Page - 228 - in Book of Full Papers - Symposium Hydro Engineering

3.5. FLOOD ROUTING The result of flood design on Sengguruh Dam then calculated by flood routing in Q1000 th and QPMF to obtain outflow value from Sengguruh Dam (from spillway & turbine). The outflow result from Sengguruh Dam is then used as inflow discharge value for the calculation of river routing (Sengguruh-Sutami). The result value from river routing then combined with flood design from Remaining Basin Sutami to get the inflow value at Sutami Dam. The result of flood design in Lahor Dam then calculated by flood routing to obtain the outflow value at Lahor Dam. The inflow value of Sutami Dam then calculated by flood routing in Sutami reservoir by considering the in/out discharge from connection tunnel and discharge from hydroelectrical power plant of Sutami. The flood routing also considered the water level on PMF discharge so that the reservoir can still reduce the flood that occurred. Graphical representation of the calculations result can be viewed in “fig 8 and 9”. In order to obtain safety to manage at Sutami and Lahor Dam on possibility of overtopping caused by PMF discharge in the rainy season, the operation of Sutami and Lahor reservoir need to consider the application of CWL at elevation between +257,00 m to +267.00 m. Fig. 8 Water Level Elevation of PMF Discharge 228