The current water quality at Smith Mountain Lake is excellent. According to the Smith Mountain Lake Association(SMLA), that water quality so far this year is better than the recorded 20-year averages.

These results are from the Smith Mountain Lake Association (SMLA) Water Quality Monitoring Program, which recently completed the fourth of six bi-weekly monitoring sessions. The latest weekly sample data as well as 20-year averages are posted on the SMLA website.

• Average water clarity at the 84 sites sampled was 2.35 meters, substantially better than the 20-year average of 2.08 meters.
• Average Chlorophyll-a concentration at the 56 sites sampled was 6.65 parts per billion, compared to the 20-year average of 7.30 ppb. Chlorophyll-a is an indicator of algae growth in the lake, so a lower number is more favorable.
• Average phosphorus concentration at the 56 sites sampled was 26.66 parts per billion, compared to the 20-year average of 27.52. Phosphorus is a polluting nutrient that can stimulate unwanted algae growth, so a lower number is more favorable.

“These findings for the lake as a whole provide a good indicator of the overall health of the lake,” according to SMLA Director of Water Quality Monitoring, Tom Hardy. “However, individual sections of the lake can vary considerably from the overall averages as the graphs posted on the SMLA website show.”

The highest water quality is typically found in areas farthest downstream such as those closest to the dam, and lower water quality is found in the uppermost sections of the lake. This reflects how nutrients and sediment flow into the lake from streams and the surrounding watershed which eventually settle out of the water as it flows downstream toward the dam.

The SMLA Water Quality Monitoring Program is a partnership between SMLA and Ferrum College. The monitoring program has operated continuously since being established in 1987. Roughly 50 citizen volunteers collect samples on the lake every two weeks in the summer. The samples are analyzed by a team of student interns and environmental science professors at Ferrum College.