Quantifying surface water - groundwater exchange using thermal & chemical measurements

This project will develop field equipment and a proven scientific methodology that will quantify surface water - groundwater transfer to aquifers beneath river beds and therefore contribute to the mapping of the many and complex connections and interactions between groundwater and the surface water - dams, lakes, rivers, wetlands.

Improved scientific understanding of the connectivity between surface water and groundwater will enable the irrigation industry to store water and thus avoid unnecessary wastage to evaporation in areas adjacent to a river. Understanding and mapping these "connected waters" are crucial to Australia’s social, economic and environmental future.

Professor Ian Acworth from the Water Research Laboratory at The University of New South Wales (UNSW) leads the team undertaking this important project which is part of the UNSW Connected Waters Initiative.

Connected Waters website.

Aims

This project seek to design, develop and test an integrated measuring tool that can be installed and recovered from the bed of streams and rivers. It is envisaged that the tool will be 1.5 m long and 80 mm diameter with removable sensing and logging elements. The tool will comprise temperature and water level loggers and newly developed probes to monitor fluid electrical conductivity, the concentration of chloride in the water and oxygen levels. It is envisaged that multiple tools will be deployed at selected sites and recovered after 2 to 3 months for download and analysis. Data from the new sondes will provide real field data and allow a much improved conceptual model of hyporheic zone beneath and adjacent to surface water bodies that are connected to aquifers. This, in turn, will better inform management and allocation decisions.

The initial approach has been successfully tested as part of the Cotton Catchment Communities CRC program of works in Maules Creek. We are now confident that these methods can be substantially further developed and this project would undertake that work.

Outcomes

As a result of this project, there will be much improved knowledge and understanding of a process that can, in turn, inform policy development and water allocation decisions. The new knowledge will allow development of advisory and/or project management services based upon deployment and interpretation of the sondes.

In addition field data acquired by the sondes could provide much needed independent confirmation of various other modelling studies.

Background

Australia is often said to be the driest continent on Earth - but that’s only because of its low rainfall. In fact, while the surface of the land is dry, we have massive groundwater reserves.

Groundwater makes it possible to grow much of our irrigated crops and pastures. Governments are looking increasingly to these aquifers to provide drinking water for our growing towns and cities. Groundwater use has almost doubled nationally in the past two decades, (it now makes up more than one-fifth of all the water we harvest) yet we know far too little about how to manage it sustainably

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