Strategies for managing salinity

The Water Resource Recovery Program was focused on scientific investigation, planning and implementation to achieve salinity reductions in key water resource recovery catchment (WRRC) areas:

• Mundaring Weir Catchment Area*
• Wellington Dam Catchment Area (includes the Harris River Dam Catchment Area*)
• Warren River Water Reserve
• Kent River Water Reserve
• Denmark Dam Catchment Area*

*Denotes a public drinking water source area.

The Salinity Action Plan (1996) identified the rivers as current or future water sources that were expected to deteriorate to beyond recovery from salinisation without active intervention and management.  The objective of the program was therefore to reduce or maintain stream salinity at a drinkable standard.  

A targeted investment approach for the management of salinity in the WRRCs was implemented, which included new predictive modelling approaches and improved understanding of hydrology. This modelling showed for the first time that it was possible to recover certain catchments from salinity. 

This included a comprehensive investigation of stream salinity in south-west Western Australia. The Stream Salinity and Trends Status report was subsequently published in 2005. This report included salinity and hydrological data for the entire South West land division and is still utilised today as a guide to the salinity status of South West rivers.

The modelling and research program resulted in the release of Salinity Situation Statements for each catchment area. This detailed how and where salinity originated in each catchment and also set guidelines for future salinity mitigation work.

Once the Salinity Situation Statements were developed, Water Resource Recovery Strategies were developed for the WRRCs. The goal was to evaluate the effectiveness of the recovery strategies and offer information on the salt status at present and for the future salinity management strategies.

Of the five WRRCs, only the Harris River (part of the Wellington Dam Catchment Area) remains fresh and stable due to the very low levels of cleared land within that catchment.

The Wellington Dam itself is moderately saline, averaging around 1000–1500 mg/L. Water from the Wellington Dam is highly valued and utilised for power generation and irrigation. The Mundaring Weir and Denmark River Catchment areas are marginal and generally fluctuate around the 500 mg/L potable level – dependent on rainfall and streamflow.  

We currently monitor these catchments carefully for any changing land use that may affect salinity levels in addition to regulating clearing through the administration of the Country Areas Water Supply Act 1947 Part IIA Clearing Controls.

We have a good understanding of the scale of intervention needed and in some cases blueprints (recovery plans) to recover water supplies if required.

To find out about the current drinking water quality in Western Australia go to our Water Information Reporting tool.

View our water resource recovery publications

The Land Use Impacts and Catchment Research program focused on the delivery of research and reporting on emerging issues related to the impacts of climate change and vegetation management on surface water catchments.

It operated under several sub-programs:

• Bauxite hydrology – investigating the hydrological impacts of bauxite mining including advising the Mine Management Plan Liaison Group (MMPLG), a mechanism used to implement the Alumina State Agreements.
• Forest Management Plan – audit of the Conservation Commission Forest Management Plan – key performance indicators for management of water resources. This includes providing technical assistance for the development of new Forest Management Plans, a role our department still performs to date. The technical assistance is focused on stream conditions (flow and salinity) and groundwater levels.
• Stream Salinity Trends and Status reporting – to provide an overview and broad analysis of stream salinity in South West Western Australia. A key part of this project is the maintenance of a long term salinity and stream flow monitoring network throughout the state.
• Special studies – extension projects designed to answer key salinity and land use impacts question of state or national significance
  • Development of the Salinity Investment Framework Phase I and Phase II
  • Evaluation of salinity and management of Lake Tooliban and Lake Dumbleyung
  • Yenyening and Qualandary Crossing assessments – an analysis of the hydrological impacts of the causeway across the Salt River
  • Collie Coal Basin – analysis of surface and groundwater and a description of the Muja South water, geology and land use to evaluate impacts of mining on water resources
  • Ord River Sediment Survey – an estimation of the volume of sediments deposited in the old Ord River channel below Lake Argyle since the 1991/92 bathymetric surveys and if the raising of the spillway in 1994 affected sediment deposition.

Management of high groundwater levels, waterlogging of land and increased surface water flows, in the flat landforms of the Wheatbelt, is required to maintain the land as productive farmland or areas of environmental or social value. With 10% of the wheatbelt classified as 'salt effected' we were involved in several initiatives with the objectives to improve water management outcomes for the Wheatbelt and inland South West. The activity areas included evaluation, planning, governance and regulation.

The $4 million Engineering Evaluation Initiative and the $2.8 million Wheatbelt Drainage Evaluation were the construction and evaluation project initiatives used between 2001 and 2009. These implemented fifteen drainage and water management projects across the inland South West. 

The Inland Drainage Initiative resulted in the Policy framework for inland drainage  as a collaboration between the Department of Water and Environmental Regulation (former Departments of Water), Department of Primary Industries and Regional Development (former Department of Agriculture and Food) as well as the Department of Biodiversity, Conservation and Attractions (former Department of Environment and Conservation) with direction from the Wheatbelt Drainage Council, a ministerial committee.

In 2015, the Department of Water and Environmental Regulation (former Department of Water) engaged GHD Pty Ltd to undertake both a high level review of recent Western Australian research into inland (agricultural) drainage and to independently assess drainage works as implemented by the Yarra-Yarra Catchment Management Group for dryland salinity management in the Yarra-Yarra region of the Northern Wheatbelt.

The purpose of the review was to provide practitioners and policy makers with a better understanding of the impacts, benefits and consequences of deep drainage and to support their future decisions. The conclusions and recommendations are provided in Review of inland drainage research and Yarra Yarra regional drainage program.

The independent review concluded that sufficient work had been undertaken by our department to understand and sustainably manage inland drainage.

View our Wheatbelt drainage publications