设计暴雨雨型对高植被覆盖流域径流形成影响的数值模拟

Numerical Simulation of the Influence of Design Rainstorm Pattern on Mountain Torrent Disaster in High Vegetation Coverage Basin

为分析设计暴雨雨型对山区小流域山洪灾害的影响,应用时空变源混合产流模型,以四川省关口、汉王场为研究区域,分析高植被覆盖流域对不同重现期以及不同设计暴雨雨型条件下降水的响应规律,并对不同雨型及重现期条件下流域的洪峰流量、峰现时间、洪峰滞后时间等量值进行对比分析。结果表明:时空变源混合产流模型在高植被覆盖流域洪水模拟应用过程中能够取得较好的模拟精度,具有一定的适用性;关口、汉王场流域同一重现期条件下偏后型雨型相对于偏前和居中型条件下形成的洪峰流量更多,但偏前型雨型相对于居中型和偏后型雨型而言形成的洪水总量更大;在不同雨型条件下,随着重现期的增加,关口、汉王场流域的洪峰流量均是呈现增加的趋势;林草植被覆盖率为汉王场>关口流域,关口流域在不同重现期设计暴雨雨型条件下的峰现时间均是提前于汉王场流域,林草植被覆盖对于洪水的径流过程具有一定的调节作用;关口流域和汉王场流域洪峰出现时间相较于暴雨雨峰出现时间的滞后时间均为偏前型>居中型>偏后型;揭示西南山区高植被覆盖流域对于不同重现期设计暴雨雨型条件下的量化规律,在分析西南山区高植被覆盖流域暴雨洪水的形成过程、提高流域洪水预报精度与防洪减灾能力方面具有指导意义。

In order to analyze the impact of rainstorm design on mountain torrent disasters in small watersheds in mountainous areas,this paper uses a spatio-temporal variable source mixed runoff generation model,taking Guankou,and Hanwangchang in Sichuan Province as the research area,the response rules of descending water in high vegetation cover basins to different reproduction periods and rainstorm type conditions of different designs are analyzed,and the peak flow,peak present time and peak lag time of the river basin under different rain types and recurrence period conditions are compared and analyzed.The research findings show that the spatio-temporal variable source mixed runoff generation model is suitable for the simulation of hydrological processes with good simulation accuracy in mountainous areas with high vegetation coverage.The latter rain patterns in the Guankou and Hanwangchang basins have more flood peaks than those formed under the front and middle conditions under the same recurrent period,but the front rain patterns produce more floods than middle and rear rain patterns.Under the conditions of different rainfall patterns,with the increase in return period,the peak discharge of the Guankou and Hanwangchang drainage basins shows an increasing trend.The forest and grass vegetation coverage rate is Hangwangchang>Guankou watershed,and the peak emergence time of the Guankou is earlier than that of the Hangwangchang watershed under the design rainstorm conditions of different return periods,the vegetation coverage of forest and grass can regulate the runoff process of flood to a certain extent.The lag time between the occurrence time of the flood peak and the occurrence time of rainstorm peak in the Guankou watershed and the Hanwangchang watershed is forward type>middle type>rear type.Revealing the quantitative law of the high vegetation covered watershed in the southwest mountain area for the design of rainstorm patterns in different return periods has a guiding significance in analyzing the formation process of rainstorm and flood in the high vegetation coverage basin of the southwest mountain area,and improving the flood forecasting accuracy and flood control and disaster reduction capability of the basin.