STUDY OF MORPHOLOGY OF SERANG RIVER ESTUARY FOR FLOOD CONTROL OF NATIONAL STRATEGIC AREA YOGYAKARTA INTERNATIONAL AIRPORT (KSN YIA)

• Main Author: Separnu, Dibo
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/62774
• Institution: Institut Teknologi Bandung

Yogyakarta International Airport which has been designated as a National Strategic Area is geographically located in the lowlands which is flanked by two main rivers, namely the Bogowonto River on the west side and the Serang River on the east side. The Serang River experiences flooding almost every rainy season, one of the factors that causes flooding in the Serang River is the condition of the Serang River estuary which is covered by sedimentation. This condition causes a backwater effect which results in an increase in the flood water level, besides that the condition of the Serang River estuary which is covered with sediment can cause a decrease in the storage capacity of the Serang river during a flood. This study conducted a backwater analysis at the Serang River estuary which was carried out by modeling the HEC-RAS 6.1 program and then studied the morphological changes of the Serang estuary due to hydrodynamic influences on the Glagah beach using the Delft-3D 4.04.02 program. The results of the analysis of the existing conditions of the Serang River cannot accommodate the flood discharge of Q100 and with the influence of the tides it causes a water level rise of 2.14 m at the Serang River estuary to 0.15 m at a distance of 1.8 Km from the Serang River estuary, due to the backwater effect there is an increase in flood water level of 0.66 m at the Sungai Carik Timur outlet. The hydrodynamic effect on the Glagah beach causes sedimentation in the Serang estuary with a thickness of 3.5 m in the west monsoon with an area of 0.063 ha and in the east monsoon 4 m with an area of 0.437 ha.