Analisis Kinerja Saluran Dengan Simulasi HEC-RAS (Studi Kasus Desa Air Putih Kecamatan Bengkalis)

Air Putih Village in Bengkalis District is a lowland area that frequently experiences flooding, particularly around the Poros Sungai Alam Road. Flooding occurs due to the inadequate capacity of the drainage channels to accommodate high rainfall, compounded by tidal influences (ROB) from the sea. This condition disrupts community activities and poses significant potential losses. This study aims to analyze the performance of the drainage channels in accommodating the design flood discharge through hydraulic simulation using HEC-RAS software. The design flood discharge was calculated using the Rational, Weduwen, Haspers, and Nakayasu methods for 5-year and 10-year return periods. The calculated discharge was then simulated in HEC-RAS 1D (steady flow) and 2D (unsteady flow) models, including a scenario combining flood discharge and tidal influence (ROB). The data used include historical rainfall records, topography from the Digital Elevation Model (DEM), and the geometry of the existing channels obtained from field surveys. The results show that the existing drainage channels are unable to accommodate the 10-year return period discharge. In the 1D simulation, the maximum inundation area reached 0.16310 km² (Q5) and 0.17743 km² (Q10). In the 2D simulation with ROB, the inundation area increased to 0.3392 km² (Q5) and 0.3841 km² (Q10). The largest inundation occurred at Q10 with ROB, affecting residential areas and local roads. Recommended measures include channel normalization, additional drainage channels, retention ponds, floodgates, and an integrated drainage system plan.