中文摘要：

以辽宁白石水库库区大凌河与牤牛河交汇流河段为例，基于模型试验，研究了干支流不同遭遇洪水所产生淤积量与淤积分布．结果表明，受到水库蓄水、支流牤牛河来沙量较大等因素影响，库区交汇河段发生淤积，而干支流洪水不同遭遇对淤积量及其分布影响十分显著：干支流洪水同时发生时交汇区淤积量最小，淤积主要集中在支流河段，淤积厚度沿程减小；干流洪水先于支流发生时交汇区淤积量最大，淤积厚度沿程先增大后减小；干流洪水晚于支流发生时，淤积发生在干流河道与交汇区内，表现出淤积范围大但厚度较小的特点．

英文摘要：

Under different flood encounter cases, the siltation character in confluence river reaches is unlike the situation in single channel in reservoir area. Based on the confluence of Daling River and Mangniu Riv er in Baishi reservoir, the paper investigates the deposit volume and distribution under different cases by using physical model test. The results show： due to the impoundment and huge sediment transportation from tributary, there was always silting in the river confluence reaches, while the orders of mainstream flood and tributary flood affected the result notably. When two rivers flood occurred at the same time, the siltation volume were least and mainly in the tributary, deposit thickness decreased along the channel. If the mainstream flood occurred earlier, deposit volume in confluence region is greatest among all these cases; and its thickness first increases then decreases. If the mainstream flood came after the tributary flood, the deposit concentrated in mainstream channel and confluence region, revealed the features of large range of siltation but smaller thickness.