Flooding Management with System Dynamic Approach (Case Study: Citarik Sub Watershed)

Abstract

Citarik Sub Watershed (Upper Citarum Watershed) is a critical and priority sub watershed indicated by the occurrence of hydrological degradation, the annual flood phenomenon. Floods occur due to runoff increase, influenced by natural and many anthropogenical factors. A necessary study is conducted to model the dynamic system using STELLA related to floods in Citarik Sub Watershed to study the flood phenomenon, its influential components, and their interactions by simulated scenario and become a consideration in determining policies based on the flood discharge. The model shows based on the sensitivity analysis that the low leverage variables include growth and mortality rate, while the high leverage variables include forest conversion rate. According to the case analysis, the RPJMN (26 m³/s) and river normalization (16.82 m³/s) policies are considered to be enhanced with other scenario and the most effective scenario based on STELLA running result by maintaining a minimum forest area of 30% of the watershed's total area and reducing the forest conversion rate to zero by making the forest a conservation forest and conducting reforestation, the model predicted that this scenario could avoid flooding occurred (0 m³/s) in the area for the next 20 years.