The river sediment volume and intensity

cross section and the thalweg change of Sanhe Dam-Chaozhou Water Supply Project section of the Hanjiang River were analyzed using the measured topographic data from 2002 to 2017. Based on the sediment transport balance

combined with the amount of river channel sand mining

the main controlling factors that cause the channel erosion and deposition are determined. The results are as follows: 1） The thalweg of the Hanjiang River Sanhe Dam-Chaozhou Water Supply Project section shows a downcutting trend. During the period from 2002 to 2017

the average downcutting values of the Sanhe Dam-Gaobei hydro-junction

Gaobei hydro-junction-Dongshan hydro-junction and Dongshan hydro-junction-Chaozhou Water Supply Project were 1.92 m

1.15 m and 5.38 m

respectively. 2） Sanhe Dam-Dongshan hydro-junction had a slight deposition from 2002 to 2008 and an erosion trend from 2008 to 2017. The erosion intensity decreased in Sanhe Dam-Dongshan hydro-junction

but increased in the Gaobei-Dongshan hydro-junction. 3）During the period from 2002 to 2017

the river channel of Dongshan hydro-junction-Chaozhou Water Supply Project showed an erosion trend

and the erosion intensity decreased first and then increased. 4）Based on the theory of sediment balance in the river and in combination with the sand mining quantity

it is believed that the sand mining is the main controlling factor that causes the river bed down cutting.