Mathematical programming models for optimising irrigation water management in Egypt
A major challenge facing Egypt is the ever increasing demand for water against the fixed water supplies. Therefore, a greater emphasis is currently being placed on the need to improve the efficiency in the use of the available water resources for crop production. The study presents a practical approach to manage and optimise the irrigation water use given water, land and organisational constraints. A linear programming (LP) mathematical model was developed to make decisions about irrigation water management options in conjunction with optimal cropping patterns to ensure optimal use of water. The results showed that there is potential to increase net income from crop production through efficient allocation of irrigation water under the prevailing irrigation situation. The results also showed the impacts of different water policies on the area allocated for each crop, resource use and farm income using comparative-static planning models. Three scenarios were evaluated. Under increased water supply scenario, the total gross margins for all crops increased. However under the drought scenario, the total margins decreased. Finally under water charging (partial cost recovery) scenario, farm income decreased reflecting the increased production costs. There was no impact on resources use under water charging scenario. This may provide valuable guidelines for pre-season indicative planning for cropping patterns and irrigation water use in the Egyptian agriculture.