Study on the coordination of flow and sediment transport, ecological environment, and crop production in the Lower Yellow River since 2000

Abstract The Xiaolangdi Reservoir has been operated for 23 consecutive years, greatly altering the flow and sediment processes of the Lower Yellow River. Many research have separately analyzed the changes of siltation in reservoirs and river channels, discharge capacity of the lower river channel, river regime stability, or ecological environmental benefits under water and sediment regulation. However, the multiple changes of flow and sediment transport, ecological environment, and social economy were seldom considered. We systematically and holistically explored the changes of river system in the Lower Yellow River since 2000, based on the channel erosion and siltation, channel morphology, ecosystem patterns and habitat quality, irrigation water scale, and crop production index. The results show that the discharge capacity of the main channel has been recovered significantly at a bankfull discharge of over 4700 m3/s. The ecological pattern in the Lower Yellow River and the delta has been optimized. The wetland and water ecosystem area has been remarkably increased by 125.82% and 318.54% respectively, and the saline‐alkali land area has been sharply reduced by 89.65%. The habitat quality has been raised to the highest level in nearly 40 years. The irrigation water volume in the irrigation area of the Lower Yellow River has been increased by 31%, and the grain production has maintained a continuous growth for 16 years. Overall, the coordinated development level of flow and sediment transport, ecological environment and crop production in the Lower Yellow River has been continuously improved from the reluctantly coordinated level (before water and sediment regulation) to the highly coordinated level.