Salinity Province 6, Barwon Downs

Thumbnail image showing the location of Barwon Downs Salinity Province in Victoria The Barwon Downs Salinity Province occurs on thick marine deposits called the Gerangamete marls (a carbonate mudstone sedimentary rock) that produces slow flowing local Groundwater Flow Systems. Groundwater is in the salinity range 1500 to 6000 mg/l and high watertable areas and soil salinity tends to be found along drainage depressions and associated river flats.

Management options should focus on the avoidance of areas with high watertables and poor drainage to protect waterlogged soils and tolerant vegetation from damage. Perennial pastures may have limited effectiveness due to the higher rainfall, so suitable waterlogging and salt tolerant pasture species should be sown. Some success seems to have been achieved with tree belt plantings that intercept and use deeper lateral flowing groundwater near discharge areas. High watertables also pose a threat to parts of the southern rural/urban fringe of Colac during higher rainfall periods.

Province Attributes

Catchment Management Region:	CORANGAMITE
Priority Status:	High
Province Area:	58,950 ha
Recorded Soil Salinity Area ¹:	1,279 ha
Dominant Surface Geology Type:	Sedimentary
Influence of Geological Structure on Salinity Occurrence/s:	Possible
Relevant Geomorphological Mapping Units (GMUs):	3.3., 6.2.X
Predominant Groundwater Flow Systems (GFSs):	Regional & Local/Intermediate
Relevant Irrigation Areas:	N/A

Barwon Downs Salinity Province Map

A detailed map showing Barrabool Hills Salinity Province

Links to further reading and material related to the Corangamite Salinity Province

Groundwater Flow Systems (GFS) in the Corangamite CMR

For further information relating to groundwater levels and salinities in this Province please see: Visualising Victoria's Groundwater (VVG)

¹ Please Note: The ‘Recorded Soil Salinity Area’ indicated in the Salinity Province Attribute Table, comprises the total geographic area that has been mapped as having, or showing symptoms of, dryland soil salinity at some time (past or present). As dryland salinity occurrence in the Victorian landscape exhibits many different levels of severity and can change due to climate, landuse and vegetation, previously mapped areas may no longer be showing symptoms. In addition, as not all parts of the State have been mapped, or mapped in the same way, the mapping may not have captured some occurrences.

The soil salinity mapping used to calculate this ‘area’ does not cover irrigation regions. In irrigation regions, depth to watertable and watertable salinity mapping has been used to convey the threat of high watertables on soil waterlogging and/or soil salinisation and these areas are not included in this ‘area‘ calculation.

Please contact the Department, your Catchment Management Authority or your rural water provider for more information about salinity in your location.

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