Of Dem-based Distributed Hydrological Model And Applications

Spatial heterogeneity of physiogeographical components leads to spatial and chronological changes of hydrological process in watershed. These effects can be taken into account by distributed hydrological model with DEM. The distributed hydrological model can simulate the physical process of rainfall-runoff in watershed more actually, and maybe improve the accuracy of simulating further. At the same time, the rapid development of GIS, RS and computer affords powerful function for applying the distributed hydrological model into watershed.Firstly, taken the upriver watershed of Isere as an example, which is the anabranch of Rhone River in France, this paper makes a digital terrain analysis. Using GIS tools including Workstation and DeskTop of ArcInfo from ESRI, the digital analysis of catchments properties from DEM is studied, such as the extraction of river network, boundary of subcatchments and distributed catchments characters.Then, the water yielding and runoff routing theory are studied, and a DEM-based distributed hydrological model is established. This model is composed of two parts: runoff yielding module and water routing module. The former bases on the hillslope hydrology and puts emphasis on the effects of terrain which denoted with topographic index for each grid. The water routing process is expressed with Gamma function importing a delay time parameter which can be calculated simply from river travel.To test the model, the author chooses fourteen rainfall-runoff processes between 1998 and 2002. After comparing the simulated process with the observed data, we can draw a conclusion that the proposed distributed hydrological model in this paper is reasonable for simulating rainfall-runoff process.