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The Plymouth Student Scientist

Document Type

Biological and Marine Sciences Article

Abstract

Coastal infrastructure faces increasing threats from wave overtopping due to climate change, rising sea levels, and intensifying storms. This research investigates the environmental conditions that drive hazardous wave overtopping using Dawlish, a vulnerable section of the UK’s railway, as a case study. Understanding these conditions is essential for improving knowledge, developing effective mitigation strategies, and enhancing the resilience of shoreline defences against future challenges. Using one-year observations from WireWall instruments, offshore wave buoy, and meteorological data, the research applies a Random Forest model to assess the influence of metocean conditions on overtopping. The results indicate that wave height, tidal level, and wave direction are the primary drivers, with wind speed and direction playing a secondary but potentially significant role despite their omission from empirical models like EurOtop. Analysis of events exceeding the railway wall reveals that southerly waves (Hs > 1.5 m) combined with strong south-southwest winds (>10 m/s) are key triggers of extreme overtopping occurrences. High-impact overtopping occurs predominantly when wave periods range from 6 to 7 s, aligning with mid-to-high tidal levels, particularly around 90 minutes before high tide. Comparisons between WireWall field measurements and EurOtop predictions highlight discrepancies, as the empirical model under-represents overtopping severity under certain conditions. The Random Forest model demonstrates sensitivity to input complexity, resulting in some overprediction of overtopping events. The exclusion of nearshore morphological data and the reliance on distant wind measurements introduces uncertainty, highlighting the need to incorporate on-site wind monitoring, beach profile dynamics, and longer-term datasets to improve predictions. These findings underscore the increasing risk of overtopping at coastal locations, such as Dawlish, and emphasise the necessity for improved real-time forecasting and adaptive coastal management strategies. As sea levels rise and storm intensities increase, integrating high-resolution environmental monitoring and advanced modelling techniques will be essential for protecting vital transport networks in vulnerable coastal regions.

Publication Date

2025-12

Publication Title

The Plymouth Student Scientist

Volume

18

Issue

2

ISSN

1754-2383

Deposit Date

2025-12

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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