Integrating GIS and ABM for overland flow model in Central Celebes, Indonesia

Overland flows have been worldwide known as an agent of erosion and its spatial distribution has become an object of Terrain Analysis in geographical studies. They would generate debris flows in mountainous areas and lahars in volcanic areas which provoke casualties, economic damage and environmental disturbance as well. The objective of this research is to identify the spatial distribution of river response to excessive overland flow on a confined channel. This study was conducted in northwestern part of Katopasa Mountain in Central Celebes, Indonesia. A massive debris flow had been initiated along the unvegetated area near the summit (2 427 m asl), shut down the national route 20 km downstream before hitting the shoreline next to it. Geographic Information System (GIS) and Agent Based Model (ABM) was integrated in order to develop overland flow model. The result showed that raindrops which acted as agent were moving downslope indicating overland flow mechanism within the catchment area. This flow was spatially directed by local slope orientation into a deep confined channel. The accumulation of agents in this channel formed an increased river discharge and flooding area at the outlet of the catchment. This findings would be useful for supporting mitigation strategies. © 2020 IEEE.