Indicators of Catchment Condition in the Intensive Land Use Zone of Australia – Rivers in salt hazard

Brief description

It should be noted that this data is now somwhat dated! The proximity of parts
of a river network to saline soils is an indicator of the propensity for
saline river flows. This information can be used to guide catchment scale
planning and management towards land management practices to maintain water
tables at depths well below the surface in near-stream areas. Sensitivity is a
function of how rapidly land-use changes cause hydrological changes affecting
stream flow and groundwater conditions.

The most detailed river data available is the AUSLIG 1:250K TOPO data. This
scale is appropriate to catchment scale analyses and has been used for this
indicator. The saline soils coverage is derived from the Atlas of Australian
Soils (Northcote, 1968), which was mapped at 1:2M scale.

This indicator is calculated as length of stream draining saline soils divided
by total length of stream. The quality and reliability of the data set is
limited by the coarseness of the soil mapping.

Broadly, it is reasonable to expect that if the sources of salt within a
catchment are close to streams, stream water will be more saline than for
areas where salt sources are remote from streams. However, interpretation is
not unequivocal as the hydrologic connectivity of alluvial soils is not
spatially uniform and the quantity of salt within asalt hazard soilsa and its
availability are not defined. The indicator has not been validated against
stream salinity data, but the relationship is easy to understand by users.
Some level of validation could be achieved using the stream reach and
exceedence data when available. The greatest density of high salt risk is in
the north and west-flowing tributary catchments of the Murray and Darling
Rivers, most notably the Broken River, Loddon, Avoca, Murray-Riverina,
Lachlan, Mallee, Wimmera-Avon Rivers, Moonie, Gwydir, Namoi, Castlereagh, and
the Macquarie-Bogan Rivers. The Gawler, Wakefield and Broughton Rivers in
South Australia are shown as in the poor category (high risk). The Burdekin,
Don, Calliope and Boyne River basins in Queensland have an indicated
moderately poor condition. The upper reaches of the Greenough, Blackwood and
Avon River Catchments (WA) have a relatively poor condition.

Data are available as:

* continental maps at 5km (0.05 deg) cell resolution for the ILZ;
* spatial averages over CRES defined catchments (CRES, 2000) in the ILZ;
* spatial averages over the AWRC river basins in the ILZ.

See [further metadata](http://data.daff.gov.au/anrdl/metadata_files/pa_iccilr9ab
__05521axx.xml) for more detail.

Full description

pa_iccilr9ab__05521axx.xml -