Effects of rainfall intensity and drought patterns on groundwater storage variability in the guir aquifer, Morocco

¹ Environmental Management and Civil Engineering Team, Applied Sciences Laboratory, National School of Applied Sciences, Abdelmalek Essaadi University, Al Hoceima, 32002, Morocco.
² Geosciences, Water and Environment Laboratory, Faculty of Sciences, Mohammed V University of Rabat, Rabat, Morocco.
³ Applied Geosciences Laboratory, Faculty of Sciences, University Mohammed Premier, Oujda 60000, Morocco.

Abstract

Groundwater resources in the Guir Basin of Morocco are increasingly affected by climatic variability, particularly irregular precipitation and prolonged drought events. This study explores the relationship between these hydroclimatic factors and groundwater storage changes by integrating GRACE satellite observations with the Innovative Trend Analysis (ITA) technique. Compared with conventional statistical approaches, the ITA method provides improved capability for identifying temporal variations in groundwater behavior. The obtained results reveal a pronounced decline in groundwater reserves throughout the aquifer system. Approximately 40% of the investigated sites experienced noticeable reductions, while nearly 60% exhibited stronger negative tendencies, with annual depletion rates reaching up to −0.244 cm. These changes are mainly associated with intensive groundwater withdrawal and unsustainable irrigation practices, which contribute to rising salinity levels and degradation of surrounding ecosystems. Although satellite observations cannot fully capture local geological heterogeneity, they remain an effective source of large-scale hydrological information for monitoring aquifer conditions and supporting water-resource planning. The findings of this study highlight the importance of adopting sustainable groundwater management strategies to improve water security in vulnerable semi-arid environments such as the Guir Basin.