SPILLWAY DESIGN PLAN FOR SADAWARNA DAM IN SUBANG REGENCY WEST JAVA

• Main Author: NA’IMA - NIM : 15813040 , NADRATUN
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/23412
• Institution: Institut Teknologi Bandung

Sadawarna Dam is located in Subang Regency, West Java with 345 km2 watershed areas and one of its main components is spillway. Spillway serves to ensure dam’s safety against overtopping by discharging excessive water. The purpose of this final project is to obtain the effective design and dimension and to ensure the spillway stability of Sadawarna Dam. The results of the rainfall distribution with Gumbel Method for 1,000 year return period is 162 mm/day and PMP is 305.14 mm/day. This spillway is designed by using Q1000 and controlled by using QPMF. The storage indication method is used to check the spillway capacity with the Q1000 discharge is 1,469.54 m3/s so that the flood water level that will spill is planned at +84 meter elevation and the dam crest at +87 meter elevation. The spillway is planned to be located at the main dam with selected type Ogee type spillway without doors. The spillway is designed with a width of 75 m. The transition channel and the chute channel are planned in rectangular shape with concrete and width of 40 m, while the trumpet channel has 45 m width. In accordance with the topographic conditions at the location of the spillway, the total length of from transition channel up to the trumpet channel is 165 m. The type of energy damper used is USBR type III. Modeling results by using HEC-RAS software shows that the dimensions of spillway, transition channel, chute channel, trumpet channel and energy damper have sufficient dimensions to encapsulate Q1000 and QPMF discharge. Stability calculation shows that the spillway is stable against the roll stability, shear stability and eccentricity in both flood water level and normal water level condition with earthquake and non-earthquake.