Water allocation and irrigation scheme considering runoff forecasting of Ulungur River

Abstract

Expanding cropland area in the Ulungur River Basin has led to a significant increase in irrigation demand. Conventional water resource allocation schemes have proven inadequate in guiding annual water resource allocation and agricultural irrigation in arid regions. Additionally, the increasing competition among industrial, domestic, ecological and agricultural water has led to uneven distribution of water resources and river disconnection, which has a negative impact on the stability of the basin ecosystem. This study focuses on the Ulungur River Basin, a typical inland river basin in arid regions, and employs the SWAT model for runoff simulation. A basin-wide water resource allocation model was developed, considering water-saving strategies to formulate water allocation and agricultural rotational irrigation schemes. The results show that: (1) the total inflow in 2023 was 1.0998 × 10⁹ m³, classifying it as a moderately dry year. A water balance analysis revealed a total basin water deficit of 2.917 × 10⁸ m³. (2) After optimizing water resource allocation, the deficit was reduced to 1.679 × 10⁸ m³. (3) An innovative three-tier agricultural irrigation water distribution scheme was proposed, encompassing county-irrigation area-pumping station levels, along with a rotational irrigation plan. This approach reduced the agricultural water shortage rate by 27.2 % while ensuring irrigation area. The findings provide a critical reference for water resource allocation in the Ulungur River Basin, enhancing the operability and practicality of annual agricultural irrigation water distribution schemes.