Stormwater harvesting project

With south-east Queensland schools reeling from recent double-digit water price hikes, many school business managers are looking for a way to help ‘futureproof’ their facilities against similar water price rises in subsequent years.

When considering the design of a stormwater harvesting system, the All Saints Anglican School, located in the Gold Coast suburb of Merrimac, engaged VDM Consulting engineers to ensure that the project provided a ‘triple bottom line’ result. The solution had to reduce the cost of potable water, improve environmental conditions and provide ongoing educational value for students.

At the time of developing the project, the federal government’s Water for the Future program had made $200 million available to support stormwater-harvesting projects that reduced demand on potable water supplies. Individual grants of up to $20 million were available for 50% of eligible capital and professional consulting expenditure associated with stormwater harvesting projects.

The All Saints Anglican School stormwater harvesting project consists of an artificial wetland to harvest stormwater run-off for irrigation of a sports field, an educational area for students and improved local ecological values via a habitat for migrating birds. The wetland was designed using the latest hydraulic and ecological modelling methods, taking into account the surrounding topographic and aesthetic features together with associated civil engineering and site supervision services.

VDM Consulting completed the Water for the Future documentation in conjunction with the client who was subsequently awarded a generous grant of approximately $500,000 from the federal government. The balance of the school’s capital expenditure will achieve a payback period of approximately four years, based on AS 3598 assessment methodology, and reduce usage of potable water by approximately 120 ML per annum.

Given the fact that utilities costs for schools including potable water are typically approaching 10% of annual operating costs, the All Saints Anglican School stormwater harvesting project provides a model for the emerging ‘retrogreening’ market for upgrading of school utilities infrastructure. By undertaking these projects in conjunction with available government grants, the project payback period can be significantly reduced, as demonstrated by this project.