We deliver programs to address the impact of salinity in the Shepparton Irrigation Area (SIR), with the aim to protect regional assets and deliver economic, social and environmental benefits.
Land salinisation can occur naturally in the environment when saline water logging results in concentrated levels of salt on the surface (scalds) or in subsoil (seeps). The major concern within the SIR, however, is with secondary or induced salinisation resulting from changes to the vegetation cover. The removal of the deep rooted native vegetation and its replacement, largely by shallow rooted annual crops and pastures, has resulted in a significant reduction in vegetation water use and increased quantities being added to groundwater, raising the watertable. With the combined introduction of irrigation, these have increased the quantity of water being added to groundwater, raising the watertable.
The main driver behind rising shallow watertables in the SIR is rainfall on a wet catchment.
As the groundwater level rises, naturally-occurring salts are dissolved and brought towards the surface, where the salt is concentrated by evapotranspiration. Plants, like other organisms, have set tolerance levels for salinity. Once these limits are exceeded it is expected that symptoms such as a decline in health or growth rate will be experienced.
To reduce the impact of salinity, we operate and manage a network of groundwater pumps to provide sub-surface drainage in the SIR. In the Campaspe West, Nyah, Tresco and Woorinen irrigation areas we provide a service to collect sub-surface drainage discharge from private properties. The cost of providing these services is recovered from a mixture of direct beneficiaries and local government.
More information about salinity risk management and shallow groundwater use in the SIR is available on the GBCMA SIR Salinity Watch website.