Why are we building a groundwater treatment plant in Nannup?

Storing groundwater in dams leads to loss of water from the system due to evaporation. Since 2010, Millstream Dam and Manjimup Dam have been increasingly losing water due to evaporation and lower levels of rainfall. 

The new treatment plant will remove the iron and manganese from the source allowing the dams to be bypassed and the water to be pumped directly into the scheme. This will reduce the amount of water lost to evaporation.

What is the scope of works proposed through this project in Nannup and Manjimup?

The entire scope of works proposed are:

• A 10 to 12 million litre per day Ground Water Treatment Plant which is proposed at the Thomas Road bore site in Nannup.
• Upgrades to pump stations, new and tanks and pipework at the Thomas Road Nannup bore site, Lindsay Road, Brockman Road and Manjimup Dam bypass pipeline site.
• 800 metres of pipeline to bypass Manjimup Dam. 

Please refer to the maps below for the location of works. 

When will these works be completed?

We are only in the early stages of working through approvals and construction is not expected to start until mid to late 2024 pending no delays. We will keep you updated. 

We conducted land and aerial survey work over the proposed work areas in March 2022 and the engineering design of the proposed infrastructure is now underway. 

We are commencing engagement with directly affected or surrounding landowners and stakeholders where work is being complete. We will continue to engage and inform community throughout the project. 

What are the impacts and how are they being minimised?

Baseline noise monitoring has been undertaken at the existing water storage complex at Thomas Road Nannup. This information has been used to inform the design of the new facility, which will be housed within noise attenuating buildings. Noise levels when the new water treatment plant is operating should be similar to existing noise levels.

To reduce potential visual impacts of the new plant, we are engaging a local revegetation company to assist with native screening planting. The planting once established should reduce the visibility of the Ground Water Treatment Plant for neighbours on the northern side of the Blackwood River. Planting is estimated to take place in Winter of 2024. It may take a couple of years for vegetation to establish and reach optimum screening potential.

Location of Nannup works

Location of Manjimup works near Manjimup Dam

More information

We are also undertaking a water supply planning review for the Warren Blackwood regional water supply scheme which will involve updating the scheme's Source Development Plan. For more information visit www.watercorporation.com.au/warrenblackwood.  Alternatively, please contact Community Engagement Advisor Alyce Nehme alyce.nehme@watercorporation.com.au