Hydrological Network Analysis Using Graph Theory Through Literature Study: The Dominant Effect Of Deforestation On Changes In Discharge And Flood Risk In Indonesian River Basins

Abstract

This study aims to identify and analyze the impact of deforestation on hydrological changes and its relationship to increased flood risk in Indonesian watersheds through a descriptive-analytical literature review. The high rate of deforestation due to logging, land conversion (such as food estates), and development has disrupted the function of forests as a balancing agent in the hydrological system, which is characterized by a significant increase in surface runoff and extreme river flow fluctuations. The research method uses systematic literature studies and secondary data analysis from scientific publications from 2015 to 2025. The data were analyzed using a descriptive-analytical qualitative approach, combined with Graph Theory Analysis to map the relationships between environmental and hydrological variables. The results of the network centrality analysis showed that Deforestation and River Discharge were the most dominant nodes (Degree S= 6 S; Betweenness Centrality S> 0.42S). Deforestation was found to have a strong positive relationship with Surface Runoff (weight 0.85) and a negative relationship with Soil Infiltration (weight 0.78). This confirms that the systematic loss of vegetation reduces the soil's ability to retain water, accelerates surface runoff, and increases River Peak Discharge, which ultimately exacerbates the risk of flooding. The Erosion variable occupies the position as the final consequence (terminal response) with the lowest centrality value.