A 2.4 million litre Ausdrain EnviroModule2 rainwater harvesting tank was installed at The Scotch College, Melbourne in October 2008. The tank consisted of 23,265 Ausdrain extra-duty modules.
Extensive earthworks were carried out by All Waste Solutions. To install the rainwater harvesting tank, fill under the schools soccer playing field had to be excavated and removed. Due to the presence of a high water table, the depth of the rainwater harvesting tank was restricted to 1350mm (3 modules deep) with a further 900mm of cover to create even load distribution for vehicular traffic.
The rainwater harvesting tank was installed by H2O Innovations, an approved Ausdrain installer. A strong and durable 1mm re-enforced polypropylene liner was used to surround the rainwater harvesting tank. Due to the size of the rainwater harvesting tank, the liner was installed in sections and welded on site to guarantee a watertight situation. A thick layer of geotextile protection fabric was used between the liner and modules and to surround the base, sides and top of the rainwater harvesting tank prior to backfilling. Stabilised sand was used to backfill the sides of the rainwater harvesting tank with a 200mm layer over its surface further enhancing its structural capabilities.
The project also required underground tunneling and the laying of pipe work to connect the downpipes from the school buildings to the tank. A state of the art pumping system and extensive irrigation works completed this project thereby providing the college with an ample supply of water for the irrigation of its sports playing fields.