Salinity Province 23, Cranbourne

The Cranbourne Salinity Province covers a small area of low coastal plains, about 40 km southwest of Melbourne. Current landuse is about 50% urban and 50% rural (dominated by animal grazing and high intensity horticulture). However, there are projected increases in both urbanisation and intensive horticulture, which will have significant effects on catchment hydrology and therefore soil & water salinity.

Only a small amount (~0.3%) of the province has been mapped as saline, all of which is associated with the local and intermediate scale Groundwater Flow Systems (GFSs) of the Brighton Group Sediments. These GFSs cover most of the province and consist of largely unconfined aquifers in unconsolidated gravels to fine sands, and in the underlying thin veneer of young (Neogene) fluvial sandstones and siltstones. Groundwater salinities range from 500 mg/l to 7000 mg/l and are considered to be of moderate to high risk, with the major assets effected being urban infrastructure and the remaining agricultural areas.

Treatment options include both biological management (eg. perennial pastures and tree planting) and engineering intervention (surface and subsurface drainage). ‘Living-with-salt’ (eg. salt tolerant pastures) should also be considered.