Water transparency in a brazilian reservoir


Water transparency is regularly monitored in water reservoirs due to its known relationship with phytoplankton biomass and algal blooms. Transparency is also related to other processes in the watershed, such as the input of suspended particles and dissolved organic matter from overland flow. Therefore, the objective of this study was to map water transparency of a Brazilian reservoir (Paraibuna) after a period of intense rain. In regard of that, water transparency was measured in Secchi depth (Zsd). Then, the relationship between Sentinel-2B MSI bands and Zsd measured in situ were assessed, retrieving empirical models and applying them to the imagery. Results showed that remote sensing reflectance (Rrs) increased as Zsd reduced. Zsd was lower in the central area of the reservoir than the periphery areas due to anthropization.