Acta Geographica Sinica ›› 2019, Vol. 74 ›› Issue (9): 1745-1757.doi: 10.11821/dlxb201909004

• Surface Processes • Previous Articles     Next Articles

Attribution analysis of precipitous decrease of sediment loads in the Hekou-Longmen section of Yellow River since 2000

GAO Haidong1,2,LIU Han2,JIA Lianlian3,PANG Guowei4,WANG Jie1   

  1. 1. State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi'an University of Technology, Xi'an 710048, China
    2. School of Civil engineering and architecture, Xi'an University of Technology, Xi'an 710048, China
    3. Upper and Middle Yellow River Bureau, Yellow River Conservancy Commission of the Ministry of Water Resources, Xi'an 710021, China
    4. College of Urban and Environmental Science, Northwest University, Xi'an 710127, China
  • Received:2018-12-05 Revised:2019-07-28 Online:2019-09-25 Published:2019-09-25
  • Supported by:
    National Natural Science Foundation of China(41877077)

Abstract:

Since 2000, the amount of sediment loads in the Yellow River has decreased sharply. It is of great practical significance to scientifically understand the reasons for the sediment load change in the Yellow River. This study selected the Hekou-Longmen (HL) section, which consists of main sand producing areas of the Yellow River, as the study region, analyzed the sediment discharge change trend, constructed the calculation method of the contribution rate for the sediment reduction of major soil and water conservation measures, such as terraces, check dams, and vegetation, and expounded the reasons of sediment load reduction on the HL section since 2000. The main results were as follows: (1) From 1952 to 2017, there was no significant change of annual precipitation in the HL section, and the annual runoff and annual sediment load both showed an extremely significant (p < 0.001) declining trend. (2) The two mutation years for sediment load reduction in the HL section were in 1979 and 1999, respectively. The average annual sediment loads decreased from 9.30×10 8 t during 1952-1979, to 4.20×10 8 t during 1980-1999, it was, and in 2000-2017, it dropped to 1.03×10 8 t, a decrease of 89%. (3) Influenced by vegetation and terraces, the amount of soil erosion on the slope of the HL section decreased year by year from 2000 to 2015, changing from 1.90×10 8 t to 5.13×10 8 t, and the average annual sediment reduction of check dams from 2000 to 2011 was 1.38×10 8 t. (4) Vegetation restoration was the main reason for the reduction of sediment loads in the HL section, with a contribution rate of 54%. Terraces and check dams, and reservoir and water diversion contributed 34%, and 12%, respectively. (5) Vegetation restoration mainly led to reduced runoff sediments, while check dam construction played a major part in reducing the sediment transport ratio of the basin. According to the changing trend of sediment load, countermeasures are put forward.

Key words: Hekou-Longmen section, sediment load, ecological construction, contribution rate of sediment reduction