Abstract: The spatial distribution characteristics of runoff in Wushan County under different rainfall scenarios were simulated based on GIS, which provided a basis for disaster prevention, mitigation and emergency management of runoff flood in mountain area. Taking Wushan County of Chongqing as the research area, based on the SCS model, coupled with the data of land use and soil type, the rainfall runoff simulation was carried out and was divided into 5 grades, according to 8 scenarios of 24-hour rainfall, including 50, 75, 100, 125, 150, 175, 200 and 250 mm, which was started from the three scales such as the whole, township and highway. The results show that: (1) With the increase of rainfall intensity, the runoff gradually changes from grade I to grade II~V. The high-level runoff zones mainly distribute in zonal distribution in the middle and south of the study area, and distribute in cluster in the northwest of the study area. The total runoff has increased by 26.35 times, and the overall growth rate continues to decrease. (2) The average runoff of Guandu Town, Dachang Town and Wuxia Town in the study area is more than 100 million m3, which is vulnerable to floods, mudslides, landslides and other disasters. Therefore, key prevention and control should be carried out in flood season. (3) The total amount of road runoff in the study area has increased by 17.91 times, and the runoff of western roads and a few roads in the east is large, which is easy to cause road interruption due to flood disaster. (4) When there is a heavy rainstorm, the highway runoff of Dachang Town, Guandu town, Wuxia town and other towns in the study area is V-grade, which is the section with high rainfall runoff and flood disaster. The multi-scenario simulation of rainfall runoff based on SCS model can better represent the spatial distribution of rainfall runoff, and the calculation results can be used for disaster prevention, mitigation and emergency management.

Key words: hydraulic engineering, SCS model, rainfall runoff, scenario simulation, highway flood, Wushan County

摘要： 基于GIS模拟不同降雨情景下巫山县径流空间分布特征，为山区径流洪水防灾减灾及应急管理提供依据。以重庆市巫山县为研究区，从整体、乡镇、公路3个尺度出发，基于SCS模型，耦合土地利用、土壤类型等数据，按照24 h降雨量50、75、100、125、150、175、200、250 mm等8种情景进行降雨径流模拟并划分为5个等级。结果表明：随着降雨强度不断增加，径流量由I级逐渐向II~V级转变，径流量高等级区主要呈带状分布于研究区中部、南部，呈团状分布于研究区西北部，径流总量增加了26.35倍，整体增幅不断减小；研究区官渡镇、大昌镇和巫峡镇平均径流总量高于1000.00万m3，易遭受洪水、泥石流、滑坡等灾害影响，在汛期应进行重点防治；研究区公路径流总量增加了17.91倍，西部公路及东部少数公路径流量较大，易发生洪灾造成道路中断；当发生特大暴雨时，研究区大昌镇、官渡镇和巫峡镇等多个乡镇部分公路径流为V等级，为降雨径流洪水灾害高发路段。采用SCS模型进行降雨径流的多情景模拟能较好地表征降雨径流量的空间分布，计算结果可用于防灾减灾及应急管理。

关键词: 水利工程, SCS模型, 降雨径流, 情景模拟, 公路洪灾, 巫山县