With a surface area of 306 Km2, the Réghaya watershed is located in the High Atlas of Marrakech and is considered one of the most important sub-basins of Oued Tensift, one of Morocco's major water reservoirs. Unfortunately, this area is highly fragile and vulnerable to natural conditions and human impacts. The present study, entitled "Low-water levels in the Oued Réghaya watershed: determination, extraction and analysis", falls within the context of extreme events and phenomena, in particular the hydrology of low-water levels, which is part of the water scarcity problem. The hydrological regime of the Oued Réghaya is characterized by the succession of two periods: a high-water period starting in February and lasting until June, and a low-water period starting in July and lasting until September.To characterize the severity of low-water periods statistically in our study area, we used series of hydrometric data based on low-water indicators defined by the pair (flow, duration), such as the QMNA and the VCNd, to obtain the characteristic low-water flow value.