山区公路沿线小流域划分及流域特征分析

以重庆市巴南区安澜、跳石两镇主要公路干线为研究对象,采用大比例尺地形图为基础数据建立公路沿线数字高程模型,基于ArcGIS水文分析模块通过DEM填洼、水流方向分析、汇流累积量计算、河网提取等对研究区公路沿线进行小流域划分,并分析其流域特征。研究表明:研究区集水栅格阈值为15 000时提取的水系与实际河网最接近,以此将研究区划分为87个小流域,其中公路通过31个小流域。在31个小流域中,有58.06%的小流域面积在1～5 km2之间;小流域形状系数在0.32～4.96之间;小流域起伏度在121～535 m之间;各小流域到达公路最大汇流累积量在46～759 348之间。

Division and Features of Small Watershed along Mountain Roads

Taking the main arterial road of Anlan and Tiaoshi in Chongqing Ba'nan District as the research projects,the large scale topographic map is used as basic data to build digital elevation model along roads.On the basis of ArcGIS hydrological analysis module,some studies are carried out to divide the small watersheds along the mountain roads and analyze the watershed features,such as the DEM filling,flow direction analysis,confluence accumulation calculation,extraction of river network and so on.The research results show that the extracted water system is most approximate to the actual river nets when the set water grid threshold value is 15,000;and then the research areas are divided into 87 small watersheds,in which the road passes 31 watersheds.In the 31 small watersheds,the areas of the watersheds accounting for 58.06% are between 1and 5 km2;the shape coefficients of the small watersheds are between 0.32 and 4.96;the undulation of small watershed is between 121 and 535 m;the biggest confluence accumulation of small watersheds which cross the road is between 46 and 759,348.