Climatic and hydrological variability in the Oued Lakhdar watershed (Central High Atlas, Morocco)

Abstract The results of this study highlighted significant changes in hydroclimatic conditions over the period studied. Annual rainfall shows significant variability, with years such as 1996 characterised by exceptional humidity, while others, such as 2017, stand out for their particularly marked drought. This variation can be quantified using the Rainfall Anomaly Index (RAI), providing crucial information for water resource management. Temperatures also show seasonal fluctuations, oscillating between hot summers and cold winters. In particular, 2017 was exceptionally warm, while 2011 was unusually cold. In terms of river flows, there has been considerable variability, with some years showing high flows (e.g. 2011) and others with very low flows (e.g. 1990). However, the general trend towards an increase in flow from the 2010 onwards is notable (Sgat station). The RCV index, which classifies years according to surplus or deficit, highlights the predominance of deficit years. In addition, the Monthly Flow Coefficient (MFC) allows us to subdivide the hydrological regime into periods of high and low water. These results highlight the importance of monitoring hydro-climatic conditions for effective management of water resources and the implementation of measures to adapt to climate change.