Navigation Safety Risk Assessment and Identification of Black Spot Conflict Areas in the Historic Area of Siak City

Abstract

The increasing intensity of navigation activity on the Siak River, particularly within the Historic Area of Siak City, raises the potential for navigation accidents that may threaten both maritime safety and the preservation of cultural heritage infrastructure along the riverbank. The narrow channel, sharp bends, limited visibility (blind spots), and high vessel traffic are the main factors behind the emergence of navigation conflict areas (black spots). This study aims to identify the location of conflict areas and navigation hazard factors, and to assess the safety risk level at each hazard point using a Risk Matrix. A mixed-method approach was applied using the Hazard Identification and Risk Assessment stages of the HIRARC method, through field observation, expert judgment interviews, and risk matrix analysis based on the AS/NZS 4360:2004 standard. The results show that the bend segment of the Siak River was established as the primary navigation conflict point, based on the convergence of field observation, expert consensus, historical incident records, and hydrodynamic justification. Six main hazards were identified: limited visibility, an overly sharp bend radius, channel narrowing, stronger currents on the outer side of the bend, tidal-induced current changes, and excessive vessel speed. The limited-visibility parameter obtained the highest risk score of 15, categorized as Extreme Risk, indicating the need for priority attention in navigation safety management in the historic area