Uso do Sensoriamento Remoto para avaliar o potencial hidrogeológico do município de Crateús-CE

Abstract

In the municipality of Crateús, the reduced availability of surface water combined with the low and irregular rainfall, characteristics of the northeastern semi-arid regions, explains the great dependence on groundwater in the region, even though this is, to a large extent, a fragile option, as a result of the low potential hydrogeological structure presented by the predominant crystalline rocks in the municipality. Therefore, it is necessary to search for alternatives that help in the recognition of areas with potential for exploitation of this resource. That said, the objective of the work was to identify areas conducive to the occurrence of groundwater through the application of remote sensing and field analysis. To this end, a georeferenced database was created, using IBGE files, relating to the geology and hydrography of the municipality of Crateús; CPRM data, referring to the wells registered in SIAGAS; SRTM and MDE images from the USGS and ASF digital repositories. The data obtained were processed in a GIS environment using the QGIS software to prepare thematic maps. The well location maps allowed us to select two areas with the greatest potential for carrying out more detailed studies in the districts of Poti (Well A) and Tucuns (Well B), in the communities of Feijão and Santa Luzia, respectively. The interpolation maps of the specific flow of the wells, elaborated from the IDW interpolation tool, made it possible to identify, within the selected areas, areas with greater probability of occurrence of groundwater. Finally, the sub-basin delimitation maps made it possible to analyze the flow segments in the areas, as well as the possible aquifer recharge zones. Fieldwork included carrying out exploratory activities to better understand the selected areas. Data were collected regarding the water table of the wells, as well as the identification of rocks and geological structures in the vicinity of wells A and B. occurrence of groundwater, which gives these areas a greater probability of successful drilling of new wells.