| Summary: | Morocco is already experiencing high levels of water scarcity, and rainfall is predicted to decrease by 20% to 50% under different climate change scenarios. As currently Morocco relies on large reservoirs built to achieve basin-scale water resources management, small-scale reservoirs are investigated here as a possible way to adapt to these dryer conditions and to collect overland flow for irrigation purposes before its evaporation or infiltration into the ground. We investigate a potential shift from basin-scale to farm-scale water resource management. A prototype of such small reservoirs has been built in the experimental farm of Benguerir and this thesis studies its catchment as well as the extent to which this technology could scale up in other regions of Morocco. Runoff production in the form of overland flow is simulated according to the Green-Ampt model while considering the formation of a thin crust of clay typical of dry environments such as southern Morocco. Overland flow is used as input to different models of reservoir management in order to determine the optimal capacity of a potential reservoir in a particular location as function of its catchment area, rainfall pattern, soil type, cost of construction, water price, as well as crops water requirements. Within reasonable assumptions, capacities close to the reservoir in Benguerir (4000 m³) are estimated. However, the results are sensitive to multiple partially unknown parameters such as soil heterogeneity, the intra-day distribution of rainfall and the ratio between construction cost and water price.
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