The aquifer mapping and nomenclature guidelines for the Bengal Basin, Bangladesh

Groundwater investigation in the Bengal Basin requires standardized characterization and naming of hydrostratigraphic units to ensure consistency in research, interpretation, and management. The existing aquifer nomenclature in Bangladesh remains inconsistent, with names derived variably from lithologic, stratigraphic, geographic, or depth-based classifications. Consequently, the same aquifer is often referred to by multiple names across studies and agencies, creating ambiguity and limiting comparability of hydrogeological data. This study establishes a standardized, physiography-based aquifer mapping and nomenclature framework for the Bengal Basin. Approximately 5,000 borehole lithologic logs were compiled from national hydrogeological archives, of which 3,506 were standardized and analyzed through stratigraphic correlation, three-dimensional modeling, and interpolated maps using RockWorks 16 and ArcGIS. The study identifies Seventeen physiographic units with distinct hydrostratigraphic characteristics and introduces a uniform three-part coding system integrating district abbreviations, physiographic identifiers, and aquifer depth sequences (e.g., BG-BT-Aqf1 for Bogura Barind Tract Aquifer 1). Results show that transmissivity and permeability are highest in the floodplain and deltaic regions, while uplands and hilly areas exhibit lower hydraulic properties due to finer sediments and limited recharge. The proposed framework provides a consistent scientific basis for aquifer delineation, mapping, and data integration. It enhances groundwater resource assessment, supports arsenic and salinity management, and strengthens coordination among agencies for sustainable groundwater governance in Bangladesh.