Abstract:
Beaches combined with sloping structures are frequently the frst element of defense to protect
urban areas from the impact of extreme coastal fooding events. However, these structures are rarely
designed for null wave overtopping discharges, accepting that waves can pass above the crest and
threat exposed elements in hinterland areas, such as pedestrians, urban elements and buildings,
and vehicles. To reduce risks, Early Warning Systems (EWSs) can be used to anticipate and minimize
the impacts of fooding episodes on those elements. A key aspect of these systems is the defnition
of non-admissible discharge levels that trigger signifcant impacts. However, large discrepancies in
defning these discharge levels and the associated impacts are found among the existing methods
to assess foodings. Due to the lack of standardization, a new conceptual and quantitative four-level
(from no-impact to high-impact) categorization of food warnings (EW-Coast) is proposed. EW-Coast
integrates and unifes previous methods and builds on them by incorporating feld-based information.
Thus, the new categorization successfully predicted the impact level on 70%, 82%, and 85% of the
overtopping episodes afecting pedestrians, urban elements and buildings, and vehicles, respectively.
This demonstrates its suitability to support EWSs in areas vulnerable to wave-induced fooding.
