Modeling Of Rainfall And Runoff Relationship And Estimation Of Influence Of Land Surface Change On Runoff In Suzhou

The basin rainfall-runoff relationship is a primarily concern in hydrological research. Investigation of the temporal and spatial variations is the key point for revealing rainfall-runoff relationship. It is important for both the flood disaster prevention and estimation of water resources.The characteristics of the Tai Lake hydrology include the complicated river network and frequent water movement which determines specific in rainfall-runoff relationship. The hydrological model including runoff generation and concentration in the Tai Lake basin was developed on the basis of the Xinanjiang model. The model was applied in the regions with four kinds of land surface conditions: water area, urban area, paddy field, and arid area. Rainfall-runoff relationship for each of the land surface condition was described in the model. A VB program was written for model execution. The model parameters were pre-set on the basis of land surface conditions in Suzhou, and adjusted on the basis of observed streamflow and stream stage data.Daily observed precipitation, pen evaporation and stream stage in the year of 1998,1999 and 2000 were used as model input. The simulated runoff process agrees with the stage changes, indicating more reliability of the model. The simulated runoff coefficients are 0.323,0.508 and 0.251 in 1998,1999 and 2000 respectively.The model was applied to analyze influences of the land utilization changes during 1986-2005 on runoff in Taitsang. The daily precipitation data in 1988 was used as a reference year for model execution in different land uses. Simulated results demonstrated that the total runoff increases from 229 million m~3 in 1986 to 239 million m~3 in 2005, and the runoff coefficient from 0.262 in 1988 to 0.331 for the rapid development of the urbanization.