Monitoring Freshwater Algal Blooms in a Small Lake using Drone Technology

Freshwater cyanobacterial harmful algal blooms (HCBs) pose a significant public health threat to the world’s freshwater supply, including for potable drinking water, recreation, and subsistence-based and sport fishing. The occurrence of toxic blooms in recreational water bodies and potential human exposure to toxins will increase with a warming climate, necessitating novel methods to characterize blooms and communicate risk. Remotely piloted drones with high-resolution cameras can be an effective environmental monitoring tool to track an HCB in smaller scale lakes. This project examined the use of drone-derived aerial imagery to estimate levels of chlorophyll-a--the photosynthetic pigment found in all algae and cyanobacteria--and compared it with chlorophyll-a concentrations analyzed in the lab from lake water samples. Incorporating drones as a supplemental monitoring tool to estimate chlorophyll-a levels in a lake may help freshwater managers better anticipate HCBs and better communicate this human health hazard to the public.