Quantifying the changing pattern of water level conditions and groundwater potential zones in a rapidly urbanizing Kamrup metropolitan district of Assam, India

The identification and management of groundwater resources are critical for sustainable development since there is an increase in demand for groundwater use. Geospatial remote sensing approaches are vital to groundwater resource evaluation and conservation. We studied the spatiotemporal dynamics of land use change between 2000 and 2020 and its impact on water level conditions and groundwater potential zones in a rapidly urbanizing Kamrup metropolitan district of Assam, India. The thematic maps, such as land use and land cover (LULC) in 2000 and 2020, geology, geomorphology, topsoil sand, topsoil clay, and slope, were used to define groundwater potential zones. The analytical hierarchy process was used to quantify the weight, rank, and reclassification of various thematic maps. The assigned weights of LULC, geology, geomorphology, topsoil sand, topsoil clay, and slope were 70%, 14%, 4.6%, 4.6%, 4.6%, and 2.2%, respectively. The groundwater potential zone classified as "good" has decreased in cumulative area by 19% during the study period. The increase in the "very good" groundwater potential zone is primarily associated with conservation of lakes and other surface water bodies. Urbanization is the primary driver for decreased groundwater potentiality in the study region. Shallow (<2 m below ground level, bgl) groundwater levels are associated with "good" groundwater potential zones, whereas intermediate (2-5 m bgl) groundwater levels are associated with "moderate" groundwater potential zones. Groundwater levels in built-up areas are showing falling trends, except in a few places where the water levels are rising, which suggests a lack of monsoonal recharge due to increased imperviousness. Without sustainable planning, the change in groundwater potential zones and a falling trend in the depth to water levels could threaten the lives of people in this region.