等流时线

然后，结合传统的流域汇流方法&等流时线，综合考虑地形和降雨在空间分布上的差异性对径流汇流的影响，提出流域的变等流时线方法。

Secondly , with reference to the traditional flow routing method & isochrones , spatial variability of rainfall and watershed topography are both considered to derive the variable isochrones .

在数字水系基础上推求的变等流时线，避免了传统等流时线假设流速在全流域均匀分布的缺陷，综合考虑了地形和降雨空间分布的差异性对汇流流速的影响。

The variable isochrones based on digital stream networks , can overcome the defect in traditional isochrones method , which assumes that flow velocity is even on the whole watershed . The influence of rainfall and watershed topography on flow routing can be both considered in the variable isochrones .

同时还提出了两种汇流模型：基于栅格的Muskingum逐栅格演算法和基于子流域的等流时线汇合法。

Meantime , two models of flow routing and confluence are established , including the Grid-Based Muskingum Flow Routing Method and the Sub-basin-Based Isochrone Method .

计算机辅助绘制流域等流时线

Computer aid drawing of equivalent flow duration contour

基于数字高程模型的流域变动等流时线方法

Watershed variable isochrones method based on DEM

最后，用变等流时线建立流域的汇流模型，并将其应用于一个缺乏资料的小流域。

Lastly , a digital flow routing model has been established based on variable isochrones and the proposed variable isochrones method has applied for a small watershed .

应用变等流时线进行流域的汇流计算，不但能够反映地形地貌对汇流的影响，而且能够较好地反映暴雨中心空间位置的变化对洪水流量过程的影响。

By using variable isochrones to compute the discharge hydrograph , the influence of watershed topography can bepresented , and the influence of rainfall can also be better reflected .

其中，流量子模型采用瞬时暴雨强度描述降雨过程、区域综合径流系数计算扣损以描述产流过程、等流时线原理描述汇流过程；

The runoff sub-model describes the rainfall event with instantaneous rainfall intensity , the runoff-generated event with runoff coefficient of integrative area and the runoff converged event with the principle of equal time of flowage .

等流时瞬时单位线汇流模型

Confluence model of isochronic instantaneous unit hydrograph