SWAT-Aided Research About Simulation Of Runoff And Hydrological Response To Ecological Restoration

The degradation of ecosystems in Longxi Loess Plateau of China is becoming increasing serious, it has caused great menace to local people's life and production, In order to ease the environmental crisis, the ecological restoration is needed. We hope to provide scientific reference and decision-making gist for the project of the ecological restoration in this region through the simulation research of the hydrological response for the ecological restoration.Limited by the adverse natural environment and the laggard economy and technology conditions, the basic datum of the hydrology, weather, agriculture and soil are lean in this area. The research of hydrology and water resource currently in this area is scarce. At the same time, as the analyzing technology of the hydrological response for LUCC variation is still in the preliminary development stage and the prediction research of the future LUCC variation influencing hydrology is just beginning, there is no relevant report about the research of the hydrological response for the method of ecological restoration.In view of the above mentioned fact, the distributed hydrologic model of SWAT (Soil and Water Assessment Tool) developed by USDA was applied to simulate the runoff of the Nanhe River Basin in Huajialing, assisted by the RS and GIS technology. According to the result of the simulation, we has probed the best way to perfect and resume eco-environment through simulating the variation trend of runoff and actual evapotranspiration in different situation of ecological restoration.In order to guarantee the watershed delineation level to be in the high point for this watershed and make the adjustment of model calibrating parameters be more reasonable. In this research, we also analyzed and estimated the sensitivity of the cutting delineation level of subwatersheds and hydrologic response units, and the sensitivity of inputted parameters to the result.We also appraised the applicability of SWAT model in Longxi Loess Plateau inthe research. We got a conclusion: in some years when the precipitation per year appears to be sudden increase and the absolute value of kurtosis coefficient of the precipitation per month appears to be much more high, the result of the runoff depth per year simulated by the SWAT model would be abnormal, with the situation of boasting the increasing extent of the precipitation and making the simulating value per year of runoff several times than the actual measuring value, these years named abnormal-high-value-years in this research. At the same time, as the abnormal-high-value-years exists the continuity, this directly leaded to the greater integral error of the full period simulating result. So when simulating the runoff relevant, we'd better avoid these years.