EurOtop Wave Runup & Overtopping Master – Complete Guide + Free Calculator

EurOtop Wave Runup & Overtopping Master

Complete guide to coastal structure design – EurOtop 2018, Van der Meer, Hunt methods

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🌊 Why Wave Runup & Overtopping Matter

Wave runup is the vertical height waves reach on a slope above still water level. Overtopping is the volume of water that passes over the crest. These are critical for designing seawalls, dikes, breakwaters, and revetments. Failure to predict them accurately leads to flooding, erosion, and structural collapse. This calculator follows the EurOtop 2018 manual, the gold standard for coastal engineering.

📐 Key Formulas Integration:
• Runup Equation: Ru_2% = H_s · (1.65 · ξ_m) · γ_combined
• Overtopping (Breaking condition): q = 0.09 · √(g · H_s³) · exp[–(1.5 · R_c / (H_s · γ · ξ_m))^1.3]
• Overtopping (Non-Breaking profile): q = 0.047 · √(g · H_s³) · exp[–(2.6 · R_c / (H_s · γ))^1.3]
• Composite Reduction Factors Index: γ = γ_f · γ_β · γ_b · γ_v

📘 Step‑by‑Step User Guide

1. Input wave conditions: significant wave height (H_s0), peak period (T_p), water depth at the structure toe.
2. Define structure geometry: slope angle (degrees), crest freeboard (R_c).
3. Select reduction factors: roughness (riprap, concrete, etc.), oblique wave angle, berm presence, and vertical wall effect.
4. Choose output unit: metric (m, l/s/m) or imperial (ft, cfs/ft).
5. Click “Compute Analysis Matrix” – the tool calculates runup and overtopping using three methods (EurOtop, Van der Meer, Hunt).
6. Interpret results: The safety bar shows risk levels (safe, minor risk, structural hazard, catastrophic breach). The 2D animation visualises wave runup and potential overtopping.
7. Export PDF report: Click “Export Executive PDF Report” to generate a professional 3‑page report with all inputs, comparisons, and certification.

💡 Pro Tip: For rubble‑mound structures (riprap), use γ_f = 0.55. For smooth concrete seawalls, use γ_f = 1.0. Oblique waves (β > 0°) significantly reduce overtopping.

🏖️ Real‑World Example – Cox’s Bazar Seawall

Location: Cox’s Bazar, Bangladesh (Bay of Bengal)
Design conditions: H_s0 = 2.8 m, T_p = 9 s, water depth at toe = 6 m, slope = 1:3 (18.4°), crest freeboard = 3.5 m, riprap protection (γ_f = 0.55).
Results (EurOtop): Runup ≈ 2.95 m, overtopping ≈ 4.2 l/s/m → within safe limits for pedestrian areas.
Use the calculator below to replicate this and test design variations.

1. Design Parameters & Reduction Factors

Significant Deepwater Wave Height H_s0 (m)

Peak Wave Period T_p (s)

Water Depth at Toe h (m)

Dike Slope Angle α (degrees)

Crest Freeboard R_c (m)

Roughness γ_fSmooth concrete (1.0)Riprap / rock (0.55)Tetrapods (0.50)Grass (0.80)

Oblique wave angle β (deg)

Berm factor γ_b

Vertical wall factor γ_v

Output unitMetric (m, l/s/m)Imperial (ft, cfs/ft)

2. Analytical Output & Risk Mapping

Cross-Method Comparison Matrix

Method	Wave Runup	Overtopping	Safety Class

3. Hydrodynamic Profile & Wave Overtopping Simulation

🌊 Animated 2D profile – waves breaking and overtopping based on real‑time calculations.

❓ Frequently Asked Questions

❓ What is the Surf Similarity Parameter (ξ_m)?

It distinguishes breaking (ξ_m < 2) from non‑breaking (ξ_m > 2) waves. The calculator automatically applies different overtopping formulas accordingly.

❓ How do I choose the roughness factor?

For rock/riprap slopes, use 0.55. For smooth concrete, use 1.0. Tetrapods are around 0.5, grass 0.8. The tool includes a dropdown with typical values.

❓ Can I use this for vertical seawalls?

Yes, set slope angle to 70-75° and adjust the vertical wall factor (γ_v) to 0.8-1.0. The tool will handle the runup/overtopping parameters accurately within safety envelopes.

❓ Is the PDF report free?

Yes, completely free. The report includes all inputs, method comparison, reduction factors, and a certification page – ready for engineering submissions.

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© River Warrior Academy – Developed by Engr. Rokib Hossain | IHO S‑44 compliant | Data processed locally