Acta Geographica Sinica ›› 2016, Vol. 71 ›› Issue (9): 1509-1519.

• Orginal Article •

### Variation of channel lateral erosion/accretion and channel shrinkage rate in the Linhe Reach of the Yellow River since 1977

Yanguo MEI1,2(), Suiji WANG1()

1. 1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China
2. University of Chinese Academy of Sciences, Beijing 100049, China
• Received:2016-01-06 Revised:2016-05-25 Online:2016-11-25 Published:2016-11-25
• Supported by:
National Natural Science Foundationof China, No41271027, No.41271027;Special Program of the Study of National Basic Research Program (973 Program), No.2011CB403305

Abstract:

Taking the Linhe reach of the Yellow River with a channel length of 213 km as an example, this paper evaluated the area changes of channel bank erosion/accretion in four sub-reaches (S1, S2, S3 and S4) during 19 different periods on the basis of remote sensing images since 1977. Furthermore, the mean channel shrinkage rate for the whole river reach was obtained. The results show that the left and right banks of the Linhe reach were dominant in lateral net accretion during the period 1977-2014. For the left bank of the four sub-reaches, the accumulative lateral accretion areas during 1977-2014 were 33.16 km2, 49.59 km2, 29.52 km2 and 30.85 km2, respectively, while the lateral accretion areas during 1995-2000 accounted for 85.5%, 51.2%, 47.2% and 104.6% of the accumulative values, respectively. For the right bank of the four sub-reaches, the accumulative lateral accretion areas in 1977-2014 were 30.83 km2, 8.74 km2, 26.44 km2 and 18.76 km2, respectively, while the lateral accretion areas during the period 1995-2000 accounted for 57.2%, 111.9%, 65.7% and 61.6% of the accumulative values, respectively. The channel area of the Linhe reach was characterized by a reduction tendency from 1977 to 2001, and alternate erosion and accretion after 2001. The channel mean shrinkage rate of the Linhe reach was 6.16 km2/yr during the period 1977-2014. The most remarkable change of channel planform of the Linhe reach also occurred in the 1990s. Compared with 1995, the channel length and sinuosity increased by 5.8% and 6.6% and the channel area and mean width decreased by 39.4% and 42.8% in 2000, respectively. Significant channel planform changes and channel shrinkage for the Linhe reach occurred in the 1990s, which was mainly influenced by the joint-operation of the Longyangxia and Liujiaxia reservoirs since 1986, which resulted in substantial reductions of runoff and sediment fluxes in flooding season in a year. In addition, the bankerosion-accretion for the the four sub-reaches was also affected by the physical properties of local bank, protection engineering of channel bank and hydrodynamic differences. With the implementation of integrated river management measures since 2000, these changes have been significantly weakened and the river's health has been restored.