IJASEIT

International Journal on Advanced Science, Engineering and Information Technology, Vol. 8 (2018) No. 6, pages: 2413-2420, DOI:10.18517/ijaseit.8.6.7489

The Use of GIS and Hydrodynamic Model for Performance Evaluation of Flood Control Structure

I Gede Tunas, Rizaldi Maadji

Abstract

Flood disaster in Palu River has repeatedly occurred with varying discharge magnitudes, especially in the downstream segment near and around the estuary. The most recent flood occurred in July 2018 has inundated some areas of Palu City and resulted in a considerable impact on the socio-economic life of the community in the city of Palu. Actually, flood prevention efforts have been undertaken by the Palu City Government and River Basin Board of Sulawesi III, one of which is by constructing levee combined with revetment along more than 5 km measured from the estuary to the upstream reach. The levee is made of soil material, while the revetment is a structure to protect the levee made of concrete. These structures were built on both sides of the river banks. However, the flood disaster always happens almost every year in this area. This paper intends to evaluate the performance of the flood control structure using Geographic Information System and HEC-RAS hydrodynamic model. The use of these tools provides the ease and efficiency of flood simulation along the river being modeled. The analysis results show that the bank capacity of Palu River is currently only effective for flood discharge below 550 m³/s, where the river bank capacity at the beginning of the levee and revetment design is approximately 550 m³/s, equivalent to the 25 years return period of discharge. The river bank capacity decreases due to sediment deposition on the river bed which were originated from the upstream watershed. This decline in cross-section capacity is estimated to be the cause of the flood disaster in parts of Palu City.