Salinity Province 80, Mornington

The Mornington Salinity Province is a small province on the Mornington Peninsula, about 50 km southeast of Melbourne, about 0.5% of which has been mapped as saline. Landuse is currently about 30% urban and 70% rural, including grazing on improved pasture and high intensity horticulture.

There are projected increases in both urbanisation and intensive horticulture, which will have significant effects on catchment hydrology and therefore soil & water salinity. Two main local to intermediate scale Groundwater Flow Systems (GFSs) occur within this province; the older (Palaeozoic) and deeply weathered ‘Mornington’ Group fractured bedrock systems; and the overlying, younger (Neogene) and larger outcropping ‘Brighton Group’ sediments. Groundwater in the Mornington Group GFSs is considered of low to moderate salinity risk and ranges from 1000 mg/l to 8000 mg/l, while those in the Brighton Group GFSs range from 500 mg/l to 7000 mg/l and are of moderate to high risk. The major assets at risk from both GFSs include streams, engineering and urban infrastructure and agricultural land.

Treatment options in both systems include; biological management (eg. perennial pastures); engineering intervention (eg. surface and subsurface drainage) and ‘living-with-Salt’ (eg. salt tolerant pastures).