Daily-Scale Runoff Simulation of Shanxi Drinking Water Based on SWAT Model, Using Separation Dry and Wet Season Calibration Method

In this study, by establishing a daily scale SWAT model with dry and wet seasons separated in the study area, the sensitivity and uncertainty of parameters in the typhoon-affected area are discussed. At the same time quantitative analysis of the temporal and spatial characteristics of water resources. The results show that 1) the sensitivity parameters in the dry and wet seasons are very different. The most sensitive parameters are ALPHA_BF.gw and CN_2.mgt, but the least sensitive parameters are SURLAG.bsn and GWQMN.gw, respectively. This is obviously related to the meteorological conditions of the two periods. 2) Uncertainty analysis shows that the uncertainty of model parameters is mainly caused by extreme daily runoff parameters. 3) Except that the NSE and R2 of the wet season model are slightly lower than 0.7, the NSE and R2 of the dry season are higher than 0.73, and the PBIAS in both periods is within 10%. This shows that the application of separate calibration methods improves the accuracy of the model. 4) The correlation between wet season precipitation and runoff is higher than 0.98. The average wet season runoff for many years accounts for 81.44% of the annual runoff, which is the main period of runoff generation. The key source area of runoff is 51.04% of the total area of the river basin, and the runoff flow accounts for 54.21% of the total runoff of the land. It should be protected.