## 1 Introduction  
As one of the crucial ports facilitating the maritime transportation of commodities in the Bengkulu Province, Indonesia, Pulau Baai Port is situated approximately 20 km from the city center of South Bengkulu [1; 2; 3]. This port also plays an instrumental role in supporting oil and gas explorations, with vital pipeline installations tracing its shoreline [4]. Consequently, it is imperative to minimize any disturbances that have the potential to harm the pipeline infrastructure along the Pulau Baai Port coastline. Pulau Baai Port directly faces the Indian Ocean, characterized by intense hydrodynamics and ocean waves, which significantly impact its coastline [5; 6; 7]. These ocean waves are more than mere natural forces; they generate substantial wave energy, resulting in significant sediment transport from the shoreline, often surpassing sediment deposition and causing sediment reduction and loss [8; 9]. This predicament is exacerbated by the constant presence of western and eastern monsoon winds, which introduce siltation and sedimentation, leading to the erosion of local beaches [10; 11; 12]. The sedimentation rate along the coastline of Pulau Baai port reaches staggering proportions, with estimates ranging from 600,000 to 800,000 m\({}^{3}\)/year, while coastal abrasion steadily encroaches at a rate of up to 20 m/year [3; 13; 14; 15; 16]. The most severe siltation occurs at the port's entrance channel, and if left unchecked, it could have severe consequences, including disruptions to economic sectors and the potential exposure of existing pipeline installations along its shoreline [17; 18; 19]. This is due to the main access to the port being hindered by siltation or erosion along the coast [20; 21]. The sediment transport occurring in coastal areas is a crucial physical process leading to erosion and deposition, and this has been the focus of study for several authors employing a modeling approach [22; 23]. Utilizing a comprehensive sediment transport model with a specific focus on the most affected port areas, the MIKE 21 modeling tool was employed to assess the impacts of waves, wind, and tidal surges on the coastal abrasion reality of Pulau Baai Port. The Spectral Wind-Wave Model (SW) and Hydrodynamic Model (HD) modules were utilized [11; 24; 25]. The calibrated and verified MIKE 21/3 FM Coupled Model was then applied to quantify the morphological changes in the shoreline due to sediment transport over the next 10 years. The results of the shoreline morphological changes from the simulated period are used as a reference to formulate effective and efficient alternatives for implementation at the study site. In the planning of appropriate alternatives, MIKE 21 was also used to simulate the effects of waves and tidal floods on currents and erosion dynamics, taking into account the planned construction of alternatives. This modeling was conducted using three different scenarios: a scenario without using alternatives, a scenario using shore protection alternatives, and a scenario using jetty protection alternatives. A comprehensive dataset, including bathymetric maps, wave patterns, current data, and sediment characteristics, was compiled to support this research. These components provide essential elements for a comprehensive analysis of coastal dynamics at Pulau Baai Port, emphasizing the urgent need for proactive interventions. The primary aim of this research was to gain insights that will enable informed decision making when selecting optimal solutions to mitigate dredging challenges. The results of this model-based investigation will serve as a foundation for strategies guiding efforts to ensure the sustainable functionality of maritime infrastructure in the surveyed research area. The novelty of this research lies in the analysis of coastal abrasion evident in Pulau Baai Port, demonstrated by the exposure of underground pipelines to the open air.