Smith Mountain Lake 2020 water quality monitoring results

The summer of 2020 has come and gone, and it is time again to report on the health of our lake. First I’d like to say how very proud I am of all of the SMLA water quality monitors and of the Ferrum College staff, who, despite everything going on this year, conducted the water quality program as “business as usual.” I also want to thank those who help fund this program every year, including AEP, the Bedford and Southwest Virginia Water companies, the Virginia Department of Environmental Quality, and of course, our SMLA members. 

Here are the results of our 2020 Water Quality testing this year.

Bacterial Testing: Only one testing period had locations where the E. coli levels exceeded the VDH standards for recreational waters. This occurred during the testing week of June 16th, and this week was preceded by heavy rainfall. The locations with higher readings were in the area near Bay Roc Marina and in the cove near Crystal Shores Marina. It should be noted that the reading near Crystal Shores Marina was only slightly higher than the VDH standard. All of the other five sampling weeks had results that were well below the VDH standard. This is very good news.

Algae: Green algae was the predominate type of algae in the lake this year making up 73 percent, followed by Diatoms at only 14 percent and Blue Green at only 13 percent. The vast majority of the Blue-Green algae found in the lake are of the type that is NOT LIKELY TO PRODUCE TOXINS. Thankfully, blue-green algae counts weren’t higher this year even though we had some algae blooms early in the season. In 2019 Diatoms where the predominate algae making up 56 percent, followed by Green at 32 percent and Blue-Green at 12 percent. Algae effects water clarity.

Secchi Depth / Water Clarity: As I know you have all observed, water clarity this year was not good. As a matter of fact, the water clarity in 2020 is the worst that has been seen in at least 20 years. When Green Algae percentages go up, water clarity does down. 

Phosphorous and Chlorophyll-a: While Phosphorous levels were down from last year and the slope of the average shows it is going down slightly, they were still above the 5-, 10- and 20-year averages. We should all continue to make efforts to reduce the amount of Phosphorous entering the lake since it is a major contributor to algae growth, which is a major contributor to water clarity.

Per Dr. Bob Pohlad of Ferrum College, “I believe the Chlorophyll-a results are related to the higher numbers of green algae we saw this year. The numbers were highest early in the season with the flooding we experienced. That said, I think that the flush of so much organic material into the coves and the lake bottom have continued to add to the nutrient releases and the high green algae numbers again this year.”

To help mitigate the flow of nutrients into the lake, the SMLA has been promoting a Buffer Landscaping initiative, which provides lake residents with free consultation by Master Gardeners and Master Naturalist volunteers who will visit your lake property and assess how best to plant native varieties to absorb these pollutants. 

Also contributing to decline in water clarity in 2020 was increased watercraft traffic all week long, not just on the weekends. Studies on water quality and clarity find that in heavily trafficked waterways, boats have a noticeable impact. The presence of vessels seems to increase the growth of algae and kick up sediments, both of which obstruct sunlight and spoil the water. More boat traffic, and the increased number of watercraft that produce larger wakes, stir up more sediment, especially in the coves, narrower fingers of the lake and shallower upstream areas.

New for 2020: The Smith Mountain Lake Association and Ferrum College have launched a new algae reporting tool. The link to the tool is posted on the SMLA website. By timely reporting of algae blooms via this tool, we will be able to analyze the instances and do source tracking to hopefully cut down on the nutrients being released into the lake causing these blooms.

We believe the implementation of a “Smart Lake” concept would benefit SML and we continue to drive toward that goal. Although SMLA’s application for a grant from the Virginia Environmental Endowment to implement a Smart Lake concept using year-round remote sensors was not approved for 2020, we will be resubmitting an updated version for 2021. The manufacturer of the remote sensors, In-Situ, has loaned us a probe that is currently installed and being tested. We anticipate that our experience gained from the deployment of this probe will strengthen our case for the grant application in 2021.

In Summary, SML continues to have very low E. coli and very low Blue Green algae, making our lake one of the cleanest lakes east of the Mississippi. You can help keep our lake clean and clear by reducing what you put in the lake and by reporting, via the Algae Reporting Tool, any algae blooms you see. 

This wonderful place called Smith Mountain Lake is a little piece of paradise. You can help keep it that way. Help SMLA protect the water of SML.

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