Report 8

Management of Salinity

Introduction and Background

This audit assessed the management of salinity in the agricultural regions of the South West of Western Australia (WA). This is defined by the area roughly west of a line from Kalbarri to Esperance. We focused on the following lines of inquiry:

1.      Do agencies know the extent and impact of dryland salinity in the South West agricultural regions?

2.      Are efforts to reduce the impacts of dryland salinity in the South West agricultural regions working?

Background

Dryland salinity is a major issue in the agricultural regions of the South West of WA. It adds significant costs to agriculture, causes damage to road, rail and building infrastructure and affects water resources and biodiversity.

It is caused by the clearing of deep rooted native vegetation for shallow rooted annual crops and pasture, which changes the water balance. As water tables rise, salt stored deep in the sub-soil is carried up to the surface and eventually discharged into waterways (Figure 1).

Figure 1 - Depiction of how dryland salinty occurs

By the 1990s dryland salinity was considered the greatest economic and environmental threat to the State[1]. The Department of Primary Industries and Regional Development (DPIRD) estimates that since 2009-10 the opportunity cost of lost agricultural production from dryland salinity has been over $500 million a year and that 25% of cleared agricultural land will be at risk of salinity in the long term. It was also predicted by DPIRD that the cost of protecting water supplies and maintaining infrastructure could be even higher.

Clearing over 18 million of the 21 million hectares of native vegetation in the agricultural regions has occurred in an area that is internationally recognised as a biodiversity hotspot. Salinity has had a significant and long lasting impact on the region’s natural biodiversity and land systems. The threat to the biodiversity is not limited to individual species. The Department of Biodiversity Conservation and Attractions (DBCA) advises that all the remaining remnants of many valley-floor communities (wetlands, shrublands and woodlands) along with their soils could disappear because of salinisation.

In response to community concern the Government released the Salinity Action Plan in 1996 and the State Salinity Strategy in 2000. A Cabinet Standing Committee, chaired by the Deputy Premier, was established with overall accountability for the Salinity Action Plan. A Salinity Council was also appointed by Government to report to the Committee on matters of policy and performance of the Salinity Action Plan. A timeline of government initiatives is detailed in Appendix 1.

In May 2001, a Salinity Taskforce was established by Government to review salinity management in WA. In June 2002, the Government provided a response to the Taskforce report and committed to taking the lead, building on the action plan and the strategy. Between 2003 and 2008, $560 million of Federal and State funds was invested in a range of land management initiatives which included salinity management and water quality programs.

The Soil and Land Conservation Act 1945 is the principal legislation relating to the conservation of soil and land resources, and to the mitigation of the effects of erosion, salinity and flooding. Government agencies and individual landholders have a responsibility to manage dryland salinity as per below:

[1] Western Australian Salinity Action Plan, November 1996
Appreciating and Creating Our History, By Frost and Burnside, page 9

Figure 2 - Dryland salinity management framework

The Commissioner of Soil and Land Conservation can issue a notice to a landholder to take specific action if degradation is occurring or likely to occur. If the land is within a gazetted water catchment or has important biodiversity values, there may be restrictions as to its use under legislation managed by the Department of Water and Environmental Regulation (DWER) and DBCA.

 

 

 
Page last updated: July 29, 2018

Back to Top