IAHR World Congress 2015

Den Haag, 30th June 2015

Validation of SWAN under extreme

conditions in the Wadden Sea

Amaury Camarena

Caroline Gautier

Joana van Nieuwkoop

Introduction

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Introduction

• Hydraulic Boundary

Conditions partly derived by

the SWAN model.

• Assess the performance of

SWAN when simulating

extreme conditions.

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Study area

Ameland Eastern Wadden Sea

• Stationary SWAN computations: Storm 5th and 6th December 2013

• Several wave measuring devices available for comparison and validation

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Available data and case selection

Eight different times are selected to undertake stationary SWAN

computations (pre, during, post storm).

• Tidal phase

• No large offshore temporal variation

• Availability of data in buoys

(buoys are shown by the different colors)

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SWAN model setup

-Wind input: HARMONIE

-Wave input: Wave buoys

-Water level and current input: Delft3D-Flow coupled with waves

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SWAN settings

A-series: Reference settings, including currents (based on the

research carried out for the so-called ‘Wettelijk

toetsinstrumentarium’ (WTI) project).

B-series: Reference settings, deactivating currents.

C-series: Komen wind growth and whitecapping with delta=1. These

are the SWAN default settings in version 40.91.A.

D-series: Komen wind growth and whitecapping with delta=0.

Represent the previous default SWAN settings before version

40.91.A.

E-series: Reference settings, without enhanced whitecapping due to

currents (Cds3=0).

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Results - Ameland

• * represent the measured value at the time of the event

• + shows 1 hour after

• □ 1 hour before

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Results - Eastern Wadden Sea

• * represent the measured value at the time of the event

• + shows 1 hour after

• □ 1 hour before

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Statistical performance of SWAN - Ameland

ID SETTINGS BIAS STANDARD DEVIATION

ROOT

MEAN SQUARE

RELATIVE

BIAS

RELATIVE

STANDARD DEVIATION

NUMBER

OF SAMPLES

HM0 A Westh Cds3=0.8 -0.02 m 0.26 m 0.26 m -1.9 % 20.6 % 72

HM0 B Westh (no currents) -0.01 m 0.24 m 0.24 m -0.9 % 18.9 % 72

HM0 C Komen, δ=1 0.13 m 0.37 m 0.39 m 10.0 % 29.0 % 72

HM0 D Komen, δ=0 0.10 m 0.40 m 0.41 m 8.1 % 31.5 % 72

HM0 E Westh Cds3=0.0 0.04 m 0.29 m 0.29 m 3.5 % 23.1 % 72

TM-1,0 A Westh Cds3=0.8 -0.25 s 0.50 s 0.56 s -4.8 % 9.5 % 72

TM-1,0 B Westh (no currents) -0.41 s 0.65 s 0.77 s -7.9 % 12.4 % 72

TM-1,0 C Komen, δ=1 -0.43 s 0.71 s 0.83 s -8.3 % 13.6 % 72

TM-1,0 D Komen, δ=0 -0.86 s 0.77 s 1.15 s -16.5 % 14.7 % 72

TM-1,0 E Westh Cds3=0.0 -0.31 s 0.55 s 0.63 s -5.9 % 10.6 % 72

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Statistical performance of SWAN - Eastern Wadden Sea

ID SETTINGS BIAS STANDARD DEVIATION

ROOT

MEAN SQUARE

RELATIVE

BIAS

RELATIVE

STANDARD DEVIATION

NUMBER

OF SAMPLES

HM0 A Westh Cds3=0.8 0.20 m 0.28 m 0.34 m 10.4 % 14.6 % 48

HM0 B Westh (no currents) 0.23 m 0.28 m 0.36 m 11.8 % 14.7 % 48

HM0 C Komen, δ=1 0.35 m 0.40 m 0.53 m 18.6 % 21.1 % 48

HM0 D Komen, δ=0 0.55 m 0.55 m 0.77 m 29.0 % 28.7 % 48

HM0 E Westh Cds3=0.0 0.27 m 0.30 m 0.40 m 14.3 % 15.9 % 48

TM-1,0 A Westh Cds3=0.8 -0.3 s 0.6 s 0.7 s -5.2 % 9.7 % 48

TM-1,0 B Westh (no currents) -0.5 s 0.8 s 0.9 s -7.4 % 11.6 % 48

TM-1,0 C Komen, δ=1 -0.9 s 0.8 s 1.2 s -14.1 % 11.9 % 48

TM-1,0 D Komen, δ=0 -1.5 s 1.1 s 1.9 s -22.7 % 16.6 % 48

TM-1,0 E Westh Cds3=0.0 -0.6 s 0.6 s 0.8 s -8.3 % 9.5 % 48

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Conclusions

• The reference settings (Series-A) perform significantly better than the

standard SWAN settings especially in areas with mixed swell and wind-

sea conditions.

• The present default SWAN settings (version 40.91.A), which includes

Komen wind growth and whitecapping with delta=1 (C-series), give a

better approximation of wave conditions than previous settings (Komen

with delta=0, D-series) during extreme events on areas dominated by wind

sea and swell like the Wadden Sea.

• Whitecapping formulation and associated calibration parameters strongly

influence the results of the SWAN model.

• Although the effect of currents on wave growth is limited, it cannot be

omitted.

• Overall it is concluded that SWAN is a high quality tool to compute

nearshore waves during storms in the Wadden Sea when the adequate

combination of settings is used.

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Questions?

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Amaury Camarena Calderon Consultant / Researcher

T +31(0)88335 8029

E amaury.camarenacalderon@deltares.nl

www.deltares.com

P.O.Box 177 2600 MH Delft The Netherlands

Results - SWAN (series A) vs measurements

AZB11 AZB 31 AZB 41 AZB 51 AZB 61 AZB 12

(G1A) AZB 12

(G2A) AZB 22 AZB 32 AZB 42 AZB 52 AZB 62

T1A 0.13 -0.07 0.06 0.06 0.27 0.06 -0.01 -0.17 0.07 0.18 -0.26 -0.20 T2A 0.14 -0.07 -0.05 -0.08 0.09 0.10 0.00 -0.22 0.19 0.14 0.11 0.03 T3A 0.04 0.10 -0.01 -0.01 0.33 0.16 0.00 -0.25 0.14 0.06 0.03 0.06 T4A 0.16 -0.09 -0.02 -0.15 0.06 0.11 0.00 -0.31 -0.14 0.28 -0.17 -0.21 T5A -0.01 -0.02 0.33 0.27 0.39 -0.04 0.10 0.04 0.06 0.04 0.17 0.47 T6A -0.01 -0.16 -0.17 -0.15 0.08 -0.06 0.00 -0.37 -0.21 0.16 0.03 -0.09 T7A -0.05 0.20 0.10 0.06 0.35 0.02 0.00 -0.27 0.07 0.34 0.07 0.11 T8A 0.05 0.18 0.50 0.50 0.91 0.02 0.00 -0.38 -0.01 0.29 0.42 0.04

BRKN

(G1E)

BRKN

(G2E) WEW WEO RZGN OWEN OWEZ UHW2 LAUOT BOSZ PBW

T1E 0.00 -0.01 -0.04 0.14 0.36 0.69 0.36 0.58 0.30 0.20 0.25

T2E 0.02 0.00 -0.05 0.01 0.39 0.51 0.73 0.14 0.27 0.10 0.15

T3E -0.02 0.00 0.13 -0.05 0.39 0.21 0.23 0.27 0.15 0.00 0.08

T4E 0.02 0.00 -0.05 0.12 0.15 0.12 0.59 -0.22 0.11 -0.13 -0.12

T5E 0.01 0.00 -0.24 0.06 0.18 0.86 0.89 -0.07 0.02 0.03 0.23

T6E -0.02 0.00 -0.15 -0.04 0.02 -0.04 0.36 0.03 0.16 0.04 0.21

T7E -0.01 0.00 0.07 0.03 0.09 0.44 0.56 -0.15 0.16 -0.11 -0.06

T8E 0.01 0.00 -0.07 0.14 0.37 0.71 1.04 -0.19 0.25 0.09 0.11

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