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The New Jersey Department of Environmental Protection (NJDEP) recently announced $8 million in Water Quality Restoration Grants to support projects that reduce nonpoint source pollution, mitigate harmful algal blooms, restore riparian areas, and enhance watershed and climate resilience. Funded through Section 319(h) of the federal Clean Water Act and administered by the DEP's Watershed and Land Management Program, these grants were awarded to municipalities, nonprofit organizations, and academic institutions across the state.

Princeton Hydro is proud to be a partner on five of the 17 funded projects. Our contributions vary by project and encompass activities such as engineering design, water quality assessment, watershed-based planning, and technical support for implementing stormwater and habitat restoration measures. Let's take a deeper look at these collaborative efforts:

1. The Watershed Institute – Watershed-Based Planning for Assunpink Creek

The Watershed Institute received $205K in 319(h) grant funding to develop a watershed-based plan for the Assunpink Creek watershed, located within the Raritan River Basin. This watershed spans 11 municipalities across two counties, where varied landscapes and demographics share common challenges such as localized flooding, stormwater management, and water quality degradation, highlighting the need for a coordinated, watershed-wide, science-driven approach.

The plan will evaluate pollution sources and identify large-scale restoration opportunities, including green infrastructure and riparian buffer restoration, to improve water quality and reduce flooding. It will also assess the cost, feasibility, and pollutant reduction potential of proposed measures to ensure practical implementation. Princeton Hydro supported the Institute in developing the grant proposal and planning framework, leveraging our expertise in watershed-based planning to prioritize nature-based solutions that address both water quality and climate resilience. This initiative represents a critical step toward regional collaboration, enabling upstream and downstream communities to work together on strategies that strengthen watershed health, protect public safety, and build long-term resilience.


2. Lake Hopatcong Commission – Watershed-Based Stormwater BMPs

The Lake Hopatcong Commission (LHC) was awarded $366K to retrofit an existing stormwater detention basin between King Road and Mount Arlington Boulevard in Roxbury Township. This retrofit is part of a larger Watershed Implementation Plan that Princeton Hydro developed in collaboration with LHC, which prioritizes nutrient reduction and stormwater management strategies across the Lake Hopatcong watershed. Over the past several years, LHC has actively implemented multiple elements of this plan to address harmful algal blooms (HABs) and improve water quality.

For this project, Princeton Hydro is providing engineering design and technical oversight to transform the existing basin into a green stormwater infrastructure system that slows, captures, and naturally treats runoff before it enters King Cove. The design incorporates native vegetation, invasive species management, and erosion control measures to stabilize soils and filter pollutants, reducing nutrient loading, which is one key driver of HABs. Public outreach and pre- and post-construction water quality monitoring will ensure performance tracking and measurable improvements. This basin retrofit represents a critical step in a coordinated, science-based approach to restoring ecological health and water quality in New Jersey’s largest lake.


3. Cozy Lake, Jefferson Township – Addressing Emerging Contaminants

Jefferson Township received $350K in grant funding to develop an Emerging Contaminants Management Plan for Cozy Lake, focusing on cyanotoxins and HABs. Cozy Lake is a 28-acre waterbody within a 1,152-acre sub-watershed that includes both forested (60%) and developed (29%) land. The lake is fed by the Rockaway River at its northern end and a smaller southeastern inlet, with outflow through a dam on the western edge.

The shoreline is primarily residential lawn with minimal emergent wetlands, and several inlets and rock-lined drainage ditches exhibit erosion and lack slope protection, contributing to sediment loading. Princeton Hydro provided early technical input to shape this innovative project with the creation of a comprehensive Jefferson Township Lake and Watershed Restoration and Protection Plan. As part of the plan, Princeton Hydro made recommendations for Cozy Lake, which included enhancing shoreline buffers with native vegetation and installing living shorelines at select properties to stabilize soils, filter stormwater and reduce nutrient loading, improve habitat quality, and enhance community access. These measures, combined with in-lake monitoring and proactive management strategies, will help mitigate HABs and protect ecological and public health.


4. Rockaway Township – Watershed-Based Green Infrastructure

Rockaway Township received $399K in grant funding to implement elements of its Watershed Implementation Plan, focusing on green infrastructure stormwater management and nutrient reduction to improve water quality. The project will retrofit the municipal complex by converting a rock-lined drainage swale into a vegetated swale with a bioretention basin, designed to filter stormwater runoff and reduce nonpoint source pollutants entering Fox’s Pond and Fox Brook.

Princeton Hydro played a key role in developing the Watershed Implementation Plan, which encompasses 11 private lakes within the Rockaway River watershed, prioritizing critical locations for intervention and designing cost-effective green infrastructure BMPs. This regional approach aligns with strategies recommended by NJDEP and the Highlands Council. The plan included a comprehensive watershed-based assessment to identify and quantify factors contributing to eutrophication, evaluate management measures, estimate costs, and establish an implementation schedule. Princeton Hydro authored the final report, which guided the Township in applying for the Section 319(h) grant and now informs the design and construction of green stormwater infrastructure that will deliver measurable water quality improvements while supporting ecological restoration goals.


5. Green Trust Alliance – Green Infrastructure and Community Engagement

Green Trust Alliance (GTA), a nationally accredited land trust and public charity dedicated to accelerating large-scale conservation, received $1.39 million in NJDEP funding to implement green infrastructure improvements at Pinelands Regional High School in Tuckerton, New Jersey. This initiative targets the Tuckerton Creek watershed, which drains into Tuckerton Creek and ultimately flows into Barnegat Bay—a critical estuary spanning 33 municipalities in Ocean County and four in Monmouth County. The retrofit will transform the school’s stormwater detention basin into a multi-functional system that mimics natural hydrology, enhances flow control, and improves water quality locally and in the larger Barnegat Bay watershed.

Working with GTA and GreenVest, Princeton Hydro is serving as the design engineer, applying nature-based engineering and ecological restoration techniques to intercept, evapotranspire, and infiltrate stormwater runoff at its source. In addition to its technical objectives, the effort includes a strong community engagement component and an educational platform for students. By bringing green infrastructure into the school environment, the initiative provides hands-on experience with water resources, stormwater management, and ecological engineering, help to build STEM skills while fostering a deeper connection to the surrounding landscape and an understanding of how natural systems work together to support environmental and community health.


Princeton Hydro also assisted several of these partners in developing successful NJDEP Section 319(h) grant applications, providing technical documentation, conceptual designs, and pollutant load reduction estimates to strengthen the proposals.

To date, the Murphy Administration has awarded more than $33M in Water Quality Restoration grants to improve the health of waterways in all corners of the state. Click here to read about all the 2025 grant funding recipients and their innovative projects.

As NJDEP Environmental Protection Commissioner Shawn M. LaTourette noted in the department's press release, “Enhancing the ecological health of our lakes, rivers, streams and coastal waters has long been a priority of the Murphy Administration. The Department of Environmental Protection is pleased to award these grants that will help our partners advance a variety of strategies to improve the health of these waterways and enhance the quality of life in our communities.”

We are proud to play a continued role in advancing that mission: helping communities implement practical, data-driven solutions that make a measurable difference for New Jersey’s waterways and the people who depend on them. Click here to learn more about our work to protect natural habitat and restore water quality throughout the New Jersey.

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We are thrilled to announce that Dr. Fred Lubnow, Senior Technical Director of Ecological Services at Princeton Hydro, has been honored with the prestigious Peter Homack Award by the American Water Resources Association, New Jersey Section (NJ-AWRA). The award was presented during NJ-AWRA’s annual meeting in December, recognizing Fred’s outstanding contributions to the multi-disciplinary understanding and management of New Jersey’s water resources.

The Peter Homack Award, established in 1987, commemorates the late Peter Homack, a former NJ-AWRA president and distinguished New Jersey engineer. The award celebrates individuals who exemplify Homack’s legacy of advancing water resource management through collaboration and innovation.

Fred’s selection for this honor is a testament to his decades-long dedication to the restoration and protection of water resources. Since Princeton Hydro’s founding in 1998, Fred has played a pivotal role in the study and restoration of hundreds of lakes across New Jersey and the Mid-Atlantic region. His work at Lake Hopatcong, in particular, stands as a shining example of his commitment. For over 30 years, Fred has partnered with Lake Hopatcong stakeholders to implement comprehensive restoration plans, develop best management practices, and achieve milestones toward the lake’s water quality goals.

Beyond his work at Princeton Hydro, Fred has enriched the field of water resource management through education and stewardship. He teaches watershed management at Delaware Valley University and freshwater ecology at Villanova University, inspiring the next generation of environmental stewards. Fred has contributed to NJ-ARWA over the last five years through a variety of presentations on harmful algal blooms (HABs) and watershed planning. Additionally, he has held leadership roles in the North American Lake Management Society (NALMS) and the Pennsylvania Lake Management Society. Selected as a member of the New Jersey Department of Environmental Protection’s HAB Expert Team, Fred has been instrumental in shaping the HAB advisory and alert systems we rely on today. His contributions have advanced our understanding of the factors driving cyanobacterial blooms in New Jersey’s lakes, offering valuable insights to improve the prediction, prevention, and management of these blooms.

Although Fred could not attend the award ceremony in person, he joined virtually via Zoom as his colleague Michael Hartshorne, Princeton Hydro’s Director of Aquatics, accepted the award on his behalf. During Michael's acceptance speech, he said:

“I’ve worked with Fred since I started at Princeton Hydro in 2006. He’s a humble leader, a dedicated mentor, and an overall fantastic person. Fred’s enthusiasm for lake ecology, particularly algae, is truly infectious. It’s a rare skill to make others genuinely excited about such a niche topic, but Fred has a remarkable way of doing just that. Fred truly embodies the spirit of the Peter Homack Award, and it’s an honor to receive this on his behalf.”

Fred’s passion, expertise, and collaborative spirit have left an indelible mark on water resource management in New Jersey and beyond. Princeton Hydro congratulates him on this well-deserved recognition and looks forward to his continued contributions to the field.

Earlier this year, Fred wrote a piece on "Preparing for Potential Harmful Algal Blooms: An Urgent Call to Action for NJ’s Lakes and Reservoirs." Click here to read it and learn more about his work to address the challenges posed by HABs and protect the integrity of our water bodies. [gallery link="none" ids="16058,4919,2956"] [post_title] => Princeton Hydro’s Dr. Fred Lubnow Receives NJ-AWRA's Peter Homack Award [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => princeton-hydros-dr-fred-lubnow-receives-nj-awras-peter-homack-award [to_ping] => [pinged] => [post_modified] => 2025-03-26 23:50:52 [post_modified_gmt] => 2025-03-26 23:50:52 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=16054 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [2] => WP_Post Object ( [ID] => 13355 [post_author] => 1 [post_date] => 2023-08-16 07:03:24 [post_date_gmt] => 2023-08-16 07:03:24 [post_content] =>

400 native plants were installed along the western shoreline of Memorial Pond in Mount Arlington, New Jersey. The planting was completed in one day by a team of 20+ volunteers, staff members from Mt. Arlington Department of Public Works (DPW), Lake Hopatcong Foundation, Lake Hopatcong Commission, Princeton Hydro, and a generous community member who volunteered his excavating equipment (and time).

The planting initiative aims to prevent shoreline erosion, promote the growth of native species, increase wildlife habitat, and improve the water quality of Memorial Pond and Lake Hopatcong. Funding for this project was secured through a grant from the New Jersey Department of Environmental Protection, awarded to the Lake Hopatcong Commission in partnership with the Lake Hopatcong Foundation.

[caption id="attachment_13422" align="aligncenter" width="616"] Photo by Lake Hopatcong Foundation Executive Director Kyle Richter[/caption]

Memorial Pond

Drainage Area Aerial Map of Mt. Arlington Memorial Beach and Memorial Park in New Jersey. Created by Princeton Hydro.Memorial Pond is a 0.3-acre stormwater runoff basin that gradually releases into Glen Brook, which then flows into Lake Hopatcong. The pond receives sheet flow of stormwater from the adjacent road, which contributes to nutrient and sediment loading, thus locally reducing water quality in Memorial Pond and ultimately the waters of Lake Hopatcong.

Memorial Park, which includes Memorial Pond and Glen Brook, was identified by Princeton Hydro and the Lake Hopatcong team as a priority site for improvement, targeting initiatives that reduce pollutants and excessive nutrients entering into Lake Hopatcong.

Additionally, the pond’s steeply-sloped shoreline was bare and only stabilized with large rocks at the base of the banks. In the absence of stabilizing vegetation, the pond’s banks were experiencing erosion, and there was some concern about a few mature trees along the shoreline potentially falling into the pond.

[gallery link="none" ids="13416,13407,13413"]

The photos above were taken in April 2023 before the planting initiative.


Shoreline Planting Initiative

The plant selection and layout were designed taking into account the steep slope and presence of mature, existing trees as well as focusing on regionally native plant species that will thrive and help stabilize the eroding shoreline. The planting team, led by Princeton Hydro Landscape Architect Jamie Feinstein, RLA and Aquatics Project Manager Pat Rose, was given precise instructions on how to install the plants to eliminate washouts and ensure the root systems can embrace the soil and hold it in place.

A variety of native herbaceous plants and shrubs were chosen for the site, including pennsylvania sedge, slender mountain mint, blue flag iris, sweet azalea, smooth hydrangea, and maple-leaved viburnum.

[gallery link="none" ids="13427,13421,13428"]

The plants will help reduce stormwater flow, absorb excess nutrients, prevent erosion, and ultimately decrease sedimentation to the pond, while creating a visually pleasing addition to the park and providing a habitat for pollinators and birds. Overall, this project promotes a healthier and more balanced ecosystem in Memorial Park.

[gallery link="none" ids="13400,13392,13394"]

The photos above were taken in July 2023 immediately after the planting initiative.


Multi-Faceted Approach to Water Quality Improvements

The installation of these beneficial plants is part of a series of water quality initiatives on Lake Hopatcong funded by a NJDEP Freshwater Harmful Algal Bloom (HAB) Prevention & Management Grant and 319(h) Grant awarded to Lake Hopatcong Commission in partnership with the Lake Hopatcong Foundation.

Additional initiatives included in the watershed implementation and HABs management plan are, the installation of:

  • floating wetland island (FWI), which are a low-cost, effective green infrastructure solution designed to mimic natural wetlands in a sustainable, efficient, and powerful way. FWIs improve water quality by assimilating and removing excess nutrients; 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;

  • biochar filtration bags, which improve water quality by removing phosphorus from waterbodies. Biochar can be placed in floatation balls, cages, or sacks, which are then tethered along the shoreline and in critical locations throughout the waterbody; and

  • nanobubble aeration system, which increases the concentrations of dissolved oxygen in the water, prevents stagnation of water, increases circulation, disrupts thermal stratification which provides “through-column” mixing, and minimizes the occurrence of HABs.

“Paired with biochar filters attached to buoys in the pond and continued monitoring and maintenance of the plantings by the DPW, these steps will set a healthy precedent for what can be achieved through working together with funders, local partners, science, and landscape architecture,” said Feinstein, who sourced plant material, provided logistics and co-led the planning and volunteer planting event along with Rose.

Princeton Hydro's Landscape Architect, Cory Speroff PLA, ASLA, CBLP, designed the planting plan, and Will Kelleher and Jackson Tilves from the Aquatics Team participated in the plant installation event with Feinstein.

Princeton Hydro is also authoring and supplying a maintenance manual that provides guidance on seasonal care of the plantings, when to remove the herbivory protection fencing, pruning, watering, and other activities that support the long term success of the planting initiative. 

“This collaborative effort to enhance water quality serves as a prime example of how seemingly simple actions can have a meaningful impact on safeguarding our water resources for the benefit of future generations,” said the Lake Hopatcong Foundation.

[gallery link="none" ids="13403,13429,13393"]

The photos above from left to right: June 2023 before the planting; July 2023 during the planting (photo by Lake Hopatcong Foundation Executive Director Kyle Richter); and July 2023 immediately after the planting.


Princeton Hydro has been working on Lake Hopatcong, New Jersey’s largest Lake, for 30+ years, restoring the lake, managing the watershed, reducing pollutant loading, and addressing invasive aquatic plants and nuisance algal blooms. To read about some of the other projects we’ve recently worked on at Lake Hopatcong, click here.

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This article, written by Princeton Hydro team members, was recently published in the ANJEC Report, a quarterly magazine published by the Association of New Jersey Environmental Commissions.

Our lakes in New Jersey are an invaluable resource for clean drinking water, outdoor recreation, and agriculture and provide habitat for aquatic flora and fauna. Home to about 1,700 lakes, the “Garden State” is also the most densely populated state. Excess nutrients from fertilizers, roadway pollutants, overdevelopment, and failing septic systems can end up in our lakes and impair water quality. Larger rain events can also cause erosion and instability of streams, adding to the influx of more excess nutrients to our lakes and ponds. Changes in hydrology, water chemistry, biology, and/or physical properties in these complex ecosystems can have cascading consequences that can alter water quality and the surrounding ecosystem. For example, excess nutrients can fuel algal and plant growth in lakes and lead to issues like harmful algal blooms (HABs) or fish kills.

In order to ensure that we protect the overall health of our local waterbodies, it’s important that we look beyond just the lake itself. Implementing holistic watershed-based planning is a critical step in managing stormwater runoff, preventing the spread of HABs, and maintaining water quality. A watershed management plan defines and addresses existing or future water quality problems from both point sources and nonpoint sources of pollutants*. This approach addresses all the beneficial uses of a waterbody, the criteria needed to protect the use, and the strategies required to restore water quality or prevent degradation. When developing a watershed plan, we review all the tools in the toolbox and recommend a variety of best management practices to prevent nutrients from entering lakes or streams. Options include short- and long-term solutions such as green stormwater infrastructure, stream bank stabilization, and stormwater basin retrofits.

To reduce nutrient availability in lakes, one innovative tool in our toolbox is floating wetland islands (FWIs). FWIs are a low-cost, effective green infrastructure solution that are designed to mimic natural wetlands in a sustainable, efficient, and powerful way. They improve water quality by assimilating and removing excess nutrients; 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. FWIs are also highly effective in a range of waterbodies from big to small, from deep to shallow.

[caption id="attachment_4363" align="aligncenter" width="631"]This illustration, created by Staff Scientist Ivy Babson, conveys the functionality of a Floating Wetland Island This illustration, sketched by Princeton Hydro Staff Scientist Ivy Babson, conveys the functionality of a floating wetland island.[/caption]  

Typically, FWIs consist of a constructed floating mat, usually composed of woven, recycled plastic material, with vegetation planted directly into the material. The islands are then launched into the lake and anchored in place, and, once established, require very little maintenance.

It estimated that one 250-square-foot FWI has a surface area equal to approximately one acre of natural wetland. These floating ecosystems can remove approximately 10 pounds of phosphorus each year. To put that into perspective, one pound of phosphorus can produce 1,100 pounds of algae each year, so each 250-square-feet of FWI can potentially mitigate up to 11,000 pounds of algae.

In addition to removing phosphorus that can feed nuisance aquatic plant growth and algae, FWIs also provide excellent refuge habitat for beneficial forage fish and can provide protection from shoreline erosion.

Let's take a look at some examples of FWIs in action:

Lake Hopatcong

[gallery columns="2" link="none" ids="11071,10666"]  

Princeton Hydro has been working with Lake Hopatcong, New Jersey’s largest Lake, for 30+ years, restoring the lake, managing the watershed, reducing pollutant loading, and addressing invasive aquatic plants and nuisance algal blooms. Back in 2012, Lake Hopatcong became the first public lake in New Jersey to install FWIs. In the summer of 2022, nine more FWIs were installed in the lake with help from staff and volunteers from the Lake Hopatcong Foundation, Lake Hopatcong Commission, and Princeton Hydro. The lake’s Landing Channel and Ashley Cove were chosen for the installations because they are both fairly shallow and prone to weed growth. The installation of these floating wetland islands is part of a series of water quality initiatives on Lake Hopatcong funded by a NJDEP Harmful Algal Bloom Grant and 319(h) Grant awarded to Lake Hopatcong Commission and Lake Hopatcong Foundation.


Greenwood Lake

floating wetland island installation on greenwood lake in new jersey

Princeton Hydro partnered with the Greenwood Lake Commission (GWLC) on a FWI installation in Belcher's Creek, the main tributary of Greenwood Lake. The lake, a 1,920-acre waterbody located in both New Jersey and New York, is a highly valued ecological, economical, and recreational resource. The lake also 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 with drinking water.

The goal of the FWI Installation was to help decrease total phosphorus loading, improve water quality, and create important habitat for beneficial aquatic, insect, bird, and wildlife species. The project was partially funded by the NJDEP Water Quality Restoration Grants for Nonpoint Source Pollution Program under Section 319(h) of the federal Clean Water Act. GWLC was awarded one of NJDEP’s matching grants, which provided $2 in funding for every $1 invested by the grant applicant.


Harveys Lake

Volunteers install native plants in one of the FWIs installed in Harveys Lake. Photo by: Mark Moran, The Citizen’s Voice.

Measuring 630+ acres, Harveys Lake is the largest natural lake (by volume) in 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 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. 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. The FWIs were funded by PADEP.


Wesley Lake and Sunset Lake

Working with the Deal Lake Commission (DLC), Princeton Hydro designed and installed 12 floating wetland islands at two lakes in Asbury Park, NJ. In order to complete the installation of the floating wetland islands, our team worked with the DLC to train and assist over 30 volunteers to plant plugs in the islands and launch them into the two lakes. Our experts helped disseminate knowledge to the volunteers, not only about how to install the floating wetland islands, but how they scientifically worked to remove excess nutrients from the water. With assistance from Princeton Hydro, DLC acquired the 12 floating islands – six for Wesley Lake and six for Sunset Lake – through a Clean Water Act Section 319(h) grant awarded by NJDEP.


In addition to the direct environmental benefits of FWIs, the planting events themselves, which usually involve individuals from the local lake communities, have long-lasting positive impacts. 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.

For more information on watershed planning or installing FWI in your community, click here to contact us. To learn more about ANJEC, go here.

- *U.S. Environmental Protection Agency. 2008. Handbook for Developing Watershed Plans to Restore and Protect Our Waters.

[post_title] => Floating Wetland Islands: An Effective, Affordable, and Sustainable Lake Management Tool [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => floating-wetland-islands-anjec-2023 [to_ping] => [pinged] => [post_modified] => 2023-08-14 10:41:41 [post_modified_gmt] => 2023-08-14 10:41:41 [post_content_filtered] => [post_parent] => 0 [guid] => https://princetonhydro.com/?p=12609 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 0 [filter] => raw ) [4] => WP_Post Object ( [ID] => 12419 [post_author] => 1 [post_date] => 2023-03-17 18:44:47 [post_date_gmt] => 2023-03-17 18:44:47 [post_content] => [caption id="attachment_12423" align="aligncenter" width="901"] Harveys Lake, Luzerne County, PA in February 2023 (Photo by Jason Miller)[/caption]   By Dr. Fred Lubnow, Senior Technical Director of Ecological Services

The Winter of 2022 – 2023 is turning out to be a mild one, at least in the Mid-Atlantic region of the United States. Anecdotally, there has been no measurable amount of snowfall in 2023 as of early March. In northeastern Pennsylvania, January and February 2023 mean monthly temperatures were 9.6 and 7.5 degrees warmer relative to their long-term respective average values. In northern New Jersey, January and February 2023 mean monthly temperatures were 11.9 and 5.6 degrees warmer relative to their respective long-term average values (Northeast Regional Climate Center CLIMOD database).

[caption id="attachment_12421" align="alignleft" width="239"] Lake Hopatcong, Sussex – Morris Counties, NJ (Photo by Donna Macalle-Holly, Lake Hopatcong Foundation)[/caption]

This has had a profound impact on lake ecosystems. For example, in early 2023, both Harveys Lake (Luzerne County, PA) and Lake Hopatcong (Morris and Sussex Counties, NJ) have had no lake-wide ice cover. While measurable amounts of both snowfall and ice cover are still possible in the remaining weeks of March, it highly unlikely that such conditions would persist for weeks. Such ice-free conditions on our lakes, ponds and reservoirs will certainly have a profound impact on these ecosystems as we move into the 2023 growing season.

Algae May Grow Earlier in the Season

Undoubtably, current conditions are at a minimum partially attributed to climate change and will have a direct impact on the upcoming 2023 growing season. In the absence of ice, and more importantly snow-cover over the ice, aquatic plants and algae can begin to grow earlier in the season. Some plants, such as the invasive species curly-leaved pondweed (Potamogeton crispus), prefer cooler temperatures and tend to attain their highest densities in the spring and early summer. However, under such ice-free conditions, we have seen curly-leaved pondweed growing along the bottom of New Jersey lakes as early as February. This can result in more nuisance plant densities earlier in the year.

While most cyanobacteria, the group of algae known to have the potential to produce cyanotoxins, tend to attain their maximum growth and biomass over the hot summer months, there are several genera that are more tolerant of cool temperatures. For example, one filamentous genus, Aphanizomenon, is one of the first cyanobacteria to appear in the plankton in the spring. Indeed, over the last few years Aphanizomenon has been appearing earlier in the year and at higher densities in many of the lakes monitored and managed by Princeton Hydro. Another cyanobacteria known to bloom in cooler waters is Coelosphaerium. Coupled with slightly warmer temperatures over the late winter and early spring, cyanobacteria blooms could become more common and larger in magnitude, earlier in the year. Such blooms are frequently called Harmful Algal Blooms (HABs).

Many cyanobacteria produce resting spores called akinetes during conditions of environmental stress, such as colder temperatures and desiccation. These akinetes settle to the bottom and are re-activated as water temperatures increase. Warmer late winter and early spring temperatures, particular over the sediments, could mean more akinetes actively growing into vegetative cells earlier in the growing season.

Milder Winters Could Lead to New Invasive Species

[caption id="attachment_12439" align="alignright" width="476"] At a lake in Somerset County on March 7, 2023, Spirogyra (a green mat algae that prefers cold waters) is present and curly-leaved pondweed is already growing and well established. Photo by Princeton Hydro.[/caption]

Last year (2022), was the first time that the cyanobacteria Cylindrospermopsis was identified in Lake Hopatcong. In fact, this genus was the most abundant cyanobacteria in Lake Hopatcong during our July and August sampling events, but was no longer found by the early October sampling event. The Cylindrospermopsis found in Lake Hopatcong may be an invasive species that historically has been found in tropic and subtropic waterbodies. However, over the years, this cyanobacterium has been found in temperate waterbodies. Milder and warmer winters may mean more invasive species such as Cylindrospermopsis appearing in Mid-Atlantic waterbodies.

What Should You Do?

In the absence of ice and snow-cover to put the sediments in the dark and prevent photosynthesis, coupled with warmer temperatures in the late winter and early spring, may lead to more aquatic plant and algal growth earlier in the year. So what should be done about this?

1. Sample Early: March or April

First, we recommend initiating sampling earlier in the year, sometime in March or April; do not wait until May to begin sampling. Second, in addition to sampling the surface waters, sampling should also be conducted in near-shore areas, immediately above sediments and at the sediment-water interface. Samples should be examined under the microscope for the presence of akinetes and/or inactive colonies of cyanobacteria. Third, near-shore areas should also be surveyed for the presence of submerged, aquatic plants, in particular invasive species such as curly-leaved pondweed or hydrilla.

2. Encourage Residents to Reduce Nutrients Entering the Waterway

Finally, while most climate models indicate that HABs will more than likely increase in warmer conditions, the magnitude of this response will be strongly dependent on the availability of nutrients, in particular phosphorus. While phosphorus will drive the growth of cyanobacteria, the availability of external sources of nitrogen can increase the probability of a HAB producing cyanotoxins such as microcystins, which is a nitrogen “heavy” molecule.

Thus, if colonies of cyanobacteria or akinetes are found in the sediments over the spring, the lake community and stakeholders should be informed and efforts should be implemented to reduce the availability of nutrients such as using non-phosphorus fertilizers, picking up pet wastes, goose management, routine pump-outs of septic systems once every three years, where possible stabilize exposed soil by planting native vegetation and consider the use of green infrastructure such as rain gardens. By letting the community know that cyanobacteria may be lurking on the sediments over the spring season, it may mobilize efforts to implement both in-lake and watershed measures to minimize the potential development of HABs.


Princeton Hydro provides pond and lake management and monitoring services to hundreds of waterbodies in the Northeast.  If you would like to learn more about our services for your community, please send us a message through our website.

Dr. Fred Lubnow, Princeton Hydro's Senior Technical Director, Ecological Services, is an expert in aquatic and watershed management, restoration ecology, community and ecosystem ecology, and the use of benthic macroinvertebrate and fish in-stream bioassessment protocols. Dr. Lubnow has managed hundreds of lake projects and provides technical expertise for a variety of lake and watershed restoration projects.

His experience in lake and reservoir restoration includes the design and implementation of dredging, aeration, chemical control of nuisance species, nutrient inactivation (i.e. alum) and biomanipulation. His experience in watershed restoration includes the design and implementation of structural Best Management Practices (BMPs), the development of Total Maximum Daily Load (TMDL) pollutant budgets, and the design, implementation and analysis of watershed-based monitoring programs.

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When monitoring and managing the health of a lake or pond, dissolved oxygen is one of the most important indicators of water quality. Dissolved oxygen refers to the level of free, non-compound oxygen present in water. It is an important parameter in assessing water quality because of its influence on the organisms living within a body of water; the vast majority of aquatic life needs sufficient amounts of oxygen dissolved in water in order to survive.

Pollutants, the decomposition of invasive aquatic weed growth, and algae blooms significantly reduce dissolved oxygen. The purpose of aeration in lake management is to increase the concentrations of dissolved oxygen in the water. Aeration systems achieve these water quality improvements by helping prevent stagnation of water, increasing circulation, disrupting thermal stratification which provides “through-column” mixing, and minimizes the occurrence of harmful algal blooms (HABs).

Princeton Hydro has been working with the Lake Hopatcong Commission and Lake Hopatcong Foundation to implement several projects aimed at reducing the impacts of HABs in Lake Hopatcong, including the installation of three innovative aeration systems in different areas of the lake. Funding for these projects have come from a NJ Department of Environmental Protection Water Quality Restoration HAB grant awarded to the Commission in 2020, with additional funding and support coming from the Foundation, Morris and Sussex Counties, and four municipalities that surround Lake Hopatcong.


Air Curtain Aeration System

Our team completed the installation of an air curtain system at Shore Hills Country Club in Roxbury Township in early November 2020. The system produces a wall of bubbles that provide the kinetic energy to push and deflect away floating cyanobacteria and other toxins trying to enter the waterway. Installed near the shoreline, the air curtain increases the movement of the water, making it more difficult for floating debris, pollutants, and HABs to accumulate near the shore and in nearby shallow water areas.


Nanobubble Aeration System

Image by: Nanobubble Systems

Nanobubbles are extremely small gas bubbles that have several unique physical properties that make them very different from normal bubbles. Nanobubble aerators directly saturate the water with significantly more oxygen than traditional water aeration systems. These systems produce ultra-fine bubbles that are nearly invisible to the human eye. Unlike “traditional” aeration systems that push air bubbles to the surface in order to circulate the water and increase the dissolved oxygen levels, nanobubbles are so small that they remain within the water column for an extended period of time, directly oxygenating the water. Our team is scheduled to complete a nanobubble system install for Lake Hopatcong in the Spring of 2021.


Nanobubble Aeration System with Ozone

At Lake Hopatcong’s Lake Forest Yacht Club in Jefferson Township, our team installed a Nanobubble System with Ozone, which was completed in November 2020. This system generates ultrafine microbubbles (nanobubbles) containing ozone, which is used to disinfect water supplies and works to break down organic material in the water. These nanobubbles harness the unique biocidal power of ozone and place it into a safe delivery mechanism that is highly effective but also ensures human and environmental safety. The resulting ozone nanobubbles eliminate a wide range of polluting chemicals as well as herbicides, pesticides, and microbial toxins, which are all known causes of HABs.

The nanobubble technology is a relatively new strategy for preventing cyanobacteria blooms. Evaluation of the air curtain and both nanobubble systems in controlling and minimizing HABs in Lake Hopatcong will begin in Spring 2021. Our team will closely monitor the effectiveness throughout the 2021 season and provide detailed reports of our findings. Stay tuned for more info!


Increasing the dissolved oxygen levels in a pond or lake provides many benefits including improved water quality, healthier fish and plants, more efficient filtration, and reduced nuisance algae growth. To learn more about Princeton Hydro's collaborative efforts to protect our valuable water resources, click here.

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The use of biochar, a pure carbon, charcoal-like substance made from organic material, to enhance soil fertility is thought to have originated over 2,000 years ago in the Brazilian Amazon. Archeological studies indicate populations of native Amazonians used biochar to amend nutrient-poor soils to increase agricultural productivity.

Biochar is generally produced through a process called pyrolysis. Pyrolysis is the decomposition of organic matter brought about by high temperatures (typically 800°F) in an environment with limited oxygen. The word pyrolysis is coined from the Greek-derived elements pyro "fire" and lysis "separating."

Recently, biochar has received tremendous attention and its usage has moved beyond traditional agricultural and landscaping soil amendment applications. It is being championed as a useful technique for soil restoration, carbon sequestration, and - the one we’re most excited about - water quality management.

Photo by: Colleen Lyons of the Lake Hopatcong Commission
Photo by: Colleen Lyons of the Lake Hopatcong Commission

That’s right! Biochar has been shown to improve water quality by removing nutrients from waterbodies. Biochar can be placed in floatation balls, cages, or sacks, which are then tethered along the shoreline and in critical locations throughout the waterbody, like where an inlet enters a lake. The benefits of biochar far outweigh the relatively low-cost investment.

Photo by: Colleen Lyons of the Lake Hopatcong Commission
Photo by: Colleen Lyons of the Lake Hopatcong Commission

Princeton Hydro recently installed biochar flotation bags in various locations throughout Lake Hopatcong, including the Lake Winona outlet, the Lake Forest Yacht Club inlet, Lakeside Avenue and Holiday Avenue inlet in Hopatcong, and the Edith Decker School outlet in Mount Arlington. The biochar bag installation, which was funded by the NJDEP Freshwater HABs Prevention & Management Grant provided to the Lake Hopatcong Commission (LHC) and its project partner the Lake Hopatcong Foundation (LHF), is one part of a multi-pronged lake management plan to protect the overall water quality of Lake Hopatcong.

Last summer, Lake Hopatcong - along with freshwater lakes throughout the country - was hit hard by a HAB outbreak that caused beach closures, health advisories, and water quality degradation. Princeton Hyrdo has been working with the LHC, LHF, Morris & Sussex Countys, and local municipalities to implement a number of lake management strategies. For example, Floating Wetland Islands, which use a mix of microbes and native plants to remove excess algae-causing nutrients from the water, were installed throughout Lake Hopatcong.


Over the coming weeks, our team is installing more biochar bags in Roxbury, NJ at Duck Pond and in Mount Arlington, NJ at Memorial Pond. Stay tuned for more info! To learn more about our water quality management services, go here: princetonhydro.com/pond&lake.

 

[post_title] => Using an Ancient Technology in a New Way: Removing Nutrients in a Lake with Biochar [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => biochar [to_ping] => [pinged] => [post_modified] => 2026-03-03 14:59:42 [post_modified_gmt] => 2026-03-03 14:59:42 [post_content_filtered] => [post_parent] => 0 [guid] => https://www.princetonhydro.com/blog/?p=5242 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 6 [filter] => raw ) [7] => WP_Post Object ( [ID] => 1615 [post_author] => 3 [post_date] => 2020-03-20 12:14:14 [post_date_gmt] => 2020-03-20 12:14:14 [post_content] => Photo from: New York State Department of Environmental Conservation, water chestnut bed at Beacon Spring is officially here! Tulips will soon be emerging from the ground, buds blossoming on trees and, unfortunately, invasive plant species will begin their annual growing cycle. No type of habitat or region of the globe is immune to the threat of invasive species (“invasives”). Invasives create major impacts on ecosystems throughout the world, and freshwater ecosystems and estuaries are especially vulnerable because the establishment of such species in these habitats is difficult to contain and reverse. This blog provides an introduction to invasive aquatic species, including information that will help you prevent the spread of invasives in the waterways of your community.
Defining Invasive Species
Invasive species can be defined as non-native occurring in an ecosystem that is outside its actual natural or native distributional range. Although the colonization of an ecosystem by non-native species can occur naturally, it is more often a function of human intervention, both deliberate and accidental. For aquatic ecosystems some species have become established as a result of the aquarium trade, fish culture practices and/or transport of plants and animals in the bilge and ballast water of trans-oceanic shipping vessels. One of the primary reasons invasives are able to thrive, spread rapidly, and outcompete native species is that the environmental checks and predators that control these species in their natural settings are lacking in the ecosystems and habitat in which they become introduced. The subsequent damages they cause occur on many ecological levels including competition for food or habitat (feeding, refuge and/or spawning), direct predation and consumption of native species, introduction of disease or parasites, and other forms of disruption that lead to the replacement of the native species with the invasive species. As a result, invasives very often cause serious harm to the environment, the economy, and even human health. A prominent example is the Emerald Ash Borer, a non-native, invasive beetle that is responsible for the widespread death of ash trees. As noted above, there are a large number of aquatic invasive species. Some of the more commonly occurring non-native aquatic plant species that impact East Coast lakes, ponds and reservoirs include:
Understanding How Invasives Spread
Either intentionally or unintentionally, people have helped spread invasives around the globe. This is not a recent phenomenon but rather something that has been occurring for centuries. “Intentional introductions,” the deliberate transfer of nuisance species into a new environment, can involve a person pouring their home aquarium into a lake or deliberate actions intended to improve the conditions for various human activities, for example, in agriculture, or to achieve aesthetics not naturally available. Photo by: Tom Britt/CC Flickr, zebra Mussels adhered to a boat propeller“Unintentional introductions” involve the accidental transfer of invasives, which can happen in many ways, including aquatic species attached to the hull of boats or contained in bilge and ballast water. A high-profile example is the introduction of zebra mussels to North America. Native to Central Asia and parts of Europe, zebra mussels accidentally arrived in the Great Lakes and Hudson River via cargo ships traveling between the regions. The occurrence, density, and distribution of Zebra mussels occurred at an alarming rate, with the species spreading to 20 states in the United States and to Ontario and Quebec in Canada. Due to their reproductive fecundity and filter-feeding ability, they are considered the most devastating aquatic invasive species to invade North American fresh waters. They alter and diminish the plankton communities of the lakes that they colonize leading to a number of cascading trophic impacts that have especially negative consequences on fisheries. Zebra mussel infestations have also been linked to increased cyanobacteria (bluegreen algae) blooms and the occurrence of harmful algae blooms (HABs) that impact drinking water quality, recreational use, and the health of humans, pets, and livestock. Additionally, higher than average temperatures and changes in rain and snow patterns caused by climate change further enable some invasive plant species to move into new areas. This is exemplified by the increased northly spread of hydrilla (Hydrilla verticillate), a tropical invasive plant species that has migrated since its introduction in Florida in the 1950s to lakes, rivers, and reservoirs throughout the U.S. Regardless of how any of these invasive species first became established, the thousands of terrestrial and aquatic invasive species introduced into the U.S. have caused major ecological, recreational and economic impacts.
Measuring the Impacts of Invasives
After habitat loss, invasive, non-native species are the second largest threat to biodiversity. According to The Nature Conservancy, “Invasive species have contributed directly to the decline of 42% of the threatened and endangered species in the United States. The annual cost to the nation’s economy is estimated at $120 billion a year, with over 100 million acres (an area roughly the size of California) suffering from invasive plant infestations. Invasive species are a global problem — with the annual cost of impacts and control efforts equaling 5% of the world’s economy.” Of the $120 billion, about $100 million per year is spent on aquatic invasive plant control to address such deleterious issues as:
  • Human health (West Nile Virus, Zika Virus)
  • Water quality impacts (Canada geese)
  • Potable water supplies (Zebra mussel)
  • Commercial fisheries (Snake head, lamprey, Eurasian ruffe, round goby)
  • Recreational activities (Eurasian watermilfoil, water chestnut, hydrilla)
  • Biodiversity (Purple loosestrife, common reed, Japanese knotweed)
Invasive species can change the food web in an ecosystem by destroying or replacing native food sources. As the National Wildlife Federation explains, “The invasive species may provide little to no food value for native wildlife. Invasive species can also alter the abundance or diversity of species that are important habitat for native wildlife. Additionally, some invasive species are capable of changing the conditions in an ecosystem, such as changing soil chemistry...”
Addressing Invasives
Our native biodiversity is an irreplaceable and valuable treasure. Through a combination of prevention, early detection, eradication, restoration, research and outreach, we can help protect our native heritage from damage by invasive species.
What Can We Do?
  • Reduce the spread
  • Routinely monitor
  • Document and report
  • Spread the word
Reducing the Spread:
The best way to fight invasive species is to prevent them from occurring in the first place. There are a variety of simple things each of us can do to help stop the introduction and spread of invasives.
  • Plant native plants on your property and remove any invasive plants. Before you plant anything, verify with your local nursery and check out this online resource for help in identifying invasive plants.
  • Thoroughly wash your gear and watercraft before and after your trip. Invasives come in many forms – plants, fungi and animals – and even those of microscopic size can cause major damage.
  • Don't release aquarium fish and plants, live bait or other exotic animals into the wild. If you plan to own an exotic pet, do your research to make sure you can commit to looking after it. Look into alternatives to live bait.
Monitoring:
Invasive plant monitoring is one of the most valuable site­-level activities people can support. Contact your local watershed organizations to inquire about watershed monitoring volunteer opportunities. For example, the Lake Hopatcong “Water Scouts” program was established to seek out and remove any instances of the invasive water chestnut species. If you are a lake or watershed manager, the best way to begin an invasive plant monitoring project is with an expert invasive plant survey to determine which invasives are most likely to be problematic in your watershed and identify the watershed’s most vulnerable areas. Contact us to learn more.
Documenting and Reporting:
It’s important to learn to identify invasive species in your area and report any sightings to your county extension agent or local land manager. For example, in New Jersey there is the Invasive Species Strike Team that tracks the spread of terrestrial and aquatic invasives and works with local communities in the management of these species. Additionally, consider developing a stewardship plan for your community to help preserve its natural resources. Princeton Hydro’s team of natural resource scientists can help you get the ball rolling by preparing stewardship plans focused on controlling invasive species and protecting the long-term health of open spaces, forests habitats, wetlands, and water-quality in your community.
Spreading the word:
Many people still don’t understand the serious implications of invasive species. Education is a crucial step in stopping the spread of invasives, which is why it’s so important to talk with your neighbors, friends and family about the hazards and ecological/economic impacts of invasive species. Also consider talking with your community lake or watershed manager about hosting an educational workshop where experts can share their knowledge about invasives specific to your area and how best to address them.   We encourage you to share this article and spread your invasive species knowledge so that together we can help stop the introduction and spread of invasive species.

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The fishery of a lake is an intrinsic, incredibly dynamic element of a lake system, and managing a lake’s fishery can be a very complex endeavor. There is actually a lot more to it than simply stocking game fish. Although there is no “one way” in fisheries management, there are key guidelines that can be followed to maximize the recreational potential of your lake’s fishery and increase the success of your fishery management and stocking efforts. Over the past two decades, Princeton Hydro has been working with lake, pond, and reservoir managers to help them to align water quality, fishery, and ecological goals.

Princeton Hydro’s Founder, Dr. Steve Souza, recently gave a presentation on fisheries management at the Spring Meeting of the New Jersey Coalition of Lake Associations (NJCOLA). We’ve compiled a few essential elements from his presentation and have made the complete presentation available for free download.

Let’s dive in!

Benefits of a Healthy Fishery

Recreational fishing is an outdoor activity that can be enjoyed by people of all ages. When children are introduced to fishing, it helps cultivate a connection to the environment, thereby promoting outdoor activity and environmental stewardship among today’s youth.

Anglers have always served as important advocates for the conservation of natural resources. The sale of fishing licenses financially supports wildlife habitat conservation and enhancement as well as the protection and improvement of water quality. This increases the ecological services and functions of lakes and adds to their societal and recreational benefits.

A healthy fishery can have significant positive impacts on water quality. In a balanced, healthy fishery the ratio of forage and game fish affects the entire food web, helping to maintain the proper balance of zooplankton and phytoplankton. The “top down” ecological control associated with a balanced fishery minimizes algae blooms, sustains good water clarity and stable water quality. However, when the fishery is out of balance, the water quality and overall ecological health of the lake often suffers.

Before You Stock, Know Your Lake and Start with a Baseline

Before you do any fish stocking, it’s best to conduct a fishery survey. A fishery survey provides the vital data needed to design a stocking and management plan.

A balanced lake fishery is dependent on good water quality, ample habitat, and the correct ratio of predator and prey fish species. A properly designed and implemented fishery survey generates the data needed to quantify the overall composition of the existing fish community (predator vs. prey), the make-up of the forage (food) base, and the density and robustness of the lake’s top piscivores (prized game fish).

The resulting data helps identify if your fishery is balanced, which fish to stock, and how many of each species to introduce. It will also provide the benchmarks needed to solidify your management goals and, later on, help determine if the goals are being met. To stay on track, we recommend that a comprehensive fishery survey be conducted once every three years. Be sure to use the correct types and combination of “active” and “passive” sampling gear and thoroughly sample both the open water and nearshore areas of the lake.

The survey should include the collection and analysis of water quality data, and the mapping of available habitat. Water column water quality “profiles” provide vital information pertaining to the lake’s thermal and dissolved oxygen properties; key factors for a healthy, vibrant fishery. Here are some basic water quality guidelines:

  • Dissolved oxygen: ? 4 mg/L with 6-7 mg/L being ideal
  • For warm water fishery: Uniform temperatures at all depth (minimal or no thermal stratification)
  • For cold water fishery: Deep water temperature of 15 C, and dissolved oxygen ? 5 mg/L
  • pH: 6 to 8
  • Clarity: ? 3 feet (1 meter) Secchi disc transparency
  • Total Phosphorus: < 0.05 mg/L
  • Chlorophyll a: < 20 µg/L

Water quality sampling should also include an assessment of the lake’s zooplankton and phytoplankton communities, the base of your lake’s food web.

[caption id="attachment_1378" align="alignright" width="236"]  [/caption]

During the survey, take the time to quantify and map the distribution of existing forage, spawning, and refuge habitat. Lack of adequate habitat can significantly impede the fishery’s sustainability. This begins with the bathymetric mapping of the lake, which is basically an underwater survey of the bottom of the lake. This mapping shows where and how much shallow water versus open water habitat exists.  It can also help identify the location and distribution of important habitat types, such as shoals, rock piles, sandy open areas and natural structures (tree falls and snags). The data also helps determine where to create and introduce habitat, which can be in the form of brush piles, floating wetland islands, and other types of features that increase the spawning, recruitment, and foraging success of the fishery.

Stocking Your Lake

Once the fishery survey is completed, habitat is mapped and water quality analyzed, stocking can begin. In order to determine the specific stocking levels and rates that are right for your waterbody, here are some factors to consider:

  • Ensure your stocking efforts create or augment the correct ratio of predator (game) and prey (forage) fish.

  • Stock cautiously, focusing on a simple composition of predator and prey species. For most warm water lakes, largemouth bass should serve as the top predator and fathead minnow should be the primary prey.

  • Avoid problem fish, such as golden shiner, alewife and brown/black bullhead. Although these fish are often promoted as suitable forage species, they can be easily get overstocked and cause major disruptions of the fishery and to the degradation of water quality.

Go here for a more in-depth look at how to properly stock your fishery.

In Summary

A healthy sustainable fishery isn’t only a function of the types and amounts of fish stocked in a lake; it is directly a function of water quality, the availability and quality of spawning, foraging and refuge habitat, the ratio of forage to predator fish, and the overall composition and balance of the food web.

Begin with a fishery survey; the resulting data enables a correctly planned and implemented stocking program. Conduct routine surveys to assess the status of the fishery and the success of the program. Also, annual water quality testing provides the information needed to make wise pro-active fishery management decisions. It will also provide insights into the lake’s environmental conditions to ensure they are supportive of a healthy, productive and sustainable recreational fishery.

Learn More

If you’re interested in learning more about Princeton Hydro’s fisheries management or lake management services, please contact us.

Click here to download a full copy of Dr. Souza’s presentation, titled “How’s the Fishing? Maximizing the Recreational Potential of Your Lake’s Fishery,” which he recently presented at the NJCOLA Spring Meeting. The presentation provides an in-depth set of guidelines for fishery management, covering topics like data collection methods, habitat creation and enhancement, maximizing habitat quality, and details on various stocking species to consider for your lake.

NJCOLA unites lake communities throughout New Jersey through education and by formulating legislation favorable to the protection and enhancement of the State’s lake resources. NJCOLA meetings, held on a regular basis in the spring and fall, educate members on various topics and issues affecting lake communities ranging from legal to environmental.

The Spring NJCOLA meeting was well attended with over 60 participants representing lakes throughout New Jersey, including a number of lakes that are managed by Princeton Hydro - Lake Mohawk, Lake Hopatcong, White Meadow Lake, Lake Swanannona, Kehmah Lake, Culver Lake and Swartswood Lake.

To learn more about Princeton Hydro's Pond and Lake services, including water quality sampling, bathymetric surveying, floating wetland islands, and fisheries, visit: http://bit.ly/pondlake    [post_title] => How’s the Fishing? Tips for Managing Your Lake's Fishery [post_excerpt] => [post_status] => publish [comment_status] => open [ping_status] => open [post_password] => [post_name] => fishery-management [to_ping] => [pinged] => [post_modified] => 2025-11-04 02:14:54 [post_modified_gmt] => 2025-11-04 02:14:54 [post_content_filtered] => [post_parent] => 0 [guid] => http://www.princetonhydro.com/blog/?p=2151 [menu_order] => 0 [post_type] => post [post_mime_type] => [comment_count] => 2 [filter] => raw ) [9] => WP_Post Object ( [ID] => 5803 [post_author] => 3 [post_date] => 2018-06-07 20:14:14 [post_date_gmt] => 2018-06-07 20:14:14 [post_content] =>

The Lake Hopatcong Foundation (LHF) recently launched its newest initiative - a floating classroom. The custom-built 40-foot education vessel, named 'Study Hull', gives students an interactive, hands-on education experience to explore Lake Hopatcong, learn about freshwater ecology, and learn how to protect the watershed.

During its maiden voyage field trip, which was held on May 21, fourth-graders from Nixon Elementary and Kennedy Elementary schools utilized the boat’s laboratory instruments to study water hydrology, temperatures, plankton, and dissolved oxygen levels. They performed a series of tests and experiments designed to help them learn about the general health of the lake. They used Secchi Disks to determine the depth to which light is able to penetrate the water's surface. They also learned about runoff and nonpoint source pollutants, how to protect the lake’s water quality, and how to be good stewards of the water.

Princeton Hydro helped the LHF design a teaching curriculum on water quality.  Dr. Jack Szczepanski, Senior Aquatics Scientist, and Christopher L. Mikolajczyk, CLM, Senior Project Scientist, trained the staff and volunteers on the curriculum and demonstrated various water quality monitoring techniques that can be conducted with the students.

“We’re really proud to be a part of this exciting initiative,” said Mikolajczyk. “It’s really important to get kids interested in science at an early age and teach them about their surrounding environment – where their drinking water comes from, how it gets polluted, the impacts pollution has on the lake’s ecosystem, and what steps can be made to protect the lake’s water quality. We're hoping the floating classroom field trip program will make a lasting, valuable impression with these kids.”

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In the first year of operation it is expected that the Study Hull will host 1,000 fourth grade students. The long-term goal is to develop lesson plans for students in every grade from kindergarten through high school. Starting in July, the LHF is also offering the public tours of the floating classroom on Mondays at Hopatcong State Park.

The purchase of the floating classroom was made possible by financial support from USATODAY Network’s “A Community Thrives” program, which awarded the LHF with a $50,000 grant. The program recognizes three categories: arts and culture, education, and wellness. In each category, the first place winner received a $100,000 grant and the second and third place winners received $50,000 grants. The James P. Verhalen Family Foundation and the Szigethy Family also provided significant donations to help bring the floating classroom to life.

The LHF and Princeton Hydro are longtime partners. Starting back in 1983, Princeton Hydro’s Dr. Stephen Souza conducted the USEPA funded Diagnostic Feasibility study of the lake and then authored the Lake Hopatcong Restoration Plan. That document continues to be the backbone of why and how to restore the lake, manage the watershed, reduce pollutant loading, and address invasive aquatic plants and nuisance algae blooms.

Lake Hopatcong has one of the longest, continuous, long-term ecological databases in New Jersey; almost 30 years of consistently collected water quality data. The data is crucial in assessing the overall ecological health of the lake and proactively guiding its management, identifying and addressing emerging threats, documenting project success (a mandatory element of funding initiatives) and confirming compliance with New Jersey State Water Quality standards.

Princeton Hydro’s most recent work for Lake Hopatcong includes the implementation of green infrastructure stormwater management measures, installation of floating wetland islands to improve water quality, and invasive aquatic plant species management programs, community educational training, and surveys.

For more information about the Lake Hopatcong Foundation or the floating classroom, click here. For more information about Princeton Hydro’s lake management services, go here.

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The New Jersey Department of Environmental Protection (NJDEP) recently announced $8 million in Water Quality Restoration Grants to support projects that reduce nonpoint source pollution, mitigate harmful algal blooms, restore riparian areas, and enhance watershed and climate resilience. Funded through Section 319(h) of the federal Clean Water Act and administered by the DEP's Watershed and Land Management Program, these grants were awarded to municipalities, nonprofit organizations, and academic institutions across the state.

Princeton Hydro is proud to be a partner on five of the 17 funded projects. Our contributions vary by project and encompass activities such as engineering design, water quality assessment, watershed-based planning, and technical support for implementing stormwater and habitat restoration measures. Let's take a deeper look at these collaborative efforts:

1. The Watershed Institute – Watershed-Based Planning for Assunpink Creek

The Watershed Institute received $205K in 319(h) grant funding to develop a watershed-based plan for the Assunpink Creek watershed, located within the Raritan River Basin. This watershed spans 11 municipalities across two counties, where varied landscapes and demographics share common challenges such as localized flooding, stormwater management, and water quality degradation, highlighting the need for a coordinated, watershed-wide, science-driven approach.

The plan will evaluate pollution sources and identify large-scale restoration opportunities, including green infrastructure and riparian buffer restoration, to improve water quality and reduce flooding. It will also assess the cost, feasibility, and pollutant reduction potential of proposed measures to ensure practical implementation. Princeton Hydro supported the Institute in developing the grant proposal and planning framework, leveraging our expertise in watershed-based planning to prioritize nature-based solutions that address both water quality and climate resilience. This initiative represents a critical step toward regional collaboration, enabling upstream and downstream communities to work together on strategies that strengthen watershed health, protect public safety, and build long-term resilience.


2. Lake Hopatcong Commission – Watershed-Based Stormwater BMPs

The Lake Hopatcong Commission (LHC) was awarded $366K to retrofit an existing stormwater detention basin between King Road and Mount Arlington Boulevard in Roxbury Township. This retrofit is part of a larger Watershed Implementation Plan that Princeton Hydro developed in collaboration with LHC, which prioritizes nutrient reduction and stormwater management strategies across the Lake Hopatcong watershed. Over the past several years, LHC has actively implemented multiple elements of this plan to address harmful algal blooms (HABs) and improve water quality.

For this project, Princeton Hydro is providing engineering design and technical oversight to transform the existing basin into a green stormwater infrastructure system that slows, captures, and naturally treats runoff before it enters King Cove. The design incorporates native vegetation, invasive species management, and erosion control measures to stabilize soils and filter pollutants, reducing nutrient loading, which is one key driver of HABs. Public outreach and pre- and post-construction water quality monitoring will ensure performance tracking and measurable improvements. This basin retrofit represents a critical step in a coordinated, science-based approach to restoring ecological health and water quality in New Jersey’s largest lake.


3. Cozy Lake, Jefferson Township – Addressing Emerging Contaminants

Jefferson Township received $350K in grant funding to develop an Emerging Contaminants Management Plan for Cozy Lake, focusing on cyanotoxins and HABs. Cozy Lake is a 28-acre waterbody within a 1,152-acre sub-watershed that includes both forested (60%) and developed (29%) land. The lake is fed by the Rockaway River at its northern end and a smaller southeastern inlet, with outflow through a dam on the western edge.

The shoreline is primarily residential lawn with minimal emergent wetlands, and several inlets and rock-lined drainage ditches exhibit erosion and lack slope protection, contributing to sediment loading. Princeton Hydro provided early technical input to shape this innovative project with the creation of a comprehensive Jefferson Township Lake and Watershed Restoration and Protection Plan. As part of the plan, Princeton Hydro made recommendations for Cozy Lake, which included enhancing shoreline buffers with native vegetation and installing living shorelines at select properties to stabilize soils, filter stormwater and reduce nutrient loading, improve habitat quality, and enhance community access. These measures, combined with in-lake monitoring and proactive management strategies, will help mitigate HABs and protect ecological and public health.


4. Rockaway Township – Watershed-Based Green Infrastructure

Rockaway Township received $399K in grant funding to implement elements of its Watershed Implementation Plan, focusing on green infrastructure stormwater management and nutrient reduction to improve water quality. The project will retrofit the municipal complex by converting a rock-lined drainage swale into a vegetated swale with a bioretention basin, designed to filter stormwater runoff and reduce nonpoint source pollutants entering Fox’s Pond and Fox Brook.

Princeton Hydro played a key role in developing the Watershed Implementation Plan, which encompasses 11 private lakes within the Rockaway River watershed, prioritizing critical locations for intervention and designing cost-effective green infrastructure BMPs. This regional approach aligns with strategies recommended by NJDEP and the Highlands Council. The plan included a comprehensive watershed-based assessment to identify and quantify factors contributing to eutrophication, evaluate management measures, estimate costs, and establish an implementation schedule. Princeton Hydro authored the final report, which guided the Township in applying for the Section 319(h) grant and now informs the design and construction of green stormwater infrastructure that will deliver measurable water quality improvements while supporting ecological restoration goals.


5. Green Trust Alliance – Green Infrastructure and Community Engagement

Green Trust Alliance (GTA), a nationally accredited land trust and public charity dedicated to accelerating large-scale conservation, received $1.39 million in NJDEP funding to implement green infrastructure improvements at Pinelands Regional High School in Tuckerton, New Jersey. This initiative targets the Tuckerton Creek watershed, which drains into Tuckerton Creek and ultimately flows into Barnegat Bay—a critical estuary spanning 33 municipalities in Ocean County and four in Monmouth County. The retrofit will transform the school’s stormwater detention basin into a multi-functional system that mimics natural hydrology, enhances flow control, and improves water quality locally and in the larger Barnegat Bay watershed.

Working with GTA and GreenVest, Princeton Hydro is serving as the design engineer, applying nature-based engineering and ecological restoration techniques to intercept, evapotranspire, and infiltrate stormwater runoff at its source. In addition to its technical objectives, the effort includes a strong community engagement component and an educational platform for students. By bringing green infrastructure into the school environment, the initiative provides hands-on experience with water resources, stormwater management, and ecological engineering, help to build STEM skills while fostering a deeper connection to the surrounding landscape and an understanding of how natural systems work together to support environmental and community health.


Princeton Hydro also assisted several of these partners in developing successful NJDEP Section 319(h) grant applications, providing technical documentation, conceptual designs, and pollutant load reduction estimates to strengthen the proposals.

To date, the Murphy Administration has awarded more than $33M in Water Quality Restoration grants to improve the health of waterways in all corners of the state. Click here to read about all the 2025 grant funding recipients and their innovative projects.

As NJDEP Environmental Protection Commissioner Shawn M. LaTourette noted in the department's press release, “Enhancing the ecological health of our lakes, rivers, streams and coastal waters has long been a priority of the Murphy Administration. The Department of Environmental Protection is pleased to award these grants that will help our partners advance a variety of strategies to improve the health of these waterways and enhance the quality of life in our communities.”

We are proud to play a continued role in advancing that mission: helping communities implement practical, data-driven solutions that make a measurable difference for New Jersey’s waterways and the people who depend on them. Click here to learn more about our work to protect natural habitat and restore water quality throughout the New Jersey.

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