Responsible Agency: Seqwater
Proposal Stage of Development: Detailed Business Case Underway
Building Queensland Role: Assisting with Detailed Business Case
Planned Stage End Date: Q3 2017
Estimated Cost of Delivery: $80 million*
Date of Publication: June 2017 (for period 4 December 2016 – 3 June 2017)


Lake Macdonald Dam on Six Mile Creek on the Sunshine Coast requires an upgrade to meet modern standards and the performance requirements of the Queensland dam safety regulations into the future.

The assessment of Lake Macdonald considered:

  • population growth downstream of the dam
  • advances in dam design and development of consistent methodologies for assessment of dam safety
  • the latest estimates of extreme rainfall
  • data from recent major weather events and updated modelling
  • improved understanding of earthquake probabilities and loads.


The proposal is investigating options to reduce dam safety risks by improving the spillway discharge capacity and earthquake stability, while maintaining water supply security.

Studies have considered a range of options including decommissioning of the dam, retrofit of strengthening works and new build options.


Complete Detailed Business Case

* Nominal Cost in Australian Dollars 2016, estimate provided by Responsible Agency.