Evaluation of Aquifer Hydraulic Properties of the Barind Area, Bangladesh: an approach for Groundwater Development

An approach for the aquifer evaluation using hydraulic properties (both geologically based method and method based on hydraulics) has been undertaken in the Barind area, Bangladesh to assess its groundwater development potentiality.

The values of aquifer transmissivity (T) derived from the well-section lithologies are generally less those determined by pumping test analysis. The hydraulic characteristics (T) derived by the latter have to be preferred to those obtained from the former, because of the variability in the aquifer materials of the study area. This refer to the tendency to flush out finest gravity suspended particles from the aquifer sediments through well discharges, not just for a few days from commencing of  pumping but continuing for years and thus increasing permeability of surrounding materials due to new flow-path by re-arranging the sediment grains. Thus the transmissivity value obtained from virgin lithology no longer remains representative of the changed, coarser lithology as time elapses.

An information of pumping test analysis gives only the values of the capillary drainage component of the specific yield, its gravity drainage component is evaluated in the present study from the analysis of the lithological constituents of the lithologs.

Development potentiality of the study area as determined from transmissivity (T) values through pumping test data analysis indicates that the smaller area in the central part is only suitable area for the development of water supply and hand pump use but the majority portion has good development potential for irrigation and water supply.

Author(s):
Chowdhary Sarwar Jahan and Musfique Ahmed
Department of Geology and Mining, University of Rajshahi, Bangladesh.