Study On Calculation Method Of Flood In Mountainous Area

Small valley,mountain hydrological stations distribution of low density,often lack sufficient hydrological data and data,and because of the influence of human activities,many watershed underlying surface situation happened great changes,and these areas tend to be around to carry out the work of flood control in key areas.In this paper,we mainly discuss the problem of how to make full use of the existing data to small watershed runoff concentration calculation,research on this problem can not only improve hydrology theory,but also provide necessary basis and support for the prevention and control of flood.The Lushan County,Henan Province as the background,through collecting and processing by taking small watershed as the unit of hydrology,topography,and other basic information;using GIS,satellite remote sensing and other advanced technologies,extraction data related to modern hydrological model;on the basis of the results of mountain torrents disaster investigation,analysis of storm and flood in small flow domain,the main contents and conclusions are as follows:(1)an overview of existing methods and results for the calculation of small watershed flood at home and abroad.The design flood calculation and the flood area composition are discussed.In the calculation of design flood,in addition to the reasoning formula method and the unit hydrograph method,Britain and the United States mainly use regional frequency analysis,including regional regression method and regional impact method;China more than a regional comprehensive method and empirical formula,provinces are compiled set of corresponding hydrological manuals and figure,for engineering design and calculation.(2)in Lushan County is China’s flood disaster prevention focus County,according to the data characteristics of Lushan County by a directly based on unit hydrograph of watershed topography and vegetation characteristics calculation method and the theoretical basis of the method for basin water confluence time probability density distribution function number are equivalent to the line of the unit.The basic idea of calculation method: first analysis calculation of small watershed in the grid diameter flow residence time,then according to the routing path to get each runoff reaches the convergence time of the small watershed outlet,the final calculation of concentration time of the probability density distribution and the geomorphological unit hydrograph.(3)respectively in Lushan County of the Yao Shan Zhen Ying pan Gou Cun Huang Tu Gang,Tang Zhen Zhu Yuan Gou Cun Yao Gou group as an example were runoff concentration calculation,and verify the results of calculation of flood,geomorphological unit hydrograph method and rainstorm Atlas method at the flood process simulation verification I have derived: geomorphological unit hydrograph method to simulate the flood process closer to the measured data of flood process.