St Kevin’s College

When St Kevin’s College required a sustainable rain harvesting and storage solution to keep the grounds looking green, they called on our underground tank expertise.

Brief

Great Spaces specialise in the installation of sustainable water-saving solutions as part of our full-service landscape design and construction services – from megalitre underground council tanks to 100,000 litre tanks for schools, to rainwater tanks under a residential deck.

A standard football pitch requires a minimum of 150,000 litres per week to keep a pitch in a healthy and safe condition. With rising water costs, St Kevin’s College required a sustainable rain harvesting and storage solution to maintain its playing fields and landscaped grounds. Great Spaces landscape designer and project manager Peter O’Neill was engaged to oversee the project with his specialist underground tank sister company – Sub Terra managing the tank installation.

Design

At the heart of the design was a 2 million litre Eco3 modular tank from civil engineering supplier Rocla. The tank itself was comprised of 8600 double recycled plastic modules. With a footprint of 2250 square metres, the rainwater tank needed to be installed below the main oval and playing fields at St Kevin’s Toorak campus. Care and attention to would need to be taken to ensure the reinstatement of a top-quality playing surface, with the necessary bounce, traction, and safety characteristics required to host major sports.

Construction

Large scale groundworks were required to prepare a pit for the tank. A 600mm layer of cover material was stripped off the surface and stored in a stockpile to be reused under the new pitch. At 1.8 metres the formation level of the assembled tank required the excavation of over 6000 cubic metres of soil to be removed from the site.

Base materials were laid and levelled, followed by installing a geo fabric liner and the Eco3 modules. Backfilling included a layer of crushed rock layer followed by clay from the stockpile. Pumps, plant equipment, and plumbing was installed to manage rainwater collection from campus buildings. At the same time, a connection to the adjacent Gardiners Creek provides another water source. And the grounds irrigation systems were reinstated.

Landscaping involved the accurate establishment of levels (a slope of no more than 1 in 200 along the line of play and no more than 1 in 100 across the line of play) to accommodate rainwater run-off and ensure a surface free of undulations. High-quality sports-grade natural turf was laid to complete the groundwork. The result is a sustainable solution to improve facilities, lower maintenance costs, and provide green playing fields for the next generation of St Kevin’s sportsmen and women. The entire project took three months from start to finish.

To see a time-lapse film of the installation of this underground water harvesting and storage system, click here