The Study Of Spatial Variability Of Rainfall And Its Effects On Runoff Response

The temporal and spatial variability of rainfall and the spatial variability of the watershed characteristics (infiltration, hydraulic conductivity and vegetation etc. ) is one of the sources of the rainfall-runoff simulation complexity. Accurate simulation , analysis and evaluation of the temporal-spatial variability of rainfall are required for the water resource manage, expecially flood forcasting, runoff simulation and water quality prediction. Geostatistics method and a planar stochastic rainfall simulation model were applied to analyse the spatial variability of rainfall in Luanhe Basin, and runoff response due to spatial variability of rainfall in Sahe Basin. Some conclusions were drawed:1. Based on geostatistics methodology, the spatial variability of day rainfall in Luanhe Basin was investigated .We found that the spatial variability in day rainfall had different law in the different scales , and the spatial variability in the small scale can't be neglected.2. The influence of density of rainfall-gauges network on the precision in the interpolation of rainfall with Kriging technique was studied. It indicated that the curve of the variation of interpolating precision by kriging with the network density approximately put up a logarithm law.Further research showed that the kriging variance and the coefficient of variation (Cv) can be used to predict the precision of kriging.3. Through combinating of Geostatistics method , spectral method and a two-dimension stochastic rainfall simulation model proposed by Saha , a conditional and unconditional rainfall simulation model for modelling the rainfall in the SaHe Basin was built.4. Syncretizing the idea of Monte Carlo, the influence of spatial variability of rainfall on rainfall-runoff modeling was investigated, focusing on the important rainfall-runoff modelling factors : volume of storm runoff ,peak runoff ,time-to-peak.At last, all the work were summarized ,and the deficiency of the paper was pointed out , and several suggestions for future study were brought forward. .