Abstract:
Abstract: Precise configuration of multiple water sources in irrigation areas is closely involved with the whole water cycle process of "atmospheric water-surface water-soil water-groundwater". Particularly, changes in hydrological elements can pose a great complexity on the multi-source configuration of irrigation areas. It is very necessary to consider the water cycle process under uncertainty, thereby efficiently allocating the limit water availability to different growth stages of crops in precision irrigation. In this study, a multi-objective model was established to optimize the efficient allocation of multiple water sources under the combined uncertainty of runoff and precipitation in an irrigation area using the water cycle process. Jensen and water scarcity footprint models were also coupled to achieve the synchronization of economic benefits and water saving. An attempt was made to obtain the response characteristics of efficient water distribution to the combined uncertainty of runoff and precipitation. The results showed that the comprehensive water allocation during the main growth period in the irrigation area was 22.41 million m3 under different combined scenarios of surface water supply and precipitation using the water allocation plan and occurrence probability of each scenario. Specifically, the proportion of surface water and groundwater was 6.5∶1, while the water allocation in the field accounted for 95% of the optimal water availability. Furthermore, the goal of economic benefit presented a positive correlation with the field water allocation amount, while the goal of water scarcity footprint presented a negative correlation. The constructed model was also used to weigh the conflict goals of economic benefit, yield and blue water use. In addition, the water productivity increased by 11% in the irrigation area. Nevertheless, the required irrigation at each growth stage greatly varied in the different scenarios. More importantly, the jointing stage was the largest sensitivity to water shortage and the amplitude of water allocation variation. The main water supply source during tillering, jointing, and milk-ripe stages was surface water, while the main water source during heading was groundwater. Correspondingly, the multi-source configuration presented high effectiveness in the irrigation area, where the irrigation reliability fluctuated within the good and medium conditions. Fortunately, irrigation adequacy can widely be expected to serve great potential for improvement in the future. Consequently, the constructed model can be used to clearly represent the impact of dynamic variations in hydrological elements on the allocation of multiple water sources in the irrigation area. A relationship between canal water availability and field water distribution can also greatly contribute to a multi-water source configuration plan with simultaneous improvement of benefits and water efficiency. Particularly, the finding can provide strong decision-making support to the efficient use of agricultural water resources in the irrigation areas.