Spatiotemporal mapping of groundwater recharge potential zones for physical planning process—A case of Ajmer City, India

Abstract

Urban areas are growing with the growth in urban population and rapidly transforming the land use land cover (LULC), which is capable of affecting the potential of groundwater recharge at a spatial level. It is essential to recognize the complexities of urban growth along with dynamic and static natural parameters that influence the groundwater recharge in the urban region. No substantial inclusion of Groundwater Recharge Potential Zones (GWRPZ) is evident in contemporary master plans of Indian cities, resulting in a declining trend of groundwater tables with increasing dependency. The study discusses temporal changes in the urban LULC of Ajmer City in the State of Rajasthan in India and its impact on the overall Groundwater Recharge Potential Zone over a duration. Nine physical parameters, geology, lithology, geomorphology, lineament density, slope, drainage density, groundwater table, LULC and Rainfall, are used as thematic layers along with their subclasses. The Multi-criteria Decision Analysis of AHP and Weighted Overlay Analysis in GIS are applied to analyze variations at the spatial level on a temporal basis. In addition, Geostatistical techniques such as Empirical Bayesian Kriging (EBK) and Inverse Distance Weightage (IDW) are also applied to interpolate and analyze the thematic layers of the Groundwater table and Rainfall, respectively. The study delineates and analyzes the spatiotemporal variations in the GWRPZs. The confusion matrix method is also applied for validation and accuracy, which is crucial for rationalizing the water-sensitive physical planning process and instrumental in formulating suitable strategies and guidelines for preserving, managing, and retrofitting the groundwater recharge zones at the urban level in the Indian scenario.