NMR was committed to responsible environmental management during its activities of planning and implementing the Mandurah Line. Comprehensive environmental research and planning was an integral part of the project since planning began. As a result of this process significant changes were made to the alignment to preserve areas of high environmental value.

In 2002 the EPA set the level of assessment at Public Environmental Review (PER). In July 2003 the EPA released their report and recommendations to the Minister for the Environment. The Minister for the Environment granted approval for the proposal, subject to conditions, in November 2003.

As part of the PER approval, NMR was required to prepare a number of management plans to ensure that potential environmental impacts were identified and minimised as far as possible. These impacts include:

• Air quality
• Biodiversity 
• Bushland access 
• Flora and fauna 
• Heritage
• Landscaping and revegetation 
• Noise and vibration 
• Public consultation 
• Public risk and safety 
• Soil and groundwater contamination 
• Sustainability 
• Visual amenity and 
• Wetlands

Air Quality

Vehicle emissions account for a great deal of the air pollution in Perth. It is estimated that traffic in Perth will increase by 30 per cent in the next 20 years. Providing a viable alternative to the private vehicle in the form of a fast, comfortable and effective electric passenger rail service is one way to improve Perth’s current and future air quality. The railway generates negligible atmospheric emissions in the metropolitan area.

Biodiversity

NMR prepared a Biodiversity and Wetland Mitigation Plan which provided mitigation or compensation for the loss of environmental values caused by clearing for the project. Rehabilitation of 14 hectares of PTA owned land in Kwinana formed the main part of NMR’s mitigation package. The land has been transferred to the conservation estate. Changes to the rail alignment were also made in consultation with the Department of the Environment to provide better environmental outcomes and minimise clearing. NMRl salvaged 5,000 grass trees and 2,500 zamia palms for the railway alignment. The plants were used in landscaping works at the stations and also made available to local governments and environmental groups for use in rehabilitation projects.

Bushland Access

The introduction of a railway line always presents a management challenge to reconnect the newly separated areas on either side. This was particularly relevant in the areas from Leda to Mandurah. Combined access tracks for PTA railway maintenance, CALM park management and emergency services were constructed within the railway reserve, where practicable. Two heavy vehicle underpasses were also constructed – one in the Leda Nature Reserve and one in Karnup.

Flora and Fauna

Detailed flora surveys were completed along the route of the Mandurah Line. In total 231 species of flora were identified, 68 of them weeds. NMR commissioned botanists to carry out surveys of the Grand Spider Orchid population at the Murdoch Station site. It was determined that the majority of the plants were growing in the north-east corner of the site and NMR established a 0.8ha Grand Spider Orchid preservation area at the site. One threatened ecological community - a naturally occurring combination of plant species - was also identified at the site of Warnbro Station. A new station design was created to preserve nearly one hectare of the best quality of this vegetation.

A Fauna Management Plan was prepared prior to construction to minimise impacts on native fauna. Two fauna underpasses were constructed in Leda Nature reserve to allow access between areas of the reserve on either side of the railway. Also, temporary fencing of the entire rail alignment prior to clearing was raised to prevent fauna kills. Permanent fauna proof fencing with mesh buried to a depth of 300mm now surrounds the railway.

Heritage

A number of Aboriginal site investigations were conducted along the route of the Mandurah Line alignment. The investigations included extensive consultation with relevant Aboriginal groups from Perth to Mandurah. As a result, NMR decorated a station with Aboriginal artworks, included information on the Aboriginal association and usage of the Swan-Canning area along the Narrows Bridge and provided groups with access to felled timber.

Heritage buildings in the city which were retained are the old Bairds building, the Globe Hotel, the Wellington Building and the distinctive façade of Mitchell’s Building on William Street. There was consultation with the appropriate authorities, in particular with the Western Australian Heritage Commission, in order to minimise adverse impacts to heritage places.

Landscaping and revegetation

Landscaping along the rail line, excluding stations, required 315kg of seed and 427,000 individual seedlings. Seed collectors collected seed from the rail alignment from up to 100 different local species. This seed was used in the landscaping works. Rehabilitation works, including topsoil replacement, mulch respread, weed spraying, seeding and tube stock planting have all been completed.

Noise and Vibration

NMR employed specialist acoustical consultants to conduct studies and predict the noise impacts for each section of proposed railway. Strategies that were used to lower the noise levels included the construction of noise walls and earthen bunds, use of rubber ballast matting and jointless tracks for the train to run on. The new state-of-the-art railcars purchased produce significantly less noise than the old fleet. This is because the traction motors are mounted above the suspension system for the train, which reduces the unsprung mass of the train, resulting in less noise generated at the wheel-rail interface.

Studies of the vibration levels of the current electric passenger rail service have shown that the magnitude of vibration is significantly less than the level which would cause any structural damage to buildings. Where it was anticipated that significant vibration levels will be produced, NMR considered options to reduce them. These included the use of rubber ballast matting, resilient rail fasteners or isolating the track through slab track design of sensitive sections of the alignment.

Public Consultation

Extensive consultation was conducted through more than 100 meetings with 25 interest groups. NMR prepared a Stakeholder Consultation Strategy with the aim of ensuring that consultation continues with all relevant stakeholders and that outcomes are incorporated into the management of the project.

An Environmental Community Consultative Committee was established in February 2002 with representatives from local environmental groups. The committee was set up to increase community awareness about the project and address any environmental concerns the community might have had. It was a very successful committee which resulted in a number of environmental initiatives being adopted by the project, such as preservation of threatened ecological community vegetation at Warnbro Station, topsoil and mulch stockpile management and realignment of railway route to minimise impact to Pickle Swamp

Public Risk and Safety

A risk assessment was carried out for the Mandurah Line to determine the level of risk of collisions between trains and vehicles. This was minimised by the construction of concrete crash barriers on each side of the railway line. Also, all road crossings over the line are by bridges – either road over rail or rail over road. Areas within the Rockingham Lakes Regional Park were used as artillery ranges in World War II and may have been contaminated with unexploded artillery shells. 100 per cent clearance was required before earthworks commenced and no live ammunition was found.

Soil and Groundwater Contamination

Detailed geotechnical and hydrological investigations were carried out along the route of the Mandurah Line to determine areas with the potential for contamination, particularly in the CBD area. After extensive testing, areas of Acid Sulfate Soils (ASS) were identified at the Cockburn Central Station site, Secret Harbour and the Perth CBD. Acid Sulfate Soils are soils which have the potential to become acidic when exposed to air. This can result in a variety of environmental complications such as acidification of soil and water and the release of heavy metals into the environment. The disturbed soil was treated to prevent the generation of acid conditions and disposed of to an appropriate location. NMR has also undertaken a water quality monitoring programme. The programme takes samples from groundwater bores and wetlands and the results are analysed to ensure that the operation of the railway does not adversely impact the groundwater and nearby wetlands.

Sustainability

Sustainability is defined as meeting the needs of current and future generations through integration of environmental protection, social advancement and economic prosperity. In terms of the NMR project, sustainability means maximising the opportunity to increase residential, employment, retail, community and entertainment activity around key transport nodes and in major centres. It also involves achieving a more sustainable balance between car use and other transport options through the promotion and provision of efficient and effective public transport and non-motorised personal transport alternatives.
A 2004 "triple bottom line" report found that the NMR project achieves its sustainability goals in terms of its economic benefit-cost ratio, and that substantial environmental and other non-economic benefits will flow from the project.

Visual Amenity

A Visual Impact Assessment was completed for the entire route of the Mandurah Line. From this, positive external and internal views in the CBD were created by the sinking of the train line and removal of the existing ramp at the western freeway end of William Street. To overcome visual intrusion from masts along the Narrows Bridge to Mount Henry Bridge, slimmer blue coloured steel masts were used in preference to concrete masts. Areas that required revegetation and rehabilitation were planted with native species to enhance the character of the local environment. 

Wetlands

The route for the Mandurah Line takes it through the proximity of several wetland zones. Those closest to the alignment include the Leda Wetlands, Pickle Swamp, Anstey Swamp, Paganoni Wetland and Black Swan Lake. The rail alignment was routed to avoid impacting these wetlands as far as possible. Management practices to control run off and maintain natural flow regimes were implemented during construction. Where necessary, silt traps were constructed and drainage patterns were maintained through the use of vegetated swales to promote infiltration at source.

Environmental Outcomes

The completed Mandurah Line will deliver enhanced benefits to the environment for decades to come by:

• Providing a greener transport mode for commuters to the southern suburbs.
• Decreasing emissions associated with traffic congestion through greater commuter use of public transport. 
• Decreasing fuel consumption and emissions through the use of electric trains. 
• Providing environmentally sustainable transport for future generations. 
• Improved visual amenity from an underground railway through the city. 
• Reduced congestion and traffic impacts from constructing an underground railway that makes more efficient use of the road network within the city. 
• Long-term benefits from tunnel boring techniques which are more environmentally sound than large tracts of cut-and-cover tunnelling work within the city. 
• Minimised site impacts through reducing the base size area of the Perth Underground and Esplanade stations. 
• Lowered power consumption at both urban stations through the optimisation of space utilisation. 
• Lowered power consumption at Esplanade Station through design that makes extensive use of natural light and ventilation. 
• Extensive use of reflective surfaces and finishes to enhance lighting and minimise energy consumption. 
• An innovative system that converts kinetic energy to electricity during the braking process and returns the electricity back into the power system. An estimated 20-30 per cent of the energy required to run the trains will be returned via this "regenerative braking" technology.

Environmental plans relating to the NMR project are available on request by emailing enquire@pta.wa.gov.au