Research Of Grid Distributed Hydrological Model With Incompact Structure And Geomorphological Instantaneous Unit Hydrograph

The relative merits and applicable conditions of several popular methods of rainfall spatial interpolation are discussed. Considering the influence of topography to rainfall, the coKriging method with consideration of altitude influences is introduced into rainfall spatial interpolation. Several methods are applied to spatial interpolation for several rainfall spatial patterns with different time scale in Yanduhe basin, including Thiessen polygon method, distance square reciprocal method, ordinary Kriging method, and coKriging method proposed by this article. The last one proves to be best.A grid distributed hydrological model with incompact structure is built on the basis of the theory of runoff formation on repletion of storage. The computing methods of rainfall input and runoff generation and flow concentration in grid elements are discussed deeply. The co-Kriging method considering the altitude influences is applied to get the rainfall in grid elements. The vegetal cover and landuse conditions in regions of interest are acquired from remote sensing data. The function relationship between the maximum of soil moisture deficiency and topography index is given. The flow concentration paths of net rainfall in every grid element are gotten from DEM, which solve the problems of rainfall input and parameters grided. The model is applied to the Yanduhe basin in Three Gorges of Yangtse River and is compared to the lumped Xinanjiang model. The better results are gotten finally.Considering the spatial changes of hydrodynamic parameters are neglected in existing GIUH theory, the concept of equivalent path hydrodynamic parameters based on geomorphologic diffusion and hydrodynamic diffusion is suggested. The GIUH considering the spatial changes of hydrodynamic parameters is established. Considering the self-similarity of river networks, self-similar network of ideal river networks is constructed and the width function computation method of formed networks is derived by fractal method. The method corrects the irrationality of the former method, accumulative width function is used to determine the best fit network. The GIUH based on the width function considering the spatial changes of hydrodynamic parameters is built, by which the results of flood routing of watershed are satisfactory.