Harmful Algal Blooms - FAQ

  • What causes HABs?

    HABs occur when algae grow out of control. Excess nutrients, temperature, water circulation, and wind may contribute to HABs, but how these factors come together to create an algae bloom is not well understood. 

  • How do you prevent HABs?

    Homeowners can reduce fertilizer use and properly maintain their septic systems. Additionally, maintaining the 25-foot vegetated buffer plays an important role in absorbing nutrients before they enter the water. Washing boats before entering new waterbodies can prevent the spread of HABs.

  • When does EPD sample and test for HABs?

    The sampling protocol is triggered by visual observation of a suspected bloom.  EPD performs visual monitoring on the main channel.  If spatial and/or temporal extent of bloom is significant, then samples are collected and sent to Georgia College and State University for identification, enumeration, and toxin analysis.  If cyanotoxins are present at toxic levels (8 ug/L Microcystin or 15 ug/L for Cylindrospermopsin), then GA DNR or lake managers will issue swimming advisories. Swim advisory will remain in effect until the bloom dissipates.  

  • Is drinking water in surrounding areas affected?

    When EPD is notified of a HAB in a waterbody that sources drinking water, we contact the nearby drinking water utilities and share information. Conventional water treatment consists of several steps, including coagulation, filtration, chlorination, and these processes generally remove cyanobacterial cells and low levels of cyanotoxins. Severe blooms require proactive planning and active management to reduce the risks of cyanotoxins in finished drinking water.

  • How do HABs go away?

    HABs are typically observed during warmer, drier months, and can persist for several weeks. Cooler temperatures, heavy winds, and rain can contribute to HABs breaking up and dying off. Most HABs eventually disappear on their own, naturally. 

  • How do I report possible HABs?

    If you see what appears to be a large HAB, please contact the lake manager immediately (which could be the US Army Corps of Engineers, Georgia Power, Tennessee Valley Authority, Georgia State Parks, etc.).  Also, send an email to [email protected] with the date and time of observed bloom, waterbody name, location, GPS coordinates if possible, and photographs attached.

  • To whom do we report any illness that humans or dogs get from a HAB?

    Report HAB-related illnesses in humans to Department of Public Health Epidemiology 24/7 Public Health Report Line | 866-PUB-HLTH (866-782-4584).