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Increased coastal wave hazard generated by differential wind and wave direction in hyper-tidal estuaries.

Authors :
Lyddon, Charlotte E.
Brown, Jennifer M.
Leonardi, Nicoletta
Plater, Andrew J.
Source :
Estuarine Coastal & Shelf Science. May2019, Vol. 220, p131-141. 11p.
Publication Year :
2019

Abstract

Abstract Wave overtopping and subsequent coastal flood hazard is strongly controlled by wind and water levels, and is especially critical in hyper-tidal estuaries where even small changes in wave heights can be catastrophic if they are concurrent with high spring tide. Wave hazard in estuaries is largely attributed to high amplitude shorter period, locally generated wind waves; while low amplitude longer period waves rarely impact low-lying coastal zones up-estuary. Here, the effect of wind and wave properties on up-estuary wave propagation and the sensitivity of significant wave height are investigated numerically along the shoreline of the Severn Estuary, southwest England, as an example. Representative values for wind speed and direction, wave height, period and direction are used to identify key combinations of factors that define the wave hazard generation. High amplitude, short period wind waves are sensitive to opposing winds, with a steepening effect that varies along the estuary shoreline, highlighting the effect of estuarine geometry on wave hazard. Low amplitude, long period wind waves respond with maximum variability in significant wave height to strong winds resulting in their propagation further up-estuary. Our results advance current understanding of the compound interaction between wind and waves, and identify critical conditions maximizing the hazard and hazard variability along the shoreline. The outcomes from this research can help to avoid economic losses from operational downtime in ports and harbors, inform sustainable coastal sea defense design and understand how wave hazard may vary under future climate due to changing storm tracks. Results can also be applied to the design of coastal infrastructure and facilitation of emergency response planning. Highlights • Key combinations of wind wave factors simulated to define wave hazard. • Opposing winds steepen high amplitude waves to increase overtopping hazard. • Stronger winds amplify low amplitude waves and facilitate propagation up-estuary. • Results can inform sea defense design and reduce losses from operational downtime. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
02727714
Volume :
220
Database :
Academic Search Index
Journal :
Estuarine Coastal & Shelf Science
Publication Type :
Academic Journal
Accession number :
135625534
Full Text :
https://doi.org/10.1016/j.ecss.2019.02.042