Lake Hopatcong Commission - Reports DEP Drops HAB level in Crescent Cove

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Testing completed by NJDEP on September 22nd confirmed the advisory level of the harmful algal bloom in Crescent Cove has been reduced from the DEP ADVISORY level to the WATCH level. Three samples were collected throughout the cove and results can be found on DEP’s HAB Dashboard at the link below.
At the WATCH level there are cyanobacteria concentrations of 20K - 80K cells/mL. These are suspected or confirmed HABs with potential for allergenic or irritative health effects. Public bathing beaches remain open, but caution should be used during primary contact activities such as swimming. Do not ingest the water, and do not consume fish. Dogs and other pets should not be allowed in the water because they are very sensitive to bacteria and will drink the water or lick it off their fur.
Use the link above to the DEP’s HAB Dashboard where you can see results and get updates by location on Lake Hopatcong. If you observe what you think might be a suspected Harmful Algal Bloom a report can be made to NJDEP at 1-877-WARN-DEP.

See the Lake Hopatcong Commission to Stay Connected:



What's Happening in Crescent Cove:

According to research done by EverBlue Lake Systems, Crescent Cove is a highly impaired area, within a moderately impaired lake system

Crescent Cove, if not the worst area in the lake, is among the top three, as you have very little wind action in the cove, and you have the natural currents of the lake bringing everything in such as trash, leaves, floating weeds and anything else floating on the lake. It becomes the natural dumping zone for the lake.

Drone Shots from 09/02/2020:


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All that vegetative matter material that grows or is transported into Crescent Cove dies and goes to the bottom of the cove making it a very fertile compost pile that accelerates weeds and harmful algae blooms (HABs) growth. There is literally a sludge pile on the bottom of the cove that acts as compost, which then stirs up the nutrients helping to feed the HABs.

“This area is the perfect breeding ground for invasive milfoil weeds and blue/green algae”, stated John Tucci

Final Design for the 70 acres of Crescent Cove:

Crescent Cove Map

The model and design for Crescent Cove is a fine defused bubble aeration system and would be the first step to create an environment within the cove that would allow for the digestion and reduction of the fertilizers and nutrients that are driving the algae and weed growth in that area. As part of the plan, 38 diffusers and 31,000 feet of airline were installed in Crescent Cove.

Our design concept for Crescent Cove needed to be overly aggressive with higher than the normal points for aeration. The volume of air was greatly increased to nearly 2CFM per acre. These changes made to the standard model help with the amount of circulation that is needed to be generated to start returning positive results. The aeration system will be completely turning over the water 1.5 times a day, where it only happens twice a year in most lakes.

At the mouth of Crescent Cove, EverBlue designed an aeration curtain that may not fully stop the inflow of junk from the rest of the lake, but it will utilize the wind and current that blows toward the back of the cove to move the aeration effects further back into the cove.

John Tucci Stated, “This system is highly configurable, and we can add or move the aerators based upon our test results.”

Verblue Fine Bubbles“We are confident with our 15 years of experience that Crescent Cove is very savable, and with the Borough of Hopatcong very aggressively working on the sewers and watershed issues, all of these systems will greatly help the overall solution. The Borough is doing some of the very best things that can be done to solve this problem.” Stated John Tucci

Under this aggressive aeration plan, we will improve water quality. We will also see less Blue/Green algae and at the same time reduce the sediments on the bottom of the cove, which will help with the nuisance weed growth. It may take one to two years to fully see all of the positive changes and weed reduction.

In the opinion of EverBlue, the aeration system for Crescent Cove is here to stay well beyond the pilot projects, as Crescent Cove will always need this assistance in the future. The installed system is high grade and expected to last 15+ years with the right maintenance.

Testing in Crescent Cove:

EverBlue has already collected the first set of water samples and will be returning every two weeks to sample further. The testing will include seven water quality results and lake sediment results. The Mayor of Hopatcong will be receiving monthly reports, which we understand he plans to make public.

Second Phase of Project using BioBlast: (Still awaiting DEP Approval)

Once the aeration system has been studied for at least 90 days, the second phase would utilize BioBlast (good bacteria) that works hand in hand with the aeration system. The aeration system helps spread the BioBlast across the affected area. This will help compete with the Blue/Green algae and weeds for any remaining nutrients, thus starving the invasive vegetation. 

If we can increase the overall fitness of the lake and it becomes healthier, the lake will have a better immune system and may well be able to fight off many of these challenges in the future on its own.


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