Water Balance and Flood Control by the Expansion of the Upo Wetland in Korea

In Korea, these days, there has been a growing interest in the washland as a function of flood control and also as an ecosystem in non-flood season. Therefore this study performs the hydraulic and hydrologic analysis for the construction of the artificial washland in surrounding area of the Upo wetland. A Topyung-cheon basin including the Upo is selected and a Topyung-cheon is one of the tributaries of Nakdong river, Korea. It is assumed that the artificial washland is constructed in upper stream and downstream of the Upo wetland. Actually, the construction of artificial washland can be considered as the expansion of the Upo wetland. HEC-RAS model is applied to estimate the reduction effect of flood stage in flood season as the artificial washland is constructed and compute the storage volume based on the low frequency precipitation(2yrs, 10yrs) for the investigation of water balance in non-flood season. The computed volume is used as the input data of AV-SWAT model. It is examined whether the storage volume can be sufficient to support the artificial washland environmentally. As a result, it can be shown that the flood control effect of the artificial washland is not big and the storage volume is sufficient to maintain the artificial washland at upstream and downstream of the Upo wetland. From this result, it is thought that the ecological aspect for the expanded wetland according to the variation of water in flood and non-flood seasons can be considered later.