Estudo do comportamento de aquíferos aluviais no período seco no semiárido do Nordeste brasileiro.

Abstract

This dissertation was developed in an alluvial aquifer located in the homogeneous micro region of Catolé do Rocha - Pb where hydrogeological studies identified the aquifer with approximately 3.0 km in length, width ranging from 50 to 250m and thickness of the alluvial pack from 8 to 12m. Three pumping tests were performed in the aquifer system, and an average hydraulic conductivity of 4.27 * 10-3 m / s and an effective average porosity of 11.72% were calculated, being characterized as a typical aquifer in the micro region. According to the aforementioned characteristics, a mathematical model of uni-dimensional flow was applied, not permanent under isotropic and heterogeneous conditions, which uses the techniques of finite differences and the basic implicit method of Jacob and Gauss - Seidel, with iterative resolution to solve the partial differential equation of the underground flow to the particular aquifer. The verification calibration process for groundwater levels, presented satisfactory results in the simulation process, for the period corresponding to the season drought (June to December 1936). At this stage, the model presented valuable contributions, which were the calibrated values ​​of the hydrodynamic parameters of the aquifer, such as hydraulic conductivities and effective porosities, contribution flows referring to the south, northwest and east springs, the calculated flows and the storage in each node of the network. The versatility of the mode, through the applications of maximum demand flow exploitation of each property rural and underground dams with demand flow exploitation provided important results of groundwater levels, natural flow and the volume stored along the modeled stretch, which allowed to systematize the use and the capacity of rational exploration of the aquifer, providing important parameters for small projects for the use and planning of the region's underground water resources.