storm drains, sewer piping, etc.) is aging and unable to effectively handle the amount of runoff that has been flowing through the region in recent years. This is causing increased nutrient runoff and flooding in communities throughout the state. With increasing global temperatures and the proliferation of intense storm systems, this trend is likely to continue.
To address these issues, in 2019, New Jersey enacted the Clean Stormwater & Flood Reduction Law that allows municipalities, counties, groups of municipalities, and sewage and improvement authorities to establish a stormwater utility.
For many local leaders, the process to establish a utility can be complex, often depending on a number of details like the scope of the work and size of the community. In 2021, Princeton Hydro teamed up with the New Jersey League of Conservation Voters, New Jersey Future, and Flood Defense New Jersey to host a webinar explaining the purpose of a stormwater utility; how a stormwater utility works; how to decide if a stormwater utility is the right fit for a particular community; and how municipalities or counties can implement one.
In 2022, New Jersey Department of Environmental Protection (NJDEP) announced the availability of Technical Assistance for Stormwater Utility Feasibility Studies, which supports municipalities in completing a stormwater utility feasibility study. Stormwater feasibility studies can help communities weigh the costs and benefits of having a stormwater utility to determine if it's right for them. Princeton Hydro is currently conducting a feasibility study for the City of Lambertville.
Jersey Water Works is a collaborative effort of many diverse organizations and individuals who embrace the common purpose of transforming New Jersey’s water infrastructure. They bring people together to find equitable solutions focused on: Clean water and waterways; healthier, safer neighborhoods; local jobs; flood and climate resilience; and economic growth. Jersey Water Works consists of many different committees run by volunteers, including the Stormwater Utilities Subcommittee, which is part of the Asset Management and Finance Committee.
The Jersey Waterworks Stormwater Utility Subcommittee launched the “Stormwater Utility Informational Forum” comprising five one-hour-long, town-hall-style education sessions. Each session featured expert panelists who explored various aspects of creating a stormwater utility and establishing a sustainable and dedicated funding mechanism to pay for a community’s stormwater management program.
Utility leaders, government stormwater managers, municipal and county representatives, elected officials, experts and stakeholders came together to discuss the topics of stormwater financial planning and funding options; New Jersey legislation and the utility development process; stormwater rate structures and credits; stormwater utility policies; and stakeholder engagement.
Key leaders in the Stormwater Utility subcommittee who organized the information forum include Dana Patterson Grear, Director of Marketing and Communications for Princeton Hydro (co-chair); Micah Shapiro of RES (co-chair); Prabha Kumar of Black & Veatch Management Consulting LLC; and Elizabeth Treadway of WSP. The forum presenters included Prabha Kumar, Elizabeth Treadway, Dana Patterson Grear, Dave Mason of CDM Smith; Lindsey Sigmund of New Jersey Future.
Prabha Kumar and Dana Patterson Grear led the final session of the forum, which was dedicated to Stakeholder Engagement. They shared their expert recommendations and real-world experience in fostering community involvement, navigating the complexities of stakeholder engagement, and developing inclusive public meetings and dialogues related to implementing a stormwater utility feasibility study.
The presentation emphasized the significance of prioritizing stakeholder engagement early on and maintaining consistent engagement throughout the entire stormwater utility feasibility process. Prabha and Dana also provided tons of easy-to-follow, actionable tips, including:
How to structure your stakeholder groups, including the creation of a project team, a project champion and internal steering committee;
Which local community groups, municipal entities, and other external stakeholders to include in the conversation and when to include them;
Key factors in planning public workshops, like how many workshops to host, should the workshops be virtual or in-person, and how to structure the agenda for the best results; and
How to create engaging graphics, solicit feedback and educate the target audience in ways that are inclusive, informative and tailored to the unique characteristics of the community.
"Creating a stormwater utility in your community can be challenging as it is a public policymaking process. Engaging stakeholders throughout the entire process and educating the public is not just a step; it's the cornerstone to success," said Dana. "It's about embracing a diversity of voices from day one, listening to concerns and ideas, and collaboratively shaping a solution that resonates with your communities' needs."
Watch the full presentation.
The Stormwater Utility Information Forum served as a platform for sharing expertise and fostering dialogue around supporting community efforts to properly manage stormwater and protect water quality. As the conversation continues, it's crucial to leverage these insights to drive meaningful change in stormwater management initiatives across New Jersey.
The sessions were held via Zoom and the recordings of the forum sessions made available on the Jersey Water Works website. The recorded sessions serve as invaluable resources for individuals, communities, and policymakers interested in delving deeper into stormwater management.
The journey towards sustainable stormwater management is ongoing. If you or your community are interested in furthering this cause or exploring a stormwater utility, don't hesitate to reach out. The Jersey Water Works Stormwater Utility Subcommittee and Princeton Hydro welcome all voices committed to creating a more resilient and equitable water infrastructure. For more information about the Stormwater Utility Subcommittee or to get involved, please contact info@jerseywaterworks.org. Also, please explore New Jersey Future's New Jersey Stormwater Utility Resource Center which is a treasure trove of resources on this topic!
Princeton Hydro is a leader in innovative, cost-effective, and environmentally sound stormwater management systems. The preparation of stormwater management plans and design of stormwater management systems for pollutant reduction is an integral part of our projects - learn more.
On June 6, 2023, New Jersey Governor Philip Murphy announced the Administration’s upcoming adoption of the Inland Flood Protection Rule to better protect New Jersey’s communities from worsening riverine flooding and stormwater runoff. The rulemaking was filed with the Office of Administrative Law and was adopted, effective on July 17, 2023, after publication in the New Jersey Register. A courtesy copy of the rule and additional information are available here.
The Inland Flood Protection Rule updates New Jersey’s existing flood hazard and stormwater regulations by replacing outdated precipitation estimates with modern data that account for observed and projected increases in rainfall. These changes will help reduce flooding from stormwater runoff and increase the resilience of new developments located in flood-prone inland areas. Upon adoption, New Jersey will become the first state to use predictive precipitation modeling to implement rules to inform and protect future development and redevelopment from the impacts of climate change.
“The Inland Flood Protection Rule will serve as a critical component of my Administration’s comprehensive strategy to bolster our state’s resilience amid the worsening impacts of climate change,” said Governor Murphy. “As a national model for climate adaptation and mitigation, we can no longer afford to depend on 20th-century data to meet 21st-century challenges. This rule’s formation and upcoming adoption testify to our commitment to rely on the most up-to-date science and robust stakeholder engagement to inform our most crucial policy decisions.”
The Inland Flood Protection Rule establishes design elevations that are reflective of New Jersey’s changing climate and more frequent and intense rainfall, replacing standards based on outdated data and past conditions. The updated standards will apply to certain new and substantially reconstructed developments in inland riverine areas that are subject to flooding, but they do not prohibit development in these flood hazard areas.
Under the two primary components of the rule:
The updated standards in the Inland Flood Protection Rule will apply to new or reconstructed developments and not to existing developments. Pending development applications before NJDEP that are administratively complete at the time of adoption are not affected by these changes. Existing provisions of the flood hazard and stormwater rules that provide flexibility from strict compliance based on unique site-specific conditions will remain in place, along with new provisions designed to ensure that infrastructure projects already in progress can continue to move forward.
The final rule also provides clarifications for the legacy provision of the Flood Hazard Area Control Act rules at N.J.A.C. 7:13-2.1 to address projects that were wholly located outside the prior flood hazard area, and which have already received local approval under the Municipal Land Use Law. As initially proposed, this exemption from the new flood elevations would have been limited to those projects that had begun construction before the new rules were adopted. In recognition of the often-significant investments made for projects that have reached the stage of receiving municipal approval, NJDEP is retaining the existing exemption for such projects.
“New Jersey’s communities are facing unprecedented threats from the devastating impacts of extreme rainfall events, which are expected to continue to intensify in their frequency and severity,” said Commissioner of Environmental Protection Shawn M. LaTourette. “The Inland Flood Protection Rule ensures that inland, riverine areas at significant risk are better defined and that new and reconstructed assets in these areas are designed and constructed to protect New Jersey’s assets, economy and, above all, our people from the catastrophic effects of worsening floods. My DEP colleagues and I are truly grateful for Governor Murphy’s vision and leadership and for the thoughtful feedback we have received from the public and leaders in labor, business, local government, academia, and advocacy in designing this rule as part of the New Jersey Protecting Against Climate Threats (NJ PACT) initiative.”
In connection with the proposed Inland Flood Protection Rule, to aid the public to gauge flood risk and provide a visual approximation of regulatory jurisdiction on specific parcels, NJDEP has launched a flood indicator tool. While the tool does not provide a definitive demonstration of regulatory jurisdiction or calculate actual risk, it can be useful in assisting property owners or prospective property owners on potential risk and, by referencing the 500-year flood extent, approximate NJDEP’s regulatory jurisdiction and flood risk. Equipped with this information, property owners may then decide to take additional steps to determine actual risk, which is dependent on site-specific conditions.
The Watershed Institute’s Annual Conference brings together municipal representatives, engineers, environmental professionals, watershed advocates, business leaders, and community members to advance the best available information and techniques for protecting and restoring watersheds. The program consists of a keynote discussion, exhibits, poster sessions and presentations that combine science, policy, and practical applications.
This year’s conference, focused on stormwater management in New Jersey, Municipal Separate Storm Sewer System (MS4) permit requirements, regional solutions to address stormwater runoff and flooding, environmental justice, and the need for community-wide action.
Princeton Hydro, a proud sponsor of the conference, led two presentations:
This presentation, given by Princeton Hydro Senior Technical Director of Ecological Services Dr. Fred Lubnow and One Water Consulting, LLC Principal Jim Cosgrove P.E., provided a basic understanding of Total Maximum Daily Loads (TMDLs), how they’re connected to Watershed Implementation Plan (WIP) requirements, and addressed how towns can best utilize Waste Load Allocations in the development of a WIPs.
This presentation was led by three members of the Princeton Hydro team: Senior Technical Director of Engineering Dr. Clay Emerson P.E., CFM; Vice President, Founding Principal Mark Gallagher; and Senior Director of Ecological Services Dr. Fred Lubnow. Participants learned about how to develop regional, multi-municipality plans for improving water quality and reducing flooding.
Other presentation topics included, “Understanding Water Quality in New Jersey,” “Stormwater Utilities for Community Members,” and “Youth Advocacy – Engaging the Next Generation in MS4.” You can view all the presentations from the 6th Annual Conference by clicking below:
Princeton Hydro is recognized as a leader in innovative, cost-effective, and environmentally sound stormwater management green infrastructure. We've been incorporating green infrastructure into our engineering designs since before the term was regularly used in the stormwater lexicon. Click here to learn how we designed a green infrastructure stormwater management system, on a 55-acre corporate campus, that is 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:
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.
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