Be HAB Aware at Smith Mountain Lake

Information and Resources about Harmful Algal Blooms and how they are affecting SML.

As anyone who loves Smith Mountain Lake, whether you live here, work here, visit or just pass by, you want to know the latest information about water quality, safe recreation, sampling, reports and any potential for Swimming Advisories. Stay up to date on various initiatives and investigations by visiting our Facebook page, coming to this page often for updates, to stay informed about changing lake conditions.

Using common sense around open waters makes for a fun, exciting, relaxing and smart visit to SML. Wear that PFD, make sure children are always supervised when swimming or on docks, take a Boater Safety course, and be a smart boat operator.

Remember, When in Doubt, Stay Out, is the best advice to follow when swimming in any recreational water. Decisions made to protect the public are the responsibility of the Commonwealth of Virginia, the Virginia Health Department, the Virginia Department of Environmental Quality, and local authorities.  Decisions about whether you, your family and your pets go swimming in any recreational water throughout the state are yours to make, and you should base that decision on all the information the authorities provide.

The Smith Mountain Lake Water Quality Alliance is a group of lake community members made up of business owners, Smith Mountain Lake Association board members, Ferrum College representatives, County emergency management officials, residents, and state officials, all working together to align messaging, provide timely information and help the SML area understand water quality issues.

The Smith Mountain Lake Water Quality Alliance’s number one goal is to reach as many lake users as possible, visitors, guests, and residents with the information we are provided by state and local authorities.

HABs and SML

HABs are not formed by true algae; they’re really an overgrowth of a type of photosynthesizing bacteria, cyanobacteria, which used to be known by the science community as blue-green algae.  The term harmful algal bloom may be a bit outdated but seems to be the most accepted way to refer to these occurrences. Cyanobacteria are naturally occurring microscopic organisms found all over the world, in fresh and sometimes saltwater. Blooms of cyanobacteria often (but not always) discolor the water bright green or blue green and form scum.

A combination of environmental factors, such as the presence of overabundant nutrients, warm temperatures, and a lot of sunlight can encourage a massive increase in the numbers of cyanobacteria in a short amount of time. They have the potential to become harmful because certain species can create toxins, especially when “blooming” and overgrowing. Cyanobacteria HABs can produce multiple toxins, including liver, nerve, and skin toxins, which can affect human and animal health. The toxins can cause rashes, breathing difficulties, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea. Children and pets are most likely to be exposed because they are more likely to ingest water while swimming.

HABs have become more prevalent in U.S. lakes over the past few decades. Smith Mountain Lake has been touted as one of the cleanest lakes in the eastern half of the United States and, until recently, believed to be free of HABs unlike many lakes in the region. Limited observations and sampling over the past six years have revealed spot blooms, but these did not last long enough to be verified through sampling and analysis by the Virginia Department of Environmental Quality (VDEQ).

At SML, 2023 turned out to be a productive year for cyanobacteria – with over 70 citizen reports of conditions that could have been HAB related and several confirmed HAB areas.  The Blackwater arm of SML was the hardest hit, but the Roanoke arm had several sightings of possible HABs that could not be verified because Weather conditions prevented DEQ from safely collecting samples, before they dissipated.

One thing that was clear last year, none of the samples collected at SML contained toxins above the state advisory levels. Very low levels of cyanotoxins were detected in just a few samples. It is often the case that cyanobacteria can bloom but never produce toxins at levels that are a concern. But not enough research exists to say when and how a bloom starts to produce toxins.

What does a Harmful Algal Bloom (HAB) look like?

A HAB may or may not be visible. You may notice that the water has lost some of its normal clarity; it may look murky, darker green, or even, alarmingly, bright blue. Sometimes streaks of material that look like spilled paint, or soupy scum can be noticed on the water surface. HABs go through a lifecycle, and when they begin to die off, they get clumpy, pea soup-like and can often have an odor of rotting grass clippings.

The blue and/or green heavy, pea soup-like consistency is a defining visual characteristic of HABs. But even when color changes are not present, this doesn’t mean that there isn’t a risk of cyanobacteria overgrowth and potential for toxicity. The cyanobacteria move themselves through the water column to either get sunlight during the day or back to the lakebed in the evening to access nutrients in the sediment. Toxins can be present even if a visible bloom is not, but remember, cyanobacteria are naturally occurring water creatures; it’s only when they overgrow that they become potentially harmful.

What can look like a HAB, but isn’t?

Pollen: Any allergy sufferer will tell you that March until June is particularly hard! All the tree and grass pollen that collects on our cars, outdoor furniture, and walkways also settles on still lake water. Pollen accumulations can sometimes look a bit like a HAB although the color is generally more of a greenish yellow and can feel gritty to the touch. If you touch water coated in pollen, the pollen often sticks to your fingers.

Green Algae: Our lake is home to many microscopic lifeforms, such as diatoms, green algae, and cyanobacteria. These form the base of the food chain which feeds our game fish. Anyone who owns a dock will likely have noticed that brownish clumpy stuff which seems to grow on your swim ladder, on jet ski lifts, and even on the rip rap that is under water. This is a type of green algae which turns brown as suspended sediment settles out. If you happen to touch it, it isn’t super slimy, as opposed to what it looks like – it’s woolier and fibrous. These green algae aren’t the most pleasing to look at, but they’re not a HAB. Other lake organisms such as watermeal, a tiny plant, float and look alarmingly bright green, but they are not HABs.

What happens when a bloom is suspected?

When a citizen, SMLA volunteer, or Ferrum College researcher notices visual conditions that may be suspicious, a report can be filed with the VDH which will trigger a response protocol. This is a link to that report form: https://www.vdh.virginia.gov/waterborne-hazards-control/harmful-algal-bloom-online-report-form/

VDH will send the Virginia Department of Environmental Quality (VDEQ) to collect water quality samples for analysis at a state certified lab which measures the concentration of cyanobacteria in the sample by counting cells and then analyzes the water sample for the presence of toxins. The Commonwealth of Virginia has established two thresholds to determine if a HAB is present: 1) elevated concentration of cells of cyanobacteria and 2) elevated toxicity level. If either of these thresholds is exceeded, the VDH recommends the placement of a Swimming Advisory on the affected portion of the waterbody.

What is a Virginia Department of Health Swimming Advisory?

In 2023, the Blackwater arm of Smith Mountain Lake was placed under a Swimming Advisory by the VDH which began on June 6th and lasted until August 24. VDH determined that a Swimming Advisory for the entire Blackwater arm was warranted because three samples taken by DEQ in early June showed elevated concentrations of cyanobacteria above the advisory level. None of the samples contained toxins anywhere near the advisory threshold, although toxins were present.

A VDH Swimming Advisory does not mean the lake is “closed”. The reason for implementing a Swimming Advisory is to inform the public that a health risk might be present, based on sampling results. At the time a water sample is collected, either concentrations of cyanobacteria and/or toxins are found to exceed the established thresholds.

A Swimming Advisory recommends staying out of water that is discolored, has a visible scum, and/or has an odor. Bathing after contact with the water is highly recommended. Drinking the lake water is never recommended. Non-contact recreation such as boating, kayaking, fishing, and sports that don’t lead to submersion of your head in the water, are recommended as safe alternatives during a Swimming Advisory.

Recreation can continue in the water, but awareness of the risks is important. It is up to you to make the choice to swim, or not, based on the information that VDH provides in the Swimming Advisory. SMLWQA always advocates that if the water looks or smells unusual, when in doubt, stay out.

How does a Swimming Advisory end?

Only the VDH can end a Swimming Advisory based upon resampling, two times, and both samples must show that no thresholds are exceeded. The sampling events must be a minimum of ten days (10) apart.  If the first return sampling event still shows elevated concentrations and/or toxins, the clock starts over, meaning another 10 days must pass before resampling.

This was the case for portions of the Blackwater arm last year. Multiple rounds of resampling occurred before VDH could end the Swimming Advisory for the full arm. By early July, part of the Swimming Advisory in the lower Blackwater was lifted based on two clean sampling results, but the upper Blackwater samples continued to show elevated levels of cyanobacteria into mid-July. Two more sampling events occurred in the Upper Blackwater on July 17th and August 15th. By August 24, 2023, the Swimming Advisory was lifted for the upper Blackwater.

There was much concern last summer that the Swimming Advisory lasted too long and may have covered too broad an area of SML.  SMLWQA anticipates greater coordination and communication with VDH and DEQ this coming season.

What do you do if you see something that might be an HAB?

If you notice conditions in the lake that look anything like following pictures of HABs, and you are pretty sure it’s not pollen or plants, you can file a citizen report with the VDH on their HAB portal. You will need to provide your street address, contact information, and importantly, a photo, latitude, and longitude of where you saw the suspect water conditions. You can get that from Google maps.

Visit: https://www.vdh.virginia.gov/waterborne-hazards-control/harmful-algal-bloom-online-report-form/ to report conditions you suspect may be an HAB.

We also encourage you to notify SMLA, via email lqcchair@smlassociation.org, to report the conditions to us as well.

When the VDH receives a citizen report, they first reach out to Ferrum College and the Smith Mountain Lake Association to see if those groups can get a sample and look at it under a microscope. If citizen photos and Ferrum/SMLA feedback cannot rule out a HAB, VDH will trigger the VDEQ to respond and collect an official sample for analysis of cyanobacteria concentration and toxicity.

If you file a report, you may be contacted to allow VDEQ personnel onto your property to collect a sample at your dock or shoreline location. The sample team may come by boat, and not need property access. The VDH will follow up directly with the citizen posting the report with testing results, although results can take up to two weeks to receive.

What Happened at SML in 2023?

What happened in 2023 to produce widespread and long lasting HABs? Why have we never had a Swimming Advisory before? Will it come back?

These are questions many people are asking and were asking last summer. While we still don’t know exactly why the summer of 2023 was seemingly so different from other summers, we do know the triggers for harmful algal blooms are an overabundance of cyanobacteria, excess nutrients in the water and warm, sunny weather. And these conditions were not localized to just certain sections of the lake. Citizen reports from many areas of the Blackwater arm were filed along with reports from the Roanoke arm.

The lake has had and still has concentrations of nutrients, especially phosphorus, that are relatively high compared to other bodies of water. Although the lake wide average of phosphorus has remained relatively constant for the past number of years, upper reaches of the lake, like up the Blackwater and Roanoke have higher levels than areas down near the dam.

Phosphorus and other nutrients are introduced into the lake through runoff and stormwater. Sources of these nutrients include lawn and agricultural fertilizers, livestock, pet, and wildlife waste, leaking or malfunctioning septic systems, and erosion/siltation. Nutrients can also be found in the lake bottom. Sunken leaves, brush, and dissolved organic material all release nutrients as they decompose. Streams feeding into the lake have been found to contain elevated phosphorus levels as well.

In late May 2023, we had quite a bit of rain followed by quickly warming waters and air temperatures. The perfect mix of nutrients and warm, sunny, and calm days really kicked the cyanobacteria into high gear last year, right before the Memorial Day weekend. We have certainly seen small, short-lasting blooms in the past, but not as widespread and long lasting as the summer of 2023.

What is Being Done?

How do we start to understand this complicated puzzle? The first step is to assess the condition of the watershed surrounding the lake. What percentage of the watershed is forest, farm, houses, and impervious cover? How many septic systems are within 100 feet of the lake edge? What kind of rainfall and runoff comes into the lake? How do streams and other flow characteristics affect the surface water of the lake?

These questions are being asked now by the Smith Mountain Lake Association (SMLA) with a study being prepared by a professional lake management and engineering firm. To enhance this study, SMLA contracted for the sampling of sediment and surface water at the sites of the original HABs last summer, in the Blackwater. The sediment samples are being analyzed to see if cyanobacteria survive the winter and are potentially ready to go as soon as the weather warms up.

A new group of volunteers organized by SMLA is going to be collecting samples at docks this year. Organized through the NOAA Phytoplankton Monitoring Network, the SMLA Dock Watch program will monitor 20 dock locations around the lake. Volunteers have been trained by NOAA scientists to identify the most common cyanobacteria at the lake with microscopes. This program will help establish trends as well as keep an eye out for emerging conditions which could evolve into HABs.

In exciting news, the General Assembly included budget language and funding for a Harmful Algal Bloom study of Smith Mountain Lake in the State budget. This study will be conducted by Virginia Tech in partnership with DEQ and SMLA. The study will determine if HABs are going to recur at SML, what the conditions are that create HABs at SML, propose ways to prevent future HABs and discuss opportunities for future monitoring programs for blooms at the lake.

And last, but not least the Ferrum College SML Water Quality Monitoring Program is in its 38th year, with over 50 volunteers participating from SMLA. Out on the lake weekly between the end of May and early August, these volunteers and researchers are trained to watch for conditions that might be suspicious while conducting their regular sampling.

What will Summer 2024 Bring?

No one knows for sure if conditions will be similar to 2023, and if HABs will return to SML this coming summer. We do know that the winter of 2023-2024 was one of the warmest on record, if not the warmest. We also know that nutrient sources around the lake in the watershed have not changed since last year. But will warm weather, sunny skies and calm late spring days combine again to set us up for a repeat of last year? The best answer is Maybe? For now, as of June, no HAB reports have been filed with the VDH and no elevated levels of cyanobacteria are being observed by Ferrum College or Dock Watch.

The SMLWQA is a group of lake community members made up of business owners, SMLA board members, Ferrum College representatives, County emergency management officials, residents, and state officials, all working together to align messaging, provide timely information and help the SML area understand water quality issues.

Questions? Comments? Please reach us at lqcchair@smlassociation.org, or on Facebook, https://www.facebook.com/smlassociation.org/ or through the SMLA main office number (540) 719-0690.