基于DEM的大清河子流域划分方法

Study on Method of Sub-Basin Partition of Daqing River Based on DEM

针对流域水循环模拟中的子流域划分问题,以大清河流域为例,首先基于ArcGIS软件,以30 m分辨率的DEM作为数据源,进行填洼处理、流向判定、汇流累计量计算等;然后采用河网密度法和水系分维法确定最佳集水面积阈值,提取出与实际最符合的河网,以此更准确地提取流域水系;最后根据水流流向、汇流累计以及出水口的位置划分子流域,并基于MATLAB程序对子流域及其内部栅格进行编码。结果表明:当集水面积阈值为270 km^2时,提取的大清河流域河网水系与实际较为符合,且对子流域的划分及编码可以实现快速准确定位每一个栅格,方便计算机的识别及演算。因此,以DEM为基础实现大流域尺度下子流域划分是可行的,对子流域的划分及编码可以为开发构建大尺度流域分布式水文模型提供技术支撑。

Aiming at the sub-basin partition in the basin water cycle simulation, taking Daqing River basin as an example, based on ArcGIS software and taking the DEM with the resolution of 30 m as data source for depression filling, determination of flow direction and calculation of cumulative amount of confluence, this paper adopted the river network density method and water system fractal method to determine the optimal catchment area threshold and extract the most practical river network, in order to extract the drainage system of Daqing River basin more accurately. Finally, the molecular watershed was divided according to the flow direction, confluence accumulation and the location of the outlet, and MATLAB program was used for the sub-watershed coding. The results show that when the threshold of catchment area is 270 km^2, the extracted river network system of Daqing River basin is more consistent with the actual situation, and the partition and coding of sub-basins can achieve rapid and accurate positioning to each grid, which is convenient for computer identification and calculation. Therefore, it is feasible to realize subcatchment of large watershed scale based on DEM, and the coding of subcatchments can also provide technical support for the development and construction of distributed hydrological model of large watershed scale.