The aim of this study is to improve the groundwater management through technical and institutional approaches in order to maintain the water resource sustainability in the study area of Chtouka Ait Baha located in the Souss Massa region in Morocco. This agricultural area of primary importance supplies most of the national exports of early vegetables and currently exploits two irrigation water resources: groundwater and surface water; a third one is expected to be available after the implementation of a desalination project aimed at lowering the pressure on the conventional water resources. A mathematical nonlinear optimization model was used to identify the optimal water demand from the different sources, the associated cropping pattern and the impacts on the economic performance of the agricultural sector.
[...]
Different scenarios of water availability and water tariffs were simulated and, finally, a technical tool to implement the optimal solution and control groundwater pumping was proposed. When maximizing an objective function and setting resources availability constraints, the optimal solution is mainly determined by the crop net margin, the climate and market risk, the irrigation water requirements, and the fixed land constraint for permanent crops. Results showed that the area allocated to irrigated crops and the profit increase after the implementation of the desalination project. Obtained results also proved that the irrigation water demand is quite rigid, and the water price policy is not effective; therefore, fixing a quota for each farmer can be the best way to manage irrigation water. In order to implement the quotas policy, a metering tool called “Water Card” was proposed, allowing the farmers to use irrigation water whenever they need by respecting the quotas fixed by the operator who is able to collect all the data about the farmers’ operations and consumption. The quotas for groundwater can change every year depending on the water table situation, while, thanks to the optimization model, threshold values can be set for the demand of surface and desalinated water that makes the economic performance of farmers compatible with the sustainable use of water resources.
