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[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.
Harmful Algal Blooms (HABs) represent the rapid proliferation of cyanobacteria, also known as blue-green algae. While cyanobacteria are not technically algae but rather single-celled aquatic organisms related to bacteria, they possess the ability to photosynthesize like algae. These tiny microorganisms naturally inhabit aquatic ecosystems. However, under specific circumstances, such as heavy rainfall followed by scorching sunshine, they can rapidly multiply, resulting in the formation of cyanobacteria blooms, commonly known as HABs.
HABs can wreak havoc on waterbodies, leading to significant water quality issues and the unsightly appearance of surface scum, sometimes accompanied by unpleasant odors. The consequences extend beyond aesthetics and pose economic challenges for communities reliant on local lakes and waterways for jobs and tourism. Furthermore, HABs can produce highly toxic substances that pose serious risks to humans, aquatic life, and animals, including our beloved pets, wildlife, and livestock.
The effects of HABs on animals vary depending on factors such as the animal's size, exposure to cyanobacteria, duration of exposure, specific toxin types, and concentrations. Animals are often the first victims, drawn to bodies of water containing cyanobacteria due to their natural instincts. Dogs, in particular, are vulnerable as they may unwittingly ingest contaminated water during play. Livestock and wildlife are also at risk when drinking from contaminated water sources.
In 2021, researchers published a groundbreaking study linking cyanobacteria-generated neurotoxins to the deaths of eagles and waterbirds. After extensive research spanning three decades, scientists determined that cyanotoxins are responsible for a fatal neurological disease called vacuolar myelinopathy, commonly affecting waterbirds, raptors, and bald eagles.
Cyanobacterial poisoning symptoms can manifest within minutes to a few hours, depending on the severity of exposure. Dogs, in particular, may exhibit symptoms rapidly. Common signs include an accelerated heart rate, breathing difficulties, excessive salivation, disorientation or depression, vomiting or diarrhea, skin irritations, and neurological symptoms such as muscle weakness, dizziness, seizures, or paralysis.
It is crucial to seek immediate veterinary care or contact the Poison Control Center if you suspect your pet or livestock may be experiencing symptoms caused by harmful algae, cyanobacteria, or their toxins. The following 24-hour pet poison hotlines are available for assistance:
To protect your pets and livestock, avoid letting them come into contact with surface scums or heavily discolored water. In case of exposure, rinse them with clean water as soon as possible, as HABs can cling to their fur and pose health risks when they groom themselves. This is particularly important because certain HABs release fast-acting nerve toxins that can be especially dangerous for dogs swimming in affected areas.
Here are some additional steps you can take to safeguard yourself and your pets from the harmful effects of algae and cyanobacteria:
By staying informed and implementing necessary precautions, we can protect ourselves, our pets, and the environment from the risks associated with HABs. For further HABs related information and guidance, click here to watch a Facebook Live presentation with Princeton Hydro HABs experts. To get involved with monitoring and tracking harmful algal blooms, check out the bloomWatch App, a valuable tool for identifying and reporting potential HAB sightings to local authorities.
Most of us are familiar with the famous quote "Alone we can do so little; together we can do so much.” This sentiment is at the center point of the Highlands Act and Regional Master Plan, which provides funding to help New Jersey’s Highlands communities take a proactive and regional approach to watershed protection.
Historically, private lake associations and municipalities have worked autonomously to address water quality issues and develop improvement plans. Working together, however, and taking a regional approach to lake and watershed management has much farther-reaching benefits. Taking an integrated approach helps improve water quality and reduce incidents of aquatic invasive species and harmful algal blooms (HABs) not just in one waterbody, but throughout an entire region.
The New Jersey Highlands Water Protection and Planning Council (Highlands Council) is a regional planning agency that works in partnership with municipalities and counties in the Highlands Region of northern New Jersey to encourage exactly such an approach. Created as part of the 2004 New Jersey Highlands Water Protection and Planning Act (the Highlands Act), the Highlands Council has funded numerous water-quality-related planning grants throughout the region.
“Watersheds are inherently regional; they don’t follow municipal boundaries. So the Highlands Council is in a unique position to address these challenges from that perspective,” says Keri Green, Highlands Council Science Manager. “It’s critical for municipalities to understand what is entering their lakes from the surrounding watershed before they can effectively address in-lake issues. Across the region, the stormwater inlets and roadways that encircle and affect lakes are owned and maintained by the municipalities, and when we can evaluate these inputs, we can plan for how to address impairments.”
In 2019, the Highlands Council funded a Lake Management planning grant for the Borough of Ringwood that adopted this wider watershed view, and would ultimately become a model for similar Highlands Council grants within the region. The Borough chose to engage the services of Princeton Hydro to support the project work.
“This regional approach to lake and watershed management is the obvious choice from a scientific, technical, and community point of view. Historically, however, this approach is rarely taken,” said Princeton Hydro’s Senior Project Manager, Christopher Mikolajczyk, who is a Certified Lake Manager and lead designer for this initiative. “We were thrilled to work with the Borough of Ringwood and the Highlands Council to set a precedent, which has opened the door for the Townships of West Milford and Rockaway, and will hopefully inspire the formation of more public-private lake management partnerships.”
Rockaway Township in Morris County, New Jersey received Highlands Council grant approval in January to complete a Lake Management Planning Study. Eleven small- to medium-sized lakes in the township are working together for a watershed assessment and comprehensive regional analysis, which will lead to the creation of a Watershed Implementation Plan (WIP). The WIP will recommend and prioritize key watershed management measures that will have big impacts on water quality improvement.
Given the large number of lakes in Rockaway Township, and in an effort to keep the study to a reasonable scope, a selection process occurred with input from the Township Engineering office, the Township Health Department, Princeton Hydro and the Highlands Council. The lakes in the Rockaway Township Watershed Management Program include Green Pond, Egbert Lake, Durham Pond, Lake Emma, Camp Lewis Lake, Lake Telemark, Lake Ames, Mount Hope Pond, Mount Hope Lake, White Meadow Lake, and Fox’s Pond.
“Rockaway Township has been proactive about implementing watershed improvement projects in the past, so we were happy to provide funding to support continuing their efforts focusing on these 11 lakes,” explains Lisa Plevin, Highlands Council Executive Director. “It was a very productive collaboration with Highlands staff working in partnership with the Township to develop an approach and Princeton Hydro preparing a scope of work that met everyone’s goals.”
The watershed assessment will entail a number of analyses, including watershed modeling; hydrologic and pollutant loading analysis; watershed-based and in-lake water quality assessments; and tropic state assessments. The assessment aims to:
Once all the lab data is processed, the watershed modeling is complete, and historical data reviewed, Princeton Hydro will create a General Assessment Report that will summarize the data/observations and identify which watershed management techniques and measures are best suited for immediate or long-term implementation. The team expects to complete the General Assessment Report in the spring of 2022, after a year's worth of 2021 growing season data has been collected.
In October 2020, the Highlands Council approved funding to support a watershed assessment of 22 private and public lakes in West Milford Township. The watershed assessment project is being implemented in two phases:
For Phase 1, which will take place throughout the course of 2021, Princeton Hydro will provide a historic data review; an examination of hydrologic/pollutant loads; a pollutant removal analysis; and watershed water quality analysis. The pollutants to be modeled include phosphorus, nitrogen, sediment, and bacteria, while the hydrology will include estimates of precipitation, runoff, evapotranspiration, groundwater flux, and ultimately streamflow or discharge.
This analysis will aid the Township in selecting, prioritizing and implementing nutrient and sediment load and stormwater management efforts with a focus on watershed projects that have the greatest overall benefit to the long-term management of surface water quality. The report will also identify examples of site-specific locations where wetland buffers, riparian buffers, and lakefront aqua-scaping can be implemented as part of future watershed management efforts.
For Phase 2 of the project, Princeton Hydro will investigate and assess the water quality of each of the lakes in West Milford Township during the growing season of May - October of 2022. This entails collecting bimonthly water quality samples at each lake, including in-situ water quality data consisting of real-time measurement of clarity, dissolved oxygen, temperature, and pH. The sampling events will also include a general survey of aquatic vegetation and/or algae growth, lake perimeter shoreline observations, and monitoring for nuisance waterfowl. These surveys will provide an objective understanding of the amount and distribution of submerged aquatic vegetation (SAV) and algae occurring throughout each lake over the course of the growing season.
The lakes included in this project are: High Crest Lake, Algonquin Waters, Lake Lookover, Kitchell Lake, Lindys Lake, Mt. Laurel Lake, Shady Lake, Wonder Lake, Mount Glen Lakes (Upper/Lower), Carpi Lake, Pinecliff Lake, Van Nostrand Lake, Upper Greenwood Lake, Post Brook Farms, Farm Crest Acres, Mt. Springs Lake, Forest Hill Park, Johns Lake, Gordon Lake, and Bubbling Springs Lake.
At the end of 2019, the Borough of Ringwood became the first municipality in New Jersey to take a regional approach to private lake management through a public-private partnership with four lake associations: Cupsaw, Erskine, Skyline, and Riconda.
The Borough of Ringwood is situated in the northeast corner of the New Jersey Highlands, is home to several public and private lakes, and provides drinking water to millions of New Jersey residents. In order to take an active role in the management of these natural resources, Ringwood hired Princeton Hydro to design a municipal-wide holistic watershed management plan that identifies and prioritizes watershed management techniques and measures that are best suited for immediate and long-term implementation.
Princeton Hydro recently completed a comprehensive assessment of the lakes and watersheds of Ringwood Borough. The assessment included a historical data review, hydrologic and pollutant loading analysis and in-lake and watershed based water quality data studies. The report details the results of Princeton Hydro’s mapping, modeling, and monitoring efforts in each waterbody and its respective watershed, along with specific recommendations for management implementations that are aimed at curbing the effects of nutrient and sediment loading, both within the lakes and their respective watersheds.
“Ringwood, West Milford, and Rockaway are three great examples of how people from different affiliations and backgrounds can come together to address lake and watershed monitoring and management,” said Mikolajczyk. “The key to success is open communication and a common goal!”
To learn more about Princeton Hydro’s natural resource management services, click here. And, click here to learn more about NJ Highlands Council and available grant funding.
Looking for a unique and creative way to manage nutrient runoff in freshwater lakes? Installing Floating Wetland Islands (FWI) is a low-cost, effective green infrastructure solution used to mitigate phosporus and nitrogen stormwater pollution often emanating from highly developed communities and/or argricultural lands.
FWIs are designed to mimic natural wetlands in a sustainable, efficient, and powerful way. They improve water quality by assimilating and removing excess nutrients that could fuel algae growth; provide valuable ecological habitat for a variety of beneficial species; help mitigate wave and wind erosion impacts; provide an aesthetic element; and add significant biodiversity enhancement within open freshwater environments.
“A pound of phosphorus can produce 1,100 lbs of algae each year. And, each 250-square foot island can remove 10 lbs of phosphorus annually.” explains Princeton Hydro Staff Scientist Katie Walston. "So, that's 11,000 lbs of algae that is mitigated each year from each 250 square foot of FWI installed!"
Typically, FWIs consist of a constructed floating mat with vegetation planted directly into the material. Once the islands are anchored in the lake, the plants thrive and grow, extending their root systems through the mat and absorbing and removing excess nutrients from the water column such as phosphorus and nitrogen.
The plants uptake a lot of nutrients, but the workhorse of the FWIs is the microbial community. The matrix used within the islands has a very high surface area and it promotes microbial growth, which performs the majority of the nutrient uptake. Additionally, the root growth from the plants continues to increase the surface area for the microbial biofilm to grow on. Both the plants and microbes acting together help optimize nutrient removal.
Princeton Hydro has designed and installed numerous FWIs in waterbodies large and small for the purpose of harmful algal bloom control, fisheries enhancement, stormwater management, shoreline preservation, wastewater treatment, and more. FWIs are also highly adaptable and can be sized, configured, and planted to fit the needs of nearly any lake, pond, or reservoir.
Recently, the Princeton Hydro team completed a FWI installation in Belcher's Creek, the main tributary of Greenwood Lake. The lake, a 1,920-acre waterbody located in both Passaic County, New Jersey and Orange County, New York, is a highly valued ecological and recreational resource for both states and has a substantial impact on the local economies. In addition, the lake serves as a headwater supply of potable water that flows to the Monksville Reservoir and eventually into the Wanaque Reservoir, where it supplies over 3 million people and thousands of businesses with drinking water.
Since the lake was negatively impacted by HABs during the 2019 summer season, Greenwood Lake Commission (GWLC) has made a stronger effort to eliminate HABs and any factors that contribute to cyanobacteria blooms for 2020 and into the future. Factors being addressed include pollutant loading in the watershed, especially that of Belcher's Creek. The installation of FWIs in Belcher's Creek will immediately address nutrients in the water before it enters Greenwood Lake and help decrease total phosphorus loading. In turn this will help reduce HABs, improve water quality throughout the Greenwood Lake watershed, and create important habitat for beneficial aquatic, insect, bird and wildlife species.
“In addition to the direct environmental benefits of FWIs, the planting events themselves, which involve individuals from the local lake communities, have long-lasting positive impacts,” said Dr. Jack Szczepanski, Princeton Hydro Senior Project Manager, Aquatics Resources. “When community members come together to help plant FWIs, it gives them a deepened sense of ownership and strengthens their connection to the lake. This, in turn, encourages continued stewardship of the watershed and creates a broader awareness of how human behaviors impact the lake and its water quality. And, real water quality improvements begin at the watershed level with how people treat their land.”
The project was partially funded by the New Jersey Department of Environmental Protection's (NJDEP) Water Quality Restoration Grants for Nonpoint Source Pollution Program under Section 319(h) of the federal Clean Water Act. As part of the statewide HAB response strategy, the NJDEP made $13.5 million in funding available for local projects that improve water quality and help prevent, mitigate and manage HABs in the state’s lakes and ponds. The GWLC was awarded one of the NJDEPs matching grants, which provided $2 in funding for every $1 invested by the grant applicant. For this project, the GWLC purchased the FWIs and NJDEP provided the 2:1 cash match in order for the GWLC to implement additional HAB prevention and mitigation strategies in critical locations throughout the watershed.
Over the coming weeks, our team will be in Asbury Park, New Jersey installing FWIs in Sunset Lake. Stay tuned for more! For additional information about our lake management services, go here: bit.ly/pondlake.
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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.
Collaboration between state agencies and local organizations in Luzerne County bring in grant money to determine Hydrilla infestation levels in Harveys Lake. Treatment efforts are scheduled for 2019.
Story provided by Princeton Hydro Senior Limnologist Michael Hartshorne, and originally published in the Pennsylvania iMapInvasives Fall 2018 Newsletter
Harveys Lake, located in the Borough of Harveys Lake (Luzerne County) is a large, deep glacial lake with limited littoral (i.e., shoreline) habitat. A significant body of work has been conducted at the lake with the original Phase I: Diagnostic-Feasibility Lake study conducted in 1992 and a Total Maximum Daily Load (TMDL) issued for phosphorus in 2002.
From 2002 to present, Princeton Hydro has assisted the Borough in the restoration of the lake with a heavy focus on stormwater best management practices (BMPs) supplemented by routine, in-lake water quality monitoring. The goal of the storm water/watershed-based efforts was to reduce the lake’s existing, annual total Hydrilla (Hydrilla verticillata) phosphorus load so it’s in full compliance with the established TMDL.
Over the last 15 years, the installation of these watershed-based projects has led to improved water quality conditions; specifically, phosphorus and algae concentrations have been reduced. While water quality conditions improved Harveys Lake, it was during one of the routine, summer water quality monitoring events conducted in July 2014 that a dense stand of hydrilla was noted at the Pennsylvania Fish and Boat Commission’s public boat launch. More than likely, the plant entered the lake as a “hitchhiker” on the boat or trailer being launched from this public boat launch by someone visiting the lake.
Since the initial identification and confirmation of the hydrilla, the Borough of Harveys Lake has worked in conjunction with the Harveys Lake Environmental Advisory Council, the Luzerne County Conservation District, the Pennsylvania Department of Environmental Protection, and Princeton Hydro to secure funding for additional surveys to determine the spatial extent and density of growth followed by an aggressive eradication plan.
Grant funds already allocated to Harveys Lake under the state’s Non-Point Source Pollution Program were used to conduct a detailed boat-based and diving aquatic plant survey of Harveys Lake to delineate the distribution and relative abundance of the hydrilla in 2014. During these surveys, the distribution of the hydrilla was found to be limited to the northern portion of the lake with the heaviest densities just off the boat launch with plants observed growing in waters 20-25 feet deep.
A follow-up survey had shown hydrilla coverage to increase from 38% of surveyed sites to 58% of sites in 2016 with hydrilla now present at the lake’s outlet area. Spatial coverage of hydrilla increased from approximately 50 acres in 2014 to 210 acres in 2016, an increase of 160 acres.
In hopes of preventing hydrilla escaping into the lake’s outlet stream, the Borough of Harveys Lake funded an emergency treatment of the two-acre outlet area in 2016 utilizing the systemic herbicide Sonar® (Fluridone). A follow-up treatment of 159 acres was conducted in 2017, again utilizing the Fluridone-based systemic herbicide.
The next treatment, which will attempt to cover the majority of the littoral habitat covered by hydrilla, is scheduled for late spring/early summer of 2019. It should be noted that Sonar® is being applied at a low concentration that is effective at eradicating the hydrilla, but will not negatively impact desirable native plant species.
The treatments conducted to date have documented some reductions in the vegetative coverage of hydrilla as well as tuber production relative to the original plant surveys conducted in 2016. However, it is recognized that it will take multiple years of treatment to eradicate this nuisance plant from the lake, as well as a highly proactive, interactive program to educate residents as well as visitors to the lake in preventing the re-introduction of this or other invasive species to Harveys Lake.
The successful, long-term improvement of a lake or pond requires a proactive management approach that addresses the beyond simply reacting to weed and algae growth and other symptoms of eutrophication. Our staff can design and implement holistic, ecologically-sound solutions for the most difficult weed and algae challenges. Visit our website to learn more about Princeton Hydro's lake management services: http://bit.ly/pondlake
Michael Hartshorne's primary areas of expertise include lake and stream diagnostic studies, TMDL development, watershed management, and small pond management and lake restoration. He is particularly skilled in all facets of water quality characterization, from field data collection to subsequent statistical analysis, modeling, technical reporting, and the selection and implementation of best management practices. He has extensive experience in utilizing water quality data in concert with statistical and modeling packages to support load reduction allocations for the achievement of water quality standards or tailored thresholds set forth to reduce the rate of cultural eutrophication. He also has significant experience in conducting detailed macrophyte, fishery, and benthic surveys.
Freshwater mussels are among the oldest living and second most diverse organisms on Earth with over 1,000 recognized species. Here in the eastern part of the U.S., we have more species of freshwater mussels than anywhere in the world. Unfortunately, freshwater mussels are one of the most rapidly declining animal groups in North America. Out of the 300 species and subspecies found on the continent, 70 (23%) have been federally listed as "Threatened" or "Endangered" under the Endangered Species Act. And, in the last century, over 30 species have become permanently extinct. So, why are populations declining so fast?
Freshwater mussels are filter feeders and process large volumes of the water they live in to obtain food. This means of survival also makes them highly susceptible to industrial and agricultural water pollution. Because they are constantly filtering water, the contaminants and pathogens that are present are absorbed into the mussel’s tissues. As such, mussels are good indicators of water quality and can greatly contribute to improving water quality by filtering algae, bacteria and organic matter from the water column.
Not only do freshwater mussels rely on water quality, they are dependent on fish and other aquatic organisms for reproductive success. In order for a freshwater mussel to complete the reproduction process, it must “infect” a host fish with its larvae. The method depends on the specie of mussel. Some species lure fish using highly modified and evolved appendages that mimic prey. When a fish goes into investigate the lures, the female mussel releases fertilized eggs that attach to the fish, becoming temporarily parasitic. Once the host fish is infected, it can transfer the mussel larvae upstream and into new areas of the river.
Both habitat loss from dam construction and the introduction of pesticides into the water supply has contributed to the decline of freshwater mussels. With approximately 300 mussel species in the U.S. alone, a critical component of restoring and revitalizing mussel populations is truly understanding their biology, which begins with the ability to properly differentiate each species and properly identify and catalog them. Princeton Hydro’s Senior Scientist Evan Kwityn, CLP and Aquatic Ecologist Jesse Smith recently completed the U.S. Fish and Wildlife Service's Fresh Water Mussel Identification Training at the National Conservation Training Center in West Virginia.
Through hands-on laboratory training, Evan and Jesse developed their freshwater mussel identification skills and their knowledge of freshwater mussel species biology. Course participants were tasked with mastering approximately 100 of the most common freshwater mussel species in the United States. They also learned about proper freshwater mussel collection labeling, the internal and external anatomy and meristics of a freshwater mussel, and distributional maps as an aid to freshwater mussel identification.
In a recently published press release, Tierra Curry, a senior scientist with the Center for Biological Diversity was quoted as saying, “The health of freshwater mussels directly reflects river health, so protecting the places where these mussels live will help all of us who rely on clean water. This is especially important now, when we see growing threats to clean water from climate change, agriculture and other sources.”
Princeton Hydro is committed to protecting water quality, restoring habitats, and managing natural resources. Read about some of our recent projects and contact us to discuss how we can help you.
To learn more about freshwater mussels, check out this video from U.S. Fish and Wildlife Service.
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