Estudo estabilidade e variabilidade temporal do nível freático e salinidade visando a análise de recarga.

Abstract

The Brazilian Northeast is subject to repeated events of drought and rainfall distribution in time is very irregular, and hence the use water resources is limited. These restrictions are due to rainfall concentrated in a short period of time, with most being lost by runoff and evaporation. The alluvial aquifers, although limited in space, has considerable water reserves understanding of the piezometric levels and salinity behavior in relation to rainfall and its recharge are of great importance for the water resources management in semiarid regions. The present work aims to studying, analyzing and identifying representative areas for level and salinity behavior in an alluvial valley and its variation in time and space, as well as the behavior of recharge through the daily water balance model BALSEQ_MOD to Mimoso Basin which is located in Pesqueira, Brazil. Two piezometers were found stable for the average behavior of the water table and two piezometers to electrical conductivity, and the stable level presented correlation with the behavior of the valley, while electrical conductivity was not stable. In the evaluation of its temporal variability the piezometers with stable level showed ranges of 7-8 months, while the electrical conductivity for piezometers showed a pure nugget effect and the other a range of 2 months. Simulations applying the BALSEQ_MOD showed the strong influence of actual evapotranspiration (ETR) in the behavior of recharge and runoff is highly variable over time for the basin and the alluvial valley.