Abstract
This study aims to analyze the effect of sedimentation on the drainage channel capacity on Jalan Letda Sujono, Medan Tembung District, Medan City. The frequent flooding problem in the area is thought to be caused by sediment accumulation that reduces the drainage channel's flow capacity. The study was conducted using field survey and hydrological analysis methods. Primary data were obtained through direct measurements on 10 channel segments with a total length of 451 meters, including channel width, channel depth, water depth, and sediment thickness. Sediment samples were also taken to determine material composition. Secondary data in the form of annual maximum rainfall for 2010–2023 were used for the design rainfall analysis using the Gumbel method. Population projections were calculated using arithmetic and geometric methods to determine the increase in domestic wastewater production entering the drainage system. The results showed that sediment thickness in each segment varied and was dominated by sand and mud, which reduced the effective cross-sectional area of the channel. This condition affects the channel's capacity to drain water discharge, especially during high-intensity rainfall. In addition, increased design rainfall and population growth are expected to increase the volume of runoff and domestic wastewater entering the channel. Therefore, sedimentation control and regular maintenance of drainage channels are necessary to maintain flow capacity and reduce the risk of flooding in the research area.