Impact of intertidal habitats on hydrodynamics in tidally energetic, well-mixed estuaries

Zhu, Renjie; Zhang, Wei; Wei, Xiaoyan ORCID: https://orcid.org/0000-0001-8407-6958. 2025 Impact of intertidal habitats on hydrodynamics in tidally energetic, well-mixed estuaries. Journal of Physical Oceanography. 10.1175/JPO-D-23-0172.1

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Official URL: https://doi.org/10.1175/JPO-D-23-0172.1

Abstract/Summary

Estuarine intertidal habitats, which strongly affect the functioning of estuarine ecosystems, have rapidly diminished worldwide due to human activities and climate change. However, the mechanisms by which intertidal habitats modulate estuarine hydrodynamics remain poorly understood. A three-dimensional semi-analytical model is developed to systematically investigate the interactions between intertidal and channel waters in tidally dominated, well-mixed estuaries. By considering simplified bathymetry, geometry, and forcing conditions, the model dynamically couples intertidal and channel water motions using a perturbation method that allows for an explicit dissection of different controlling physical processes. Our findings reveal that intertidal habitats amplify semi-diurnal tidal motions, causing significantly enhanced residual and quarter-diurnal tidal currents due to advection (AC). The strengthened AC shifts the pattern and magnitude of the total residual circulation. Lateral water exchange between intertidal and channel regions generates a new residual and quarter-diurnal tidal contribution (TF), which dampens quarter-diurnal tidal currents in the deep channel. The TF and enhanced AC due to intertidal habitats increase ebb-dominance in the deep channel. Our sensitivity analysis shows that halving the intertidal width halves the water exchange and the above-mentioned intertidal effects on the residual and tidal currents, and the upper-estuary habitats induce broader changes in the channel hydrodynamics than lower-estuary habitats. We also found that increasing estuary length/convergence strongly affects the intertidal effects. These findings highlight the importance of understanding interactions between intertidal and channel waters to evaluate the risks of intertidal habitat loss for estuarine functioning and the potential benefits of intertidal habitat restoration/creation in mitigating estuarine hazards.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1175/JPO-D-23-0172.1
ISSN:	0022-3670
Date made live:	03 Jul 2025 21:53 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/539782

Item Type:

Publication - Article

Digital Object Identifier (DOI):

10.1175/JPO-D-23-0172.1

ISSN:

0022-3670

Date made live:

03 Jul 2025 21:53 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/539782