The Lake Hartwell Association Addresses Harmful Algal Blooms on Lake Hartwell

As the Lake Hartwell Association (LHA), we proudly represent the interests of residents adjacent to, and those who use and benefit from, Lake Hartwell. Our reach extends across the entire lake, encompassing both states and all six counties. We serve as a unified voice, advocating for the protection of our lake’s water quality, quantity, and safety. This commitment is why we recently hosted an essential presentation from the South Carolina Department of Environmental Services (SCDES) to address ongoing concerns about harmful algal blooms (HABs).

Understanding Harmful Algal Blooms (HABs)

During our recent presentation, Emily Bors, SCDES’s Harmful Algal Bloom Coordinator, provided invaluable insights into HABs. She explained that these blooms occur when microscopic organisms called phytoplankton overgrow under specific conditions like abundant nutrients, warm temperatures, increased light, or stagnant water. It’s important to understand that while phytoplankton are naturally occurring, some blooms, particularly those from cyanobacteria, can produce toxins harmful to humans, animals, and the environment.

• Key toxins of concern: The primary freshwater toxins that concern us and are monitored by SCDES are microcystins and cylindrospermopsin, which can affect the liver. SCDES issues recreational advisories when levels of these toxins exceed state standards.
• Other potential issues: Beyond toxins, HABs can also lead to unpleasant tastes and odors in the water, cause decreased oxygen levels that can result in fish kills, and certain algal species can even cause physical harm.

Lake Hartwell’s Current Situation

SCDES has been diligently monitoring Lake Hartwell since reports of a HAB emerged.

• Initial reports: We first became aware of potential issues in late April.
• Confirmed species: Analysis has confirmed the presence of Dolichospermum, a species known to potentially produce multiple toxins. Microcystis algae have also been identified, though at lower concentrations.
• Toxin levels: Crucially, while the potentially toxin-producing species is present in the lake, the toxin levels detected thus far have remained below the state’s recreational advisory limits. This is reassuring, but continued vigilance is key.
• Monitoring and Communication: SCDES utilizes a comprehensive web application (which they’re trying to consistently call the HAB Monitoring Web Application to avoid confusion with phone apps!) to provide real-time updates. Currently, Lake Hartwell is under a “HAB Watch.” This means SCDES has identified the presence of a potential toxin-producing species, but toxin levels are below the state’s advisory threshold. We, along with SCDES, advise caution and recommend avoiding direct contact with any visible bloom.

Your Questions Answered

We know our members and the community have many questions, and SCDES addressed several of them during the presentation:

• How long will the bloom last? Unfortunately, there’s no definitive answer. HABs can persist for days, weeks, or even months, influenced by environmental factors such as temperature, light, nutrient availability, and wind/wave action. SCDES will continue monitoring until the bloom dissipates.
• Can my dog swim in the lake? We advise extreme caution with pets. Dogs are often attracted to the smell and appearance of algal mats and are more prone to ingesting water and licking their fur, increasing their risk of exposure to any toxins.
• Can I swim in the lake? If you are in an area where no bloom or discoloration is visible, and you feel comfortable, swimming is generally considered low-risk. However, we strongly advise avoiding direct contact with any visible bloom accumulation. The bloom can move with winds and waves, so conditions can change rapidly.
• Is our drinking water safe? Most drinking water facilities’ normal treatment processes are effective at removing low levels of these toxins. SCDES has been in contact with the two major drinking water facilities on the South Carolina portion of Lake Hartwell, and they are ensuring their treatment processes are effective.
• Where are the nutrients coming from? Nutrients can enter the lake from various “non-point sources.” These include fertilizers used on lawns, agricultural runoff from upstream areas, pet waste, and reduced natural shoreline buffers that normally help absorb runoff.
• Does heat promote growth? Generally, warmer temperatures do favor the growth of cyanobacteria.
• What can individuals do to minimize annual impact or spread? While we can’t pinpoint the exact cause of this bloom, reducing potential nutrient input is crucial. Homeowners can help by avoiding over-fertilizing their lawns, picking up grass clippings, properly managing pet waste, and ensuring their septic systems are well-maintained and functioning efficiently, especially if they are close to the lake.
• Can anything neutralize or kill the algae? There are treatment options, such as algicides, but these are often considered as a last resort in large water bodies.

For a more in-depth understanding of this important issue, we encourage you to watch the entire recorded conversation on YouTube: SCDES Lake Hartwell HAB Update – May 21, 2025

We hope this information helps you make informed decisions when enjoying Lake Hartwell. Your passion for Lake Hartwell is our driving force. As the heart of the LHA, our members play an active role in protecting and preserving this cherished natural resource for generations to come. Your membership directly fuels our vital efforts in advocating for water quality, quantity, and safety, as well as supporting crucial lake management, outreach, and community initiatives.

We strongly encourage everyone who cares about Lake Hartwell to visit our website and social media channels to learn more about our work and to consider becoming a member. You can become a member for as low as $50 a year and become an essential part of sustaining the vital activities we undertake for the health of our beloved lake. Your support is absolutely essential to our mission

Important Timestamps and Information from the Presentation

For those who wish to review specific points from the presentation, here’s a helpful list of timestamps:

• 0:00-0:31: Introduction of Terry Jackson, President of the Lake Hartwell Association, and our organization’s mission and purpose.
• 0:37-0:49: Our vital interest in protecting Lake Hartwell’s water quality, quantity, and safety.
• 2:09-3:24: Introductions of Emily Bors (SCDES Harmful Algal Bloom Coordinator) and other key SCDES team members.
• 4:27-5:36: A detailed explanation of what Harmful Algal Blooms (HABs) are and why they can be dangerous.
• 5:36-6:30: Discussion of specific freshwater toxins (microcystins, cylindrospermopsin, saxotoxins, and anatoxins) and South Carolina’s recreational advisory standards.
• 7:20-8:04: Identification of Dolichospermum as the primary algal species observed in Lake Hartwell.
• 8:11-9:07: SCDES’s step-by-step process for investigating and analyzing reported algal blooms.
• 9:07-10:23: A clear explanation of the SCDES HAB Monitoring Web Application and its different advisory tiers (Reported Sighting, Monitoring Station, HAB Watch, and HAB Advisory).
• 11:21-12:39: A timeline of SCDES’s dedicated monitoring and sampling efforts on Lake Hartwell.
• 12:52-13:26: The reassuring update on the low toxin levels found in Lake Hartwell samples.
• 13:52-14:24: Key recommendations for safe recreation on the lake and SCDES’s commitment to ongoing monitoring.
• 14:53-16:40: Addressing many of the frequently asked questions about the bloom’s duration, pet safety, and human swimming.
• 16:40-17:13: Important information regarding the safety of our drinking water.
• 17:13-17:40: SCDES’s contact information for reporting new sightings or asking further questions.
• 17:46-end: The comprehensive Question and Answer session from the presentation.