Delineation of Fresh Groundwater Potentiality Zones in Saline Coastal Aquifers, Southwest Bangladesh using Remote Sensing and GIS Approaches

Abstract

The southwestern coastal zone in Bangladesh faces freshwater scarcity as aquifers are more vulnerable to seawater intrusion resulting increase its salinity level. But here fresh groundwater resource badly needed for drinking, agricultural, and industrial uses to sustain livelihood. The present study has made attempt to demarked available fresh groundwater zones in Khulna district in the southwestern coastal zone using multi-criteria decision making (MCDM) tool and analytical hierarchy process (AHP) with remote sensing (RS) and GIS approach. To delineate fresh groundwater potential zones, twelve thematic parameters such as groundwater salinity, groundwater electrical conductivity, groundwater chloride, rainfall, concentration of soil salinity, land slope, geomorphology, surface geology, land use and land cover, drainage density, lineament density, topographic wetness index have processed utilizing ArcGIS overlay analytic tool. Accordingly, the area has classified as very good [18 km2 (0.52%)] - safe for drinking and agriculture; good [858 km2 (25%)] - useful only for agriculture purposes; low [354 km2 (11%) - use for irrigation of certain high salinity tolerate crops having high risk for human consumption; and very low [2148 km2 (64%)] - unsuitable to use due to seawater intrusion or high salinity of the total area. The salinity-prone zone covers 75% of the total area requires especial management approach. Finally, findings will aid in identification of fresh groundwater potential zone for human consumption and agriculture in salinity effected coastal zone of the country to ensure sustainable groundwater use and extraction in this coastal areas, and findings of the present study can be utilized as a guide for addressing groundwater issues for this region.