Water accounting and analysis of water-saving potential for reservoirs and irrigation areas under data scarcity

Abstract

[Objective] Water resource management in the Yangtze River Basin faces many challenges, especially low agricultural water use efficiency and incomplete data measurement. These problems not only affect the rational allocation of water resources but also restrict the effective management of droughts in the river basin. To address these problems, an accounting method for the total water leakage and discharge in irrigation areas under the condition of data scarcity is developed. [Methods] An irrigation area in the middle and lower reaches of the Yangtze River was taken as an example. Multi-source remote sensing data and an improved SCS-CN model considering irrigation-induced surface runoff were utilized. Key factors such as rainfall, evaporation, irrigation water volume, surface runoff, and water supply from waterworks were integrated to estimate water consumption and water loss from the reservoir to the irrigation area, and the gap between potential and actual evapotranspiration was calculated. [Results] The result showed that the proportion of deep leakage and water discharge loss in the water supply of the irrigation area reservoir was significant, and the ratio of unmeasured water volume to the reservoir outflow water volume reached as high as 1.11. High water-saving potential could be realized in the future through measures such as precise irrigation regulation and canal seepage control renovation. [Conclusion] The results show that through the calculation and analysis of the monthly water supply and demand of the reservoir, it is found that during the summer irrigation period from June to October, the reservoir outflow matches well with the irrigation water demand, and the loss ratio is relatively lower, which verifies the feasibility of the method. Based on reliable data sources and rigorous methodological logic, this method can provide an effective reference for reservoir water management in irrigation areas with data scarcity. It offers a scientific basis for prioritizing daily water supply during dry seasons, optimizing reservoir outflow scheduling to reduce losses, and improving water resource utilization efficiency, thereby alleviating drought and water scarcity issues.

Keywords

data scarcity / improved SCS-CN model / multi-source remote sensing data / water accounting in irrigation areas / water-saving potential / reservoir / Yangtze River basin / influencing factors