Evaluasi Sistem Drainase Menggunakan HEC-RAS pada Kawasan Kelurahan Bandar Selamat Kecamatan Medan Tembung Kota Medan (Studi Kasus: Jalan Letda Sujono Sekitar Pintu Tol Bandar Selamat)

Abstract

Bandar Selamat urban village, located in Medan Tembung District, is an area that frequently experiences inundation and flooding due to the inadequate capacity of its drainage system. The increasing intensity of rainfall, urban growth, and blockage of channels caused by sedimentation and waste have resulted in the existing drainage channels being unable to accommodate runoff discharge. This study aims to evaluate the performance of the drainage system on the North and South Main Channels along Letda Sujono Street by comparing their hydraulic capacity with the design flood discharge. The hydrological analysis was conducted using 10 years of rainfall data from BMKG Sampali Station through Log Pearson Type III frequency analysis, goodness-of-fit tests, rainfall intensity calculation, runoff coefficient determination, and the Rational Method. Furthermore, hydraulic analysis and simulations were performed using the HEC-RAS software to assess flow behavior and potential overflow conditions. The results indicate that several channel segments possess capacities lower than the design discharge, leading to potential inundation under certain return periods. Redimensioning of the channels is proposed to ensure that the drainage system can adequately accommodate the design flood discharge. This study is expected to serve as a technical foundation for improving drainage infrastructure within the study area.