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

Autor: Lyddon C; Department of Geography and Planning, University of Liverpool, Liverpool, United Kingdom.; National Oceanography Centre Liverpool, Joseph Proudman Building, Liverpool, Merseyside, United Kingdom., Brown JM; National Oceanography Centre Liverpool, Joseph Proudman Building, Liverpool, Merseyside, United Kingdom., Leonardi N; Department of Geography and Planning, University of Liverpool, Liverpool, United Kingdom., Plater AJ; Department of Geography and Planning, University of Liverpool, Liverpool, United Kingdom.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2018 Oct 26; Vol. 13 (10), pp. e0206200. Date of Electronic Publication: 2018 Oct 26 (Print Publication: 2018).
DOI: 10.1371/journal.pone.0206200
Abstrakt: 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.
Competing Interests: The authors have declared that no competing interests exist.
Databáze: MEDLINE
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