Análise geomorfométrica como subsídio a identificação de áreas prioritárias de proteção e recuperação de mananciais para abastecimento público

Abstract

This paper was developed with the objective of proposing a method of analysis using geomorphometric parameters of a drainage basin in which is possible to establish one more subsidy to the identification of areas suitable for carrying out projects whose main purpose is the maintenance, conservation and recovery of river spring areas. Using ModelBuilder tool, present in the Arcgis 10.3.1 software, it was possible to link useful landscape information using a Hydrologically Consistent Digital Elevation Model. The methodology used to calculate priority areas for the protection of springs considering geomorphometric factors was the combination of Multicriteria analysis and Map algebra. Based on these techniques the following parameters were calculated: Geomorphologic potential indicator for soil moisture retention, extracted from the combination of aspect and curvature of the relief, the Slope and slope orientation, which was combined to verify the natural regeneration capacity of the vegetation and also the Topographic Factor (TF), present in the Universal Soil Loss Equation (USLE), which represents the susceptibility of landscape to loss of soil, finally these indexes were combined with the attribution of weights, thus generating priority areas. Two scenarios were developed in order to explore the parameters used, in Scenario 1 the Topographic Factor of Soil Loss (TF) entered the equation as a positive factor, aiming in this way to prioritize areas with high soil loss, although it decreases chance of management success, due to costs, it would lower local erosion processes and increase water quality of the nearest water body, the results obtained were: Low priority 47.5%; Medium priority 44.3% and High priority 8.2% in the extension of the drainage basin. In Scenario 2, the equation is replaced, and the factor (TF) becomes negative, in this case the objective is to prioritize areas whose soil loss occurs less frequently and thus increase the chances of regeneration and consequently decrease the costs of the magement project. The result on the total area of the Rio das Flores watershed was: Low priority 5.2%, Medium 76.3% and High 18.4%. Finally, the application of this result was observed in 8 properties participating in the project “Conexão Mata Atlântica”, demonstrating the practical feasibility of using the proposed analysis method.