Groundwater models of the South Australian River Murray for the Basin Salinity Management Strategy: A policy and modelling success

The River Murray in South Australia is prone to high salinity due to inflows of naturally saline groundwater. Land use changes have increased the flow of salt from groundwater to the river, as the watertable has been raised by the clearance of native vegetation and the introduction of irrigation. The Basin Salinity Management Strategy (BSMS) 2001-2015 continued policy measures established under the Salinity and Drainage Strategy (S&DS) 1988 and the Murray-Darling Basin Authority, to manage River Murray salinity, including the Salinity Registers, which record estimates of the salt load impact on the river of land use change and engineering works. Since the BSMS was agreed, South Australia has developed a suite of groundwater models to provide impact estimates for the Salinity Registers. This has required long-running and close collaboration between state government groundwater modellers and policy officers and also representatives from SA Water and the Murray-Darling Basin Authority. By working together to understand the policy, data information and modelling needs, there has been progressive improvement to each model that has been recognised by independent model reviewers. The work has ensured the state can deliver on a range of obligations under the Murray-Darling Agreement (Schedule 1, Water Act 2007 (Cth)), South Australia's Strategic Plan (2011), and Water for Good (2010) policies. The groundwater models are updated and reviewed on a five-year rolling basis, ensuring that the models and the Salinity Registers can continue to be refined as scientific understanding, modelling techniques and data acquisition improve.