ASSESSMENT OF SEABED FEATURES IN THE VICINITY OF KEMAMAN PORT, TERENGGANU, MALAYSIA

Abstract

Sedimentation poses a significant challenge to navigational safety within port areas, including at Kemaman Port, Terengganu, Malaysia. This study characterised seabed morphology and identifies key features, including sediment distribution, submerged objects, and potential hazards that may impact port operations and navigational safety. Side-scan sonar (Klein 3000 dual-frequency system operating at 100 and500 kHz) and Compressed High-intensity Radar Pulse (CHIRP) sub-bottom profiler (EdgeTech Strata Box) were employed to produce detailed seabed maps of the seabed across four survey zones (CN, P, R, CS) encompassing 23 sampling stations with 50 m survey-line spacing with 50 m line spacing. Sediment analyses revealed that the port basin is dominated by silt-clay mixtures (mean D50 = 0.045 mm, 68% mud content), whereas the river mouth was characterised by coarse sand and gravel deposits (mean D50 = 1.2 mm, 12% mud content). Three distinct acoustic facies were identified and showed strong correspondence with sediment grain-size distributions, achieving 87% classification agreement. A total of 37 potential navigational hazards were identified, including five major scour pits adjacent to the breakwater (15 m–45 m in diameter, 2 m–8 m in depth), 18 submerged objects, and four active bedform fields. High-energy bedforms, with ripple wavelengths ranging from 0.8 m to 1.5 m were observed in the navigation channels, indicating active sediment transport processes. CHIRP sub-bottom profiler data revealed three stratigraphic units with surficial sediment accumulation reaching 1.8 m in the port basin, corresponding to a sedimentation rate of approximately 7 cm per year since port construction. The findings provide quantitative baseline data to provide quantitative baseline information to support port management, assist with marine safety initiatives, and inform future dredging strategies and coastal monitoring programmes in the region.