Abstract
Frequency-Damage (FD) method is a statistical analysis for evaluating flood risk curves based on long-term flood damage records. In this study, we propose an improvement of existing FD method that can take account of the years without any disaster damage in a small municipality. By applying existing FD and improved FD method to Japanese municipalities, we were able to show two distinct advantages of the improved FD method. First, improved FD method decreases over and under estimation of the expected value of flood risk compared with the annual average flood damage loss. Second, it reflects more accurately the probabilistic characteristics of flood risk. Therefore, it expands applicability from regional to smaller domains up to basic municipalities. This new method can be used for investigating the regional differences of flood risks and the flood risk characteristics of municipalities.
