Salinity Province 93, Pakenham Bunyip

The Pakenham_Bunyip Salinity Province is a small province that straddles the Princess Freeway about 60 km southeast of Melbourne. Apart from its residential western edge, landuse in the province is mostly grazing on modified pasture. However, major residential development is occurring throughout the area, which will have significant ongoing effects on catchment hydrology and therefore soil & water salinity. The southern half of the province is part of the Westernport Plain, consisting of Quaternary alluvium, with intermediate to regional scale Groundwater Flow Systems (GFSs). The province becomes undulating to hilly in the north, where the more complex geology results in many local scale GFSs associated with weathered granite, colluvium and stream alluvium, and local to intermediate scale GFSs in fractured Palaeozoic meta-sedimentary rocks.

Only 0.2% of the Province has been mapped as saline, with most of this located east of Pakenham associated with the weathered granite and colluvium.

The highest impact treatment options include; productive uses of saline land in discharge areas, especially salt tolerant pastures, and recharge control through tree planting and potentially some groundwater pumping in the colluvium.