Assessment of land reclamation effects on material transport in the Bohai Bay based on information entropy theory

Abstract

This study quantitatively assesses the impact of large-scale land reclamation on material transport dynamics in Bohai Bay, China. We developed a hydrodynamic model using the Finite-Volume Community Ocean Model (FVCOM), incorporating both tidal currents and wind-tide coupling, alongside Lagrangian particle tracking. The novel application of information entropy theory within Lagrangian Flow Networks (LFNs) enabled the characterization of material transport patterns. Specifically, input entropy was used to measure material aggregation, while output entropy characterized diffusion capacity. Results revealed distinct seasonal variations in transport patterns driven by wind fields: “north aggregation and south dispersion” in summer contrasting with “south aggregation and north dispersion” in winter. After land reclamation, the input entropy near Caofeidian Port increased by approximately 160 %, indicating a more concentrated material aggregation pattern, and the output entropy near Tianjin Port decreased by about 167 %, suggesting a reduced diffusion capacity. These areas exhibited marked changes in input and output entropy values after reclamation, indicating increased uncertainty in both the aggregation and diffusion of materials. This research demonstrates that information entropy within LFNs provides an effective quantitative framework for evaluating the ecological impacts of coastal engineering projects. The findings offer critical insights for marine environmental management and sustainable coastal development planning.