A measurement-to-modelling approach to understand catchment-to-reef processes: sediment transport in a highly turbid estuary

• DOI: 10.3389/fmars.2023.1215161
• Publication Date: 2023-10-18T09:20:18Z
• Authors: Ziyu Xiao; Geoffrey Carlin; Andrew D. L. Steven; Daniel N. Livsey; Dehai Song; Joseph R. Crosswell
• Keywords: Discharge; Biogeochemical Cycle; Turbidity

As sediments carried by rivers enter coastal waters, fine particles can reduce the amount of light that reaches reef through attenuation. The Fitzroy Estuary - Keppel Bay (FE-KB), being second-largest source to Great Barrier Reef (GBR) poses a significant threat GBR ecosystem such as coral reefs and seagrass meadows, biogeochemical cycles influence water clarity. While monitoring modelling capabilities for catchment marine settings are now well-developed operational, remaining key gap is better understand model transport, dynamics fate derived material tidally influenced sections discharge into GBR. This study aims reveal sediment transport in FE-KB estuary continuously seasonal variability over year-long period build high-resolution predict budgets under different scenarios physical forcing river conditions. Multiple data sources, including field surveys, historical data, numerical were used obtain detailed understanding processes during wet (high flow) dry (low-to-no seasons. use bathymetry survey parameterization allowed accurate mapping morphological changes, while modeling provided insights hydrodynamic estuary. Observation confirm existence Turbidity Maximum Zone (TMZ) (approximately 35 – 40 km from head), where topography plays critical role trapping sediments. By utilizing model, closed budget was calculated varying flow conditions results determine estuarine coefficient ranges 28% (during extreme condition) 100% total loads. Morphodynamic demonstrated persistent erosion pattern upper reach FE. lower FE southern tidal creeks serve large storage basin both seasons, exported deposited offshore high