UAVs vs Satellites: Comparison of tools for water quality monitoring

Cyanobacterial Harmful Algal Blooms (CyanoHABs) thrive in calm, shadow and warm On-Farm Reservoirs (OFRs) where the water is rich in nitrogen, phosphates, carbonates and organic matter. In addition, water toxicity can vary from hour-to-hour and day-to-day and it can remain toxic even after a bloom has disappeared. Thus, OFRs should be monitored frequently for outbreaks and establish assessment programs. Satellite-based remote sensing is a broadly used method for water quality assessment and CyanoHABs monitoring because of its specialized sensors and availability of historical data of the water body. However, the spatial and time resolution may not be enough in case of outbreaks in OFRs. On the other hand, Unmanned Aerial Vehicles (UAV) emerge as a cost-effective alternative with high spatial and temporal resolution. In this paper, a comparison between satellite and UAV remote sensing approaches for monitoring CyanoHABs in a small and shallow water reservoir is conducted. UAVs rise as a reliable complement to satellites thanks to their superior temporal and spatial resolution.