Conjunctive Use of Surface Water and Groundwater Resources under Deficit Irrigation

In this study, a genetic algorithm optimization model is applied to two different scenarios of deficit irrigation in an attempt to develop an appropriate plan for the conjunctive use of surface and ground water resources in Nekouabad irrigation zone located in Zayandehrud Basin, Iran. The study aims to reduce water consumption, define an optimal cropping pattern, decrease the annual decline in the local water table, and to maximize the farmers’ net financial returns. Scenario I is based on normal conditions in terms of both water resources and weather parameters in the region while Scenario II is implemented to develop a 5-year irrigation plan for the study area. For the 5-year period in Scenario II, all possible weather (i.e., dry, normal, and wet) conditions are considered. Results show that water consumption would reduce by almost 24 million cubic meters and the net financial return would decline by 22% under Scenario I. Scenario II reveals that the decline in net revenues would be less under normal and wet conditions than it would be under drought conditions.