复杂侵蚀环境下分布式土壤流失水动力学模型——以黄河多沙粗沙区为研究实例

Distributed Hydrodynamic Model for Complex Erosion Environments——A Case Study in the Rich and Coarse Sediment Area of Yellow River Basin

以黄河多沙粗沙区为研究对象,基于实体模型试验对黄土坡面-沟道系统侵蚀产沙机理的认识,根据侵蚀动力学、水文学、泥沙运动力学的基本理论,以地理信息系统为平台,研发了复杂侵蚀环境下的分布式土壤流失水动力学模型;揭示了植被作用下坡面-沟道系统侵蚀产沙耦合规律;认识到坡沟产沙之间具有内在的自调控关系;提出了当量糙率的概念;建立了基于G IS的分布式土壤流失水动力学模型;构建了基于ArcG IS平台的支持系统,实现了G IS与土壤流失模型、产汇流模型与产输沙模型的紧密耦合。通过实例验证了模型对于中尺度流域土壤流失的模拟亦有较满意的精度。

On the basis of the analysis of the erosion and sediment yield mechanism of hill slope-gully surface erosion system by physical model experiments, the basic theories of erosion dynamics, hydrology and sediment transport mechanics, the distributed soil loss model and support system for complex erosion environments were developed by GIS in the rich and coarse sediment area of the Yellow River basin. The coupling relation of erosion and sedi- ment yield of hill slope-gully side erosion system under vegetation effects was disclosed. The conception of ＂equivalent roughness＂ was put forwarded. The distributed hydrodynamic model for soil erosion based on GIS was established, which close couples the GIS, soil loss model, runoff produced model, sediment yield and transport model. Also, the support system based on ArcGIS was developed. By two illustrations, the simulated results obtained using this model for larger water bain soil loss were examined.