Overtopping Damage Classification

Overtopping Damage Classification

Source: CHESS_Library/Structure_Reponses/Equations/get_overtopping_damage.m, with the thresholds also tabulated in CEM_table_VI-5-6.csv in the same folder. Applies to: any overtopping rate q, from any structure type. Enable flag: none. A standalone utility: it is not called by the response pipeline; call it on any q result.

What it models

A mean overtopping rate on its own does not say whether it matters. This utility translates q into the hazard it poses to six kinds of receptor (vehicles, pedestrians, buildings and three structure types), using the critical overtopping limits of the Coastal Engineering Manual, Table VI-5-6.

Conceptual model

• Each receptor has fixed q thresholds. The class is the band q falls in (lower limit inclusive).
• The thresholds are for the mean overtopping rate. Individual wave volumes can be far larger, so a "safe" class is not a guarantee.
• Applied to a hazard curve value of q, the result reads as "at this annual exceedance probability, overtopping is ... for pedestrians".

Usage

damage_table = get_overtopping_damage(q);                 % q in m^3/s per m (library units)
damage_table = get_overtopping_damage(q, 'l/s per m');    % q in l/s per m

Returns one table row per q value with the columns Discharge, Units, Vehicles, Pedestrians, Buildings, Embankment_Seawalls, Grass_Sea_Dikes, Revetments.

Thresholds (m³/s per m)

Receptor	Class	q range
Vehicles	Safe driving at all speeds	< 1e-6
	Unsafe driving at high speed	1e-6 – 1e-5
	Unsafe parking on vertical wall breakwaters	1e-5 – 3e-5
	Unsafe parking on horizontal composite breakwaters	3e-5 – 1e-4
	Unsafe at any speed	≥ 1e-4
Pedestrians	Wet, but not uncomfortable	< 3e-5
	Uncomfortable but not dangerous	3e-5 – 1e-4
	Dangerous on vertical wall breakwaters, grass sea dikes and horizontal composite breakwaters	1e-4 – 1e-3
	Very dangerous	≥ 1e-3
Buildings	No damage	< 1e-6
	Minor damage to fittings, sign posts, etc.	1e-6 – 1e-3
	Structural damage	≥ 1e-3
Embankment seawalls	No damage	< 2e-5
	Damage if crest not protected	2e-5 – 2e-3
	Damage if back slope not protected	2e-3 – 2e-2
	Damage even if fully protected	≥ 2e-2
Grass sea dikes	No damage	< 1e-3
	Start of damage	1e-3 – 1e-2
	Damage	≥ 1e-2
Revetments	No damage	< 5e-2
	Damage if promenade not paved	5e-2 – 2e-1
	Damage even for paved promenade	≥ 2e-1

Related

• EurOtop Overtopping Discharge q: how q is computed.

References

• U.S. Army Corps of Engineers. Coastal Engineering Manual, EM 1110-2-1100, Part VI, Table VI-5-6 (critical values of average overtopping discharges).