Korea's water resources exhibit a unique characteristic with up to 70% of annual precipitation concentrated during the summer season. In response to these climate characteristics, a climate adaptation strategy has been in place, designating the period from June 21st to September 20th as the flood season to prepare for potential floods. However, over the past 20 years, Korea has experienced a significant increase in extreme flooding, a consequence of shifting climate patterns that differ from the past, resulting in substantial damage. Therefore, this study statistically examines the increasing trend in precipitation and the reinforcement of regional precipitation characteristics using observational data from the 21st century. It has been proven that the current flood season does not adequately account for these changes. To address these limitations, this study proposed seven new flood season candidates, considering changes in the variables that were traditionally used as the basis for flood season determination, the rainy season and typhoon. To account for climate change adaptation, predicted inflow from the historic flood in 2020 was used as input data, utilizing the long short-term memory model, and applying the rigid reservoir operation method during modeling. Finally, all alternatives were evaluated based on whether they exceeded the design discharge of the dam and the design flood of the river. The results of the dam-based evaluation indicate that the application of the proposed flood season reduced the excess frequency and duration by 0.068% and 0.33%, respectively, while also reducing the magnitude by 24.6%. Evaluation based on river criteria also showed a decrease in the number of flood damage occurrences from 4 to 2. The findings of this study can serve as a basis for formulating flood adaptation measures in response to climate change through adjustments to the flood season.
