中文摘要：

基于二维运动波模型,建立了一个适用于小流域场次降雨产汇流过程的动力学模型。通过对典型小流域内不同区域（坡顶、坡中及坡底区域及距离流域出口的远近）种植植被时产流过程的数值模拟,分析了小流域内植被分布对产流过程的影响。结果表明：植被分布及其特性对小流域场次降雨产流有较明显的影响;下游区域种植植被的减水效果和延滞洪峰作用优于上游区域,陡坡区域减水效果优于缓坡区域,且郁闭度越大,这种差别越明显;在该研究条件下,下游区的减水效果可达到上游区的3倍;30%郁闭度条件下减水效果可达10%和20%郁闭度条件下的3倍和1.4倍。

英文摘要：

The distribution of vegetation in small catchments is an essential factor determining the generation of runoff during rainstorm events. Using a novel two-dimensional dynamic runoff model,we studied the influence of the distribution of vegetation on rainstorm runoff. First,a kinematic hydrological model of rainstorm events in small watersheds was developed based on a two-dimensional overland flow model. It included canopy interception,surface infiltration,overland flow,and gully flow processes. Data from three rainstorm events in the Heicaohe catchment were then used to verify the model,and good agreement was found. Last,the model was used to examine how the distribution of vegetation and the canopy density affected the runoff process. Model results showed that： First,the vegetation significantly reduces flood discharge and postpones the flood peak,depending on the location and crown density of the vegetation.Second,the efficiency of runoff reduction is substantially higher in downstream and steeply sloped areas（ vs. upstream and gently sloping areas）,and the degree of crown closure enhances this effect. In fact,in this study,the efficiency of runoff reduction was three times higher in downstream compared with upstream areas,and 30% crown closure resulted in 1. 4 times higher efficiency than 20% closure and three times higher than 10% closure.