A blue-green algae bloom has turned parts of Lake Allatoona near the Red Top Mountain State Park marina into a streaky, smelly mess, prompting warnings for swimmers and pet owners. The affected coves are coated with what looks like paint on the surface and carry a foul odor, and officials say people should steer clear of getting in or swallowing water in those spots until tests show the bloom has cleared.
In a May 8 advisory, the Cobb County-Marietta Water Authority said Park Marina reported the bloom on May 7, and the utility’s lab is now sampling water at the intake and nearby locations. Cobb County-Marietta Water Authority noted that its treatment processes are operating normally, that treated drinking water is still safe, and that staff will keep a close watch on results and adjust treatment if needed.
Local media quickly amplified the alert. 95.5 WSB reported that the authority is urging people to keep pets away from water that looks discolored or scummy. Officials also cautioned against letting dogs lick algae-contaminated fur or drink from the lake, since pets can become sick very quickly after exposure to toxins from blue-green algae.
Channel coverage from WSB-TV quoted Cobb County-Marietta Water Authority general manager Cole Blackwell describing the surface slick as looking like “spilled paint” and noting the strong odor. Marina staff told reporters that longtime boaters were taken aback by how thick the scum was in shallow coves, and residents were urged to give those pockets of water a wide berth.
What To Look For And How To Stay Safe
Blue-green algae, or cyanobacteria, can form dense mats or surface scums that resemble pea soup or spilled paint, and in some cases they produce toxins that can irritate skin or trigger gastrointestinal or neurological symptoms. The U.S. Environmental Protection Agency advises people to avoid contact with water that has visible scum, keep children and pets away from it, and rinse off promptly with clean water if contact happens anyway. The agency also recommends seeking medical care if anyone develops symptoms after possible exposure.
Will Tap Water Be Affected?
The Cobb County-Marietta Water Authority has stressed that its intakes and treatment plants are positioned upstream of the problem areas and that finished drinking water has not been affected. Cobb County-Marietta Water Authority said it routinely monitors Lake Allatoona and will use lab findings to guide any changes in treatment. This is not a first for the lake: in 2019, a reported dog death linked to a suspected toxic bloom prompted state testing of Allatoona’s waters and underscored how dangerous algal toxins can be for pets and how quickly advisories need to be issued, according to the Atlanta Journal-Constitution.
Why The Bloom Likely Happened
Officials and reporters have pointed to a familiar recipe: warm, still weather and lower water flows, conditions that are typical of pockets of spring drought and can let cyanobacteria collect in quiet, shallow coves. WSB-TV reported that the bloom may hang around until a strong rain or stiff wind breaks it up, and experts note that nutrient levels and water temperature are key ingredients in these kinds of outbreaks. Local agencies plan to keep sampling and posting updates for residents and boaters as results continue to come in.
For questions about drinking water service from the Cobb County-Marietta Water Authority, residents can call the main line at (770) 514-5300. For park or marina issues, Red Top Mountain State Park can be reached at (770) 975-4226. Officials urge people to check for fresh information from health and water authorities before swimming, paddling, or boating in the affected stretches of Lake Allatoona. Anyone who sees additional discolored or scummy water is asked to report it to park staff or the water authority so sampling crews can track the bloom’s spread.
