Abstract:

The STREAM is a cell based distributed hydrology model,which can be used to give insight in the complex impacts of climate change and hydrological characteristics change of land surface on hydrological cycle using easily accessible geographic information.Xitiaoxi watershed in Taihu Basin was selected as the study area,precipitation data of 26 rain stations from 1979 to 1999 and land use data of different years were collected.Data of watershed grids map in 300 m cellsize for STREAM model were constructed by watershed analysis and spatial interpolation methods of GIS.Using BLAISE scripts language,the STREAM model was established and integrated with Idrisi GIS software.The model is calibrated well and valid using monthly runoff data from 1979~1999.Results showed that the modeled monthly and annual runoffs match well with the observed ones.In the calibration period of 1980~1988,the efficiency value is 0.78 for monthly runoff and 0.86 for annual runoff.The relative mean error of annual runoff is about 6%.In the validation period of 1989~1999,the efficiency value is 0.75 for monthly runoff and 0.82 for annual runoff.The relative mean error of annual runoff is about 9.5%.The case study proved that the model works well for runoff prediction and has better application prospect in the watershed management.

Key words: distributed hydrological model, STREAM, Xitiaoxi watershed, water balance