Uncertainty in estuarine extreme water level predictions due to surge-tide interaction.

Lyddon, Charlotte ORCID: 0000-0003-4254-3049, Brown, Jenny M, Leonardi, Nicoletta and Plater, Andrew J ORCID: 0000-0001-7043-227X (2018) Uncertainty in estuarine extreme water level predictions due to surge-tide interaction. PloS one, 13 (10). e0206200-e0206200.

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Abstract

Storm surge is often the greatest threat to life and critical infrastructures during hurricanes and violent storms. Millions of people living in low-lying coastal zones and critical infrastructure within this zone rely on accurate storm surge forecast for disaster prevention and flood hazard mitigation. However, variability in residual sea level up-estuary, defined here as observed sea level minus predicted tide, can enhance total water levels; variability in the surge thus needs to be captured accurately to reduce uncertainty in site specific hazard assessment. Delft3D-FLOW is used to investigate surge variability, and the influence of storm surge timing on barotropic tide-surge propagation in a tide-dominant estuary using the Severn Estuary, south-west England, as an example. Model results show maximum surge elevation increases exponentially up-estuary and, for a range of surge timings consistently occurs on the flood tide. In the Severn Estuary, over a distance of 40 km from the most upstream tide gauge at Oldbury, the maximum surge elevation increases by 255%. Up-estuary locations experience short duration, high magnitude surge elevations and greater variability due to shallow-water effects and channel convergence. The results show that surge predictions from forecasting systems at tide gauge locations could under-predict the magnitude and duration of surge contribution to up-estuary water levels. Due to the large tidal range and dynamic nature of hyper-tidal estuaries, local forecasting systems should consider changes in surge elevation and shape with distance up-estuary from nearby tide gauge sites to minimize uncertainties in flood hazard assessment.

Item Type:	Article
Uncontrolled Keywords:	Humans, Uncertainty, Disasters, Environmental Monitoring, Oceanography, Models, Theoretical, Forecasting, Floods, Tidal Waves, Cyclonic Storms, Hydrodynamics, Estuaries, United Kingdom
Depositing User:	Symplectic Admin
Date Deposited:	05 Nov 2018 11:48
Last Modified:	19 Jan 2023 01:13
DOI:	10.1371/journal.pone.0206200
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3028399