*** Weekly water quality testing for the 2023 season ended on 9/28/23.***
CURRENT LAKE CONDITIONS
Current Algae Condition Level is YELLOW (see definitions for more information)
Current E. Coli Condition Level is RED (see definitions for more information)
September 28, 2023
Two samples of beach water collected on 9-28-23 contained 326 and 47 MPN E. coli/100 mL. Levels of E. coli in this range are considered high risk in terms of fecal contamination and it is probably unsafe to swim in such conditions.
Lake-wide surveys performed on 9-24, 9-25 and 9-27 showed that detached benthic material (DBM) consisting of filamentous cyanobacteria (confirmed by microscopy) is now within the criteria established for safe exposure. However, DBMs are still present in high numbers in some of the coves (e.g., 13A), and a phytoplanktonic bloom has now developed and is observed in most areas of the lake (water appears cloudy with green material). As a reminder, cyanobacterial growth and blooms may be expected to occur through October. Phytoplankton blooms are accumulations of microscopic cyanobacteria and algae in the mid- to upper surface layers of water and are different than DBMs.
. Based on this information, a moderate risk is likely, but at present no definitive statements can be made about the cyanobacteria, and the evidence does not support a “Warning” notification.
Hence, a continued Warning notification for fecal contamination and the “Caution” notification for cyanobacteria are advised. The next scheduled testing for GAPOA is 5-2-24.
September 21, 2023
Two samples of beach water collected on 9-21-23 contained E. coli/. Levels of E. coli in this range are considered very high risk in terms of fecal contamination and it is unsafe to swim in such conditions.
Lake-wide surveys performed on 9-18 and 9-21 showed that detached benthic material (DBM) consisting of filamentous cyanobacteria (confirmed by microscopy) continues to exceed criteria established for safe exposure.
Hence, continued Warning notifications for both fecal contamination and cyanobacteria are advised. The next and last scheduled testing for GAPOA is 9-28-23 (Thursday).
Updated Friday, September 15, 2023
Two samples of beach water collected on 9-14-23 contained high levels of E. coli, Levels of E. coli in this nge are considered very high risk in terms of fecal contamination and it is unsafe to swim in such conditions. based on lake-wide surveys performed on 9-11, 9-13 and 9-14, detached benthic material (DBM) consisting of filamentous cyanobacteria continues to exceed criteria established for safe exposure.
Hence, Warning notifications for both fecal contamination and cyanobacteria are advised.
The next scheduled testing for GAPOA is 9-21-23 (Thursday).
September 9, 2023
On 9-9-23 the DBM was not observed in the lake, but on 9-10-23 there were observations at various locations. Due to these recent observations we recommend the Red Warning posting.
September 7, 2023
On 9-7-23 (Thursday) during a beach inspection and E. coli sample collection, numerous colonies / accumulations of detached benthic material (DBM) were observed in water around the pier and in water at the beach. Similar DBM (in appearance and color) have been routinely observed in the lake in 2022 and from May 2023 to present and has been identified via microscopy as a filamentous cyanobacterium in the biological Oscillatoriaceae family, which includes toxigenic Microseira (formerly classified as Lyngbya). The DBM was not seen in higher numbers at other locations in the lake later that day but was observed again at the beach and on 9-8-23.
Two samples of beach water collected on 9-7-23 contained 11 and 0 MPN E. coli/100 mL. Levels of E. coli in this range are considered low risk and it is probably safe to swim in such conditions. One of the samples collected on 9-7 contained zero detectable (i.e., < 5 ppb) Microcystins (cyanobacterial toxin); however, at least two species of cyanobacteria continue to be routinely found in surface accumulations at various points around the lake, including the beach. The next scheduled testing for E. coli is 9-14-23.
August 31, 2023
Two samples of beach water collected on 8-31-23 contained 34 and 135 MPN E. coli/100 mL (an average of 85 MPN E. coli/100 mL). Levels of E. coli in this range are considered low risk and it is possibly safe to swim in such conditions. The next scheduled testing for E. coli is 9-7-23 (Thursday).
August 24, 2023
Two samples of beach water collected on 8-24-23 contained 47 and 34 MPN E. coli/100 mL (an average of 41 MPN E. coli/100 mL). Levels of E. coli in this range are considered low risk and it is probably safe to swim in such conditions. The next scheduled testing for E. coli is 8-31-23 (Thursday). Swimmers are reminded to wait up to 48 hours following a precipitation event – the NWS forecast for next week calls for a 60% chance of precipitation on Monday (8/28) and Tuesday (8/29).
A separate report is being prepared on the algae/cyanobacteria in the lake and is forthcoming. In summary, numbers of detached benthic mats and/or planktonic blooms (visible on the surface; consistent with cyanobacteria) have not been observed in high numbers (defined as >1 per 10 sq. meter) in the lake.
The green filamentous algae that accumulate around most of the shoreline this time of year has been drying out/stranded on rocks, sticks, etc. and on the soil of the shallow areas as a result of the receding water level of the lake that has been recently observed.
The “Yellow / Caution” sign for algae/cyanobacteria should remain in place; however, this is the time of year when sudden changes in water quality may occur and so monitoring for A/C will continue.
August 10, 2023
Two samples of beach water collected on 8-10-23 contained 0 and 15 MPN E. coli/100 mL (an average of 7.5 MPN E. coli/100 mL). Levels of E. coli in this range are considered low risk and it is probably safe to swim in such conditions. The next scheduled testing for E. coli is 8-17-23.
August 3, 2023
Samples of beach water collected on 8-3-23 contained an average of 80 MPN E. coli/100 mL. Levels of E. coli in this range are considered low risk and it is possibly safe to swim in such conditions. The next scheduled testing for E. coli is 8-10-23.
July 27, 2023
A sample of beach water collected on 7-27-23 contained an average of 30 MPN E. coli/100 mL. Levels of E. coli in this range are considered low risk and it is probably safe to swim in such conditions.
The current results are lower than the average level of E. coli in beach water in an entire season (2022 avg. = 152 MPN/100 mL) and are similar to results from this time last year (7/28/22 = 74 MPN/100 mL).
Recommend that the Yellow / Caution sign be taken down.
The next scheduled testing for E. coli is 8-3-23.
July 20-22, 2023
Duplicate portions of a sample of beach water from this date suggest posting the
yellow/caution signs for E. coli. Note that E. coli is tested in beach water and not the rest
of the lake; hence, the advisory for E. coli (i.e., fecal contamination) is for beach water
only.
A survey of the entire lake on 7-20-23 did not show an elevated occurrence of
cyanobacteria and the water clarity is relatively high (between 10-11 feet; historically,
values have been approximately 8 feet for the month of July; lower values signify
cloudy/turbid conditions, or water of less “quality”). Hence, conditions are considered
safe in terms of visual assessment of algae/cyanobacteria for the entire lake. To date,
levels of microcystins (cyanobacterial toxins) in beach water have remained
undetectable (i.e., “0”) and similar to E. coli, microcystins are tested in beach water only.
The next survey of the lake for algae/cyanobacteria will occur on 7-21-23 and/or 7-22-
23 and the next testing for microcystins in beach water will occur on 7-22-23.
At the present time, pet owners who allow their dogs to swim in the lake, should consider the following information and take the precautions listed below.
Lake Users: It is highly recommended to wash with fresh water after having contact with the lake water. (Included but not limited to swimmers, recreationals, boaters, fishers, pets, water crafts and water floats.....).
According to the ASPCA:
cyanobacteria is most likely to thrive in bodies of fresh water when the weather is warm (over 75°F) and sunny. Algae intoxications happen more during the summer because weather conditions promote the growth of cyanobacteria.
Some researchers reported that when temperatures became less than 68°F, there were insignificant amounts of blue-green algae in a lake studied in Wisconsin.
The surface water temperature of our lake has been ~70°F the past few days (October 13 to present) ,and continues to decrease with the cooler temperatures that are now occurring this time of year. Some visible phytoplankton accumulation continues to be observed, mostly in the lake's coves, but not to the extent seen in August and September (2020), and visible surface growth is not seen in other areas of the lake.
Recent microscopic analysis of some of the coves' material shows the presence of anabaena and aphanizomenon, which, according to the Maryland Department of Natural Resources are filamentous
cyanobacteria.
It is unknown whether the isolates seen by microscopy from our lake are toxigenic or not -
NOTE: Not all cyanobacteria blooms are toxic and even blooms caused by known toxin producers may not produce toxins or may produce toxins at undetectable levels.
It is expected that anabaena, aphanizomenon and other cyanobacterial populations will be shown to be present year-round in our lake, including "over-wintering" in the lake.
Therefore, we are currently at the CAUTION level.
When in doubt, stay out!
The Virginia Department of Health lists the following things people should do to prevent illness:
· Avoid contact with any area of the lake where water is green or an advisory sign is posted.
· Do not allow children or pets to drink from natural bodies of water.
· Keep children and pets out of the areas experiencing a harmful algae bloom and quickly wash them off with plenty of fresh, clean water after coming into contact with algae scum or bloom water.
· If you or your animals experience symptoms after swimming in or near an algal bloom, seek medical/veterinarian care.
· To ensure fish fillets are safe to eat, properly clean fish by removing skin and discarding all internal organs, and cooking fish to the proper temperature.
· If you suspect you experienced health-related effects following exposure to a bloom, contact the Virginia Harmful Algal Bloom Hotline at 1-888-238-6154. To learn more about harmful algae blooms or to report an algae bloom or fish kill visit www.SwimHealthyVA.com.
435 Greene Acres Rd N, Stanardsville, VA 22973
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