Runoff Simulation And Response To Climate Change In Upper Boyang River Basin Based On SWAT Model

In this research, a distributed hydrological model—SWAT is used to simulate stream flow on a monthly time step in Upper Boyang River Basin. This research provides important reference to rational allocation of water resources and technical guarantee to realize water sustainable use and water quality improvement in Boyang River.Based on climate, digital elevation model, soil, land use and cover data, Boyang River upper basin is divided into 23 sub-basins and 135 hydrological response units in total. On the basis of original database in SWAT mode, this research establishes a simulation model in study area. Using sensitivity analysis module in SWAT model, we get six sensitive parameters mainly affecting runoff process, and completed model calibration and validation with measured stream flow data during 2006-2007 and 2008-2010 respectively. Simulation results show that linear regression coefficient R2 of average monthly flow in calibration and validation period is 0.86 and 0.85, Nash-Sutcliffe efficiency coefficient Ens is 0.85 and 0.83 respectively, it can be founded that all evaluation indicators meet requirements. This research indicates that SWAT model has good simulation ability and effect; it can be used to model rainfall runoff process in Boyang River basin. Finally, supposing different scenarios of future climate changes and re-establishing meteorological database, this research applies calibrated SWAT model to simulate hydrological respond to climate changes. Results show that the monthly and annual average flow reduced with decreasing precipitation and increasing temperature, and the influence of precipitation changes to runoff is more greatly than temperature change...