September 22, 2023
Harmful Algae Bloom Advisory Issued for Upper Pamunkey Branch; Upper and Middle North Anna Branch Advisories on Lake Anna Remain in Place
Public should avoid swimming in areas under advisory
RICHMOND, Va. – The Upper Pamunkey along with the Upper and Middle sections of North Anna Branch of Lake Anna in Louisa County is experiencing a harmful algae bloom (HAB). The public is advised to avoid contact with this specific area of the lake until algae concentrations return to acceptable levels. Toxin results for samples are pending and should be available next week. The status report will reflect those updates (see link below). 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 based on samples collected on September 19 may be viewed at Lake Anna HAB Status Report 9.22.2023.
The sections of the lake currently under a swimming advisory due to unsafe levels of cyanobacteria:
- Upper Pamunkey Branch (advisory issued 9/22/23)– From the upper inundated waters of Pamunkey Branch to Runnymede Park
Advisories which remain in place:
- Upper North Anna Branch –From the upper inundated waters of the North Anna arm of the lake downstream to the Rt. 522 Bridge.
- Middle North Anna Branch – From the Rt. 522 Bridge, to include Rt. 719 (Holladay Bridge), to Lumsden Flats at Rose Valley Dr.
Results for the Middle North Anna Branch were acceptable (pending toxin results). If toxin results are acceptable, this is the first of two samples required to lift the advisory.
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 9.22.2023. To lift advisories, there must be two acceptable samples collected at least 10 days apart. District health departments may accept results for samples collected less than 10 days apart at their discretion. The next sampling date is planned for the week of September 27, 2023 (weather permitting).
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.
For more information visit www.SwimHealthyVA.com.