Salinity - Impacts & Costs - Tasmania
Tasmania
Dryland Salinity Impacts : Tasmania overview
| Assets | 2000 | 2020 | 2050 |
|---|---|---|---|
| Agricultural land (ha) | 53 000 | 69 500 | 93 600 |
| Wetlands of international significance (number) | 6 | 6 | 6 |
| Wetlands of national significance (number) | 44 | 44 | 44 |
The assessments framework used in Tasmania was unable to determine the degree of impact on biodiversity, nor quantify the impacts on infrastructure or water resources.
Impacts on agriculture have been determined by inference, that is, it is assumed that if a land system has any known outbreaks of dryland salinity then all occurrence of that land system across Tasmania also have a potential for developing dryland salinity.
The above table identifies wetlands that occur within land systems that are known to have incidence of dryland salinity. No investigation was undertaken to assess direct impact on wetlands.
What, and how much, agricultural land occurs in areas at high risk from dryland salinity?
There is about:
- 1 950 000 ha of agricultural land,
- 1 410 000 ha cleared
- 540 000 ha uncleared
- 100 000 ha irrigated
- 75 000 ha cropped
of which about 53 500 ha were possibly salt affected in 2000. Thus, about three percent (3%) of agricultural land may be salt affected.
Assuming an enterprise mix of 80% extensive and 20% cropping , and that in 1992 the average regional gross margin for this mix was $250, then the total Gross Margin for the same area as that assumed to be salt affected would have been $11 250 000. Assuming salinity continues to rise and decreases production by 40%.
| Estimated production losses due to salinity ($) | |||
|---|---|---|---|
| Annual increase |
Year | ||
| 2000 | 2020 | 2050 | |
| 1.5% | 5 350 000 | 6 955 000 | 9 362 500 |
| 3.0% | 5 350 000 | 8 560 000 | 13 375 000 |
What biological resources occur in areas of high dryland salinity risk?
Biodiversity
The Flinders and Northern Midlands BioRegions are potentially the most affected.
The following occur in land systems containing areas of salinity and are considered to be of medium to high risk of rising salinity:
| Wetlands: | 132 |
| National significance | 44 |
| International significance | 6 |
| Reserves | 25 |
| Vegetation - non forest | 12 |
| Vegetation - forest | 12 |
| Flora species | 44 |
| Fauna species | 17 |
For more detail please refer to the Tasmania Dryland Salinity Assessment 2000 report.
What water resources occur in areas of high dryland salinity risk?
Water Quality
The only quantifiable impact is that on water in the Coal River in the South East Irrigation Scheme which is at times at Electrical Conductivity (EC) threshold levels which make water risky to use for irrigation.
For more detail please refer to the Tasmania Dryland Salinity Assessment 2000 report.
What infrastructure occurs in areas of high dryland salinity risk?
Ten Local Government Areas contain 95 per cent of the land thought to be salt affected, and four contain 80 per cent.
These four include 6 000km of roads which cost $19 000 000 annually to maintain including associated bridges.
A very small proportion of these may be damaged by dryland salinity as there is no evidence at present and little expertise to estimate risk.
There is some evidence of damage to four golf courses which is being remediated at minimal cost, and to some sports ovals which has not been addressed. No assessments have been made on adjacent holdings.
Further information
- Tasmania Dryland Salinity Assessment 2000 report
- Australian Dryland Salinity Assessment 2000 report
- National Technical Overview Report of the State-based dryland salinity assessments
- Australian Groundwater Flow Systems Report
- Tasmania Department of Primary Industries, Water and Environment
- National Dryland Salinity Program
- National Action Plan for Salinity and Water Quality
Link to Map maker to make a map using this information.
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