Optimization model for water allocation for agricultural activities in alluvial aquifer in the Brazilian semi-arid region

The semi-arid region is marked by uncertainties and variability in the water volume available for multiple uses. The objective of the studywas to construct a linear programming model that promotes maximization of the net income of the producer and optimization of the use of water resources in alluvial aquifer in the Brazilian semi-arid region, with a view to economic and water sustainability, establishing an optimal plan for agricultural exploitation. The proposed model used technical coefficients from primary data obtained in the various production units, as well as secondary data from technical-scientific studies conducted in the region, and considered constraints. Simulations were performed for three levels of water availability and two annual cycles of shrimp farming, considering the volume exploited per cycle and the continuous expansion of the activity in the region. The model proved to be efficient in the proposal of an optimal plan of occupation and optimization of groundwater resources, which, in its potential condition, has a relevant importance in the shrimp farming activity from the economic dimension perspective. Sensitivity analysis of the model parameters allowed understanding the stability of the optimal solution in the face of variations in the technical coefficients. The water resource had slack equal to zero, indicating that it is a limiting resource. Drastic reduction in net income due to reduction in water availability points to risks associated with years of water scarcity. Reduction of one cycle in shrimp farming in years of moderate water scarcity is a feasible alternative from a financial perspective.