基于DEM的分布式汇流模型及其在洪水预报中的应用

Distributed Flow Routing Model Based on DEM and Its Application in Flood Forecasting

基于数字高程模型,并结合国外在河网水系提取的研究成果,归纳出提取河网水系的方法,并将其应用于实际的水系提取。建立了流域尺度的概念型分布式新安江模型,该模型在栅格单元中采用新安江模型作产流计算,根据单元的不同属性(坡地、河道)及所推求的汇流时间场建立汇流模型。将此模型应用于淮河黄泥庄以上集水区域,对黄泥庄站的洪水过程进行了模拟研究,模拟结果符合洪水预报的规范要求。

Spatial variability of topography within a basin has a great impact on runoff. An automatic extraction of drainage network algorithm based on digital elevation model (DEM), was generalized according to the definition of drainage structure. The studied basin was decomposed into grids and every grid was defined as hillslope unit or river unit by the algorithm. Then a constant flow velocity was assigned to each cell and the time lag between cell input and response at the basin outlet was calculated. The velocity field was assumed to be time-invariant and spatial-variant. So an isochrone map was showed. The subbasins for flow concentration were compartmentalized by it. The Xinanjiang model was set up and at the same time different flow concentration model was constructed according to the difference of grids (hillslope grids and river grids) within each grid. Such a hydrologic model is a conceptual distributed Xinanjiang model (CDXAJM). Examples were presented for Huangnizhuang subbasin of Shiguanhe basin in Huaihe drainage area in which the CDXAJM is applied. In this simulation, weather radar rainfall was used as precipitation input and the simulated flood process of Huangnizhuang hydrological station was reasonablecompared to the observedone.