Acta Geographica Sinica ›› 2021, Vol. 76 ›› Issue (1): 101-113.doi: 10.11821/dlxb202101008

• Water Cycle and Related Land Surface Processes • Previous Articles     Next Articles

Evolution characteristics and driving factors of the water level at the same discharge in the Jingjiang reach of Yangtze River

CHAI Yuanfang1,2(), DENG Jinyun1, YANG Yunping2,3(), SUN Zhaohua1, LI Yitian1, ZHU Lingling2,4   

  1. 1. State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China
    2. Changjiang River Scientific Research Institute of Changjiang Water Resources Commission, Wuhan 430010, China
    3. Key Laboratory of Engineering Sediment, Tianjin Research Institutes for Water Transport Engineering, Ministry of Transport, Tianjin 300456, China
    4. Bureau of Hydrology, Changjiang Water Resources Commission, Wuhan 430010, China
  • Received:2019-07-29 Revised:2020-12-05 Online:2021-01-25 Published:2021-03-25
  • Contact: YANG Yunping;
  • Supported by:
    National Key R&D Program of China(2018YFB1600400);CRSRI Open Research Program(CKWV2018463/KY);CRSRI Open Research Program(CKWV2019727/KY);CRSRI Open Research Program(CKWV2017502/KY);National Natural Science Foundation of China(51979132)


Water and sediment transport processes have been changed by the operation of larger scale reservoirs, which can result in the adjustments of river topography and water levels. The polynomial fitting method was applied to analyze the variation characteristics of the water levels under different characteristic water discharges in the Jingjiang reach of the Yangtze River during 1991-2016. The segregation variable method was used to estimate the contributions of the varied riverbed evaluation, the downstream controlled water level and the comprehensive roughness on the altered water level at the same flow. The results obtained are as follows: (1)The low water level in the Jingjiang reach of the Yangtze River during 1991-2016 presented a significant downward trend, and this trend intensified since 2009; riverbed scouring was the dominant factor for the reduced low water level, while the increased roughness alleviated this reduction. (2) During 1991-2016, the high water level decreased firstly and then increased. The variation characteristic of "high flood discharge with high water level" before 2003 transformed into "average flood discharge with high water level" since 2009. The increased comprehensive roughness was the main reason for the increased high water level, while the river scouring alleviated this increase. For navigation conditions and flood control, the intensifying riverbed scouring of the sandy reaches downstream dams enhanced the effects of the downstream water level on the upstream water level. (3) This led to the insufficient water depth in the reaches below dams, which should arouse great attention. The variation characteristics of high water level increased the flood pressure in the middle reaches of the Yangtze River.

Key words: water level at the same flow, spatio-temporal evolution, channel geomorphology, middle reaches of the Yangtze River