Historic Spatial Patterns of Storm-Driven Compound Events in UK Estuaries
Lyddon, C.; Robins, P.; Lewis, M.; Barkwith, A.; Vasilopoulos, G.; Haigh, I.; Coulthard, T.
Dr Grigorios Vasilopoulos G.Vasilopoulos@hull.ac.uk
Postdoctoral Research Associate
Professor Thomas Coulthard T.Coulthard@hull.ac.uk
Professor of Physical Geography
Compound estuarine flooding is driven by extreme sea-levels and river discharge occurring concurrently, or in close succession, and threatens low-lying coastal regions worldwide. We hypothesise that these drivers of flooding rarely occur independently and co-operate at sub-daily timescales. This research aimed to identify regions and individual estuaries within Britain susceptible to storm-driven compound events, using 27 tide gauges linked to 126 river gauges covering a 30-year record. Five methods were evaluated, based on daily mean, daily maximum, and instantaneous 15-min discharge data to identify extremes in the river records, with corresponding skew surges identified within a ‘storm window’ based on average hydrograph duration. The durations, relative timings, and overlap of these extreme events were also calculated. Dependence between extreme skew surge and river discharge in Britain displayed a clear east–west split, with gauges on the west coast showing stronger correlations up to 0.33. Interpreting dependence based on correlation alone can be misleading and should be considered alongside number of historic extreme events. The analyses identified 46 gauges, notably the Rivers Lune and Orchy, where there has been the greatest chance and most occurrences of river-sea extremes coinciding, and where these events readily overlapped one another. Our results were sensitive to the analysis method used. Most notably, daily mean discharge underestimated peaks in the record and did not accurately capture likelihood of compound events in 68% of estuaries. This has implications for future flood risk in Britain, whereby studies should capture sub-daily timescale and concurrent sea-fluvial climatology to support long-term flood management plans.
Lyddon, C., Robins, P., Lewis, M., Barkwith, A., Vasilopoulos, G., Haigh, I., & Coulthard, T. (in press). Historic Spatial Patterns of Storm-Driven Compound Events in UK Estuaries. Estuaries and coasts : journal of the Estuarine Research Federation, https://doi.org/10.1007/s12237-022-01115-4
|Journal Article Type||Article|
|Acceptance Date||Jul 26, 2022|
|Online Publication Date||Aug 31, 2022|
|Deposit Date||Oct 4, 2022|
|Publicly Available Date||Oct 27, 2022|
|Journal||Estuaries and Coasts|
|Peer Reviewed||Peer Reviewed|
|Keywords||Coast; Estuary; Combination hazard; Compound flooding; Flood risk|
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© The Author(s) 2022.<br /> Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
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