Estimations of Flood Potential Risk and Frequency for a Region

The Potential Flood Damage(PFD) is widely used for representing the degree of potential of flood damage in Korea. However, this cannot be connected with the design frequency of river basin and so we have difficulty in the use of water resources field. Therefore in this study we develop the concept of Potential Risk for Flood Damage Occurrence(PRFD) which can be related to the design frequency. The PRFD has three important elements of hazard, exposure, and vulnerability. The hazard means a probability of occurrence of flood event, the exposure represents the degree that the property is exposed in the flood hazard, and the vulnerability represents the degree of weakness of the measures for flood prevention. The elements also have some sub-elements. Say, the hazard is explained by the frequency based rainfall, the exposure has two sub-elements which are population density and official land price, and the vulnerability has two sub elements which are undevelopedness index and ability of flood defense. Each sub-elements are estimated and the estimated values are rearranged in the range of 0 to 100. the Analytic Hierarchy Process(AHP) is also applied to determine weighting coefficients in the equation of PRFD. We estimated the PRFD for the Anyang river basin, Korea and also the design frequency by using the maximum rainfall. The exiting design frequency for Anyang river basin is in the range of 50 to 200 years. And the result of this study is in the range of 110 to 130 years. Therefore, we can use the developed method for the estimation of PRFD and the design frequency for the administrative districts and maybe we could apply the method for the watershed and the river channel in the future study.