Spatiotemporal assessment of sustainable groundwater management using process-based and remote sensing indices: A novel approach

This study aims to develop a process-based method for evaluating groundwater sustainability and use the results in an archetypal analysis to fundamentally frame and understand sustainable development interactions in a river basin scale and sub-basin resolution. This method was applied in the Tashk-Bakhtegan-Maharloo (TBM) basin of Iran between 2003 and 2018; anthropogenic and natural factors were considered. With its 31 aquifers in 27 sub-basins, the TBM basin has repeatedly suffered severe droughts and water shortages over the past half a century, highlighting the importance of sustainable groundwater management. This study quantified anthropogenic and natural factors affecting groundwater dynamics to address sustainability and defined representative and relative indices, including climatological and drought conditions, vegetation cover, land cover, and population, to assess groundwater sustainability (GWS). Relative indices, prepared using measured data and remote sensing analysis, were chosen to explain groundwater-related situations, whereas representative indices, such as groundwater level and total dissolved solids, were used to explain the groundwater situation. GWS was spatially monitored using a couple-indicator trend-line slope comparison method to analyze process-based indices. Then, archetypal interaction patterns and their drivers in the groundwater system were investigated using results from process-based indices analyses results. The results showed that the TBM basin has moved towards unsustainable levels because of drought, increased irrigated croplands, unbalanced development of the sub-basins up- and downstream in the river's path, and over-exploitation of groundwater. These findings indicate that a deeper understanding of groundwater problems and stakeholder associations is required in order to adapt to the changing groundwater conditions.