Relação entre a clorofila-A e o Índice de Vegetação por Diferença Normalizada (NDVI) no reservatório de Barra Bonita - SP

Abstract

The Barra Bonita reservoir was implemented for electricity generation, but it is also used for supply and industrial development of municipalities in the state of São Paulo. Factors such as diffuse pollution of agricultural residues, in addition to the lack of basic sanitation in its surroundings, lead to high discharges of domestic and industrial effluents in the reservoir, favoring eutrophication. The objective of this study was to analyze the relationship between Chl-a data and the Normalized Difference Vegetation Index (NDVI) from Landsat 8 satellite Operational Land Imager (OLI) sensor images in the Barra Bonita - SP reservoir. Chl-a data and water temperature of the Barra Bonita reservoir, both provided by the São Paulo State Environmental Company CETESB, on the dates closest to the Landsat 8 satelite passage were used to relate the NDVI spectral index and Tropical Rainfall precipitation data. Measuring Mission (TRMM) respectively. This study obtained excellent Remote Sensing results for the Barra Bonita reservoir monitoring, as the data analysis found that the high temperatures and lower rainfall of 2014 and early 2015 were the main contributing factor to the bloons of chlorophyll and phytoplankton organisms in January 2015. The NDVI proved to be a very useful tool for Chl-a analysis presenting good relationship between these variables, correlation R (0.89) and coefficient of determination R² (0.80). The Barra Bonita reservoir Chl-a can be derived from NDVI spectral index, viewed from satellite images.