At the recent General Meeting of the City of Marion, Elected Members resolved to confirm their decision to build the suspension bridges across Grey Road Gully and Kurnabinna Gully at Hallett Cove.

Grey Road Gully and Kurnabinna Gully remain the final sections of the Coastal Walkway improvement project to be completed. The $1.126 million Field River upgrade was officially opened in April 2022.

For environmental, accessibility and financial reasons, Council resolved late last year to proceed with suspension bridge designs rather than rebuilding the stairs.

That decision was reviewed by various consultants in recent months, including an environmental assessment report and a Prudential Report prepared in accordance with Section 48 of the Local Government Act 1999.

Taking into consideration these reports, Council has accepted the advice that building the suspension bridges will minimise adverse environmental impacts on the locality and improve accessibility.

The bridges will also reduce risk during construction and will be several hundred thousand dollars more cost-effective when considering the “whole of life” costs of the project.

It has been noted that global material shortages, increased labour costs and recent CPI increases have significantly increased the cost of installing the bridges.

The same cost pressures would be applicable to the stairs option but ascertaining accurate tender comparisons would result in additional design costs and further delays to the project.

Environmental considerations

Earlier this year Council commissioned a consultant to do an environmental and accessibility assessment. The Report concluded that the suspension bridges improved accessibility, minimised environmental impacts and reduced the risks and the costs involved in construction.

The bridges would require only eight footings instead of the hundreds required to install the boardwalk.

The bridges would also negate the need to build temporary access tracks and install significant temporary works to allow the construction of the stairs given the complex terrain. All these factors would have had an impact on the local flora and fauna.

Accessibility considerations

The current boardwalk is only accessible to the physically able and is classed as a Grade 3 walking trail because of the difficulty of the terrain. While this grade may promote fitness aspects, it may discourage the general community from using it.

The inclusion of a bridge in lieu of the boardwalk to the gullies reduces the difficulty of the entire boardwalk by eliminating the need to traverse the gullies and creates a more appealing and inclusive asset for Council to attract the broader community. It would also provide further access to portions of the coastal walkway for people of all fitness abilities to enjoy the coastline views safely.

Community consultation

Council has considered feedback from the community and has incorporated these in the final design documentation such as the reduction in scale of the suspension bridges to minimise visual impact.

The pillar heights will be reduced from the original concept designs and the length of the bridges has been reduced from 50m to around 40m. The bridges will be constructed from galvanised steel, supported by pillars connected by galvanised steel wire ropes, with fibre reinforced plastic enviro walk mini-mesh decking.

Financial considerations

Global material shortages, increased labour costs and recent CPI increases have significantly increased the cost of installing the bridges from initial quotes a year ago. However, Council has been advised that the suspension bridges would be several hundred thousand dollars more cost-effective than replacing the stairs, considering "whole of life" costs and the fact that the cost of materials and labour for reinstating the stairs would also have escalated in the past year.

The bridges, including contingencies and professional costs, will cost $8 million. The original budget for the project was $4.88 million, including a $2.44 million contribution from the State Government. This leaves a funding gap of $4.57 million which Council plans to incorporate in the 2022/23 Annual Business Plan.

Construction information

It is anticipated preliminary works will be commencing in late June 2022.

Working hours will be 7am to 5pm, Monday to Friday, with construction works expected to be completed in June 2023. As with any construction works, on occasions,