October 17, 2023
Media Contact: Brookie Crawford, brookie.crawford@vdh.virginia.gov
Lake Anna Harmful Algae Bloom Advisory Lifted for Middle North Anna Branch
Advisory Remains in effect for the Upper North Anna and Upper Pamunkey Branches
RICHMOND, Va. – Effective immediately, the Virginia Department of Health (VDH) is lifting the harmful algae bloom (HAB) advisory for the Middle North Anna Branch of Lake Anna in Louisa County. However, the HAB advisory for the Upper North Anna and Upper Pamunkey branches remains in effect. A status report containing the updated information may be viewed at Lake Anna Status Report 10/16/23.
The Middle North Anna Branch has experienced a HAB since August. Results of samples collected September 19 and October 10 indicated potentially toxic cyanobacteria were acceptable levels allowing the advisory to be lifted.
The Upper North Anna and the Upper Pamunkey branches have also been under a HAB advisory since August. To lift advisories, VDH needs two acceptable samples collected at least 10 days apart. While the October 10 sample results from the Upper North Anna and Upper Pamunkey branches were at acceptable levels, the September 19 sample results were at unsafe levels of cyanobacteria (>100,000 cells/ml). No additional sampling is planned for the remainder of October.
The public is recommended to be aware of and to avoid discolored water or scums which may be present from the upper inundated areas of the inundated waters of North Anna Branch down to the Rt. 522 Bridge and from the upper inundated waters of the Pamunkey Branch to the vicinity of Runnymede Park.
The Virginia Harmful Algal Bloom Task Force suspends response sampling and any active HAB advisories at the end of October each year when the recreational (swimming) season concludes and temperatures begin cooling in natural waters. Algae blooms which are still present in October/November in areas of a waterbody may persist into late fall and possibly winter months. The public should avoid discolored water or scums that are green or bluish-green because they are more likely to contain toxins.
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 efforts in May 2024, weather permitting.
For more information visit www.SwimHealthyVA.com.
# # #