Weston Bay Beach and Dune Management Plan Technical Appendix Wave Modelling

June 2013 Draft Report 9Y0510

HASKONING UK LTD. RIVERS, DELTAS & COA STS

Stratus House Emperor Way Exeter, Devon EX1 3QS United Kingdom +44 1392 447999 Telephone 01392 446148 Fax [email protected] E-mail www.royalhaskoningdhv.com Internet

Document title Weston Bay Beach and Dune Management Plan Technical Appendix Wave Modelling Document short title Wave Modelling Status Draft Report Date June 2013 Project name Weston Bay Beach and Dune Management Plan Project number 9Y0510 Client North Somerset Council Reference 9Y0559/R/303395/Exet

Drafted by Martha Gaches and Eddie Crews

Checked by Keming Hu Date/initials check …………………. …………………. Approved by Greg Guthrie Date/initials approval …………………. ………………….

A company of Royal HaskoningDHV

CONTENTS

Page

1 INTRODUCTION 1 1.1 Location 1

2 INPUT DATA FOR WAVE MODELLING 2 2.1 General 2 2.2 Bathymetry 2 2.3 Tide and Still Water Levels 2 2.4 Wave Data 3 2.4.1 Wave Data Sources 3 2.4.2 Offshore Wave Data 3 2.4.3 Nearshore Wave Data 5 2.4.4 Wave Intpus for Spectral Wave (SW) Modelling 8

3 MIKE 21 SPECTRAL WAVE MODEL SET UP 9 3.1 Model Mesh 9 3.2 Model Bathymetry 10 3.3 Location of Model Result 11 3.4 Offshore boundary conditions 12

4 WAVE MODEL RESULTS 14

5 REFERENCES 17

Appendices

Appendix A CCO Nearshore Wave Buoy Data

Appendix B SW Wave Modelling Results (Area Plots)

Weston Bay Beach and Dune Management Plan Technical Appendix – Wave Modelling Draft Report i June 2013

1 INTRODUCTION

This Technical Appendix supports the Weston Bay Beach Management Plan (Weston Bay BMP) commissioned by North Somerset Council (NSC). The document describes the wave modelling conducted for the Weston Bay BMP outlining input data and modelling methodology as well as giving an overview of the results. Analysis and interpretation of the results are provided within the BMP.

1.1 Location

The area covered by the Weston Bay BMP is shown in Figure 1.1, denoted at either end by two black arrows. This area stretches from Brean Cross sluice on the Axe Estuary to the south, to Anchor Head at the north end of Weston Bay.

Figure 1.1 Study Area Location Plan

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2 INPUT DATA FOR WAVE MODELLING

2.1 General

Information for this study has been taken from previous studies undertaken for North Somerset Council including the Weston Sea Front Strategy Study conducted by Royal Haskoning (2004) and the Weston-super-Mare Seawall and Seafront Enhancements Project, also undertaken by Royal Haskoning (2006). The results from these studies, as well as other available data, were reviewed and used in the wave model.

Weston-super-Mare is situated in the Weston Bay process unit of the Severn Estuary Coastal Cell that extends from the rock headland of Birnbeck in the North to Brean Down in the South (as defined in the Severn Estuary Shoreline Management Plan). The limestone headlands protect a bay which is comprised predominantly of fine sediments within the intertidal zone, with a sandy beach around the high water mark. The hinterland at Weston is generally low lying across the extent of the bay. In the north, the back shore is highly developed and protected by a stone seawall which was improved as part of the Seafront Enhancements Project. To the south the backshore is occupied by Weston-super-Mare Golf Club which is protected by a robust ridge of sand dunes.

In summary, extreme waves come predominantly from a westerly direction and are ocean (swell) waves. Smaller, locally generated waves come predominantly from the north. There is a large tidal range of 11.2m (mean spring tides) over a shallow sloping beach of sand and mud.

2.2 Bathymetry

The bathymetry data for this wave model contains CMAP data (Digital Admiralty Chart Soundings), topographic survey data covering an area between Knightstone Island and the Tropicana (Conducted for the Weston-super-Mare Seawall and Seafront Enhancements Project, 2006) and LiDAR data of the study area. The mesh and bathymetry generated using this data can be seen in Figures 3.1 to 3.4.

2.3 Tide and Still Water Levels

Tides at Weston-super-Mare are semi-diurnal i.e. comprising two high tides and two low tides each day. The mean spring tidal range is 11.2m, with a mean neap tidal range of 5.8m.

For the purposes of modelling, tide levels were taken from the Admiralty tide tables for 2013 (Hydrographic Office, 2013), which is the standard now used by the Environment Agency for extreme tide predictions in the South West Region. The tide levels used for modelling purposes are shown in Table 2.1.

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Table 2.1: Spring, neap and extreme tide levels at Weston-super-Mare Levels relative to Levels relative to Tide Level Chart Datum ODNewlyn

(m CD) (m) Chart Datum 0.00 -6.00 Mean Low Water Springs (MLWS) 0.80 -5.20 Mean Low Water Neaps (MLWN) 3.00 -3.00 Mean Water Level (MWL) 6.15 0.15 Mean High Water Neaps (MHWN) 8.80 2.80 Mean High Water (MHW) 10.40 4.40 Mean High Water Springs (MHWS) 12.00 6.00 1Yr Return Period 13.62 7.62 200Yr Return Period 14.43 8.43 1000Yr Return Period 14.76 8.76 NB. Chart datum at Weston-super-Mare is –6.0m Ordinance Datum

2.4 Wave Data

2.4.1 Wave Data Sources

Wave data was available from four sources: 1) Extreme offshore wave heights estimated for the Weston-super-Mare Seawall and Seafront Enhancements: Numerical Modelling of Nearshore Waves and Overtopping (Royal Haskoning, 2006) 2) Estimates of extreme offshore wave heights were available from the Coastal Boundary Conditions Project (Environment Agency 2011a) 3) Annual nearshore Wave Climate created for the Weston Seafront Strategy Study (Posfords Haskoning, 2004) using data from the Bridgwater Bay to Bideford Bay Shoreline Management Plan, Volume 3, Halcrow, 1998. 4) Observational data from the Channel Coastal Observatory (CCO) wave nearshore buoy (downloaded from the CCO website).

It should be noted that the annual nearshore wave climate has been used to validate the model. The other sources have been used for information purposes only.

2.4.2 Offshore Wave Data

Data Source 1: Offshore Extreme Wave Heights, RHDHV for NSC Extreme wave heights from the Weston-super-Mare Seawall and Seafront Enhancements study were derived from scatter table information obtained from the UK Meteorological Office dating from 1st June 1991 to 31st May 2006. These extreme wave heights were estimated for a location at the mouth of the Bristol Channel (51.3ºN 4.5ºW, see Figure 2.1).

A 3-parameter weibull analysis was performed on the scatter table data. This is a widely accepted technique from which to derive estimates of extreme waves. As the site at Weston-super-Mare is west-facing, only waves from the westerly quadrant

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(226 to 315 degrees) were considered for the extrapolation of extreme waves in this study. Table 2.2 summarises the extreme value wave heights.

Table 2.2 Extreme Value Wave Heights Offshore

Return Period Offshore Direction Sector (yrs) 226 o – 255 o 256 o – 285 o 286 o – 315 o Hs (m) Tz (s) Hs (m) Tz (s) Hs (m) Tz (s) 1 5.64 8.34 5.86 8.50 5.28 8.07 5 6.59 9.01 6.92 9.23 6.38 8.86 10 6.98 9.27 7.36 9.52 6.83 9.17 20 7.35 9.52 7.78 9.80 7.27 9.50 50 7.83 9.82 8.33 10.10 7.85 9.83 100 8.19 10.04 8.73 10.40 8.27 10.10 200 8.53 10.25 9.12 10.60 8.69 10.35 300 8.73 10.40 9.35 10.73 8.93 10.50

Hs The wave period was estimated from Tz ≈ 11 . g

Data Source 2: Offshore Extreme Wave Heights, Met Office The estimates of extreme wave heights were derived from simulations of eight years of swell wave activity, undertaken by the Met Office. The closest location at which these data were available was at Wave ID 271, which is approximately 25km south of Swansea, and roughly 60km west northwest of Weston Bay (see Figure 2.1). The extreme estimates of Hs can be seen in Table 2.3.

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Figure 2.1 Location of Offshore Extreme Waves Royal Haskoning (for NSC) and Met Office (Wave ID 271)

Table 2.3 Coastal Boundary Conditions Extreme Wave Height (m) data from Wave ID 271 Return Direction Period Southwest Northwest T1 2.97 2.26 T2 3.08 2.47 T5 3.2 2.69 T10 3.29 2.82 T20 3.36 2.93 T25 3.38 2.96 T50 3.44 3.04 T75 3.47 3.08 T100 3.5 3.1 T150 3.52 3.14 T200 3.54 3.16 T250 3.56 3.17 T300 3.57 3.18 T500 3.6 3.21 T1000 3.63 3.25

It is clear from Table 2.2 and Table 2.3 that there is a significant difference between the offshore wave heights from Data Source 1 and 2. The differences in wave height may arise from the varying locations at which these estimations are made. Figure 2.1 illustrates the locations of both of the data sources. The Met office ID 271 data is further east and it is therefore considered that this would be in relatively sheltered location with shallower water. Both of these factors would reduce the estimated wave heights.

2.4.3 Nearshore Wave Data

Data Source 3: Nearshore Annual Wave Climate An annual wave climate was generated for the Weston Seafront Strategy Study (Posfords Haskoning, 2004). It was derived using data from the Bridgwater Bay to Bideford Bay Shoreline Management Plan, Volume 3, Halcrow, 1998.

The main directions of wave attack are between 240° and 300° with the largest waves coming directly towards the bay from 270°. Smaller , locally generated waves come predominantly from the north. A wave rose illustrating this data set is shown below in Figure 2.2.

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Figure 2.2 – Wave Climate Rose Based on the SMP 1998

The derived annual wave climate can be seen in Table 2.4 below.

Table 2.4: Annual wave climate for Weston Bay, wave duration in days

Wave Direction (degrees) height Hs(m) 195 o-225 o 225 o-255 o 255 o-285 o 285 o-315 o 315 o-345 o 345 o-015 o 6.0-6.5 0 0 0 0 0 0 5.5-6.0 0 0 0 0 0 0 5.0-5.5 0 0 0 0 0 0 , , m)

s 4.5-5.0 0 0 0 0 0 0 4.0-4.5 0 0 0 0 0 0 3.5-4.0 0 0 0 0 0 0

Height (H 3.0-3.5 0 0 0 0 0 0 2.5-3.0 0 0 1 0 0 0 2.0-2.5 0 1 4 0 0 0 1.5-2.0 0 5 10 1 0 0 1.0-1.5 3 10 20 4 1 0 0.5-1.0 8 9 35 5 3 0 0.0-0.5 8 10 34 10 10 172

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Data Source 4: CCO Nearshore Wave Buoy Data Two full years of observational wave data were obtained from the CCO database. These observational data were recorded around 2km west of Knightstone Harbour (51.3543N 3.0175W), as illustrated in Figure 2.3. The data record runs from September 2009 to September 2012 (Data is not available for 2011 as the wave buoy was out of action at this time). The observed wave data can be found in Appendix A.

Figure 2.3 - Location of Nearshore Wave Buoy

The wave rose illustrated in Figure 2.4 shows the inshore wave climate for Weston Bay based on the significant wave height taken from the observational data, courtesy of the Channel Coastal Observatory (CCO). This describes the wave climate as being dominated by waves from the west and southwest. Significant wave heights vary with a maximum recorded wave height from a wave buoy just off Weston Bay of 2.77m between September 2009 and September 2012.

Figure 2.4 – Wave Climate Rose Based on the Wave Buoy Data

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2.4.4 Wave Inputs for Spectral Wave (SW) Modelling

In order to cover the desired spectrum of significant wave heights in the SW modelling three different wave heights were selected to represent three different bands of wave height. These wave bands were; a 1.5m wave which covers 0.5m to 1.9m waves, a 3 m wave which covers 2 to 3.9 m and a 5m wave which covers waves above 4m.

These wave heights were run from the three most dominant wave directions 240, 270 and 300 degrees. This run information can be found in Table 3.1 in Section 3.4

2.5 Wind Data

Wind data has been obtained from Appendix C of the Severn Estuary Shoreline Management Plan. The wind rose is located on Flat Holm which is identified on Figure 2.3. The main wind direction is from the south-westerly and north-easterly with the maximum wind speed related to the south westerly winds (Figure 2.5). However, storms tend to be from one direction, typically approaching from the southwest. Wind waves can be generated anywhere within the estuary, but their size is dependent on the fetch distance across which the wind blows to enable wave generation (SMP 2010).

Figure 2.5 – Flat Holm Wind Rose (SMP 2010)

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3 MIKE 21 SPECTRAL WAVE MODEL SET UP

The numerical modelling tool MIKE 21 SW was used to represent the transformation of wave activity from the offshore to the nearshore. MIKE 21 SW is an industry standard package that simulates the growth, decay and transformation of wind-generated waves and swells in offshore and coastal areas. It accounts for the following processes (amongst others):

• Wave growth by action of wind • Non-linear wave-wave interaction • Dissipation due to white-capping • Dissipation due to depth-induced wave breaking • Refraction and shoaling due to depth variations • Diffraction • Reflection

3.1 Model Mesh

Model construction required data describing the topography of the seabed, along with water levels and offshore wave conditions. The bathymetric data used in this project is described in Section 2.2.

The topographic data were used to generate a large irregular triangular mesh, for use as a template for the calculations of wave activity and transformation. This mesh extended from the mouth of the Bristol Channel between Rhossili on the Gower peninsula and Mortehoe on the north Devon coast, as illustrated in Figure 3.1.

Figure 3.1 Overview of the SW model mesh

The greater the detail of this triangular network the more precise the calculations, but the greater the processing time needed for each simulation. Precision is most needed close to the land, where bathymetry changes most rapidly, and where features of the shoreline enhance shoaling and refraction effects. For this reason the resolution of the

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grid was increased with proximity to the land in a series of three steps, as can be seen in Figure 3.2.

Figure 3.2 - Weston-Super-Mare SW model mesh detail

3.2 Model Bathymetry

Figure 3.3 - SW Model Bathymetry

The model accounts for the seabed level at each node within the grid. These levels are illustrated in Figure 3.3 for the whole model domain and are shown in more detail for the study area in Figure 3.4.

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Figure 3.4 SW Detailed Model Bathymetry showing Weston Bay

3.3 Location of Model Result

Ten output locations were selected across Weston Bay to give a set of near shore wave conditions and outputs were also generated for the full model area. These output locations can be seen in Figure 3.5

10 13

14 11 15

16

12 17

18 19

Figure 3.5 SW Model Output Locations

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3.4 Offshore boundary conditions

3.4.1 Swell Wave Modelling Parameters

The parameters of every simulation included water level, wave height and wave period. As discussed earlier in Section 2.4.4 three different significant wave heights were used to cover 3 bands; a 1.5m wave which covers 0.5m to 1.9m waves, a 3 m wave which covers 2 to 3.9 m and a 5m wave which covers waves above 4m.

The MHWS tide level was used as this is a level at which the upper beach is most exposed to wave attack. This is also a water level at which a large proportion of the beach is submerged, and therefore demonstrated how waves transform over the intertidal zone.

Table 3.1 Spectral Wave Model Run Parameters (Swell)

Still Water Level Mean Wave Run Hs Tz Tp (mCD) Direction 1 12 1.5 4.30 6.2 240 2 12 3 6.08 8.8 240 3 12 5 7.85 11.3 240 4 12 1.5 4.30 6.2 270 5 12 3 6.08 8.8 270 6 12 5 7.85 11.3 270 7 12 1.5 4.30 6.2 300 8 12 3 6.08 8.8 300 9 12 5 7.85 11.3 300

Wave periods were estimated using the following formula to calculate zero crossing period (Tz)

Hs Tz ≈ 11 g

Where: Hs = significant wave height (m) g = gravity (9.81 ms -2) Tz = zero crossing period (secs)

and peak period (Tp) was created using

Tz x 1.44 = Tp

Tz = zero crossing period (secs) Tp = peak period (secs)

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3.4.2 Wind Wave Modelling Parameters

Further modelling runs have been undertaken to reflect the significant wind conditions occur in the Bristol Channel. The parameters of the 4 runs are included below in Table 3.2. These parameters have been derived from the wind rose (Figure 2.5). Runs have only been carried out for the three most significant westerly winds and one north easterly wind. The midpoint each segment is forms the wind direction whereas the mean average of the most extreme recorded wind speed band forms the wind speed (i.e. 33 knots taken as the wind speed for the 30 – 36kn band).

Table 3.2 Spectral Wave Model Run Parameters (Wind) Run Wind Direction (Degrees) Wind Speed (Knots) Wind Speed (m/s) 1 261 33 16.97 2 243 33 16.97 3 279 27 13.89 4 45 21 10.80

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4 WAVE MODEL RESULTS

4.1 Swell Waves

Figure 4.1 and 4.2 respectively illustrate a wide and zoomed view of the transformation of the 5m swell wave travelling at 270º (Run 6), which is approximately normal to Weston Bay. These waves solely represent swell wave with not inclusion of wind. Figure 4.1 illustrates that wave height is significantly reduced as the waves travel east up the Bristol Channel. Waves with heights in excess of 4.8m at the model boundary are reduced to around 1m on arrival to Weston Bay (Figure 4.2). This suggests that the wave climate within the bay is dominated by locally generated wind waves.

Figure 4.2 – Transformation of a Swell Wave within the Bristol Channel

Figure 4.2 – Transformation of a Swell Wave within Weston Bay

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Data was extracted from each simulation at the ten locations across Weston Bay (see Figure 3.5). The wave heights, periods and average directions at the ten output location results can be found in Appendix A with associated plots for these runs.

4.2 Wind Waves

Figures 4.3 to 4.5 illustrate three views Run 1 (Table 3.2) which represents a 16.97ms -1 wind with a direction of 261º which represents the most extreme wind condition recorded on the wind rose (Figure 2.5). Scaled up versions of the full output plots are included in Appendix B, (Figures 4.3 to 4.4 are for reference purposes only).

Figure 4.3 – Wind Wave through the Bristol Channel

Figure 4.3 illustrates the nature of the wind wave model, highlighting the continual increase in wave height from west to east resulting from the constant wind condition being applied within the boundaries of the model. Figure 4.4 illustrates the relative protection that is provided by the Island of Steep Holm with significantly larger waves observed to the south of Brean Down.

Figure 4.4 – Wind Wave past Steep Holm and Flat Holm

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Figure 4.5 – Wind Wave past Steep Holm and Flat Holm

Figure 4.5 illustrates, not only the heights within the bay but also provides velocity vectors of the waves. With the exception of the far north and south, waves generally approach the bay normally. In the north there appears to be minimal diffraction and the curvature of the bay causes waves to approach at a slight angle. In the south of the bay wave heights appear to be smaller as a result of the protection provided by Brean Down. The vectors also suggest that diffraction is occurring in the southern corner.

Data was extracted from each simulation at the ten locations across Weston Bay (see Figure 3.5). The wave heights, periods and average directions at the ten output location results can be found in Appendix B with associated plots for these runs.

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References

Royal Haskoning (2004). Weston Sea Defences, Hydraulic Analysis, North Somerset Council

Royal Haskoning (2006). Weston super Mare Seawall and Seafront Enhancements: Numerical Modelling of Nearshore Waves and Overtopping , North Somerset Council

Hydrographic Office, (2013). Admiralty tide tables

Environment Agency (2011a.) The Coastal Boundary Conditions Project, Estimates of extreme offshore wave heights

Posfords Haskoning (2004) Weston Seafront Strategy Study, (data from the Bridgwater Bay to Bideford Bay Shoreline Management Plan, Volume 3, Halcrow, 1998) North Somerset Council

Atkins (2010) Severn Estuary Shoreline Management Plan Review (SMP2) – Appendix C: (A) Baseline Understanding of Coastal Behaviour and Dunamics, (B) Coastal Defences and (C) Baseline Scenario Report, Severn Estuary Coastal Group, Atkins December 2010.

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APPENDIX A Swell Output Results Table

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Figure A.1 - SW Model Output Locations

Table A.1 – Resulting Significant Wave Heights for each of the Ten Output Locations

Significant Wave Height (m) during Run Number Output Location 1 2 3 4 5 6 7 8 9

10 0.47 0.50 0.54 0.63 0.68 0.76 0.43 0.53 0.67 11 0.45 0.53 0.61 0.61 0.74 0.87 0.42 0.57 0.77 12 0.43 0.52 0.59 0.60 0.72 0.84 0.42 0.56 0.75 13 0.35 0.40 0.44 0.43 0.50 0.56 0.33 0.42 0.52 14 0.47 0.56 0.64 0.59 0.73 0.84 0.44 0.59 0.76 15 0.45 0.58 0.68 0.59 0.78 0.92 0.42 0.62 0.83 16 0.44 0.57 0.66 0.57 0.73 0.88 0.43 0.60 0.79 17 0.42 0.57 0.66 0.58 0.76 0.90 0.43 0.61 0.81 18 0.34 0.49 0.58 0.48 0.67 0.81 0.36 0.53 0.72 19 0.21 0.31 0.37 0.30 0.43 0.52 0.22 0.33 0.46

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Table A.2 – Resulting Peak Wave Periods for each of the Ten Output Locations

Peak Wave Period (s) Run Number Output Location 1 2 3 4 5 6 7 8 9

10 6 9 11 6 9 10 6 9 10 11 6 9 11 6 9 10 6 9 10 12 6 9 11 6 9 10 6 9 10 13 6 8 10 6 8 10 6 8 10 14 6 8 10 6 8 10 6 8 10 15 6 8 10 6 8 10 6 8 10 16 6 8 10 6 8 10 6 8 10 17 6 8 10 6 8 10 6 8 10 18 6 8 10 6 8 10 6 8 10 19 6 8 10 6 8 10 6 8 10

Table A.3 – Resulting Wave Periods T01 for each of the Ten Output Locations

Wave Period T01 (s) Run Number Output Location 1 2 3 4 5 6 7 8 9

10 5 7 9 5 7 9 5 7 9 11 5 7 9 5 7 9 5 7 9 12 5 7 9 5 7 9 5 7 9 13 5 7 8 5 7 8 5 7 8 14 5 7 8 5 7 8 5 7 8 15 5 7 8 5 7 8 5 7 8 16 5 7 8 5 7 8 5 7 8 17 5 7 8 5 7 8 5 7 8 18 5 7 9 5 7 8 5 7 8 19 5 7 9 5 7 8 5 7 8

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Table A.4 – Resulting Mean Wave Direction for each of the Ten Output Locations

Mean Wave Direction (deg.) Run Number Output Location 1 2 3 4 5 6 7 8 9

10 279 281 281 280 281 280 280 281 280 11 274 273 272 275 273 272 276 273 272 12 274 274 274 274 274 274 275 274 274 13 246 245 244 246 245 245 246 245 245 14 275 275 275 275 275 274 276 275 274 15 275 277 276 276 276 276 277 276 276 16 276 277 277 276 277 277 277 277 277 17 280 282 282 280 282 282 281 282 282 18 285 287 287 285 287 287 285 287 287 19 301 299 299 299 298 298 298 298 298

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APPENDIX B Wind Wave Output Results Table

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Table B.1 – Resulting Significant Wave Heights

Significant Wave Height - Output Location Run 10 11 12 13 14 15 16 17 18 19 1 2.63 2.64 2.33 0.99 1.52 1.64 1.34 1.64 1.71 1.38 2 2.44 2.36 1.91 0.98 1.48 1.59 1.30 1.54 1.55 1.09 3 1.95 1.94 1.80 0.87 1.35 1.46 1.21 1.44 1.50 1.14 4 0.60 0.68 0.75 0.30 0.33 0.33 0.35 0.36 0.35 0.38

Table B.2 – Resulting Peak Period

Peak Period - Output Location Run 10 11 12 13 14 15 16 17 18 19 1 6.79 6.85 6.89 6.85 6.90 6.94 7.04 6.95 6.95 6.95 2 6.43 6.48 6.68 6.46 6.60 6.70 6.81 6.80 6.84 6.86 3 6.12 6.15 6.17 6.18 6.21 6.22 6.25 6.23 6.22 6.21 4 4.80 3.65 3.66 6.23 6.26 6.28 6.28 6.28 6.29 5.40

Table B.3 – Resulting T01 Wave Period

Wave Period - Output Location Run 10 11 12 13 14 15 16 17 18 19 1 5.25 5.33 5.14 5.89 6.08 6.11 6.13 5.95 5.77 5.28 2 5.02 5.12 5.16 5.53 5.78 5.82 5.87 5.72 5.57 5.26 3 4.61 4.64 4.45 5.16 5.22 5.20 5.25 4.99 4.76 4.28 4 3.13 3.11 3.09 4.02 4.35 4.14 4.13 3.52 3.02 2.66

Table B.4 – Resulting Significant Wave Heights

Mean Wave Direction Run 10 11 12 13 14 15 16 17 18 19 1 274 271 275 248 273 275 277 282 286 296 2 268 267 274 246 271 274 276 281 286 295 3 279 275 278 247 274 276 277 282 287 298 4 332 340 348 233 263 269 275 292 316 340

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APPENDIX C CCO Nearshore Wave Buoy Data

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Table C.1 - Wave Data – Raw Frequency

0 - 0.1 - 0.25m - 0.5m - 0.75m - 1.0m - 1.25m+ 0.1m 0.25m 0.5m 0.75m 1.0m 1.25m 240 908 2192 2596 2574 733 254 112 270 1383 3825 3918 4638 1276 654 475 300 540 455 288 142 32 7 3 330 453 783 272 49 15 4 1 360 229 1136 1071 326 70 7 0

Table C.2 - Wave Data – Percentage Distribution

0 - 0 - 0.25m - 0.5m - 0.75m - 1.0m - 1.25+ 0.1m 0.25m 0.5m 0.75m 1.0m 1.25m 240 2.89% 6.98% 8.26% 8.19% 2.33% 0.81% 0.36% 270 4.40% 12.17% 12.47% 14.76% 4.06% 2.08% 1.51% 300 1.72% 1.45% 0.92% 0.45% 0.10% 0.02% 0.01% 330 1.44% 2.49% 0.87% 0.16% 0.05% 0.01% 0.00% 360 0.73% 3.62% 3.41% 1.04% 0.22% 0.02% 0.00%

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Appendix D SW Wave Modelling Results (Area Plots)

Weston Bay Beach and Dune Management Plan Technical Appendix – Wave Modelling Draft Report June 2013Draft Report Run 1 - Wide View

Run 1 – Intermediate View

Run 1 – Zoomed View

Run 2 – Wide View

Run 2 – Intermediate View

Run 2 – Zoomed View

Run 3 – Wide View

Run 3 – Intermediate View

Run 3 – Zoomed View

Run 4 – Wide View

Run 4 – Intermediate View A

Run 4 – Intermediate View B

Run 4 – Zoomed View