Exploring distinct types of intertidal bars on either side of a small estuary using a multifaceted approach
Multiple intertidal bars are common sedimentary landforms found on low-gradient sandy coasts exposed to low to moderate wave energy with a significant tidal range. However, studying the factors that influence their morphology can be challenging due to limited high-resolution field data and tools for...
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Veröffentlicht in: | Marine geology 2023-07, Vol.461, p.107078, Article 107078 |
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Zusammenfassung: | Multiple intertidal bars are common sedimentary landforms found on low-gradient sandy coasts exposed to low to moderate wave energy with a significant tidal range. However, studying the factors that influence their morphology can be challenging due to limited high-resolution field data and tools for bedform analysis. To address this, a multifaceted approach was used to investigate the morphology of intertidal bars at two adjacent tidal beaches on the north and south coasts of a small estuary on the Lianyungang coast of China. This approach included repeated real-time kinematic-global positioning system (RTK-GPS) leveling, unmanned aerial vehicle (UAV) surveys, surface sediment sampling, satellite remote sensing analysis, and automated bedform analysis. The study revealed two distinct types of intertidal bars on either side of the estuary with similar hydrodynamic settings. The north coast presented low-amplitude ridges (also called ridges and runnels), while the south coast had sand waves. The north coast displayed 2–5 oblique, asymmetrical, and dynamic bars that appeared at the seaward end of the intertidal zone and migrated landward to eventually attach to the steep beach on the landward end of the intertidal zone, representing a life cycle. The south coast had 6–9 parallel, continuous, symmetrical, and stable sand bars occupying the lower part of the intertidal zone. Due to the nearly identical hydrodynamic background, the alongshore variability in sediment supply is suggested as a key factor driving the formation of distinct types of bars.
•Two types of intertidal sand bars were revealed on either side of a small estuary.•Oblique and asymmetrical low-amplitude ridges migrate landward on the north coast.•Symmetrical and stable sand waves occupy lower intertidal flat of the south coast.•Sediment supply is a key factor in the formation of these two types of sand bars.•UAV surveys expand the space and remote sensing extends the time of measurements. |
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ISSN: | 0025-3227 1872-6151 |
DOI: | 10.1016/j.margeo.2023.107078 |