溪洛渡库区牛栏江河口泥沙淤积特征研究

Sediment deposition characteristics of Niulan River Estuary in the Xiluodu Reservoir

金沙江下游溪洛渡水库蓄水运行后,改变了库区入汇支流的下边界条件,导致库区支流河口普遍淤积,水动力条件发生变化,进而可能影响支流河口区域的水生态环境。针对溪洛渡库区最大的支流牛栏江,根据实测水文、泥沙、断面和地形资料,分析牛栏江水沙变化的特性,揭示其河口段的泥沙淤积特征。分析结果表明,2014-2020年,牛栏江河口段累计淤积泥沙296万m^(3),深泓平均淤积抬高9.4 m,局部形成倒比降,河口淤积的泥沙主要来源于流域产沙,伴随象鼻岭等规划梯级建设运行和水土保持治理,河口进一步大幅淤积形成拦门沙坎的可能性较小。

After the impoundment and operation of the Xiluodu Reservoir at the lower reach of Jinsha River,the lower boundary conditions of the tributaries entering the reservoir area changed,leading to general deposition at the estuary of the tributaries in the reservoir area.The changes of local hydrodynamic conditions affect the water ecological environment in local areas.The study takes Niulan River,the largest tributary of Xiluodu Reservoir Area,as the object,and analyzes the characteristics of water and sediment processes in the Niulan River according to the measured hydrological and sediment data and section data,to reveal the characteristics of sediment deposition in the mouth reach of Niulan River.The results show that from 2014 to 2020,the Niulan River Estuary has accumulated 2.96 million m^(3)of sediment,and the thalweg has been deposited up by 9.4 m on average,forming an inverse gradient locally.The sediment deposited in the estuary mainly comes from the basin.With the planned cascade construction and operation of Xiangbi Ridge in Niulan River,as well as the water and soil conservation and control in the main sediment produce areas,it is less likely that the estuary will be further deposited up to form a sand bar.