SMLA Dock Watch Program Shares 2025 Results

SMITH MOUNTAIN LAKE, VA – The Smith Mountain Lake Association (SMLA) Dock Watch program successfully completed its second year of monitoring in 2025. The program was initiated following Harmful Algal Blooms (HABs) observed in 2023 and is designed to complement SMLA’s long-standing Water Quality Monitoring and Save Our Streams programs.

Dock Watch is a volunteer-based effort to assess cyanobacteria conditions at docks, where most recreational contact with the lake occurs.

“Thanks to the dedication of our volunteers, we are building a baseline understanding of cyanobacteria distribution and abundance in Smith Mountain Lake. The goal of the program is to increase our understanding of the factors contributing to HABs and, ideally, be able to take action to reduce the probability of future harmful algal blooms,” said Mary Colligan, SMLA Dock Watch program co-chair.

In 2025, Dock Watch included 22 docks, with two new docks added mid-season. Sampling was conducted throughout the year, including a limited winter sampling at selected docks.

A total of 361 samples were collected and analyzed, an increase from 2024 due to both program expansion and extended seasonal coverage. The program is conducted by highly engaged SMLA volunteers supported by two summer interns.

Key findings include:

• Target cyanobacteria were detected in 42.9% of samples in 2025, compared to 30.9% in 2024. Raphidiopsis remained the most commonly detected cyanobacteria and the only one observed at elevated levels. Three samples met the criteria for additional investigation and no HABs were formally designated by state agencies in 2025.
• Phycocyanin levels were generally low across docks and across the sampling season with 84% of the samples having a phycocyanin measurement of less than or equal to 10. Phycocyanin is a screening indicator for the presence of cyanobacteria. The Dock Watch program has set a phycocyanin level of 25 as being worthy of additional investigation.
• Higher phycocyanin levels were more likely to occur with lower water clarity and warmer water temperatures. Water clarity was the strongest single predictor, accounting for approximately 21% of the variation in phycocyanin levels. That highlights the complex nature of cyanobacteria dynamics at docks at Smith Mountain Lake overall.