Mapeamento do potencial de águas subterrâneas no Estado do Ceará

Abstract

The assessment of the potential of tubular well water is essential, especially in regions with a scarcity of surface water resources, where the use of this resource is crucial. The research focuses on evaluating the potential of tubular wells in the State of Ceará. With a specific approach, the objectives include mapping the flow rate and electrical conductivity variables of these wells. The study aims to assess the performance of the Kriging and Inverse Distance Weighting (IDW) interpolators for the flow rate and electrical conductivity variables. To achieve this, flow rate data from 8,024 wells and electrical conductivity data from 12,580 wells across the territory of Ceará were used. Geostatistical tests were conducted using QGIS software. From the flow rate and electrical conductivity maps, salinity risk maps for agricultural use and maps of the minimum irrigable area capacity for Ceará were created, using a specific flow rate coefficient, as well as maps of dynamic, static, and drawdown levels of the water table. Based on the semivariogram results, both interpolation methods, Kriging and IDW, demonstrated consistency in the results; however, the chosen method, due to a lower RMSE, was ordinary Kriging. The most suitable semivariogram model for flow rate was the potential model, while for electrical conductivity (EC), it was the exponential model. Additionally, the mapping of EC and flow rate produced results consistent with the characteristics of the state as presented in the study area maps. The average flow rate value for the State of Ceará was 5.45 m³ h⁻¹, while for EC, the average value for the Ceará territory was 2.21 dS m⁻¹. The results obtained with ordinary Kriging in the mapping of salinity risk and minimum irrigable area capacity were also consistent with the specific characteristics of the studied aquifers.