Development of Java Island-scale Flood Model using CaMa-Flood

Abstract

Java Island is one of the most densely populated islands in Indonesia, with a total population of 152 million. The continuous population increase has led to a rise in disaster vulnerability, including flood disasters. Since 2012, the frequency of floods has continuously increased, with an average annual rise of 13.18%. Global-scale-river models were developed to evaluate the effects of runoff forcings on food hazard, droughts, and water resources management. Indonesia, including Java Island, has limitations in data storage and management, resulting in some areas having inadequate data for flood modelling. The Java Island-scalefloodmodel was developed using satellite-based runoff data as the primary input. The model enabled historical flood reconstruction on the entire Java Island, which was chosen due to the frequent and increasing flood incidents. The modelling system uses the Catchment-based Macro-scale Floodplain (CaMa-Flood) version 4.2.0 river hydrodynamics model, which simulates hydrodynamic processes at a resolution of approximately 1 km. The CaMa-Flood simulation is driven using daily simulated runoff from the Earth2Observe (E2O) model, a global river map from MERIT Hydro, and a global topography map from MERIT DEM. The results of this model are the conditions and historical data of river discharge, and inundation area on the island of Java. The use of global-scale river models has not yet been widely implemented in Indonesia. Therefore, this research is conducted to understand changes in flooding on an island and will advance climate system studies and assist both non-governmental and governmental institutions in formulating flood mitigation policies for the Java Islands.