Hanstholm Harbour Port Expansion,
Denmark
Surf Amenity Impact Assessment
Grontmij A/S, Denmark
Final Report
September 2012
This project was delivered under the DHI
Business Management System certified by
DNV to be in compliance with ISO 9001:
Quality Management System
Hanstholm Harbour Port Expansion,
Denmark
Surf Amenity Impact Assessment
Prepared for
Grontmij A/S, Denmark
Represented by
Mr Anders Helkjær
Aerial photo of Hanstholm
©Google
Project No
Classification
11810435-2
Restricted
Version
Issued
Distribution
Final Report: 1.0
18 September 2012
SBM - PRS - Archives
Authors
Simon Brandi Mortensen, DHI-AU
[email protected]
Reviewer
Peter Sloth, DK-POT
[email protected]
Approver
Jesper Fuchs, DK-POT
[email protected]
Key words
Port of Hanstholm, Denmark – Surf Amenity Impact Assessment – Wave Modelling – Harbour
Design – Screening Study
DHI• Agern Allé 5• DK-2970 Hørsholm •Denmark• Tel: +45 4516 9200 • Fax: +45 4516 9292 • [email protected] • www.dhigroup.com
Contents
1
Introduction ....................................................................................................................................................... 1
2
Executive Summary......................................................................................................................................... 3
3
Dansk Resumé ................................................................................................................................................... 5
4
4.1
4.2
4.2.1
4.2.2
4.2.3
4.2.4
4.2.5
4.3
4.4
4.5
4.6
Methodology ...................................................................................................................................................... 7
General ...................................................................................................................................................................................... 7
Description of Surfing Amenity ..................................................................................................................................... 7
Wave height ............................................................................................................................................................................ 7
Wave breaking intensity and pealing velocity ........................................................................................................ 7
Length of wave ride ............................................................................................................................................................. 9
Wind speed and direction ................................................................................................................................................ 9
Reoccurrence frequency ................................................................................................................................................ 10
Site-specific Surfing Amenity Classification .......................................................................................................... 10
MIKE 21 SW Screening Study ...................................................................................................................................... 14
Detailed Surf Impact Study using MIKE 21 BW and OPTISURF ................................................................... 15
Wind Disturbance Analysis........................................................................................................................................... 16
5
5.1
5.2
5.2.1
5.2.2
5.2.3
5.2.4
5.2.5
5.3
5.3.1
5.3.2
5.4
5.4.1
5.4.2
5.4.3
Wave-induced Surf Amenity Impact – Results .................................................................................... 21
Site-specific Surfing Amenity Classification. Existing Conditions .............................................................. 21
MIKE 21 SW Screening Study ...................................................................................................................................... 22
General ................................................................................................................................................................................... 22
Fish Factory ......................................................................................................................................................................... 23
Middles .................................................................................................................................................................................. 24
Hamborg ............................................................................................................................................................................... 25
Fisherman’s Corner .......................................................................................................................................................... 26
Detailed Surf Impact Study using MIKE 21 BW and OPTISURF ................................................................... 26
Scenario 1 ............................................................................................................................................................................. 29
Scenario 2 ............................................................................................................................................................................. 31
Wave-induced Surf Amenity Impact ......................................................................................................................... 33
Fish Factory ......................................................................................................................................................................... 33
Middles .................................................................................................................................................................................. 35
Hamborg ............................................................................................................................................................................... 36
6
6.1
6.2
6.3
Wind-induced Surf Amenity Impact - Results ..................................................................................... 39
Fish Factory ......................................................................................................................................................................... 39
Middles .................................................................................................................................................................................. 41
Hamborg ............................................................................................................................................................................... 44
7
7.1
7.2
7.3
7.4
Combined Surf Amenity Impact – Conclusions ................................................................................... 47
Fish Factory ......................................................................................................................................................................... 47
Middles .................................................................................................................................................................................. 49
Hamborg ............................................................................................................................................................................... 52
Conclusions .......................................................................................................................................................................... 54
8
References ........................................................................................................................................................ 57
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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Figures
Figure 1.1
Figure 1.2
Figure 4.1
Figure 4.2
Figure 4.3
Figure 4.4
Figure 4.5
Figure 4.6
Figure 4.7
Figure 4.8
Figure 4.9
Figure 4.10
Figure 4.11
Figure 4.12
Figure 5.1
Figure 5.2
Figure 5.3
Figure 5.4
Figure 5.5
Figure 5.6
Figure 5.7
Figure 5.8
Figure 5.9
Figure 5.10
Figure 5.11
Figure 5.12
Figure 5.13
Figure 5.14
Figure 5.15
Figure 5.16
Figure 5.17
Figure 5.18
Figure 5.19
ii
Schematic drawing illustrating the proposed port expansion ................................................................................................ 1
Five well-known surf spots are located in the close proximity to Hanstholm Harbour ............................................. 2
Windsurfer riding a spilling type wave breaker. Location: Hanstholm, Denmark ....................................................... 8
Surfer positioned in the barrel of a plunging type wave breaker. Location: Hanstholm, Denmark ..................... 8
A wave needs to be breaking successively in order to be suitable for surfing. The speed V p of which the
break point moves is called the pealing velocity ............................................................................................................................ 9
A surfer riding in the pocket, which is the optimal location to perform critical manoeuvres and maintain
speed. ................................................................................................................................................................................................................... 9
Wave rose (left) and wind rose (right) for the period 1979 – 2012. The dominant wave and wind direction
is SW to NW with the most energetic wave events occurring from the NW. Based on the modelling
described in [6]. ............................................................................................................................................................................................11
The DHI North Sea model was used to provide wind and wave data corresponding to the dates of the
reported exceptional surf days. Offshore wave data were extracted from the point marked DHI .....................13
MIKE 21 SW domain bathymetry (current port layout) ...........................................................................................................14
MIKE 21 SW domain bathymetry (future port layout) .............................................................................................................14
Detailed overview of nearfield domain resolution in MIKE 21 SW (proposed expanded layout) .......................14
MIKE 21 SW wave disturbance coefficient plots for current layout (left) and future layout (right) for an
offshore wave direction of 265 degrees WSW and a spectral peak period of 8s ..........................................................15
Example of surfing amenity analysis using OPTISURF. The black polygons mark the extent of the breaking
wave roller, while the red markers represent the pocket points .........................................................................................16
Google Earth overview of proposed port expansion and the 6 points used for assessing the combined wind
impact at Fish Factory, Middles and Hamborg ..............................................................................................................................18
Average number of windsurf/kitesurf days per year for Fakir, Fish Factory, Middles and Hamborg (Current
Layout) ..............................................................................................................................................................................................................21
Total number of windsurf/kitesurf days per year based on category (1979- March 2012) for Fish Factory,
Fakir, Middles and Hamborg (Current Layout).............................................................................................................................21
Total number of traditional surf days per year based on category (1979-2012) for Fisherman’s Corner
(Current Layout) ..........................................................................................................................................................................................22
Wave-induced impact at Fish Factory. For explanation see Section 5.2.1 ......................................................................23
Wave-induced impact at Middles. For explanation see Section 5.2.1 ...............................................................................24
Wave-induced impact at Hamborg. For explanation see Section 5.2.1 ............................................................................25
Wave-induced impact on Fisherman’s Corner. It is observed that the port expansion causes no impact on
the surf amenity at this surf spot .........................................................................................................................................................26
Wave-induced impact on Fish Factory. Scenario 1 and Scenario 2 were selected to provide a conservative
estimate of the reduction in wave-induced surf amenity ........................................................................................................27
Wave-induced impact on Middles. Scenario 1 and Scenario 2 were selected to provide a conservative
estimate of the reduction in wave-induced surf amenity ........................................................................................................28
Wave-induced impact on Hamborg. Scenario 1 and Scenario 2 were selected to provide a conservative
estimate of the reduction in wave-induced surf amenity ........................................................................................................28
Scenario 1. Significant wave height plots produced by MIKE21 BW for current (left) and future (right) port
layout .................................................................................................................................................................................................................29
Current Layout – Scenario 1. Possible surf rides during 1 hour. Each line represents the trajectory path of
a ride. The coloration of each ride represents the maximum wave face height at the position of the surfer
during the ride ..............................................................................................................................................................................................29
Future Layout – Scenario 1. Possible surf rides during 1 hour. Each line represents the trajectory path of a
ride. The coloration of each ride represents the maximum wave face height at the position of the surfer
during the ride ..............................................................................................................................................................................................29
Scenario 2. Significant wave height plots produced by MIKE 21 BW for current (left) and future (right)
port layout.......................................................................................................................................................................................................31
Current Layout – Scenario 2. Each line represents the trajectory path of a ride. The coloration of each ride
represents the maximum wave face height at the position of the surfer during the ride ........................................32
Future Layout – Scenario 2. Each line represents the trajectory path of a ride. The coloration of each ride
represents the maximum wave face height at the position of the surfer during the ride ........................................32
Average distribution of windsurf days – Current Layout (Fish Factory) .........................................................................34
Average distribution of windsurf days – Future Layout. Wave Impact only (Fish Factory) ..................................34
Yearly distribution of windsurf days – Wave impact – Category 1 (Fish Factory) ......................................................34
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 5.20
Figure 5.21
Figure 5.22
Figure 5.23
Figure 5.24
Figure 5.25
Figure 5.26
Figure 5.27
Figure 5.28
Figure 5.29
Figure 5.30
Figure 5.31
Figure 6.1
Figure 6.2
Figure 6.3
Figure 6.4
Figure 6.5
Figure 6.6
Figure 6.7
Figure 6.8
Figure 6.9
Figure 6.10
Figure 6.11
Figure 6.12
Figure 6.13
Figure 6.14
Figure 6.15
Figure 6.16
Figure 6.17
Figure 6.18
Figure 6.19
Figure 6.20
Figure 6.21
Figure 6.22
Figure 6.23
Figure 6.24
Figure 6.25
Figure 6.26
Figure 6.27
Figure 6.28
Figure 6.29
Figure 6.30
Figure 7.1
Figure 7.2
Figure 7.3
Figure 7.4
Figure 7.5
Figure 7.6
Figure 7.7
Figure 7.8
Figure 7.9
Figure 7.10
Figure 7.11
Figure 7.12
Figure 7.13
Figure 7.14
Figure 7.15
Figure 7.16
Yearly distribution of windsurf days – Wave impact – Category 2 (Fish Factory) ..................................................... 34
Yearly distribution of windsurf days – Wave impact – Category 3 (Fish Factory) ..................................................... 35
Average distribution of windsurf days – Current Layout (Middles) .................................................................................. 35
Average distribution of windsurf days – Future Layout. Wave Impact only (Middles)........................................... 35
Yearly distribution of windsurf days – Wave impact – Category 1 (Middles) ............................................................... 35
Yearly distribution of windsurf days – Wave impact – Category 2 (Middles) ............................................................... 36
Yearly distribution of windsurf days – Wave impact – Category 3 (Middles) ............................................................... 36
Average distribution of windsurf days – Current Layout (Hamborg) ............................................................................... 36
Average distribution of windsurf days – Future Layout. Wave Impact only (Hamborg)........................................ 36
Yearly distribution of windsurf days – Wave impact – Category 1 (Hamborg) ............................................................ 37
Yearly distribution of windsurf days – Wave impact – Category 2 (Hamborg) ............................................................ 37
Yearly distribution of windsurf days – Wave impact – Category 3 (Hamborg) ............................................................ 37
Average distribution of windsurf days – Current Layout (Fish Factory)......................................................................... 39
Average distribution of windsurf days – Future Layout (Fish Factory) ........................................................................... 39
Average distribution of Kitesurf days – Current Layout (Fish Factory) .......................................................................... 40
Average distribution of Kitesurf days – Future Layout – Kite impact only (Fish Factory) .................................... 40
Yearly distribution of windsurf days – Wind impact – Category 1 (Fish Factory) ...................................................... 40
Yearly distribution of Kitesurf days – Wind impact – Category 1 (Fish Factory) ........................................................ 40
Yearly distribution of windsurf days – Wind impact – Category 2 (Fish Factory) ...................................................... 40
Yearly distribution of kitesurf days – Wind impact – Category 2 (Fish Factory)......................................................... 41
Yearly distribution of windsurf days – Wind impact – Category 3 (Fish Factory) ...................................................... 41
Yearly distribution of kitesurf days – Wind impact – Category 3 (Fish Factory)......................................................... 41
Average distribution of windsurf days – Current Layout (Middles) .................................................................................. 42
Average distribution of windsurf days – Future Layout – Wind impact only (Middles) .......................................... 42
Average distribution of kitesurf days – Current Layout (Middles)..................................................................................... 42
Average distribution of kitesurf days – Future Layout – Kite impact only (Middles) ............................................... 42
Yearly distribution of windsurf days – Wind impact – Category 1 (Middles) ............................................................... 42
Yearly distribution of kitesurf days – Wind impact – Category 1 (Middles) .................................................................. 43
Yearly distribution of windsurf days – Wind impact – Category 2 (Middles) ............................................................... 43
Yearly distribution of kitesurf days – Wind impact – Category 2 (Middles) .................................................................. 43
Yearly distribution of windsurf days – Wind impact – Category 3 (Middles) ............................................................... 43
Yearly distribution of kitesurf days – Wind impact – Category 3 (Middles) .................................................................. 44
Average distribution of windsurf days – Current Layout (Hamborg) ............................................................................... 44
Average distribution of windsurf days – Future Layout – Wind impact only (Hamborg) ....................................... 44
Average distribution of kitesurf days – Current Layout (Hamborg).................................................................................. 45
Average distribution of kitesurf days – Future Layout – Kite impact only (Hamborg) ............................................ 45
Yearly distribution of windsurf days – Wind impact – Category 1 (Hamborg) ............................................................ 45
Yearly distribution of kitesurf days – Wind impact – Category 1 (Hamborg) ............................................................... 45
Yearly distribution of windsurf days – Wind impact – Category 2 (Hamborg) ............................................................ 45
Yearly distribution of kitesurf days – Wind impact – Category 2 (Hamborg) ............................................................... 45
Yearly distribution of windsurf days – Wind impact – Category 3 (Hamborg) ............................................................ 46
Yearly distribution of kitesurf days – Wind impact – Category 3 (Hamborg) ............................................................... 46
Average distribution of windsurf days – Current Layout (Fish Factory)......................................................................... 47
Average distribution of windsurf days – Future Layout – Total impact (Fish Factory) ........................................... 47
Average distribution of kitesurf days – Current Layout (Fish Factory) ........................................................................... 47
Average distribution of kitesurf days – Future Layout – Total impact (Fish Factory) .............................................. 47
Yearly distribution of windsurf days – Total impact – Category 1 (Fish Factory) ...................................................... 48
Yearly distribution of kitesurf days – Total impact – Category 1 (Fish Factory) ......................................................... 48
Yearly distribution of windsurf days – Total impact – Category 2 (Fish Factory) ...................................................... 48
Yearly distribution of kitesurf days – Total impact – Category 2 (Fish Factory) ......................................................... 48
Yearly distribution of windsurf days – Total impact – Category 3 (Fish Factory) ...................................................... 49
Yearly distribution of kitesurf days – Total impact – Category 3 (Fish Factory) ......................................................... 49
Average distribution of windsurf days – Current Layout (Middles) .................................................................................. 50
Average distribution of windsurf days – Future Layout – Total impact (Middles)..................................................... 50
Average distribution of kitesurf days – Current Layout (Middles)..................................................................................... 50
Average distribution of kitesurf days – Future Layout – Total impact (Middles) ....................................................... 50
Yearly distribution of windsurf days – Total impact – Category 1 (Middles)................................................................ 50
Yearly distribution of kitesurf days – Total impact – Category 1 (Middles) .................................................................. 50
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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Figure 7.17
Figure 7.18
Figure 7.19
Figure 7.20
Figure 7.21
Figure 7.22
Figure 7.23
Figure 7.24
Figure 7.25
Figure 7.26
Figure 7.27
Figure 7.28
Figure 7.29
Figure 7.30
Yearly distribution of windsurf days – Total impact – Category 2 (Middles) ................................................................51
Yearly distribution of kitesurf days – Total impact – Category 2 (Middles) ...................................................................51
Yearly distribution of windsurf days – Total impact – Category 3 (Middles) ................................................................51
Yearly distribution of kitesurf days – Total impact – Category 3 (Middles) ...................................................................51
Average distribution of windsurf days – Current Layout (Hamborg)................................................................................52
Average distribution of windsurf days – Future Layout – Total impact (Hamborg) ..................................................52
Average distribution of kitesurf days – Current Layout (Hamborg) ..................................................................................52
Average distribution of kitesurf days – Future Layout – Total impact (Hamborg) .....................................................52
Yearly distribution of windsurf days – Total impact – Category 1 (Hamborg) .............................................................53
Yearly distribution of kitesurf days – Total impact – Category 1 (Hamborg) ................................................................53
Yearly distribution of windsurf days – Total impact – Category 2 (Hamborg) .............................................................53
Yearly distribution of kitesurf days – Total impact – Category 2 (Hamborg) ................................................................53
Yearly distribution of windsurf days – Total impact – Category 3 (Hamborg) .............................................................54
Yearly distribution of kitesurf days – Total impact – Category 3 (Hamborg) ................................................................54
Tables
Table 2.1
Tabel 3.1
Table 4.1
Table 4.2
Table 4.3
Table 4.4
Table 4.5
Table 5.1
Table 5.2
Table 5.3
Table 5.4
Table 5.5
Table 5.6
Table 5.7
Table 5.8
Table 5.9
Table 5.10
Table 5.11
Table 5.12
Table 5.13
Table 5.14
Table 5.15
Table 5.16
Table 5.17
Table 5.18
Table 6.1
Table 6.2
Table 6.3
Table 6.4
Table 6.5
Table 6.6
Table 7.1
Table 7.2
Table 7.3
Table 7.4
Table 7.5
iv
Schematic overview of surfing amenity impact due to the proposal Hanstholm Port Expansion ......................... 3
Oversigtstabel af den estimerede påvirkning på surf forholdene som følge af den planlagte udvidelse af
Hanstholm Havn ............................................................................................................................................................................................. 5
28 reported exceptional surf events (Category 3) during the period of 2010 to 2012 .............................................12
Wind and wave conditions for Category 1, 2 and 3 windsurfing conditions ..................................................................12
Surf category classification (Fisherman’s Corner) ......................................................................................................................13
Definition of turbulence index for different types of terrain roughness (Translated from Grontmij [2]) .......17
Threshold values for N during different mean wind speeds (30 minute duration) ....................................................18
Number of surfable days per year – Fakir, Fish Factory, Middles and Hamborg .........................................................21
Number of surfable days per year – Fisherman’s Corner ........................................................................................................22
Scenario 1 and Scenario 2 were used to provide a detailed investigation of the wave-induced impact on
surfing amenity using MIKE 21 BW and OPTISURF ...................................................................................................................26
Number of surfable rides/hour for Fish Factory (Current Layout) ....................................................................................30
Number of surfable rides/hour for Fish Factory (Future Layout) ......................................................................................30
Number of surfable rides/hour for Middles (Current Layout)..............................................................................................30
Number of surfable rides/hour for Middles (Future Layout) ................................................................................................30
Number of surfable rides/hour for Hamborg (Current Layout)...........................................................................................31
Number of surfable rides/hour for Hamborg (Future Layout) .............................................................................................31
Number of surfable rides/hour for Fish Factory Scenario 2 (Current Layout) .............................................................32
Number of surfable rides/hour for Fish Factory Scenario 2 (Future Layout) ...............................................................32
Number of surfable rides/hour for Middles Scenario 2 (Current Layout) ......................................................................33
Number of surfable rides/hour for Middles Scenario 2 (Future Layout) ........................................................................33
Number of surfable rides/hour for Hamborg Scenario 2 (Current Layout) ...................................................................33
Number of surfable rides/hour for Hamborg Scenario 2 (Future Layout) .....................................................................33
Wave-induced impact to surfing amenity at Fish Factory .....................................................................................................34
Wave-induced impact to surfing amenity at Middles ...............................................................................................................35
Wave-induced impact to surfing amenity at Hamborg ............................................................................................................36
Wind-induced impact to surfing amenity at Fish Factory (Windsurfing) ....................................................................39
Wind-induced impact to surfing amenity at Fish Factory (Kitesurfing).......................................................................39
Wind-induced impact to surfing amenity at Middles (Windsurfing)..............................................................................42
Wind-induced impact to surfing amenity at Middles (Kitesurfing) ................................................................................42
Wind-induced impact to surfing amenity at Hamborg (Windsurfing) ..........................................................................44
Wind-induced impact to surfing amenity at Hamborg (Kitesurfing) .............................................................................44
Combined impact to surfing amenity at Fish Factory (Windsurfing) ............................................................................47
Combined impact to surfing amenity at Fish Factory (Kitesurfing) ...............................................................................47
Combined impact to surfing amenity at Middles (Windsurfing) ......................................................................................49
Combined impact to surfing amenity at Middles (Kitesurfing) .........................................................................................49
Combined impact to surfing amenity at Hamborg (Windsurfing) ...................................................................................52
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Table 7.6
Table 7.7
Combined impact to surfing amenity at Hamborg (Kitesurfing) ..................................................................................... 52
Schematic overview of surfing amenity impact due to the proposed Hanstholm Port Expansion ..................... 54
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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DHI
Archiving: All standard project files (documents, etc) are archived in DHI project site. Any other project files (set-up files, forcing data,
model output, etc) are archived on an external hard drive located in the DHI project archive under Project No 11810435.
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11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
1
Introduction
DHI has been commissioned by Grontmij A/S to investigate the potential impact to surfing
amenity at five surf spots/areas caused by a proposed expansion of Port of Hanstholm, see
Figure 1.1 and Figure 1.2.
The adjacent coastline to Port of Hanstholm is home to some of the best surf spots in Northern
Europe for kitesurfing and wave performance windsurfing.
A unique bathymetry combined with the frequent occurrence of large waves and strong winds,
has contributed to the area’s worldwide reputation as a unique surfing area.
Figure 1.1
Schematic drawing illustrating the proposed port expansion
Due to the significant seaward extension of the port, it is expected that the nearby surf spots
could experience a reduction in wave heights due to the increased sheltering during some wave
conditions. Furthermore, the new port infrastructure and proposed wind turbines may result in
reduced wind speeds and increased turbulence at the surf areas.
Five surf spots are located in close proximity of Port of Hanstholm. An overview of all five surf
spots adjacent to Port of Hanstholm is presented in Figure 1.2.
The surf spot ‘Middles’ is the most famous and is ranked as one of the best spots for wave
performance windsurfing in Northern Europe. Middles is also a very popular spot among
kitesurfers and to a lesser degree among traditional style surfers (no sail or kite). The adjacent
surf spots ‘Fish Factory’ and ‘Hamborg’ are also regarded as high-quality spots mostly for wave
performance windsurfing and kitesurfing. On occasion, Fish Factory also produces good
conditions for traditional style surfing. The surf spot Fakir is utilized by all types of surfers.
Fisherman’s Corners is only used for traditional style surfing. Fakir is located inside the
proposed port expansion and therefore, no assessment of this surf spot has been included in this
report.
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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Through consultation with the local surfing community it has been reported that Fakir, Fish
Factory, Middles and Hamborg all provide good wind and kitesurfing conditions in similar wave
and wind conditions, but that Middles is the preferred option in 8 out of 10 cases.
Figure 1.2
2
Five well-known surf spots are located in the close proximity to Hanstholm Harbour
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
2
Executive Summary
DHI has been commissioned by Grontmij A/S to investigate the potential impact to surfing
amenity to five surf spots caused by the proposed expansion to Hanstholm Port and its influence
on the local wave and wind field.
From consultation with the local surfing community, the existing surfing amenity was
quantified. Based on 33 years of local wave and wind hindcast data, the historic number of
surfable days was estimated. Each surf event was assigned a quality category from 1 to 3 to
provide a distinction between an exceptional surf event, good surf event, and a surfable event.
Based on above categorization, it was estimated that the current annual average number of
surfable days is 76 days for the four surf spots located east of the port (Fakir, Fish Factory,
Middles and Hamborg) with 30% of the days being categorized as exceptional surf events.
The average number of surf days for Fisherman’s Corner was 4. As early stages in this study
demonstrated a zero impact for this surf spot, no quality indexing was carried out for
Fisherman’s Corner. The surf spot Fakir is located within the proposed port expansion and will
therefore not be included in this study.
Using a state-of-the-art numerical modelling approach, a quantitative analysis of the resulting
impact on surfing amenity due to the proposed port expansion was carried out. Wave and windinduced impact was investigated separately, followed by a combined impact analysis.
A schematic overview of the resulting calculated impacts is presented in Table 2.1.
Surf Spot
Fisherman’s Corner
Fakir
Fish Factory
Middles
Hamborg
Table 2.1
Wave-Induced Impact
No Impact
High
Small
Very Small
Wind-Induced Impact
No significance
High
Moderate
Small
Combined Impact
No Impact
High
Moderate
Small
Schematic overview of surfing amenity impact due to the proposal Hanstholm Port Expansion
The calculated surfing amenity impact for each surf spot was concluded to be the following:

Fisherman’s Corner can expect no impact to surfing amenity caused by the proposed
port expansion.

Fish Factory will experience a significant and frequent decrease in local wave heights
and hence a significant reduction of the number of rideable waves, their size and the
average ride length during a typical surf event. The surf spot is also expected to
experience a significant reduction in surfing amenity due to increased wind turbulence
and wind gustiness. The total number of surfable days per year is reduced 18-19% due
to increased wind sheltering. Both wave and wind-induced impact will separately
remove good and exceptional surf days.

Middles is located further away from the proposed port expansion, and will experience
a much smaller impact than Fish Factory. Being the preferred surf spot for windsurfing
and kitesurfing in 8 out of 10 surf events, the surfing amenity impact for Middles is
considered to be of the greatest importance for the area. The impact at Middles is
expected to be dominantly caused by increased wind-induced turbulence and gustiness.
The wave-induced impacts are expected to be minor and occur mostly during wave
conditions with less energetic wave conditions. The total reduction in Category 3 is 2226% and 25%-33% for Category 2 events following the proposed port expansion. The
total number of surfable days is reduced by 11-12%. The reduction in Category 3 and 2
events means that approximately every third to fourth good or exceptional surf day will
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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disappear. The reduction of high quality surf events may be frustrating to the surfing
community, but it is not expected to jeopardize the surf spots status as a world class
surf spot. As a result, a moderate and mostly wind-induced reduction in surfing
amenity is expected at Middles.

4
Hamborg is the surf spot located furthest away from the proposed port expansion. It
experiences very little wave-induced impact and only little wind-induced impact. The
total number of surfable days is reduced by 5% and the reduction in Category 3 and
Category 2 is 9-13%. As a result, the surfing amenity at Hamborg is considered to be
largely unaffected by the proposed Hanstholm Port Expansion.
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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Dansk Resumé
I forbindelse med den planlagte udvidelse af Hanstholm Havn har Grontmij A/S anmodet DHI
om at undersøge den mulige påvirkning af den planlagte udvidelse på surf forholdene i området,
idet udvidelsen må forventes at påvirke de lokale vind- og bølgeforhold.
På baggrund af konsultationer med lokale surfere, er kvaliteten og hyppigheden af de
nuværende surf-forhold blevet kvantificeret. Dette er bl.a. gennemført ved at sammenholde
datoer for rapporterede surf-forhold med historisk bølge- og vinddata for området.
Kvaliteten af surf-dage er blevet bedømt på en skala fra 1 til 3. En Kategori 3 surf-dag svarer til
en exceptionel god surf-dag, som gør området berømt for surfing og muliggør afholdelse af
internationale konkurrencer. Kategori 2 surf-dage betegnes som gode surf-dage, der muliggør
en bred udøvelse af de fleste surf-manøvrer. En Kategori 1 surf-dag betegnes som en dag, hvor
surfing er mulig. Ud fra denne kategorisering er det estimeret, at det nuværende gennemsnitlige antal surf-dage pr. år er 76 for de fire surf-spots beliggende øst for havnen (Fakir, Fish
Factory, Middles og Hamborg – se Figur 1.2). 30% af disse dage kan klassificeres som
exceptionelle surf-dage (Kategori 3). For området Fisherman’s Corner blev det på et tidligt
tidspunkt i projektet fastslået, at området ikke vil blive påvirket af havneudvidelsen, og dette
område er ikke behandlet i detaljer. Surfspottet Fakir er beliggende indenfor den planlagte
havneudvidedelse og vil derfor ikke blive medtaget i dette studie.
Ved hjælp af en række numeriske modeller er der fortaget en kvantitativ analyse af den
forventede påvirkning på surf-forholdene som følge af havneudvidelsen, hvorefter en surfkvalitetsanalyse er blevet gennemført for at dokumentere påvirkningen af surf-kvaliteten/
antal surf-dage. Undersøgelsen er fortaget for henholdsvis bølger og vind separat og for den
kombinerede påvirkning af vind og bølger.
Vindanalysen er udført af DTU Vindenergi (Grontmij [2]) og omfatter en undersøgelse af de
mulige læ-virkninger og øgede turbulensforhold, som den nye havn ville forårsage ved de
forskellige surf-områder.
Bølgeanalysen er foretaget af DHI og omfattede en kombination af en overordnet kvantitativ
analyse af bølgeforholdene samt en detaljeret bølgeanalyse, som muliggør en nøjagtig bølge-forbølge surf-kvalitetsanalyse.
På baggrund af bølge- og vindanalysen har DHI gennemført en kvantificering af havneudvidelsens forventede indflydelse på antallet af surf-dage og den forventede kvalitet.
En oversigtstabel af den estimerede påvirkning er angivet i Tabel 3.1.
Surf Spot
Fisherman’s Corner
Fakir
Fish Factory
Middles
Bølge påvirkning
Ingen indflydelse
Stor negativ indflydelse
Lille negativ indflydelse
Hamborg
Meget lille negativ
indflydelse
Tabel 3.1
Vind påvirkning
Ingen indflydelse
Stor negativ indflydelse
Moderat negativ
indflydelse
Lille negativ indflydelse
Samlet påvirkning
Ingen indflydelse
Stor negativ indflydelse
Moderat negativ
indflydelse
Lille negativ indflydelse
Oversigtstabel af den estimerede påvirkning på surf forholdene som følge af den planlagte udvidelse af
Hanstholm Havn
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
5
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På baggrund af den samlede undersøgelse konkluderes følgende:
6

Surf-forholdene ved Fisherman’s Corner vil ikke blive påvirket som følge af
havneudvidelsen.

Surf-forholdene ved Fish Factory vil opleve en hyppig og signifikant nedgang i lokale
bølgehøjder, og det typiske antal rid-bare bølger samt deres rid-bare længde forventes
at blive markant mindre. Surf-området forventes ligeledes at opleve en nedgang i surfkvaliteten som følge af forøget vindturbulens og mere stødende vind. Det totale antal af
surf-bare dage pr. år forventes at blive reduceret med 18-19% på grund af forøget læpåvirkninger på vinden. De kombinerede bølge- og vind-inducerede ændringer
forventes at eliminere de gode og exceptionelle surf-dage. Som følge af dette forventes
det, at Fish Factory vil miste sin status som et godt surf-område som følge af
havneudvidelsen.

Havneudvidelsens indflydelse på surf-området Middles forventes at blive langt mindre
end for Fish Factory. Værende det foretrukne surfspot for windsurfing og kitesurfing i
8 ud af 10 surf-dage regnes indflydelsen på surf-kvaliteten for Middles for værende af
den højeste betydning. Den forventede nedgang i surf-kvalitet vil primært være forsaget
af vinden på grund af øget turbulens og mere stødende vind. Påvirkningen af
bølgefeltet ved Middles forventes at være lille. Den forventede nedgang af exceptionelle
surf-dage for windsurfing og kitesurfing er henholdsvis 26% og 22%. Den forventede
nedgang af gode surf-dage for windsurfing og kitesurfing er henholdsvis 25% og 33%.
Den totale nedgang i surfbare dage er 11-12% for henholdsvis windsurfing og
kitesurfing. Påvirkning er primært forårsaget af ændringer af vindforholdene.
Reduktionen af gode og exceptionelle surf dage betyder, at hver tredje til fjerde af disse
dage vil forsvinde, i gennemsnit, men nedgangen forventes ikke så drastisk, at surf
spottet vil miste sin status som et verdensklasse- surfspot for windsurfing og
kitesurfing. Derfor vurderes havneudvidelsens påvirkning på surf-kvaliteten ved
Middles til at være moderat.

Surf-området Hamborg forventes at opleve en meget lille ændring af vind- og bølgeforholdene under typiske surf-forhold. Den totale nedgang i surfbare dage er 5% for
både vindsurfing og kitesurfing. Den totale forventede nedgang af exceptionelle surfdage for windsurfing og kitesurfing er 9% Den totale forventede nedgang af gode surfdage for windsurfing og kitesurfing er henholdsvis 13% Det konkluderes, at Hamborg
vil være stort set upåvirket af den planlagte havneudvidelse.
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
4
Methodology
4.1
General
The surfing amenity analysis presented in this report will consist of the following components:




Description and categorization of surfing amenity
Systematic wave impact screening study using the numerical wave model MIKE 21 SW
Analysis and implementation of a wind disturbance study for Fish Factory, Middles and
Hamborg carried out by DTU Vindenergi (Grontmij [2] and DTU [4])
Detailed surfing amenity assessment study for two representative surf events using the
numerical models MIKE 21 BW and OPTISURF.
Detailed descriptions of each component are presented below.
Fish Factory, Middles and Hamborg are dominantly used by wind and kitesurfers. Resultantly,
the surfing amenity at these spots is sensitive to changes in both the local wind and wave field.
Adverse impacts to traditional style surfing are considered dependent on wave-induced impact
only.
Fisherman’s Corner is not adversely impacted by changes to the local wind field. Resultantly,
the surf amenity impact at this surf spot is only assessed based on changes in the wave field.
4.2
Description of Surfing Amenity
The term “surfing amenity” covers the quantification of the achieved aesthetical value of surfing
as experienced by the surfing practitioner. This study incorporates a description of the three
main groups of surfing practitioners frequenting the area: surfers, windsurfers and kitesurfers.
For all three surfing disciplines, the surfing amenity depends on the following key parameters:





4.2.1
Wave height
Wave breaking intensity and pealing velocity
Length of wave ride
Wind speed and wind direction
Reoccurrence frequency
Wave height
The wave height is one of the most governing elements determining the level of surfing amenity.
A large wave height allows windsurfers and kitesurfers to perform higher jumps, and increases
the speed and level of excitement experienced during a wave ride for all three surf disciplines.
The availability of large waves is considered to be among most important factors in attracting
international surf tourism and world-ranking competitions.
4.2.2
Wave breaking intensity and pealing velocity
For surfing purposes, the wave breaking intensity type is a measure for the behaviour of the
overturning/collapsing motion occurring during wave breaking. The wave breaker type is
governed by the ratio between the wave height, wave period and the local bed gradient which is
called the Iribarren number.
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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For large wave height to wave period ratios and for mild bed slopes, wave breaking will occur as
spilling breakers. Spilling breakers are the least energetic type of wave breaking, where the
upper part of the wave crest collapses on itself and forms a roller of turbulent white water
travelling the wave celerity.
For smaller wave height to wave period ratios and for steeper bed slopes, the wave breaker type
becomes a plunging. For plunging wave breakers, the wave crest reaches a greater steepness
than spilling breakers before collapsing as an overturning “plunging” jet. In some instances, the
overturning motion occurs so violently that the plunging jet forms a tubular shape (surf term:
barrel) with the unbroken wave crest, in which an experienced traditional style surfer can
position himself during his wave ride. This type of manoeuvre is only possible for a traditional
style surfer. However, the plunging wave does still offer challenging and attractive conditions
for also windsurfers and kitesurfers when positioned further away from the zone of the
overturning jet. The two types of wave breaker types are illustrated in Figure 4.1 and Figure
4.2.
Figure 4.1
Windsurfer riding a spilling type wave
breaker. Location: Hanstholm, Denmark
Figure 4.2
Surfer positioned in the barrel of a plunging
type wave breaker. Location: Hanstholm,
Denmark
A surfable wave requires the front part of the wave crest (surf term: wave face) to exceed
critical steepness allowing the gravity component to become large enough for the surfboard to
obtain planning on the inclined free surface of the unbroken wave crest. Critical steepness is
only obtained shortly before the occurrence of wave breaking. As a result, the transverse
breaking pattern of a wave is required to be successive (either left to right or right to left) in
order for it to be surfable. The transition zone between broken and unbroken wave is in surfing
terminology called “the pocket”, which is the zone where the surfer must position himself in
order to sustain his wave ride.
The successive breaking pattern of a surfable wave is called “wave pealing” in surfing
terminology and its progression causes the pocket to continuously move away from the initial
point of wave breaking initiation. The principle is illustrated in Figure 4.3 and Figure 4.4. The
speed of which it moves is referred to as the “pealing velocity”, Vp, and corresponds to the
minimum average speed, Vs, that the surfer needs to sustain in order to avoid being outrun by
the wave. The minimum critical wave steepness and the maximum surf speed are depending
both on the surfer’s skill level and type of surf craft he is using. Traditional style surfers use the
wave as the sole source of propulsion, and the speed of which he moves depends greatly on
experience and ability.
8
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 4.3
A wave needs to be breaking successively
in order to be suitable for surfing. The speed
Vp of which the break point moves is called
the pealing velocity
Figure 4.4
A surfer riding in the pocket, which is the
optimal location to perform critical
manoeuvres and maintain speed.
Windsurfers and kitesurfers can utilize the force of the wind to maintain planning without being
dependent on the wave as the only energy source. This allows for greater freedom to ride waves
of less steepness and to move faster on rapid breaking waves.
The combination of wave breaking intensity and pealing velocity is governing parameters for
both the maximum length and duration of each wave ride and the level of excitement
experienced during a wave ride. Fast-moving plunging waves of high intensity, combined with
large wave heights, are key components in achieving world-class surfing amenity attractive to
elite surfing athletes and large-scale international surfing tourism and competitions.
4.2.3
Length of wave ride
The maximum wave ride length is governed by the distance where successive breaking
(pealing) occurs and is also limited by the maximum speed that the surfer can maintain if the
pealing velocity is very fast. The wave ride length is directly proportional to the duration the
surfer can ride the wave and perform maneuverers. Surf spots offering long wave rides
contribute to a high surfing amenity along with large wave height and large breaking intensity.
The preferential weighting between each component is highly subjective for surfer to surfer.
Some surfers will prefer a short ride on a large and intensively breaking wave. Others prefer a
very long wave ride, even if the wave height is smaller and is breaking with less intensity.
4.2.4
Wind speed and direction
Wind speed and direction are important aspects in all three described surfing disciplines.
Traditional style surfers obtain the best surfing conditions during very light winds from land,
which prevent locally-generated wind-waves in favour of the longer period swell. These types
of waves break with greater intensity, typically offer the longest rides, and are easier and more
predictable to surf. Surfing can also occur in strong winds from seaward directions, but usually
at the expense of significantly deteriorated and less predictable conditions.
Wave performance windsurfing and kitesurfing requires the wind direction to be approximately
parallel to the beach/waves (surf term: side-shore). This allows the surfers to obtain maximum
speed perpendicular to the incoming waves allowing them to carry out jumps on the way
seaward and ride the unbroken wave faces on the way back.
The wind and kitesurfer also requires a minimum wind speed in order to surf. The minimum
wind speed depends on the size of the sail or kite, but is for wave riding purposes about 7m/s.
For increasing wind speeds, the surfer needs to use smaller sails/kites in order to still being able
to safely operate his equipment. Each sail and kite size compares to an optimum wind speed.
The wind tolerance from its optimum wind speed for each sail/kite is approximately ±2m/s
depending on design. Resultantly, the wind and kitesurfer is also affected by the level of wind
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
9
DHI
turbulence causing the instantaneous wind speed to fluctuate from the mean level. A rapid
temporary increase in wind speed (wind gusts) can cause potentially dangerous conditions,
especially during jumps, while a sudden drop in wind speed can make the surfer unable to
maintain planning and prevent him from carry out manoeuvres or jumps.
4.2.5
Reoccurrence frequency
The reoccurrence frequency of surfable conditions is one of the most governing factors in
determining the level of surfing amenity generated by a surf spot. When defining surfable
conditions, it is necessary to distinguish between the reoccurrence of what satisfies the
minimum requirements for being considered a surfable event, and what is considered a good
surf event or an exceptionally good surf event.
The overall frequency of surfable days (Category 1) governs how often resident surfers and
visiting surf tourists can perform their sport. As with most other active amateur sports athletes,
most surfers prefer to be able to go surfing at least 1-2 times per week on average, which also
corresponds to at least a couple of guaranteed surf sessions during a typical 1-2 week surfing
holiday. If the overall frequency of surfable days in an area is less, it usually significantly
negatively affects the surfing amenity as the area will be given a low prioritization by active
practitioners and surf tourists.
A larger proportion of good surf conditions (Category 2) increase a surf spot’s attractiveness in
particular to more experienced surfers. It also makes the area more attractive to surf tourists. A
regular reoccurrence of good surf days also makes the surf spot attractive to regional
competitions and provides the necessary training grounds for developing local elite surfing
athletes capable of competing on a national to international level.
Exceptional surf conditions (Category 3) are usually considered rare and highly treasured
events for most surf spots around the world. A regular occurrence of exceptional surf
conditions can make a local area highly attractive place to live to active surfers and their families
as well as a popular holiday destination for visiting surfers from all over the world. Such areas
are usually frequented regularly by world-class surfing athletes and often host large and
prestigious international surfing competitions.
4.3
Site-specific Surfing Amenity Classification
As illustrated in Figure 4.5 and Figure 4.6, the wave climate offshore Hanstholm Harbour is
dominated by waves from a southwest to northwest window. The wave and wind time-series
data is based on a 33-year (1979-2012) North Sea hindcast study containing 1-hourly values of
wave and wind integral parameters. The dataset was generated by the DHI North Sea MIKE 21
SW model and extracted 1km NW from the existing harbour entrance at a water depth of 23m.
The modelling is described in [6]. The extraction point is marked DHI buoy in Figure 4.6.
Significant wave heights frequently exceed 2m, and wave height of 4-5m usually occurs several
times each year. As for most areas in the North Sea, the wave climate of Hanstholm Harbour is
dominated by fetch-limited conditions and a high corelation between offshore wind and wave
direction, as well as nearshore wind speed and significant wave height. During most wave
events, the spectral peak wave period is between 6-8s, but does on occasion exceed 12s.
10
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 4.5
Wave rose (left) and wind rose (right) for the period 1979 – 2012. The dominant wave and wind direction is
SW to NW with the most energetic wave events occurring from the NW. Based on the modelling described
in [6].
The surf spots Middles, Fish Factory, Fakir and Hamborg are all located east of Port of
Hanstholm and rely on wave refraction to transform the rough and frequently stormy offshore
wave field into clean and organised successively breaking waves suitable for surfing.
Fisherman´s Corner is located on the south side of the port, and usually only works during
infrequent events of large waves from the NNE generated by strong winds through Skagerrak.
Surfing amenity will in the following be classified into the following three categories:



Category 1 - Surfable Surfing Conditions
Category 2 – Good Surfing Conditions
Category 3 – Exceptional Surfing Conditions
Category 1 conditions define the minimum threshold conditions for wind and kitesurfing to
occur and are defined purely based on the minimum required wind speed and wind direction
window for the surfers to obtain sufficient wind to be surfing/sailing. It is expected that most
wave conditions during Category 1 events are too small for any significant wave performance to
occur. As an exception, Category 1 also defines all surfable conditions for Fisherman’s Corner
since no higher order quality ranking was specified for this surf spot. The Category 1 criterion
for Fisherman’s Corner does, unlike for the remaining surf spot, require substantial wave action
to occur (but no wind).
Category 2 conditions describe good surfing days and are defined by higher wind speed and
offshore wave height. A good surfing day consists of sufficient wind conditions to obtain speed
and planning and sufficient wave heights to carry out some wave riding and jumping.
Category 3 conditions describe exceptionally good surfing conditions that aside from adequate
wind conditions also require a certain combination of wave height, wave period and wave
direction to obtain optimum wave breaking conditions to occur.
Conditions defining Category 1 and Category 2 type conditions were based on input parameters
from the local surfing community representative, Mr Rasmus Johnsen. Category 3 type
conditions were calculated based on 28 historical events with exceptional surfing conditions
that occurred during the period of 2010 to 2012. The events were reported by current Danish
Wave Performance Windsurfing Champion, Mr Kenneth Danielsen.
All reported events referred to the surf spot Middles. No reports of historical exceptional events
could be obtained for the remaining four surf spots as a part of this study, but through
correspondence with Rasmus Johnsen, it was confirmed that the optimum surf conditions for
Fish Factory and Hamborg occurred during very similar conditions. As a result, the Middles
Category 3 events were considered representative also for these spots.
The reported Category 3 events at Middles were not logged systematically as part of an on-going
survey, but based partly on memory and partly on the documented exceptional conditions
occurring during national and international championships. Resultantly, the 3-year record of
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
11
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Category 3 events could not be regarded as statistically representative for the frequency of
reoccurrence of such events, but could still serve to outline an envelope of conditions providing
exceptional surfing events. The reported surf events are presented in Table 4.1. Corresponding
historical records of offshore wind and wave data were obtained using the DHI North Sea
numerical wave model. After cross-referencing the reported dates to available historical
records of wind and wave conditions, it was decided, in agreement with the local surfing
community representative, to disregard five of the reported events due to one of the following
obvious discrepancies:
1. The maximum wind speed was too low (5m/s)
2. The maximum wind direction was less than 200 degrees SSE
The disregarded events are marked in red in Table 4.1. It is anticipated that the lack of precision
in the logging method is the cause of this discrepancy.
Dato
20110127
20110203
20110205
20110309
20110310
20110311
20110324
20110624
20110628
20110922
20110923
20111007
20111011
20111215
20111226
20100610
20100819
20100827
20101103
20090922
20091006
20091007
20110809
20111020
20110915
20120328
20120329
20120330
Table 4.1
Spot
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Middles
Median Max Median Max Median Mean Median Wind Max Wind Min Wind Median Wind Max Wind
Hs
Hs
Tp
Tp Wave Direction
Speed
Speed
Direction
Direction
Direction
0.7
0.7
9.1
9.4
302
3.3
5
14
221
284
2.5
2.6
8.3
9.0
265
12.6
14
257
264
271
3.4
3.5
10.2 10.5
275
15.1
16
259
272
275
1.9
2.5
8.2
8.9
261
10.9
13
226
247
268
2.6
3.1
9.3
9.8
259
14.9
15
200
228
239
2.4
2.5
9.0 10.2
265
11.4
13
249
253
260
2.0
2.2
6.8
7.3
291
10.5
11
272
282
291
2.3
2.5
6.7
6.9
287
12.9
13
275
276
282
0.5
0.5
6.5
6.5
233
7.7
9
128
143
153
2.4
2.7
8.4
8.4
268
11.8
14
253
261
266
1.7
1.9
7.5
8.1
276
8.9
10
242
262
270
3.0
3.9
8.4
9.4
297
15.2
17
264
300
310
2.4
2.9
8.0
8.3
286
11.6
14
278
285
298
2.2
2.6
9.4
9.4
269
9.2
12
212
241
247
2.6
2.7
10.0 12.5
265
13.2
14
228
232
239
0.9
0.9
4.8
5.1
35
7.1
8
54
63
73
2.5
2.8
7.5
7.7
266
13.2
15
248
253
258
0.8
0.9
6.2
6.4
317
3.5
5
10
41
352
3.1
3.6
9.0
9.7
268
14.9
16
259
265
272
2.4
2.7
8.4
8.6
262
12.3
14
228
245
259
0.7
1.1
5.9
6.6
243
8.2
11
147
185
192
3.0
3.3
9.6 11.0
285
13.0
14
267
268
280
1.8
3.5
7.4
9.2
285
9.9
16
287
298
309
2.4
2.7
7.8
8.2
301
11.1
12
300
304
309
2.6
2.8
7.5
7.6
299
13.8
14
293
301
303
2.4
2.9
6.6
7.4
295
13.9
16
259
290
298
3.3
3.5
8.2
8.4
301
16.3
17
293
302
313
3.4
3.8
8.3
8.5
303
15.5
18
292
303
313
28 reported exceptional surf events (Category 3) during the period of 2010 to 2012
The envelope of the reported Category 3 events was utilized to develop a relationship between
optimum wave period and wave directions for Fish Factory, Middles and Hamborg, while also
providing an estimate of the minimum required wave height to generate exceptional surfing
conditions.
The specified requirements to wind and wave conditions for Category 1, 2 and 3 wind surfing
conditions are compiled in Table 4.2. It was anticipated that the same categorization could be
applied for kitesurfing.
Windsurf definition category
Minimum Significant Wave Height [m]
Minimum Wind Speed [m/s]
Minimum Wind Direction
Maximum Wind Direction
Minimum Surf Time [hrs]
1
7.0
260
315
2
2
1.5
8.9
260
315
2
Wave Direction/Wave Period Criteria
-
-
Table 4.2
12
3
1.7
8.9
260
315
2
Inside Category3
Polygon
Wind and wave conditions for Category 1, 2 and 3 windsurfing conditions
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Potential impacts to traditional surfing at these three surf spots will only be dependent on the
potential wave sheltering and will not be affected by potential increased disturbance to the
wind. Resultantly, the surfing impact assessment based on the current three category
classifications can be considered conservative.
The conditions required for Fisherman’s Corner differ significantly from the surf spots located
east of the port. The surf spot is exclusively utilized for traditional surfing and works less
frequently than the remaining spots in the area, which made it difficult to report a track record
of historical events. As a result, only a Category 1 definition has been developed for this surf
spot, see Table 4.3.
Category
1
2
3
Minimum Offshore Significant Wave Height [m]
2.0
-
-
Minimum Wind Speed [m/s]
-
-
-
Table 4.3
Minimum Wind Direction
0
-
-
Maximum Wind Direction
50
-
-
Minimum Surf Time [hrs]
2
-
-
Wave Direction/Wave Period Criteria
-
-
-
Surf category classification (Fisherman’s Corner)
Table 4.2 and Table 4.3 definitions were applied to investigate the annual number of surfable
days based on a 33-year (1979-2012) North Sea hindcast study containing 1-hourly values of
wave and wind integral parameters. The dataset was generated by the DHI North Sea MIKE 21
SW model and extracted 1km NW from the existing harbour entrance at a water depth of 23m at
the point marked DHI buoy in Figure 4.6.
Figure 4.6
The DHI North Sea model was used to provide wind and wave data corresponding to the dates of the
reported exceptional surf days. Offshore wave data were extracted from the point marked DHI
Each time step was assessed based on the surf category definition and assigned a 1 to 3 if the
defined criteria were met. Only daylight hours occurring between 7am and 6pm were assessed.
If at least two consecutive hours in a given day satisfy any of the defined categories, the day is
considered a “surf day”. The category assigned to each respective surf day was based on the
highest category occurring for at least two consecutive hours. The results of the analysis are
presented in Section 5.1.
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4.4
MIKE 21 SW Screening Study
The MIKE 21 SW 3rd generation spectral wave model was used to carry out a screening study to
quantify the potential impact to surfing amenity due to increased wave sheltering caused by the
proposed port expansion.
The historical 1979-2012 hindcast time series of mean wave direction (MWD) and spectral peak
period (Tp) was used to create a matrix of all recorded possible combinations of MWD and Tp.
Based on a bin size resolution of 1 second by 5 degrees, the 30-year dataset yielded 368 unique
combinations of Tp and MWD. Only records with a significant wave height (H sig) of at least 1
meter were considered.
The computational mesh consisted of a total of 37,000 unstructured triangular elements. The
maximum grid resolution was 20m in the nearshore areas and in the vicinity of the harbour.
The directional resolution of the SW model was 5 degrees. A JONSVAP spectrum with an
offshore significant wave height was set to 1m for all simulations, which allowed the calculated
domain wave field to be treated as wave disturbance coefficients, without the need for further
post-processing.
The model domain for the existing port layout and the expanded port layout is presented in
Figure 4.7 and Figure 4.8. An overview of the near-field grid resolution (for the expanded port
layout) is presented in Figure 4.9.
Figure 4.7
MIKE 21 SW domain bathymetry
(current port layout)
Figure 4.8
MIKE 21 SW domain bathymetry (future port layout)
Figure 4.9
Detailed overview of nearfield domain resolution in MIKE 21 SW (proposed expanded layout)
The quasi-stationary wave response was simulated for the 368 unique combinations of offshore
Tp and MWD using the current port and the proposed port expansion.
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Subsequently, the difference in wave disturbance coefficients was evaluated inside each of the
five surf spot polygons presented in Figure 4.10. Only grid cells located at water depths greater
than 2m were taken into consideration in order to avoid differences in very shallow water.
Figure 4.10
MIKE 21 SW wave disturbance coefficient plots for current layout (left) and future layout (right) for an
offshore wave direction of 265 degrees WSW and a spectral peak period of 8s
For each wave event, a surf area was considered to experience moderate negative impact if the
average reduction in significant wave height was more than 15% but less than 50%.
If the average reduction in significant wave height was more than 50%, the surf amenity in the
particular surf spot was considered to be highly adversely impacted.
4.5
Detailed Surf Impact Study using MIKE 21 BW and OPTISURF
The wave impact screening study provided a quantification of the type and reoccurrence of surf
days, where the local wave fields were impacted by the proposed port expansion.
As defined in Section 4.4, a surf event was considered to experience a significant decrease in
surfing amenity if the average significant wave height was reduced by 50% or more caused by
the proposed port expansion. If the reduction in average significant wave height was 15% to
50%, some decrease in surfing amenity was still expected to occur. The link between a
percentage decrease in significant wave height and impact in surfing amenity was based on the
detailed investigations of two representative scenarios carried out by MIKE 21 BW and
OPTISURF.
Significant wave height is an integral parameter that is descriptive of the amount of wave energy
at each surf spot. However, in order to assess the resulting reduction of impacts in surfing
amenity, the program OPTISURF was utilized to perform this quantification through direct
analyses of the governing parameters discussed in Section 4.2.
Once the array of potential impacted events was determined, two wave scenarios were selected
to undergo detailed surfing amenity investigations. Using the non-linear Boussinesq wave
model, MIKE 21 BW, the wave transformation and detailed wave breaking patterns was
calculated in the time domain.
Subsequently, the program OPTISURF was used to calculate key surfing amenity parameters
(presented in Section 5.3) from the calculated wave field. OPTISURF utilizes the instantaneous
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wave field output to track the moving transition point between unbroken and broken waves.
Each of these points is referred to as a pocket point and marks the zone adjacent to where the
wave is breaking, which marks the optimum position for a surfer during a wave ride.
For each time step, each pocket point is tracked back to its previous position if it exists. The
vector length between the two points describes the minimum average speed the surfer would
have had to maintain in order to keep surfing the wave. If the speed exceeds 10m/s, the
particular section of the wave is considered non-surfable and the surf ride is terminated.
Subsequently a new ride is initialized for the new pocket point. A graphical output of OPTISURF
is presented in Figure 4.11. The black polygons mark the extent of the breaking wave roller,
while the red markers represent the pocket points
Figure 4.11
Example of surfing amenity analysis using OPTISURF. The black polygons mark the extent of the breaking
wave roller, while the red markers represent the pocket points
Using OPTISURF, the following surfing amenity parameters are evaluated over the course of
1 hour of wave action for respectively the current and future port layout:



Number of rideable waves
Maximum length of each surf ride
Maximum wave height of each ride
Based on the total reduction in surf rides (per hour) and the decrease of longer wave rides with
larger wave heights based on the investigated Scenario tests, it was determined that:


>50% reduction in average significant wave reduction causes the surf category of a
surfable event to be reduced to 1
15-50% reduction in average significant wave reduction causes the surf category of a
surfable event to decrease by 1.
A reduction in wave quality cannot make a surf event “non surfable”.
4.6
Wind Disturbance Analysis
The wind disturbance calculations have been performed including the disturbance of the port
expansion itself and 10 Vestas V112-3.0 Mega Watt wind turbines with a maximum height of up
to 150m. The parameterization used to asses potential impacts were selected conservatively in
order to assess the worst case impact.
The resulting change in wind conditions was investigated by DTU Vindenergi [4] using a
separate numerical wind model to quantify the impact from the wind turbines and the new port
infrastructure separately. Subsequently Grontmij A/S [2] has carried out a combined
assessment of the resulting impact in mean wind speed and turbulence level for the three surf
spots: Fish Factory, Middles and Hamborg. For each surf spot the analysed grid points we
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divided into 3 respective areas as marked by the red circles in Figure 4.12. The resultant wind
induced impact was based on the average of each grouped grid point cluster.
Investigations were carried out for U10 wind speeds ranging from 8-16m/s and wind directions
from 270 to 315 degrees. In Grontmij [2], it is reported conservatively that wind disturbances
for 7m/s winds equal to those for 8m/s, and that wind speeds larger than 16m/s equal those of
16m/s wind speeds. The disturbance of winds coming from more than 315 degrees north is
considered negligible. The natural background turbulence TI was set to 6% (Grontmij [2]) ,
which compares to open water. As wind conditions during surfable conditions are experiencing
some influence from the existing port, the selected TI is considered conservative. A definition of
TI values associated with different types of terrain roughness is given in Table 4.4 below
Terrain
Roughness Class
TI(%)
Open Water
0.0
6
Open terrain – few buildings
and trees, low hills
1.0
10
Built up terrain – several
buildings and trees
2.0
15
Cities, suburban areas, forest,
undulating terrain
3.0
20
Table 4.4
Definition of turbulence index for different types of terrain roughness (Translated from Grontmij [2])
For each wind scenario, the following three parameters were evaluated:



Reduction of mean wind speed (Um)
Increase in turbulence (TI)
The number of occurrences, where the wind speed deviates more than 2m/s from the
mean wind speed during 30 minutes (N)
The approximate height of a windsurfers sail is 4.5m, while a kitesurfers kite can obtain heights
above 20m. Resultantly, the two types of surfers will potentially be affected differently.
As a result, the representative wind impact for windsurfers and kitesurfers has been based on
values extracted at respectively10m DVR90 for windsurfers and 20m for kitesurfers. The grid
extraction points used for the analysis are presented in Figure 4.12.
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Figure 4.12
Google Earth overview of proposed port expansion and the 6 points used for assessing the combined wind
impact at Fish Factory, Middles and Hamborg
As described in Section 4.2 the increase in wind turbulence and cyclic deviation from mean
values can cause a reduction of wind and kitesurfing amenity. The key assumption is that an
increase in TI and N compared to values occurring during current wind conditions will
potentially result in an impact on wind and kitesurfing amenity. During current conditions N
varies with wind speed and direction as illustrated in Table 4.5. The upper and lower limit for
each wind speed is defined by Nmin and Nmax. The potential impact on surfing amenity was based
on relating the N values for the new layout compared to the corresponding N min and Nmax.
Mean wind speed
(m/s)
Nmin
[number of
occurrences]
Nmax
[number of
occurrences]
8
4
8
10
8
12
12
12
16
14
16
20
16
20
24
Table 4.5
Threshold values for N during different mean wind speeds (30 minute duration)
Based on the wind impact analysis, Grontmij adopted the following relationship between N, TI
and the decline in wind and kitesurfing amenity.
1. If N < Nmin no change to the surfing amenity category will occur.
2. Nmin<N <Nmax is considered to cause a potential change in wind conditions resulting the
surfing amenity category to be reduced by 1. As an example, an impacted Category 3 event
(exceptional surf day) will be reduced to a Category 2 (good surf day). The surf event
cannot become “non surfable”, hence the minimum category will always be Category 1.
3. Nmax < N is considered to cause a potential significant change in wind conditions resulting
the surfing amenity category to be reduced to 1.
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4. If TI is increased to more than 12%, it will result in the surf amenity category to be reduced
to Category 1.
5. If the decrease in U10 or U20 causes the mean wind speed to be reduced to less than 8.9 m/s
but more than 7m/s, the surfing amenity category will be reduced to Category 1.
6. If the decrease in U10 or U20 causes the mean wind speed to be reduced to less than 7 m/s,
the surf event is considered “non surfable”.
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5
Wave-induced Surf Amenity Impact – Results
The results determined, based on the methodology described in Section 4, are presented in the
following.
5.1
Site-specific Surfing Amenity Classification. Existing Conditions
Below is listed the total amount of surfable days is presented for Fisherman’s Corner, Fish
Factory, Middles and Hamborg based on the criteria specified in Section 4.3.
The average, maximum and minimum number of surfable days per year for Fish Factory,
Middles and Hamborg is listed in Table 5.1 and Figure 5.1. The annual distribution of surfable
days is presented in Figure 5.2.
Surfable Days
Category 1
Category 2
Category 3
Yearly Average
29
24
23
Yearly Minimum
8
8
12
Yearly Maximum
38
44
43
Table 5.1
Number of surfable days per year – Fakir, Fish Factory, Middles and Hamborg
Figure 5.1
Average number of windsurf/kitesurf days per year for Fakir, Fish Factory, Middles and Hamborg (Current
Layout)
Figure 5.2
Total number of windsurf/kitesurf days per year based on category (1979- March 2012) for Fish Factory,
Fakir, Middles and Hamborg (Current Layout)
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For the surf spots Fakir, Fish Factory, Middles and Hamborg, the average amount of surfable
days per year is 76 corresponding to approximately 1.5 surfable days per week. 30% of all days
are classified as exceptional events (Category 3).
The average, maximum and minimum number of surfable days per year for Fisherman’s
Corner is listed in Table 5.2. The annual distribution of surfable days is presented in Figure 5.3.
Surfable Days
Category 1
Category 2
Category 3
Yearly Average
4
0
0
Yearly Minimum
0
0
0
Yearly Maximum
13
0
0
Table 5.2
Number of surfable days per year – Fisherman’s Corner
Figure 5.3
Total number of traditional surf days per year based on category (1979-2012) for Fisherman’s Corner
(Current Layout)
Fisherman’s Corner is only utilized by traditional style surfers and does not provide suitable
conditions as often as the surf spots east of the Port. The average number of surf days is only
4 days per year.
5.2
MIKE 21 SW Screening Study
5.2.1
General
The following figures present the distribution of Category 1, 2 and 3 surfable events arranged
based on their combinations of wave direction and wave period. For each surf spot, the colourcoded contour plot illustrates the distribution of all surfable events from Category 1 and above.
The reported exceptional surf conditions (Category 3) reported for Middles are considered
representative for Hamborg and Fish Factory. In each of their respective plots, the Category 3
events are plotted as black dots. In each plot, their distribution has been used to define a
polygon in which the combinations of MWD and Tp all provide Category 3 surf conditions given
that the requirements to minimum wave height, wind speed and wind window are also satisfied.
The Category 3 polygon has been enclosed by a white outline.
Outside the Category 3 polygon, a larger polygon marked by a dashed white line outlines the
MWD/Tp combinations associated with the good surfing conditions defined by Category 2.
The matrix consisting of wave direction and wave period combinations used in the assessment
is illustrated by the grey area. Combinations resulting in a wave height decrease of more than
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11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
50% are highlighted by a red outline, which indicates that the event is potentially significantly
impacted due to disturbance of the wave field caused by the proposed port expansion.
Combinations resulting in a wave height decrease of 15% to 50% are highlighted by a black
outline, which indicates that the event is potentially impacted due to disturbance of the wave
field caused by the proposed port expansion.
5.2.2
Fish Factory
Fish Factory is the surf spot located in the closest proximity east of the proposed port
expansion. As a result, it is to be expected that the wave sheltering impact will be the greatest at
this location. Figure 5.4 illustrates how the proposed port expansion results in a significant
amount of the surfable events to be impacted by increased wave sheltering causing decreased
wave heights at the location. It is illustrated how impacted surf conditions are with mean
offshore directions of 285oN to 300oN. Events containing larger wave periods increase the
amount of refraction and diffraction occurring around the Hanstholm headland and proposed
port expansion. Resultantly, the wave penetration into the Fish Factory, Middles and Hamborg
for events with a high spectral peak period is less affected by the new layout compared to events
with a small spectral peak period.
It is noticed that all surfable events are expected to experience some level of decrease in surfing
amenity. The total amount of surfable events experiencing a significant decline in surfing
amenity (due to a 50% or higher decline in significant wave height) is 49.7%.
Figure 5.4
Wave-induced impact at Fish Factory. For explanation see Section 5.2.1
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5.2.3
Middles
The surf spot Middles is located further east of Fish Factory and therefore the wave sheltering
and associated wave impact caused by the proposed port expansion is less, as shown in Figure
5.5. The total amount of surfable events potentially affected by the increased wave sheltering is
23.1%. Only a smaller proportion of Category 3 type events are expected to be affected. The
total amount of surfable events significantly affected is 8.5%. Most of the significantly affected
events are Category 1 with only a few Category 2 affected. No Category 3 events are expected to
be significantly affected.
Figure 5.5
24
Wave-induced impact at Middles. For explanation see Section 5.2.1
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5.2.4
Hamborg
Hamborg is the surf spot most to the east and furthest away from the proposed port expansion.
Resultantly, the induced wave sheltering and associated wave impact caused by the proposed
port expansion is the smallest of the three eastern surf spots as shown in Figure 5.6. The
amount of surfable events potentially affected by the increased wave sheltering is 9.8%. The
amount of surfable events significantly affected by the increased wave sheltering is 3.1%.
Only Category 1 and Category 2 type events are expected to be affected.
Figure 5.6
Wave-induced impact at Hamborg. For explanation see Section 5.2.1
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5.2.5
Fisherman’s Corner
Figure 5.7 illustrates the potential impact on surfing conditions based on the proposed port
expansion. It is observed that only waves with a direction of 50-65 degrees and a wave peak
period of less than 5s will potentially be affected. It is observed that this narrow window of
impact is far away from the envelope of surfable conditions. Resultantly, it can be concluded
that no impact on Fisherman’s Corner is to be expected.
Figure 5.7
5.3
Wave-induced impact on Fisherman’s Corner. It is observed that the port expansion causes no impact on
the surf amenity at this surf spot
Detailed Surf Impact Study using MIKE 21 BW and OPTISURF
Based on the SW wave impact screening study, the two following wave scenarios were selected
to represent the expected reduction in surfing amenity following the predicted wave height
reduction.
Table 5.3 lists the two scenarios selected for detailed investigations of surf amenity impact using
MIKE 21 BW and OPTISURF. The second column lists the mean offshore wave direction applied
in MIKE 21 SW, which refers to the values on the y-axis in the wave impact figures. The third
column lists the corresponding mean wave direction at the DHI location (Figure 4.6), which is
used as offshore boundary condition for the MIKE 21 BW model.
Scenario 1
Scenario 2
Table 5.3
26
Mean wave direction
at
SW offshore boundary
265
285
Mean wave direction
at
BW offshore boundary
273
286
Spectral peak
period
Offshore significant
wave height
8.3s
6.2s
2.5m
1.7m
Scenario 1 and Scenario 2 were used to provide a detailed investigation of the wave-induced impact on
surfing amenity using MIKE 21 BW and OPTISURF
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Scenario 1 was selected to provide a conservative prediction of the decrease in surfing amenity
for Category 3 surf events due to the increased wave sheltering surf events. The offshore
significant wave height of 2.5m was selected so that Scenario 1 compares to the historical
Category 3 event that took place 27 January 2011 as presented in Table 4.1.
Scenario 2 was selected to provide a conservative prediction of the decrease in surfing amenity
for Category 2 surf events due to the increased wave sheltering surf events. The wave height for
this scenario was set to 1.7m, which equals the mean wave height for all potentially impacted
Category 2 events at Middles. The location of simulations 1 and 2 compared to the potential
wave induced impact for Fish Factory, Middles and Hamborg is presented in Figure 5.8 through
Figure 5.10.
Figure 5.8
Wave-induced impact on Fish Factory. Scenario 1 and Scenario 2 were selected to provide a
conservative estimate of the reduction in wave-induced surf amenity
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28
Figure 5.9
Wave-induced impact on Middles. Scenario 1 and Scenario 2 were selected to provide a conservative
estimate of the reduction in wave-induced surf amenity
Figure 5.10
Wave-induced impact on Hamborg. Scenario 1 and Scenario 2 were selected to provide a conservative
estimate of the reduction in wave-induced surf amenity
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
5.3.1
Scenario 1
Figure 5.11 illustrates the difference in significant wave height for Scenario 1. It is noticed that
Fish Factory experiences a level of local wave focusing immediately east of the Roshage pier
caused by local sand bars. For scenario 1, it is illustrated how the future layout will cause
significant wave sheltering in a zone extending east from Fish Factory towards Middles and
Hamborg.
Figure 5.11
Scenario 1. Significant wave height plots produced by MIKE21 BW for current (left) and future (right) port
layout
Figure 5.12 and Figure 5.13 illustrate the Scenario 1 possible surf rides during 1 hour for
respectively current and future port layout. Each line represents the trajectory path of each
ride. The path length equals the surf ride length. The coloration of each ride represents the
maximum wave face height at the position of the surfer during the ride.
Figure 5.12
Current Layout – Scenario 1. Possible surf rides during 1 hour. Each line represents the trajectory path of a
ride. The coloration of each ride represents the maximum wave face height at the position of the surfer
during the ride
Figure 5.13
Future Layout – Scenario 1. Possible surf rides during 1 hour. Each line represents the trajectory path of a
ride. The coloration of each ride represents the maximum wave face height at the position of the surfer
during the ride
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Fish Factory
The MIKE 21 SW screening study predicted a Scenario 1 average wave height reduction for Fish
Factory of more than 50%. Using OPTISURF, it is noticed from Table 5.4 and Table 5.5 that Fish
Factory experiences a reduction in total number of surfable rides of more than 86% due to the
future port layout. In addition, almost all surfable rides with wave heights of more than 1.5m
and ride lengths of more than 200m have been eliminated.
0.5-1m
1-1.5m
1.5-2m
2-2.5m
0.5-1m
1-1.5m
1.5-2m
2-2.5m
10-50m
2611
792
90
1
10-50m
439
45
0
0
50-100m
1180
1028
118
2
50-100m
235
105
0
0
100-150m
212
628
64
2
100-150m
32
79
1
0
150-200m
18
179
68
0
150-200m
5
22
0
0
200-250m
4
21
14
3
200-250m
0
1
1
0
250-300m
0
10
9
0
250-300m
0
0
0
0
300-350m
0
3
0
0
300-350m
0
0
0
0
350-400m
0
2
1
0
350-400m
0
0
0
0
Total Number of Rides : 7060
Table 5.4
Total Number of Rides : 965
Number of surfable rides/hour for Fish Factory
(Current Layout)
Table 5.5
Number of surfable rides/hour for Fish Factory (Future
Layout)
Due to the significant reduction in the size, length and frequency of rideable waves it was
determined that the resulting reduction in surf amenity would result in the surf category to be
reduced to 1.
Middles
The MIKE21 SW screening study predicted an average wave height reduction for Middles
Scenario 1 of 15% to 50%. Using OPTISURF it is noticed from Table 5.6 and Table 5.7 that
Middles experiences a reduction in total number of surfable rides of 35% due to the future port
layout. In addition a significant reduction in surfable rides with wave heights of more than 1.5m
and ride lengths of more than 150m is noticed.
0.5-1m
1-1.5m
1.5-2m
2-2.5m
0.5-1m
1-1.5m
1.5-2m
2-2.5m
10-50m
2892
512
11
0
10-50m
1905
248
2
0
50-100m
1499
537
9
0
50-100m
1104
323
5
0
100-150m
226
642
10
0
100-150m
173
358
7
0
150-200m
13
108
13
0
150-200m
6
63
2
0
200-250m
0
5
2
0
200-250m
2
1
0
0
Total Number of Rides : 6479
Table 5.6
Number of surfable rides/hour for Middles (Current
Layout)
Total Number of Rides : 4199
Table 5.7
Number of surfable rides/hour for Middles (Future
Layout)
The proposed port layout will cause a noticeable reduction in the quality of surfable waves, but
it does not demise it to the same level as what is experienced with Fish Factory. As a result, it
was determined that due to the reduction in the size, length and frequency of rideable waves,
the resulting reduction in surf amenity would result in the surf category to be reduced by 1.
Hamborg
The MIKE 21 SW screening study predicted a Scenario 1 average wave height reduction for
Hamborg of 15% to 50%, being located just inside the rim of the 15% impact threshold. Using
OPTISURF, it is seen from Table 5.8 and Table 5.9 that Hamborg experiences a reduction in total
number of surfable rides of 22% due to the future port layout. A similar reduction is
experienced for the wave rides of more than 1.5m wave height and 150m ride length.
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11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
0.5-1m
1-1.5m
1.5-2m
2-2.5m
0.5-1m
1-1.5m
1.5-2m
2-2.5m
10-50m
3439
751
15
0
10-50m
2611
515
12
0
50-100m
1218
773
15
0
50-100m
1064
570
4
0
100-150m
192
734
9
0
100-150m
153
609
7
0
150-200m
12
107
8
0
150-200m
11
81
7
0
200-250m
2
7
1
0
200-250m
0
5
1
250-300m
0
0
0
0
250-300m
0
0
0
0
300-350m
0
0
0
0
300-350m
1
1
0
0
Total Number of Rides : 7284
Table 5.8
Number of surfable rides/hour for Hamborg
(Current Layout)
Total Number of Rides : 5652
Table 5.9
Number of surfable rides/hour for Hamborg (Future
Layout)
The proposed port layout will only cause minor reduction in the total number of surfable rides
for Hamborg. However, from Table 5.9, it is noticed how the proportion of wave rides with
wave heights above 1.5m and lengths of more than 50m decreases by more than 35%.
As a result, it was determined that due to the reduction in the size, length and frequency of
rideable waves at Hamborg the resulting reduction in surf amenity would result in the surf
category to be reduced by 1.
5.3.2
Scenario 2
Figure 5.14 illustrates the difference in significant wave height for Scenario 2. As with
Scenario 1, it is noticed that Fish Factory experiences some local waves focusing immediately
east of the Roshage pier. It is illustrated how the future layout causes wave sheltering in a zone
extending east from Fish Factory towards Middles and Hamborg.
Figure 5.14
Scenario 2. Significant wave height plots produced by MIKE 21 BW for current (left) and future (right) port
layout
From Figure 5.15 and Figure 5.16, it is noticed how the proposed port expansion will result in a
strong decrease in surfable waves for Fish Factory, and to a lesser degree also for Middles and
Hamborg.
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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Figure 5.15
Current Layout – Scenario 2. Each line represents the trajectory path of a ride. The coloration of each ride
represents the maximum wave face height at the position of the surfer during the ride
Figure 5.16
Future Layout – Scenario 2. Each line represents the trajectory path of a ride. The coloration of each ride
represents the maximum wave face height at the position of the surfer during the ride
Fish Factory
For Scenario 2, the MIKE 21 SW screening study predicted an average wave height reduction for
Fish Factory at the location of significantly more than 50%. From the OPTISURF simulations, it
is noticed from Table 5.10 and Table 5.11 that Fish Factory experiences almost a complete
disintegration of surfable rides due to the future port layout.
0.5-1m
1-1.5m
1.5-2m
2-2.5m
0.5-1m
1-1.5m
1.5-2m
2-2.5m
10-50m
854
54
0
0
10-50m
18
1
0
0
50-100m
547
79
0
0
50-100m
7
2
0
0
100-150m
128
107
0
0
100-150m
0
1
0
0
150-200m
10
22
0
0
150-200m
0
0
0
0
200-250m
2
1
0
0
Total Number of Rides : 1804
Table 5.10
Number of surfable rides/hour for Fish Factory
Scenario 2 (Current Layout)
Total Number of Rides : 29
Table 5.11
Number of surfable rides/hour for Fish Factory
Scenario 2 (Future Layout)
Due to the significant reduction in the size, length and frequency of rideable waves, it was
determined that the resulting reduction in surf amenity would result in the surf category to be
reduced to 1.
Middles
For Scenario 2, the MIKE 21 SW screening study predicted an average wave height reduction for
Middles at the location of 15% - 50%. OPTISURF simulations calculated the amount of surfable
rides to be reduced by 26% due to the future port layout based on Table 5.12 and Table 5.13
results. The proportion of waves above 1 and rides longer than 50m are small and largely
unaffected.
32
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
0.5-1m
1-1.5m
1.5-2m
2-2.5m
0.5-1m
1-1.5m
1.5-2m
2-2.5m
10-50m
88
2
0
0
10-50m
57
4
0
0
50-100m
24
5
0
0
50-100m
22
4
0
0
100-150m
2
0
0
0
100-150m
0
2
0
0
150-200m
0
0
0
0
150-200m
0
0
0
0
Total Number of Rides : 121
Table 5.12
Total Number of Rides : 89
Number of surfable rides/hour for Middles Scenario 2
(Current Layout)
Table 5.13
Number of surfable rides/hour for Middles Scenario 2
(Future Layout)
As a result, the reduction in frequency of rideable waves the resulting reduction in surf amenity
would result in the surf category to be reduced by 1.
Hamborg
For Scenario 2, the MIKE 21 SW screening study predicted an average wave height reduction for
Hamborg at the location of 15% - 50%. OPTISURF simulations calculated the amount of surfable
rides to be reduced by 40% due to the future port layout as presented in Table 5.14 and Table
5.15. The proportion of rides with wave heights above 1m is small and largely unaffected.
0.5-1m
1-1.5m
1.5-2m
2-2.5m
0.5-1m
1-1.5m
1.5-2m
2-2.5m
10-50m
140
4
0
0
10-50m
79
1
0
0
50-100m
39
0
0
0
50-100m
25
2
0
0
100-150m
3
0
0
0
100-150m
5
0
0
0
150-200m
1
0
0
0
150-200m
0
0
0
0
Total Number of Rides : 187
Table 5.14
Number of surfable rides/hour for Hamborg
Scenario 2 (Current Layout)
Total Number of Rides : 112
Table 5.15
Number of surfable rides/hour for Hamborg Scenario 2
(Future Layout)
As a result, the reduction in frequency of rideable waves the resulting reduction in surf amenity
would result in the surf category to be reduced by 1.
5.4
Wave-induced Surf Amenity Impact
This section presents the predicted surf amenity impact only due to the changes in local wave
conditions caused by the future port expansion. The quantification of impacted events is
provided by the MIKE 21 SW screening study, while the resulting reduction in surf category is
based on the Scenario 1 and Scenario 2 OPTISURF investigations.
The MIKE 21 SW screening study confirmed that the surfing amenity at Fisherman’s Corner will
not be affected. Hence, only results for Fish Factory, Middles and Hamborg are presented below.
5.4.1
Fish Factory
From model investigations presented in Table 5.16 and Figure 5.17 through Figure 5.21, it is
demonstrated that the proposed port expansion will cause a significant reduction of exceptional
(Category 3) surf days at Fish Factory due to increased wave sheltering and reduced wave
heights during westerly wave directions. Category 2 surf days will be reduced by 33%.
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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Wave Impact
34
Category 1
Category 2
Category 3
Current
Future
Current
Future
Current
Future
Yearly Average
29
60
24
16
23
0
Yearly Minimum
8
27
8
6
12
0
Yearly Maximum
38
86
44
33
43
0
Table 5.16
Wave-induced impact to surfing amenity at Fish Factory
Figure 5.17
Average distribution of windsurf days – Current
Layout (Fish Factory)
Figure 5.19
Yearly distribution of windsurf days – Wave impact – Category 1 (Fish Factory)
Figure 5.20
Yearly distribution of windsurf days – Wave impact – Category 2 (Fish Factory)
Figure 5.18
Average distribution of windsurf days –
Future Layout. Wave Impact only (Fish
Factory)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 5.21
5.4.2
Yearly distribution of windsurf days – Wave impact – Category 3 (Fish Factory)
Middles
From model investigations presented in Table 5.17 and Figure 5.22 through Figure 5.26, it is
demonstrated that the proposed port expansion will have almost no impact to exceptional
(Category 3) surf days at Middles with an average reduction of only 1 day per year. Category 2
surf days will be reduced by 25%.
Wave Impact
Category 2
Category 3
Current
Future
Current
Future
Current
Future
Yearly Average
29
36
24
18
23
22
Yearly Minimum
8
10
8
5
12
11
Yearly Maximum
38
48
44
34
43
42
Table 5.17
Figure 5.22
Figure 5.24
Category 1
Wave-induced impact to surfing amenity at Middles
Average distribution of windsurf days –
Current Layout (Middles)
Figure 5.23
Average distribution of windsurf days –
Future Layout. Wave Impact only (Middles)
Yearly distribution of windsurf days – Wave impact – Category 1 (Middles)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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5.4.3
Figure 5.25
Yearly distribution of windsurf days – Wave impact – Category 2 (Middles)
Figure 5.26
Yearly distribution of windsurf days – Wave impact – Category 3 (Middles)
Hamborg
From model investigations presented in Table 5.18 and Figure 5.27 through Figure 5.31, it is
demonstrated that the proposed port expansion will have almost no impact to the number of
surf days at Hamborg. The number of Category 2 events is only reduced by 1 day per year.
No impact is seen for Category 3 events.
Wave Impact
Yearly Average
Category 2
Category 3
Future
Current
Future
Current
Future
29
31
24
23
23
23
Yearly Minimum
8
9
8
9
12
12
Yearly Maximum
38
40
44
41
43
43
Table 5.18
Figure 5.27
36
Category 1
Current
Wave-induced impact to surfing amenity at Hamborg
Average distribution of windsurf days –
Current Layout (Hamborg)
Figure 5.28
Average distribution of windsurf days – Future
Layout. Wave Impact only (Hamborg)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 5.29
Yearly distribution of windsurf days – Wave impact – Category 1 (Hamborg)
Figure 5.30
Yearly distribution of windsurf days – Wave impact – Category 2 (Hamborg)
Figure 5.31
Yearly distribution of windsurf days – Wave impact – Category 3 (Hamborg)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
37
6
Wind-induced Surf Amenity Impact - Results
This section presents the predicted surf amenity impact due to the estimated changes in local
wind conditions caused by the future port expansion. The quantification of impacted events and
the resulting reduction in surf category is based on the methodology presented in Section 4.6
and is based on a worst case assumption.
6.1
Fish Factory
Based on the wind-induced surf amenity impact criteria defined in Section 4.6, the resulting
reduction was calculated based on the 1 January 1979 to 4 April 2012 wave and wind hind cast
dataset. Fisherman’s Corner is only utilized for traditional style surfing; hence, the surfing
amenity is not negatively impacted due to potential reduction in wind speed and increased
turbulence and hence only the wind-induced surf amenity impact at Fish Factory, Middles and
Hamborg was assessed.
For Fish Factory, the increase in wind-induced turbulence TI and wind gustiness N% due to the
proposed port expansion will cause a significant reduction in the surfing ranking category as
illustrated in Table 6.1 and Table 6.2 and Figure 6.1 through Figure 6.10. Virtually, all
Category 3 conditions have been eliminated, while Category 2 conditions have been reduced by
88%. The yearly average amount of total surfable days is reduced by 20%.
Wind Impact
Table 6.1
Category 1
Current
Future
Category 2
Current
Future
Category 3
Current
Future
Yearly Average
29
58
24
3
23
0
Yearly Minimum
8
29
8
0
12
0
Yearly Maximum
38
95
44
7
43
1
Wind-induced impact to surfing amenity at Fish Factory (Windsurfing)
Wind Impact
Category 1
Current
Future
Category 2
Current
Future
Category 3
Current
Future
Yearly Average
29
58
24
3
23
0
Yearly Minimum
8
28
8
0
12
0
Yearly Maximum
38
94
44
7
43
1
Table 6.2
Wind-induced impact to surfing amenity at Fish Factory (Kitesurfing)
Figure 6.1
Average distribution of windsurf days –
Current Layout (Fish Factory)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 6.2
Average distribution of windsurf days –
Future Layout (Fish Factory)
39
DHI
40
Figure 6.4
Average distribution of Kitesurf days – Future
Layout – Kite impact only (Fish Factory)
Figure 6.3
Average distribution of Kitesurf days –
Current Layout (Fish Factory)
Figure 6.5
Yearly distribution of windsurf days – Wind impact – Category 1 (Fish Factory)
Figure 6.6
Yearly distribution of Kitesurf days – Wind impact – Category 1 (Fish Factory)
Figure 6.7
Yearly distribution of windsurf days – Wind impact – Category 2 (Fish Factory)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
6.2
Figure 6.8
Yearly distribution of kitesurf days – Wind impact – Category 2 (Fish Factory)
Figure 6.9
Yearly distribution of windsurf days – Wind impact – Category 3 (Fish Factory)
Figure 6.10
Yearly distribution of kitesurf days – Wind impact – Category 3 (Fish Factory)
Middles
For Middles, the increase in wind-induced turbulence TI and wind gustiness N% is less
compared to Fish Factory, due to its location further away from the proposed port expansion, as
illustrated in Table 6.3 and Table 6.4 and Figure 6.11 through Figure 6.20. The amount of
Category 3 conditions has been reduced by 22% for windsurfing and 17% for Kitesurfing.
Category 2 conditions have been reduced by 8% for Windsurfing and 17 for Kitesurfing. The
yearly average amount of total surfable days has been reduced by 9% for Windsurfing and 12%
for Kitesurfing.
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Category 1
Wind Impact
Current
Future
Current
Future
Category 3
Current
Future
Yearly Average
29
29
24
22
23
18
Yearly Minimum
8
8
8
6
12
9
Yearly Maximum
38
38
44
43
43
36
Table 6.3
Wind-induced impact to surfing amenity at Middles (Windsurfing)
Category 1
Wind Impact
Current
Category 2
Future
Current
Future
Category 3
Current
Future
Yearly Average
29
28
24
20
23
19
Yearly Minimum
8
9
8
4
12
8
Yearly Maximum
38
40
44
38
43
38
Table 6.4
Wind-induced impact to surfing amenity at Middles (Kitesurfing)
Figure 6.11
Average distribution of windsurf days –
Current Layout (Middles)
Figure 6.12
Average distribution of windsurf days – Future
Layout – Wind impact only (Middles)
Figure 6.13
Average distribution of kitesurf days –
Current Layout (Middles)
Figure 6.14
Average distribution of kitesurf days –
Future Layout – Kite impact only (Middles)
Figure 6.15
42
Category 2
Yearly distribution of windsurf days – Wind impact – Category 1 (Middles)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 6.16
Yearly distribution of kitesurf days – Wind impact – Category 1 (Middles)
Figure 6.17
Yearly distribution of windsurf days – Wind impact – Category 2 (Middles)
Figure 6.18
Yearly distribution of kitesurf days – Wind impact – Category 2 (Middles)
Figure 6.19
Yearly distribution of windsurf days – Wind impact – Category 3 (Middles)
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Figure 6.20
6.3
Yearly distribution of kitesurf days – Wind impact – Category 3 (Middles)
Hamborg
For Hamborg, the wind-induced impact to surfing amenity will be the smallest of the three
easterly surf spots as illustrated in Table 6.5 and Table 6.6 and Figure 6.21 through Figure 6.30.
The amount of Category 3 conditions has decreased by 9% for both windsurfing and kitesurfing,
while Category 2 conditions have been reduced by 8%. The yearly average amount of total
surfable days is reduced by 6% for windsurfing and 7% for kitesurfing.
Category 1
Wind Impact
Current
Current
Future
Category 3
Current
Future
Yearly Average
29
29
24
22
23
21
Yearly Minimum
8
9
8
6
12
10
Yearly Maximum
38
40
44
41
43
41
Table 6.5
Wind-induced impact to surfing amenity at Hamborg (Windsurfing)
Category 1
Wind Impact
Current
Category 2
Future
Current
Future
Category 3
Current
Future
Yearly Average
29
28
24
22
23
21
Yearly Minimum
8
9
8
6
12
9
Yearly Maximum
38
39
44
41
43
41
Table 6.6
Wind-induced impact to surfing amenity at Hamborg (Kitesurfing)
Figure 6.21
44
Category 2
Future
Average distribution of windsurf days –
Current Layout (Hamborg)
Figure 6.22
Average distribution of windsurf days –
Future Layout – Wind impact only
(Hamborg)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 6.23
Average distribution of kitesurf days –
Current Layout (Hamborg)
Figure 6.24
Average distribution of kitesurf days –
Future Layout – Kite impact only
(Hamborg)
Figure 6.25
Yearly distribution of windsurf days – Wind impact – Category 1 (Hamborg)
Figure 6.26
Yearly distribution of kitesurf days – Wind impact – Category 1 (Hamborg)
Figure 6.27
Yearly distribution of windsurf days – Wind impact – Category 2 (Hamborg)
Figure 6.28
Yearly distribution of kitesurf days – Wind impact – Category 2 (Hamborg)
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45
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46
Figure 6.29
Yearly distribution of windsurf days – Wind impact – Category 3 (Hamborg)
Figure 6.30
Yearly distribution of kitesurf days – Wind impact – Category 3 (Hamborg)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
7
Combined Surf Amenity Impact – Conclusions
This section presents the predicted surf amenity impact only due to the combined changes in
local wind and wave conditions caused by the future port expansion. In this assessment each
surfable event is evaluated against the combined surf quality impact imposed by wave and wind
induced impacts as presented separately in Section 5 and Section 6.
7.1
Fish Factory
The results of the combined assessment for Fish Factory are presented in Table 7.1 and Table
7.2 and Figure 7.1 through Figure 7.10.
Category 1
Combined Impact
Current
Category 2
Future
Current
Category 3
Future
Current
Future
Yearly Average
29
62
24
0
23
0
Yearly Minimum
8
33
8
0
12
0
Yearly Maximum
38
100
44
2
43
0
Table 7.1
Combined impact to surfing amenity at Fish Factory (Windsurfing)
Category 1
Combined Impact
Current
Category 2
Future
Current
Category 3
Future
Current
Future
Yearly Average
29
61
24
0
23
0
Yearly Minimum
8
32
8
0
12
0
Yearly Maximum
38
99
44
2
43
0
Table 7.2
Combined impact to surfing amenity at Fish Factory (Kitesurfing)
Figure 7.1
Average distribution of windsurf days – Current
Layout (Fish Factory)
Figure 7.2
Average distribution of windsurf days –
Future Layout – Total impact (Fish Factory)
Figure 7.3
Average distribution of kitesurf days – Current
Layout (Fish Factory)
Figure 7.4
Average distribution of kitesurf days – Future
Layout – Total impact (Fish Factory)
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48
Figure 7.5
Yearly distribution of windsurf days – Total impact – Category 1 (Fish Factory)
Figure 7.6
Yearly distribution of kitesurf days – Total impact – Category 1 (Fish Factory)
Figure 7.7
Yearly distribution of windsurf days – Total impact – Category 2 (Fish Factory)
Figure 7.8
Yearly distribution of kitesurf days – Total impact – Category 2 (Fish Factory)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 7.9
Yearly distribution of windsurf days – Total impact – Category 3 (Fish Factory)
Figure 7.10
Yearly distribution of kitesurf days – Total impact – Category 3 (Fish Factory)
From the assessment of the combined wind and current impact to surf amenity, it is
demonstrated that the proposed port expansion will cause an elimination of exceptional
(Category 3) and good (Category 2) surf days at Fish Factory. The total amount of surfable days
is reduced by 18% for windsurfing and 19% for kitesurfing due to increased wind sheltering.
7.2
Middles
The results of the combined assessment for Middles are presented in Table 7.3 and Table 7.4
and Figure 7.11 through Figure 7.20.
Category 1
Combined Impact
Current
Category 2
Future
Current
Future
Category 3
Current
Future
Yearly Average
29
33
24
18
23
17
Yearly Minimum
8
9
8
5
12
8
Yearly Maximum
38
48
44
33
43
35
Table 7.3
Combined impact to surfing amenity at Middles (Windsurfing)
Category 1
Combined Impact
Current
Category 2
Future
Current
Future
Category 3
Current
Future
Yearly Average
29
33
24
16
23
18
Yearly Minimum
8
10
8
4
12
8
Yearly Maximum
38
46
44
29
43
37
Table 7.4
Combined impact to surfing amenity at Middles (Kitesurfing)
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50
Figure 7.12
Average distribution of windsurf days – Future
Layout – Total impact (Middles)
Figure 7.11
Average distribution of windsurf days
– Current Layout (Middles)
Figure 7.13
Average distribution of kitesurf days –
Current Layout (Middles)
Figure 7.15
Yearly distribution of windsurf days – Total impact – Category 1 (Middles)
Figure 7.16
Yearly distribution of kitesurf days – Total impact – Category 1 (Middles)
Figure 7.14
Average distribution of kitesurf days – Future
Layout – Total impact (Middles)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 7.17
Yearly distribution of windsurf days – Total impact – Category 2 (Middles)
Figure 7.18
Yearly distribution of kitesurf days – Total impact – Category 2 (Middles)
Figure 7.19
Yearly distribution of windsurf days – Total impact – Category 3 (Middles)
Figure 7.20
Yearly distribution of kitesurf days – Total impact – Category 3 (Middles)
From the assessment of the combined wind and current impact to surf amenity, it is
demonstrated that the proposed port expansion will cause a reduction of exceptional
surf days (Category 3) of 26% at Middles for windsurfing and 22% for kitesurfing.
The decrease is caused mostly due to increased wind turbulence and gustiness caused
by the wind turbines and proposed port layout. The reduction in Category 2 surf days
is respectively 25% and 33% for wind surfing and kitesurfing.
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
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The total amount of surfable days is reduced by 11% for windsurfing and 12% for kitesurfing
due to increased wind sheltering.
7.3
Hamborg
The results of the combined assessment for Hamborg are presented in Table 7.5 and Table 7.6
and Figure 7.21 through Figure 7.30.
Category 1
Combined Impact
Current
Current
Future
Category 3
Current
Future
Yearly Average
29
30
24
21
23
21
Yearly Minimum
8
9
8
7
12
10
Yearly Maximum
38
41
44
38
43
41
Table 7.5
Combined impact to surfing amenity at Hamborg (Windsurfing)
Category 1
Combined Impact
52
Category 2
Future
Current
Category 2
Future
Current
Future
Category 3
Current
Future
Yearly Average
29
29
24
21
23
21
Yearly Minimum
8
9
8
7
12
9
Yearly Maximum
38
40
44
38
43
41
Table 7.6
Combined impact to surfing amenity at Hamborg (Kitesurfing)
Figure 7.21
Average distribution of windsurf days –
Current Layout (Hamborg)
Figure 7.22
Average distribution of windsurf days – Future
Layout – Total impact (Hamborg)
Figure 7.23
Average distribution of kitesurf days –
Current Layout (Hamborg)
Figure 7.24
Average distribution of kitesurf days – Future
Layout – Total impact (Hamborg)
11810435-2 Hanstholm SurfAmenityImpactAssessment/sbm/prs/ybr-hec/pot – 09/12
Figure 7.25
Yearly distribution of windsurf days – Total impact – Category 1 (Hamborg)
Figure 7.26
Yearly distribution of kitesurf days – Total impact – Category 1 (Hamborg)
Figure 7.27
Yearly distribution of windsurf days – Total impact – Category 2 (Hamborg)
Figure 7.28
Yearly distribution of kitesurf days – Total impact – Category 2 (Hamborg)
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Figure 7.29
Yearly distribution of windsurf days – Total impact – Category 3 (Hamborg)
Figure 7.30
Yearly distribution of kitesurf days – Total impact – Category 3 (Hamborg)
From the assessment of the combined wind and current impact to surf amenity, it is
demonstrated that the proposed port expansion will cause a reduction of exceptional surf days
(Category 3) of 9% at Hamborg for both windsurfing and kitesurfing. The reduction in Category
2 surf days is respectively 13% for both windsurfing and kitesurfing.
The total amount of surfable days is reduced by 5% for both windsurfing and kitesurfing due to
increased wind sheltering.
7.4
Conclusions
A schematic overview of the resulting impacts is presented in Table 7.7.
Surf Spot
Fisherman’s Corner
Fakir
Fish Factory
Middles
Hamborg
Table 7.7
Wave Induced Impact
No Impact
High
Small
Very Small
Wind Induced Impact
High
Moderate
Small
Combined Impact
No Impact
High
Moderate
Small
Schematic overview of surfing amenity impact due to the proposed Hanstholm Port Expansion
It is concluded that Fisherman’s Corner can expect no impact to surfing amenity caused by the
proposed port expansion.
Being the surf spot on the eastern side of the Port located in closest proximity to the expansion,
Fish Factory will experience a frequent and significant reduction in local wave heights and a
significant reduction in the number of rideable waves, their size and average ride length during
an event. The surf spot is also expected to experience a significant decrease in surfing amenity
due to increased wind turbulence and wind gustiness. The total number of surfable days will be
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reduced noticeable due to increased wind sheltering. Both wave and wind-induced impact will
separately eliminate good and exceptional surf days (Category 2 and 3). The total number of
surfable days is reduced by 18-19%. As a result, calculation shows that the proposed port layout
will cause Fish Factory to lose a significant amount of its surfing amenity and no longer be
considered at good surfing spot.
Middles is located further away from the proposed port expansion, and will experience a much
smaller impact than Fish Factory. Being the preferred surf spot for windsurfing and kitesurfing
in 8 out of 10 surf events, the surfing amenity impact for Middles is considered to be of the
greatest importance for the area. The impact at Middles is expected to be dominantly caused by
increased wind-induced turbulence and gustiness. The wave-induced impacts are expected to
be minor and occur mostly during wave conditions with less energetic wave conditions. The
total decrease in Category 3 is 22-26% and 25%-33% for Category 2 events following the
proposed port expansion. The total number of surfable days is reduced by 11-12%. The
reduction in Category 3 and 2 events means that approximately every third to fourth good or
exceptional surf day will disappear. The reduction of high quality surf events is frequent enough
to be expected to cause frustration among the surfing community, but it is not so frequent that it
is expected to jeopardize the surf spots status as a world class surf spot. As a result, a moderate
and mostly wind-induced reduction in surfing amenity is expected at Middles.
Hamborg is the surf spot located furthest away from the proposed port expansion. It will
experiences very little wave-induced impact and only little wind-induced impact. The total
number of surfable days is reduced by 5% and the reduction in Category 3 and Category 2 is 913%. As a result, the surfing amenity at Hamborg is considered to be largely unaffected by the
proposed Hanstholm Port Expansion.
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8
References
[1]
Port of Hanstholm, 2010, “Oceans of Possibilities”, Profile Flyer 2010,
http://www.hanstholmhavn.dk
[2]
Grontmij A/S, 2012, “Hanstholm Havn, VVM, Surfing, betydning af ændrede vindforhold”,
Technical Note
[3]
AECGroup, 2009, ”Surfing Industry Review and Economic Contributions Assessment”,
Report prepared for Gold Coast City Council
[4]
Influence on surfers wind conditions east of the new Hanstholm harbour/wind turbine
project. Torben J. Larsen and Poul Astrup DTU Wind Energy Report I{0007(EN) July
2012, Rev. 3
[5]
DHI, 2012, “Hanstholm Harbour Extension. Phase 1:Hydraulic Investigations”. Report
prepared for Grontmij A/S.
[6]
DHI, 2011, “Port of Hanstholm. Wave Transformation Modelling”. Report prepared for
Grontmij A/S.
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