Groundwater resources in the hard to reach areas of Bangladesh: Constraints for drinking water supply and strategies for sustainable use

An assessment is made on the current groundwater use and further development potential in the hard to reach (HtR) areas of Bangladesh following a combination of secondary literature review and synthesis of primary information gathered from the fields. Also, primary analyses of groundwater quality, levels, recharge and use were done using secondary data. The findings reveal that the hydrogeology of the HtR areas is generally complex and highly variable except for the char areas of the Jamuna River. Groundwater mining is evident in both the high barind and hilly areas. There are also groundwater quality problems in both these areas. In contrast, recharge is not a constraint and there is no firm evidence of groundwater mining in the HtR areas of coasts, haors and chars. However, groundwater quality, particularly arsenic and salinity, appears to be a major concern. In addition, lateral intrusion of saline surface water due to sea level rise, and vertical infiltration from storm surge flooding pose a great risk to existing freshwater sources in the coasts and offshore islands. A number of drinking water supply options are currently in practice. The use and sustenance of the options are context specific and linked to technical, economic and social aspects. Multiple options are expected to continue at least in the near future in most of the HtR areas. However, tapping targeted aquifer, piped water supply and desalination plant are among the emerging options. Institutional coherence is needed for monitoring groundwater quality and regulating its use.