Harmful Algae Bloom Advisories Remain in place for North Anna and Upper Pamunkey Branches of Lake Anna; In Orange, Louisa and Spotsylvania Counties

FOR IMMEDIATE RELEASE – October 19, 2021
Media Contact: Brookie Crawford, Brookie.Crawford@vdh.virginia.gov

Harmful Algae Bloom Advisories Remain in place for North Anna and Upper Pamunkey Branches of Lake Anna; In Orange, Louisa and Spotsylvania Counties
Public Advised to Avoid Water Contact within these Locations of the Lake

Richmond, Va. – The North Anna and Upper Pamunkey Branches, including Terry’s Run, of Lake Anna in Orange, Louisa and Spotsylvania counties are continuing to experience a harmful algae bloom (HAB). The public is advised to avoid contact with the lake in this area. Some harmful algae, called cyanobacteria, can cause skin rash and gastrointestinal illnesses, such as upset stomach, nausea, vomiting and diarrhea. The area to avoid can be seen on an interactive map at the Algal Bloom Surveillance Map. A status report containing the updated advisory areas may be viewed at Lake Anna Status Report 10.18.21.

Results of samples collected October 12 indicated that swimming advisories continue to be necessary due to unsafe levels of potential toxin producing cyanobacteria segments of the North Anna and Pamunkey Branches. People and pets are advised to avoid swimming, windsurfing and stand-up-paddle-boarding, as well as other activities that pose a risk of ingesting water.

The samples collected downstream at the confluence of the two branches, at the Lake Anna State Park beach, and at the 208 bridge indicated cyanobacteria densities were at acceptable levels and do not necessitate a swimming advisory.

The sections of the lake currently under advisory (no change in advisory extents compared to September):

Pamunkey Branch

  • From the upper inundated waters of the Pamunkey arm of the lake downstream to the 612 Bridge. Includes Terry’s Run.

North Anna Branch

  • From the upper inundated waters of the North Anna arm of the lake downstream to above the confluence with Pamunkey Branch above Goodwins Point. Does not include “the Splits.”

While overall cyanobacteria densities and detectable levels of cyanotoxins were lower, requirements to lift advisories within these areas of Lake Anna could not be met from the October 12 sample event. The HAB Task Force discontinues response sampling in October, when the recreational (swimming) season concludes as temperatures begin cooling in natural waters.

Algae blooms can occur when warm water and nutrients combine to make conditions favorable for algae growth. Most algae species are harmless, however, some species may produce irritating compounds or toxins. Avoid discolored water or scums that are green or bluish-green because they are more likely to contain toxins.

To prevent illness:

  • Avoid contact with any area of the lake where water is green or an advisory sign is posted,


  • 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.
  • Seek medical/veterinarian care if you or your animals experience symptoms after swimming in or near an algal bloom.
  • Properly clean fish by removing skin and discarding all internal organs, and cooking fish to the proper temperature to ensure fish fillets are safe to eat.
  • Contact the Virginia Harmful Algal Bloom Hotline at 1-888-238-6154 if you suspect you experienced health-related effects following exposure to a bloom.

The blooms which are present in the lake may persist into the fall and possibly winter months. While the current cyanobacteria bloom could reach safe levels at some point during the fall and winter months, resources are not available for the Task Force to continue the monitoring in off-season months in order to formally lift the advisories in the 2021 year. Activities where full body submersion is not likely to occur, such as fishing, boating, flat-water kayaking, can continue with appropriate caution.

The Virginia Department of Health (VDH) and the Virginia Harmful Algal Bloom Task Force, which includes the VDH, the Virginia Department of Environmental Quality, and the Old Dominion University Phytoplankton Laboratory, will resume response monitoring efforts in May 2022, weather permitting.

For more information visit www.SwimHealthyVA.com.

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