Australian Natural Resources Atlas

Natural Resource Topics

Salinity - Impacts & Costs - New South Wales

New South Wales

Location map

Dryland Salinity Impacts : New South Wales overview

An assessment of the impacts of the current and future shallow water on land use and infrastructure was undertaken by digitally overlaying the water table maps with other digital data sets.

The impacts of shallow water tables on land use in summarised in the table below. The largest land use impact is for agricultural areas (cropping, horticultural and pastoral). Under current conditions, the largest areas of agricultural lands affected are within the Murray, Murrumbidgee and Macquarie catchments. There are also large impacts on forestry and remnant vegetation in the Murrumbidgee and Macintyre catchments.

Under future scenarios, there are large increases in remnant vegetation affected by shallow water tables in the Macintyre and Murrumbidgee catchments, and to a lessor extent in the Lachlan and Lake Hume catchments. Currently, there are large impacts in conservation areas within the Namoi, with future impacts in the Murrumbidgee catchment predicted.

Key assets at risk from shallow watertables within the catchments of the Murray-Darling Basin and the coastal catchments of the Hunter and Hawkesbury-Nepean rivers*, New South Wales.

Assets 2000 2020 2050
Cropping land (ha) 28 700 114 445 223 658
Forests (ha) 540 15 348 34 507
Horticulture land (ha) 1000 1 913 4 780
Managed protection areas (ha) 130 186 744
Nature conservation areas (ha) 2400 9 450 35 502
Pasture land (ha) 132400 412 125 927 171
Remnant vegetation (ha) 5 300 17 370 46 514
Built-up areas (ha) 1 182 2 209 3 646
Towns (number) 38 82 125
Highways (km) 130 331 534
Major roads (km) 110 298 701
Minor roads (km) 700 1 959 3 615
Railways (km) 100 226 416
Bridges (number) 20 22 43
Wetlands (directly affected) (number) 9 1 2

* Data for the Hunter and Hawkesbury-Nepean only for 2000.

What, and how much, agricultural land occurs in areas at high risk from dryland salinity?

Table: Estimated areas (ha) with depth of watertable less than 2 m under current conditions and year 2020 and year 2050 scenarios for major catchments of the Murray-Darling Basin and coastal catchments.
Catchment 2000 2020 2050
Lake Hume 127 3 973 19 254
Murray 39 526 168 978 293 191
Murrumbidgee 58 098 286 848 469 500
Lachlan 19 793 38 845 153 264
Macintyre 3 800 25 500 67 224
Gwydir 0 0 2 973
Namoi 2 896 4 288 27 837
Castlereagh 1 197 12 005 174 666
Macquarie 25 072 36 767 90 848
Richmond 155 n/a n/a
Clarence 91 n/a n/a
Bellinger 27 n/a n/a
Manning 34 n/a n/a
Hunter 22 954 n/a n/a
Hawkesbury-Nepean 4806 n/a n/a
Georges-Cooks 13 n/a n/a
Deua 11
Total 180 600 579 224 1 300 807

n/a = not available

The best available estimates of rates of groundwater rise indicate that by 2020 rising watertables will occur in large areas of the Murrumbidgee and Murray catchments. By 2050, large areas of the Lachlan, Castlereagh and Macintyre catchments will also be affected.

Table: Estimated areas (ha) affected by depth to less than 5 m with a rising watertable trend for eastern Murray-Darling Basin catchments.
Catchment 2000 2020 2050
Lake Hume 3 973 12 999 37 496
Murray 168 978 227 187 293 514
Murrumbidgee 156 319 483 300 997 058
Lachlan 72 726 153 105 294 524
Macintyre 24 259 63 871 127 385
Gwydir 661 10 024 24 169
Namoi 10 244 20 427 57 528
Castlereagh 12 015 110 396 243 245
Macquarie 47 548 106 856 324 974
Total 496 722 1 188 163 2 399 892
Table: There are also substantial impacts of dryland salinity and shallow water tables in areas outside the Murray-Darling Basin. Impacts on land use for the two coastal catchments most at risk (Hunter and Hawkesbury/Nepean) are summarised in the table below. The largest impacts on agricultural land and conservation/remnant vegetation are evident in the Hunter catchment.
Hunter Hawkesbury Nepean
Cropping land (ha) 213 29
Forests (ha) 61 0
Horticulture (ha) 470 0
Managed protection (ha) 106 0
Nature conservation (ha) 425 7
Pasture (ha) 18 515 943
Remnant vegetation (ha) 279 6

What biological resources occur in areas of high dryland salinity risk?

Table: Summary of the key environmental assets at risk from shallow water tables within the Murray-Darling Basin, New South Wales
Assets 2000 2020 2050
Forests (ha) 481 15 348 34 507
Managed protection areas (ha) 29 186 744
Nature conservation areas (ha) 1 993 9 450 35 502
Remnant vegetation (ha) 5 038 17 370 46 514
Table: There are also substantial impacts of dryland salinity and shallow water tables in areas outside the Murray-Darling Basin. Impacts on conservation resources for the two coastal catchments most at risk (Hunter and Hawkesbury/Nepean) are summarised in the table below. The largest impacts on agricultural land and conservation/remnant vegetation are evident in the Hunter catchment.
Hunter Hawkesbury Nepean
Forests (ha) 61 0
Managed protection (ha) 106 0
Nature conservation (ha) 425 7
Remnant vegetation (ha) 279 6

What water resources occur in areas of high dryland salinity risk?

The NSW contribution for the recent Murray-Darling Basin Salinity Audit (Department of Land and Water Conservation 1999) provided estimates of future salt loads for the NSW portion of the Murray-Darling Basin (see table below). For many catchments, salt loads are predicted to dramatically increase during the next 50 years, assuming no change in management and a continuation of similar climate variability to that observed in the assessment period. For the major inland rivers in NSW, the most marked increases in total salt loads are predicted for the Lachlan, Bogan, Barwon and Namoi Rivers. The Bogan, Macquarie and Namoi catchments showed the largest increase in stream salinity.

Table: Redistribution of salt load in the landscape by catchment (Department of Land and Water Conservation 1999)
Catchment Median salt load (tonnes per year)
2000 2020 2050
Macintyre at Mungindi 68 000 68 000 68 000
Gwydir near Collarenebri 6 600 7 000 8 500
Namoi at Goangra 50 000 81 000 100 000
Barwon- Darling at Menindee 132 500 215 000 265 000
Castlereagh at end-of-valley 18 400 20 100 36 500
Macquarie at Carinda 32 100 65 500 89 000
Bogan at Gongolgon 24 600 48 000 63 500
Lachlan at Forbes 234 800 290 500 428 300
Murrumbidgee at Balranald 139 000 166 500 180 500

What infrastructure occurs in areas of high dryland salinity risk?

The length and percentage of roads affected by shallow water tables and dryland salinity outbreaks are summarised in table below More detail is available in the NSW Dryland Salinity Assessment 2000 report. On average 1% of roads in the eastern Murray-Darling Basin are currently at risk. This increases to approximately 7% by 2050. Under current conditions, highways only within the Murray, Murrumbidgee, Lachlan and Macquarie catchments are at significant risk. In the next 50 years, largest increases in highways affected occur for the Murray, Murrumbidgee and Castlereagh catchments. The impacts on other major and minor roads follow these trends.

2000 2020 2050
km % km % km %
Dual lane highways
Murrumbidgee 2 1.0 9 4.4 18 8.7
Total 2 0.8 9 3.7 18 7.4
Highways
Lake Hume 0 0.1 0 0.0 0 0.1
Murray 22 5.3 74 17.4 127 29.9
Murrumbidgee 48 2.3 196 9.2 265 12.5
Lachlan 18 1.4 23 1.8 61 4.7
Macquarie 17 1.3 25 1.9 46 3.5
Macintyre 0 0.0 2 0.2 6 0.9
Namoi 0 0.0 0 0.0 2 0.2
Castlereagh 0 0.2 2 0.6 9 2.8
Total 107 1.5 322 4.4 515 7.1
Major Roads
Lake Hume 0 0.0 7 2.8 28 10.9
Murray 23 2.1 120 11.0 233 21.4
Murrumbidgee 30 1.2 120 4.7 186 7.2
Lachlan 10 0.5 23 1.1 139 6.4
Macquarie 21 1.2 25 1.4 46 2.6
Macintyre 0 0.0 1 0.1 3 0.5
Gwydir* 0 0.0 0 0.0 0.0
Namoi 1 0.1 1 0.1 4 0.3
Castlereagh 1 0.2 1 0.2 62 13.8
Total 85 0.8 297 2.8 700 6.6

The length and percentage of railway lines affected by shallow water tables and dryland salinity outbreaks are summarised in the table below. On average 1% of railway lines in the eastern Murray-Darling Basin are at risk. This increases to approximately 6% by 2050. Currently, railway lines in Murray and Murrumbidgee are most affected. By 2020, large increases in railway lines affected occur in the Murray, Murrumbidgee and Macquarie catchments. Beyond 2020, railway lines in the Namoi catchment are also substantially affected.

2000 2020 2050
km % km % km %
Lake Hume 0.0 0.0 0.0 0.0 1.4 3.5
Murray 13.7 3.3 29.9 7.2 44.2 10.6
Murrumbidgee 40.0 2.0 157.3 8.1 218.3 11.2
Lachlan 8.2 0.5 11.1 0.7 77.5 4.8
Macquarie 0.0 0.0 7.8 2.3 7.8 2.3
Macintyre 0.0 0.0 0.0 0.0 0.0 0.0
Gwydir* 0.0 0.0 1.1 0.4 25.3 9.7
Namoi 0.2 0.0 0.2 0.0 1.0 0.1
Castlereagh 16.3 1.2 18.3 1.3 40.0 2.9
Total 78 1.1 226 3.1 416 5.8

Urban salinity is considered a major issue in NSW. The current estimates summarised in the table below, show that on average 2% or 954 ha of built-up areas are at risk, mainly in the Murray and Murrumbidgee catchments. This will increase almost four-fold over the next 50 years. Largest impacts are forecasted for the Lake Hume, Murray, Castlereagh and Macquarie catchments. The total number of towns affected in NSW is 38. This increases to 82 by 2020, and 125 by 2050.

Builtup Areas 2000 2020 2050
ha % ha % ha %
Lake Hume 0 0.0 29 34.6 50 60.2
Murray 87 2.6 235 7.0 548 16.4
Murrumbidgee 847 3.5 1 491 6.2 1 625 6.8
Lachlan 5 0.1 19 0.4 385 7.5
Macintyre 0 0.0 0 0.0 0 0.0
Gwydir* 0 0.0 0 0.0 0 0.0
Namoi 0 0.0 0 0.0 0 0.0
Castlereagh 0 0.0 99 8.7 268 23.5
Macquarie 16 0.2 336 4.9 755 10.9
Total 954 2.0 2 209 4.7 3 631 7.7

There are also substantial impacts of dryland salinity and shallow water tables in areas outside the Murray-Darling Basin. Impacts on infrastructure for the two coastal catchments most at risk (Hunter and Hawkesbury/Nepean) are summarised in the table below. Currently, 2% of all roads in Hunter catchment are currently affected by shallow water tables; twice the percentage calculated for the Murray-Darling Basin catchments. Approximately 3% of all built-up areas within Hunter and Hawkesbury Nepean catchments are affected by shallow water tables and dryland salinity.

Hunter Hawkesbury Nepean
Built-up areas (ha) 60 168
Highways (km) 12 10
Major roads (km) 19 6
Minor roads (km) 71 26
Railways (km) 20 2
Bridges 5 3

Further information

New South Wales Dryland Salinity Assessment 2000

Link to Map maker to make a map using this information.

Before you download

Most publications are downloadable as PDF files. Adobe Acrobat Reader  is required to view PDF files.

If you are unable to access a publication, please contact us to organise a suitable alternative format.

Key

   Links to an another web site
   Opens a pop-up window