7/19/2025
BOATING ADVISORY LIFTED 7/21/25: Keatons Lake is open to boating traffic, Keatons Run Boat Launch area is closed due to debris, members are advised to use caution. The Main Lake is OPEN TO REGULAR BOATING TRAFFIC.
Keatons Lake HAB Update and Response Summary:Keatons Lake IS OPEN for Recreational Use
WITH A SWIM ADVISORY FOR KEATONS RUN BOAT LAUNCH AND INLET AREA DUE TO ELEVATED
E. coli CONCENTRATIONS .
The July 7 samples and the July 15 samples were both below any closure or advisory threshold for PTOX concentration in the LOWA Harmful Algal Bloom Response Protocol. LOWA can reopen Keatons Lake to recreational use.
FURTHER TESTING: E. coli samples for Keatons lake were collected on 07/17/2025 at Cumberland Beach and at the Keaton’s Lake Boat Launch.
Results:
Cumberland Beach (34.5 CFU/100mL) OPEN FOR USE
Keatons Run Boat Launch (727 CFU/100mL): SWIM ADVISORY FOR BOAT LAUNCH AND INLET AREA.REFERENCE MAP FOR AREA UNDER SWIM ADVISORY.
*While KEATONS BOAT LAUNCH AND INLET AREA are open, members swim and engage in water activities at their own risk until test results confirm lower E. coli concentrations at these locations. This advisory is in place to help protect the health and safety of all users. E. coli concentrations were elevated above the Virginia Department of Health recommended beach threshold (235CFU/100ml).
KEATONS LAKE HAB CONDITIONS UPDATE: A second set of water samples were collected by LOWA staff on July 15. Results were received July 17. Potentially toxigenic bacteria (PTOX) at all sample sites were less than 40 cells/mL.
The July 7 samples and the July 15 samples were both below any closure or advisory threshold for PTOX concentration in the LOWA Harmful Algal Bloom Response Protocol.
Consistent with the protocol, we can now reopen Keatons lake to recreational use WITH A SWIM ADVISORY FOR KEATONS RUN BOAT LAUNCH AND INLET AREA DUE TO ELEVATED E. coli CONCENTRATIONS.
July 16, SOLitude Lake Management conducted the second phase of the two-part algaecide treatment.
We appreciate your patience and cooperation as we work to ensure the lake is safe for use. We will provide another update as soon as new E. coli test results are available.
Per LOWA HAB Response Plan, reopening Keatons Lake requires:
- Waiting at least 48 hours after treatment for product efficacy.
- Conducting post-treatment testing to confirm reduced PTOX levels.(samples collected 7/7, Results 7/16. Potentially toxigenic bacteria (PTOX) at all sample sites were less than 40 cells/ml.)
- Conducting a second round of testing approximately one week later. (samples collected 7/15, Results were received 7/17 and all sample sites were less than 40 cells/ml.)
- Ensuring all sample results fall below closure and advisory thresholds. The July 7 samples and the July 15 samples were both below any closure or advisory threshold for PTOX algae density in the LOWA Harmful Algal Bloom Response Protocol. Consistent with the protocol, we can now reopen Keatons lake to recreational use.
LOWA HAB Response Protocol:
Lake Closure- threshold exceeding PTOX 50,000 cells/mL .
Lake Advisory- threshold exceeding PTOX 10,000 cell/mL.
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RESPONSE SUMMARY:
Lake of the Woods Association follows a Harmful Algal Bloom Response Protocol, which outlines monitoring and treatment procedures from June through September. As part of this protocol, regular algae identification testing is conducted to track concentrations of potentially toxigenic cyanobacteria (PTOX).
The response plan includes the following thresholds:
Lake Advisory- PTOX concentrations exceed 10,000 cell/mL.
Treatment recommended when PTOX concentrations reach 20,000–50,000 cells/mL.
Lake closure triggered when PTOX concentrations exceed 50,000 cells/mL.
Below are the most recent testing results for Keatons Lake:
May 28, 2025 – PTOX average = 3810 cells/mL, highest single site PTOX = 7800, total algal density average = 5450 cells/mL
June 13, 2025 – PTOX average = 4800 cells/mL, highest single site PTOX = 6400, total algal density average = 6533 cells/mL
June 19, 2025 – PTOX average = 2467 cells/mL, highest single site PTOX = 3700, total algal density average = 9690 cells/mL
June 25, 2025 – PTOX average = 48,300 cells/mL, highest single site PTOX = 89,900 cells/mL, total algal density average = 48,300 cells/mL
July 8, 2025 (1st post-treatment sample) – PTOX average = less than 40 cells/mL, highest single site PTOX = less than 40 cells/mL, total algal density average = 3570 cells/mL
July 16, 2025 (2nd post treatment sample) – PTOX average = less than 40 cells/mL, highest single site PTOX = less than 40 cells/mL, total algal density average = 27,900
As indicated above in the testing results, we experienced a significant spike in PTOX levels between June 19 and June 25—leaping from the “green” category (below 10,000 cells/mL) to well into the “red” category (above 50,000 cells/mL), which requires immediate lake closure. Referencing the Water Quality Testing Parameters: Algal Blooms in the Response Protocol.
This sudden increase is likely the result of several consecutive weather events, including heavy rainfall (which introduces nutrient runoff into the lake) followed by a stretch of high temperatures—ideal conditions for algae to proliferate rapidly.
Although the June 19 sample showed relatively low PTOX levels, in anticipation of potential growth and the upcoming holiday, we proactively scheduled SOLitude Lake Management to perform a treatment on July 2, 2025, with a follow-up treatment 10–14 days later which occurred on July 16.
According to SOLitude, the HAB treatment product remains effective for approximately 48 hours, so scheduling too early would allow time for regrowth before the July 4th weekend.
Despite our proactive planning, the rapid rise in cell counts between testing dates surpassed our expectations and required immediate closure.
Next Steps and Reopening Protocol:
Per our HAB Response Plan, reopening Keatons Lake requires:
- Treatment Application (Completed July 2)
- Wait 48 Hours for treatment to take effect.
- Post-Treatment Testing to confirm reduced levels- 7/7/25 samples taken. July 16 test results were received. Potentially toxigenic bacteria (PTOX) at all sample sites were less than 40 cells/mL.
- Follow-Up Testing one week later-The second set of samples were collected 7/15/25. Results were received 7/17/25. Potentially toxigenic bacteria (PTOX) at all sample sites were less than 40 cells/mL.
- Verification that levels are below closure and advisory thresholds-The July 07 samples and the July 15 samples were both below any closure or advisory threshold for PTOX algae density in the LOWA Harmful Algal Bloom Response Protocol. Consistent with the protocol, we can now reopen Keatons lake to recreational use.
We understand this is disappointing for members, but we remain committed to prioritizing public health and safety in accordance with our established environmental protocols.
We will continue to keep the community informed as we monitor progress and await post-treatment results.
To follow our Beach and Lake Statuses which includes water testing results click HERE.
To Learn More about Harmful Algal Bloom (HAB) and FAQ about HAB explore the Virginia Department of Health (VDH) Swim Healthy, Virginia webpage Click HERE.
To Access the Keatons Lake Harmful Algal Bloom Response Protocol Click HERE
