ALTERNATIVE DESIGN FOR THE SPILLWAY STRUCTURE OF PAMUKKULU DAM, TAKALAR REGENCY, SOUTH SULAWESI

• Main Author: Zaky Ibnu Malik, Muhamad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/82737
• Institution: Institut Teknologi Bandung

Pamukkulu Dam is located in Ko’mara, North Polombangkeng District, Takalar Regency, South Sulawesi. One of the components of the Pamukkulu Dam is the spillway structure, which functions to release excess water from the reservoir to ensure it does not exceed the design capacity, which could cause damage to the dam. The hydraulic design planning of the spillway is a crucial part of designing the dam, especially for embankment dams. The spillway structure is planned to be located beside the dam. It is designed as an overflow type with an Ogee crest, complete with supplementary structures such as the transition channel, chute channel, and energy dissipation structure. The spillway design planning involves stages of hydrological, hydraulic, and stability analysis. Extreme weather conditions are used as a reference for calculations in designing the Pamukkulu Dam spillway. Probable Maximum Precipitation (PMP) represents the greatest rainfall that can occur in an area and is determined using the Hersfield method. The inflow discharge used is the Probable Maximum Flood (PMF) discharge. The Synthetic Unit Hydrograph (SUH) method selection was conducted using the Creager method, and the chosen method was ITB-1b. Flood routing calculations were performed using the HEC-HMS 4.11 application. From the hydrological calculations and flood routing results, the planned inflow flood discharge QPMF is 1685.9 m³/s, and the outflow QPMF is 1341.6 m³/s. These results are used in the hydraulic analysis to plan the spillway dimensions. The hydraulic calculation results show that the spillway width is 85 m with a water height above the crest of 3.7 m. The stability analysis of the spillway structure is controlled for overturning and sliding. Through the stability analysis of the spillway crest against overturning and sliding forces under normal water levels and floodwater levels, it can be concluded that the Pamukkulu Dam spillway structure is safe against these forces. The construction of the spillway has a Budget Plan (RAB) of Rp. 93.61 billion.