A Framework for Modeling Sediment Transport Dynamics in Coastal Environments

Thesis Abstract

Coastal sediment transport plays a critical role in shaping shoreline morphology, influencing ecological habitats, and impacting coastal management practices amidst the increasing pressures of climate change and human development. Despite substantial advancements, current models often lack an integrated framework that accommodates the complex interactions among hydrodynamic forces, sediment characteristics, and topographical variability. This study aims to develop a comprehensive modeling framework that accurately depicts sediment transport dynamics in diverse coastal environments, improving predictive capabilities for sustainable coastal management. The specific objectives include (1) to identify key factors influencing sediment transport processes through literature synthesis and field data; (2) to establish a conceptual model linking hydrodynamic parameters, sediment properties, and coastal morphology; and (3) to formulate and validate a computational framework utilizing statistical and numerical techniques. The research adopts a mixed-methods approach, combining qualitative theoretical development with quantitative model validation. The study population encompasses three representative coastal sites with contrasting sediment compositions—namely, sandy, silty, and mixed sediment regimes—each with a minimum of 30 measurement stations systematically distributed across selected transects. Data collection involves deploying Acoustic Doppler Current Profilers (ADCPs), sediment grab samplers, and wave buoys over a 12-month period to record flow velocities, wave heights, sediment grain sizes, and sediment concentrations at hourly intervals. Additional topographical surveys employ Light Detection and Ranging (LiDAR) technology to capture shoreline changes. Validity and reliability of instruments are ensured through calibration procedures aligned with International Standards. Data analysis utilizes a combination of multivariate regression analysis to determine relationships among variables, Principal Component Analysis (PCA) to identify dominant factors, and numerical simulations grounded in the sediment transport equations derived from the Exner equation and the Bagnold shear stress concepts within the framework of the Longshore Sediment Transport Model and the Smoothed Particle Hydrodynamics (SPH) method. A hierarchical modeling approach integrates these components into a unified computational framework. Expected findings indicate that sediment transport is predominantly governed by a synergy of wave-induced shear stress, current velocity, sediment grain size, and coastline morphology, with site-specific nuances. The study anticipates demonstrating that the proposed framework enhances predictive accuracy over existing models by explicitly incorporating complex feedback mechanisms such as sediment feedback effects and temporal variability. It is expected to yield a versatile tool for coastal engineers and hydrologists, capable of simulating sediment fluxes under varying climatic and anthropogenic scenarios. The contribution of this research primarily lies in filling critical gaps identified in the literature regarding the integration of hydrodynamic and sedimentological parameters within a unified modeling context. By advancing a theoretically sound, empirically validated framework, the study offers a pragmatic basis for coastal risk assessments and decision-making strategies. It also extends existing theories by operationalizing them within a flexible and scalable computational platform, fostering transferable applications across different geographic and geomorphological settings. The main conclusion underscores the importance of adopting an integrated, dynamics-based modeling approach to improve foresight in sediment management and shoreline stabilization efforts. Recommendations include the adoption of the framework in coastal planning processes, further refinement through real-time data assimilation, and the expansion of the model to incorporate ecological interactions and sediment chemistry. Future research should explore the adaptation of this framework to understand sediment transport under extreme weather events and to assess long-term morphological evolution, thereby contributing toward more resilient coastal communities.