Gold Coast Light Rail Stage 2 – GRT Erosion Control and Dust Suppression

Background

As part of the Queensland Government, Australian Government, and the City of Gold Coast’s plan to support the Gold Coast 2018 Commonwealth Games, it was determined that an extension of the Gold Coast Light Rail would be required. This stage 2 project would not only also be critical in meeting the increasing demand for public transport from the community, it would provide seamless connections for visitors and locals between Queensland’s capital, Brisbane and Australia’s fastest growing city, Gold Coast. 

This stage 2 extension would introduce two crucial erosion and dust suppression projects that would later come to provide the foundations for the 7.3km dual track light rail. Due to the light rail being designed and constructed within suburban areas and along main roads, meticulous planning were required for the two projects to not only ensure regulations and standard were met, but to also ensure potential health, safety, and environmental risks were realized, managed, and mitigated.

Challenges

With the stage 2 extension project designed between roads and within suburban areas, earthmoving plant and heavy vehicles were introduced to the narrow corridor in which the rail track would later be laid down. Furthermore, an increase number of vehicles (moderate and heavy) working on site would introduce severe dust problems that would affect workers and vehicles alike. These dust problems would also be generated in much greater volumes due to the constant traffic travelling on the major roads next to where the light rail would be constructed. 

In addition, the natural constraints of the stage 2 project would deliver many erosion prone areas (up to 600,000m2) to the design and construction of the light rail. An erosion issue was present at a major part of the light rail extension where the light rail would travel within a slim linear corridor located between smith street motorway and a residential area. Due to stage 2’s project having similar conditions to the stage 1 project in terms of erosion environments, it was determined that an increase of construction within the slim linear corridor would deteriorate the structural integrity of the soil and rocks within; which would inherently bring forth erosion. 

Furthermore, as the $420 million light rail stage 2 project was completed in around 16 months, there were several storm seasons within the design and construction period where high rainfall was present during construction. This meant that high winds and storm events were likely to cause land degradation and potentially transport unwanted material on to the construction of the light rail. This meant that several construction sites for the light rail would become unusable during and/or after a rain event. If construction were to be paused for a few days on this multi-million projects due to these conditions and complications, losses would quickly mount up. 

Solutions

The GRT team provided an area assessment on the projected light rail route to determine the most suitable product/s considering both the environmental and economic impact this product may potentially develop after application. While normal construction by various organisations would consider controlling the dust and sediment runoff, GRT determined that the best methodology of controlling erosion was to not have it occur in the first place. So instead of developing a strategy of having sediment fences and ponds, GRT would stop erosion at the source. 

This strategic decision made GRT: Enviro-Binder the recommended product for the erosion control of the Gold Coast stage 2 light rail project as it:

• Was a uniquely developed product that followed the ideal of “STOP EROSION AT THE SOURCE – DON’T CATCH SEDIMENT”
• Provided exceptional erosion control immediately after application.
• Met the strict environmental criterial imposed by the Queensland Government and partner company, CPB Contractors.
• Required minimal maintenance unlike conventional methods.

GRT: Enviro-Binder is a film-forming polymer emulsion sprayed on or worked into the surface of cuttings and embankment to provide a waterproof, durable, surface that prevents erosion. 

GRT: Soil-Loc, one of GRT’s most advanced polymer surface stabilizers, was one of the recommended products for the light rail as it:

• Provides protection on the top layer of the soil against unwanted or contaminated materials
• Ensures that land degradation and removal of topsoil from high winds and storm events will occur.

Benefits

The GRT: Enviro-Binder treated light rail and associated construction sites delivered high performing results that were expected from the product:

• Provides cut and embankment batter protection.
• Eliminated the need for sediment fences onsite.
• Minimal soil preparation for product application.
• Waterproof product; not affected by high rainfall or storm seasons.
• Cost effective results.

The GRT: Soil-Loc treated light rail and associated construction sites also delivered low cost, effective, results that were expected from the product:

• Cost effective treatment for exposed, dusty surfaces.
• Allowed the site to be shut down over the dry Christmas period with no water trucks required to manage the site’s open areas susceptible for dust.
• Water savings over this period of over 200,000L when compared to daily watering requirements.
• ZERO dust related complaints received over the shut down period.