**Latest Updates: Water shield plants, non-indigenous, non-flower blooming invasive species, have become prominent, especially in the Cove. A project is underway with Lake Harmony Group and LHWPG to remove the water shield plants. Read update in Reports.**
LHWPG Current Lake Assessments and Reports
While years ago, Lake Harmony was 31 feet deep in some areas, the depth and volume was decreasing rapidly because storm sewer sediment was draining into the lake, along with accumulating leaf debris, construction waste, vegetative growth and residues from human activity. Action needed to be taken to save the lake.
Enabled by your donations and community support, initiatives with 1-Clean-Flo International and 2-Natureworks have helped to slow down this deterioration of the lake in recent years. The current reports for these initiatives are linked below.
1. Clean-Flo International Oxygenation-Inversion System Program
The Clean-Flo system oxygenates and mixes the entire lake using bubblers to accelerate the decomposition of lake bottom contamination. The system has been operating since June 2018 following a preliminary scan in 2017. Since that preliminary scan:
>> The lake's average depth has increased from 7.7 feet to 8.2 feet.
>> The maximum depth has increased from 14.5 feet to 15.4 feet.
>> The lake's volume has increased by 23M gallons.
>> A total of 102,414 cubic yards of muck has been digested. This is equal to the effective removal of 7,600 full dump trucks.
>> The oxygenation system has achieved consistent full oxygenation of the water column, which is essential for invevertebrates and fish to flourish.
Summary
Clean-Flo’s oxygenation-inversion system and bioaugmentation program continue to achieve results in Lake Harmony. Between 2021 and 2022, the lake experienced:
• Increases in maximum depth, average depth, and volume of the lake; and
• Improvement in the fishery and general recreational use.
The increases in depth and reduction of sediments are due to the decomposition of soft organic sediment and, by extension, show a continued hardening of the bottom. These improvements are due to the benefits of the oxygenation and mixing of the lake by the oxygenation-inversion system, and to the continued bioaugmentation program.
The overall increase in volume and corresponding sediment reduction have amounted effectively to tremendous removal of material from the lake that through conventional dredging might have cost millions of dollars. Clean-Flo's biodredging approach to sediment reduction has been proven effective and the unit cost of the approach has likely been a small fraction of dredging costs.
Recommendations
Clean-Flo recommends that Lake Harmony continue to operate the oxygenation-inversion system and follow an annual bioaugmentation program of product applications. Continued applications are needed in the middle area of the lake due to the more extensive soft sediments in that area. As future progress scans are performed, the application strategy will be revisited from year-to-year to account for the response of the lake in certain regions and quantities applied.
Follow the links below to access the 2021 and 2022 Lake Harmony Biobase Scan reports from Clean-Flo International.
Clean-Flo Lake Harmony Biobase Scan Oct. 2022
Clean-Flo Lake Harmony Biobase Scan Oct. 2021
Learn more about the Clean-Flo technology on their website: www.clean-flo.com
2. Natureworks Vegetative Treatment Program
Natureworks is an Environmental Consulting Firm specializing in Aquatic Plant Management. They assess the invasive plant and algae growth and treat the lake as needed, first conducting surveys of vegetative growth all around Lake Harmony, and then providing reports on lake depth and volume. These reports are used to develop a strategy for treating the lake in the most effective way to reduce the vegetative growth while improving overall lake health.
Natureworks Treatments in 2023
On 7/19/2023, Natureworks successfully treated 32.22 acres of submersed weed growth comprised of Bladderwort, Floating Leaf Pondweed, Thinleaf Pondweed, and American Pondweed. The lake was closed to boat traffic after 5 pm until Thursday morning - thank you for your compliance during this time. Natureworks posted restriction signs on the shoreline, notified Split Rock and LHA also made notifications.
According to the applicator's field logs, “Submersed weed growth was targeted for control during the visit. Plant growth should begin to die back and show signs of control within a week. Also, we observed an increase in algae density during today’s visit, likely due to the recent spike in temperatures. NOTE: NatureWorks returned to Lake Harmony on August 17, 2023 to treat the algae.
We would like to thank all involved for their compliance in keeping boats off the lake during our treatment. This aids in not only treatment effectiveness but applicator safety. We will schedule a follow up visit in several weeks to view results."
As we learn more, we'll continue to actively update you here on https://www.lhwpg.org.
Longer Term Lake Treatment Plan Initiated in the Cove on October 2, 2023
A 2-3 year program to reduce the Water Shield invasive plants around the private and public dock areas was kicked off on October 2, 2023 in the Cove. The treatments will occur each late September/early October for the next several years in varying areas of Lake Harmony. Once this specific treatment occurs and the water shield plants die at the root, the mass will float to the surface (emitting some odor). The mass subsequently will be skimmed away and removed, dried along the shoreline and possibly reused as soil in some capacity.
2022 Treatment Review
Natureworks Lake Harmony Survey 6.21.2022.pdf
The Natureworks survey data and report from June 2022 is linked above. In 2022, the lake was treated five times. We had terrific compliance each time, thank you! Thank you everyone for discontinuing boating and lake activities until the following morning. About 20% of the lake area requires treatment each year.
The Natureworkds June 21, 2022 Survey summary email report provided stated that “Overall the lake looks good. Water quality testing results as well as clarity are very good. Plant growth is beginning along the shoreline in the shallow cove areas.” A map is provided in the survey report and also shown below. This map shows Pondweeds and Bladderwort growth in the Split Rock cove and American Pondweed toward the shoreline in the middle and end of the lake by Nicks Lake House.
To allow all species of weed growth to be up and ready for treatment, Natureworks stated they would be approximately four weeks out from June 21 to be ready for treatment. Treatment cannot be scheduled weeks or months in advance due to changing conditions within the lake as well as weather. Natureworks posts treatment notices as close to the week prior to treatment as possible.
Moving forward, discussions regarding additional floating weed management will be conducted and a plan will be discussed. Following previous treatments, floating boggs developed, so methods to address this in the future will be evaluated. Efforts to keep the upper end (Cove) of Split Rock clear were discussed.
- When Natureworks employees treat Lake Harmony, they post their Herbicide Treatment Signs around the lake (shown below). Natureworks also provides a Fact Sheet about the treatment. Thank you for reviewing our Events and Important Messages.
Read more about Natureworks on their website: www.natureworkscwa.com.