Wave Setup Calculator

Input wave height, period, slope, and site levels. Choose methods, apply safety margin, and check freeboard. Download clear CSV and PDF reports on site.

Inputs

Typical: 0.3–6.0 m.
Typical: 4–18 s.
Example: 1V:20H → 0.05.
Use Stockdon for beaches and open coasts.
If blank, Hb is approximated as H0.
Common default: 0.78.
Datum-based mean level for your site.
Use design high tide if required.
Set 0 for non-storm conditions.
Crest level used for freeboard check.
Extra allowance for uncertainty and tolerances.

Tip: For critical designs, validate with site-specific modeling and guidance.

Example Data Table

Case H0 (m) T (s) tanβ (-) Setup (Stockdon) (m) Setup (0.17 Hb) (m)
A 1.2 8 0.05 0.35×0.05×√(1.2×99.9)=0.096 0.17×1.2=0.204
B 2.0 10 0.03 0.35×0.03×√(2.0×156.1)=0.186 0.17×2.0=0.340
C 3.5 14 0.06 0.35×0.06×√(3.5×305.9)=0.689 0.17×3.5=0.595
Values shown are illustrative and rounded.

Formulas Used

  • L0 = g·T² / (2π) (deep-water wavelength)
  • ηsetup = 0.35·tanβ·√(H0·L0) (shoreline setup method)
  • ηsetup ≈ 0.17·Hb (breaker-height estimate)
  • Total Level = SWL + Tide + Surge + ηsetup
  • Required Crest = Total Level + Margin
  • Freeboard After Margin = Crest − Required Crest

Use consistent units. Keep all elevations on the same datum.

How to Use This Calculator

  1. Enter deep-water wave height, period, and foreshore slope.
  2. Select the method that matches your site conditions.
  3. Provide SWL, tide, and surge using your project datum.
  4. Enter crest elevation and a reasonable design margin.
  5. Press calculate to view setup, levels, and freeboard risk.
  6. Download CSV or PDF to attach with site records.

Use outputs to improve coastal safety and decisions daily.

Professional Notes: Wave Setup in Construction

1) Why setup influences site safety

Wave setup is the time-averaged rise of the mean water level at the shoreline caused by breaking waves. Even 0.15–0.30 m can change access and pump requirements. On temporary works, it can reduce available freeboard, increase overtopping frequency, and elevate flooding probability behind cofferdams, causeways, and shoreline staging pads.

2) Key inputs and typical ranges

Setup scales with breaking-wave height and the foreshore slope. Construction studies commonly use significant wave heights from 0.3–2.5 m for sheltered works and 2.5–6.0 m for exposed coasts. Practical beach slopes often fall between 1:10 and 1:50, with steeper slopes tending to produce higher setup near the breakpoint.

3) From deep water to breaking conditions

The calculator accepts deep-water wave height and period because those values are usually available from buoy, hindcast, or design metocean tables. Nearshore conditions depend on shoaling, refraction, and local bathymetry. Where detailed modeling is unavailable, conservative allowances and sensitivity checks are recommended.

4) Choosing an empirical approach

Different methods reflect different datasets and assumptions. For quick planning, a conservative empirical coefficient may be used. For design reviews, compare at least two methods and document the selected basis, including shoreline type, wave climate, and the assumed breaking index.

5) Water level components must share one datum

Still water level is not just “tide.” It should combine design tide, storm surge, seasonal anomalies, and any project-required allowances. Mixing chart datum with site benchmarks is a common error. Always convert SWL, crest elevation, and output levels to the same reference.

6) Reading outputs for decisions

Use setup and total water level to evaluate temporary crest elevations, equipment placement limits, and safe access windows. The freeboard margin is a decision metric: larger margins generally reduce overtopping risk and reduce nuisance flooding that disrupts concrete pours and rebar installation.

7) Data quality and verification

Field checks improve reliability. Confirm beach slope with profiles or recent surveys, validate wave inputs against local observations, and note morphological changes after storms. If results are close to crest elevation, rerun with higher wave height, higher surge, and steeper slope to bracket uncertainty.

8) Documentation for permits and audits

Regulators and client reviewers often ask how water levels were derived for temporary works. Save CSV/PDF outputs with the chosen method, input sources, and assumptions. This supports method statements, lift plans near shore, and emergency response triggers during severe sea states.

FAQs

1) What is wave setup in simple terms?

It is the average rise of nearshore water level caused by wave breaking and momentum transfer. It is not a single wave crest; it shifts the baseline water level upward during energetic conditions.

2) How is setup different from runup?

Setup is a mean water-level increase, while runup is the maximum vertical reach of individual waves on a slope. Many coastal safety checks consider both, especially for overtopping assessments.

3) Which wave height should I enter?

Use the significant wave height that matches your design condition or forecast window. If you only have maximum wave height, convert using your standard practice, then apply a conservative margin.

4) What foreshore slope should be used?

Use the representative slope over the active surf zone, not a single point. If slopes vary, run multiple cases (steeper and flatter) and document the range for decision-making.

5) Why does the method selection matter?

Methods embed different coefficients and assumptions about breaking and beach type. Selecting the wrong method can underpredict setup. Compare methods and choose the one aligned with your shoreline conditions and conservatism needs.

6) Can I use this for seawall design?

It supports early screening and temporary works planning. For permanent coastal structures, use project standards and detailed modeling for nearshore transformation, runup, and overtopping, then document the governing load case.

7) What should I do if freeboard is small?

Increase crest elevation, restrict operations to lower sea states, add temporary protection, or revise staging locations. Also rerun with higher surge and wave height to ensure the plan remains robust under uncertainty.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.