ater nfrastructure cience & ngineering

Why are surface water options ignored in the Pilbara?

20 February 2015

The Commonwealth government has targeted development of water infrastructure as part of the White Papers on Developing Northern Australia and Agricultural Competitiveness.

In much of the eastern states of Australia this has included a focus on constructing dams. In Western Australia a Pilbara and/or Kimberley irrigated water pipeline system has been identified for feasibility studies.
Due to the geological formations of Western Australia groundwater options typically provide greater feasibility and sustainability.

When we look at the national rainfall and evaporation patterns it is easy to see why the Pilbara and Ashburton coast is used for salt mining (from evaporated seawater). Net evaporation is typically 3,000mm above an average rainfall of approximately 300mm.

As a result surface water dams perform poorly as storage basins in the coastal Pilbara and the evaporation serves to concentrate poor water quality. Natural heating of the reservoir water body causes the water to turn over which increases sediment and turbidity (natural organic matter: NOM) in the water body.

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And dams can often have significant impact on social and cultural values. But that’s for another discussion …