Port Geographe reconfiguration (project)

The original coastal rock structures at Port Geographe have been reconfigured to improve environmental and amenity outcomes for the coast and community.

  Status: completed - on-going monitoring

The construction work associated with the Port Geographe Reconfiguration Project was completed in May 2015. Further information on these construction works can be found under the headings below.

The Department of Transport undertakes ongoing coastal monitoring of the area as it undergoes a period of natural adjustment to the new configuration.

  Current and future management

Following completion of these major construction works the project has moved into the maintenance and operations phase. Specifically, the Department of Transport has ongoing responsibility for the performance of the reconfigured coastal structures, and provides coastal monitoring, management and maintenance of the Port Geographe entrance channel, and adjacent western and Wonnerup beaches.

Environmental and operational management plans guide responses to sand and seagrass wrack movement along the Port Geographe foreshore.

The Department of Transport implements supporting contracts for ongoing engineering advice, inspections and management of the project area. Monitoring techniques include regular:

  • Hydrographic and land surveys.
  • Site inspections.
  • Water quality monitoring.
  • Photographic monitoring.

Management responses to sand and wrack movement may include wrack pushing, dredging and bypassing.

Environmental Management and Compliance Reporting

In November 2014 the Office of the Environmental Protection Authority issued Ministerial Statement 990 to identify and guide the Department of Transport's coastal management obligations in the management of the reconfigured coastal structures, entrance channel and adjacent beaches at Port Geographe. In response a Port Geographe Coastal Structures Environmental Monitoring and Management Plan (EMMP) was developed to align with the environmental requirements in Statement 990.

The Department of Transport is required to provide an annual report (Statement of Compliance) on the extent of compliance with the conditions in Ministerial Statement 990. Requirements guiding each year's Statement of Compliance reporting are provided in the approved Compliance Assessment Plan.

MAC_P_PortGeo_CoastalStructures_EMMP.pdf icon Port Geographe coastal structures: Environmental Monitoring and Management Plan (EMMP) Kb
MAC_P_PortGeoComplianceAssessPlan.pdf icon Port Geographe coastal structures: Compliance Assessment Plan - Ministerial Statement 990 Kb
MAC_P_PortGeoStatementofCompliance.pdf icon Port Geographe coastal structures: Statement of Compliance (2014/2015) Kb
MAC_P_PortGeoStatementofCompliance_15_16.pdf icon Port Geographe coastal structures: Statement of Compliance (2015/2016) Kb

  Monitoring and performance in 2016

Following the completion of major construction works in May 2015, the Department of Transport has been undertaking ongoing coastal monitoring in the project area known as the Port Geographe Coastal Management Area (PGCMA). The PGCMA incorporates the beach area west of Port Geographe ('western beach'), the entrance channel and Wonnerup beach.

PGCMA sketch - Port Geographe

The Department of Transport PGCMA as indicated by the red boundary.

The Department of Transport has been continuing to undertake ongoing coastal monitoring in the Port Geographe Coastal Management Area (PGCMA). The 2016 winter marked the second winter since completion of the reconfigured coastal structures and associated sand nourishment works on the western beach in December 2014. The performance of the reconfigured structures in 2015 was exceptional, with the required coastal maintenance works limited to the placement of additional sand on Wonnerup beach. Whilst the 2016 winter was more severe (than 2015) the overall performance of the reconfigured structures has continued to meet or exceed expectations.

Western Beach

The establishment of a wide Western Beach, closely aligned to the final reconfiguration design requirements, was completed in time for the 2014-2015 summer. Since this time no further works on the Western Beach have been undertaken. The subsequent storm systems have naturally altered the beach profiles and, despite a more severe winter being experienced in 2016, the ability of the reconfigured breakwater to naturally dissipate seagrass wrack off the beach following an accumulation event was again demonstrated. (View gallery in separate section below.)

In addition, this winter demonstrated the ability of the reconfigured breakwater to also naturally bypass material in line with the original design intent. Storm events, resulting in a significant natural reduction in the volume of wrack on the Western Beach, were observed into mid-October such that by November 2016 the volume of seagrass wrack remaining on the beach was ~15,000m3 and by the end of 2016 the volume of seagrass wrack remaining on the beach was less than ~12,000m3. Although this represents an increase in seagrass wrack volume compared to the performance at the same time in 2015, it is a substantial improvement over previous seagrass volumes requiring removal associated with the earlier configuration. Previous seagrass wrack accumulations were estimated to be ~125,000m³, ~115,000m³ and ~150,000m³ in 2013, 2012 and 2011 respectively.

Marina Entrance Channel Area

Although the comparably more severe winter in 2016 demonstrated the ability of the reconfigured breakwater to naturally bypass material, this process has also affected the marina entrance channel. Hydrographic surveys of the entrance channel have shown there has been an accumulation of material within the area. Whilst the hydrodynamics of the reconfigured entrance channel have previously demonstrated the ability for natural self-flushing, continued hydrographic surveys undertaken by the Department of Transport have shown the accumulation is to the point where maintenance dredging was considered necessary.

For this reason the maintenance dredging works in the entrance channel commenced in early December 2016. Further operational details of this current maintenance dredging campaign can be viewed in Temporary Notice to Mariners 2016-103 published for these works as per the following link: http://www.transport.wa.gov.au/imarine/south-west-tntm.asp.

Wonnerup

Within the PGCMA, Wonnerup beach extends for approximately one kilometre east of the eastern seawall (revetment). Wonnerup beach in 2016 showed a very similar performance pattern to last year. Specifically, survey results on Wonnerup beach have shown an increase in sand (accretion) over the calmer 'summer' months (December 2015 to April 2016) but a decrease in sand (erosion) over the stormy 'winter' months (May 2016 to September 2016). Even though the monitoring results for 2016 showed that overall there has been a net erosion of material at Wonnerup, it was very encouraging that at the end of the stormy 'winter' months the beach was still providing good amenity. (View gallery in separate section below.)

To supplement beach condition prior to the 2017 winter, a sand nourishment campaign will be undertaken in autumn 2017. This will involve the importation of beach quality sand sourced from a local sand supply and placed on Wonnerup beach. These Wonnerup beach sand nourishment works will be completed prior to the 2017 winter.

Overview

Notwithstanding the encouraging outcomes in 2016, annual performance variations of the reconfigured coastal structures (with regard to seagrass and sand) continue to be monitored. Future maintenance works will continue to respond to seasonal variations and the results of ongoing monitoring undertaken by the Department of Transport (hydrographic surveys, land surveys, site inspections and photography).

  Image gallery: Western Beach (monitoring and performance in 2016)

  Image gallery: Western Beach (monitoring and performance in 2015)

  Image gallery: Wonnerup Beach (monitoring and performance in 2016)

  Image gallery: Wonnerup Beach (monitoring and performance in 2015)

  Project overview

Port Geographe is a privately developed and partially completed marina and canal development near Busselton. The original coastal structures, built as part of the initial marina and canal development in the 1990s, caused serious seagrass wrack accumulation on the western side of the development and amplified coastal erosion on the adjacent eastern coast.

Years of community consultation and scientific research into seagrass and sediment movement in Geographe Bay confirmed a complete reconfiguration of the coastal structures was required to improve environmental outcomes for the Port Geographe foreshore.

On November 2012 the Minister for Transport announced $28.15 million in funding to undertake the Port Geographe Reconfiguration Project to remove the existing coastal structures and replace them with an improved, streamlined coastal alignment.

The reconfiguration of the coastal structures included the following:

  • Removal and recovery of the former rock breakwaters and groynes.
  • Construction of a new breakwater and seawall, realigning the foreshore and entrance channel.
  • Dredging of the new entrance channel.
  • Construction of a coastal lagoon.
  • Importing additional sand to establish new beach profiles.
  • Installation of a below ground bypassing pipeline to facilitate future maintenance operations with minimal disruption.
  • Extensive landscaping to transform the foreshore into an inviting recreational space for the community to enjoy.

Construction works commenced in July 2013 with the removal of the existing rock groynes. The significant breakwater works were completed in June 2014, followed by dredging and beach works completed by December 2014.

Landscaping to develop new community recreational spaces at Port Geographe was the final component of works for the Port Geographe Reconfiguration Project and this was completed in May 2015.

The primary objectives of this project were to bring about major benefits for the environment, local residents and the wider community. This was achieved by addressing environmental and health issues, and reducing ongoing annual coastal maintenance costs.

By allowing sand and seagrass to bypass the new coastal structures naturally, it is expected the reconfigured structures will reduce seagrass accumulation and beach erosion at Port Geographe to levels consistent with other coastal areas along Geographe Bay.

This will also provide the benefits of improved amenity and access to beaches.

External Link 16/11/2012: State Government funds Port Geographe solution

  Construction works

The major capital works associated with the Port Geographe Reconfiguration Project took place from July 2013 to May 2015.

In July 2013 WA Limestone and Italia Stone Group Joint Venture worked to reconfigure the rock structures, initially removing the old breakwater and groynes and constructing the new breakwaters, revetment and lagoon beach. The new entrance channel opened in March 2014 and the new rock structures were completed in June 2014.

Dredging was required to realign the entrance channel into the Port Geographe marina and canals, and to establish appropriate depths for navigation. CGC Dredging undertook these works and also undertook dredging for the foundations of the new breakwaters in coordination with the coastal structures work.

Coastal bypassing took place during the Port Geographe Reconfiguration Project. Busselton based contractor, VMS Contractors, removed and bypassed stranded seagrass wrack from the western beach. In addition, the western beach was widened and realigned to meet the design shoreline position for the new structural layout. Operations to renourish Wonnerup beach was completed in December 2014.

Capel based contractor South West Industrial Plastics (SWIP) installed a 650 metre buried pipeline to allow dredged material (including wrack) to be pumped from one side of the Port Geographe development to the other. Valves were also installed to permit flexibility in terms of both connection points in and discharge points out.

The realignment of the Port Geographe entrance channel required navigation aids to guide vessels through this new channel alignment. Transfield Services removed the previous navigation aids and installed a combination of both land based navigation aids and floating navigation aids to mark the new entrance channel.

Landscaping was the final major construction contract. These works were undertaken by Bunbury based landscaping contractor, LD Total. The landscaping works transformed the foreshore at Port Geographe into an attractive and inviting recreation space featuring sheltered picnic areas, a naturescape play area, a universal access boardwalk, exercise areas, meeting places and a network of multi-purpose pathways. The landscaping works, completed in May 2015, followed a careful assessment of the landscape, community consultation and endorsement by the City of Busselton.

MAC-P-PortGeo-ConstructionImages.pdf icon Port Geographe Reconfiguration Project: Construction images Kb
External Link 29/05/2015: Busselton welcomes new coastal venue
External Link 08/04/2015: Western foreshore opens at Port Geographe
External Link 09/10/2014: More beach sand for Port Geographe and Wonnerup
External Link 08/08/2014: Major boost to public space at Port Geographe
MAC_P_Pt_Geo_channel_opens_DoT_nav_warning.pdf icon 26/03/2014: New channel opens at Port Geographe Kb
Opens in a new window 28/06/2013: Work set to start on Port Geographe

  Image gallery: Changes recorded by aerial photographs (construction works)

  Investigations and design

The University of Western Australia (UWA), Edith Cowan University and modelling company DHI commenced investigating solutions to the coastal problems at Port Geographe in 2007 and UWA continued to fine tune the initial outcomes with its hydrodynamic, seagrass wrack and sediment modelling to verify the final engineering design as the best outcome for Port Geographe.

A Sediment and Seagrass Reference Group, representing coastal interests at Port Geographe, was set up to review design options and recommend the preferred concept.

The engineering plans for the redevelopment of the Port Geographe structures were developed by Worley Parsons coastal engineers. Additionally, physical modelling (tank testing) of the new coastal structures at Manly Hydraulics Laboratory in Sydney was utilised to optimise the design.

  Earlier seagrass and sediment studies

Initial research by UWA, Edith Cowan University and modelling company DHI researched and developed coupled hydrodynamic and seagrass modelling to develop and understanding of the dynamic coastal processes affecting the Port Geographe foreshore.

UWA expanded the first study to include sediment (sand) movement at Port Geographe. The 'Port Geographe Sand and Seagrass Wrack Modelling Study', confirmed the earlier recommendation that a reconfiguration of the coastal structures at Port Geographe was needed to alleviate problems of seagrass wrack accumulation, siltation and erosion.

Through the initial and subsequent studies a refined conceptual design was developed and community consultation review consolidated the recommendation. Studies providing the foundation of support for the reconfiguration are available at the links below.

MAC-R-PortGeo-SandSeagrassModelling.pdf icon Port Geographe sand and seagrass wrack modelling study, March 2011 Kb
MAC-R-PortGeo-SeagrassWrack-Synopsis.pdf icon Seagrass wrack dynamics in Geographe Bay WA, April 2010: Synopsis Kb
MAC-R-PortGeo-SeagrassWrack-Full.zip icon Seagrass wrack dynamics in Geographe Bay WA: April 2010 - Full (Archive) Kb

  Contact us

For any enquiries about the recently completed Port Geographe Reconfiguration Project or the ongoing maintenance works at Port Geographe please contact the Project Manager using the contact details below.

Street address Postal address Telephone Fax Email
Project Manager
Port Geographe
Department of Transport
Marine House, 1 Essex Street
Fremantle 6160, Western Australia
GPO Box C102,
Perth WA 6839
1300 660 815   Email

 

Page last updated: Wed Jun 7 2017 9:49:26 AM