Exmouth water source planning
Project goal:
Work is underway to identify a new water source to secure Exmouth's drinking water supply through to 2050.
Status:
In planning
Delivery Date:
Late 2024
What's happening?
Water Corporation have commenced investigations to identify a new drinking water source for Exmouth to meet projected future demand.
The new source will also cater for climate change and secure water supply for the future.
Where does Exmouth currently get its water?
Exmouth's water is supplied from 34 production bores which draw from a groundwater aquifer. The borefield extends for 10km, comprising 6 bores within the Exmouth Town Groundwater Subarea and the remaining 28 bores within the Exmouth Central Groundwater Subarea, located further south of the townsite (see map below).
The existing borefield is designed and operated to abstract water at low rates to mitigate saline intrusion and maintain conditions to support stygofauna habitat across the borefield. The Exmouth borefield relies on heavy episodic rainfall events in summer/autumn and winter rainfall for recharge. The Water Corporation abstracts water under a DWER abstraction licence.
How much water do we need?
With a growing population, it’s estimated Exmouth will need an extra 500 million litres per annum to meet projected demand by 2050.
What options are being considered for a new water source?
The two main options being considered for Exmouth's next drinking water source are:
- Expansion into the groundwater sub area to the south – accessing up to 0.5GL/year of the 4GL/year currently available in DWER’s allocation plan for the Exmouth South Groundwater Sub Area.
- Develop a climate independent small-scale seawater desalination plant - sites have been assessed through a Multi Criteria Analysis which considered the Environmental Protection Authority (EPA) ‘Cumulative Impacts Report’, for new development in the Exmouth Gulf.
When will a decision on the new source be made?
Planning is in the investigations stage, and we’re committed to getting this right. Throughout this stage we’ll be assessing how options can be delivered with the lowest environmental impact, in the required timeframe, and with the greatest long-term benefit to the community.
Engagement with key stakeholders commenced in early 2023, and we will continue to consult with key stakeholders and the community throughout to ensure we understand social, environmental, cultural, heritage and operational requirements associated with each option.
Following thorough engagement, we will complete environmental and heritage surveys and studies to inform a decision on the preferred option (borefield expansion or seawater desalination) which is expected in late 2024.
Water Corporation is the principal supplier of water, wastewater, drainage and some bulk irritation services in Western Australia to homes, businesses and farms. We are regulated by DWER and Department of Health. Supply of water is licensed by the Department of Water.
Water Corporation has licenses with the Department of Water and Environmental Regulation to abstract water from two groundwater subareas. This is through 6 bores within the Exmouth Town Groundwater Subarea and 28 bores within the Exmouth Central Groundwater Subarea, which is located further south of the townsite.
These licenses are due for renewal in January 2027. There are three other groundwater sub areas in Exmouth, to the north, south and to the west of the existing borefield, from which Water Corporation does not abstract water.
Water Corporation is licensed to take up to 1.032 gigalitres (1.032 billion litres) per annum from the Exmouth borefield, which relies on heavy episodic rainfall events in summer/autumn and winter rainfall for recharge.
Growth in annual demand at Exmouth has been low but steady since 2010 and is now approaching our abstraction licences. As annual demand may exceed the abstraction licence towards the end of this decade, source expansion will be required to provide an additional 0.5 gigalitres (500 million litres) per annum to meet future demand to 2050.
- Expansion or increased abstraction of the current borefield in the existing Exmouth Town and Exmouth Central groundwater areas – This was not a viable long-term option due to allocation and environmental impact.
Options being considered for further investigation to meet future demand include:
- Expansion into the groundwater subarea to the south – accessing up to 0.5GL/year of the 4GL/year currently available in DWER’s allocation plan for the Exmouth South Groundwater Sub Area.
- Develop a climate independent small-scale seawater desalination plant.
The infrastructure required when building a seawater desalination plant includes:
- An intake location where the seawater feeds into the treatment process. An intake that captures good quality clean seawater is important in reducing the complexity of the treatment process, its environmental footprint and improving the reliability of water supply. This can be achieved by an open seawater intake or subsurface water intake such as a coastal bore.
- A location to build a desalination plant to treat the seawater preferably in close proximity to the coast. A multi-criteria analysis has identified a number of site options and we are currently undertaking due diligence with stakeholders on potential locations.
- A brine outfall which disposes of the salty water following the treatment process into the ocean.
- Power supply, with the aim to utilise renewable power to align with Water Corporation’s objective to be net zero by 2035.
- Transfer infrastructure (pipes and pumps) to connect the treated drinking water to the scheme.
On average new sources typically take up to 8 years to deliver from investigation through to construction and commissioning, however Exmouth has complex ecological and cultural values that may impact this.
As we progress our investigations and engagement, we will be able to improve our estimate of a delivery timeframe.
Our next step is to connect with stakeholders and the community. We want to understand the social, environmental, cultural, and operational impacts of each option.
Our project team will host face to face drop in sessions in the new year so we can hear your thoughts and answer any questions you may have. We will be in touch soon with dates and times for these sessions.
If you’d like to provide feedback now, click here to have your say.
Carina Harris - Community Engagement Senior Advisor