Socio-hydrogeological Potential for Managed Aquifer Recharge in the Fresh-saline Aquifers of Southwestern Bangladesh

In coastal areas, groundwater resources are under pressure. To ensure the sustainable provision of safe drinking water under these increasing pressures, groundwater resource management is essential. An important technology to increase the sustainably available groundwater is Managed Aquifer Recharge (MAR). In southwestern Bangladesh, drinking water provision is problematic, leading to the consumption of bacterial-polluted pond water or the consumption of arsenic or brackish groundwater. To overcome these drinking water problems, MAR has been piloted in the form of 99 small-scale, community-run systems.

A large part of the thesis focusses on understanding the large variation in groundwater salinity in this data-poor region. This variation is first researched at a local scale, to develop a conceptual model of steering palaeo and present-day hydrological processes and geomorphological controls. Subsequently, this conceptual model is used to understand the relation between landscape features, hydrological processes and groundwater salinity at a regional scale. Next, the research focusses on assessing the attachment of users to their current, often unsafe water options via interviews. The last part of the study builds on the previous results to map the regional potential for MAR based on both social necessity and technical suitability.

This study is the first to demonstrate the relation between landscape features, hydrological processes and groundwater salinity throughout southwestern Bangladesh. Additionally, the study utilizes and provides an innovative method to assess and map the socio-hydrogeological potential for MAR, which shows whether implementation should focus on either improving the acceptance of MAR or on overcoming anticipated technical challenges, or on both. The findings and methodology of the study can be used for predicting the occurrence of valuable fresh groundwater and the socio-hydrogeological potential of MAR in coastal areas worldwide.