찌따룸 강 상류 Majalaya 지역의 홍수위험도 분석을 통한 단계별 경보수위 설정 연구

초록

This study aims to quantitatively assess flood risk in the Majalaya area of the upper Citarum River basin, Indonesia, and to establish stage-based alarm levels and evacuation criteria. The flood risk analysis was conducted by integrating the HEC-HMS rainfall-runoff model and the HEC-RAS 2D hydraulic model to calculate the inundation depth and area by return period, thereby quantifying the risk for each stage. The HEC-HMS model estimated design discharges for return periods of 2, 25, 50, and 100 years by applying Log-Pearson Type III frequency analysis and the Huff fourth-quartile temporal distribution. Concurrently, the HEC-RAS 2D model simulated the inundation extent, depth, and velocity through the numerical analysis of two-dimensional unsteady continuity and momentum equations. The simulation results revealed that the inundated area expanded approximately 9.5-fold, from 163.59 ha for the 2-year return period to 1,550.15 ha for the 100-year return period, while the mean inundation depth increased from 1.2 m to 2.1 m. Based on a comparative analysis of the Indonesian PUPR guidelines, the Rating Curve methodology, and the Korean flood warning criteria, the levee-height ratio approach (Option 2) was selected as the optimal alternative due to its superior reflection of local hydrological characteristics and suitability for the CBDRM framework. By applying this selected option, a three-stage alarm system consisting of GREEN (Caution), YELLOW (Alert), and RED (Danger) levels was established. Furthermore, this system was compared and analyzed against Korea’s fourstage flood warning system (Attention, Caution, Alert, and Serious) to ensure its effective application as a reliable basis for CBDRM action plans.

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