流域坡面汇流研究现状述评

对当前坡面汇流计算方法的研究进展进行了较为系统的总结与分析,并对坡面汇流的非线性效应以及城市低影响开发中的雨水入渗与蓄集对坡面汇流的控制作用进行了简要分析。从模型简单实用的角度出发,认为以流域时间-面积关系与线性水库相串联的ModClark法等为代表的概念性分布式坡面汇流模型具有良好的发展前景;考虑到基于等流时单元的变动等流时线法在反映雨强非线性影响中存在的问题,认为根据水文响应单元在不同雨强条件下汇流时间的变化,调整其汇流参数以反映坡面汇流的非线性效应,对于流域坡面汇流的分布式模拟更具有实际意义;针对目前低影响开发设施长时间序列大空间尺度的室外降雨径流监测资料普遍较为缺乏的现状,给出了后期应积极选择合适的技术以加强低影响开发性能监测工作的建议。

Review on the simulation of overland flow in hydrological models

Overland flow is that part of rainfall which exceeds the infiltration capacity of the soil surface and any depression storage, which usually is assumed to flow downslope as a uniform thin sheet of water. In reality however, overland flow takes place along gullies and rivulets as non-steady non-uniform flow. It is one of the basic processes in the catchment hydrological cycle that has significant roles in processes such as soil erosion, sediment and pollutant transport. In this paper, different approaches of modeling and simulating overland flow including their pros and cons, assumptions and limitations are summarized and analyzed. From the literature survey, it can be concluded that the distributed conceptual approach based on the time-area relationship and linear reservoir has further development potential. In this study, a new approach based on the watershed variable isochrone method that uses the DEM and has the potential to represent the non-linear effects of the runoff generating mechanism is proposed. To implement this approach it is necessary to monitor runoff resulting from urban low impact developments (LID).