Ran Dachuan^{1, 4}, Luo Quanhua², and Zhou Zuhao³
1. Yellow River Institute of Hydraulic Research, Zhengzhou, 450003, China
2. Xifeng Soil and Water Conservation Experimental Station, Qingyang, 745000, China
3. China Institute of Water Resources and Hydropower Research, Beijing, 100038, China
4. Xi¡¯an University of Technology, Xi¡¯an, 710048, China

Abstract:In this article, retaining and reducing coarse sediment by the check dams of the five typical catchments: Huangfuchuan Basin, Kuyehe Basin, Wudinghe Basin, Sanchuanhe Basin and Qiushuihe Basin, located in coarse sediment area of Hekou-Longmen Section in the middle reaches of the Yellow River is analyzed profoundly. The amount of coarse sediment retained and reduced by these check dams in different periods are calculated. By analyzing the variation of sediment grain size, check dam area ratio and sediment reduction ratio before and after the check dams and other soil and water conservation measures are put into practices, the author considers that the check dams are the preferred mechanical practice of rapidly reducing coarse sediment that enters the Yellow River. If the average check dam area ratio in the five typical catchments reaches 3.0%, the average sediment reduction ratio can be 60%. Therefore, in order to reduce sediment, especially coarse sediment that enters the Yellow River rapidly and effectively, the area ratio of the check dams in Hekou-Longmen Section should be kept at 3% or so. The two basins of Kuyehe and Huangfuchuan should be preferred as the main catchments that would reduce coarse sediment in the Yellow River.

Key words:typical catchments, check dam, coarse sediment, grain size