长江上游河流泥沙近期变化、原因及减沙对策——嘉陵江与金沙江的对比

Status and Causes of Sediment Change in the Upper Yangtze River and Sediment Reduction Measures ——Comparison of Jialing River with Jinsha River

嘉陵江和金沙江是长江上游的两条重要来沙河流。嘉陵江流域地形起伏小，植被恢复和水土流失治理的减沙量足以抵消工程建设的增沙量，加之降雨偏少，９０年代输沙量明显减少。金沙江上游是少沙区，天然林采伐对主河输沙量影响有限；下游多沙区地形起伏大，工程建设增沙量远大于植被恢复和水土流失治理的减沙量，８０年代以来，金沙江输沙量呈增加的趋势。建议狠抓预防监督，严格执法，减少工程建设增沙。金沙江下游区，要完善小流域治理措施配置，重视沟底林建设和考虑修建拦沙工程或具有拦沙效益的水利水电工程。要加强对长江上游侵蚀泥沙，特别是金沙江下游区工程建设增沙的研究。

Jialing river and Jinsha river are two main sediment sources to the Yangtze river in the upper reaches. There have been evident deduction of sediment delivery in 1990s in Jialing river because of smooth landscape, less rainfall, and re plantation of vegetation and soil and water conservation which can counteract sediment increase caused by project construction in the basin. The upper Jinsha river is the region of less sediment yield with limited influence of primeval forest cut on stem sediment transport, while the lower Jinsha river is of rough landscape with far more sediment production from project construction than the sediment retention through re plantation of vegetation and soil and water loss control. There has been increasing sediment transport in the river since 1980s. Therefore, it is suggested that strong effort should be put on prevention, monitoring and strict law enforcement to reduce sediment increase by project construction. In the lower Jinsha river, watershed management treatment should be perfected, reforestation on gully bed should be strengthened and sediment retention dams or hydro power projects with sediment reduction benefit should be paid attention. Research about erosion and sediment in the upper Yangtze River should be enhanced especially about sediment increase by project construction in the lower Jinsha river.