PAST RESEARCH PROGRAMS
Salinity Program
Program Leader: Dr Glen Walker, CSIRO
Land and Water
Core Projects
Publications
A complete list of publications and videos from this program
is available here.
Aim
To develop improved tools, guidelines and knowledge for
catchment managers to apply in monitoring stream salinity
and in controlling salinity inputs to rivers and streams,
particularly in the Murray-Darling Basin
Background
Salinity has impaired the productivity of vast tracts
of Australian farmland. It threatens the health of streams
and rivers that drain both irrigated and dryland salinity
affected catchments. Salinity is also degrading rural
towns and infrastructure, and crumbling building foundations,
roads and sporting grounds. The problem is not under control
— we can expect the effects of salinity to continue
to increase dramatically if we do not find and implement
effective solutions. Most salinity control measures –
such as tree planting and groundwater pumping – aim
to either reduce groundwater recharge or lower existing
water tables. Selecting a successful control measure,
however, is a complex issue. Catchment managers and other
practitioners need to consider the interaction between
factors such as climate, soil type, catchment size and
shape, water-table level, extent of salinisation, and
land use practices.
Dryland salinity in the Murray-Darling Basin and Western
Australia’s wheat–sheep belt affects about
2.5 million hectares, and is spreading at a rate of
3–5% per year. The CRC has made a significant contributions
to dryland salinity research, influencing thinking at
a political and technical level in Australia. The CRC’s
work on historical stream salinities throughout the
Murray-Darling Basin helped provide impetus for the
MDBC’s 1999 Salinity Audit — the beginning
of attempts to link salinity to catchments and start
to build in groundwater processes to regional scale
salinity prediction.
The research within the CRC’s Salinity Program
has focused on the Murray-Darling Basin and in particular
on stream salinisation. The Murray-Darling Basin Commission’s
1988 Salinity and Drainage Strategy is the main political
strategy for the control of salinity. However, it severely
underestimated the contribution of dryland areas on
stream salt loads, focusing instead on the salt exports
from irrigation areas to streams.
The CRC’s research in Project S3 has made a broad
identification of the areas of the Basin affected by
dryland salinity, with its historical stream salinity
and salt load project. This work highlighted the importance
of the upland dryland catchments of the Basin in southern
NSW to the stream salt loads of the Murray-Darling Basin.
Work has also incorporated the development of simple
groundwater and water balance modelling techniques for
prediction of salinity and waterlogging in these areas.
The improved understanding of recharge processes and
water balance terms has allowed estimation of the impacts
of reforestation on stream salinities.
The CRC has been at the forefront of the move to better
utilise the available data from a range of well-studied
catchments, and develop methods and techniques for transferring
this knowledge more widely. Further work by the CRC
on the long-term impacts of land use change on groundwater
processes such as recharge and discharge have enhanced
our understanding of salinity processes for a variety
of catchment types. The CRC has strong links with the
MDBC coordinated Catchment Characterisation project
which has identified 15 different groundwater system
types throughout Australia. It is also making a significant
contribution to the National Land and Water Resources
Audit through its dryland salinity theme case studies,
where groundwater modelling approaches are being undertaken
to provide an understanding of the different processes
of importance across a range of catchment types
With the growing awareness of the need to reduce salt
loads in the Murray-Darling Basin’s rivers, the
CRC has undertaken research into the possibilities for
the reduction of salt loads from irrigation areas to
rivers within the S1 and S2 Projects. Project S1 studied
the saline Barr Creek irrigated catchment (Kerang, Vic.)
to look at how changes in irrigation management would
impact on the salt export from the area. The first part
of the study undertook a detailed field experiment over
3 years, looking at a water and salt balance of an irrigation
bay. The second part used GIS techniques to expand the
understanding of the single bay to a subcatchment area.
Project S2 provided an extremely detailed understanding
of the behaviour of saline disposal basins. These basins
are used as a terminal storage for irrigation drainage
water and salt, thus minimising the salt exported from
irrigation areas, while still controlling waterlogging.
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