Simulation of flood inundation in the Klawing Watershed, Purbalingga, Central Java

Abstract

The initial phase of flood disaster management necessitates the identification of inundated areas. Employing numerical calculations in flood inundation simulations offers distinct advantages, primarily in its capacity to craft scenarios for assessing the efficacy of implemented measures. The flood inundation in the Klawing watershed was simulated numerically using HEC-RAS 5.0.7. Upstream boundary conditions were incorporated, employing all estimated extreme flood hydrographs across various return periods: 2 years, 5 years, 10 years, 25 years, 50 years, 100 years, and 1000 years. The disaster mitigation infrastructure for the Klawing River watershed should be planned considering potential flood damages across a range from low to very high. The sensitivity of the inundated area to various return periods of the flood hydrograph suggests that this can be achieved by utilizing flood hydrographs with return periods of 5 years, 10 years, 25 years, 50 years, and 1000 years, respectively.