Study Of DEM Resolution On The Influence Of Hydrologic Nianzishan Basin Simulation

The study of the hydrological cycle process is always the focus of research in the field of hydrology.The hydrological cycle process is a complicated process which includes multiple physical processes.The mechanism has not yet been revealed.Hydrologists generally used method of abstract and reasonable estimate of the established model to simulate this process.Developers of U.S.Army Corps of Engineers developed the HEC-HMS model.Characteristic of the model is that it includes multiple module processes of the hydrologic cycle which provides different calculation methods for each physical module.According to the actual situation of the watershed,different modules can be selected to combine to calculate.So that the HEC-HMS model is widely applicable.In this paper,we take Nianzishan watershed of Heilongjiang Province as the research watershed,we collected the rainfall and runoff data in the watershed,sorted out the 7 corresponding screenings of rainfall runoff processes.First we use the HEC-GeoHMS to pretreated 5-meter resolution DEM data of Nianzishan watershed.Extracting watershed hydrological parameters and using HEC-HMS hydrological model to establish the calculation model.Set the initial value of hydrological parameters,and then choose initial abstraction steady infiltration method,SCS unit hydrograph method and Muskingum method to combine and calculate.The results computed by the simulation schemes show that,the passing rate of flood-peak was 100%,the passing rate of depth of runoff was 58%,The average of certainty coefficient was 0.85.HEC-HMS model perform well in Nianzishan watershed.On the basis of the previous model simulation,we both use the HEC-GeoHMS to pretreated 30-meter and 100-meter resolution DEM data of Nianzishan watershed and establish two different calculation models.The two calculation models set the same initial value of hydrological parameters as the 5-meter resolution model and use the calculation to compare with the 5-meter resolution model.According to the comparison,We find that DEM resolution does have a certain impact on HEC-HMS simulation,the flood-peak,depth of runoff and certainty coefficient are all different.The larger the grid is,the smaller the peak time is.The resolution of DEM data is smaller,the certainty coefficient is better.