Latest Water Quality Tests Show SML Is Safe for Recreation
Smith Mountain Lake, VA – The results of the fifth round of sampling by the Smith Mountain Lake Association (SMLA) Water Quality Monitoring program continues to show that the lake remains clean and safe for recreation. These favorable results are in line with historical 20-year averages.
SMLA volunteers have been monitoring the lake water quality for 40 years. Water samples and water clarity readings are taken at 84 sites on the lake.
Water clarity reflects the volume of particles suspended in the water, primarily algae and sediment. The average water clarity across all sites sampled in the lake for the week ending July 18 measured 1.82 meters, a slight decrease compared to the previous week’s reading of 1.90 meters.
Water clarity usually declines somewhat during the summer due to cumulative algae growth. Water clarity has been adversely impacted this year by sediment being washed from the increased exposure of unprotected shoreline due to lower than normal lake levels.
Chlorophyll-a is a measure of the volume of algae growing in the lake and is expressed in terms of parts per billion, or ppb. The average concentration of chlorophyll-a across all sites sampled for the week ending July 18 was 8.50 ppb, a significant improvement compared to the previous week’s result of 9.82 ppb. The level is still higher than the corresponding 20-year average of 7.26 ppb.
Phosphorus is a key nutrient for all living organisms. Too much phosphorus in the water can contribute to undesirable growth of algae. The average concentration of phosphorus across all sites sampled for the week ending July 18 was 22.99 ppb, in line with the previous week’s result of 20.29 ppb. This is slightly better than the 20-year average of 25.41 ppb.
These results are an average of all the sites monitored on the lake. Results from specific locations around the lake may vary significantly from the lake-wide averages. Detailed results are posted at the SMLA website at www.smlassociation.org.
In addition to the samples collected by volunteers, scientists from Ferrum College collect bi-weekly water samples at 14 locations on the lake and test them for the presence of bacteria. In the week ending July 18, all samples were well within the Virginia Department of Environment Quality guideline for bacteria in recreational waters.
About SMLA
The Smith Mountain Lake Association (SMLA) mission is to keep Smith Mountain Lake clean and safe. Established in 1969, SMLA is the longest serving advocate for the SML community. Activities help to retain the pristine beauty of Smith Mountain Lake and the vibrant local economy. SMLA is a nonprofit 501(c)(3), volunteer-led organization that relies on memberships, donations and grants to support programs that protect SML.
Mike Garcia collects a water sample to be analyzed for concentration of chlorophyll-a and phosphorus.
