Avaliação do nível de água do reservatório de Furnas nos anos de 2013 e 2014, utilizando imagens Landsat-8.

Located in the middle of the Rio Grande in Minas Gerais state, Furnas hydroelectric occupies an area of 1440 km², with an estimated volume of 17,217 km³ used to generate 1216 megawatts of power. Around the lake, other economic activities such as agriculture, pisciculture and tourism are also important. A shortage of rainfall in the region in 2014 heavily impacted these activities, causing also a decrease in the reservoir?s power generation capacity. The aim of this study was to assess the reduction of the volume of water in the reservoir using remote sensing and GIS. Landsat 8 26/04/2013 and 19/08/2014 satellite images were compared. The images were processed by eCognition Developer and Arcgis 10.2. It was observed that, in the 2013 image, the reservoir area was at 1134 km2 of water and 71.51% of its capacity. In the 2014 image, the area decreased to 807,42km2 and 27.55% capacity. This difference showed a reduction of 7,082km³ in volume in 16 months. These results show the applicability of satellite imagery and GIS to estimate reservoir areas over time, assisting various sectors in decision making processes and helping to mitigate the consequences of droughts