Spatiotemporal variability of Total Suspended Sediment (TSS) in the Banda Aceh coastal zone, Indonesia, and its environmental implications

Abstract Understanding the variability of Total Suspended Sediment (TSS) is essential for managing sediment-related pollution in estuarine and coastal environments. This study aimed to analyze the spatial and temporal variability of TSS along the Banda Aceh coast, Indonesia, and its extended impacts on the surrounding environment using an integrated approach that combines satellite remote sensing, hydrodynamic modeling, and multivariate statistical analysis. Satellite-derived TSS concentrations were estimated from Sentinel 2A imagery using empirical algorithms, with the green/blue band ratio (B3/B2) performing best (R 2 = 0.47, RMSE = 21.73 mg/L) against in-situ observations. Hydrodynamic simulations conducted using MIKE 21 revealed marked spatial and temporal variability in TSS distribution driven by tidal conditions and estuarine morphology. During spring tides, stronger currents (up to 0.45 m/s) facilitated widespread TSS dispersal offshore, with concentrations exceeding 250 mg/L in Ulee Lheue and Alue Naga Estuary. In contrast, neap tides resulted in slower current speeds (< 0.20 m/s) and higher TSS retention near the river mouths. The Krueng Aceh Estuary exhibited more stable and lower TSS concentrations (< 181 mg/L) because of its open configuration and reduced sediment trapping. Principal Component Analysis showed that the TSS was positively correlated with turbidity and chlorophyll-a, underscoring its role in controlling water clarity and nutrient dynamics. These findings demonstrate the dominant influence of tidal dynamics, anthropogenic contributions, and riverine discharge on the coastal water quality. The combined remote sensing–modeling framework offers a scalable approach for sediment monitoring and management in other vulnerable, urbanizing coastal systems.