Satellite-derived GRACE groundwater storage variation in complex aquifer system in India

Satellite-based Gravity Recovery and Climate Experiment (GRACE) provides a quantity of available terrestrial water storage and combining the soil moisture from Global Land Data Assimilation System (GLDAS) offering estimation of groundwater storage changes for a region. We applied satellite-driven GRACE–GLDAS data in Weinganga–Wardha and Mahanadi basin to analyze the variation of groundwater storage variation and emphasising the concernment of complex aquifer system to improve the groundwater monitoring. Groundwater-level trends were analyzed for spatial and temporal variation of various aquifer systems. In situ groundwater-level observation and GRACE and its area application comprise selecting pixel. Six pixels from combine GRACE–GLDAS outputs were selected with various aquifer systems, where each pixel contains 10–50 monitoring wells. Groundwater storage anomaly derived using monthly GRACE Release 05 version of the Global Land Data Assimilation System (GLDAS) product for each pixel from 2002 to 2016. Correlation analysis was performed between GWSA (actual) and GWSA (grace) using linear regression. Correlation results show that the simple aquifer was good agreement during premonsoon and during postmonsoon; although the performance was poorer with complex aquifers system. It was found that groundwater storage has been decreasing for many years. This study highlights the significance of integrating GRACE sensitivity in the assessment of groundwater storage change in various aquifer systems.