Green light for sustainable water solutions.

The future of Australia’s water resources depends on smart science – especially to ensure the longevity of sustainable agriculture – and Professor Adrian Werner considers this foremost as he investigates improved groundwater system management in northern Queensland.

His focus is the Lower Burdekin Delta system (about 90km southeast of Townsville), Australia’s largest artificial recharge scheme that is maintaining underground water reserves to support continued intensive agriculture in one of Australia’s most productive sugarcane-growing areas.

“A significant part of this research will be to assess future climate and sea-level conditions on groundwater, especially the intrusion of saline water into aquifers and groundwater,” says Professor Werner, a member of the National Centre for Groundwater Research and Training, based at Flinders University. “Aside from the relevance to local landholders, the outcomes will have great significance for other areas. For example, the successful deployment of artificial recharge to maintain the groundwater system holds important lessons for other water-limited parts of the country. This project will deploy instrumentation in the Lower Burdekin Delta using irrigated farms as outdoor laboratories.”

The research to help sustain intensive agriculture through droughts and floods in the Lower Burdekin Delta is supported by $897,000 in ARC Linkage funding, working with industry partner Lower Burdekin Water and a team of experts in groundwater, soil and hydrochemistry from three other research institutions. Professor Werner’s role leading this group underlines Flinders’ reputation as leaders in field-based investigations, laboratory-based experiments and computer modelling of groundwater.

The Lower Burdekin Delta is one of Australia’s largest floodplain and delta systems, covering 1260 km² within the catchment of the Great Barrier Reef World Heritage area – a region that produces one-quarter of Australia’s total sugar production and represents the largest irrigation area in north-eastern Australia.

The tropical climate presents farmers with significant challenges to ensure year-round water supply for irrigation, with very dry winters and then vast amounts of rainfall in concentrated downpours. With these farms located close to the coast, management of the system needs to ensure that irrigators avoid salty water that has the potential to reduce crop productivity and soil fertility. Overcoming this challenge requires careful operation of the artificial recharge scheme, which includes the injection of river water into pits to enable continued groundwater pumping. Professor Werner believes that increased efficiencies in water use can be achieved from the field measurements and experiments and computer models created through this project.

“Through collaboration with Lower Burdekin Water, we are hoping science can deliver improved water planning and management tools for the region, including new benchmarks in adaptive groundwater management strategies for agricultural areas in Australia,” he says.

To build specific knowledge of this localised system, Professor Werner needs to know how, when and where farmers are pumping groundwater and applying it to the land. “There are many lessons to be learned from the existing agricultural practices and water management approaches of the Lower Burdekin Delta because they don’t have major water quality issues and they maintain certain efficiencies. If we apply better science to what they are already doing, it can only improve the way they are currently operating, and then we can pass on our accumulated knowledge to benefit other irrigation areas.”

There are many shifting natural forces for the scientists to consider with this analysis, including rising sea levels, climate change and changing flows in the Burdekin River. To help them understand the delta’s complexity, they will use a new state-of-the-art seawater intrusion model that will adopt a 3D representation of the coastal aquifer.

“Think of an aquifer as being like a bank account,” explains Professor Werner. “If you make too many withdrawals, the groundwater drops, and if you put too much water into the aquifer, the mineral salt level leaches higher into the soil with the rising water. If contaminated water accumulates into the aquifer or discharges to sensitive ecosystems, it can lead to negative outcomes.”

“The big picture is about far more than just efficient irrigation. It’s about the ongoing health of a vital water system. It will interlock with other research that can provide a more cohesive environmental solution for intensive agriculture and irrigation areas, which can be applied to areas across Australia.”

Professor Werner emphasises that this project must provide translational research from a multidisciplinary and consultative scientific approach. “The relationships between researchers, farmers and water managers are critical to the success of the project. We are hoping to develop a shared perspective of the longevity of the resource, so it’s vitally important that the science makes good clear sense to the wider community of the region.”