Collision Risk Analysis and Oil Spill Dispersion Modelling in Lombok Strait

Abstract

Lombok Strait is one of the water areas that designated for international shipping lanes since it has been adopted as the Indonesia Archipelagic Sea lane (IASL) II in 1998. Foreign-flagged ships passing through the strait from southbound to northbound and vice versa. Along with being an archipelagic sea lane, the strait also occupied by high-density crossing traffic connecting Bali and Lombok islands. This crossing traffic mainly dominated by passenger ferry Ro-Ro and pleasure ships as both Bali and Lombok islands are well known as tourist destinations. Aside from being a tourist destination, several islands around the Lombok Strait are also dedicated to Marine Protected Areas (MPA). There are two areas designated for MPA by the Indonesian government in the vicinity of Lombok Strait; Nusa Penida on the west side of IASL II and Gili Matra on the east side. The traffic condition allows the potential for collisions on ships passing through and crossing the Lombok Strait which is very likely caused by navigation errors, human errors, weather conditions, and other technical problems. This study aims to determine the collision risk analysis in terms of annual frequency of collision and grounding as well as the potential dispersion of oil that occurs in the event of a ship collision near the MPA of Nusa Penida. Based on one-year traffic data and forecasted to 20 years, collision and grounding frequencies analysis was conducted using iWRAP method. The analysis found that annual frequency including head-on, overtaking, crossing, merging, bend, and grounding is 4.73×10-1. In addition to the frequency of collisions, oil spill dispersion simulations were carried out using GNOME under two different conditions wind and sea current directions; wind and sea currents that heading to the Northwest, and Southwest. Given a scenario of collision occurred close to Nusa Penida island involving tanker ship that resulting hull damage and oil spill while the wind and sea current directed to Southwest, simulation resulting that oil spill will disperse and polluting MPA of Nusa Penida.