Geophysical Investigation of Major Structural Controls on Groundwater Distribution, North of Sao Raimundo Nonato, Piaui State

Finding a good supply of uncontaminated groundwater appears to be the only solution for the shortage of surface water observed in semi arid Piaui state, northeast Brazil. The rainfall is low and concentrated from November to March. Its annual rate varies from about 1000 mm to 500 mm in the state when moving eastward from the Amazonian tropical forest, being insufficient to sustain adequately the domestic and agricultural needs of the region. Dry rivers channels are a common feature during the dry season and droughts are episodical.