Harmful Algal Blooms

Public-Private Approach to Lake and Watershed Management by Chris Mikolajczyk, CLM, Princeton Hydro, July 2021

Click here to view the slides from a presentation from Chris Mikolajczyk of Princeton Hydro.  The presentation covers the basics of HABs and how government bodies and private lake associations are working together ot study the causes of HABs.  


State Fiscal Year 2019 Grants to Prevent, Mitigate and/or Control Harmful Algal Blooms (HABs) Project Descriptions by Emily McGuckin, AmeriCorps Watershed Ambassador  5/16/20


In 2019, many New Jersey lakes including a few reservoirs experienced significant algal blooms that impacted economic, recreational, and community environments. To address the crisis, the State of New Jersey approved grants totaling $2.5 million plus a matching portion of 33% to undertake experimental programs to be centered on the development of up to 15 emerging and innovative lake water treatment approaches. Results are to be shared with the public including lake associations over a time period of 12 to 36 months.  A listing of the approved grants and planned onsite projects follows:


1.  Lake Hopatcong   Grantee: Lake Hopatcong Commission  Funding Amount $500,000

Lake Hopatcong will be trying different HAB management techniques including reduction of nutrient additions, habitat modifications, and direct HAB treatments. Through these projects, evaluations and monitoring will take place to determine effectiveness of these measures.

2.  Lake Mohawk      Grantee: Lake Mohawk Preservation Foundation   Funding amount: $160,920

Lake Mohawk typically experiences cyanobacterial HABs. They will be implementing new measures to decrease HABs and within two years decrease the usage of copper-based algaecides. Measures taken include the use of Green Clean (a non-copper algaecide) and application of PhosLock (a phosphorus inactivator) and will be evaluated through water quality monitoring.

3.  Rosedale Lake   Grantee: Mercer County Park Commission   Funding Amount: $185,000

Because of the large drainage area of unfiltered runoff, this location has had extremely high HAB counts previously. Mitigation measures will be implemented to decrease the nutrient concentration for this lake and will include structural practices by installing constructed floating wetlands, barley bales* and an aerator device*. The goal is to prevent extra nutrients from entering the lake and to reduce nutrient loading within the lake.

4.  Belcher Creek and Greenwood Lake   Grantee: Greenwood Lake Commission  Funding Amount: $52,800

Belcher Creek is the main tributary of Greenwood Lake, which is located in Passaic County, NJ and Orange County, NY. This lake has extreme economic importance to both states and supplies more than 3 million people with drinking water. Mitigation measures will decrease contributing HAB factors and data will be collected to determine the ideal location for a ferric sulfate injection system* on Belcher Creek as well as Floating Wetland Island* installation.

5.  Pequannock Water Treatment Plant (WTP)  Grantee: City of Newark Department of Water and Sewer Utilities  Funding Amount: $475,000

This project will focus on HABs within Echo Lake, part of the Pequannock Watershed. Mitigation measures include the use of “sound barriers” on the water’s surface created by ultrasonic technology to block cyanobacteria from photosynthesizing. Monitoring of the lake and assessments of possible impacts will be employed.

6.  Spruce Run Reservoir  Grantee: New Jersey Water Supply Authority   Funding Amount: $115,600

This location has had extensive cyanobacterial blooms within recent years, most likely due to internal and external nutrient loads. The Mulhockaway Creek, a primary source of the reservoir, will have a biochar filter system installed on it. The goal is to remove nutrients and metals in the water at a low cost, scalable installation.

7.  Budd Lake   Grantee: Township of Mount Olive  Funding Amount: $365,000

Budd Lake is the headwaters of the South Branch of the Raritan River and is a naturally spring fed glacial lake. Mitigation measures will include a 3-year program to reduce nutrient loading within the lake via continuing and increasing aquatic weed harvesting and application of herbicide and treatment of aluminum sulfate. Other measures include chemical treatment of HABs. Water quality monitoring will be performed and will be treated with additional chemical measures if needed

8.  Branch Brook Lake and Deal Lake   Grantee: New Jersey Institute of Technology   Funding Amount: $500,000

Implementation of a 3-year project using a floating platform to remove HABs using air micro-nano bubble generators. The aim is to clarify affected water columns as deep as 4-6 ft. Additionally, improvements in dissolved oxygen and turbidity is the goal for Branch Brook Park Lake.

9.  Lake Hopatcong Crescent Cove  Grantee: Borough of Hopatcong  Funding Amount: $145,680

This project will utilize a lake-bottom Diffused Aeration System beginning at the River Styx Bridge and will cover the Crescent Cove area.


*Aerator device: device to pump air through the water column to disrupt bacteria behavior.

*Barley bales: mesh enclosed bales of barley that release oxygenators to clear water 

*Ferric sulfate injection systems: injection of ferric sulfate into water bodies to pull solids out of the water column to possibly reduce pH levels

*Floating Wetland Islands: man made islands that help increase habitat for aquatic organisms and can decrease the pollution amounts through plant filtration



LMCC Awarded the NJDEP Grant to Prevent, Mitigate and /or Control Harmful Algal Blooms!!! 


In response to the 2019 Harmful Algal Blooms (HAB) experienced by numerous lakes in New Jersey, the Governor initiated a total $2.5million in grant funding to improve water quality this year.  

A project was developed for Lake Mohawk with the assistance of Princeton-Hydro and Dr. Stephen Souza that addresses all three goals of the grant - Prevent, Mitigate and Control Harmful Algal Blooms in the most prevalent algal growth areas of Lake Mohawk and Upper Lake Mohawk.  This project was approved and awarded the total funding amount requested!


The Project:

PhosLock © Treatment – Similar to the current Alum treatments, PhosLock strips the water column of phosphorus, algal food, and inactivates whatever phosphorus it binds to in the lake bottom sediments.  

The benefits to this treatment over Alum is the overall effectiveness as well as temperature stability.  Phosphorus bound by Alum is released as the water temperature rises.  This is normally experienced in August when the water temps. are the warmest and the algae at its worst.  This treatment will be applied in Turtle Cove in early May. 

GreenClean © Treatment – These treatments are an alternative to the copper-based algaecides currently used in the Lakes.  The benefits to this treatment over copper is the effectiveness as well as the breakdown of the cyanotoxins (byproduct of HABs).  Other algaecides including copper kill the algae and result in algae lysing – cell rupture.  This releases all of the phosphorus within the algae back into the water creating the vicious cycle of treating one bloom only feed the next one.  Numerous treatments will be applied in Tamarac Cove, Happy Valley Beach, and the eastern cove of Upper Lake. 

Monitoring – To judge which of these treatments works best combat HABs in our lakes, extensive water quality monitoring will be conducted.  This will include pre- and post-treatment monitoring at each of the subject areas throughout the 2020 season.  The resulting data from these individual sites as well as the overall Lake quality will be evaluated against historic data for baseline comparative analysis.   

End Game – Much time, effort, and money has been dedicated on lake water quality management specific to medium and deep water bodies, usually reservoirs.  And while it is paramount to ensure drinking water sources remain safe, it is important to the Lake Mohawk community that the methods and treatments developed for deep water bodies be tested and evaluated for effective application to shallow lakes.  So this project will not only benefit the 2020 season but the development of an annual HAB prevention and mitigation plan. Being proactive is always better than reactive!!!   

In light of the COVID-19 quarantine conditions, special exceptions were obtained to continue this work as scheduled.  Our first round of sampling results have returned with good results indicating ideal early season conditions with a healthy balance of phytoplankton, low phosphorus concentrations, and no measurable cyanobacteria presence. 

Note:  Grant studies conducted by LMCC to be shared with NJCOLA at appropriate times during 2020 – 2021

Sabine Watson PE

Staff Engineer

Lake Mohawk Country Club



NJCOLA has just added this new area to the website to include articles, meeting announcements and upcoming public forms and presentations on HAB (Harmful Algal Blooms), a concern of many who live in lake communities.  

Two presentations from the August 20, 2019 HAB public forum are available by accessing these links: "Funding Opportunities: Can a Stormwater Utility Be a Solution?" and "Managing Stormwater Runoff to Our Lake."

Stephen Souza, Clean Waters Consulting LLC. was a recent presenter at a COLA quarterly meeting on 9/14//19. Please refer to part 2 of his presentation  (page 60): "What the HABs is going on?


HAB LAKE CLOSURES  – The stakes have been raised  by Alan Fedeli, NJCOLA,  April, 2019      

For years we’ve been swimming in lakes that occasionally develop blue-green algae (cyanobacteria) blooms.  Our treatment companies have knocked down the blooms with Copper Sulfate, and the problem seemed contained.  The game has changed.  In recent years, NY State’s DEC and NJ’s DEP have been testing lakes for Harmful Algal Blooms (HABs) and asking the state Departments of Health to close the lakes if the “microcystins concentrations” exceeds a certain threshold.  It can take up to three weeks to re-open a lake depending on weather and site specific conditions.  This can be a disaster for a lake closed mid-summer.

How bad is the problem?

We’ve been swimming in lake water during algae blooms for years.  We’ve been exposed to cyanobacteria, but haven’t ingested the water, deliberately.  We might have attributed swimmer’s rashes to these conditions.  But now scientists are studying whether there is a correlation between long term cyanobacteria exposure and serious nerve diseases such as ALS.  As you would expect, lakes that have elevated microcystins concentrations are closed due to an abundance of caution.  Not to trivialize the issue, most parents of small children would keep their kids out of a lake even if there was the slightest risk of serious illness over time.

What can we do about this problem?

It behooves lake communities to take algal blooms more seriously, particularly if they are composed of cyanobacteria (also known as blue-green algae), which are the cause of more HABs in freshwater systems.  While copper sulfate can kill the algae and temporarily improve conditions, the copper lyses the cells (they burst) and cyanotoxins such as microcystins can be released into the water making them more readily available for uptake.  Thus, copper sulfate must be carefully and strategically used as part of a larger lake / HABs Management Plan.  Simply relying completely on copper sulfate does not address the cause of the problem (elevated nutrient concentrations) and can make the situation worse, such as producing larger, secondary blooms, impact non-target organisms, and actually making it easier for cyanotoxins to impact other organisms, including livestock, pets and humans.  Thus, we must redouble our efforts to avoid algal blooms “at all costs” if we expect to keep our lakes viable for swimming and other recreational purposes.

How do we avoid HABs?

We need to employ more science and testing than we’ve ever done to learn the extent to which our problem is external or internal nutrient loading, and take steps to correct the sources of the problem.  We must also do more testing to anticipate the onset of a bloom and take proactive measures.  We have to ensure that we’ve engaged the best scientific help in keeping our lakes as healthy as possible.                                                                                                     


Harmful Algal Blooms (HAB) - 2017

During the summer of 2017 Swartswood Lake experienced three Harmful Algal Blooms (HAB). Apparently Swartswood Lake experienced the first recorded HAB event in New Jersey, although subsequently HAB’s occurred in at least eight other New Jersey lakes during 2017. HAB’s have only recently been recognized by the industry as potentially harmful toxic events.

At the April 21, 2018 COLA meeting, guest speaker, Victor Poretti, Section Chief, NJDEP Buereau of Freshwater and Biological Monitoring, delivered an informative presentation on "Cyanobacterial Harmful Algal Blooms (HABs) - Freshwater Recreational Response Strategy and Guidance." This presentation covered several topics including the cause of algal blooms, exposure risks, monitoring and response, key contact information, treatment advisories, key contacts and websites for additional information.

Also, check out the DEP podcast on this subject: https://njdep.podbean.com/e/episode-71-cyanobacterial-harmful-algal-blooms-with-victor-poretti-and-rob-newby/


Past COLA Presentations

"2017 HAB Experience at Swartswood Lake"  presented by Randall Sprague at NJ COLA meeting (September 16, 2017).


The focus of this presentation was to inform the NJCOLA community on the Swartswood Lake experience, provide examples of what HAB’s might look like, identify the potential risk to humans and identify steps lake communities can prepare so that they can more rapidly respond to an HAB should it occur.The information contained in the presentation is based upon publications and web information by the World Health Organization, United States Environmental Protection Agency, New York State Department of Environmental Conservation and New Jersey Department of Environmental Protection (NJDEP). Website relied upon for the presentation are identified in the slides. Also NJDEP and Swartswood Lakes and Watershed Association met on Thursday September 14, 2017, which is factored into the presentation. It should be noted additional HAB information is contained in presentation materials by Fred Lubnow of Princeton Hydro.