Contribution to the knowledge of the hydraulic behavior of the fissural aquifer in the semiarid region of Brazil

Abstract

Most fractured aquifers occur in crystalline rocks and are marked by low porosity and low production capacity. The studied area is located in the southeastern portion of the municipality of Passira (PE), this region stood out for presenting wells with flow rates above the expected average for the context of the semiarid region. To raise hypotheses that justify these anomalous flows, field activities were carried out, 62 wells registered and 7 pumping tests lasting up to 60 minutes. Information on NE, Q and CE of the water was collected. It was observed that the main lithotype of the area is the Metanortositic Complex of Passira (CMAP), which is composed of anortositic rocks with intense fracturing. This fracturing, together with the characteristics of the rock itself, are favorable to the storage and percolation of water. However, most of the wells are currently deactivated or with flow rates below the initial ones. It is suggested that this scenario has changed due to the large exploitation of water, coupled with the large number of new wells drilled and the low recharge. Thus, although the rock has good storage conditions, the heterogeneity of the aquifer leads to limitations in its production capacity, and monitoring is essential for better management of the aquifer.