- Landscaping Objectives
- Landscape Design
- Recycling Landfill
- The Wetlands (Barker Inlet, Range and Magazine Creek)
- Environmental Achievements
- Environmental Assessment Report
Protecting the environment
The Port River Expressway has proven to be one of the most environmentally complex and challenging road projects in South Australia's history.
The project is unlike any other due to its geotechnical and environmental elements, which has meant respect for the environment has guided every aspect of planning and construction activities.
The main objective of the Stage 1 landscape design was to ensure that it created a unique, safe and attractive experience for road users. The expressway was constructed on approximately two metres of fill material, which provides a raised platform from which to view the landscape.
The landscape has been transformed into an open native woodland featuring large stands of native grasses, which is a dramatic change from the existing landscape of industrial fill and vacant allotments. Low shrubs and cluster tree-planting supports the continuation of views over the wetlands and tidal landscapes to the north. The landscape also provides vantage points to view the surrounding features, including the wetlands and views towards the Port.
The landscape design of the expressway acknowledges the importance of long-term improvement and care for the environment. The design:
- used existing vegetation where possible.
- ensured that remnant vegetation areas were protected during construction.
- used seed collected from local sources, including remnant roadside vegetation, to be used for new planting.
- used native plant species which occur in the Port Adelaide area, and limited the use of exotic species.
More than 300 000 trees, shrubs and native grasses have been planted along Stage 1 of the expressway. Local species were used as they are suited to the local conditions and environment and assist in maintaining a native vegetation theme. The native species chosen have all been raised successfully in commercial nurseries and were able to be either locally sourced or grown specifically for the project. Most trees have guards as protection from hares and rabbits.
- One of the main challenges of Stage 1 of the project was managing the existing waste and fill materials located on the site in an environmentally sustainable way.
- The close proximity of the Port River Expressway to recycling industries enabled the contractor to use recycled material for 1.7 million tonnes of fill required for this project - equivalent to 75 000 fully loaded semi trailers. This was used to meet the Coast Protection Board's requirement that the road level be three metres above sea level.
- Approximately fifty per cent of the site was covered with up to two metres of uncontrolled fill which has been deposited along the alignment over the past 100 years. Much of this fill consisted of demolition material such as bricks, concrete and rubble. An area of 300 metres in length contained household rubbish, which had been buried in pits up to four metres below the original ground surface. Another area, 400 metres in length, contained demolition material also buried in pits.
- A significant amount of resources were recovered and re-used from over 94 000 tonnes of waste items during the construction of Stage 1, which otherwise would have been removed from the site. This waste was processed and combined with better quality recycled material to build the foundation for the expressway. Larger waste items such as tyres were recovered by machinery, while smaller waste items such as timber, plastic, rubber and metal were removed by hand so they could be taken to the appropriate recycling depots for further reuse.
Breaking up recycled concrete during construction of Stage 1
The Port River Expressway project has highlighted how recycled materials can be successfully incorporated into a roadworks project with no compromise to the final product, subsequently preventing the need to quarry new materials, saving resources for future generations.
Overview of Barker Inlet Wetlands
Stage 1 of the Port River Expressway is located 12 kilometres northwest of Adelaide, near Wingfield in an area which is characterised by swampy, tidal samphire vegetation. This area includes three constructed storm water wetlands: the Barker Inlet Wetlands, Range Wetlands and Magazine Creek Wetlands.
All three wetlands systems discharge into the mangrove estuary of North Arm Creek, which flows into the Barker Inlet Aquatic Reserve. This reserve supports the world's most southern stand of the grey mangrove, Avicennia Marina, and acts as a major fish spawning and nursery site. The wetlands are fed by stormwater drainage systems, carrying urban and industrial stormwater runoff from a catchment of about 4500 hectares extending as far away as North Adelaide.
The wetlands have been constructed to:
- improve storm water quality
- improve visual amenity and provide recreational opportunities
- increase habitat values and habitat diversity
- provide an opportunity to harvest and reuse storm water.
The department paid careful attention to managing water quality in the wetlands during the construction of Stage 1 of the Port River Expressway and continues to do so during its operation. Legal requirements guiding this issue are set out in the Environment Protection Act, 1993 and the Water Resources Act, 1997. In addition, strict procedures were developed for the contractor to carry out works to prevent pollution of surface, ground and marine waters. These prevention measures included weekly water quality monitoring at eight locations along the Stage 1 alignment. This monitoring measured salinity, pH, turbidity and water colour.
The wetlands are at the end of five major drainage lines: Jenkins Street Drain, Eastern Parade Drain, North Arm Drain, Hanson Road Drain and South Road Drain (see diagram below).
The drainage design included the following measures to manage any spills during construction and operation of the expressway before reaching the wetlands:
- Using existing tidal gates in the Barker Inlet Wetlands to isolate spills.
- Developing a management plan to deal with spills including the provision of spill kits and sand bags.
Location of eight water quality monitoring points, Stage 1 roadworks.
CASE Earth Awards
In late June 2006, the department's contractor for Stage 1 of the Port River Expressway, Bardavcol (in conjunction with Tonkin) received two South Australian 2006 CASE Earth Awards for the environmental and construction achievements of Stage 1. The awards recognise and reward environmental excellence, best practice and innovation in the field of environmental management of civil construction and related projects.
More than 1.7 million tonnes of recycled material was used in the construction of Stage 1 of the Port River Expressway, which proved to be one of the most environmentally complex and challenging road projects in South Australia's history. This use of recycled material was recognised by the state awards with a win for the department in the category of 'Environmental Excellence' for projects over $15 million. In addition, the Construction Excellence Award for projects over $15 million was awarded to the department for the quality of construction work on Stage 1 of the Port River Expressway.
The department, Bardavcol and Tonkin were also finalists in the National 2006 Case Earth Awards.
Commended for environmental engineering
A commendation was awarded to Transport Services Division (formerly Transport SA) in partnership with Tonkin Consulting and Bardavcol Pty Ltd in October 2004, for their successful management of site contamination for Stage 1 of the Port River Expressway project.
The commendation was won in the Environmental Engineering category of the South Australia Division Engineering Excellence Awards for Engineers Australia.
The department and its project partners received the commendation award in recognition of their innovative and environmentally friendly management of contaminated material on the Port River Expressway - Stage 1 site.
The Port River Expressway Stage 1 team from the department, Tonkin Consulting and Bardavcol Pty. Ltd.
From left to right:
- Adrian Smith, Division President, Engineers Australia, South Australia Division.
- Rene Arens, Principal Consultant, Tonkin Consulting.
- Peter Rusk, Environment Officer, Bardavcol Pty Ltd.
- Adam Cheeseman, Sponsor representative from Bluescope Steel.
- Jeff Goode, Major Projects Co-ordinator, Department of Planning, Transport and Infrastructure.
- Glenn Passfield, Senior Engineer, Tonkin Consulting.
Environmental Assessment Report (released on November 2000)
Supplement to the Environmental Report (released on July 2001)
This document includes summaries and descriptions of the:
- project and its history
- need for new road and rail arrangements and the projected traffic flows
- alternatives to the proposed highway and rail connections
- existing biophysical environment
- existing social environment, including Aboriginal and European cultural matters
- commercial activities and land uses in the vicinity of the new highway
- potential impacts of the project on the:
- biological environment
- physical environment (including stormwater management)
- social environment
- commercial activities, including tourism
- methods of minimising adverse impacts and enhancing positive impacts.