Orbital imaging of the Furnas reservoir: spatial-temporal variability of the water level and hydrometrics inferences

Abstract

There are several variables that guide the generation of energy in hydroelectric power plants, two of which are the useful volume and the altimetric quota, and its monitoring is performed mostly by linimetric rulers. The objective of this study is to obtain the spatial-temporal frequency of the water level of the Furnas reservoir, in the period between 1995 and 2019, as well as to adjust regression equations between the parameters water surface area, altimetric height, and useful volume. Thus, images from Landsat 5 and 8 satellites were used to map the water surface and daily data about the altimetric height and the useful volume. The equations between the parameters were adjusted adopting a coefficient of determination bigger than or equal to 0.70 and a 95% confidence interval. The mapping of the spatial-temporal frequency of the water level showed regions of significant oscillation of the water level, near the mouths of the rivers Grande, Verde and Sapucaí, besides the proximities of Campo do Meio and Alfenas. Results show that the statistical adjustment was satisfactory in the estimation of the parameters with R² of 0.9805 and 0.9913, for the relations between area versus useful volume and area versus altitude, respectively. The aim of the results is to provide subsidies for actions that guarantee the multiple use of water resources.