Evaluasi Risiko Genangan pada Skenario Drainase Perkotaan Menggunakan Metode Rasional dan Pemetaan Kapasitas Saluran
DOI:
https://doi.org/10.51903/qg5d7x69Keywords:
Urban Drainage, Inundantion Risk, Rational Method, Channel Capacity, Manning EquationAbstract
The increase in impervious surfaces in urban areas can intensify surface runoff and increase inundation risk when drainage channel capacity is insufficient to convey the design rainfall discharge. This study aims to evaluate inundation risk in urban drainage scenarios using the Rational Method and channel capacity mapping. The study employed a scenario-based quantitative evaluative design involving five drainage channel scenarios representing variations in urban area characteristics, catchment area, runoff coefficient, channel dimensions, and channel slope. Runoff discharge was calculated using the Rational Method, while channel capacity was estimated using the Manning equation for rectangular open channels. The results show that S5 had the highest risk, with an inundation risk ratio of 0.8420, placing it in the moderate or critical category, whereas S4 represented the safest condition, with a channel capacity of 0.4624 m³/s and a risk ratio of 0.2735. These findings indicate that inundation risk cannot be assessed solely from runoff discharge or channel dimensions separately, but should be evaluated through the balance between runoff load and channel conveyance capacity. The scientific contribution of this study lies in developing a simple, quantitative, and replicable preliminary evaluation model to identify drainage scenarios that are safe, critical, or require priority intervention.
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