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 ( [tag] => invasive-species ) [query_vars] => Array ( [tag] => invasive-species [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 [category_name] => stormwater [cat] => 40 [tag_id] => 567 [author] => [author_name] => [feed] => [tb] => [paged] => 1 [meta_key] => [meta_value] => [preview] => [s] => [sentence] => [title] => [fields] => all [menu_order] => [embed] => [category__in] => Array ( [0] => 40 ) [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 ( [0] => invasive-species ) [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] => 40 ) [field] => term_id [operator] => IN [include_children] => ) [1] => Array ( [taxonomy] => post_tag [terms] => Array ( [0] => invasive-species ) [field] => slug [operator] => IN [include_children] => 1 ) ) [relation] => AND [table_aliases:protected] => Array ( [0] => ph_term_relationships [1] => tt1 ) [queried_terms] => Array ( [category] => Array ( [terms] => Array ( [0] => 40 ) [field] => term_id ) [post_tag] => Array ( [terms] => Array ( [0] => invasive-species ) [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] => 567 [name] => Invasive Species [slug] => invasive-species [term_group] => 0 [term_taxonomy_id] => 567 [taxonomy] => post_tag [description] => [parent] => 0 [count] => 45 [filter] => raw [term_order] => 0 ) [queried_object_id] => 567 [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 (40) AND tt1.term_taxonomy_id IN (567) ) 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] => 17748 [post_author] => 1 [post_date] => 2025-07-08 09:52:44 [post_date_gmt] => 2025-07-08 09:52:44 [post_content] => 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. [gallery link="none" columns="4" size="medium" ids="17787,17788,7339,17789"] 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. Understanding the Impacts of Invasive Species 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:
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.
Measuring 630+ acres, Harveys Lake, located in Luzerne County, Pennsylvania, just northeast of Wilkes-Barre, is the largest natural lake (by volume) within the Commonwealth of Pennsylvania, and is one of the most heavily used lakes in the area. It is classified as a high quality - cold water fishery habitat (HQ-CWF) and is designated for protection under the classification.
Since 2002, The Borough of Harveys Lake and the Harveys Lake Environmental Advisory Council has worked with Princeton Hydro on a variety of lake management efforts focused around maintaining high water quality conditions, strengthening stream banks and shorelines, and managing stormwater runoff.
Successful, sustainable lake management requires identifying and correcting the cause of eutrophication as opposed to simply reacting to the symptoms of eutrophication (algae and weed growth). As such, we collect and analyze data to identify the problem sources and use these scientific findings to develop a customized management plan that includes a combination of biological, mechanical, and source control solutions. Here are some examples of the lake management strategies we've utilized for Harveys Lake:
Floating Wetland Islands (FWIs) are an effective alternative to large, watershed-based natural wetlands. Often described as self-sustaining, FWIs provide numerous ecological benefits. They assimilate and remove excess nutrients, like nitrate and phosphorous, that could fuel algae growth; provide habitat for fish and other aquatic organisms; help mitigate wave and wind erosion impacts; and provide an aesthetic element. FWIs are also highly adaptable and can be sized, configured, and planted to fit the needs of nearly any lake, pond, or reservoir.
Five floating wetland islands were installed in Harveys Lake to assimilate and reduce nutrients already in the lake. The islands were placed in areas with high concentrations of nutrients, placed 50 feet from the shoreline and tethered in place with steel cables and anchored. A 250-square-foot FWI is estimated to remove up to 10 pounds of nutrients per year, which is significant when it comes to algae.
Princeton Hydro worked with the Harveys Lake Environmental Advisory Council and the Borough of Harveys Lake to obtain funding for the FWIs through the Pennsylvania Department of Environmental Protection (PADEP).
The shoreline habitat of Harveys Lake is minimal and unusual in that a paved road encompasses the lake along the shore with most of the homes and cottages located across the roadway, opposite the lake. In addition to the lake being located in a highly populated area, the limited shoreline area adds to the challenges created by urban stormwater runoff.
Runoff from urban lands and erosion of streambanks and shorelines delivers nutrients and sediment to Harveys Lake. High nutrient levels in the lake contribute to algal blooms and other water quality issues. In order to address these challenges, the project team implemented a number of small-scale streambank and inlet stabilization projects with big impacts.
The work included the stabilization of the streambank downstream for Harveys Lake dam and along Harveys Creek, the design and installation of a riparian buffer immediately along the lake’s shoreline, and selective dredging to remove sediment build up in critical areas throughout the watershed.
Hydrilla (Hydrilla verticillata), an aggressively growing aquatic plant, took root in the lake in 2014 and quickly infected 250 acres of the lake in a matter of three years. If left untreated, hydrilla will grow to the water’s surface and create a thick green mat, which prevents sunlight from reaching native plants, fish and other organisms below. The lack of sunlight chokes out all aquatic life.
In order to prevent hydrilla from spreading any further, Princeton Hydro and SePRO conducted an emergency treatment of the impacted area utilizing the systemic herbicide Sonar® (Fluridone), a clay-based herbicide. SonarOne, manufactured by SePRO, blocks hydrilla’s ability to produce chloroplasts, which in turn halts the photosynthetic process. The low-concentration herbicide does not harm fish, wildlife or people using the lake. Surveys conducted after the treatment showed it was working – the hydrilla had turned white and was dying off. Additional Sonar treatments followed and efforts to eradicate hydrilla in the lake continue.
Dr. Fred Lubnow, our Director of Aquatic Programs, estimates complete eradication of the aquatic plant could take around five years. Everyone can do their part in preventing the spread of this and other invasive species. Boaters and lake users must be vigilant and remove all vegetation from the bottom of watercrafts and trailers.
In 2009, Princeton Hydro developed a stormwater implementation plan (SIP) for Harveys Lake. The goal of the stormwater/watershed-based efforts was to reduce the lake’s existing annual total phosphorus load to be in full compliance with the established Total Maximum Daily Load (TMDL). This TMDL is related to watershed-based pollutant loads from total phosphorus (TP) and total suspended solids (TSS), which can contribute to algal blooms.
A number of structural urban runoff projects were implemented throughout the watershed. This includes the design and construction of two natural stream channel projects restoring 500 linear feet of tributaries and reducing the sediment and nutrient loads entering the lake. A series of 38 urban runoff BMPs, including nutrient separating devices and roadside infiltration, were installed in areas immediately adjacent to the lake to further reduce the loads of nutrients and other pollutants reaching the lake.
The photos below show a stormwater project that was completed in the Hemlock Gardens Section of the Watershed. Hemlock Gardens is a 28-acre section of land located in the southeastern portion of the watershed. It contains approximately 26 homes, has very steep slopes, unpaved dirt roads, and previously had no stormwater infrastructure in place.
Two structural stormwater BMPs were installed:
In 1994, Harveys Lake was identified as “impaired” by PADEP due to large algal blooms. In 2014, Harveys Lake was removed from the list of impaired waters. Project partners attribute the recovery of this lake to the stream restoration, urban runoff BMP implementation, and the use of in-lake nutrient reduction strategies.
The Harveys Lake Watershed Protection Plan Implementation Project proved that despite the lake being located in an urbanized watershed, it is possible to implement cost-effective green infrastructure and stormwater retrofit solutions capable of significantly decreasing pollutant loading to the lake.
…
Volunteers recently gathered together at Clawson Park in Ringoes, NJ to install native plants in the park’s large stormwater basin and overhaul two of the park’s rain gardens, removing invasive weeds and planting beneficial native species.
By definition, a rain garden is a shallow depression that is planted with deep-rooted native plants and grasses and positioned near a runoff source to capture rainwater. Rain gardens temporarily store rainwater and runoff, and filter the water of hydrocarbons, oil, heavy metals, phosphorous, fertilizers and other pollutants that would normally find their way to the sewer and even our rivers and waterways. They are a cost effective, attractive, and sustainable way to minimize stormwater runoff. They also help to reduce erosion, promote groundwater recharge, and minimize flooding. Planting native plants helps to attract pollinators and birds and naturally reduces mosquitoes by removing standing water thus reducing mosquito breeding areas.
Once a rain garden has been established, it is low maintenance and typically only requires occasional weeding to remove any invasive species that may have cropped up. The recent volunteer effort, lead by Jack Szczepanski, PhD, Senior Aquatics Scientist, was an important step in maintaining the health and native diversity of Clawson Park’s rain gardens.
The park’s rain gardens and stormwater basins were originally designed and implemented by Princeton Hydro. Back in 2016, Eagle Scout Brandon Diacont had an idea to beautify Clawson Park and improve the park’s stormwater drainage issues. Princeton Hydro supported his vision by developing, permitting, and implementing a stormwater management project plan, which included the installation of multiple rain gardens throughout the park. In October of 2016, under the guidance of Princeton Hydro’s Landscape Designer Cory Speroff, MLA, ASLA, CBLP, a great group of volunteers gathered together and got to work bringing the project plan to life!
The Princeton Hydro team has designed and constructed countless stormwater management systems, including rain gardens in locations throughout the Eastern U.S. Click here for more information about our stormwater management services.
Stay Tuned for More 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