Estimation Of Velocity Field And Unit Hydrograph Based On The Watershed Spatial Information Integration

In recent years, with the acceleration of industrialization, disasters appear more frequently,urban flood disaster has brought great harm to human life and production, flood control work is urgent to people who research on it. Since the powerful function of spatial information collection,classification,management and analysis of Remote sensing(RS) and geographical information system(GIS) technology, they have been widely used in actual application such as water quality, flood forecasting, disaster risk assessment and so on.This paper focuses on the spatial information integration theory and key technology of GIS and RS — data integration and related function integration, combined with the corresponding hydrological model and unit hydrograph model, finally to be used in the acquisition of spatially distributed velocity field and unit hydrograph of a watershed. We take a sub basin of Tangbaihe Basin as a typical, fully consider the underlying surface inhomogeneity and based on the above integration theory meanwhile, a research on the study area is conducted.The initial research contents and results are as follows:(1) Apply relevant GIS and RS integration theory and technology to land use classification of remote sensing image classification, search the same processing unit of GIS and RS and integrate corresponding data and function of them, so that the GIS data can be a part of the remote sensing image processing data. GIS image processing results can provide supplementary information for remote sensing image processing to improve the accuracy of remote sensing image processing.(2) Combined with drainage semi distributed hydrological model under the integration of spatial information, first of all is the hydrological analysis based on the digital elevation model(DEM), considering the influence of underlying surface factors like slope and land use type on the basin simulation, then distinguish overland flow and channel flow according to different calculation formula of hydrological model. Finally, we get the spatially distributed velocity field.(3) Combine the above velocity field result with distributed unit hydrograph model, usingthe grid as a processing unit, according to flow path and velocity field data to obtain the time-area curve, which is a key element to determine the spatial distributed unit hydrograph of watershed.(4) From the derivation of watershed spatial distribution of velocity field and unit hydrograph, make use of further development component of GIS — ArcGIS Engine to accomplish a modularized design of our research. It provides a structured studying framework and a clear visual display, what's more it will do favor to offer technical support to the early warning system of basin.The integration of watershed model and spatial information can simplify the complicated hydrological phenomenon, the obtained spatially distributed velocity and unit hydrogaph also has a great significance in providing decision-making information and technical support to subsequent work such as watershed hydrological monitoring, forecasting and so on.