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How we operate Canberra’s water sources

We are committed to providing a safe, secure and sustainable water supply to our region for generations to come. This is why our focus is always on ensuring long-term water security, both to support our growing population and to meet the challenges of climate change.

How we operate our water sources

We forecast storage levels across different climate scenarios to evaluate both operating cost and the risk of entering water restrictions. This means balancing water security and cost to ensure we can reliably supply drinking water to our community.

Canberra’s water is sourced from Corin Dam, Bendora Dam, Cotter Dam, Googong Dam and the Murrumbidgee River. Our guidelines encourage the use of water sources based on a balance of water security and operational efficiency.

The most inexpensive way for us to supply water is to exhaust the cheapest source before moving onto the next. The issue with this system is that water is lost from our other sources through spills (when excess water is released from a dam). This loss of water has a negative impact on our long-term water security.

We have updated our operating rules to mitigate this impact. Our teams will now aim to switch between water sources earlier. This will reduce the total water lost from over storage and increase our water resilience.

Why did we change our operating procedures?

The 2017-2020 drought triggered a review of our water security assessment. This resulted in updates to previous assumptions using newly available data, more modern processes and developments in science. 

When reviewing our positions, we consider local climate change projections using NARCliM data, government population projections and our own customer/environmental data. We use this information to project future consumption and water availability so we can plan to meet those needs.

Our 2022 water security assessments have shown a shift in conditions that means we are not as water secure as previously thought (based on prior forecasts). An improved understanding of rainfall runoff during drought periods is the most significant of these updates. This has resulted in two immediate responses:

  • We have changed the way we operate our water supply system. We now operate the system more securely which may result in increased supply from Cotter and Googong Dams by reducing spills. The trade off is these water sources cost more to operate. 
  • We have brought the triggers forward for transitioning from Permanent Water Conservation Measures (PWCM) to Temporary Water Restrictions (TWR).

The outcomes of our water security modelling have also brought forward investigations into our next future water source. In the short to medium term, significant investment will be required to progress water security and climate resilience investigations. This will include the consideration of new or augmented dams, additional river pumping, groundwater, demand management, recycled water and desalination.

The governance of water in the ACT

The amount of water we can supply is determined by the available supply in our storages and the legal right to take that water.

The ACT’s water resources are part of the Murray Darling Basin. The water resources of the Basin are governed under the Water Act 2007 (Cth) and Basin Plan 2012 (Cth). The ACT Government manages the amount of water used in the Canberra region under the Water Resources Act 2007 that supports the objectives of the Commonwealth legislation.

The ACT Water Resources Act 2007 sets out how the territory government manages water resources. The ACT and Region Catchment Coordination Group was established under this Act to provide a regional approach to water resource management. 

The ACT Water Strategy: Striking the Balance 2014–2044 sets out the government’s vision for water resource management. It details the ACT Government’s water-related policies and priorities.