基于代表性单元的流域水沙耦合模型及其应用

构建适用于宏观尺度的流域水文模型和模拟流域泥沙输移是流域水文模拟技术和理论的重要研究内容,流域水沙耦合模拟是其中的重要问题。本文以适用于宏观尺度的代表性单元流域水文模型为基础,引入泥沙的侵蚀和运移过程建立了水沙耦合模型,通过对水沙运移过程中河道坡度变化的模拟,实现了真正意义上的水沙耦合模拟。为了解决二叉树结构的河道编码方式不能处理三条支流汇合的局限,在模型中使用了虚拟计算单元。使用高精度的遥感影像资料量取河道宽度,然后拟合河道宽度和汇流面积的相关关系,从而确定各计算单元河道宽度,为缺资料地区的水文模拟提供了一种方法。结果显示,水文模拟效果很好,输沙率的模拟值与实测值相比在输沙总量和年内过程方面都非常吻合,流域河道坡度整体上稳定,但是局部河段仍处于演化过程中。

Tsinghua hydrological model based on representative elementary watershed coupling sediment and its application

The establishment of the watershed hydrological model at the macro-scale and the simulation of the sediment delivery in the catchment are the key research issues in the watershed hydrological modeling, in which the coupling simulation of the water and sediment in the watershed is the key issue. On the basis of the hydrological model based on Representative Elementary Watershed which is applicable to macro-scale, the paper introduces the sediment erosion and delivery to build up the water-sediment coupling model. With the simulation of the changing channel slope in the water-sediment delivery, the model achieves the water-sediment coupling modeling in nature. To deal with the limitation of the channel coding of binary tree, the virtual computation unit is used into the model. The high-resolution remote sensing image is employed to measure the river width and it provides a new method for the hydrological modeling in the ungauged basins. The results shows that, the performance of the hydrological modeling is very good, and simulated and observed sediment discharge are consistent in terms of total sediment load and intra-annual process. Most of the channel slopes of the watershed are steady and parts of the reaches are in the evolvement.