Fachrul Madrapriya ,ST., M.PSDA Dosen Pembimbing 1 MUHAMMAD REZA NURFAUZAN / 222023609 Penulis

The Sayung Industrial Area in Demak Regency frequently experiences inundation of ±30 cm due to its flat topography (elevation 0-2 meters above sea level) and upstream runoff loads. This study aims to evaluate the performance of the existing drainage system and determine the required pump optimization using hydrological analysis and HEC-RAS hydraulic modeling. The hydrological analysis employed the Rational Method with a 10-year return period design rainfall based on the Gumbel distribution, while rainfall intensity was calculated using the Mononobe method. The results show a rainfall intensity of 56.51 mm/hour, generating a total upstream design runoff of 0.98781 m³/s. At the junction, the flow load entering the Left Pantura Channel is adjusted to 0.494 m³/s. Hydraulic modeling of the downstream section indicates that under existing inundation conditions, the channel has an effective capacity of only 0.33 m³/s. Consequently, there is a flow capacity deficit of 0.164 m³/s, preventing gravity-based drainage. Optimization is achieved through increasing pump capacity to handle this deficit and managing operation patterns based on critical water level elevations to effectively control inundation.