QMNA extraction as a tool for watershed management in a semi-arid climate - the case of the Lakhdar river basin (Morocco)

The process of managing water resources represents a major challenge for all countries in general and Morocco in particular. This study aims determine the water scarcity threshold for the Lakhdar river basin which is a tributary of the Oum Er- Rabia basin, in order to define a reference low-flow level through which regulatory thresholds can be extracted. Water resource managers can rely on it to create effective strategies, especially in this period in which water resources are witnessing a remarkable fragility. We relied on a statistical methodology consisting of analysis of the QMNA (annual minimum monthly discharge) index based on monthly hydrological data for the Sgatt and Admaghene stations during the period between 1986 and 2022. Results show great variability for the Admaghene station, with QMNA values ranging from 23.08m3/s to 0.72 m3/s. This wide range with an average of 4.50m3/s is linked to several climatic and anthropogenic factors. For the Sgatt station, QMNA maximum values recorded 0.24 m3/s in 1996, while some years recorded 0 m3/s (2017, 1990, 1988). This study will contribute to the sound management of the basin's water resources, particularly in times of water shortage, and provides valuable insights for preserving the river's biological diversity, now threatened with extinction.