Photo Courtesy of Smith Mountain Lake Association (SMLA)
Understanding Harmful Algal Blooms
The shimmering waters of Smith Mountain Lake are a beloved attraction for residents and tourists alike, but recent years have shown that these picturesque waters aren’t immune to environmental challenges. Harmful algal blooms (HABs) have started to make periodic appearances, disrupting recreational activities and raising concerns about the health of the lake. Keri Green, Chair of the Lake Quality Council with the Smith Mountain Lake Association (SMLA), offers valuable insights into these blooms and how the community is working to manage and prevent them.
What are harmful algal blooms?
HABs occur when cyanobacteria — commonly known as blue-green algae — multiply rapidly, often due to a combination of nutrient-rich water and favorable weather conditions like high temperatures and stagnant water. The presence of nitrogen and phosphorus, primarily from agricultural runoff, fertilizers and improperly treated sewage, fuels these blooms. As the climate warms, HABs are becoming a more frequent issue across U.S. lakes, including Smith Mountain Lake, where the water stays warmer for longer periods each year, creating prime conditions for these algae to flourish.
These blooms aren’t just an aesthetic nuisance; they pose risks to human and animal health. Some HABs release toxins that can irritate the skin, cause gastrointestinal symptoms, and, in severe cases, lead to respiratory issues. Pets and livestock that encounter contaminated water can also become seriously ill or die, as documented by public health organizations like the CDC and EPA.
Photo Courtesy of SMLA
The impact at SML
According to Green, 2023 marked a significant challenge for Smith Mountain Lake, with HABs prompting the Virginia Department of Health to issue swimming advisories in the Blackwater arm of the lake. “The blooms were classified as harmful not because of toxicity but because of the high concentrations of cyanobacteria,” she explains. While no fish kills or animal illnesses were reported, the advisories highlighted the need for better monitoring and prevention strategies.
Interestingly, 2024 saw a significant improvement, with no citizen reports of blooms and fewer nutrients entering the lake due to lower early-summer rainfall. However, Green emphasizes that the events of 2023 remain puzzling. The Virginia Department of Environmental Quality (DEQ) and Virginia Tech Water Resources Research Center are currently investigating the bloom dynamics with state funding allocated for this purpose.
Photo Courtesy of SMLA
Collaborative monitoring & public education
Smith Mountain Lake has a long history of water quality monitoring, led by Ferrum College’s program, but HAB-specific monitoring remains limited. Green indicates that samples for HABs are only collected when credible reports are submitted to the Virginia Department of Health. SMLA launched new initiatives, such as the Be HAB Aware campaign, to educate residents on recognizing and reporting potential blooms. The SMLA also collects water weekly from dock locations and monitors for the presence of certain cyanobacteria through a program called Dock Watch. Additionally, the DEQ also conducts monthly monitoring for numerous parameters, including for cyanobacteria.
Public education efforts play a key role in HAB management. Green highlights the work of the Smith Mountain Lake Water Quality Alliance, which brings together residents, businesses and officials to disseminate important information about water quality. Clear communication helps reduce fear and ensures residents understand the lake’s current status and how to respond if a bloom is spotted.
How residents can help
Preventing HABs requires a community effort. Green encourages lake residents to adopt practices that reduce nutrient runoff. “Simple actions like reducing or stopping the use of phosphorus-containing fertilizer, planting a buffer garden to intercept nutrients before they wash into the lake, making sure septic systems are regularly pumped and functioning properly, and cleaning up pet waste can make a big difference,” she says. These steps reduce the nutrient load entering the lake, depriving cyanobacteria of the conditions they need to grow unchecked.
Future challenges
While the lake community has made significant strides, Green acknowledges that challenges remain. “We can’t think about controlling HABs until we fully understand the conditions that allow them to occur,” she explains. Addressing nutrient loads and studying the watershed dynamics are top priorities for the council. Smith Mountain Lake Association is also advocating for sustained state funding to enhance monitoring efforts, as delays in receiving test results have caused frustration and uncertainty among residents.
State partnerships with Virginia Tech and the DEQ are critical to improving response times and implementing long-term solutions. Green also points to collaboration with Lake Anna, another Virginia lake facing similar issues, as an example of coordinated advocacy for better funding and monitoring across the region. By aligning efforts with regional lakes and state institutions, the partnership aims to standardize monitoring practices and ensure that lessons learned from one water body can benefit others.
Smith Mountain Lake’s experience with HABs reflects broader national trends. HABs are an emerging environmental and public health issue, with states across the U.S. reporting increased occurrences. According to the CDC, harmful blooms led to advisories and closures in at least 34 states in 2022, underscoring the importance of tracking, monitoring and preventing these blooms nationwide. In states bordering oceans, HABs cost communities millions of dollars annually, impacting tourism, property values and public health.
Despite the challenges, the Smith Mountain Lake community remains optimistic. “Our residents are the first eyes on the lake,” says Green, “and with everyone’s help, we can reduce the risk of future blooms and protect the lake we love.”
For more information on how to stay safe and prevent harmful algal blooms, visit smlassociation.org/HAB or the Virginia Department of Health’s Harmful Algal Bloom resources. ✦