Groundwater potential zone demarcation in the Khadir Island of Kachchh, Western India

Abstract

In the present work, remote sensing, Geographic Information System (GIS), field investigation, and mapping methods/techniques were incorporated to demarcate the groundwater potential zones in the Khadir Island of the Kachchh region. Preliminary work consists of reconnaissance surveys and the preparation of various thematic maps of the region. The lithology (Khadir formation of Mesozoic period), slope, soil, land use and land cover (LULC), lineament density (Faults, fractures and linear valleys), drainage density, and geomorphology thematic maps were prepared using Advanced Land Observation Satellite - Phased Array Type L-band Synthetic Aperture Radar (ALOS PALSAR) data with 12.5 m spatial resolution, Sentinel-2 data (bands 8, 4, and 3), and ICAR- National Bureau of Soil Survey and Land Use Planning and Geological Survey of India (GSI) published maps. The Groundwater Potential Index (GWPI) was determined by integrating and computing the groundwater thematic maps. The groundwater potential map was further validated using the Cohen's Kappa statistic method. The GWPI determines a high groundwater potential zone in the study area, of which about 12.24% and 19.41% of the area are excellent and very good potential zones for groundwater extraction, respectively. The study shows that the Cohen's Kappa coefficient of 0.767, which falls under the “Good Strength of Agreement” validates the result and determines that the Western and Eastern parts of the study area have greater groundwater potential zones.