Modelagem de fluxo subterrâneo com vistas à depleção do rio como efeito do bombeamento extremo em uma área de estudo situada no oeste baiano.

Abstract

This present work presents numerical simulations of stream-aquifer depletion models for groundwater rights administration and decisions. To achieve these objectives numerical modeling techniques are used to analyze streamflow depletion which are generated by a pumping well located at a given distance from the river. The first part of the study uses a simple hypothetical stream-aquifer model under varying .geometrical and hydrogeological parameters of the stream-aquifer system and calculates the induced stream infiltration and reduced baseflow rates, respectively, which both contribute to total streamflow depletion. The simulation results suggest that the induced infiltration has a shorter term impact on streamflow while the reduced baseflow shows a longer term effect. The residual effects in the postpumping period which can last very long are also studied in this model. Based on the knowledges of the hypothetical model the second part of the study calculates the both depletion flow components for a real sandstone aquifer (Urucuia aquifer located in the western part of Bahia state) with its hydraulically connected streams. Known the hydraulic parameters determined from well and aquifer tests done by the water agency of Bahia state in 2003, the selected study area (Fazenda Campo Aberto) is simulated for different hydraulic gradients under varying well pumping scheme and long term pumping periods. The present work helps in understanding the hydrologic interactions between stream and aquifer for areas where groundwater quantity and quality are a concern and provides useful information to the development of water resource management plan.