Mapeamento de lineamentos estruturais e sua influência na potencialidade hídrica do Sistema Aquífero Serra Geral na bacia do Ribeirão Cambé em Londrina, PR

Abstract

The demand for natural resources, mainly water, to attend the most diverse human activities is increasing and to supply this demand the utilization of groundwater is notable. This is already a reality in the municipality of Londrina-PR, which is located on the Serra Geral Aquifer System (SASG), a fractured type aquifer in which the water circulation and storage is conditioned to the physical discontinuities of the rock (joints, faults and fractures). The fractures, present as rectilinear features in the relief and when mappable in the terrestrial surface, are called structural lineaments. The objective of this work was to identify and map the main structural lineaments of the SASG and its influence on the hydrological potential of tubular wells in the Ribeirão Cambé basin in Londrina-PR by using geoprocessing and remote sensing tools. For the identification and mapping of the structural lineaments, a georeferenced GIS database was created, in which radar (SRTM) and Landsat 8-OLI satellite images were used and processed. The shaded relief technique was applied to the SRTM image, using four different types of lighting angles: 45 °, 135 °, 225 ° and 315 ° for the purpose of reinforce the main features of the terrain. In the satellite image, the multispectral bands (30m spatial resolution) were merged with the panchromatic band (15m) and the RGB color composition was performed using bands 1, 2 and 3, respectively. For the data analysis, rosette frequency diagrams of the structural lineaments were elaborated as well as the descriptive statistics applied to the wells data, using the outflow, specific capacity, depth, static level and dynamic level. For the analysis of the correlation between the tubular wells and the structural lineaments, the buffer tool was applied to the lineaments, using classes of 200 meters and using the Multivariate Analysis of Variance (MANOVA) and Canonical Discriminant Analysis (CDA). From the obtained results, 22 structural lineaments were identified through the SRTM images and 14 lineaments through the Landsat 8-OLI images. The images that allowed a better identification of lineaments was the SRTM images, in which the predominant direction of the fractures was NW. MANOVA confirmed that the variables of analyzed wells had differences between the groups of buffers defined a priori defined, whereas the ADC showed that the flow variable is the most influenced by the distance between the well and the line, followed by the specific capacity. Also with regard to productivity, it was observed that this is also influenced by the depth of the wells. Finally, it was possible to demonstrate the importance of hydrogeological studies for the management of water resources and for the economy, helping to reduce environmental impacts, as well as reducing financial expenditures for drilling very deep wells or even drilling wells.