West Gate Tunnel Project

The project developed an Energy Management Plan aiming to minimise energy consumption and GHG emissions caused. The emissions modelling results show a total 46% GHG emissions reduction (20.3% reduction in construction phase and 52% reduction in operation); from a base case of 1,091,844 tCO2e to an estimated actual case of 591,990 tCO2e for the project Design. The initiatives implemented by the project include:  

1. Design changes that contribute to a 17% reduction of energy use (compared to base case) during construction: 

• Extend the overall length of the tunnel and avoiding a high voltage line relocation and a rail crossing  

• Avoiding a new Geelong road bridge by improving the interchange with the M80 connection  

• Improving roadway design to eliminate the need of Wurundjeri Way Bridge  

• Reducing the size of cross passages within the tunnel by using innovative tunnel design and hosting equipment in the maintenance tunnel  

• Avoiding construction of a separated, elevated shared user path along Footscray road by use of an integrated Veloway  

• Eliminating use of bypass pumping during diversion of the North Yarra Main Sewer by utilising an innovative mechanical, telescopic flume (Extra evidence from Flume innovation)  

• Reducing elevated roadways within city connections  

1. Use of single row of LED lights compared to a double row of CFL lights that contributes to a 32% reduction of energy use related to tunnel lighting during operation 

1. Use of separate low-pressure variable speed fans that contributes to a 70% reduction of GHG emissions related to tunnel ventilation during operation 

1. Use of LED lighting that contributes to a 19% reduction of energy use related to road lighting during operation 

The project achieved a water reduction percentage of 58.3% from a Base case of 12,187,793 kL and to an estimated actual case for Design of 5,080,953 kL. The initiatives implemented by the project include:  

1. Groundwater injection (construction): The installation of ‘grout curtains’ reduces the quantity of water that needs to be re-injected into the ground to maintain stability of the water table. 

1. Freeway control Centre (operation): Use of more efficient toilets, urinals, taps, washing machine and dishwater.  

1. Road maintenance (operation): Design efficiencies achieved during construction in the form of reduced asphalt flow through into the operational stage in the form of reduced asphalt replacement requirements. 

The project identified the councils that were going to be impacted by WGTP that include:  

• Hobsons Bay City Council 

• Maribyrnong City Council  

• City of Melbourne 

• Wyndham City Council 

• Brimbank City Council 

Then, WGTP identified four priority issues to address: 

1. Access to active transport facilities: WGTP will deliver over 14 km of new and upgraded walking and cycling paths, making travel easier and safer. This provides benefits that include connecting disjoined trails, removing road crossings, and elevating bike paths. Safe and sustainable commuting corridors encourage active transport and improve the connectedness in the West of Melbourne. 

1. Local businesses: WGTP worked to provide opportunities for “true” local businesses on the project, which include encouraging small/medium businesses to register as project suppliers by distributing call for expressions of interest through councils and trader/industry groups, co-hosting events with councils, maintaining live contracts to provide opportunity and transparency and use social and mainstream media channels available to publicise local suppliers. Also, the project is working towards targets to source from social enterprises and Aboriginal businesses. 

1. Diversity and Social Inclusion: In addition to the Social Procurement Strategy, the WGTP Workforce Development Plan includes strategies and activities to ensure 20% of the workforce participates in nationally recognised accredited training, meet or exceed the Aboriginal employment target of 2.5% of total labour hours, and achieve a 4% of Aboriginal employment. It also targets improvements in workforce diversity through gender diversity targets.  

1. Community Education: WGTP commenced the West Gate Kids program in parallel with construction progress from 2018. The program is a school engagement program designed to complement the current school curriculum with age appropriate activities associated with WGTP. Part of the project is run through SciencePlay Kids, led by award winning scientist Dr Lorien Parker, who delivers sessions of ‘Engineering our City’, that targets Science, Technology, Engineering, Arts and Mathematics (STEAM) alongside careers education. 

This is a cycling path that connects Melbourne Docklands to Footscray via Footscray Road. 

The design was generated through innovation workshops within the tendering phase of the project, where a variety of process and design options were assessed. The design itself integrated the bike path connection into the elevated road design, resulting in an integrated, ‘hanging‘ Veloway that is entirely supported by the roadway. This design innovation maintained the bike path connection whilst maintaining the existing shared user path and removing material and construction activities associated with a self-supported structure. The level of integration of the segregated Veloway within the project design across such a significant length of road are the attributes that have not been delivered by any previous projects in Australia. 

The key differentiating feature of the tunnel design is the use of the area under the deck as a service tunnel to house ME&I equipment.  By not backfilling this area, as would typically occur, there are safety, economic, social, and environmental benefits:  

• Reduced need for workers to be near moving vehicles 

• Reduced need to close the tunnel or lanes within it when conducting maintenance 

• Reduced materials and truck movements by having reduced cross passage sizes and not having to backfill the tunnel 

This innovative tunnel design has been acknowledged as an Australian first by the Australian Tunnelling Society.  

WGTP has adopted a dedicated low-pressure ventilation system for normal operations in addition to a separate high-pressure ventilation system for smoke spill (emergency use only). 

This innovative tunnel ventilation system has been acknowledged as an Australian first by the Australian Tunnelling Society 

The mechanised telescopic flume innovation came through the functionality of constructing permanent diversion works whilst providing live flow diversion. This provided a direct alternative to the use of large-scale pumps needed for bypass pumping of the sewer which was the proposed standard process during tender.  

The process provided direct improvement through efficiency compared to the tender proposal of bypass pumping. Sustainability benefits came in the form of:  

• Resource savings through construction efficiency including direct energy and emission reductions through plant and equipment diesel consumption of 290 kL, as well as material use reduction of 2250m of 900mm temporary piping  

• Project cost savings of more than $4 million