In late 1999, the Murray Darling Basin Ministerial Council released the Salinity Audit
of the Murray Darling Basin, which included a review of the 1988 Salinity & Drainage Strategy.
The audit was more sophisticated than earlier work in that it took into account climatic
variations and diversions and used modeling to predict future trends rather than just describing
historical trends. The overall basin audit was based upon predictions undertaken by each state
government (NSW Salinity Strategy 2000).
This audit provided information on salinity trends, river valley by river valley, for salt
mobilisation in the landscape and its expression in rivers. It predicted significant increases
in river salinities and salt loads in the Murray and Darling Rivers and the major catchments of
these rivers. Average river salinities in key tributary rivers were predicted to rise significantly,
endangering their use for irrigation and urban purposes within 20 to 50 years, and about 3.4 million
ha of land in the eastern and southern regions of the Basin will be salt-affected within 50 years
(Murray Darling Basin Commission, 2001).
If no intervention was to occur, the reduction in lower River Murray salinity achieved over the
last decade would be cancelled out within 20 to 30 years, and median salinity levels would exceed
the Australian Drinking Water Guidelines for good quality water within 50 to 100 years
(Murray Darling Basin Commission 2001).
A key finding of the salinity audit was that much of the mobilised salt was not being exported via
the rivers to the sea but rather stays in the landscape or is diverted into irrigation areas and
floodplain wetlands (MDBC Salinity Audit). In addition to an increased understanding of salinity
impacts on assets and values the audit led to the development of methodology for setting salinity
targets within the basin (NSW Salinity Strategy, 2000)