Evaluation of GRACE and GRACE-FO derived-products for water storage assessment in Moroccan aquifers: analysis of drought and human-induced impacts

Groundwater overexploitation in Morocco’s arid and semiarid regions poses a sustainability challenge. The Gravity Recovery and Climate Experiment (GRACE) offers valuable groundwater monitoring potential, despite its coarse resolution. This study evaluates GRACE and GRACE-Follow-On products against groundwater level data. The GRACE-Self-Data Assimilation product showed the best performance in Haouz-Mejjate (PCC = 0.97, RMSE = 0.21) and Bahira (PCC = 0.93, RMSE = 0.29), whereas the Goddard Space Flight Center product was more accurate for the Errachidia-Boudnib Cretaceous basin (PCC = 0.39, RMSE = 0.92) and Jurassic aquifers (PCC = 0.93, RMSE = 0.28). Meanwhile, the Jet Propulsion Laboratory’s Mass-concentration solution performed best in Fezna-Tafilalet (PCC = 0.83, RMSE = 0.76). The results show that the combined datasets (Mass-concentration solutions mean and the Combination Service for Time-variable Gravity Fields product) offer the best overall performance. Alarming declines in water storage occurred in Haouz-Mejjate (−0.37 ± 0.018 cm/month) and Bahira (−0.36 ± 0.021 cm/month) during 2015–2022, while southeastern aquifers remained stable until 2018, before declining. The findings emphasize GRACE’s utility in groundwater management.