Jacka Street Reserve

When the City of Boroondara required a landscaping solution to prevent flooding and harvest rainwater. They called on our skills to install one of the biggest underground tanks in Australia.


The Great Spaces team has extensive experience in sustainable water-saving solutions, from large-scale underground tanks to domestic rain capture and irrigation systems. When the City of Boroondara required a detention and landscaping solution to both prevent flooding and harvest rainwater, Great Spaces Peter O’Neill was engaged to oversee the project with his specialist underground tank spin-off – Sub Terra managing the install.


Unlike rainwater tanks, stormwater detention tanks are based on a modular system with special valves to release water over time slowly. The detained water helps prevent flooding on local roads, creeks, parks, and surrounding properties during heavy downpours. The submerged reservoir located at Jacka Reserve was required to hold enough water to fill two Olympic-sized swimming pools or 4.6 million litres.

In this instance a modular tank design was chosen to allow the water reservoir to be configured in an irregular shape to adjust to the terrain and work around existing trees on the site. The tank not only reduces local flood risk, it provides a valuable water source to feed the reserves bush vegetation, sports grounds, and nearby parkland.


With this being one of the largest underground tanks in Australia, the project required excavation, engineering, and drainage works on an industrial scale. The pit alone covered the area of a regular football field and required the removal of over 15,000 cubic metres of soil.

The tank itself was made of 43,000 recycled plastic modules, which had to be assembled, linked, and installed by hand. Upon completion of the tank, works involved backfilling and landscaping to restore the parkland above to its original condition, including reintroducing native flora, grasses, paths, and natural features. Linear depressions (swales) were also incorporated into the landscape design to control and channel rainwater run-off into the detention system.

Then completed works provide peace of mind for nearby residents during heavy rain and more green space for the Boroondara community to enjoy year-round. The entire project took 6 months to complete.