SCDES Issues Recreational Advisory for J. Strom Thurmond Lake in McCormick County

FOR IMMEDIATE RELEASE:
Nov. 26, 2025

COLUMBIA, S.C. — The South Carolina Department of Environmental Services (SCDES) today issued a Recreational Advisory for a cove of J. Strom Thurmond Lake in McCormick County after identifying the presence of a harmful algal bloom (HAB). The cove is located off Yacht Club Drive in Plum Branch.

SCDES was notified of a potential HAB by the U.S. Army Corps of Engineers (USACE) on November 20.  Water samples collected from the area on November 24 indicated the presence of cyanobacteria capable of producing cyanotoxins. Laboratory analysis of these samples returned concentrations exceeding the State’s recreational water quality standard for the cyanotoxin microcystin. The U.S. Environmental Protection Agency names microcystin as a potent liver toxin and possible human carcinogen. SCDES has been coordinating and communicating with USACE.

Harmful algal blooms (HABs) are a common occurrence in natural bodies of water, most likely to occur in South Carolina in late spring to early fall when water temperatures are warmer and there is increased sunlight. They can persist for several weeks. These blooms can look like bright green spilled paint or blue-green discoloration of the water. With cooler temperatures, heavy winds, and rain, these blooms may begin to break up and die off. 

If water appears discolored or if an algae bloom is present, SCDES advises, “when in doubt, stay out.” 

For more information, contact SCDES’s Bureau of Water at 803-898-8374. If calling after hours, please leave a message that can be returned. For additional information about harmful algae in South Carolina, visit the SCDES HABs webpage and Algal Bloom Monitoring Map.

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