Inflow Analysis into Bili-Bili Reservoir

Abstract

Bili-bili Reservoir was built with the main objective of controlling flooding in Makassar City. With a flood control capacity of 41 million m3 with an initial capacity of 347.82 million cubic to 239.76 million cubic due to increased sediment in the reservoir so that if there is high rainfall it has the potential to cause flooding. The research entitled “Inflow Analysis to Bili-Bili Reservoir”, has a problem formulation of how the relationship between rainfall and inflow (discharge) entering the reservoir and how the comparison between inflow based on rainfall data and AWLR (Automatic Water Level Recorder). The purpose of this study was to analyze the relationship between rainfall and inflow discharge into the reservoir and to compare the inflow discharge based on the results of rainfall analysis with the inflow based on AWLR. This study uses secondary data from the Pompengan Jeneberang River Basin Center (BBWS). The regional average rainfall analysis used the Thiessen method, while the Synthetic Unit Hydrograph (HSS) Gama I method was used for flood discharge analysis. For flood discharge analysis, the maximum annual rainfall was selected according to the maximum inflow recorded at the Bilibili Dam AWLR. From the calculation of the HSS Gama 1 parameter, the rise time is 2.72 hours and the peak ordinate is 10.290 m3/second. When compared with the inflow (discharge) data on the Bili-Bili AWLR, the results of the calculation of the discharge with HSS Gama I are smaller in value with a difference of 20.50% to 31.46%.