Hanson’s A-Jacks an environmental saviour
An innovative product by Hanson is saving Queensland’s Coomera River from erosion – and in doing so has earned Hanson an environmental commendation award.
Eighteen months ago, the foreshore of the Coomera River at Charles Holm Park on the Gold Coast was eroding at a rate of one metre per year from the wash of commercial vessels. In May 2004, Hanson’s environmental innovation, A-Jacks, was trialled as a means of preventing this erosion.
A-Jacks are high stability concrete units designed to interlock into a flexible and permeable matrix. The stability of A-Jacks is due to its design. When laid in a uniform pattern, each A-Jack block interlocks with six adjacent units, creating a highly stable platform.
For the trial, A-Jack blocks were laid 100mm below the low tide mark along the river’s embankment and as an upper wall 300mm above the lower section. The expectation was that the A-Jacks system would break down the waves caused by commercial vessels into a gentle ripple, dramatically reducing the scouring of the riverbank.
Today, erosion of this section of river has ceased. Just as importantly, the mangroves, previously stressed due to the receding shoreline, are again thriving, according to Hanson. The A-Jacks blocks provide a stable and protective structure for the mangrove seeds to grow through. As the rehabilitation is completed, the A-Jack blocks remain stable and become completely covered in mangrove roots.
As a result of its use on the Coomera River banks, the A-Jacks system received special commendation in this year’s CMAA Public Domain Awards for Sustainable Design. The commendation recognised A-Jacks’ unique ability to both control erosion and facilitate vegetation rejuvenation, as well as its ease of installation and the absence of on-going maintenance requirements.
18-Oct-2005