Garramilla Boulevard – A Landmark in Climate Resilient Green Infrastructure Case Study
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About the Project
Darwin’s iconic Garramilla Boulevard recognizes the Aboriginal heritage of the CBD honouring the local Larrakia people. Garramilla is the Larrakia name for “white stone”, which is in reference to the white rock found in the Darwin area. Garramilla Boulevard, formerly known as Barneson Link Road, is one of Darwin’s most significant urban infrastructure projects in recent years.
Planned as the primary gateway into the city, this fully tree-lined boulevard connects the CBD to surrounding suburbs, offering a cooler, more
comfortable passage for pedestrians and cyclists in an environment often marked by extreme heat and severe weather events.
With temperatures reaching 38°C in wet season and long periods of intense humidity, Darwin’s urban planning faces unique challenges. Accordingly, climate resilience, pedestrian accessibility, and the integration of large shade trees were essential elements in the vision for Garramilla Boulevard.
A key feature of the road are the rows of trees planted in linear stratavault tree pits, providing suitable soil volumes to ensure maximum canopy
coverage is achieved to create a landscape boulevard that was always envisaged by the city planners.
Tony Cox explained how the Stratavault system became integral to the project success:
• Deep Root Establishment: Stratavault allows trees to develop deeper, stronger roots, making them more resistant to extreme weather events like cyclones.
• Road Protection: Engineers were concerned about road pavement stability and water infiltration affecting underground infrastructure. Back-of-kerb root barriers were incorporated to mitigate these risks, ensuring trees could grow without damaging critical transport corridors.
• Water Management: Darwin experiences wet and dry seasons, so water penetration into road pavement was a major concern. The Stratavault system helped control water drainage, ensuring moisture reached tree roots while protecting surrounding surfaces from water logging.
• Long-Term Soil Quality: Traditional tree planting in compacted urban soils often leads to stunted growth and premature tree failure. By using Stratavault, consistent soil volume and quality were maintained, setting up trees for generational healthy canopy coverage.
Faster Than Expected Canopy Cover
Selected tree species were chosen for their cyclone resilience and ability to offer impressive shade – Albizia saman (South-American Rain Tree), Syzygium armstrongii (Bush Apple), Allosyncarpia ternata (Anbinik) and Maranthes corymbosa (White Cloud Tree).
After less than four years, tree growth rates have exceeded expectations, with results attributed to
1. High soil volumes provided by the Stratavault soil cells ensuring strong, deep root development.
2. Strategic irrigation and maintenance that focuses on shifting the perception of trees from “cost burdens” to valuable urban assets that appreciate over time.
Data and Performance Metrics
Cloustons and its project partners are now assessing key metrics, including:
• Canopy coverage comparisons (before-and-
after data using aerial and satellite imagery).
• Carbon sequestration rates, with studies in
collaboration with CSIRO.
• Surface temperature reductions, demonstrating
tangible cooling effects of increased vegetation.
This evidence will not only validate the project’s
success but will be used to support future urban
greening initiatives across Darwin and other high-
heat regions.
Impact on Future Projects
Garramilla Boulevard serves as a blueprint for climate-
resilient urban infrastructure, and the lessons learned
are informing other greening initiatives in the Northern
Territory, including:
• City of Darwin’s Smith Street project,
incorporating Stratavault and large soil volumes
despite constraints of existing services.
• Cavenagh Street redevelopment, which highlights
how retrofitting tree solutions into existing urban
landscapes can yield positive results.
