Major roadworks on the Great Northern Highway, near Walebing, are being aided by the use of water acquired from an ancient palaeochannel identified by the Department of Agriculture and Food.
The Capitela borefield was detected as part of the West Midlands Mapping and Water Management project that focused on salinity risk assessment and the potential for new agricultural water supplies in the Gillingara valley.
A production bore drilled to assess the palaeochannel aquifer, located on the Gillingarra-Glentromie Road, is being used by contractors to Main Roads Western Australia, Brierty Limited, for pavement construction activities, such as dust suppression and compaction.
Brierty project manager David Cartwright said the water sourced from the Capitela borefield was a benefit to the $45 million project to upgrade a 21 kilometre stretch of the highway.
“Different elements of the construction process require water of varying quality, with the demand for high quality water less than that for poor quality water,” Mr Cartwright said.
“Brierty sourced the water required for this project from a number of different sources, due to the scarcity of water in Western Australia, including saline water from three soakwells and potable water from the Moora townsite scheme water supply.
“The bore proved most useful, providing a total of 60 Megalitres of fresh (brackish) ground water, sourced at a rate of 6.01 litres per second, for pavement construction.
“Using the Gillingara-Glentromie Road bore resulted in reduced demand from the Moora town scheme supplies.”
The Capitela palaeochannel was identified as part of a collaboration between the departments of Agriculture and Food, Water, and Regional Development and the CSIRO, with support from the Gillingarra-West Koojan Land Conservation District Committee and Royalties for Regions funds.
Department senior hydrologist Russell Speed said scientists were not expecting to find such a large water source.
“In the course of analysing the results of an airborne electromagnetic survey (AEM) we were surprised to find a 200 metre deep, 15 kilometre long palaeochannel, stretching from Gillingarra to New Norcia,” Mr Speed said.
“The AEM survey covered 35,000 hectares and subsequent drilling has found good volumes of reasonable quality water that could readily be used, for example, to irrigate pasture species for fodder production.”
While the focus of the department’s work is to identify sustainable water sources for agricultural development, it does work with other non-agricultural collaborators.
For example, the department’s Pilbara Hinterland Agricultural Development project is working closely with miners in the north to explore the use of surplus mine water to cultivate crops, such as fodder for stock feed.
This project has been made possible by Royalties for Regions. More information on this and other water department water projects is available on the website.
Media contacts: Jodie Thomson/Lisa Bertram, media liaison +61 (0)8 9368 3937