Runoff Simulation and Analysis in Upstream Dagu River Watershed Using a Distributed Hydrological Model

The distributed hydrological model, SWAT, was used to study the seasonal and interannual variation of the runoff in upstream Dagu River watershed and the governing processes as well. The model output is sensitive to five parameters (e.g., Cn2, Esco, and Sol_Awc). The modeled result shows maximum monthly runoff occurring in August and minimum in February, consistent with the observation. The average annual runoff depth is about 83 mm, with strong interannual variability. The runoff depth was deep in the eastern and western areas, while it is relatively shallow in the southern and northern area. Furthermore, the impact of land use/ land cover change on runoff yield was also discussed.