基于Nash瞬时单位线法的渗透坡面汇流模拟

基于Nash瞬时单位线法,结合Horton土壤入渗经验模型,并考虑植被对降雨的截流作用,建立了渗透坡面汇流计算的数学模型。以矩形坡面为研究对象,基于其汇流时间-面积特性,推导建立了Nash瞬时单位线参数n、K的确定方法。其中参数n的值与坡面汇流时间-面积曲线指数相等,K的值与坡面汇流时间相等。应用本文建立的模型,对林地渗透坡面降雨径流进行计算,并与实测值进行比较。结果表明,计算值与实测值的变化趋势基本吻合,初步验证了本文方法的合理性。

Simulation of rainfall runoff on permeable slope based on Nash instantaneous unit hydrograph

Based on Nash instantaneous unit hydrograph, Horton infiltration equation, and rainfall interception models, a math model to simulate the rainfall runoff on permeable slope is established. The time-area relation of basin is a concentrated expression of geomorphic characteristics. Based on the time-area relation and isochrones of watersheds, a determination method of parameters n and K for Nash instantaneous unit hydrograph is derived in rectangular basin. The value of parameter n is equal to the exponent of time-area curve, and the value of K is equal to the routing time. Finally, the model is applied and examined in simulation of rainfall-runoff on forested permeable slope in Miyun Reservoir watershed area in Beijing. The result shows that the trend of the calculated and measured values are consistent well.