Project goal:

Secure long term water supplies for the region.


In planning and construction

Delivery Date:


What's happening?

The Warren Blackwood regional water supply scheme supplies the towns of Manjimup, Bridgetown, Nannup, Greenbushes, Boyup Brook, Balingup and Hester. In early 2022 it was expanded to also supply Mullalyup and Kirup with the completion of the Greenbushes to Kirup pipeline.

Historically relying on independent local dams for its water source, the now integrated scheme relies on groundwater supplementing dams due to the impact of climate change. 

As climate change continues to impact the yield and quality of surface water, it is necessary for us to plan diligently to ensure local communities can continue to have access to secure drinking water supplies.

As a result, we are currently undertaking a water supply planning review for the Warren Blackwood scheme which will involve preparing a Source Development Plan. Visit Warren Blackwood water supply planning to find out more and have your say. 

The scheme may also be expanded to include supply to Pemberton, Northcliffe and Quinninup. Water source planning is currently underway in Pemberton to inform this decision. 

Since 2009 we have been working to create the now integrated scheme that provides secure, high quality water to Warren Blackwood communities. As such, there are some projects in planning or delivery that are already focussed on this. Infrastructure will be extended and upgraded in accordance with future demand growth in the area.

Why is this happening?

The South West’s water supply has traditionally relied on dams - a single dam supplying a single town.  The south west of Western Australia has been significantly affected by climate change through declining rainfall. The dam sources are now becoming unreliable due to decreased streamflow and human activity within the catchment, which in turn is creating water quality issues.

Water Corporation is responding to this new reality in a number ways including developing more robust, integrated drinking water schemes.

When is this happening?

Current projects under construction or in the planning phase for the Warren Blackwood water supply scheme:

  • Warren Blackwood groundwater treatment plant and transfer upgrade - We are planning to construct a new groundwater treatment plant near Nannup to treat groundwater from the bore, as well as upgrade the bore and pump stations. The new treatment plant will remove the iron and manganese from this source. Currently the groundwater from this bore is transferred to the dams which allows the iron and manganese to settle out naturally. Storing groundwater in the dams leads to the loss of water from the system due to evaporation. Consequently, treatment of the groundwater allows the dams to be bypassed as required in the future, reducing the amount lost to evaporation and needing to be abstracted
  • Millstream Dam bypass - To manage water quality concerns, this work will allow bypass of the Millstream Dam. More information can be found on the project page located here. 
  • Hester Dam catchment mitigation - Hester Dam is important during the summer for supply to Hester and Boyup Brook when demand in the scheme exceeds the supply capacity to Bridgetown. This project will allow for management of summer storm inflows while still maintaining supply to Hester and Boyup Brook. Alternative options to divert runoff to the dam and treatment of the water are being investigated for implementation.
  • Groundwater investigations - To support our planning work, there are also several projects active within the Warren Blackwood area to provide detailed information regarding available groundwater sources in the area. These projects include groundwater investigations in Manjimup, Pemberton and Nannup. 

Various projects have already been completed in the scheme upgrade, including:

  • Greenbushes to Kirup Link – a 16 kilometre pipeline between Greenbushes and Kirup is due to be completed by April 2022. This will secure the supply to Balingup, Kirup and Mullalyup and remove the need of water carting from Donnybrook. More information can be found on the project page located here.
  • Millstream-to-Greenbushes pipeline – a new 16.2 kilometre pipeline between Millstream Dam and the town of Greenbushes commenced in November 2013. Construction on this project was completed at the end of January 2017. Commissioning of this new pipeline, with water being supplied into Greenbushes was completed on 1 March 2017. Two new pump stations and two one million litre storage tanks were also constructed as part of this work. More information can be found on the project page located here. 
  • Hester Dam remedial works – an upgrade to Hester Dam was completed in April 2011, ensuring the reservoir can continue to operate at full capacity. This project involved modifications to the dam embankment and new outlet works.
  • Hester-to-Boyup Brook pipeline upgrade – works to duplicate the existing 9 kilometre pipeline between the Hallett tanks and Boyup Brook were completed in October 2015.
  • Doubling the capacity of Millstream Dam – works to upgrade the Millstream Dam from 0.45 billion litres to 1 billion litres capacity were completed in January 2013. The upgrade to the Scheme’s central storage component enables capture of more water during wet years, ensuring adequate surface water storage capacity.
  • Manjimup supply from Nannup Bore – in June 2013, Manjimup joined the Scheme following the construction of a pipeline to link the Nannup bore to Manjimup Dam. Whilst the town’s two dams will remain the principal supply source for Manjimup, the new pipeline is now supplementing Manjimup Dam with groundwater as required, securing water supply for the town even in the driest of years.
  • Yarragadee Bore – a new bore near Nannup was completed in 2009 and has since been used to boost supply to Bridgetown, Boyup Brook and Hester via Millstream Dam when needed.

Water conservation

While this infrastructure will guarantee a safe, reliable and sustainable drinking water supply in an increasingly dry climate, demand management remains a vital aspect of our strategy to deliver long-term climate resilience.

To support achievement of this objective, water efficiency and other compliance measures will continue to be complemented by educational initiatives and partnerships as required. Information on the current Waterwise Towns program can be found here.

Communities in the Warren–Blackwood are commended for embracing water conservation efforts to date.

Contact us

Kristy Lind - Community Engagement Specialist

Phone icon (08) 9420 2570 (business hours)

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