Hydrodynamic Modelling of Juwana River Flooding Using HEC-RAS 2D

Abstract

On the equator, Indonesia had very complex geographical, geological, hydrological conditions. It was also traversed by three large plates namely the Eurasian plate, the Indo-Australian plate, and the Pacific plate. Because of the colliding meeting of the three plates, the territory of Indonesia had a variety of topography ranging from hills, mountains, plateaus, lowlands, and basins. The basin found in the Juwana watershed caused frequent flooding every year due to the overflow of Juwana River. The river passed through Kudus and Pati. In the last ten years there had been 179 floods in Juwana River. This study aimed to examine the discharge and distribution of floods based on the return period of floods 2, 5, 10, 25, 50 and 100 years. The research method used was frequency analysis, snyder synthetic unit hydrograph analysis, and hydrodynamic modelling using HEC-RAS 5.0.6 2D (two dimention) with unsteady flow. The findings indicated that on the return period of floods 2, 5, 10, 25, 50, and 100 years, the discharge and distribution of floods were 1169.2 m3/with the inundated area of 22898.54 Ha, 1401.7 m3/with the inundated area of 25558.51 Ha, 1541 m3/with the inundated area of 26916.42 Ha, 1704.9 m3/with the inundated area of 28411.52 Ha, 1819.9 m3/with the inundated area of 29905.85 Ha, and 1930 m3/with the inundated area of 30785 Ha respectively.