South West groundwater areas

The south west region of Western Australia is experiencing significant regional development and a drying climate. This means there is a growing demand for a shrinking resource.

Water resource management requires a good understanding of how much water can be used without undesirable changes to the environment, communities and business. The Department of Water has improved this understanding for the South West through the implementation of a program of investigation that was part funded by the Australian Government's $12.9 billion Water for the Future initiative

The project investigated groundwater resources and related water management issues in the Bunbury, Busselton-Capel and Blackwood areas, including the Swan and Scott coastal plains and Blackwood Plateau.

What were the outcomes of the projects?

The final report – Water for the future – South West Groundwater areas management plan summarises the implementation and findings of the project. The most significant findings and management implications for the project areas were:

• Better data and use of data has led to an increased robustness in both regional and local models. It has also increase our understanding of ground and surface water interactions and our ability to set future allocation limits (consumptive pools) with greater precision.
• Increase understanding of the recharge system revealed that there is more recharge systems than previous work had indicated.
• We have provided the community and decision making agencies with confidence in the dependence of our data and the validity of our allocation planning decisions.

Through this project we have also:

• improved our understanding of the shallow groundwater
• constructed a local scale groundwater flow model on the Swan coastal plain
• improved recharge estimation on the Blackwood Plateau
• improved our knowledge of the hydrogeochemistry of the South West groundwater area's (SWGA)
• improved our understanding of the shallow groundwater and river ecology
• investigate the deep groundwater system and improved the groundwater model
• improved out knowledge of the value of water for culture, society, and the environment

What were the products generated through the project?

The following are reports completed and published:

• Analysis of the lower Blackwood river and tributaries flow, groundwater and climate relationships and recommendation of management triggers, Sept 2008
• Swan Coastal Plain Groundwater modelling
• 2007 vegetation Monitoring of groundwater dependent vegetation – southern Blackwood Plateau and Eastern Scott coastal plain
• 2007 vegetation monitoring – Swan Coastal plain (Bunbury, Busselton-Capel Groundwater areas)
• Groundwater level analysis for the southwest groundwater areas
• 2008 Monitoring of groundwater dependent vegetation – Southern Blackwood plateau and Scott Coastal plain.
• 2008 Vegetation Monitoring – Swan Coastal Plain (Bunbury, Busselton-Capel Groundwater areas)
• 2009 Monitoring of groundwater dependent vegetation – Southern Blackwood plateau and Scott coastal plain
• Vegetation monitoring Swan Coastal Plain (Bunbury, Busselton – Capel Groundwater Areas)
• Migration patterns of fishes of the Blackwood River and relationships to groundwater intrusion, Nov 2009
• The Social Values of South West Water resources, June 2009
• Inter jurisdictional analysis of community based governance arrangements for water resource management in Western Australia
• Model for community self management of water options development revision one, Feb 2009

We also produced the following unpublished reports. They include highly technical reports, chemical analysis results; bore drilling data and internal DoW policies.

• HEC-RAS and river analysis package (RAP) modelling of the Blackwood River, May 2010
• Bore completion report for the southwest regional reconnaissance investigation, HR 287
• Development of a conceptual model for the confined aquifers in the Southwest Groundwater Areas using PETREL.
• SWAMS model upgrade and use
• Map plantations (map)
• Position Statement – Self supply irrigators forming as an irrigation service provider
• Guidelines for Water users group, Sept 2009
• Scott coastal plain – Recommended Monitoring & Reporting programs
• Ecohydrological status and vulnerability of GDE in the southwest, May 2010
• Bore completion report: Swan Coastal Plain Stratigraphic drilling program between Bunbury and Dunsborough, HR289
• Southwest groundwater areas – Shallow groundwater systems drilling activity, Nov 2009
• Bore completion report: Scott Coastal Plain, HR296
• Acid Sulfate soil survey of selected wetlands on the Blackwood Plateau and Scott Coastal Plain.
• Strategic Policy – Managing water interception by plantation forestry in Western Australia.
• Scott River Licence Review (Summary report only)

Members of the public who are interested to access information within the reports are invited to contact the Department of Water Library on 63646425. Where reports contain confidential information, the department will provide a summary report upon request by the public.

How will the information be used?

This information will directly support improvements to future management of the resource. It will make a substantial contribution to the next water management plan, due after these projects are completed.

A combination of robust science and information from stakeholders and the community about economic, environmental, social and cultural water issues will be used to prepare the next water resource management plan for the South West groundwater areas. The water allocation plan will help secure water for the South West area, in line with the requirements of the National Water Initiative.