Metode Hidrograf Satuan Sintetis (HSS) Laksono-Erub untuk Banjir Rancangan pada Sungai Plumbon

The Plumbon River is the main river in the Plumbon watershed located in Semarang City, Central Java Province. The Plumbon watershed has an area of ± 32 km2, and the length of the main river is ± 20 km. In this river, floods frequently occur, causing water to overflow the embankments and leading to their breach. Given these conditions, it is necessary to apply the best method for analyzing the design flood discharge on the Plumbon River, ensuring that the planning of structures along the river aligns with the actual field conditions. The Synthetic Unit Hydrograph (HSS) methods used include the Nakayasu, Snyder, Gama I, and Laksono-Erub methods, along with the calculation of the design flood discharge using the recorded discharge at the Plumbon Weir. Based on the calculations and analysis of the design flood discharge in the Plumbon watershed, the Laksono-Erub HSS method was determined to be the most effective, as it showed the smallest deviation from the discharge data recorded at the Plumbon Weir over the past 10 years.