Finding salinity solutions in Tasmania

Comparing the mainland's salinity problem with Tasmania's is like comparing apples with oranges. Western Australia doesn't have undulating landscapes like the Apple Isle and it is in this topography that Tasmania finds most of its salinity outbreaks.

So the NRM North region has launched a custom-designed salinity management project to find solutions exclusively for the State's land managers.

Program Manager Stu King said applying salinity management techniques for Tasmania had been limited "by our understanding of the driving forces."

"There's been some great work done on salt-tolerant trees and also grazing on saline lands but the range of solutions is limited," Stu said.

"We need pre-emptive designs for a range of agricultural land uses and for both recharge and discharge scenarios. We also need to keep in check the water entering volatile groundwater systems at recharge sites and maintain production values where that water discharges salt at the surface."

The classic Western Australian salinity case is caused by plant removal, which leads to a rising water table. In Tasmania, the difference is the scale and complexity of groundwater flows, geology, topography and soil characteristics. For example, salinity is evident at the break of slopes and at geological constrictions, both with largely varying characteristics across the state making interpretation of risk an expensive and time-consuming affair.

There's also an increase in irrigation and this additional water to the soil has the potential to mobilise salts and result in saline occurrences.

Funding

Work on the salinity management project was funded with more than $1 million from the Australian and State Governments.

Activities and achievements

Detailed investigations are underway in the agriculturally rich Cressy-Longford region of North East Tasmania. Supporting these investigations are seven demonstration farm sites in the Back Creek Catchment, which will road test plant and soil-based solutions such as surface and sub-surface drainage and trees that intercept water entering into the ground or salt-tolerant species such as lucerne and fescue.

"The real key is in where to apply which solutions and how - a matter that'll be addressed in the future with salinity farm planning modules," Stu said.

"We'll also develop monitoring programs at the farm and catchment scale so landholders and planners can keep an eye on conditions over the considerable time required to identify trends. This includes bores and data loggers as well as advanced methods such as electro-magnetic survey, which shows where the salt is in the soil, and, over time, if it has moved.

"The combination of project investigations, farm planning and ongoing monitoring will help landholders identify potential salinity sites - hopefully before production losses are felt. If salinity issues are identified, a range of solutions will be available."

More information

• Stu King, Program Manager: (03) 6333 7774 or sking@nrmnorth.org.au

Australian Government NRM Team
GPO Box 787
Canberra ACT 2601 Australia
1800 552 008 (toll-free)

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