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What is groundwater salinity?

What is groundwater salinity?

Natural groundwater salinity can vary greatly across an aquifer (horizontally and vertically) and over time.  It can be measured in either Electrical Conductivity (EC) or Total Dissolved Solids (TDS). You will need to consider the salinity of the groundwater in your bore before you use it.  Groundwater can be desalinated to ensure it is fit for purpose, however this can be expensive. It is not recommended that people drink untreated groundwater.

Groundwater suitability for use based on salinity

Salinity Suitability for stock watering Suitability for irrigation
EC (µS/cm) TDS (mg/L)
<300 <180 Suitable for all stock Suitable for most crops and soil types
300-800 180-480 Suitable for most crops (may require leaching for sensitive crops)
800-2,500 480-1,500 Suitable for some crops (requires adequate leaching and may be a problem on soils with poor drainage. Salt tolerance of plants must be considered)
2,500-5,800 1,500-3,480 Suitable only for salt tolerant crops on permeable well drained soils (requires careful management)
5,800-7,500 3,480-4,500 Unsuitable for poultry Suitable only for highly salt tolerant crops on soil with excellent drainage (requires adequate winter rains to leach excess salt from the soil and careful management)
7,500-8,500 4,500-5,100 Unsuitable for poultry and pigs Generally considered too saline for any irrigation
8,500-16,500 5,100-9,900 Unsuitable for poultry and pigs

Generally unsuitable for lambs, calves and weaner stock

16,500-25,000 9,900-15,000 Suitable only for dry mature sheep and cattle (use with caution for cattle not used to high salinity water)
>25,000 >15,000 Unsuitable for all stock

This table provides some indication of agricultural uses for groundwater with different salinity levels (shown in both EC and TDS).

Groundwater does not need to be low in salinity to provide benefit.  For example some surface ecosystems rely on hypersaline (extremely salty) groundwater to survive and thrive.  The State Environment Protection Policy (Groundwaters of Victoria) (SEPP GoV) protects the beneficial uses of groundwater according to salinity levels.

Beneficial uses of groundwater

Beneficial uses Salinity (mg/L TDS)
0-500 501-1000 1001-3500 3501-13000 >13000
Maintenance of ecosystems X X X X X
Potable water supply (desirable) X        
Potable water supply (acceptable)   X      
Potable mineral water supply X X X    
Agriculture, parks and gardens X X X    
Stock watering X X X X  
Industrial water use X X X X X
Primary contact recreation (swimming) X X X X  
Buildings and structures X X X X X

This table shows the beneficial uses of groundwater based in salinity levels.

Salinity across the region

To see how groundwater salinity varies across the region and in different  aquifer, visit our Southern Victoria map.

Page last updated28th April 2015
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