Assessment of the potentiometric drawdown in the Guarani Aquifer System in Bauru/SP by a model of analytical elements

Avaliação do rebaixamento potenciométrico no Sistema Aquífero Guarani em Bauru/SP usando um modelo de elementos analíticos

ABSTRACT

The recent drought events and the population growth in São Paulo State (Brazil) have caused many municipalities to increase the groundwater exploitation of the Guarani Aquifer System (GAS) for the public water supply. In Bauru City/SP, the extraction of water from this Aquifer is expected to increase from 3699 m³/h (2014) to 4465 m³/h (2034). However, its long-term overexploitation may compromise the amount of available groundwater. The Analytic Element Method was used for groundwater flow modeling at steady-state, which includes the regional flow, the water withdrawal from wells and the main local geological conditions. The hydraulic gradient 0.82 m/km was estimated in the GAS in Bauru City. The potentiometric drawdown in the GAS in Bauru was estimated as 50 m since the beginning of the groundwater exploitation. The drawdown for the groundwater pumping scenario in 2014 is higher than 15 m in Piratininga and Agudos and lower than 10 m in further cities. The expected drawdown for the scenario of 2034 can reach 15 m in comparison with the scenario of 2014, in the North of Bauru City, where the future wells will be located.

Keywords:
Hydrogeology and groundwater; Analytic element method; Water resources management; Guarani Aquifer System