Environmental Footprint

Reduced the environmental footprint for our business

Image: Environemental Footprint objective.PNG 


The Issue

Human-caused environmental pressures are a serious global sustainability issue. Much of Western Australia’s environmental heritage is of significant importance from a global perspective and the interface the environment has with our road asset and projects is ever present.

For further information on the environmental context of road reserves can be found on our  environment page.

The modern world is considered to be experiencing a ‘sixth great extinction’ of animal species, or at least it is not far from it.  The rate of extinction for species in the 20th century was up to 100 times higher than it would have been without human impact.  Species loss is an indication that our ecosystems are not in balance and this threatens the ecosystem services on which we depend.  It is expected that road infrastructure and road transport will also be faced with many challenges over the coming decades from an environmental perspective.

As an infrastructure agency and with ever increasing freight tasks and changing vehicle types, we are continually being asked to provide more road space for wider, heavier and greater volumes of vehicles, or provide more space for safety reasons.  This leads to greater demands for natural resources and compounds environmental pressures (eg. more material use and land clearing).  In our current environment, not upgrading our roads means we risk stifling economic and community development, particularly in our regional and remote areas.  In short, the ever growing need for transport is compounding some of the current environmental pressures such as use of non-renewable materials and changes in land use.



What we're doing

Land use

We recognise that the operations of the state road network, if not undertaken with care and responsibility, has the potential to cause negative environmental impacts to Western Australia’s unique environment.  The biodiversity of our state is widely recognised as unique and special.  To ensure our sustainable approach to land use we do the following:

Environmental Management

We manage our operations using a systematic approach in which all of our activities are screened for potential environmental impacts. Environmental impacts are the consequences of implementing an action and can include the positive or negative changes to the:

  • physical (eg. land, water and air);
  • biological (eg. flora and fauna);
  • cultural (eg. Aboriginal and European heritage and culture);
  • socio-economic; and
  • human-health values, of our environment.

We also operate on a hierarchy of avoid, minimise, reduce and offset our environmental impacts.  This means that when an EIA identifies that an action is likely to have a negative environmental impact we seek to firstly avoid, minimise, reduce and then offset our environmental impacts.  This is achieved primarily through changes in scope and design, and the development and implementation of an Environmental Management Plan and an Offset Proposal.

Revegetation and Landscaping

Revegetation and landscaping is standard practice on our projects to counteract the impacts of vegetation clearing and/or soil disturbance and to help retain and enhance the environmental values of roadsides. We have a proud history of undertaking revegetation, over many years, with awards for innovative revegetation along roadsides dating back to the 1980’s.

The videos below provide examples of how we undertake revegetation works as part of road projects.

Visit our Environment page for detailed information.

Energy & Emissions

The development, operation and use of a road network consumes energy and generates emissions in numerous forms. The predominant impacts from energy and emissions fall outside of our direct control from the use of the road network itself. Road transport makes up 15 per cent of Australia’s total emissions and has been the highest growing source of emissions since 1990 (BITRE 2015). We estimate that the road network generates carbon emissions of a rate of 295.6 t COX2 per million vehicle kilometres travelled (MKVT). In 2016-17 MVKT was 29,434 and thus emissions were approximately 8.7 Mt CO2-e from use of the road network. We value chain for emissions and energy can be categorised as follows: 

 Image: Sustainability - Footprint value chain image.PNG

Our Administration Facilities and Network Asset Operations are under our direct control. Our Asset Maintenance and Asset Upgrades/Construction are delivered under contract arrangements where the responsibility of energy consumption and emission sources are delegated to the contractor. For Road Network Use we have minor influence on energy use and emissions but recognise we have a role to play and opportunities to influence better outcomes overall.

Emissions from direct operations activities                                                                                                                                    Top

We have a carbon reduction target of 5 per cent of 2010 carbon emissions by 2020 with a stretch target reduction of 15 per cent through improving energy efficiency.  The target is largely focused on upgrading current electrical assets to be energy efficient.

Effort will also go into reducing the expansion of certain asset types, such as traffic signals which tends to be utilised as a general congestion management option. We have adopted a policy that alternative treatments such as roundabouts or modified intersections to provide acceleration lanes will be preferred over traffic signalisation, as they provide significant road safety benefits and in most cases, assist with reducing congestion.

Our total emissions across our facilities during 2016-17 were 23,894 tCO2, achieving our target which was to be below 29,743 tCO2.

The major action under Carbon Reduction Plan progressed during 2016-17 was a trial of highway standard LED street lights is being implemented on the Mitchell Freeway Extension. 330 LED lights have replaced the 292 HPS street lights. It is estimated that there will be a 20 per cent reduction in on-going energy use or an annual saving of 56 tCO2.

Project and maintenance activities

We’re looking to expand our focus for emissions reductions to manage the emissions generated on our projects and maintenance activities. We encourage our project partners to reduce emissions from their activities through energy efficiency, the use of renewable or alternate energy sources and use of materials with lower embodied energy.

In collaboration with interstate and overseas road authorities we have helped develop a common whole-of-life methodology for assessing the greenhouse footprint of road projects, the Carbon Gauge Greenhouse Gas Calculator Tool. It is anticipated that the introduction of the Infrastructure Sustainability framework for our major projects will see a greenhouse gas emissions reporting regime implemented.


Impacts to air quality from projects or network operations

We adhere to legislated requirements in regards to managing air quality from its activities. Refer our Environment page for further information on how we manage our environmental impacts.

Discharges to water

Our operations results in very little discharge of water. In WA, the discharge of water is regulated through the Environmental Protection Act 1986 and the Rights in Water and Irrigation Act (1914) and in the event we were required to discharge water, it would obtain the appropriate approvals prior to discharge.

Water run-off

Where there are direct linkages between storm-water and sensitive receivers, pollutant traps have been installed to prevent adverse impacts to the wetlands. Locations include:

  • Lake Gwelup from Karrinyup Road;
  • Swan River from Reid Highway; and Great Northern Highway;
  • Swan River from ~20 outfalls along Kwinana Freeway;
  • Canning River from Leach Highway;
  • Booragoon Lake from Leach Highway; and
  • Quenda Wetland from South Street.

The treatments include interception of gross pollutants/rubbish, sediment, nutrients, heavy metals and hydrocarbons. Apart from Kwinana Freeway outfalls, the above outfalls also have the capacity to trap hydrocarbon spillages up to 19000 L.

There are several sites where a pollutant trap system is being designed to prevent potentially significant impacts, though these areas have not been confirmed as being “significantly affected”. Locations include Bull Creek from Leach Highway (one outfall near Bull Creek Drive) and Canning River from Canning Highway (one outfall west of Canning Bridge).

The Southern Lake at the Narrows Interchange is an artificial sump that collects storm-water from Mitchell Freeway and Mounts Bay Road, contains nutrient-rich sludge, heavy metals and hydrocarbons, and is directly connected to the Swan River. However, this sludge is being removed, and there is a weir structure that retains water and hence pollutants within the Lake.

For other road runoff, local sumps, compensating basins, infiltration basins and swales have been specially constructed to process storm-water, separating it from sensitive water receivers.

Resources & Waste

Water                                                                                                                                                                                                     Top

Water is a precious resource and our State continues to experience the effects of a drying climate. We encourage practices that reduce our impact on water sources including improving water efficiency and overall water use, utilising recycled water and avoiding the use of potable water.

For our buildings and accommodations we require water efficient WELS rated plumbing fixtures and any landscaping is to be water wise. We actively manage our water use to minimise any impacts from water leaks should they occur.

Within construction projects and for operations, we prioritise the use of non-potable water over scheme water to ease the burden of water scarcity within the communities we work in. When we are required to utilise ground water reserves we adhere to our licensing obligations to access this water. WA has a rigorous environmental impact assessment process which assesses the impact of water withdrawal/usage on a water source. The withdrawal of water that is likely to result in a significant impact on a water source would not be considered to be environmentally acceptable under the Environmental Protection Act 1986 and would not receive a license to abstract water under the Rights in Water and Irrigation Act (1914).

Information regarding water abstraction and the licences required can be obtained from Department of Water (DoW) .

Road Building Materials

Natural materials are crucial in road building, so we encourage our project partners to recycle and reuse materials and use recycled and ‘environmentally labelled’ materials in road construction and other activities.

When obtaining road building materials we endeavour to avoid clearing natural vegetation, particularly high value vegetation. On-site materials unsuitable for use in road construction is used, as appropriate, for rehabilitating areas where road building materials have been obtained from.

The briefing note on our recycling practice provides guidance on current accepted recycling practice. Specifications for the use of recycled road building materials can be found on the Standards and technical website. Those materials include the use of 100 per cent glass cullet in earthworks which was adopted in 2015-16.

We research the use of waste materials such as recycled construction and demolition waste. Our current research activities include:

  • Monitoring and evaluation of crushed recycled concrete pavement trial section on Kwinana Freeway; 
  • Characterisation of reclaimed asphalt pavement (RAP) to improve the performance of asphalt mixes that incorporate RAP;
  • Scoping project to develop crumbed rubber modified asphalt technology;
  • Evaluation of the performance of crumbed rubber modified spray seal binder manufactured in Fremantle and carted to Leonora – Laverton;
  • Desktop review of future pavement technologies such as recycled plastic in asphalt; and
  • Metropolitan Region rehabilitated two section of Thomas Road in 2015-16 by bituminous stabilisation (1- emulsion and 1- foamed bitumen) to treat the pavement and also to evaluate the processes as a method of pavement reuse for future rehabilitation works.

Traffic signals, Signs & Pavement Markings

Reducing sign clutter or the over proliferation of signs, and over dependence on types of pavement marking like median infill contributes to using less resources. We will continuously review existing standards and practices to reduce the amount of unnecessary signs and pavement marking across the network where it is safe to do so.

Additionally, a process to identify potential sites for traffic signal removal and installation of alternate shared space treatments is currently under development. This will have flow on benefits for reducing our direct energy consumption and greenhouse gas emissions.

Roadside Waste                                                                                                                                                                                   Top

Roadside waste is a strategic sustainability issue for us and continues to burden our regions requiring ever-increasing attention to control.  For many years illegal dumping of waste items, which are potentially recyclable such as tyres and building waste, has affected our road reserves. We encourage our community and industry to become involved in developing initiatives and solutions to target this issue.

We are collaborating with key stakeholders, interested parties and community groups to implement a consistent litter management approach for the state whilst taking into account individual regional requirements. A State Wide Litter Plan has been developed, targeting five key aspects across Western Australia:

  • Roadside litter collection;
  • Rest Area Management;
  • Illegal dumping;
  • Unsecured Loads; and
  • Abandoned vehicles.

The primary objectives of this strategic initiative is to educate road users to take their litter with them wherever feasible or practical and reduce the occurrence of litter and illegal dumping through greater public awareness of the issue, increased community buy-in and participation in litter reduction programs and behaviours.

Renewable Energy

We support the use of renewable energy where it is practical to install within our electrical assets regardless of the fact that it may not be a first order priority for emissions reduction. So far, assets that we’ve used renewable energy for include bus shelters, remote road lighting, emergency telephones and school crossing warning signs. We have also installed systems on our offices and staff housing. We will trial the use of renewable energy systems on our site offices.


The Numbers

For details on our Environmental Footprint performance please refer to the Environmental Management section of our Annual Report.
Data included in the annual report includes:

  • Greenhouse Gas Emissions & Energy consumption;
  • Area of land cleared, revegetated and offset;
  • Water use; and
  • Materials use & recycling.


Case Study

Northlink WA Southern Section emissions standards

NorthLink WA is undertaking a sustainability initiative to report plant emissions during construction. We require NorthLink WA contractors to report their plant emissions monthly including plant and vehicle fleet used during construction. NorthLink WA has specified high fuel efficiency construction equipment to reduce diesel consumption and pollution. All diesel heavy duty vehicles need to comply with the ADR80/03 specification and light vehicles need to comply with the Euro 4 or higher.

NorthLink WA southern section is midway through construction and can report a compliant fleet would result in an improvement of approximately 1,200 tonnes of CO2-e during construction, recently quantified by the eTool Life-cycle Assessment. 


Modified: 11 Jan 2019