The medium sized Mildura-Colignan Salinity Province covers some 125,000 ha of the Mallee CMA Region.
Salinity occurrence is mostly seen as primary salinity features such as salt lakes and inter-dune swale scalds. Like all other Mallee provinces, a regional scale Groundwater Flow System (GFS) comprising marine and alluvial origin sediments underlies this area. Local to intermediate scale GFSs adjoining the Murray River trench and overlying the regional aquifers, are involved in saline groundwater conveyance to the Murray River, which is being exacerbated by the large area of irrigation development. The natural groundwater discharge is likely influenced by structural controls (geological faults), and the resulting salinity areas are being enlarged by the irrigation development.
Management approaches have involved progressive changes to much higher irrigation efficiency and the installation of saline groundwater interception works along the river that divert salt to evaporation basins away from it.
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