Macro - scale Hydrologic Simulation of the Source Regions of Yellow River Based on GIS

摘要

Hydrologic simulation strongly depends on the precision of underlay ground data and hydro- meteorological data. Hydrologic simulation of ungauged/spare gauged area now is a hot topic and many investigations have been conducted. W. Lahmer et al suggested transplant hydro - meteorological data from adequate gauged basin to ungauged area that those hydro - meteorological characters are similar. W. Larimer investigated the effect of uncertainty of hydro - meteorological input on the macro - scale hydrologic simulation and the results showed that the hydro - meteorological input data were vital factors in hydrological simulation. G. W. Kite and U. Haberlandt used the outputs of GCM as meteorological input to macro - scale hydrological simulation. Sten Bergstrooem and L. Phil Graham used a distributed hydrologic model to analyze the long - term time series runoff in Baltic basin based on the variable parameters, and the simulated results showed that the value of the parameters of the macro- scale hydrological simulation is relatively stable. Z. Micovic, M. C. Quick used the UBC hydrologic model simulated the snowmelt and rainfall runoff in ungauged area. Gupta investigated the event floods in macro - scale basin. Many works have been carried out related to the scale problem. Sivapalan and Wood analyzed the scale effect of hydrologic. Yet the hydrologic simulation of macro - scale ungauged area event flood is reported very little. The source regions of the Yellow River (the areas above Tangnaihai hydrologic station) with the area of 122 thousand km~2 still lack adequate hydro - meteorological data because of the unwelcome nature conditions. The multi - annual mean runoff of the source regions of the Yellow river is 20.400 billion m~3, which accounts for 35.3% of that Yellow River. The study regions are important runoff generation area of the Yellow River, in the 1990s, the Yellow River had experienced a serious runoff corrupt but the annual rainfall of the area didn't change significant. In this study, WMS (Watershed Model System) was chosen and HEC - 1 hydrologic model installed in the WMS was selected as to simulate 11 flood events. The study area was divided into 6 subbasins and the physical parameters of the subbasins were retrived from DEM (Digital Elevation Model). In every subbaisn the initial CNs (Curve Number) of SCS were assigned by land cover and soil type. For each simulation, the auto -parameter optimization tool installed in WMS 7.0 were used to calibrate the hydrologic model and for each subbasin and floods a CN retrieved. The uncertainty of CN was investigated into. The relative error of CN is linear with the mathematical expect experiential frequency.