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Ewen Maddock Dam upgrade

In 2012-13, we commissioned an independent review of our 26 referable dams, which found improvements are needed at a number of our dams to meet the Queensland dam safety guidelines into the future.

We have prioritised a program of dam upgrades in a staged approach to give us time to scope, design and plan, while maintaining public safety, security of water supply and delivering best value for money.

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Home What We're Doing Ewen Maddock Dam upgrade

Ewen Maddock Dam is one of a number of dams in South East Queensland scheduled to be upgraded as part of our regular ongoing maintenance. The planned stage two upgrade work will include strengthening the existing embankment and increasing its floodwater capacity.

Ewen Maddock Dam safety upgrade

Stage two upgrade work is set to begin from August 2019. It will include strengthening the existing embankment and raising the dam wall to increase its floodwater capacity. Work is expected to take up to 18 months, subject to weather conditions and other unexpected delays.

Currently, the water level within the lake is at about 90 per cent of its Full Supply Level. During the upgrade we will need to lower the water level of the lake to about 60 per cent of the Full Supply Level. Lowering water levels is an industry accepted practice to manage dam safety and bank stability during upgrades. The lake will return to the current Full Supply Level following project completion and adequate rainfall.

For the safety of the public, all on-water recreation, access to the designated swimming area, access to the multi-use trails from Maddock Park, and the recreational use of Maddock Park will be closed for the duration of the upgrade work. Access to the multi-use trails from alternate locations will be maintained, where possible.

The upgrade work will not impact on water supply security which will be maintained by the SEQ Water Grid.



Ewen Maddock Dam was built in two stages in 1976 and 1983 across Addlington Creek, a tributary of the Mooloolah River. Located on the Sunshine Coast, Ewen Maddock Dam is part of the SEQ Water Grid.

In 2012, stage one upgrades at the dam involved the installation of pressure relief wells along the left abutment of the dam wall, and construction of a 1.5 metre weighting berm on the downstream toe area.

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    Ewen Maddock Dam to remain open over Spring

    One of the Sunshine Coast’s popular recreation areas, Ewen Maddock Dam, will remain open to the public during spring.

    The dam was originally earmarked for upgrade work to begin from August this year but has now been rescheduled.

    As a result, on-water recreation, including a designated swimming and beach area, will remain open until Seqwater finalises the new project timeline.

    Seqwater has recently modified the access points to the multi-use trails around the lake to ensure they can remain open during the upgrade and rejuvenated the adjacent wetlands area.

    Seqwater Chief Executive Officer Neil Brennan said unfortunately the tender process did not result in any viable tenders.

    “Dam upgrades are highly technical and complex projects. We are now conducting a post tender review to better understand the response of potential contractors before re-issuing a tender for the project. The new tender will reflect the review process,’’ Mr Brennan said.

    “The upgrade is part of Seqwater’s Dam Improvement Program designed to ensure SEQ dams can continue to perform safely into the future.

    “Dams are large-scale public infrastructures and maintaining their safety is paramount,” Mr Brennan said.

    “The upgrade of Ewen Maddock will increase the dam's resilience to extreme events and bring the dam in line with modern engineering design standards. The revised construction schedule will not increase any risks to dam safety.”

    To undertake the upgrade safely the lake’s water level will need to be lowered to about 60 per cent of its full supply level.

    During the upgrade, all on-water recreation, including the designated swimming and beach area, will be closed for the duration of the upgrade work. The closure will also extend to Maddock Park which will be required as a set down area for the project.

    Once the new timeline for the project is finalised Seqwater will host a community event at the newly renovated wetlands area to update the local community.

    Seqwater expects to issue a new tender before the end of the year. For more information about the Dam Improvement Program, visit www.seqwater.com.au/damimprovement.

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