Victoria's Groundwater Resource

The suitability of groundwater resources is determined by both the quality of the water and by the available yield.

Groundwater Quality

The map of Groundwater Resources differentiates five quality classes of groundwater, based on salinity:

The best groundwater (less than 1,000 mg)/L TDS) - suitable for drinking and for most domestic, industrial and irrigation purposes.
1,000 to 3,000 mg/L TDS - may be used for some domestic and industrial purposes or for irrigating salt tolerant crops.
3,000 to 7,000 mg/L TDS - suitable only for stock watering.
Greater than 7,000 mg/L TDS - suitable only for sheep.
Greater than 14,000 mg/L TDS - too saline for any use.
By comparison, seawater contains about 35,000 mg/L TDS.

Almost half of the total volume of groundwater, or about 480,000 ML, is considered to be fresh while 35% is marginal in quality, 13% is brackish and 3% is saline.

Groundwater quality is generally good in the eastern half of the State and marginal in the Port Phillip region.
In the south-west, divertible resources tend to vary from very good to marginal quality while the smaller minor sources tend to be brackish.
Groundwater salinity causes problems in the river basins which drain to the River Murray in the north-west quarter of the state.
Groundwater in the Mallee and Wimmera regions is particularly saline. The use of groundwater for economic purposes is seriously limited in many parts of these regions.

Groundwater Resources Map

This map differentiates 5 quality classes of groundwater, based on salinity levels. These classes are further differentiated by yield rates. It is based on a map originally developed for the Atlas of Victoria (1982).

The map shows only one aquifer at any one point, usually the Upper Tertiary sand or limestone. These are the aquifers most developed or likely to be developed.

Total Dissolved Solids (TDS)
TDS (total dissolved solids) is a measure of the concentration of dissolved solids in a water sample. These are predominantly salts, but other particles, such as algae or non-conductive ions, may also affect this reading.

Electrical Conductivity (EC) of water is a measure of the conductivity of a solution. It therefore provides an indicator of the level of dissolved salts in a water sample.

EC and TDS usually exhibit a strong correlation for a particular type of water. For most Australian inland waters the relationship is:

EC (µS/cm) = TDS (mg/L) * 0.6

See also...
Groundwater Beneficial Use
This page maps the water quality, or Beneficial Use, of groundwater across Victoria, according to published EPA Beneficial Use segments.
Maps are presented for the watertable aquifer, and the three deeper aquifer systems.

Related Links

The DSE Groundwater Notes Series (external link) provides a series of information notes on groundwater occurrence in Victoria (including the Highlands, Otway Basin, Gippsland Basin, Murray Basin, Westernport Basin and Port Phillip Basin).

Sources:
R.E. Holmes, 1982, Chapter 8:Water Resources, IN: J.S. Duncan (Ed.), Atlas of Victoria, VGPO
Water Victoria: A Resource Handbook, Dept. Water Resources, 1989
Water Victoria: An Environmental Handbook, Dept. Water Resources, 1989
Water Victoria: The Next 100 Years, Dept. Conservation & Environment, 1991

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