Study On Distributed Hydrological Model Based On GIS And DEM In Small Basin Of Deficient Data

In the hilly area,the geology and geomorphology of the small watershed is complicated,and the ability of flood detention is limited,and the river ratio is reduced,the convergence speed is fast,the flood is fierce,and the flood disaster is devastating.Due to the backward economic and technical conditions in hilly areas,small watersheds usually lack sufficient hydrological information and data.The traditional storm flood calculation method can not meet the needs of small watershed floods and flood disaster prevention.In the mountains without control of hydrological cross-It is impossible to carry out the river flood analysis and calculation.Coupled with the recent changes in global climate and the impact of human activities,more aggravated the lack of information area of small watershed flood defense difficulty.Therefore,it is very urgent and important to carry out research on hydrological phenomena and hydrological processes in small watershed in the area without information,and to minimize the loss of floods and floods.The distributed hydrological model is an important tool for people to understand and understand the hydrological cycle of nature and to solve all kinds o f hydrological problems.The distributed flood forecasting model is applied to the lack of data area and combined with modern technology and means such as DEM and 3S.The influence of spatial variation of rainfall and underlying elements on hydrological circulation in small watershed is the forefront of hydrological research.In this paper,the nonuniformity of rainfall and underlying surface conditions and the influence of rainfall intensity on the hydrological processes of small watersheds are considered,and a distributed hydrological model for small watershed is established.The results show that the Kriging method is suitable for spatial interpolation of rainfall in small watershed,and the accuracy of the rainfall is higher than that of the small rainfall.Secondly,the land use and soil type data and the extracted boundary of the river valley are superimposed to determine the land use and soil type of each grid in the basin,and provide the basis for the determination of the convergence speed.And then the traditional SCS model is improved to the grid-type SCS runoff model.The runoff model with distributed characteristics is formed.The flow velocity calculation formula should be considered based on the rain intensity.Calculation of Small Watershed Confluence by Theory of Spatial Velocity Field.Finally,we selected 15 floods in the Jinyu River Basin to verify the accuracy of the model.The results show that the deterministic coefficients of the flood simulation results are more than 0.7,of which 53.3% are larger than 0.9 and 33.3% are less than 0.9,which indicates that the model is reasonable and the rainfall runoff relationship of the small watershed is simulated Well,with high accuracy.Based on the distributed hydrological model constructed in this paper,the hydrological calculation of the small watershed in the lack of information area can be carried out to provide a new feasible means for the hydrological cycle research,hydrological calculation and flash flood forecasting.