Link Gabion and Rock Mattress for Queensland’s Wyaralong Dam Project

Project snapshot

The Wyaralong Dam is located approximately 14 km northwest of Beaudesert and is part of the Queensland Governments' water sustainability plan for the growing South East Queensland population. It supplies approximately 21,000 ML per annum to the rapidly expanding region and was completed in 2010.

Global Synthetics was involved in the early stages of this project, supplying a series of gabions and mattresses to manage complex creek crossings, culverts and retaining structures constructed to manage a 10km road realignment alongside the dam location.

The challenges

One of the many challenges faced was that the existing Beaudesert Boonah Road would need to be realigned to accommodate the new dam location.

A new section of road approximately 10.6km in length needed to be constructed and tenders were called with the successful contractor beginning works in mid-2009.

Throughout the 10.6 km realignment, there were several creek crossings, culvert structures and retaining structures that were required, and gabions and rock mattresses were selected as retaining structures, culvert outfalls/inlets and scour protection.

Strict specifications were set out under Queensland Water Infrastructure (QWI) and the Queensland Department of Main Roads documentation.

Our solution

Global Synthetics was awarded the tender to supply the gabions and rock mattresses, meeting all the requirements of the specification. Particular requirements were placed on the quality of the wire coating with a Zinc / Aluminium / Mischmetal product specified.

Global Synthetics was able to supply such a product with the licensed Galfan® coating technology used. The originating technology of the Galfan process supports the view that the life of coated wire can exceed that of traditional heavily zinc-coated products by a factor of 3 to 4 times.

For this project, the contractor employed the services of two specialist gabion/mattress installers to undertake the installation with over 9600m2 of mattresses and 4300m3 of gabions installed on the project.

Global Synthetics was also successful in supplying the geotextile required for underneath the gabions and mattresses (along with other project applications) with over 120,000m2 supplied. Some 7 km of road edge drainage pipe has also been supplied to the contractors.

The project manager reported that they were very happy with the way Global Synthetics serviced their tight delivery schedules for construction, and our ability to demonstrate product compliance to the specifications.