USING AN UNMANNED AERIAL VEHICLE EQUIPPED WITH A MULTISPECTRAL SENSOR TO VISUALLY MAP WATER QUALITY PARAMETERS IN DRINKING WATER RESERVOIRS.

Surface drinking water infrastructure is an integral part of the development and sustainability of societies around the world. However, these surface freshwater resources have been a challenge to monitor due to the vast number of in-situ samples needed to accurately quantify constituents, expenses of equipment, coordination of personnel, and lab cost. Lake Bloomington and Evergreen Lake (Hudson, Illinois) are two vital surface water features that serve as the drinking water reservoirs for the Bloomington area. Both reservoirs are within agricultural watersheds, with watershed inputs typically being high in turbidity and nitrate. We utilized an Unmanned Aerial Vehicle (UAV) coupled with a five band multispectral image sensor to monitor two important drinking water parameters in the lakes; turbidity and algae. By using the UAV, along with in-situ data collected the same day as the flight, we aim to answer the following questions: 1.) What are the challenges of remotes sensing over a homogeneous setting (such as a lake) and 2.) Is it possible to detect change in the water quality at the surface of the lake using one or more spectral image combinations? Preliminary results show that at nearly 6 cm pixel size can produce greater than 80% coverage at each sample site and regularly above 90% coverage at 3 m resolution. Through several proprietary algorithms, we were able to explain 70% of the variation of Chl-a in the lakes. Although algorithms were created for Turbidity and TSL, both algorithms were only able to explain less than 20% percent of the variation of the observed samples. This poor correlation has to do in part with the low values and concentrations observed for both Turbidity and TSL respectively