Developing numerical model of debris flow 2D as a tool in Early Warning System

The occurrences of debris flow in volcanic mountainous or non-volcanic mountainous areas often cause disaster in surrounding rivers, so it had raised loss of lives and properties. In order to reduce the loss of lives due to the debris flow, it needs to develop an early warning system. To predict the threatened area along the river valley by debris flow could be forecasted using a numerical model. Therefore, it is required to develop a numerical model of debris flow as a tool for forecasting the threatened area in an early warning system. Developing the numerical model of flow of debris flow was based on the two equations, namely, the flow and sediment equations. Both of these equations were discreted using finite difference method. The FORTRAN language was used to write source code program. To test the performance u[the numerical model, three cases of debris flow in were carried in Putih River, Jember, East Java, Indonesia. The simulations were performed with 3 (three) scenarios. The first scenario was run with input discharge equal to the estimated results of hydrographs flood event of 2006. The second scenario and the third scenario were run with input discharge of 0.7 and 1.5 of estimated flood of 2006, respectively. The simulation results showed that the developed numerical model was capable to simulate the flood-affected areas. However, if the simulation results were compared with the affected area due to the debris flow of 2006, it shows that some areas are not appropriate. This condition is caused by the digital elevation map (OEM) was used as input simulation could not describe the real conditions perfectly