Jurien Bay Boat Harbour

The Department of Transport is progressing research to improve the harbour environment in the Jurien Bay Boat Harbour.

Computer modelling to simulate floating seagrass and seaweed (wrack) transport into the harbour from Jurien Bay is in progress and an operational trial will take place over winter, aimed at preventing wrack from entering the harbour.

In addition, the collection of oceanographic data as part of ongoing investigations into environmental issues in the local area continues.

  Project status

Dredging over the 2016-17 summer period removed 62,000m3 of material from the harbour entrance channel and sand trap areas, and seaward of the northern breakwater.

An operational trial to test the effectiveness of a 'bubble curtain' in acting as a barrier to floating wrack will be undertaken over the 2018 winter.

  About the project

The Department of Transport (DoT) is working to develop and implement strategies to address ongoing environmental issues in the Jurien Bay Boat Harbour.

Computer modelling to evaluate options for management and possible structural modification is in progress. The modelling is based on the extensive dataset on metocean and environmental conditions collected by DoT in recent years.

Decomposing wrack contributes to poor water quality in the harbour and DoT is trialing the use of a 'bubble curtain' this winter. The 'bubble curtain' aims to create a temporary barrier to floating wrack as it approaches the harbour in stormy weather.

Image of Jurien Bay - bubble curtain

Figure 1: Jurien Bay Boat Harbour bubble curtain trial location.

In May DoT will install and anchor a line of tubing to the seafloor between the two breakwaters. With compressed air pumped through the tubing, bubbles will escape through a series of holes and rise to the surface. The trial will operate during storm events and the expectation is the wall of streaming bubbles will generate currents that re-direct floating wrack preventing it from floating into the harbour during northerly conditions.

The trial will monitor the effectiveness of the bubble curtain at keeping wrack out of the harbour; sand ingress may also be reduced. Temporary Notice to Mariners 2018-76 was in place for the duration of the trial.

  History of the project

Jurien Bay Boat Harbour landscape image
Jurien Bay Boat Harbour aerial image

Figure 2 (above): Jurien Bay Boat Harbour.

Jurien Bay Boat Harbour opened in 1988 and the facility has a history of problematic seagrass wrack and sand accumulation that is contributing to water quality issues. Previous initiatives to address these issues have included weed trawling and maintenance dredging within the harbour.

A wrack trawling exercise in late 2013 was successful in addressing navigation problems and subsequent to that water quality improved. A further round of pre-emptive wrack trawling of the harbour entrance was completed in July 2014.

DoT completed sand excavation works in September 2014, to remove over 8000 m³ sand from inside the harbour.

Maintenance dredging programs were undertaken in 2015-16 and 2016-17 to deliver an improved harbour environment and to restore navigational depths in the entrance channel. Over the two campaigns approximately 140,000m3 of sand and wrack were removed from the harbour and adjacent Jurien Bay waters.

Figure 3 (right): Jurien Bay.

  Investigative study and data collection

Recent data collection and environmental studies

The Department of Transport undertook extensive data collection in 2014-17. The data set included:

Metocean data

  • A directional wave rider buoy deployed in Jurien Bay at a depth of 42 m to measure off shore wave parameters including wave height, period and direction.
  • Three acoustic wave and current devices (AWACs) were in placed outside the harbour to measure inshore waves and currents. AWACs record current speed and direction at different levels of the water column and also record wave parameters.
  • A current meter (Aquadopp) was located in the harbour entrance to measure current speed and direction at different levels in the water column.
  • Three pressure sensors were mounted in the harbour basin close to the harbour bed to measure water levels at 1 second intervals. The data assisted investigations into long-period wave condition in the harbour and is also used to validate numerical modelling.
  • A tide gauge is installed in the harbour and measures water levels every 5 minutes.

Photo monitoring

  • Regular aerial photography of the harbour and adjacent beaches.
  • Fixed point telemetered photography (from 2017).

Wind direction and speed

  • An anemometer (wind data station) was been installed to better understand weather associated with seagrass and sand transport at the harbour.

Surveys

  • Regular hydrographic surveys were undertaken to monitor seabed changes.

Wrack investigations

In addition to the data set collection a university study into the impact of wrack degradation on the water quality of Jurien Bay Boat Harbour was undertaken in 2016 and 2017. More is now known about wrack transport into the harbour including when the largest masses of wrack arrive, its composition, the impact of wrack age on decomposition rates and the subsequent demand for the consumption of dissolved oxygen from the water column. All these factors impact on the environmental health of the harbour.

Current data collection

DoT actively monitors events and changes in the harbour and undertakes and continues its data collection program. Tide and offshore wave data monitoring equipment continue to provide information on local conditions including wind, waves, ocean currents and water levels. Current instrumentation includes:

  • Wave buoy deployed offshore in Jurien Bay.
  • Two AWACs in the nearshore marine environment.
  • Current meter in the nearshore marine environment.
  • Tide gauge measures water levels in the harbour.
  • Water quality monitoring in the harbour.
  • Hydrographic surveys in the Jurien Bay Boat Harbour and adjacent, nearshore areas.
  • Site photographic records from fixed time lapse cameras and regular aerial photography.
PROJ_P_Jurien_Bay_study_data_collection.pdf icon Jurien Bay Boat Harbour study and data collection Kb

  Next steps

Computer modelling is being undertaken to identify coastal processes, seagrass wrack and sand movement, and events contributing to poor water quality outcomes.

A winter trial of a 'bubble curtain' to evaluate its effectiveness as an operations management tool will be implemented.

  Coastal infrastructure project contact list

Service Type Suburb Business Name Phone number Phone number (secondary) Fax Pre-booking required Business Hours Email Street address Postal address Business Type Comments
Coastal infrastructure project Bandy Creek Weir (Coastal infrastructure project) (08) 9435 7833 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) bandycreekweir@transport.wa.gov.au WA 6450 WA Department of Transport
Coastal infrastructure project Beadon Creek (Onslow) maritime facility (Coastal infrastructure project) (08) 9435 7676 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) WA Department of Transport Regional Facilities Coordinator
Coastal infrastructure project Broome Boating Facility (Coastal infrastructure project) (08) 9216 8240 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) james.holder@transport.wa.gov.au WA WA Department of Transport James Holder, Manager Maritime Projects
Coastal infrastructure project Burswood Public Jetty (Coastal infrastructure project) (08) 9435 7613 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) michael.maslin@transport.wa.gov.au WA WA Department of Transport Michael Maslin, Project Manager
Coastal infrastructure project Casuarina Boat Harbour (Coastal infrastructure project) (08) 9435 7539 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) casuarinaharbourupgrade@transport.wa.gov.au WA WA Department of Transport Dilhan Wijesinghe, Project Manager
Coastal infrastructure project Denham Maritime Facility upgrades (Coastal infrastructure project) (08) 9435 7613 No denhamforeshore.info@transport.wa.gov.au WA WA Department of Transport Michael Maslin, Project Manager
Coastal infrastructure project Fishery Beach (Bremer Bay) boat ramp protection (Coastal infrastructure project) (08) 9435 7613 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) michael.maslin@transport.wa.gov.au WA WA Department of Transport Michael Maslin, Project Manager
Coastal infrastructure project Fremantle FBH Jetty 2 redevelopment (Coastal infrastructure project) (08) 9435 7546 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) francois.sauzier@transport.wa.gov.au WA WA Department of Transport Francois Sauzier, Project Manager
Coastal infrastructure project Hillarys Boat Harbour upgrade (Coastal infrastructure project) (08) 9435 7546 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) francois.sauzier@transport.wa.gov.au WA WA Department of Transport Francois Sauzier, Project Manager
Coastal infrastructure project Jurien Bay Boat Harbour (Coastal infrastructure project) (08) 9435 7559 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) jurienboatharbour.info@transport.wa.gov.au WA WA Department of Transport James Holder, Manager Maritime Projects
Coastal infrastructure project Port Geographe reconfiguration (Coastal infrastructure project) 1300 660 815 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) portgeographe.Info@transport.wa.gov.au P.O. Box Box C102, Perth WA 6839 Department of Transport Justin Fifield, Project Manager
Coastal infrastructure project Two Rocks Marina upgrade (Coastal infrastructure project) (08) 9435 7833 No Monday to Friday 8:00 am until 5:00 pm. (excludes public holidays) tworocksmarina@transport.wa.gov.au WA WA Department of Transport Anna Kelderman, Project Manager

  Jurien Bay Boat Harbour project: Documents

 

Page last updated: Tue Nov 6 2018 1:25:32 PM