Title
Australia Dryland Salinity Assessment Spatial Data (1:2,500,000) - NLWRA 2001

Custodian
National Land and Water Resources Audit

Jurisdiction
Commonwealth

Description
Abstract
The maps represent a compilation of dryland salinity risk and hazard mapping for 2000, 2020 and 2050. The map shows the broad distribution of areas considered as having either a high salinity risk or a high salinity hazard. 

In southern Australia where groundwater level and trend data are available, assessments that are more confident have been possible. However, in northern Australia groundwater data for trend analysis are very sparse or non-existent. In these regions, salinity assessments have been based on the presence of geological, landscape, regolith, land use and climate attributes which are the prime drivers of salinity. This national map provides a basis for identifying those regions where more detailed assessments are warranted, and where land use changes should be targeted if the risks are to be managed.

The bulk of non-agricultural areas in Western Australia, South Australia and western New South Wales were considered to have a very low salinity risk and were not assessed.

Please note that the Commonwealth and all suppliers of source data used to derive the maps of "Australia, Forecast Areas Containing Land of High Hazard or Risk of Dryland Salinity from 2000 to 2050" do not warrant the accuracy or completeness of information in this product. Any person using or relying upon such information does so on the basis that the Commonwealth and data suppliers shall bear no responsibility or liability whatsoever for any errors, faults, defects or omissions in the information. 

Search Word(s)
WATER Salinity
LAND
GEOSCIENCES

Geographic Extent Name(s)
Australia

Geographic Extent Polygon(s)
* North: -9 
* South: -44 
* East: +154 
* West: +112 

Data Currency
Beginning date
1998

Ending date
2050

Data Status
Progress
Complete

Maintenance and Update Frequency
Not planned

Access
Access Constraints

All products derived from these data must include the disclaimer:

The Commonwealth and all suppliers of source data used to derive the maps of "Australia, Forecast Areas Containing Land of High Hazard or Risk of Dryland Salinity from 2000 to 2050" do not warrant the accuracy or completeness of information in this product. Any person using or relying upon such information does so on the basis that the Commonwealth and data suppliers shall bear no responsibility or liability whatsoever for any errors, faults, defects or omissions in the information. Any persons using this information do so at their own risk.

Stored Data Format
DIGITAL - Arc/INFO polygon
Projection: Geographic
Datum: GDA94

Available Format
DIGITAL - Arc/INFO export

Data Quality
Lineage
NSW:

Areas of risk are based on groundwater levels and air photo interpretation. The data show actual areas where dryland salinity or watertables less than 2 meters have been measured. Every delineated area is underpinned by either air photo data or by one or more groundwater bores. The area at risk is conservative due to limitations in the air photo and bore data.

2000 - based on NSW DLWC Aerial Photo Interpreted salinity outbreak mapping of salinity outbreaks for 1990's plus depth to watertable modelling results for the Murray-Darling Basin and coastal catchments.

2020 and 2050 - based on NSW DLWC Aerial Photo Interpreted salinity outbreak mapping of salinity outbreaks for 1990's plus depth to watertable modelling results extrapolated to the year 2020 and 2050 for the Murray-Darling Basin within NSW. 

Note: There was no modelling of the hazard of dryland salinity in coastal NSW catchments for 2020 and 2050 due to the paucity of groundwater data on which to make the estimates. The forecast area of high hazard in coastal catchments in 2020 and 2050 was mapped as the same as the areas of high hazard in 2000.

TAS:

2000 - Represents regions depicted as "severe" and "derived areas" of salinity in the "Land Systems containing Areas of Salinity in 2000" data provided the Tasmanian Department of Primary Industries, Water and the Environment. 

2020 and 2050 - Forecast hazard of dryland salinity was mapped as the same as the areas of high hazard in 2000.

SA:

2000 - Derived from areas of secondary salinity. Mapped by the South Australian Department of Primary Industries and Resources. Secondary salinity is the salinisation of land and water resources due to land use impacts by people, and includes that due to watertable rises from dryland management systems or irrigation systems. The South Australian estimates of current extent are better estimates of affected land than exist for other states.

A linear trend was applied over the 50 year period - based on the trends to the Year 2000.

2020 and 2050 - Predictions from the South Australian DPIR based on extrapolation of field survey and groundwater trend data from representative catchments across agricultural regions. 

VIC:

2000 - The areas of high hazard in 2000 are derived from areas with watertable depth < 2 metres in the mapping of estimated water table depth as at 1998 by Sinclair Knight Merz.

2020 and 2050 - The areas of high hazard in 2020 and 2050 are derived from areas where watertable depth is forecast to be less than 2 metres under the worst-case groundwater trend scenario.

Large contiguous areas of forest or woodland (mostly public land) were excluded from the analysis due to the lack of groundwater data and generally low threat of salinisation. 

WA: 

2000 - Areas identified as high risk are defined from mapping by Agriculture WA as areas within 2 metres of the surface with a rising or flat trend, and areas between 2 and 5 metres of the surface with a rising trend.

A linear trend was applied over the 50 year period - based on the trends to the Year 2000.

2020 and 2050 - Areas forecast with a high hazard of dryland salinity are defined from areas of forecast high risk of shallow water table. High risk is based on areas forecast to have groundwater within 2 metres of the surface with a rising or flat trend, and areas between 2 and 5 metres of the surface with a rising trend. 

QLD:

The hazard map for 2050 was produced by collating available data for geology, Atlas of Australian Soils, elevation, land use change and potential excess rainfall. It reflects potential dryland salinity areas related to the extent of land use change. There are no State-wide data which capture salt storage in the weathered landscape zone. As a result a significant over-estimation of areas at risk is likely to have been made. It should not be directly compared with 2050 predictions using the groundwater trend approach.

Positional Accuracy
This map is a composite product and the positional accuracy depends on the source of the data. It is considered that the national map is useful at approximately 1:2,500,000 scale. 

The issues of reporting scale, monitoring bore distribution and density and data quality and availability need to be recognised when interpreting the results of this national assessment. The assessments undertaken by the Audit provide sufficient information to target more detailed regional activities and scope the impacts of salinity. There are insufficient data to precisely determine dryland salinity outbreak / incidence across Australia.

In southern Australia where groundwater level and trend data are available, assessments that are more confident have been possible. However, in northern Australia groundwater data for trend analysis are very sparse or non-existent. In these regions, salinity assessments have been based on the presence of geological, landscape, regolith, land use and climate attributes which are the prime drivers of salinity. This national map provides a basis for identifying those regions where more detailed assessments are warranted, and where land use changes should be targeted if the risks are to be managed.

Attribute Accuracy

The attributes associated with the coverage are:

AREA - The boundary of a polygon defines a region (often a land system, or grid cell) where a high risk or hazard occurs somewhere within the region. In many cases, less than 100% of a polygon will have a high hazard or risk. The AREA attribute should not be used to calculate and report on total area of high hazard or risk. 

ASSESS_2000 - Forecast areas of high hazard of dryland salinity in 2000. 

AREA_MULTIPLIER_2000 - Area multiplier for the year 2000 is required to adjust the calculated GIS map areas (assuming an equal area projection). This pro-rata approach provides equivalent areas estimates to those reported by the State agencies as area at risk or hazard as published in the Australian Dryland Salinity Assessment 2000 Report by the National Land and Water Resources Audit.

ASSESS_2020 - Forecast areas of high hazard of dryland salinity in 2020.

AREA_MULTIPLIER_2020 - Area multiplier for the year 2020 is required to adjust the calculated GIS map areas (assuming an equal area projection). This pro-rata approach provides equivalent areas estimates to those reported by the State agencies as area at risk or hazard as published in the Australian Dryland Salinity Assessment 2000 Report by the National Land and Water Resources Audit.

ASSESS_2050 - forecast areas of high hazard of dryland salinity in 2050.

AREA_MULTIPLIER_2050 - Area multiplier for the year 2050 is required to adjust the calculated GIS map areas (assuming an equal area projection). This pro-rata approach provides equivalent areas estimates to those reported by the State agencies as area at risk or hazard as published in the Australian Dryland Salinity Assessment 2000 Report by the National Land and Water Resources Audit.

STATE - Three letter State or Territory code

The current or forecast areas of high hazard are not exact, but are sufficiently accurate for a broad-scale national assessment.

Logical Consistency
Arc/INFO was used to undertake a topological consistency check to detect flaws in the spatial data structure and to flag them as errors for correction. This check ensures that all classified polygons are closed, nodes are formed at the intersection of lines and that there is only one label within each polygon.

Completeness
Data are complete for agricultural areas in the intensive landuse zone to the extent of current knowledge.

Contact Information
Organisation
National Land and Water Resources Audit

Contact Position
Technical Manager (Data)

Mail Address
GPO Box 2182

Suburb or Place or Locality
Canberra

State
ACT

Postcode
2602

Telephone
02 6257 3052

Facsimile
02 6257 9518

Electronic Mail Address
atlas@nlwra.gov.au

Additional Metadata
Additional Metadata
Area Multipliers

State
2000
2020
2050
NSW
0.14
0.32
0.49
QLD
0.00
0.00
1.00
SA
1.00
1.00
1.00
TAS
0.25
0.33
0.44
VIC
1.00
1.00
1.00
WA
1.00
1.00
1.00

Area multipliers are provided to adjust the calculated GIS map areas (assuming an equal area projection). This pro-rata approach provides equivalent areas estimates to those reported by the State agencies as area at risk or hazard as published in the Audit's Australian Dryland Salinity Assessment 2000 Report.

Victoria

Trends used in this coverage are considered the worst-case trend scenario for Victoria. Method of trend calculation and derivation of hydro-geomorphic units is documented in Sinclair Knight Merz and Agriculture Victoria (2000) Extent and impact of dryland salinity in Victoria. Report to the National Land and Water Resources Audit.

The area identified as having water tables less than two metres depth is considered to represent the currently containing land with shallow water tables. Method of derivation of hydro-geomorphic units and water table surface is documented in Sinclair Knight Merz and Agriculture Victoria (2000) Extent and impact of dryland salinity in Victoria. Report to the National Land and Water Resources Audit.

New South Wales

Integrated Catchment Assessment and Management Centre, Australian National University & Department of Land and Water Conservation, 2000.

National
NLWRA (2000) National Landuse Map (1 km grid cell)

Metadata date
9 February 2001

Additional Metadata

The Australian Dryland Salinity Assessment 2000 is available from the National Land and Water Resources Audit at: http://audit.ea.gov.au/ANRA/land/docs/national/Salinity_Contents.html

Entities/Attributes

ENTITY NAME
aus_salinity.e00

ENTITY DESCRIPTION
An assessment of the risk of dryland salinity in Australia in 2000, 2020 and 2050.

DATA TYPE
Vector

Feature Attribute Name
AREA
Feature Attribute Definition
The boundary of a polygon defines a region (often a land system, or grid cell) where a high risk or hazard occurs somewhere within the region. In many cases, less than 100% of a polygon will have a high hazard or risk. The AREA attribute should not be used to calculate and report on total area of high hazard or risk. 

Feature Attribute Name
ASSESS_2000
Feature Attribute Definition
Forecast areas of high hazard of dryland salinity in 2000. 

Feature Attribute Name
AREA_MULTIPLIER_2000
Feature Attribute Definition
Area multiplier for the year 2000 is required to adjust the calculated GIS map areas (assuming an equal area projection). This pro-rata approach provides equivalent areas estimates to those reported by the State agencies as area at risk or hazard as published in the Australian Dryland Salinity Assessment 2000 Report by the National Land and Water Resources Audit.

Feature Attribute Name
ASSESS_2020
Feature Attribute Definition
Forecast areas of high hazard of dryland salinity in 2020.

Feature Attribute Name
AREA_MULTIPLIER_2020
Feature Attribute Definition
Area multiplier for the year 2020 is required to adjust the calculated GIS map areas (assuming an equal area projection). This pro-rata approach provides equivalent areas estimates to those reported by the State agencies as area at risk or hazard as published in the Australian Dryland Salinity Assessment 2000 Report by the National Land and Water Resources Audit.

Feature Attribute Name
ASSESS_2050
Feature Attribute Definition
forecast areas of high hazard of dryland salinity in 2050.

Feature Attribute Name
AREA_MULTIPLIER_2050
Feature Attribute Definition
Area multiplier for the year 2050 is required to adjust the calculated GIS map areas (assuming an equal area projection). This pro-rata approach provides equivalent areas estimates to those reported by the State agencies as area at risk or hazard as published in the Australian Dryland Salinity Assessment 2000 Report by the National Land and Water Resources Audit.

Feature Attribute Name
STATE
Feature Attribute Definition
Three letter State or Territory code