DEPARTMENT OF PRIMARY INDUSTRIES

Fisheries Research Report Series Eastern Bay Aquaculture Fisheries Reserves - , wind and wave data

No. 17 May 2004 Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data

May 2004

Fisheries Victoria Research Report Series No.17.

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data © The State of Victoria, Department of Primary Preferred way to cite this publication: Industries, 2004 Fisheries Victoria, 2003. Eastern Port Phillip Bay This publication is copyright. No part may be Aquaculture Fisheries Reserves – current, wind produced by any process except in accordance and wave data. Fisheries Victoria, Research with the provisions of the Copyright Act 1968. Report Series No.17. Reproduction and the making available of this Authorised by the Victorian Government, material for personal, in-house, or non- 232 Victoria Parade, East commercial purposes is authorised on the Published by the Department of Primary condition that: Industries. • The copyright is acknowledged as the owner; Fisheries Victoria • No official connection is claimed; PO Box 500 East Melbourne Victoria 3002. • The material is made available without charge or cost; and Copies are available from the website: www.dpi.vic.gov.au/fishing • The material is not subject to inaccurate, misleading or derogatory comment. Follow the links Managing Fisheries, Management Plans and Strategies Requests to reproduce or communicate this material in any way not permitted by this licence Disclaimer: This publication may be of assistance (or by the fair dealing provisions of the Copyright to you, but the State of Victoria and its employees Act 1968) should be directed to the Copyright do not guarantee that the publication is without Officer, 6/232 Victoria Parade, East Melbourne, flaw or is wholly appropriate for your particular 3002. purposes and therefore disclaims all liability for error, loss or other consequence which may arise ISSN: 1448-7373 from you relying on any information in this ISBN: 1 74146 247 publication.

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data ii Contents

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data...... 1 Wind speed, direction and frequency ...... 1 Current speed, direction and frequency ...... 2 Significant wave height, direction and frequency ...... 2 Figure 1: The Eastern Port Phillip Bay Aquaculture Fisheries Reserves...... 4 Figure 2: Frequency distribution of wind speed and direction at the South Channel Fort Wind Station (1/1/2000 to 31/12/2000)...... 5 Figure 3: Frequency distribution of wind speed and direction at the Fawkner Beacon Wind Station (1/1/2000 to 31/12/2000) ...... 6 Figure 4: Modelled frequency distribution of peak surface current speed and direction for the Dromana Aquaculture Fisheries Reserve ...... 7 Figure 5: Modelled frequency distribution of peak mid-water current speed and direction for the Dromana Aquaculture Fisheries Reserve ...... 8 Figure 6: Modelled frequency distribution of peak surface current speed and direction for the Mount Martha Aquaculture Fisheries Reserve ...... 9 Figure 7: Modelled frequency distribution of peak mid-water current speed and direction for the Mount Martha Aquaculture Fisheries Reserve ...... 10 Figure 8: Modelled frequency distribution of peak surface current speed and direction for the Beaumaris Aquaculture Fisheries Reserve ...... 11 Figure 9: Modelled frequency distribution of peak mid-water current speed and direction for the Beaumaris Aquaculture Fisheries Reserve ...... 12 Figure 10: Modelled frequency distribution of wave direction and significant wave height for the Dromana Aquaculture Fisheries Reserve ...... 13 Figure 11: Modelled frequency distribution of wave direction and significant wave height for the Mount Martha Aquaculture Fisheries Reserve ...... 14 Figure 12: Modelled frequency distribution of wave direction and significant wave height for the Beaumaris Aquaculture Fisheries Reserve ...... 15 Table 1 Wave characteristics for steady 40 knot wind scenarios for the Dromana Aquaculture Fisheries Reserve...... 16 Table 2 Wave characteristics for steady 40 knot wind scenarios for the Mount Martha Aquaculture Fisheries Reserve...... 16 Table 3 Wave characteristics for steady 40 knot wind scenarios for the Beaumaris Aquaculture Fisheries Reserve...... 17

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data iii Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data

At the request of Fisheries Victoria, the Primary 2003 for South Channel Fort wind sampling Industries Research Victoria (PIRVic), Queenscliff station using wind rose analysis. The only Centre undertook an assessment of the physical significant difference was that the strongest SW characteristics (winds, currents and waves) of the and NW winds occurred about 0.5% more Eastern Port Phillip Bay Aquaculture Fisheries frequently on average between 1975 and 2003 Reserves (the Reserves). which are: than they did in 2000. As a result the 2000 data • the Dromana Aquaculture Fisheries Reserve; was considered appropriately representative for the area. • the Mount Martha Aquaculture Fisheries Reserve; and The most dominant wind directions at the South • the Beaumaris Aquaculture Fisheries Reserve. Channel Fort Wind Station in the year 2000 are from the south which occurs 20% of the time, The location and coordinates of the Reserves are followed by north (18%) and then west (17%) described in the Draft Eastern Port Phillip Bay (Figure 2). For winds greater than 30 km/h, the Aquaculture Fisheries Reserves Management Plan and prevailing direction was from the north (8.0%) are shown in Figure 1. followed by west (7.6%), then south (6.5%) (Figure Historical wind data from the South Channel Fort 2). wind station was collated and assessed for the The most common wind speed range at the South Dromana and Mount Martha aquaculture Channel Fort Wind Station in the year 2000 was fisheries reserves. Historical wind data from the 21 - 30km/h (35%) followed by the 11 - 20km/h Fawkner Beacon wind station was collated and and 31 - 40 km/h (20%), greater than 40 km/h assessed for the Beaumaris Aquaculture Fisheries (16%) and 10 km/h or less (7%) (Figure 2). Reserve. Current speed and direction at the surface and mid-water, and significant wave The permanent Bureau of Meteorology weather heights and directional frequencies for each station nearest to the Beaumaris Aquaculture Reserve were predicted using the historical wind Fisheries Reserve is located at the Fawkner data in a hydrodynamic and wave modelling Beacon. It is located approximately 14 km north- program with the Port Phillip Bay (PPB) 400 west of the Beaumaris Aquaculture Fisheries metre bathymetric grid. The wind and modelled Reserve. data are summarised below. Wind data collected between 1/1/2000 and 31/12/2000 by the Bureau of Meteorology at the Wind speed, direction and Fawkner Beacon Wind Station is summarised in frequency Figure 3. Comparison of wind data from the year The permanent Bureau of Meteorology weather 2000 with that from the period 1992 to 2002 station nearest to the Dromana and Mount Martha indicated that year 2000 winds are similar to the aquaculture fisheries reserves is located at the long-term average at the Fawkner Beacon. South Channel Fort. It is located approximately: The most predominant winds at the Fawkner • 16 km west of the Dromana Aquaculture Beacon Wind Station in the year 2000 are from the Fisheries Reserve; and north which occurs 27% of the time, followed by • 20 km south-west of the Mount Martha south (19%) and then west (13%) (Figure 3). For Aquaculture Fisheries Reserve. wind speeds greater than 30 km/h, the predominant wind directions were from the north Wind data collected between 1/1/2000 and (10.2%), followed by those from the west (4.3%), 31/12/2000 by the Bureau of Meteorology at the south (3.5%) and south-west (3.5%) (Figure 3). South Channel Fort Wind Station is summarised in Figure 2. This data was compared to the long- The most common wind speed range at the term average wind data for the period 1975 to Fawkner Beacon Wind Station in the year 2000

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 1 was 21 - 30km/h (33%) followed by the 11 - 7). Mid-water current direction at the MMAFR 20km/h (27%), 31 - 40 km/h (17%), 10 km/h or less was fairly stable on the flood between north (14%) and greater than 40 km/h (10%) (Figure 3). and north-north-east. Current direction on the ebb tide varied between south-west and south-south- Current speed, direction and west (Figure 7). frequency Beaumaris Aquaculture Fisheries Reserve Hydrodynamic and wave modelling using the The surface peak ebb and flood current speeds at 3DD Suite was undertaken at three model sample the Beaumaris Aquaculture Fisheries Reserve sites, one located centrally in each of the Reserves. (BAFR) were generally between 0.02-0.12 m/s, occasionally peaking at over 0.14 m/s (Figure 8). Current speed, direction and frequency were Surface current direction at the BAFR on the flood modelled using wind data from 7 October 2000 to tide ranged between north and east. Current 29 October 2000. This period was used as it direction on the ebb tide varied between west and exhibited a good spring to neap tide range and a south-south-west (Figure 8). variety of wind speeds and directions. The mid-water peak ebb and flood current speeds The model allows for currents to be extracted at the BAFR were between 0.02-0.10 m/s (Figure from an exact position, that is, to a fraction of a 9). Mid-water current direction at the BAFR was grid cell. This is achieved by interpolating from fairly stable on the flood tide between north-east the surrounding cells. and east-north-east. Current direction on the ebb Current speed, direction and frequency were tide varied between west and west-south-west modelled at each of the Reserves at the surface (Figure 9). and at mid-water. Significant wave height, direction Dromana Aquaculture Fisheries Reserve The surface peak ebb and flood current speeds at and frequency the Dromana Aquaculture Fisheries Reserve The 3DD Suite model WGEN was used for wave (DAFR) were generally between 0.04-0.18 m/s, modelling based on the collected wind data occasionally peaking up to 0.30 m/s (Figure 4). utilising the ‘JONSWAP’ generation formula. This Surface current direction at the DAFR was fairly model caters for local wave generation in enclosed stable on the flood tide between north and north- and semi-enclosed water bodies such as the Port east. Current direction on the ebb tide varied Phillip Bay (PPB). between south-south-west and south-south-east The narrowness of the PPB heads prevents most (Figure 4). wave energy entering the bay. waves that The mid-water peak ebb and flood current speeds do enter PPB will break on the shallow banks of at the DAFR were generally between 0.04-0.14 the Great Sands virtually extinguishing the wave m/s, occasionally peaking at over 0.20 m/s (Figure energy. As a result swell waves reaching inner 5). Mid-water current direction at the DAFR was PPB are therefore not considered to be of any real fairly stable on the flood tide between north and consequence for the present wave modelling north-east. Current direction on the ebb tide exercise. varied between south-south-west and south To characterise the wave action, a year of (Figure 5). modelling using real winds covering the year 2000 Mount Martha Aquaculture Fisheries Reserve was undertaken for each of the Reserves. A 400 m The surface peak ebb and flood current speeds at hydrodynamic modelling bathymetric grid of PPB the Mount Martha Aquaculture Fisheries Reserve was used for the wave modelling. The wave (MMAFR) were generally between 0.04-0.16 m/s, model permits positions to be extracted to the occasionally peaking at over 0.24 m/s (Figure 6). nearest 400m grid cell. However, the waves are Surface current direction at the MMAFR was less likely to change rapidly from cell to cell, fairly stable on the flood tide between north and especially in open water. north-east. Current direction on the ebb tide Wave modelling results for the Reserves are varied between south-south-west and south shown in figures 10 to 12. All wave heights (Figure 6). mentioned are significant wave heights, which is The mid-water peak ebb and flood current speeds the average of the greatest 1/3 of the wave heights. at the MMAFR were generally between 0.04-0.14 A maximum wave height can be up to double a m/s, occasionally peaking at over 0.16 m/s (Figure significant wave height.

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 2 Dromana Aquaculture Fisheries Reserve Beaumaris Aquaculture Fisheries Reserve Calm conditions with waves less than 0.5 metres Calm conditions with waves less than 0.5 metres occurred about 62% of the year at the DAFR occurred about 72% of the year in the BAFR (Figure 10). The DAFR experienced waves (Figure 12). The BAFR experienced waves between 0.5 and 1.0 metres 28% of the year and between 0.5 and 1.0 metres 24% of the year and those between 1.0 and 1.5 metres 9% of the year. those between 1.0 and 1.5 metres 4% of the year. Waves between 1.5 and 2.0 metres were The largest waves came predominantly from the experienced less than 1% of the year. west to the south, primarily a result of these The largest waves came predominantly from the directions having the greatest fetch length, west west to the north, primarily a result of these 27.1 km, south-west 41.1 km and south 28.6 km. directions having the greatest fetch distance, west The BAFR is protected from the predominant 24.9 km, north-west 39.2 km and north 35.1 km. In strong northerly winds in eastern PPB by its close addition, some of the strongest winds affecting proximity to the coast (1.4 km). In addition, strong south-eastern Port Phillip Bay are from the west winds affecting eastern PPB also occur from the and the north. south to the west. The significant wave height, peak spectral period The significant wave height, peak spectral period and fetch for a steady 40 knot wind from a variety and fetch for a steady 40 knot wind from a variety of wind directions are shown in Table 1. Under a of wind directions are shown in Table 3. Under a modelled steady 40 knot wind the highest modelled steady 40 knot wind the highest significant wave height at the DAFR is likely to be significant wave height at the BAFR is likely to be 2.1 metres from the north-west. 2.2 metres from the south-west. Mount Martha Aquaculture Fisheries Reserve Calm conditions with waves less than 0.5 metres occurred about 56% of the year in the MMAFR (Figure 11). The MMAFR experienced waves between 0.5 and 1.0 metres 33% of the year and those between 1 and 1.5 metres 11% of the year. Waves between 1.5 and 2.0 metres were experienced less than 1% of the year. The largest waves came predominantly from the west to the north, primarily a result of these directions having the greatest fetch distance, west 32.6 km, north-west 38.4 km and north 30.6 km. In addition, some of the strongest winds affecting south-eastern Port Phillip Bay are from the west and the north. The significant wave height, peak spectral period and fetch for a steady 40 knot wind from a variety of wind directions are shown in Table 2. Under a modelled steady 40 knot wind the highest significant wave height at the MMAFR is likely to be 2.1 metres from the north-west.

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 3 Figure 1: The Eastern Port Phillip Bay Aquaculture Fisheries Reserves.

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 4 N 9%

8% 1–10 km/h 7% 11–20 km/h NW NE 21–30 km/h 6% 31–40 km/h 5% >40 km/h 4% 3% 2% 1% W 0% E

SW SE

S

Figure 2: Frequency distribution of wind speed and direction at the South Channel Fort Wind Station (1/1/2000 to 31/12/2000)

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 5 N 8%

7% 1–10 km/h 11–20 km/h 6% NW NE 21–30 km/h 5% 31–40 km/h

4% >40 km/h

3%

2%

1%

W 0% E

SW SE

S

Figure 3: Frequency distribution of wind speed and direction at the Fawkner Beacon Wind Station (1/1/2000 to 31/12/2000)

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 6 N 12% NNW NNE

10% 0-5 cm/s NW NE 5-10 cm/s 8% 10-15 cm/s Flood tide 15-20 cm/s 6% 20+ cm/s WNW ENE 4%

2%

W 0% E

WSW ESE

Ebb tide

SW SE

SSW SSE

S

Figure 4: Modelled frequency distribution of peak surface current speed and direction for the Dromana Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 7 N 16% NNW NNE 14%

NW 12% NE Flood tide 10% 0-5 cm/s 8% 5-10 cm/s 10-15 cm/s WNW 6% ENE 15-20 cm/s 4% 20+ cm/s 2%

W 0% E

Ebb tide

WSW ESE

SW SE

SSW SSE

S

Figure 5: Modelled frequency distribution of peak mid-water current speed and direction for the Dromana Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 8 N 12% NNW NNE

10% 0-5 cm/s NW NE 5-10 cm/s 8% 10-15 cm/s 15-20 cm/s 6% Flood tide 20+ cm/s WNW ENE 4%

2%

W 0% E

WSW Ebb tide ESE

SW SE

SSW SSE

S

Figure 6: Modelled frequency distribution of peak surface current speed and direction for the Mount Martha Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 9 N 16% NNW NNE 14%

NW 12% NE 10% 0-5 cm/s 8% Flood tide 5-10 cm/s 10-15 cm/s WNW 6% ENE 15-20 cm/s 4% 20+ cm/s 2%

W 0% E

WSW ESE Ebb tide

SW SE

SSW SSE

S

Figure 7: Modelled frequency distribution of peak mid-water current speed and direction for the Mount Martha Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 10 N 12% NNW NNE

10% 0-5 cm/s NW NE 5-10 cm/s 8% 10-15 cm/s 15-20 cm/s 6% 20+ cm/s WNW ENE 4% Flood tide

2%

W 0% E

Ebb tide

WSW ESE

SW SE

SSW SSE

S

Figure 8: Modelled frequency distribution of peak surface current speed and direction for the Beaumaris Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 11 N 30% NNW NNE

25% NW NE 20% 0-5 cm/s 15% 5-10 cm/s 10-15 cm/s WNW ENE 10% 15-20 cm/s Flood tide 20+ cm/s 5%

W 0% E Ebb tide

WSW ESE

SW SE

SSW SSE

S

Figure 9: Modelled frequency distribution of peak mid-water current speed and direction for the Beaumaris Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 12 N 14% NNW NNE

12% <0.5 m

NW 10% NE 0.5-1.0 m 1.0-1.5 m 8% >1.5 m 6% WNW ENE 4%

2%

W 0% E

WSW ESE

SW SE

SSW SSE

S

Figure 10: Modelled frequency distribution of wave direction and significant wave height for the Dromana Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 13 N 12% NNW NNE

10% <0.5 m NW NE 0.5-1.0 m 8% 1.0-1.5 m 6% >1.5 m WNW ENE 4%

2%

W 0% E

WSW ESE

SW SE

SSW SSE

S

Figure 11: Modelled frequency distribution of wave direction and significant wave height for the Mount Martha Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 14 N 25% NNW NNE

<0.5 m 20% NW NE 0.5-1.0 m

15% 1.0-1.5 m >1.5 m WNW 10% ENE

5%

W 0% E

WSW ESE

SW SE

SSW SSE

S

Figure 12: Modelled frequency distribution of wave direction and significant wave height for the Beaumaris Aquaculture Fisheries Reserve

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 15 Table 1 Wave characteristics for steady 40 knot wind scenarios for the Dromana Aquaculture Fisheries Reserve. Wind speed Wind direction Fetch Water depth at sample site Significant wave height Peak spectral period of waves (m/s) (degrees true) (km) (m) (m) (s) 20.6 360 35.1 11.0 2.0 5.5 20.6 90 1.9 11.0 0.5 2.1 20.6 180 3.4 11.0 0.6 2.5 20.6 225 11.7 11.0 1.2 3.8 20.6 270 24.9 11.0 1.7 4.9 20.6 315 39.2 11.0 2.1 5.7

Table 2 Wave characteristics for steady 40 knot wind scenarios for the Mount Martha Aquaculture Fisheries Reserve. Wind speed Wind direction Fetch Water depth at sample site Significant wave height Peak spectral period of waves (m/s) (degrees true) (km) (m) (m) (s) 20.6 360 30.6 17.0 1.9 5.2 20.6 90 2.0 17.0 0.5 2.1 20.6 180 6.9 17.0 0.9 3.2 20.6 225 20.3 17.0 1.5 4.6 20.6 270 32.6 17.0 1.9 5.3 20.6 315 38.4 17.0 2.1 5.6

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 16 Table 3 Wave characteristics for steady 40 knot wind scenarios for the Beaumaris Aquaculture Fisheries Reserve. Wind speed Wind direction Fetch Water depth at sample site Significant wave height Peak spectral period of waves (m/s) (degrees true) (km) (m) (m) (s) 20.6 360 1.4 6.0 0.4 1.9 20.6 135 10.1 6.0 1.1 3.6 20.6 180 28.6 6.0 1.8 5.1 20.6 225 41.1 6.0 2.2 5.8 20.6 270 27.1 6.0 1.8 5.0 20.6 315 6.5 6.0 0.9 3.1

Eastern Port Phillip Bay Aquaculture Fisheries Reserves – current, wind and wave data 17