GIS and remote sensing based weighted linear combination (WLC) of thematic layers for groundwater potentiality study at Plio-Pleistocene elevated tract in Bangladesh

Abstract Water is pondered as strategic resource; that has great ascendancy on human life and socio-economic development. Present study was toted for understanding of groundwater potential (GP) zone at the drought prone Plio-Pleistocene elevated tract in Bangladesh using geographical information system (GIS) and remote sensing (RS). Ten thematic layers escorted for the study were extracted from different secondary sources; that was co-registered and rectified to UTM 45 projection and world geodetic system (WGS) 1984 datum. Layers assimilated using weighted linear combination (WLC); and GIS based multi-criteria evaluation for the class normalization using Satta's analytical hierarchical process (AHP) that was adopted for weight and ranking the class of thematic layers in pair wise comparison matrix (PWCM). Thematic layers viz. drainage density (DD), slope (SLO), geomorphologic (GM) roughness, soil thickness (ST), groundwater table depth (GWTD) have negative influence, besides lineament density (LD), rainfall (RF), infiltration rate (IR) have positive influence with increasing class range values for GP. Surface lithology (SL) and land use/land cover (LULC) are reliant on porosity and presence of water body for percolation into the aquifer respectively. Map removal sensitivity analysis (MRSA) and single parameter sensitivity analysis (SPSA) was also carried for assessing effect of removing the layer and the effective weight of layer on the GP map respectively. The GP map was classified into five zones i.e. very low (26% area or 511 sq. km); low (56% area or 1075 sq. km); moderate (15% area or 282 sq. km); high (2% area or 38 sq. km); and very high (1% area or 25 sq. km). MRSA showing that groundwater table depth is more sensitive with mean variation index of 8.9%; besides SPSA showing that the effective thematic layer is slope (weight 29.7%).