Studi Perbandingan Kapasitas Aliran & Resiko Banjir Sungai Wulan Dengan dan Tanpa Sistem Pembagi Debit

Abstract

Demak Regency frequently experiences flooding during the rainy season due to the limited capacity of the Wulan River to accommodate high water discharge. This study aims to evaluate the river's capacity to handle flood discharge and identify critical points. The research utilizes hydraulic modeling with HEC-RAS software, using geometric data collected along an 11.95 km stretch from Wilalung Sluice Gate to Tanggulangin Bridge. The area is divided into three segments: the main Segmen, Wilalung Segmen, and left Segmen. A flood discharge of 1,100 m³/s is used as the primary scenario, while a diversion simulation to the Juana River, reducing the discharge to 700 m³/s, is also conducted. Results show that at 1,100 m³/s, several stations (STA) indicate significant overflow potential: STA 226 (3,58 m) in the main Segmen, STA 235 (3,58 m) in Wilalung Segmen, and STA 234 (3,57m) in the left Segmen. After diverting the discharge to 700 m³/s, most points remain safe, although STA 234 remains critical at 3,20 m. In conclusion, river normalization and structural measures at critical points are needed to minimize the risk of flooding.