December 16, 2020| Environment
By: Lake Hopatcong Foundation/Lake Hopatcong Commission
Throughout 2020, several projects were implemented on Lake Hopatcong with the goal of evaluating innovative technologies to control, prevent, or mitigate HABs on the lake. These projects were funded through the NJDEP HAB Grant awarded to the Lake Hopatcong Commission in partnership with the Lake Hopatcong Foundation and other project partners.
Below is a summary of those efforts from the Lake Hopatcong Commission.
Since the HAB grant was awarded in early March the Lake Hopatcong Commission and Lake Hopatcong Foundation have been working with our grant partners to implement projects to reduce the impacts of HABs in Lake Hopatcong. Aeration systems, phosphorus-locking technologies, stormwater infrastructure upgrades, and newly planted rain gardens were completed over the past nine months. The purpose of each project was to trial innovative technologies and evaluate their ability to control, mitigate, or prevent HABs. Through this process, we can develop a lake management strategy that incorporates only the most effective technologies.
Priority was given to projects that could mitigate or prevent HABs early in the season such as Phoslock and Biochar applications. Early results of Phoslock monitoring indicate reductions in phosphorus, cyanobacteria, and an increase in water clarity in Landing Channel and Ashley Cove where treatments were completed. Another early-season project, Biochar, was installed in four streams, two stormwater ponds, and two stormwater manufactured treatment devices. Preliminary results show that the product is effective in removing phosphorus in all scenarios, however, it is most effective when fully submerged in water. Future installations may occur directly in the lake rather than in streams to take full advantage of its phosphorus locking capabilities.
A rain garden workshop and design program provided by Rutgers University was hosted in June with another program slated for late-winter early-spring 2021. A treatment of Green Clean a strong oxidizer and alternative treatment to copper-based algaecides was applied at CAPP Beach in Jefferson Township. Results show an increase in water clarity, but it did not reduce chlorophyll or cyanobacteria levels. Additional analysis is needed to understand the benefits of the product. Two near-shore aeration systems were installed at Lake Forest Yacht Club and Shore Hills Beach Club late this season. Evaluation of the systems in controlling and minimizing HABs will begin in Spring 2021. In addition, an aeration system installed in the Crescent Cove area by the Borough of Hopatcong showed great promise as the water in this area showed incredible improvement by August and we eagerly await to see how it does in a full 2021 season.
While we have accomplished a lot this season we still have a few more projects to finish including the cleanout and replacement of filter material in two manufactured treatment devices in Crescent Cove. Installation of Biochar in additional locations throughout the watershed will be completed in the spring as well as continued monitoring and evaluation of the technologies already installed this year.
For more details on the projects and the data collected, watch the replay of our most recent "Thirst for Knowledge" webinar "Controlling HABs at Lake Hopatcong” hosted by Dr. Fred Lubnow, Limnologist and Director of Aquatic Resources at Princeton Hydro. The dedicated team at Princeton Hydro provides environmental and engineering consulting services for water quality monitoring, HAB mitigation, and stormwater management projects at Lake Hopatcong.