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| Influence of soil and water conservation on sediment budget of channel system:A case study of the Wudinghe River Basin |
| Xu Jiongxin |
| Institute of Geographical Sciences and Natural Resources Research,Chinese Academy of Sciences,Key Laboratory of Water Cycle and Related Land Surface Processes,Chinese Academy of Sciences,100101,Beijing,China |
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Abstract A fluvial system can be divided into two sub-systems,i.e.,hillslopes and channels.For the two sub-systems,sediment budget can be established separately.The results show: 1) After the implementation of soil and water conservation,all components of the sediment budget of channel system of the Wudinghe River Basin varied markedly.Channel sediment delivery ratio decreased significantly,and sediment storage in gullies and river channels increased significantly.Sediment yield of drainage basin decreased sharply,but net erosion from hillslopes decreased mildly.2)The contribution of soil erosion control measures and high-flow season rainfall(P6—9) to the variation in various components of sediment budget have been estimated,using multiple regression analysis.For the variation in net erosion on hillslopes,the contribution from P6—9 is estimated as 90.82%,and that from hillslope soil conservation measures is only 9.18%.However,for the variation in sediment storage in gully and channel system,the contribution from sediment trapping by check dams is estimated as 76.16%,and that from P6—9 is only 23.81%.For the variation in sediment yield of drainage basin,both the variations in rainfall and in sediment and soil conservation played important roles.For the variation in sediment yield of drainage basin,the contribution from P6—9 is estimated as 57.84%,and that from sediment and soil conservation is 42.16%.3)For the variation in channel sediment delivery ratio,the contribution from sediment trapping by check dams is estimated as 87.27%,but that from P6—9 is only 12.73%.
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Received: 29 January 2008
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