The Dupi Tila aquifer of Dhaka, Bangladesh: Hydraulic and hydrochemical response to intensive exploitation

Dhaka, the capital of Bangladesh, has a population of 8.5 million in an area of 250 km(2). Groundwater provides 95% of the public water supply. 270 Mm(3) per year is pumped from 190 public supply boreholes throughout the city in the confined Dupi Tila sand aquifer. Private abstraction accounts for an additional 40 Mm(3) per year. The city population, and with ir the water demand, is rising at more than 5% per year. Recharge, by vertical leakage through the confining layer and by induced leakage from rivers, is insufficient to satisfy the heavy abstraction. Water levels are declining at 0.75 m per year, the aquifer has become unconfined across most of the city, and there is a trend of deteriorating groundwater quality. Sources of contamination may be the chemical industries and municipal landfills which lie within the large piezometric depression in the urban area, and/or industrial effluents which are discharged untreated into the River Buriganga.