The Influence Study on the Basin´s Runoff Yielding from the Precipitation Change - A Case Study in Zhelin Basin

With the intensification of global change, the influence on basin runoff resulting from precipitation change has become more and more severe. This paper studies the influence of the runoff as a result of precipitation change and takes a case study in Zhelin basin with the help of the SWAT model to simulate the runoff. The study items include the month´s average precipitation, and the simulated runoff by SWAT model during the years 2000-2004, with the year of 2002 as a case study to analyze the influence on the runoff from the seasonal precipitation change. The simulated result shows that the precipitation has an obvious influence on the runoff, and the runoff changing trend is in accord with the precipitation changing trend, although not a linear relationship, which could be affected by the other factors, such as the temperature, the water consumption, solar radiation, and the wind velocity, etc., especially the influence of the summer monsoon and the plantation water-consumption. The result also shows that with an increment of precipitation, the influence on runoff yielding from the overlaying would be less.