Pequenas barragens de água: definição do grau de hierarquização para fins de fiscalização.

Abstract

Accurate data on the distribution and characteristics of small dams are important for the purposes of emergency management and planning of water resources in the river basin and for monitoring indicators of the Sustainable Development Goals (SDG) 6, on the use and availability of water resources and implementation of integrated water resources management at all levels. It is necessary, therefore, a simplified system that helps in the process of identification and classification of these small dams. In this context, the purpose of this study is to identify the presence of small reservoirs through images from MSI / Sentinel-2 between January and December 2020 and to elaborate a Degree of Hierarchization (DH) for inspection actions by the management bodies. The Normalized Water Difference Index (NDWI), Modified Normalized Water Difference index and the space transformation colors method from RGB to HSV were used for identification. QGIS software version 3.10 and Google Earth Engine were used for image processing and composition of base maps. The results proved that the HSV method presented better result in the identification of the proposed targets. From the application of the DH to a small water dam, it was possible to assess the level of potential risk of the dam and propose a priority scale for inspection actions. Finally, it can be gained that the DH can assist in decision making, providing public agencies with a tool to use to assess the priority of action on small buses.