The Impact of Seawall on Sediment Characteristics and Morphodynamics Along The Northeastern Coastal of Bengkalis Island, Sumatra, Indonesia

Khaira, Annisa Ulfa; Rifardi, Rifardi

doi:10.21608/ejabf.2025.425654.6616

The Impact of Seawall on Sediment Characteristics and Morphodynamics Along The Northeastern Coastal of Bengkalis Island, Sumatra, Indonesia

Document Type : Original Article

Authors

¹ Department of Marine Sciences, Faculty of Fishery and Marine Sciences, Riau University, Pekanbaru, Riau, Indonesia

² Marine Sciences, Faculty of Fishery and Marine Sciences, Riau University, Riau, Indonesia

10.21608/ejabf.2025.425654.6616

Abstract

Understanding the spatial variability of coastal sediment characteristics is important for managing dynamic shorelines, particularly in regions affected by both natural process and human activity. This study was conducted in October 2024 on the northeastern coastal of Bengkalis Island, Riau Province, Indonesia, and aimed to study the impact of seawall construction on coastal sediments and assess the morphodynamics of its coastal area. A survey-based approach was employed in this research, with observation stations selected based on an analysis of two decades of shoreline change data (2004–2024) derived from satellite imagery in the coastal zone of Pambang Pesisir Village. Sediment was collected from three stations, each comprising five sampling points. The sediment analysis revealed a dominance of mud and muddy sand, with grain size fractions ranging from medium sand to fine mud (2.33 Ø – 7.2 Ø). These variations indicate diverse energy conditions along the coastline. The measured current velocity, ranging from 0.29 to 0.36 m/s, along with wave energy levels varying between 0.008 and 0.614 J, were identified as primary factors influencing the sediment dynamics. Sorting analysis classified the sediments as poorly to very poorly sorted, suggesting active transport processes. Additionally, positive skewness values indicate a prevalence of finer particles, while kurtosis values range from very platykurtic to extremely leptokurtic, demonstrating heterogeneity in sediment deposition. Notably, the presence of seawall, specifically sheet piles, significantly altered local hydrodynamic regimes, leading to spatial differences in sediment accumulation. The research provides valuable insights into sediment behavior in coastal areas affected by human activities and offers notable information for sustainable shoreline management and coastal protection strategies in Indonesia.

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