The Corangamite catchment lies between the Otway Coast, Ballarat and Geelong in south-west central Victoria. Steeply dissected terrain of the Otway Ranges gives way to low hills and volcanic plains of the Camperdown to Geelong middle area before rising again to the moderate elevations of the northern uplands around Ballarat.
The region experiences a temperate climate with dominant westerly winds, variable cloud, moderate precipitation and cool temperatures. Winter rainfall predominates, while summers are warm and dry. Streams are generally perennial, though with much reduced flows in summer. Rainfall varies greatly across the Region – highest along the Otway Ridge and the northern uplands. The central valley, comprising the Basalt Plain, is in a rain shadow, and experiences much lower rainfall.
Livestock grazing is the dominant land-use in in the south of the Region and dryland agriculture tends to occupy the central valley and northern slopes. There is little irrigation compared with northern Victorian regions. There is a minimal area of nature conservation in the Moorabool and Barwon River catchment areas, but a high level of nature conservation and forest in the Otway Coast Basin. European settlement led to massive changes in land use, including the removal of native grasslands for crops and introduced pastures, as well as woody vegetation removal for agriculture, construction timber, firewood and gold mining requirements.
Salinity has been a natural feature of the Corangamite region for at least 20 000 years. The geologically young age of the volcanic landscape, poor surface drainage and terminal lakes such as Lake Corangamite and Lake Murdeduke testify to the presence of this primary salinity. Approximately 16,700 hectares1 of salinity has been recorded in the Corangamite region (not including large lakes or coastal estuarine areas). About half is primary salinity, with secondary salinity (salinity associated with land clearing and land-use change) a significant threat to land productivity in the Lakes/Plains & Northern Foothills sub-Region.
Over 1200 individually mapped units1 of soil salinity have been recorded in the catchment. These have been grouped into 15 Salinity Provinces (including 12 High priority Provinces) based on geographic and biophysical similarities and to aid in monitoring and reporting salinity risk.
The Corangamite CMA has an extensive range of online materials (maps and documents etc.) which outline the biophysical assets of the catchment, as well as their major risks (including soil and water salinity). This material also outlines the programs and projects currently being completed by the CMA to protect and enhance these assets. An example of this is the online data portal called the Corangamite CMA ‘Knowledge Base’, the link to which can be found at the base of this page.
Provinces displayed in this map are clickable or use the table of links provided
Area of Province (ha)
Recorded Soil Salinity Area 1 (ha)
Soil Salinity Area (% of SP)