Effect of Climate Change on Long-term Riverbed Change using GSTARS Model in Nakdong River, Korea

Abstract

Changes in rainfall patterns due to climate change will change the hydrological elements in the stream and the riverbed changes that will occur consequently. In addition, dredging and multi-functional Weir installation was finished along the Nakdong River, South Korea in 2012 as a part of the Four Major River Restoration Project. Due to the project the river became wider and deeper with deeper water depth. If the characteristics of the watershed are maintained, it will return to the pre-maintenance stream, which is the dynamic equilibrium of the stream. Also, there are very few studies comparing and analyzing changes in river basins in connection with climate change. In this study, to develop the riverbed variation technique considering the climate change in the Nakdong River Basin. The fit of the model was analyzed by using GSTARS, which is a hydraulic model, by analyzing the changes of the riverbed according to the number of stream tubes and the sediment transport equation. As a result of the study, it was found that the riverbed change was appropriate when three stream tubes were used and the riverbed change was over estimated when the stream tubes were five. The Ackers and White and the Yang equations were found to be suitable for the riverbed changes. As the flow rate increases, the change of the riverbed becomes larger and the riverbed becomes narrower.