Morphodynamics of a bedrock confined estuary and delta: The Skeena River Estuary

Date

2020-12-07

Authors

Wild, Amanda Lily

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Abstract

Bedrock islands add variation to the estuarine system that results in deviations from typical unconfined estuarine sediment transport patterns. Limited literature exists regarding the dynamics of seabed morphology, delta formation, sediment divergence patterns, and sedimentary facies classifications of non-fjordic bedrock confined systems. Such knowledge is critical to address coastal management concerns adequately. This research presents insights from the Skeena Estuary, a macrotidal estuary in northwestern Canada with a high fluvial sediment input (21.2-25.5 Mtyr-1). Descriptions on sub-environments, stratification, and sediment accumulation within the Skeena Estuary utilize HydroTrend model outputs of riverine sediment and discharge, Natural Resources Canada radiocarbon-dated sediment cores and grain size samples, and acoustic Doppler current profiler and conductivity-temperature-depth measurements from three field campaigns. Research findings delineate a fragmented delta structure with elongated mudflats and select areas of slope instability. Variations from well-mixed water circulation to lateral stratification, govern the slack tide flow transition and sediment transport pathways within seaward and landward passages of the estuary. Fostering a comprehensive understanding of bedrock confined estuary and delta systems has implications for the assessment of coastal management strategies, the productivity of ecological habitats, and the impacts of climate change within coastal areas.

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Keywords

Estuary, Skeena, Geomorphology, Oceanography, Morphodynamics, Delta, ADCP, Stratification, Bedrock, Suspended Sediment, Watershed, Discharge, Macrotidal, Fjard, Chronostratigraphy, HydroTrend, Sediment Core, Bathymetry, Grain size distribution, Sedimentation, Partially Mixed Estuary, Bedrock Confined Estuary, River, Rivers of British Columbia, Radiocarbon Dating of Sediments, Ebb Tide, Flood Tide, Slack Tide

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