Groundwater vulnerability and urban activity assessment: the Narayanganj Bangladesh case-study. BGS Technical Report WC/00/21.
A pragmatic groundwater risk assessment for groundwater protection and urban development planning purposes is described for the city of Narayanganj, Bangladesh. The city is highly groundwater-dependent for potable, domestic, commercial and industrial water supplies which are
provided by both intraurban and periurban boreholes. The groundwater setting is hydrogeologically complex, with an uneven silty clay aquitard covering an upper aquifer of highly variable thickness that is separated from a deep productive aquifer by a second aquiclude. The risk assessment needed
to take account primarily of the shallow aquifer, which is widely and increasingly used for rural and small-scale periurban community supplies. Using simple GIS techniques and working with available data, a map showing areas of low, moderate and high vulnerability together with a plan of potentially hazardous activities was produced collaboratively by the British Geological Survey and University of Dhaka Department of Geology team. This is incidentally the first attempt to apply groundwater vulnerability mapping in Bangladesh. The interaction between the two themes has provided a groundwater resource-planning map which is the key plan required for the second stage of this project, in which urban groundwater protection policies are evolved and guidelines developed for more general use.