Groundwater Basins

The groundwater basin or province is the natural hydrogeological unit for delineating and describing groundwater.

The physical structure of Victoria is dominated by a central backbone of fractured rocks known as the Highlands, which form part of the Great Dividing Range. These are consolidated basement rocks of Palaeozoic and Mesozoic age. Groundwater moves mainly through fractures in the rock.

Recharge is generally in the higher areas and discharge to streams in the lower areas, largely as base flow. Usually these upland fractured rocks yield only minor resources.

Over the past 50 million years, substantial erosional deposits of sand, clay, gravel, calcareous sediments (eg. limestone), basalt and coal have accumulated to form gently undulating plains in sedimentary basins south and north of the highland backbone. These unconsolidated sediments can be over 500 metres thick, resting in turn on basement.

The sedimentary sequence contains permeable layers of gravel, sand or limestone. These layers act as aquifers in which water is stored, or slowly moving through.

These porous sediments host the major aquifers yielding useful supplies of water. The Gippsland Basin and Otway Basin are the major basins south of the Great Dividing Range, while the Port Phillip Basin and Westernport Basin are important smaller basins. The dominant basin in the north, the Murray Basin, includes important sub-basins such as the Goulburn, Broken, Ovens, Campaspe and Loddon.

This map shows Victoria’s 5 major sedimentary basins which host the major aquifers yielding useful supplies of groundwater. Clicking on this map will provide information relating to the groundwater basins.

Drilling Investigation Bore
in the Murray Basin, 1987

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