Derivative analysis of pumping tests carried out in fractured aquifers in the Jundiaí Municipality - state of São Paulo, Brazil

Abstract

Groundwater extracted from crystalline aquifers is the main water supply in many parts of the world, particularly in developing regions such as Sub-Saharan Africa, Brazil and India. Decades of research have revealed the strong complexity of the flow regime in these aquifers, which are notably heterogeneous and anisotropic. It has been long assumed in Brazil that water is stored in vertical geological discontinuities associated with ancient fault zones. Given the high potential of pumping tests to identify flow regimes, this paper presents a derivative analysis of pumping tests performed in three wells located in the Jundiaí municipality - State of São Paulo, Brazil, aiming to improve the understanding of conceptual flow modeling of fractured aquifers. Adjustment attempts applying solutions for simple vertical and horizontal fractures did not produce satisfactory results. Although no tested solution produced perfect adjustments to the drawdown curves obtained in the pumping tests, the best adjustments were observed when the solution for fractured aquifer with double porosity was applied, which is compatible with the geological context of study area. Further studies, similar to those described in this paper, should be conducted to improve the understanding of flow conditioners for this type of aquifer.