2025 Water Quality Monitoring Report
Smith Mountain Lake Association (SMLA) announces the publication of the final 2025 report of the Smith Mountain Lake Water Quality Monitoring Program. The key conclusion of the report is that the water quality in Smith Mountain Lake is very good. The full report, linked below, consists of 84 pages of technical data and scientific analyses.
The Water Quality Monitoring Program was established in 1986 as a collaborative effort between SMLA and Ferrum College, with the goal of monitoring the overall health of the lake. The program involves 50 or more citizen volunteers who take water samples and water clarity readings at 84 sites on the lake every two weeks during the summer, and seven faculty members and 3 students from Ferrum College who take additional readings on the lake and process the samples collected by citizen volunteers.
Key take-aways from the report are summarized below.
Three key parameters sampled by citizen volunteers combine to form what is known as the Trophic Status of the lake. These consist of:
1. Chlorophyll-a concentration, which is an indication algae in the water
2. Total Phosphorus, an important nutrient that in large amounts can contribute to excess growth of algae
3. Water clarity, which reflects the density of particles suspended in the water, primarily algae and sediment.
For 2025, the results of these three parameters were very much in line with the respective 20-year averages for each parameter, which is very good news from the standpoint of long-term trends. The year started out with unfavorably elevated levels of phosphorus and algae, and reduced water clarity, mostly related to multiple bouts of heavy rain experienced in 2025 during the month of May. As the summer progressed each of these parameters improved significantly, which brought the full year 2025 averages in line with historical 20-year averages, and only slightly inferior to 2024.
The report also notes that these parameters can vary considerably for different parts of the lake, with the uppermost areas of the lake experiencing less favorable results than the lowermost areas that are closer to the dam. This is because the nutrients and sediment that flow into the lake from the surrounding watershed tend to gradually settle out from the water as it winds its way downstream toward the dam.
Several parameters sampled by Ferrum College faculty and students provide additional information about the health of the lake:
1. Levels of E. coli bacteria throughout the summer were found to be within acceptably low levels defined by the Virginia Department of Health.
2. The mix of phytoplankton species in the lake were found to be dominated by green algae and diatoms, and a relatively low presence of potentially harmful cyanobacteria (blue-green algae). There were no confirmed reports of toxic algae blooms in the lake in 2025.
3. Water temperature profiles continue to demonstrate the thermal stratification of the lake is occurring earlier each year, with adverse implications for the level of oxygen in the lower depth of the lake that forces cold water fish to migrate closer to the uncomfortably warm surface. This phenomenon is largely climate driven.
The Water Quality Monitoring Program is supported by generous funding from Appalachian Electric Power, Bedford Regional Water Authority, Western Virginia Water Authority, a grant from Virginia Department of Environmental Quality, and donations from local businesses and citizens.
