Groundwater has been used extensively as the main source of drinking and irrigation water supply in Bangladesh and is playing a vital role making the country self sufficient in food production. But, the recent discovery of the arsenic contamination in shallow groundwater has disrupted the potentiality of it's use. Besides arsenic, high concentration of iron, manganese and salinity in many areas and at different depth levels makes water unfit for drinking use. A considered and scientific approach to the development of aquifer can prevent the damage to the aquifer. The objective of this study was to assess the hydraulic and chemical characteristics of the aquifer units in the arsenic affected areas under the Meghna and the Ganges delta floodplains of south-eastern Bangladesh. Groundwater flow models were simulated to determine the potential zones of the heterogeneous aquifer system for long-term safe water supply. The study was conducted with the scientific collaboration of M Qumrul Hassan, University of Dhaka, Bangladesh, K D Balke and C Berthold, University of Tuebingen, Germany, D W Clark, C I Voss and G N Breit, US Geological Survey and H Michael, University of Delawar, USA