농업소유역 설계강우의 임계지속기간 적용성 분석

Abstract

The Keifer and Chu rainfall time distribution model has been used in the inundation analysis for agricultural basins. However, for applying the critical rainfall duration, the Huff series model is needed for the time distribution model. The purpose of this study was to analyze the applicability of critical rainfall duration in agricultural basins according to the rainfall time distribution model and rainfall duration. For this purpose, peak discharge, inundation level, and storage ratio were simulated with different design drainage in four study sites. For the rainfall time distribution model, this study applied the modified Huff model and the Keifer and Chu model. In the simulations, the Keifer and Chu rainfall time distribution model simulated a continuous increase in both peak flow and inundation level with increasing rainfall duration, which made the critical rainfall duration inapplicable. However, the modified Huff model was able to apply the critical rainfall duration. The modified Huff model had 2 4 hours of critical rainfall duration based on the peak discharge and storage ratio, and had longer than 4 hours based on the inundation depth. As the critical rainfall duration with the inundation level was longer (exceeding 4 hours), less inundation damage will be simulated with shorter rainfall durations. Therefore, it would be more appropriate for agricultural basins to apply critical rainfall duration based on inundation levels rather than peak discharge or storage ratio. The results of this study are expected to serve as a basis for research on applying critical rainfall duration in agricultural watersheds.