Groundwater occurrence and productive potencial of the aquifer systems in the metropolitan region of Campinas - SP

Abstract

The present work is a hydrogeologic assessment of the Campinas Metropolitan Region, central-eastem portion of the state of São Paulo. The study area belongs to the urbanized region of the Piracicaba and Capivari watersheds, where occur two regional aquifer systems, the crystalline and the Tubarão aquifers; locally, diabases also occur. 1711 wells were registered, of which 1008 hydrodynamic data were available (e.g. static and dynamic levels and yield); 1217 have geological logs, and 10 pumping test results.The results showed the strong influence of tectonic structures, normal faults and fracture density on the productivity of wells in the crystalline rocks. Productivity may be also related to the neotectonic movements. ln the weathering materials an aquifer of primary porosity develops. Specific capacity showed a median value of 0.1 m³/h/m and yield of 5.2 m³/h. The transmissivities of six wells were 0.32, 0.13,0.14,0.18,6.85,0.29 and 1.18 m²/day. The underground sandy sediments and the high values of sediment thickness were parameters related to better production of wells in the Tubarão Aquifer System. The median value ofspecific capacity and yield are 0.11 m³/h/m and 6.0 m³/h, respectively. Wells in diabases presented low values of specific capacity (0.06 m³/h/m); their productivity is related to fractures. The productivity of wells that exploit more than one aquifer system may be related to the saturated thickness of the sedimentary aquifer and to the deeper limits between aquifer units. Production zones may be related to structural blocks with neotectonic movements, encountered in the study area. The median value of specific capacity and yield are 0.07 m³/h/m and 4.8 m³/h, respectively. Wells that exploited both the diabases and the Tubarão Aquifer System showed the highest values of productivity. Transmissivities were determined in three wells, obtaining the values of 0.113, 2.77 and 0.71 m²/day