Comparison of 1D, hybrid 1D-2D, and 2D modeling for Dam-break Flow: case study Way-Ela Dam, Indonesia

Abstract

Dam-break events are extremely dangerous and cause hazardous floods to the downstream area. To reduce the damages, an evacuation plan is needed, which can be devised by means of dam-break analysis. This study analyzes the flood inundation area with hydraulic numerical modeling consisting of 1D, hybrid 1D-2D, and 2D models. As a case study, a dam-break event of the Way-Ela dam in Indonesia that occurred in 2013 is selected. The Way-Ela dam that was a natural dam and formed by landslides in 2012 due to heavy rainfall, failed in 2013 caused by piping after a heavy rainfall case. The analyzes of hydraulic modeling are done to produce inundation area, water level, and velocity of the flood. The comparison results will be represented with 5-pointed location in the inundation area. After the numerical analysis was done, the accuracy of each model was discovered by validating the results with the observed data. The analysis was conducted with HEC-RAS software. The results showed that the 2D model produced the most accurate results.