Aplicação do índice da vegetação por diferença normalizada (NDVI), na análise multitemporal da área da Usina Hidrelétrica de Itaipu, Foz do Iguaçu – PR

Abstract

The hydroelectric plants provide energy for the whole society to be used for the most different purposes, whether in industry, commerce, or housing. The implementation of hydroelectric plants requires a lot of space for allocation and flooding of many areas to form the lake that will be dammed, and also requires a lot of study, planning, mitigation measures, and mapping of sites, because many areas that have tree cover will be affected and within these areas there will be large-scale impacts on fauna, flora, soil, and the environment as a whole. This work aims to evaluate the impacts of the creation of the power plant on the tree coverage in its surroundings that have been modified by the flooding of the Itaipu Power Plant in the region in the municipality of Foz do Iguaçu-PR, through the NDVI index of Remote Sensing. This index is used for mapping areas using satellite images that have the red and near infrared bands in their sensors. The satellites used to obtain the images were: Landsat 5 sensor TM, to obtain images referring to the years 1985 and 2008, and Landsat 8 sensor OLI, to obtain images referring to the year 2021. The NDVI index was applied on a temporal scale to generate maps in the SIRGAS 2000 reference system with geographic coordinates, so that it was possible to analyze and study the areas affected by the flooding caused by the power plant and the behavior of the vegetation at the site, as well as whether the tree cover was affected by the growth and expansion of the municipality. For the year 1985 a maximum NDVI index of 0.0466 was obtained, and the other indices are also below what is adequate according to the literature. For the year 2008 it was obtained a maximum index of 0.4433 and a minimum index of 0.0071 which indicated an index below the adequate and a reduction of vegetation cover in the whole area. In the year 2021 a maximum NDVI of 0.4206 and a minimum index of -0.0069 were obtained, the values generated in the year 2021 are the lowest compared to the years 2008 and 2021. It was concluded from the work that there was a change in the landscape, the chosen years were representative for the generation of NDVI indices, the indices did not remain the same in the chosen years.