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The work focuses on controlling Phragmites australis (common reed), an aggressive invasive plant that can rapidly dominate wetlands, displacing native vegetation, reducing habitat diversity, and altering natural ecological processes. As part of a comprehensive management strategy that combines monitoring, treatment, and follow-up maintenance, Princeton Hydro recently assisted with a targeted seed-head removal effort designed to help limit the spread of existing Phragmites populations and support long-term wetland restoration goals. Working plant by plant, the field team manually clipped and collected Phragmites seed heads before they could fully mature and disperse. While time-intensive, this proactive management technique helps reduce the spread of viable seeds to nearby wetlands, minimizing opportunities for reinfestation and improving the effectiveness of broader control efforts. Once removed, seed heads were carefully collected and properly disposed of to prevent the establishment of new populations elsewhere. Successful invasive species management requires more than fieldwork alone. Long-term restoration depends on thoughtful planning, sound science, adaptive management, and strong partnerships committed to environmental stewardship. Princeton Hydro is proud to support NJDEP's efforts to protect and restore New Jersey's wetland ecosystems and help promote healthier, more resilient habitats. Enjoy the photos below for a behind-the-scenes look at our field crews in action at Swartswood State Park: [gallery link="none" ids="20750,20724,20757"] [gallery link="none" ids="20760,20729,20728"] Click here to learn more about our work in areas throughout the East Coast to address and properly manage Phragmites australis in order to restore natural habitats. [post_title] => Managing Invasive Phragmites at Swartswood State Park [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => managing-invasive-phragmites-at-swartswood-state-park [to_ping] => [pinged] => [post_modified] => 2026-10-07 13:29:32 [post_modified_gmt] => 2026-10-07 13:29:32 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=20705 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [1] => WP_Post Object ( [ID] => 19091 [post_author] => 1 [post_date] => 2026-09-23 02:58:01 [post_date_gmt] => 2026-09-23 02:58:01 [post_content] => At Great Swamp National Wildlife Refuge, every boardwalk, bird blind, and wetland pool tells a story of conservation in action. This winter, the Renova-Princeton Hydro Joint Venture was proud to partner with the Friends of Great Swamp on a targeted habitat restoration effort. This work focused on carefully reopening areas that were historically open water but had gradually filled in with vegetation and sediment due to natural ecological succession. By setting back that succession in strategic locations, the project supports wildlife and ecological function and restores treasured views of open water along some of the Refuge’s most visited trails. We invite you to watch the video below and explore the photos throughout this article for a preview of the transformation unfolding as well as an overview of the restoration effort and key project activities: [embed]https://youtu.be/UmMj_MEEe5A[/embed] A Refuge of Regional and National Importance Located in Morris County, New Jersey, just 26 miles west of New York City, the Great Swamp National Wildlife Refuge is a rare and expansive natural landscape set within one of the most developed regions of the country. The Refuge encompasses roughly 8,000 acres of freshwater wetlands, forests, and open water habitats. Ecologically, the Refuge plays a critical role along the Atlantic Flyway, providing essential resting, feeding, and breeding habitat for more than 240 bird species, including many migrating waterfowl that depend on intact wetlands as stopover sites during seasonal migrations along the East Coast. Many species also rely on the Refuge year‑round for shelter, nesting, and foraging. [gallery columns="4" ids="20672,20671,20670,20668"] The Refuge also plays a vital role beyond its boundaries. The Great Swamp acts as a natural sponge during heavy rains, storing and slowly releasing floodwaters that help protect surrounding communities. It also improves regional water quality by filtering sediment and nutrients before they reach downstream waterways. For people, the Refuge is an irreplaceable resource, offering quiet trails, boardwalks, educational programs, and opportunities to experience wildlife just a short drive from dense urban centers. Places like the bird blind and boardwalk trails connect visitors directly to the landscape, making habitat quality and visibility especially meaningful. Maintaining the delicate balance between natural processes and public access is at the heart of good refuge stewardship, and that balance is what this recently completed project with the Friends of Great Swamp supports. The Project at a Glance Over time, sediment accumulation and dense vegetation growth near boardwalks and the bird blind reduced open water areas that are valuable for dabbling ducks and other waterfowl; aquatic macroinvertebrates and breeding amphibians; and wildlife observation and education. [gallery ids="20691,20688,20689"] This project focused on selectively removing accumulated sediment and vegetation in three targeted areas to restore open water conditions without disturbing the broader wetland system. Because of the Refuge’s sensitivity, the work was completed using a custom, field‑driven approach, which allowed project ecologists, engineers, and construction crews to respond directly to site conditions while maintaining strict permit compliance. Key elements included:
This fall, Princeton Hydro's field team has been hard at work at Swartswood State Park, supporting ongoing invasive species management efforts led by the New Jersey Department of Environmental Protection (NJDEP). The work focuses on controlling Phragmites australis (common reed), an aggressive invasive plant that can rapidly dominate wetlands, displacing native vegetation, reducing habitat diversity, and altering natural ecological processes.
As part of a comprehensive management strategy that combines monitoring, treatment, and follow-up maintenance, Princeton Hydro recently assisted with a targeted seed-head removal effort designed to help limit the spread of existing Phragmites populations and support long-term wetland restoration goals.
Working plant by plant, the field team manually clipped and collected Phragmites seed heads before they could fully mature and disperse. While time-intensive, this proactive management technique helps reduce the spread of viable seeds to nearby wetlands, minimizing opportunities for reinfestation and improving the effectiveness of broader control efforts. Once removed, seed heads were carefully collected and properly disposed of to prevent the establishment of new populations elsewhere.
Successful invasive species management requires more than fieldwork alone. Long-term restoration depends on thoughtful planning, sound science, adaptive management, and strong partnerships committed to environmental stewardship. Princeton Hydro is proud to support NJDEP's efforts to protect and restore New Jersey's wetland ecosystems and help promote healthier, more resilient habitats.
Enjoy the photos below for a behind-the-scenes look at our field crews in action at Swartswood State Park:
At Great Swamp National Wildlife Refuge, every boardwalk, bird blind, and wetland pool tells a story of conservation in action. This winter, the Renova-Princeton Hydro Joint Venture was proud to partner with the Friends of Great Swamp on a targeted habitat restoration effort. This work focused on carefully reopening areas that were historically open water but had gradually filled in with vegetation and sediment due to natural ecological succession. By setting back that succession in strategic locations, the project supports wildlife and ecological function and restores treasured views of open water along some of the Refuge’s most visited trails.
Located in Morris County, New Jersey, just 26 miles west of New York City, the Great Swamp National Wildlife Refuge is a rare and expansive natural landscape set within one of the most developed regions of the country. The Refuge encompasses roughly 8,000 acres of freshwater wetlands, forests, and open water habitats. Ecologically, the Refuge plays a critical role along the Atlantic Flyway, providing essential resting, feeding, and breeding habitat for more than 240 bird species, including many migrating waterfowl that depend on intact wetlands as stopover sites during seasonal migrations along the East Coast. Many species also rely on the Refuge year‑round for shelter, nesting, and foraging.
The Refuge also plays a vital role beyond its boundaries. The Great Swamp acts as a natural sponge during heavy rains, storing and slowly releasing floodwaters that help protect surrounding communities. It also improves regional water quality by filtering sediment and nutrients before they reach downstream waterways.
For people, the Refuge is an irreplaceable resource, offering quiet trails, boardwalks, educational programs, and opportunities to experience wildlife just a short drive from dense urban centers. Places like the bird blind and boardwalk trails connect visitors directly to the landscape, making habitat quality and visibility especially meaningful.
Maintaining the delicate balance between natural processes and public access is at the heart of good refuge stewardship, and that balance is what this recently completed project with the Friends of Great Swamp supports.
Over time, sediment accumulation and dense vegetation growth near boardwalks and the bird blind reduced open water areas that are valuable for dabbling ducks and other waterfowl; aquatic macroinvertebrates and breeding amphibians; and wildlife observation and education.
This project focused on selectively removing accumulated sediment and vegetation in three targeted areas to restore open water conditions without disturbing the broader wetland system. Because of the Refuge’s sensitivity, the work was completed using a custom, field‑driven approach, which allowed project ecologists, engineers, and construction crews to respond directly to site conditions while maintaining strict permit compliance.
The work centered around three primary locations:
Together, these efforts improve habitat connectivity, enhance wetland function, and bring back open water views for visitors to enjoy. The project also creates opportunities for future habitat enhancements. As conditions allow, select areas may later be planted or seeded to support native aquatic and wetland species and reinforce the long‑term ecological value of the restored areas.
More than a year after opening to the public, the Steven R. Rothman Overlook and Preserve, in the heart of the Meadowlands, continues to demonstrate how ecological restoration goals and a vision for public access can be thoughtfully balanced to create a space that serves both people and wildlife.
When the 5-acre preserve officially opened in July 2025, it marked the culmination of years of conservation advocacy, planning, and collaboration. Today, visitors are welcomed by a thoughtfully designed landscape that has begun to settle into itself. Native trees and shrubs have established roots, meadow plantings have matured, and the site is functioning as the accessible gateway to the Meadowlands that it was intended to be.
Princeton Hydro provided landscape architecture, environmental, civil, and geotechnical engineering services that helped transform the site into a welcoming and accessible destination while preserving and enhancing its ecological value.
Cory Speroff, PLA, ASLA, CBLP, Princeton Hydro Landscape Architect and lead designer for the project, recently revisited the preserve and documented its progress through photos and video. As he walked along the ADA-accessible trails, birds and pollinators moved throughout the native vegetation framing the pathway. He observed a thriving landscape that's providing important habitat and connecting visitors with the natural world.
We invite you to watch the video and explore the photos below as we celebrate the preserve's continued evolution and the progress of this restoration effort.
To learn more about the project and the many partners who helped bring this vision to life, read our original project blog here.
Each year on September 4, National Wildlife Day celebrates the incredible diversity of animals that share our planet and raises awareness about the importance of protecting the habitats they depend on.
In recognition of National Wildlife Day, we're highlighting a restoration project focused on enhancing critical habitat at one of the nation's most unique conservation areas: the John Heinz National Wildlife Refuge at Tinicum, America's First Urban Refuge. And because a blog about wildlife is always better when the wildlife shows up, we're proud to share a collection of stunning photographs captured on-site by Princeton Hydro Vice President Mark Gallagher.
Established to preserve and restore the ecologically significant Tinicum Marsh, John Heinz National Wildlife Refuge, located in Philadelphia, Pennsylvania, protects approximately 1,200 acres of habitat, including the last remaining freshwater tidal marsh in Pennsylvania. The refuge encompasses a unique mosaic of habitats, including tidal and non-tidal freshwater marshes, freshwater tidal creeks, open-water impoundments, coastal plain forests, and early successional grasslands.
Home to a remarkable diversity of species, the refuge supports state-listed threatened and endangered wildlife, including American Bittern, Least Bittern, Black-crowned Night-Heron, King Rail, Great Egret, Yellow-crowned Night-Heron, and Sedge Wren, and serves as a critical link along the Atlantic Flyway, providing essential feeding, nesting, and resting habitat for migratory birds.
Despite its ecological significance, portions of the refuge have experienced habitat degradation from decades of historic disturbance, invasive species encroachment, and altered hydrology. Recognizing the opportunity to restore these valuable natural resources, Friends of Heinz Refuge partnered with Princeton Hydro and project teammates Enviroscapes and Merestone Consultants to provide engineering design, environmental compliance, engineering oversight, and construction implementation to enhance and restore aquatic, wetland, and riparian habitats and adjacent uplands within the Turkey Foot area of the Refuge.
The Turkey Foot project area is an approximately 7.5-acre site within the greater John Heinz NWR. The approach for the restoration project focused on creating approximately four acres of contiguous wetland habitat bordered by a functional riparian buffer. The design included the creation of three habitat zones: intertidal marsh, high marsh, and upland grassland, which provide foraging, breeding, nesting, and refuge opportunities for a wide variety of wildlife species. The restoration effort was specifically designed to support species of conservation concern, including the federally threatened Eastern Black Rail, which depends on high-quality marsh habitat for survival.
Project activities also included regrading existing ponds and channels to improve tidal exchange, creating conditions favorable for native marsh vegetation, increasing habitat complexity, and restoring natural ecological processes. These improvements helped reduce stagnant water conditions, improve water quality, and create a more resilient ecosystem capable of supporting wildlife over the long term.
Another critical component of the project involved removing invasive plant species and replacing them with diverse native vegetation. Native grasses, wildflowers, shrubs, and wetland plants were carefully selected to provide food sources, nesting cover, and shelter for wildlife. Species such as switchgrass, little bluestem, Virginia wild rye, asters, goldenrods, bergamot, and coastal panic grass were incorporated into the restoration to create habitat for birds, pollinators, and other native wildlife. The restoration of riparian buffers further enhanced habitat quality by reducing sediment inputs, improving water quality, moderating water temperatures, and supplying important food resources for fish, invertebrates, birds, and other wildlife.
As we celebrate National Wildlife Day, projects like this illustrate the meaningful role ecological restoration plays in safeguarding wildlife and maintaining the healthy ecosystems upon which both animals and communities depend. We hope you enjoyed these photographs as much as we enjoyed sharing them! Click here to see additional photos and learn more about the Turkey Foot Restoration at John Heinz National Wildlife Refuge.
We're pleased to announce the release of the "New Jersey Nature-Based Solutions: Planning, Implementation, and Monitoring Reference Guide," a free resource that provides a comprehensive roadmap to incorporating nature-based solutions (NBS) into infrastructure, construction, restoration, and resilience projects across the state.
Created by the Rutgers University New Jersey Climate Change Resource Center with support from The Nature Conservancy in New Jersey, the guide compiles current research, case studies, best practices, practical tools, science-based strategies, and funding resources to "inform and empower readers to implement and seek funding for NBS."
Click here to view and download the guide now.
As the guide states, "nature-based solutions (NBS) are defined as actions to protect, sustainably manage, and restore natural and modified ecosystems that address societal challenges effectively and adaptively, simultaneously benefiting people and nature." (IUCN 2024)
Whether you're a municipal planner, community leader, contractor, public- or private-sector professional, or an academic, new to NBS or experienced in large-scale restoration projects, the guide offers value at every level with practical instruction that spans the full project lifecycle, from planning and permitting to funding and long-term monitoring. While the content is tailored to New Jersey's diverse landscapes, the guide's insights and approaches are broadly applicable to regions with similar ecosystems, from Massachusetts to Virginia.
The guide also includes insights on how to address equity considerations and foster meaningful community engagement, helping users implement NBS that are both impactful and inclusive.
Princeton Hydro was proud to contribute technical expertise to this important effort. Our Director of Restoration & Resilience, Christiana L. Pollack, CERP, CFM, GISP, participated on the guide's steering committee, and our team provided informational resources, including content and case studies on invasive species management, wetland and floodplain enhancement, and dam and culvert removal to restore rivers and improve fish passage. These contributions along with those from many other participants, reflect the collaborative nature of the guide and the collective commitment to advancing NBS across the state.
The guide's easy-to-follow format includes four key sections:
Whether you're just beginning to conceptualize a project or deep into project implementation, this guide is an invaluable addition to your toolbox. We encourage you to explore, download, and share it widely! Click here to access the guide now.
The Steven R. Rothman Overlook and Preserve, a new five-acre public open space in the heart of the Meadowlands, is now open to the public.
Situated within the 587-acre Richard P. Kane Natural Area, the preserve offers an ADA-accessible gateway into one of New Jersey's most ecologically significant landscapes. Visitors can enjoy sweeping views of the Meadowlands and the New York City skyline while immersing themselves in a protected wetland ecosystem that lies along the Atlantic Flyway, a vital route for migratory birds. Owned by the Meadowlands Conservation Trust (MCT) and managed by the New Jersey Sports and Exposition Authority (NJSEA), the site supports a wide range of native and rare wildlife and plant species.
On July 10, local and state leaders gathered to officially dedicate the new preserve and celebrate the extraordinary efforts of former U.S. Congressman Steven R. Rothman, whose leadership was instrumental in preserving the region's critical wetlands. The ceremony brought together Governor Phil Murphy, Congressman Rothman, officials from Bergen County, NY/NJ Baykeeper, Hackensack Riverkeeper, MCT, NJSEA, project partners and community members. The event featured remarks, reflections and a ceremonial tree planting.
Addressing Congressman Rothman, "We are so proud and happy that this is named after you. You stood up when a lot of others would not. You took a bold stance. You believed in preserving the Meadowlands. We thank you and congratulate you," expressed Greg Remaud, CEO of NY/NJ Baykeeper, at the event.
A century ago, the New Jersey Meadowlands spanned over 21,000 acres of open space. Today, only 8,400 acres remain largely undeveloped. Speakers at the event reflected on the decades-long fight to protect this land, which was once targeted for commercial development, including plans for what would become the American Dream Mall. That 15-year preservation effort ultimately secured the future of this critical habitat.
Governor Murphy emphasized Rothman's role in that success: "Congressman Steven R. Rothman played an oversized role in protecting this incredible expanse of treasured, public open space, and he has been an ardent supporter of the Meadowlands in Congress and as a private citizen. I commend Congressman Rothman’s steadfast determination and that of the Meadowlands Conservation Trust in saving our natural resources."
Congressman Rothman also addressed the crowd, sharing his hope for the future of the site: "This overlook and preserve will now help assure that future generations of New Jerseyans and others will learn about this area's rich natural life and a history of how this space was saved from development.”
Congressman Rothman represented New Jersey’s 9th Congressional District from 1997 to 2013, serving in the U.S. House of Representatives for 16 years.
For nearly a decade, Congressman Rothman played a pivotal role in the fight to protect what remained of the Hackensack Meadowlands' undeveloped wetlands. At a time when large-scale development threatened the ecological integrity of the region, he brought national attention to the cause, becoming the first U.S. congressional candidate, and later Congressman, to publicly oppose projects like the proposed American Dream Mall. His advocacy helped relocate the development to a more suitable location and catalyzed a broader conservation movement.
Recognizing the ecological significance of the Meadowlands, Congressman Rothman secured $10 million in federal funding, along with additional state and local contributions, to support land acquisition, environmental remediation, and permanent protection of the remaining open space. He brought together key stakeholders, took a firm public stance on what must be preserved, and was instrumental in the formal rezoning of 8,400 acres as undevelopable. Widely acknowledged as the catalyst behind one of New Jersey’s most consequential land preservation efforts, Rothman received multiple regional and national honors for his leadership. The dedication of this new preserve in his name serves as a lasting tribute to his legacy.
The project was a design-build collaboration led by SumCo Eco-Contracting, with design services provided by Princeton Hydro, including environmental, civil, and geotechnical engineering; landscape architecture; and construction oversight.
The team approached the project with a deep sense of care and responsibility. “It’s been a privilege to support the vision for this park,” said Cory Speroff, PLA, ASLA, CBLP, Landscape Architect and Project Manager at Princeton Hydro. “From the beginning, we approached the design with a sense of responsibility and sensitivity, knowing how many people have worked tirelessly over the years to protect and preserve the surrounding wetlands. Our goal was to create a space that honors that legacy — a place where people can come to connect with the Meadowlands.”
The newly constructed preserve includes a range of low-impact park features that balance ecological protection with meaningful public access:
All elements were designed to be fully ADA-compliant, ensuring inclusive access for visitors of all abilities. The trail and parking surfaces were constructed using a geocellular confinement system, which promotes stormwater infiltration and supports long-term structural integrity. A timber guardrail was added along the drive and parking area to enhance safety and define boundaries.
In consideration of the site’s role as critical habitat, particularly for nocturnal and migratory species, artificial lighting was not included in the design.
Ecological restoration was a central focus of the project. The team planted 40 native trees and shrubs, installed a pollinator garden, and seeded the site with native, drought-tolerant grasses to improve habitat value and resilience. These nature-based enhancements not only support biodiversity but also help filter stormwater, stabilize soils, and prepare the landscape for a changing climate.
The preserve, located at the end of Jomike Court in Carlstadt, NJ, is now open daily from dawn to dusk. Visitors are encouraged to explore the trail, take in the sweeping New York City skyline views from the overlook, and appreciate the beauty and ecological richness of the Meadowlands.
Looking for more examples of how design and ecology can come together to benefit both people and nature? Check out our work at South Cape May Meadows Preserve in partnership with The Nature Conservancy in New Jersey. This beloved 200-acre coastal habitat, an international hotspot for birdwatching, draws more than 90,000 visitors annually. Princeton Hydro is helping to restore the preserve’s ecological integrity while improving public access, including recent efforts to remove invasive Phragmites and promote the return of native vegetation. Read more about the project here.
Invasive species can quickly establish themselves in habitats ranging from freshwater wetlands and riparian corridors to stormwater basins and tidal marshes, disrupting ecological balance and biodiversity, altering hydrology, and displacing native species.
Addressing these impacts requires a thoughtful, site-specific approach. Our team at Princeton Hydro works to design and implement targeted strategies that promote long-term ecological function. These integrated efforts aid in native habitat recovery, enhance water quality, and support compliance with regulatory frameworks.
Let’s take a closer look at how invasive species disrupt our ecosystems, why managing them is so important, and the cutting-edge tools and innovative techniques helping to eradicate invasives and restore balance to delicate ecosystems.
Invasive species are organisms introduced outside their native range that proliferate in new environments, often to the detriment of local ecosystems and biodiversity. Although some introductions happen naturally, most are caused by human activity—through commercial shipping and transport, travel and outdoor recreation, or sometimes deliberate introduction. Once established, invasive species often outcompete native species by growing more aggressively, reproducing more rapidly, and exploiting resources more efficiently. These advantages are amplified by the absence of natural predators and environmental controls that would normally regulate their populations.
This can lead to a cascade of ecological consequences:
Take common reed (Phragmites australis), for example. This fast-growing plant has overtaken many wetlands, meadows, and shorelines, forming dense stands that outcompete native vegetation. These monocultures reduce food sources that native species rely on and block the movement of wildlife between critical habitats. According to the National Invasive Species Information Center (NISIC), Phragmites was most likely introduced during the 1800s in ballast material used on ships. It was initially established along the Atlantic coast and quickly spread across the continent.
Another example of an aggressive invasive species is Eurasian watermilfoil (Myriophyllum spicatum), a submerged perennial aquatic plant that grows in lakes and ponds. Native to Europe, Asia, and North Africa, it was discovered in the eastern U.S. in the early 1900s, likely introduced and spread through the movement of watercraft. It establishes itself very quickly, grows rapidly, and spreads easily, forming dense mats at the water’s surface.
Left unmanaged, aggressive invasives like Phragmites and Eurasian watermilfoil can severely impact the stability of critical environmental systems. Effective control strategies help restore balance, preserve biodiversity, and safeguard the services ecosystems provide to humans and wildlife alike.
At Princeton Hydro, we use a multifaceted approach to invasive species control, employing mechanical, herbicidal, and biological strategies depending on the specific site conditions and project goals. One of our most effective tools is the Marsh Master® 2MX-KC-FH, a fully amphibious machine built to operate with minimal environmental disruption.
Equipped with hydraulic rotary cutting blades, a rear mounted roller/chopper attachment, and a front vegetation plow, the Marsh Master® cuts through dense vegetation like Phragmites, then chops and rolls the stalks, effectively preparing the soil for native seed germination or plug installation, making it ideal for nature preserves, canal banks, and restoration sites. Its light footprint (less than one pound per square inch) means it can traverse sensitive areas without damaging the soil or root layer.
Take a look at the Marsh Master® in the field, tackling Phragmites in tough terrain:
When paired with herbicide treatments and long-term monitoring, this approach has proven very effective in eradicating invasives, restoring wetland biodiversity, improving water quality, and creating wildlife habitat. Each site is carefully analyzed and, when required for optimal non-native plant management, a site-specific USEPA and state-registered herbicide is chosen to control the target plants while preserving the desirable, native vegetation currently populating the site. Application techniques, which are also specific to each site, include machine broadcast spraying, backpack foliar spraying, hand-wiping, basal applications, herbicide injection lances, along with various other techniques.
In partnership with GreenVest and the U.S. Army Corps of Engineers Baltimore District, Princeton Hydro contributed to a tidal marsh restoration project along the Patapsco River in Baltimore, Maryland. This initiative is part of the broader “Reimagine Middle Branch” plan, a community-driven revitalization effort to restore natural habitat and improve public access along 11 miles of Patapsco River shoreline.
At the project site near Reed Bird Island, roughly five acres of marsh had been overtaken by dense stands of Phragmites. The goal was to restore hydrologic connections to the Patapsco River and convert the monoculture into a thriving mosaic of native marsh vegetation. Our team used the Marsh Master® to mow and manage the Phragmites, followed by mechanical grading and sediment redistribution to create high and low marsh zones. The restoration plan included planting 5+ acres with a combination of native species and incorporating habitat features like woody debris and unplanted cobblestone patches to facilitate fish passage.
This project demonstrates how targeted invasive species control can support large-scale ecosystem restoration, community-led initiatives, and watershed-wide environmental goals.
Princeton Hydro has worked alongside New Jersey’s Mercer County Park Commission for over a decade to restore and protect some of the region’s most ecologically valuable landscapes. From comprehensive planning to boots-on-the-ground restoration, our efforts have focused on mitigating the spread of invasive species and promoting long-term ecological resilience.
John A. Roebling Memorial Park, part of the Abbott Marshlands, an ecologically rich freshwater tidal ecosystem that contains valuable habitat for many rare species, experienced a significant amount of loss and degradation, partially due to the introduction of Phragmites. In areas where Phragmites had overtaken native wetland communities, our team developed and executed an invasive species management plan tailored to the park’s unique hydrology and habitat types. Seasonal mowing in the winter and early spring with the Marsh Master® and targeted herbicide applications helped suppress invasive growth and enabled the rebound of native species, including Wild rice (Zizania aquatica), a culturally and ecologically significant plant.
Building on that success, we contributed to the development and implementation of the Master Plan for the Miry Run Dam Site 21, a comprehensive roadmap for ecological restoration and public access. We are advancing that vision through mitigating invasive species (primarily Phragmites), leading lake dredging, and executing a variety of habitat uplift efforts. Click here to learn more about this award-winning restoration initiative.
In 2024, Mercer County retained Princeton Hydro under an on-call contract for invasive species management across its park system, enabling our team to respond rapidly to emerging threats and support the county’s ongoing commitment to long-term ecosystem health.
At the Lower Raritan Mitigation Site in central New Jersey, Princeton Hydro has led a multi-year invasive species control effort as part of a larger wetland and stream restoration initiative. Dominated by reed canary grass (Phalaris arundinacea) and Phragmites, the site had lost most (if not all) of its native biodiversity and ecological function.
Our team used a phased approach—mechanical mowing, herbicide treatment, and active planting of native species—to gradually suppress invasives and restore a healthy plant community. Monitoring data over several growing seasons has shown a significant decrease in invasive cover and a measurable increase in native diversity. Ongoing eradication of aggressive species and the promotion of native plant diversity are steadily guiding the site toward a resilient, self-sustaining ecosystem.
Owned and managed by The Nature Conservancy in New Jersey, the South Cape May Meadows Preserve is a 200-acre freshwater wetland and coastal habitat in southern New Jersey that serves as a critical refuge for migratory birds and other native wildlife. The preserve attracts over 90,000 visitors each year and is internationally recognized as a prime birdwatching destination.
Princeton Hydro is collaborating with The Nature Conservancy on a multi-faceted effort to both improve public access and restore the site’s ecological integrity. In 2023 and 2024, our team initiated the mechanical removal of dense stands of Phragmites using the Marsh Master® to suppress monocultures and promote native plant regeneration. Future phases may include targeted herbicide treatments and additional mechanical work.
In addition to the invasive species management component, this project collaboration has led to the construction of 2,675 feet of new elevated boardwalks, a 480-square-foot viewing platform, and enhancements to existing trails. Designing and installing these features across sensitive wetland terrain required a thoughtful, low-impact approach. The result is a more welcoming, species-rich, and resilient landscape that invites people into nature while actively protecting it.
Invasive vegetation doesn’t just affect wild landscapes, it also poses challenges for stormwater infrastructure. Many municipalities struggle with invasives overtaking stormwater basins, reducing their capacity and function, which can lead to violations of Municipal Separate Storm Sewer System (MS4) permits and municipality stormwater management regulatory requirements.
Princeton Hydro designs and implements comprehensive stormwater basin maintenance programs that include invasive species management. Removing Phragmites, broadleaf cattail (Typha latifolia), and other aggressive species from stormwater infrastructure helps to restore hydrologic flow and ensures the basins perform as designed. These maintenance programs also help maintain MS4 compliance, protect downstream water quality, and reduce flooding risks—while enhancing habitat value where possible.
The fight against invasive and aggressive non-native species is ongoing, and success requires a combination of science, strategy, and stewardship. Each effort implemented and every acre reclaimed is a step toward protecting the ecosystems we all depend on.
Soil analysis is an essential part of environmental science, providing key insights into land composition, hydrology, and ecological health. In this installment of our "Field Notes" blog series, where we explore essential tools used by Princeton Hydro’s team, we take a deep dive into the Munsell Soil Color Chart—a standardized system that allows professionals to classify and communicate soil characteristics with accuracy. This tool is particularly useful in wetland delineations, where soil color helps determine whether an area meets the criteria for wetland classification.
What if the ground beneath your feet could tell a story? Soil isn’t just dirt; it’s a dynamic, living record of the landscape’s history, composition, and ability to sustain life. One of the most revealing clues in soil analysis is color, which reflects key properties such as drainage, organic matter content, and oxidation levels.
One key application of the Munsell Soil Color Chart is in wetland delineation, a process that determines whether a particular area meets the hydrologic, vegetative, and soil criteria for wetland classification. Soil scientists use an auger to extract a sample from the ground, where the first 6 to 12 inches, also known as the upper part, of the soil profile is the most important for determining whether the soils are hydric.
Hydric soils are defined as those that form under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part of the soil. The landscape of the site also plays a crucial role in hydric soil development. Factors such as hydrology, slope, landform, soil materials, and vegetation influence how these conditions emerge. These environmental factors trigger biogeochemical processes that lead to the development of distinct hydric soil indicators, including:
Once a scientist identifies a hydric soil, they refer to the Munsell Soil Color Chart to classify its matrix color and any hydric soil indicators present. This classification helps determine whether the area qualifies as a wetland under regulatory guidelines.
Before conducting a wetland delineation, Princeton Hydro Environmental Scientist Ivy Babson, PWS, first determines which United States Army Corps of Engineers (USACE) Wetland Delineation Region her site is located in—an essential step for ensuring proper classification. For a recent wetland delineation, Ivy identified her site as being within the Northcentral and Northeast Region and conducted pre-delineation research, which revealed that the area was characterized by shallow bedrock and exposed boulders.
Upon arriving at the site, Ivy observed that the wetland had formed within an old basin. The sloped basin floor supported hydrophytic vegetation, including cattails, sedges, and rushes, with visible drainage patterns and hummock-hollow microtopography indicating prolonged wet conditions.
Once Ivy selected a suitable location for a soil boring, she used a Dutch auger to extract a soil sample. The first 6 inches of the profile revealed very dark mineral soils with a high amount of decomposed organic material. Using the Munsell Soil Color Chart, she classified the sample as 10YR 2/1—a black, saturated mucky loam.
She also identified strong brown (7.5YR 4/6) redoximorphic features along plant root pore linings, indicating iron reduction due to prolonged saturation:
The next six inches of soil maintained a similar composition before transitioning at nine inches to a gray clay layer (10YR 5/1) with many yellowish-brown (10YR 5/6) redoximorphic features occurring as reduced iron soft masses, another clear indicator of prolonged saturation:
By 15 inches, Ivy hit bedrock, confirming that groundwater was perched above the rock layer, creating the saturated conditions necessary for hydric soil development.
To determine whether the site met wetland criteria, Ivy referred to the USACE’s Regional Supplement to the Wetland Delineation Manual, which provides region-specific hydric soil indicators. She identified several key indicators in her soil profile:
The combination of these four hydric soil indicators proves that the area is a wetland and is subject to conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part of the soil—a conclusion supported by the area's shallow bedrock, high water table, and saturated soil conditions.
Ivy draws a unique parallel between soil analysis and Vincent van Gogh’s Starry Night, transforming scientific observation into an artistic analogy:
"Looking at the Starry Night painting, my eyes are immediately drawn to the bright yellow stars and white moon against the dark blue night sky. In soil analysis, the dark blue sky represents the matrix of the soil, while the bright stars and moon resemble hydric soil indicators that ‘pop’ out. The streaking cypress tree in the painting? That’s like a redoximorphic concentration of manganese forming around a plant root. Just as these elements make Van Gogh’s painting unique, hydric soil indicators reveal the unique story of the land beneath our feet."
Beyond wetland delineation, soil classification is a key component of environmental restoration, conservation planning, and land management. The ability to analyze and interpret soil properties helps scientists understand long-term landscape changes, assess soil health, and develop strategies for sustainable land use.
The Munsell Soil Color Chart is particularly valuable in tracking environmental shifts. Subtle variations in soil color can indicate changes in moisture levels, organic content, or chemical composition—factors that influence everything from erosion control to habitat restoration. Soil analysis can reveal how a site has responded to past land use or whether a conservation area is recovering as expected.
By decoding soil characteristics with precision, environmental professionals can make informed decisions that support healthy ecosystems, improve water management, and guide responsible development. The Munsell Soil Color Chart remains a trusted resource in this process, providing a universal language for soil classification and environmental assessment.
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!
We are thrilled to announce the newest addition to our fleet: The Marsh Master® 2MX-KC-FH! This multi-functional, eco-friendly, and fully amphibious machine is specifically designed to work in wetland environments with minimal disruption to the delicate ecosystem.
One of the Marsh Master®'s primary roles is combating invasive and nuisance plant species, including the notorious non-native Phragmites australis, also known as Common Reed. Utilizing its innovative leveling and cutting mechanisms, this powerhouse of a machine efficiently knocks down and chops up sprayed or winter-weakened vegetation. Equipped with two powerful rotary blades, it effortlessly cuts through dense underbrush and tall marsh grasses, effectively controlling invasive weeds and problematic plant growth.
"We are committed to offering more non-chemical alternatives for aquatic invasive species control. The Marsh Master® 2MX-KC-FH is the second marsh buggy in our fleet," said Geoffrey M. Goll, President of Princeton Hydro. "This model is larger and more powerful, allowing us to cover more ground in a shorter period of time. Adding this machine to our fleet is an important investment in achieving our firm's environmental stewardship goals."
What sets the Marsh Master® apart is its versatility and low environmental impact. With its lightweight construction and advanced weight distribution system, it exerts low ground pressure and boasts high floating capacity. This allows the Marsh Master® to operate seamlessly on water, in deep or shallow depths, and on dry land without disturbing sensitive environments like nature preserves, wetlands, and canal banks. Its highly maneuverable design ensures easy passage through narrow channels and around hazards, making it the ideal choice for a wide range of applications.
But the Marsh Master® is not just a one-trick pony. With a wide array of tools and accessories, it can perform a variety of functions, from weed cutting and harvesting to debris removal to excavation to soil sampling.
During a recent project in Middlesex County, we put the Marsh Master® to the test to clear an area overrun with Phragmites australis. These invasive weeds not only create dense thickets unsuitable for native fauna but also outcompete local vegetation, leading to a decrease in plant diversity. Thanks to the Marsh Master®'s efficient cutting and rolling capabilities, we were able to expose the marsh plain and get it ready for planting of native vegetation in the Spring. This is just one example of how the Marsh Master is making a tangible difference in restoring delicate ecosystems.
Through a combination of prevention, early detection, eradication, restoration, research and outreach, we can protect our native landscapes and reduce the spread of invasive species. Learn more about our invasive species removal and restoration services.
In Warrington Township, Pennsylvania, an innovative ecological uplift initiative is underway at Lion's Pride Park. This project aims to transform a stagnant pond, overrun with invasive species and plagued by water quality issues, into a thriving wetland mosaic. This endeavor, a collaborative effort between Warrington Township, Princeton Hydro, and other stakeholders, promises to not only revitalize the natural environment but also enhance community access and education within the park.
Spanning 47 acres, Lion's Pride Park serves as a green oasis within the Township, offering a range of recreational and educational opportunities for visitors of all ages and abilities.
The pond within the park was in urgent need of restoration - heavy storm events caused the pond to overflow, which created flooding conditions in the park. The local native biodiversity was being threatened by nusiance and invasive species like water chestnut (Trapa natans). The photos below were taken in April 2020.
Princeton Hydro began in 2020 with site investigation and field surveys, including:
The most substantial component for the restoration project was the conversion of the existing pond to an emergent wetland complex to provide habitat for a wide variety of native species. Using the completed existing conditions reports and surveys, Princeton Hydro prepared the conceptual design plan that informed the entire restoration process.
Princeton Hydro Regulatory Compliance & Wildlife Surveys Project Manager Emily Bjorhus, PWS spearheaded the regulatory program for the project, navigating approvals from the Pennsylvania Department of Environmental Protection (PADEP), the U.S. Army Corps of Engineers (USACE), and the Bucks County Conservation District. The permitting process laid the groundwork for the smooth implementation of this design-build restoration project.
The restoration work encompassed various stages, from earthwork and vegetation planting to the installation of ADA-compliant pathways and informational signage. Some of the key project elements, include:
Channel stabilization: Stabilizing the channels within the park, addressing erosion issues, enhancing water flow dynamics, and promoting the establishment of diverse aquatic habitats.
Berm construction: Installing berms to enhance wetland habitat and promote natural floodplain connectivity, contributing to the resilience of the ecosystem to flooding events.
Native vegetation planting: Reintroducing native wetland and riparian plant species to enhance biodiversity and create habitat corridors for wildlife within the park. Planting is expected to take place in the Spring.
Boardwalk installation: Constructing a 6-foot-wide ADA-compliant boardwalk that spanned approximately 230 linear feet, providing visitors with accessible pathways to explore the restored wetland areas.
Through these strategic interventions, the Lion's Pride Park Ecological Restoration Project aims to not only rejuvenate the ecological integrity of landscape but also enrich the recreational and educational experiences of the community. The project, which is slated for 100% completion this Spring, will totally transform the landscape into a diverse wetland complex that fosters native wildlife habitat, mitigates water quality concerns, reduces nonpoint source pollutants discharged to downstream waters, and provides accessible pathways and observation platforms so all community members may enjoy and learn from this restored aquatic setting.
The reclaimed wetland provides additional bird and pollinator habitat and offer visitors a diverse ecosystem to learn from within the park. By fostering a deeper connection to nature and promoting environmental stewardship, this project exemplifies the transformative power of ecological restoration in creating vibrant, sustainable communities.
On March 23, at the 2024 Watershed Congress hosted by the Delaware Riverkeeper Network, Emily will be presenting about the Lion's Pride Park Ecological Restoration Project. Her presentation will offer insights into the regulatory approval and permitting process, takes a deeper dive into the restoration strategies, and showcases the ecological significance of the project. Click here to learn more about the 2024 Watershed Congress.
Emily, a certified Professional Wetland Scientist, is a Project Manager that specializes in environmental regulatory compliance, ecological services and wildlife surveys. She leads federal, state and local environmental permitting processes, NEPA compliance and documentation, Endangered Species Act Section 7 consultations, and Clean Water Act Section 404(b)1 analyses.
The Lion's Pride Park Ecological Restoration Project exemplifies a holistic approach to environmental conservation, community engagement, and public recreation. By repurposing a neglected pond into a vibrant wetland mosaic, this initiative embodies the principles of ecological resilience and inclusive urban planning, and celebrates the transformative potential of ecological uplift projects in fostering healthier, more vibrant communities.
Please stay tuned to our blog for more project updates once planting is completed this Spring. Click here to read more about Princeton Hydro’s robust natural resource management and restoration services.
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