Title
Critical turbidity thresholds for maintenance of estuarine tidal flats worldwide
Author
Grandjean, Tim J. (NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)
Weenink, Roland (NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)
van der Wal, Daphne (NIOZ Royal Netherlands Institute for Sea Research; University of Twente)
Addink, Elisabeth A. (Universiteit Utrecht)
Hu, Zhan (Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering; Sun Yat-sen University; Ministry of Education, Zhuhai; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai))
Liu, Shuai (Sun Yat-sen University; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai))
Wang, Zhengbing (TU Delft Coastal Engineering; Deltares) 
Lin, Yuan (Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station; East China Normal University)
Bouma, Tjeerd J. (NIOZ Royal Netherlands Institute for Sea Research; Universiteit Utrecht)
Date
2024
Abstract
Tidal flats are shrinking in extent globally. The dynamics of the response of estuarine tidal flats to global environmental changes remain unclear. Tidal-flat morphology is shaped by the interplay among wave and tidal forces, river discharge and sediment supply, and preservation of tidal flats requires a balance between erosional and depositional processes be maintained. Here we assess tidal-flat morphodynamic changes of 40 globally distributed estuaries with contrasting tidal amplitudes between 1986 and 2011 from analyses of 4,939 satellite images. We consider both vegetated and unvegetated intertidal areas. From comparisons with remote-sensing-derived turbidity estimates, we identify a critical turbidity threshold indicative of a minimum sediment supply along with the hydrodynamic forces, which is necessary to maintain tidal flats. Tidal flats in intertidal areas in estuaries with low turbidity face retreat, with the critical turbidity threshold increasing with increasing tidal amplitudes. By contrast, estuaries with high turbidity tend to exhibit laterally or vertically expanding tidal flats. However, despite estuaries with limited tidal ranges having relatively low turbidity thresholds, environmental or anthropogenic alterations can still adversely affect the morphology of tidal flats. Our findings demonstrate the need to consider sediment supply in integrated estuarine management strategies to maintain the ecological integrity and flood defence function of tidal flats.
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http://resolver.tudelft.nl/uuid:8634fe94-8d58-49b3-951e-98c890c3db09
DOI
https://doi.org/10.1038/s41561-024-01431-3
Embargo date
2024-11-06
ISSN
1752-0894
Source
Nature Geoscience
Bibliographical note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2024 Tim J. Grandjean, Roland Weenink, Daphne van der Wal, Elisabeth A. Addink, Zhan Hu, Shuai Liu, Zhengbing Wang, Yuan Lin, Tjeerd J. Bouma