The Flood Forecasting Research Of Lijiang River Upstream Based On TOPMODEL

Now middle or small catchment flood forecast is one of the key problems of hydroscience. The Lijiang River upstream is one of the rainstorm centers in Guangxi province. Frequent storm flood disasters have caused serious loss. This paper focused on the research of the flood forecasting scheme of Lijiang River upstream.The TOPMODEL flood forecast model of the Lijiang River upstream digital watershed has been built based on DEM and GIS platform. The parameters of the model has been analyzed. Finally the model has been applied to study basin.In the digital watershed construction, based on Arcgis, the AGREE algorithm is used to repair the DEM and to extract some digital watershed information such as flow direction, slope, rivers, sub basin, etc. It will also extract topographic index and isochrones of the whole basin and 11 sub basin by Arcgis and D8 algorithm. Based on the platform of visual studio 2010, we program the TOPMODEL calculator program of Lijiang River upstream by C#. GLUE method will be applied to analyze the sensitivity of main parameters and applicable scope of main parameters will be gained by uncertainty analysis in different types of floods. So the main parameter applicable scope in study basin will be defined by comparison and analysis.We have selected 22 floods from 2008-2012 as the floods in calibration period and 10 floods from 2013-2014 as the floods in validation period to simulate rainfall-runoff process of Lijiang River upstream based on sub basin with the information of rainfall and evaporation. The results show that, in calibration period, flood forecast accuracy level is 86.3% and the average deterministic coefficient number is 0.814 in 20 floods. For 10 floods, the qualified ratio is 80% and the average deterministic coefficient number is 0.825 in validation period. The results have reached the precision level of Serie B in Hydrological forecast, which show that we can apply the TOPMODEL model prediction scheme to the actual flood forecast work of Lijiang River upstream.