The North Anna and Upper Pamunkey Branches, including Terry’s Run, of Lake Anna in Orange, Louisa and Spotsylvania counties are experiencing a harmful algae bloom (HAB). The public is advised to avoid contact with specific areas of the lake until algae concentrations return to acceptable levels. 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 Harmful Algal Bloom map. A status report containing the updated advisory areas may be viewed at Lake Anna HAB Status Report 7.15.22.
Samples results provided on July 14 from collections on July 7 indicated that at six locations in the North Anna and Pamunkey Branches, swimming advisories are necessary due to unsafe levels of cyanobacteria, which have the potential to produce toxins. 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. Activities such as boating may continue with proper precaution in advisory areas. Follow-up monitoring above Route. 208 on the lake is planned (weather permitting) for the first week of August.
The samples collected at the Lake Anna State Park beach indicated cyanobacteria densities were at acceptable levels and do not necessitate a swimming advisory. Cyanobacteria and cyanotoxins were detected at this site, but were well below safe swimming levels.
The sections of the lake currently under advisory:
Pamunkey Branch – Upper (including Terry’s Run) and Middle
- Upper – From the upper inundated waters of the Pamunkey to the confluence with Terry’s Run
- Terrys Run – from the upper inundated waters of Terry’s Run to the confluence with the Pamunkey Branch
- Middle – From the confluence of Terry’s Run with Pamunkey Branch to Rt. 612 (Stubbs Bridge)
North Anna Branch – Upper and Middle
- Upper – From the upper inundated waters to the Rt. 522 Bridge.
- Middle – From the Rt. 522 Bridge, to include Rt. 719 (Holladay Bridge), to Lumsden Flats at Rose Valley Dr.
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, people should:
- Avoid contact with any area of the lake where water is green or an advisory sign is posted, WHEN IN DOUBT, STAY OUT!
- 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 Harmful Algal Bloom Hotline at 1-888-238-6154 if you suspect you experienced health-related effects following exposure to a bloom.
- Visit SwimHealthyVA.com to learn more about harmful algae blooms or to report an algae bloom or fish kill.
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 continue to monitor water quality in the lake. In general, advisories will be lifted following two consecutive test results with acceptable levels for algal cell counts and/or toxin concentration. An advisory may be lifted or maintained at the discretion of the health department. For example, after one test an advisory may be lifted if results are within safe levels for swimming if other information indicates exposure or human health risk is low.