Comparison of the area of water masses in a hydrographic basin using spectral indices and MapBioma’s classification

Abstract

Information surveys about water resources availability present in a basin is essential for its multiple use planning. In this context, the purpose of this study was to evaluate the reservoirs area in a semi-arid hydrographic basin, comparing information obtained from spectral indices with data from the MapBiomas classification. The study was carried out in the contribution basin of the Chapéu reservoir, in the Brígida River Basin, Pernambuco State. To assess the area of water masses in the basin, data from the classification carried out by the MapBiomas project -collection 5, referring to the year 2019, were used. The NDWI and MNDWI indices were also applied to images from the Sentinel-2 Satellite, referring to the year 2019, to determine the areas of reservoirs in the basin. The information from the indexes was vectored to obtain the polygons of each reservoir and calculate their respective areas. The use of the NDWI and MNDWI spectral indices for the identification of water bodies provided similar areas for the Chapéu reservoir, the main reservoir in the study basin, approaching the volume values obtained with the local monitoring of the reservoir. The assessment of water masses in the basin based on spectral indices and the MapBiomas classification provided information on the masses with high spatial resolution, enabling the identification of bodies in the basin, and it could be used as a tool for monitoring water resources.

Morphometric characterization of the Alto do Ipojuca hydrographic basin

“…O estudo das bacias hidrográficas considera a organização dos corpos hídricos no espaço e sua evolução morfogenética ao longo do tempo, bem como a influência da geologia da região a qual pertence. Principalmente quando se trata de regiões como o semiárido, onde se verifica elevadas restrições hídricas devido à irregularidade de chuvas, altas variações de temperatura e altas taxas de evapotranspiração, a análise morfométrica de bacias tem subsidiado uma série de decisões importantes no que se refere a gestão dos recursos hídricos (Cherem et al, 2018;Lourenço et al, 2021;Oliveira e Silva, 2020).…”