We’re committed to improving our ecosystems, quality of life, and communities for the better.
Our passion and commitment to the integration of innovative science and engineering drive us to exceed on behalf of every client.
WP_Query Object ( [query] => Array ( [category_name] => landscape-architecture ) [query_vars] => Array ( [category_name] => landscape-architecture [error] => [m] => [p] => 0 [post_parent] => [subpost] => [subpost_id] => [attachment] => [attachment_id] => 0 [name] => [pagename] => [page_id] => 0 [second] => [minute] => [hour] => [day] => 0 [monthnum] => 0 [year] => 0 [w] => 0 [tag] => [cat] => 1887 [tag_id] => [author] => [author_name] => [feed] => [tb] => [paged] => 1 [meta_key] => [meta_value] => [preview] => [s] => [sentence] => [title] => [fields] => all [menu_order] => [embed] => [category__in] => Array ( [0] => 35 ) [category__not_in] => Array ( ) [category__and] => Array ( ) [post__in] => Array ( ) [post__not_in] => Array ( ) [post_name__in] => Array ( ) [tag__in] => Array ( ) [tag__not_in] => Array ( ) [tag__and] => Array ( ) [tag_slug__in] => Array ( ) [tag_slug__and] => Array ( ) [post_parent__in] => Array ( ) [post_parent__not_in] => Array ( ) [author__in] => Array ( ) [author__not_in] => Array ( ) [search_columns] => Array ( ) [ignore_sticky_posts] => [suppress_filters] => [cache_results] => 1 [update_post_term_cache] => 1 [update_menu_item_cache] => [lazy_load_term_meta] => 1 [update_post_meta_cache] => 1 [post_type] => [posts_per_page] => 10 [nopaging] => [comments_per_page] => 5 [no_found_rows] => [order] => DESC ) [tax_query] => WP_Tax_Query Object ( [queries] => Array ( [0] => Array ( [taxonomy] => category [terms] => Array ( [0] => landscape-architecture ) [field] => slug [operator] => IN [include_children] => 1 ) [1] => Array ( [taxonomy] => category [terms] => Array ( [0] => 35 ) [field] => term_id [operator] => IN [include_children] => ) ) [relation] => AND [table_aliases:protected] => Array ( [0] => ph_term_relationships [1] => tt1 ) [queried_terms] => Array ( [category] => Array ( [terms] => Array ( [0] => landscape-architecture ) [field] => slug ) ) [primary_table] => ph_posts [primary_id_column] => ID ) [meta_query] => WP_Meta_Query Object ( [queries] => Array ( ) [relation] => [meta_table] => [meta_id_column] => [primary_table] => [primary_id_column] => [table_aliases:protected] => Array ( ) [clauses:protected] => Array ( ) [has_or_relation:protected] => ) [date_query] => [queried_object] => WP_Term Object ( [term_id] => 1887 [name] => Landscape Architecture [slug] => landscape-architecture [term_group] => 0 [term_taxonomy_id] => 1887 [taxonomy] => category [description] => [parent] => 0 [count] => 13 [filter] => raw [term_order] => 0 [cat_ID] => 1887 [category_count] => 13 [category_description] => [cat_name] => Landscape Architecture [category_nicename] => landscape-architecture [category_parent] => 0 ) [queried_object_id] => 1887 [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 (1887) AND tt1.term_taxonomy_id IN (35) ) 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] => 2026-04-06 19:40:48 [post_modified_gmt] => 2026-04-06 19:40:48 [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] => 14684 [post_author] => 1 [post_date] => 2024-04-10 15:23:17 [post_date_gmt] => 2024-04-10 15:23:17 [post_content] => 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:
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.
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!
Your Full Name * Phone Number * Your Email * Organization Address Message *
By EmailBy Phone
Submit
Δ
Couldn’t find a match? Check back often as we post new positions throughout the year.
PRINCETON HYDRO
PRINCETON HYDRO