An integrated geomorphological and hydrogeological MMS modeling framework for a semi-arid mountain basin in the High Atlas, southern Morocco

The aims of this study are to develop and implement a precipitation-runoff model in the Modular Modeling System (MMS) for a small mountain catchment, the Ameskar basin. It is part of the meso-scale, semi-arid Drâa basin investigated within IMPETUS, an integrated project for the efficient and sustainable use of freshwater in southern Morocco. The River Drâa drains from the High Atlas Mountains to Lac Iriki and feeds a large dam for irrigation purposes. Precipitation inputs include rain and snow from 3 climate stations. Snow sublimation plays a significant role in the higher altitudes and is integrated accordingly. Vegetation is scarce outwith the intensively irrigated oases and evapotranspiration is limited to small shrubs. Surface runoff and springs are controlled by complex geomorphological and geological settings and by highly porous, infiltrating wadi river beds. The MMS model has been developed mainly on the basis of geomorphologically and hydrogeologically defined Hydrological Response Units (HRUs). Discharge is sporadic, extreme and varies according to snowmelt and precipitation. Infiltration dominates over surface discharge and is important for groundwater renewal especially in limestone and basalt. MMS will be developed for the whole Drâa catchment for operational discharge forecasting in future.