Water Quality and Chlorophyll Measurement Through Vegetation Indices Generated from Orbital and Suborbital Images

The study was developed at the Municipality of Sao Gabriel do Oeste, State of Mato Grosso do Sul, Brazil, where were performed analyses of water samples, including physical and chemical aspects, obtained through Hanna multi-parameter probe into four different parts of the study area. Landsat satellite 8 (L8) and unmanned aerial vehicle (UAV) was also used to generate vegetation indices, using the visible spectral range for both types of images and normalized difference vegetation index (NDVI) just for L8. Later, these ratios were correlated to chlorophyll a that has a key role in photosynthesis. Regarding the physical and chemical parameters, the collection point 2 was the most differed to the others; this may have happened to be a dam with little flow in an eutrophication process. Through the water absorbance curve in the visible wavelengths, it is possible to estimate comparatively water body that has larger amounts of dissolved materials in the water. There was a high correlation between vegetation indices generated from aerial photographs and L8 image, with chlorophyll a extracted from water in the laboratory. In this sense, they are likely to use to forecast future scenarios. It is suggested the use of aerial photographs of UAVs for monitoring the environmental quality of small water bodies, considering its high spatial and temporal resolution.