No abstract

This study has evaluated the stream gauge network with the main emphasis on the methodology of optimal stream network which is considered the discharge characteristics between upstream and downstream. To evaluate the optimal stream gauge network, the representative unit hydrograph which is considered the discharge characteristics between upstream and downstream is transferred into probability density function for application of the entropy concept. This study has been compared the case of considering discharge characteristics between upstream and downstream and the case of the conventional methodology of using empirical formula and applied to the Chungju dam basin. Summarizing the results are as follows. It can be found that the large total information content is estimated at the case which is considered discharge characteristic between upstream and downstream more than the case which is applied empirical formula even though the few stream gauge stations is selected. It means that the total information of selected stream gauge stations is represented well the discharge characteristic between upstream and downstream. The Chungju dam basin is found to need at least 12 stream gauge stations, which was derived by considering the discharge characteristic between upstream and downstream.

The data of stream gauging stations connected to the upper and lower stream have similar hydrological characteristics. It is also very important data for disaster management. In this study, we suggest a methodology which is used to build an optimal stream gauge network for mitigating the flood risk of a disaster risk area by adding new stream gauges at disaster risk areas to the existing stream gauge network. The upper stream basin of Geum river was selected as a study area. Representative unit hydrograph was estimated by Clark method in each station. And the information transmission by entropy analysis were evaluated based on the log-normal distribution. The optimized stream gauging networks about three scenarios of the gauging stations were determined using the entropy theory. Finally the most important gauging station was selected using the received information transmission in each disaster risk area and the whole basin.