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Excess phosphorus and nitrogen can rapidly degrade ecological conditions, limit recreational use, impact sources of potable water, and increase management costs, often despite the implementation of conventional best management practices. As a result, there is growing interest in tools that can complement or augment existing approaches and address nutrients in more targeted ways. Biochar has emerged as one such tool. While it is best known as a soil amendment, its physical, chemical, and biological properties have prompted increasing use in aquatic systems as a means of improving water quality. Over the past five years, Princeton Hydro has applied biochar in a range of lakes, ponds, streams, and stormwater-related settings across Pennsylvania, New Jersey, and New York. These field applications, supported by monitoring, have provided important insight into when biochar is most effective, where its limitations lie, and why observed improvements in water quality are not always explained by phosphorus removal alone. [gallery link="none" size="medium" ids="9215,19122,9225"] What Is Biochar and Why Use It in Waterbodies? Biochar is a carbon-rich, charcoal-like material produced through pyrolysis, a process in which organic biomass is heated in a low-oxygen environment. The resulting material has a highly porous structure and extensive surface area, properties that make it effective at adsorbing nutrients such as phosphorus and nitrogen (Joseph et al., 2021). Because excess nutrients are a primary driver of eutrophication and HABs, biochar has emerged as a promising amendment for aquatic systems and stormwater best management practices (BMPs). In aquatic applications, biochar is typically installed in permeable sleeves (aka socks) or incorporated into stormwater treatment practices to intercept nutrient-rich water before it enters lakes or ponds. Used biochar can also be repurposed as a soil amendment, adding to its appeal as a sustainable, circular material. [gallery link="none" columns="2" size="medium" ids="19134,9226"] Aquatic Ecologist Katie Walston-Frederick (right) leads a biochar sleeve filling session. Katie and her team members wear full protective equipment when handling biochar due to the fine, carbon-based nature of the material. Lessons Learned from Five Years of Field Applications Through approximately half a dozen monitored projects implemented since 2020, several consistent patterns have emerged. Standing Waters Show the Strongest Response: Biochar has proven most effective in low-flow or standing water environments such as ponds and stormwater basins. In these systems, Princeton Hydro has documented total phosphorus (TP) removal rates as high as 80%, with soluble reactive phosphorus (SRP) reductions approaching 97% in some stormwater ponds (Princeton Hydro, Lake Hopatcong Report, 2022). The extended contact time between water and biochar in these settings appears to be a key driver of performance. Flow and Contact Time Matter: In streams and fast-moving stormwater infrastructure, nutrient removal rates tend to be lower, with phosphorus reductions typically closer to 50%. While still meaningful, these reduced efficiencies are largely attributable to limited contact time. Simply put, the shorter the interaction between water and biochar, the fewer opportunities there are for adsorption and other removal processes to occur. Enhancement to Conventional Stormwater BMPs: Biochar can be particularly effective when paired with stormwater BMPs that primarily rely on sedimentation. Traditional practices often excel at removing particulate-bound phosphorus but are less effective at capturing dissolved forms of phosphorus—the fraction most readily utilized by algae. Incorporating biochar into these systems can enhance removal of dissolved phosphorus, improving overall treatment performance. Streams Present Physical Challenges: Installing biochar in stream environments presents practical challenges. Even with careful anchoring, large storm events, including remnants of hurricanes, can dislodge biochar sleeves, transporting them downstream or onto streambanks. These risks must be considered during design and often limit the suitability of biochar for higher energy systems. Chemistry Alone Does Not Tell the Whole Story: At very high pH levels, phosphorus adsorption onto biochar can become less predictable, sometimes exhibiting a “decoupling” between measured phosphorus sorption and observed water quality improvements. Monitoring data from multiple projects indicate that reductions in chlorophyll-a, cyanobacteria abundance, and overall bloom severity cannot always be explained by phosphorus removal alone. Beyond Adsorption: The Role of Biology The disconnect between measured nutrient sorption and improved water quality suggests that additional mechanisms are at work. Increasingly, evidence points toward biological processes occurring within and around biochar installations. Biochar is known to favor the growth and proliferation of heterotrophic bacteria (Moore et al., 2023). These microbial communities may contribute to water quality improvements in the following ways:
Nutrient-driven water quality impairments, particularly harmful algal blooms (HABs), continue to challenge lake managers, municipalities, and watershed organizations across the Northeast. Excess phosphorus and nitrogen can rapidly degrade ecological conditions, limit recreational use, impact sources of potable water, and increase management costs, often despite the implementation of conventional best management practices. As a result, there is growing interest in tools that can complement or augment existing approaches and address nutrients in more targeted ways.
Biochar has emerged as one such tool. While it is best known as a soil amendment, its physical, chemical, and biological properties have prompted increasing use in aquatic systems as a means of improving water quality. Over the past five years, Princeton Hydro has applied biochar in a range of lakes, ponds, streams, and stormwater-related settings across Pennsylvania, New Jersey, and New York. These field applications, supported by monitoring, have provided important insight into when biochar is most effective, where its limitations lie, and why observed improvements in water quality are not always explained by phosphorus removal alone.
Biochar is a carbon-rich, charcoal-like material produced through pyrolysis, a process in which organic biomass is heated in a low-oxygen environment. The resulting material has a highly porous structure and extensive surface area, properties that make it effective at adsorbing nutrients such as phosphorus and nitrogen (Joseph et al., 2021). Because excess nutrients are a primary driver of eutrophication and HABs, biochar has emerged as a promising amendment for aquatic systems and stormwater best management practices (BMPs).
In aquatic applications, biochar is typically installed in permeable sleeves (aka socks) or incorporated into stormwater treatment practices to intercept nutrient-rich water before it enters lakes or ponds. Used biochar can also be repurposed as a soil amendment, adding to its appeal as a sustainable, circular material.
Through approximately half a dozen monitored projects implemented since 2020, several consistent patterns have emerged.
Standing Waters Show the Strongest Response: Biochar has proven most effective in low-flow or standing water environments such as ponds and stormwater basins. In these systems, Princeton Hydro has documented total phosphorus (TP) removal rates as high as 80%, with soluble reactive phosphorus (SRP) reductions approaching 97% in some stormwater ponds (Princeton Hydro, Lake Hopatcong Report, 2022). The extended contact time between water and biochar in these settings appears to be a key driver of performance.
Flow and Contact Time Matter: In streams and fast-moving stormwater infrastructure, nutrient removal rates tend to be lower, with phosphorus reductions typically closer to 50%. While still meaningful, these reduced efficiencies are largely attributable to limited contact time. Simply put, the shorter the interaction between water and biochar, the fewer opportunities there are for adsorption and other removal processes to occur.
Enhancement to Conventional Stormwater BMPs: Biochar can be particularly effective when paired with stormwater BMPs that primarily rely on sedimentation. Traditional practices often excel at removing particulate-bound phosphorus but are less effective at capturing dissolved forms of phosphorus—the fraction most readily utilized by algae. Incorporating biochar into these systems can enhance removal of dissolved phosphorus, improving overall treatment performance.
Streams Present Physical Challenges: Installing biochar in stream environments presents practical challenges. Even with careful anchoring, large storm events, including remnants of hurricanes, can dislodge biochar sleeves, transporting them downstream or onto streambanks. These risks must be considered during design and often limit the suitability of biochar for higher energy systems.
Chemistry Alone Does Not Tell the Whole Story: At very high pH levels, phosphorus adsorption onto biochar can become less predictable, sometimes exhibiting a “decoupling” between measured phosphorus sorption and observed water quality improvements. Monitoring data from multiple projects indicate that reductions in chlorophyll-a, cyanobacteria abundance, and overall bloom severity cannot always be explained by phosphorus removal alone.
The disconnect between measured nutrient sorption and improved water quality suggests that additional mechanisms are at work. Increasingly, evidence points toward biological processes occurring within and around biochar installations.
Biochar is known to favor the growth and proliferation of heterotrophic bacteria (Moore et al., 2023). These microbial communities may contribute to water quality improvements in the following ways:
This emerging science mirrors what Princeton Hydro has observed in the field: water quality can improve in ways that chemical measurements alone do not fully explain, suggesting that biological processes may be playing an important supporting role.
Since 2020, Princeton Hydro has applied biochar across a range of aquatic and stormwater settings, tailoring each installation to site-specific conditions and management goals. Together, these projects demonstrate biochar’s versatility and its ability to integrate into holistic watershed and lake management strategies, often working best when paired with other nature-based and engineered solutions.
At Duke Farms, a 2,700-acre estate in New Jersey, Princeton Hydro has supported lake and wetland management efforts for more than two decades. Biochar was recently introduced as an additional tool within an established, science-based nutrient management program. By placing biochar in low-flow areas where contact time could be maximized, phosphorus removal was enhanced and improvements in water clarity were observed. This effort highlights how biochar can be layered into long-term management strategies alongside floating wetland islands and other nature-based solutions.
Harvey’s Lake, the largest natural lake in Pennsylvania, has long faced challenges associated with nutrient loading and recurring HABs. As part of a broader stormwater management effort, Princeton Hydro incorporated biochar into select stormwater BMPs to reduce phosphorus before it entered the lake. Installed within targeted stormwater conveyance and treatment features, the biochar helped achieve measurable reductions in dissolved phosphorus, complementing other watershed-scale measures such as vegetated buffers and wetland enhancements. The spent biochar, having captured phosphorus and nitrogen from runoff, was then repurposed as a soil amendment to enrich a 500-square-foot pollinator garden. This repurposing effort served a dual purpose: demonstrating a closed-loop approach to managing excess nutrients while also creating a community-oriented space that supports local biodiversity.
Across multiple stormwater projects in New Jersey and Pennsylvania, biochar has been installed in detention basins, rain gardens, and other stormwater treatment devices. These applications were designed to target dissolved phosphorus, a nutrient form that conventional BMPs can struggle to remove. In several cases, biochar was paired with other nutrient control measures such as floating wetland islands to further improve nutrient capture. Collectively, these projects illustrate how biochar can be adapted and scaled to address local water quality challenges across diverse settings.
At Lake Hopatcong, New Jersey’s largest lake, biochar was deployed as part of a comprehensive, multi-pronged strategy to reduce nutrient concentrations and mitigate HABs. Biochar was installed in permeable flotation bags and placed at targeted shoreline and inlet locations where nutrient loading is most pronounced, including several stormwater inlets and outlets around the lake. Funded through the NJDEP Freshwater HABs Prevention & Management Grant Program and implemented in partnership with the Lake Hopatcong Commission and the Lake Hopatcong Foundation, these installations complemented other in-lake management measures such as floating wetland islands.
In Manhattan's Central Park, Princeton Hydro supported the Central Park Conservancy in developing and implementing a long-term management strategy for the park's network of lakes and ponds, where harmful algal blooms driven by excess nutrients were a persistent concern. As part of a broader, phased approach to improve water quality, biochar was incorporated as a nutrient reduction tool and will be incorporated alongside other measures such as floating wetland islands, aeration and circulation, and stormwater treatment techniques. Used in targeted locations, biochar helped support efforts to reduce nutrient loading and mitigate cyanobacteria blooms within these highly visible urban waterbodies.
Across these projects, biochar installations have been associated with measurable reductions in total and dissolved phosphorus, decreases in chlorophyll‑a concentrations, and lower cyanobacteria cell counts. While performance has varied by site, the strongest and most consistent results have occurred in enclosed or low‑flow environments where contact time is maximized and physical disturbance is minimized. When thoughtfully designed and integrated with other BMPs, these case studies show how biochar can contribute meaningfully to broader efforts to reduce nutrient loads and improve overall water quality.
Biochar is not a one-size-fits-all solution. Reviewing site-specific water quality data is essential to determine whether biochar is an appropriate standalone treatment or should be combined with complementary approaches. Ongoing and future research is focused on better quantifying the relative contributions of chemical adsorption and biological activity associated with biochar. Current studies, including collaborative efforts with academic partners, aim to document pollutant removal capacity, characterize microbial communities, and evaluate biochar’s potential role in degrading cyanobacteria and cyanotoxins. As these processes continue to be studied and further understood in the water quality context, biochar may become an increasingly valuable component of integrated, science-based watershed management strategies.
On July 31, 2023, renowned limnologist Dr. Robert Evan Carlson passed away after his battle with Parkinson’s disease and multiple myeloma. Below is a statement by Princeton Hydro’s Senior Technical Director of Ecological Services, Dr. Fred S. Lubnow, who speaks for all of us at Princeton Hydro, on the legacy that Dr. Carlson left on the field of limnology.
“The field of limnology, and ecology in general, recently lost one of its greats with the passing of Dr. Robert Evan Carlson. His contributions to the fields of limnology and lake management were numerous, but he is best known for the development of the Carlson Trophic State Index (TSI). This is an internationally accepted protocol of assessing the health of lakes, ponds, and reservoirs that is used by everyone - from lake associations and ecological consultants to local, state, and federal governments - as a means of determining both declines in water quality due to increased nutrient loading and/or climate change, and improvements through watershed management and in-lake control measures.
As mentioned in his obituary, Dr. Carlson created the Secchi Dip-in, which is an annual summer event where volunteers measure the clarity of lakes throughout North America to develop a database on the overall health and status of our inland waterbodies. This program has grown to be a staple during Lakes Appreciation Month in July, and his tradition will continue on in every sample collected by volunteers.
As both a professor at Kent State University and an environmental consultant through his company Clearwater Environmental Consulting, Inc., Bob was an incredible source of information on measures to restore, protect, and preserve our aquatic ecosystems. On a personal note, I have met and spoken with Bob from time to time at the North American Lake Management Society’s annual conferences, and he was always willing to discuss and share his knowledge on lakes. Bob was always very friendly and generated a passion for freshwater ecology and management that was contagious. Bob will be sorely missed, but his legacy will live on as the TSI is widely used and the Great Secchi Dip-In continues in the future! Rest in Peace.”
A celebration of his life will be held on Saturday, November 4, 2023 at 2:00 PM at the Kent United Church of Christ, 1400 E. Main St. Kent, OH 44240. Donations in Bob’s memory can be made to the Dr. Robert E. Carlson Scholarship in Ecology and Evolutionary Biology at Kent State University. This scholarship offers stipends for students to travel to professional conferences, reflecting his passion for helping students in their studies and professional careers. Gifts to this scholarship fund can be made payable to The Kent State University Foundation and sent to The Kent State University Foundation, Attn: Gift Processing; P.O. Box 5190, 350 S. Lincoln St., Kent, Ohio 44242.
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.
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.
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.
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.
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.
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.
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.
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).
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.
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.
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.
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?
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.
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.
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.
Harmful Algal Blooms (HABs) are rapid, large overgrowths of cyanobacteria. Cyanobacteria, also known as blue-green algae, aren’t actually algae, they are prokaryotes, single-celled aquatic organisms that are closely related to bacteria and can photosynthesize like algae. These microorganisms are a natural part of aquatic ecosystems, but, under the right conditions (primarily heavy rains, followed by hot, sunny days), these organisms can rapidly increase to form cyanobacteria blooms, also known as HABs.
HABs can have severe impacts on waterbodies causing significant water quality issues and often forming a visible and sometimes odorous scum on the surface of the water. HABs negatively impact economic health, especially for communities dependent on the income of jobs and tourism generated through their local lakes and waterways. And, HABs can produce toxins that are incredibly harmful (even deadly) to humans, aquatic organisms and animals, including beloved pets, wildlife, and livestock.
The health impacts and symptoms can vary depending on the size and type of animal, how an animal is exposed to the cyanobacteria, how long they were exposed, which type of toxin was present, and how much toxin was present.
Swimming in waters with even low concentrations of cyanotoxin may cause skin rashes, ear/throat infections, and gastrointestinal distress. When ingested, the impacts can be even more severe. The toxins can cause liver, kidney, and nerve damage, and, at high concentrations, cyanotoxins can be lethal.
Animals are often the first effected, in part because they are more likely to swim in or drink from bodies of water that contain cyanobacteria. Dogs are among the most vulnerable victims because they will swallow contaminated water when playing in waterbodies where the existence of toxins may not be noticed. Livestock and wild animals are also susceptible to injecting toxins when drinking from contaminated water sources.
Earlier this year, researchers released a study concluding that a neurotoxin generated by cyanobacteria is responsible for the deaths of eagles and waterbirds. After about 30 years of research, scientists were able to determine that cyanotoxins are the cause of a wildlife disease called vacuolar myelinopathy, a fatal neurological disease that affects various waterbirds, raptors, and, most commonly, bald eagles.
Signs of cyanobacterial poisoning can occur within 30 minutes to a few hours after exposure. In severe cases, animals, specifically dogs, can show signs of cyanobacterial poisoning within a few minutes. Common symptoms can include:
Seek veterinary care immediately and/or call the Poison Control Center if you think your pet or livestock may have symptoms caused by harmful algae, cyanobacteria, or their toxins.
24-Hour Pet Poison HotlinesAnimal Poison Control Center: (800)-213-6680ASPCA: (888) 426-4435.
The New York State Department of Environmental Conservation recently released the following safety guidance related to animals and HABs:
“Keep animals, your pets, or livestock out of any surface scums or heavily discolored water, or rinse them with clean water if they are exposed to blooms. HABs can stick to and become concentrated on animal fur, creating a health risk when the animal grooms itself. This is particularly important because HABs may release a fast-acting nerve toxin that can be dangerous for pets, especially dogs that swim in blooms…” 2021. NYSDEC. Harmful Algal Blooms (HABs) Additional Information.
“Keep animals, your pets, or livestock out of any surface scums or heavily discolored water, or rinse them with clean water if they are exposed to blooms. HABs can stick to and become concentrated on animal fur, creating a health risk when the animal grooms itself. This is particularly important because HABs may release a fast-acting nerve toxin that can be dangerous for pets, especially dogs that swim in blooms…”
There are more steps you can take to protect yourself and your pets from getting sick from harmful algae and cyanobacteria:
A great tool for tracking and reporting HABs is the bloomWatch App. You can use bloomWatch to locate HABs and you can report potential HAB sightings to your local officials. Get more info here. Additionally, the NYDEC’s New York HAB System displays the location of current freshwater (non-marine) HABs throughout New York State; check it out here.
For additional HABs-related health and safety guidance, visit NYSDEC's Information about Harmful Algal Blooms webpage.
To learn about some of the things Princeton Hydro is doing to prevent, mitigate, and treat HABs, visit our recent blog:
Biochar is a pure carbon, charcoal-like substance made from organic material. Archeological studies indicate populations of native Amazonians began using biochar over 2,000 years ago to amend nutrient-poor soils to increase agricultural productivity and enhance soil fertility.
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.
Biochar improves water quality by removing nutrients from waterbodies. Biochar can be placed in floatation balls, cages, or bags/socks, which are then tethered along the shoreline and in critical locations throughout the waterbody, like where an inlet enters a lake.
Princeton Hydro recently installed biochar floatation bags in four waterbodies throughout Hemlock Farms. Environmental Scientists, Johnny Quispe and Will Kelleher, captured footage from the field and provide a brief overview of the installation process:
As shown in the video, biochar bags (aka socks) were attached to an anchor and a buoy using various lengths of rope. The various lengths of rope ensure that the biochar bags are distributed throughout the entire water column. For example, in cases where the buoy location is somewhat shallow, some of the biochar bags that have short ropes will stay near the surface of the water and those with longer ropes will rest toward or completely on the bottom of the waterbody.
Our team installed biochar bags in four locations in Hemlock Farms: Willow Pond, Wish for Fish Pond, Falling Brook Pond, and the south end of McConnell Lake. The biochar bags were placed in front of each waterbody's outfall in order to remove excess nutrients.
Thanks to Johnny and Will for capturing great footage and providing helpful insights into biochar implementation for water quality management! To learn more about biochar, check out our blog about a biochar installation at Lake Hopatcong in New Jersey.
It’s officially time to say goodbye to winter and “spring” your pond out of hibernation mode. We’ve put together six tips for getting your pond ready for Spring and ensuring it remains healthy all year long.
The first step in preparing your pond for Spring is to give it a thorough cleaning. Remove leaves, debris, and any surface algae that may have accumulated over the winter. For shallow ponds, you may be able to use a net or pond rake to remove debris and sediment from the bottom and along the perimeter of the pond.
Inspect your pond, including berms, outlet structures, and trash racks for any damage that may have occurred over winter due to ice. If you observe any damage, we recommend contacting a professional right away. One of our engineers or certified pond managers can determine if the damage is superficial or requires more significant repairs. Also, if your pond is equipped with an aeration system, before starting it up, be sure to schedule a system inspection. A thorough inspection and proper start-up procedure will ensure the system remains fully and effectively operational for the entire summer.
The routine testing of your pond’s water quality is an important part of preventing harmful algae growth, fish kills, and other problems. We recommend conducting a “Spring start up” water quality analysis of your pond. The resulting data will inform the management process and allow for the development of a pro-active, eco-friendly management plan. Maintaining your pond's water quality helps to control nuisance aquatic species and promote environmental conditions supportive of a healthy and productive fishery.
It’s important to check the pond’s shoreline for any signs of erosion. Mowing to the water line, especially in ponds that have fluctuating water levels, can lead to severe shoreline erosion. Eroding shorelines can be easily stabilized by planting native, riparian plants.
Deep-rooted, native emergent aquatic vegetation is able to tolerate alternating periods of exposure and dry inundation. The correct combination of native aquatic plants, emergent wetland plants, and transitional upland plants can correct or prevent chronic shoreline erosion problems. A properly planted (aquascaped) edge beautifies the shoreline, stabilizes erosion problems, creates fish and amphibian habitat, attracts pollinating species and a variety of birds, and decreases mosquito breeding.
Sub-surface aeration systems eliminate stagnant water and keep your pond thoroughly mixed and properly circulated. These systems are the most cost-effective and energy-efficient way to maintain proper pond circulation. Proper aeration enhances fish habitat, minimizes the occurrence of algae blooms, and prevents mosquito breeding. It's best to contact a certified lake/pond manager to first determine if aeration is the right solution for you. If it is, an aeration system tailored to your pond's needs can be designed and installed.
There is more to pond management than weed and algae treatments alone. There is also a big difference between simple pond maintenance and ecologically-based pond management. A customized pond management plan acts as a “blueprint” that guides proactive, long-term care for your pond.
Our certified lake and pond managers can assess the status of your pond and provide you with an environmentally holistic management plan that is based on the unique physical, hydrologic, chemical, and biological attributes of your pond. A management plan identifies the causes of your pond’s problems and provides you with the guidance needed to correct these problems. The results are far more environmentally sustainable than simple (and often unnecessary) reactive weed and algae treatments.
To learn more about our lake and pond management services or schedule a consultation, visit our website.
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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.
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.
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.
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.
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 phosphorus and nitrogen stormwater pollution often emanating from highly developed communities and/or agricultural 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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