Salinity Province 132, Whittlesea Craigieburn

The Whittlesea-Craigieburn Salinity Province is a medium sized province centred 30 km north of Melbourne on its northern urban boundary. Current landuse is about 20 % residential with the remainder mostly grazing on improved pastures. Being a major residential development area, its rapidly increasing urbanisation will have significant effects on catchment hydrology and therefore soil & water salinity. The southwestern half of the Province is dominated by Quaternary basalt plains interspersed with distinct scoria cones and contains local to intermediate scale Groundwater Flow Systems (GFSs). The remainder of the province is dissected uplands of mostly Quaternary alluvium overlying Palaeozoic fractured bedrock, both of these units containing local to intermediate scale GFSs.

About 0.25 % of the province has been mapped as saline, most of which is in the basalts, occurring in small depressions on the plains and where it thins out or butts against the bedrock. The remaining salinity is associated with ‘break-of-slope’ discharge in the upland alluvium. Major risks from salinity are to local waterways, agricultural land and urban infrastructure. The generally slow response of the GFSs on both the basalt plains and adjacent uplands, inhibits significant impacts from practical recharge control strategies, making ‘living-with-salt’ (eg. salt tolerant pastures) the most effective management options.