Lee, G., Kim, J. and Jun, K.S., 2013. Estimation of probable flood discharge in tidal river using unsteady flow model

A method for estimating the probable flood discharge using unsteady flow model was developed. The method consists of two steps. Firstly, the unsteady flow model is applied to the current stream condition to simulate the peak discharge for each historical flood event. Then, the probable flood discharge is calculated by conducting a frequency analysis on the annual maximum series or partial time series of simulated peak discharges. The proposed method avoids the estimation of the probable rainfall and application of a rainfall-runoff model, and the accompanying uncertainty can thus be eliminated. The proposed method was applied to the main stream reach of the Han River in South Korea. The downstream reach of the Han River is greatly influenced by strong tidal variations, and it has another unique feature in that it contains two submerged weirs—Jamsil and Singok. The unsteady flow model was developed by modifying the existing FLDWAV model so as to model the characteristics of the Han River in the context of computational river hydraulics. Historical flood events were simulated and the probable flood discharges along the river reach was computed through partial duration series frequency analysis.