: News Article

Dam upgrade strategy endorsed

22/08/2003

NQ Water has endorsed a five-stage upgrade of the Ross River Dam recommended by a panel of internationally recognised engineering experts to bring the dam into line with new international standards.

The program, which will be staged over a period of five to eight years, involves lowering the spillway, fitting flow gates, constructing sand filters and supporting earthfill, augmenting wave-protecting rockwork and
associated works.

Any additional improvements will only be considered after detailed investigation, analysis and consultation with the State Government and Townsville and Thuringowa Councils before a commitment is made.

'The upgrade will ensure the dam is capable of withstanding a rainfall event that, on average, is estimated to occur only once in 400,000 years,' said NQ Water CEO Ken Diehm.

'As Ross River Dam is close to a large downstream population we are required by international standards to have a significantly higher level of safety than most other dams,' he added.

An initial estimate for the upgrade is $69.1 million but, depending on further detailed design, the final figure could be between $61 million and $90 million. Negotiations on funding the works are continuing between NQ Water and the State Government, which planned, designed and oversaw construction of the dam.

'Investigations into the 30-year-old dam's structure and operations have been very thorough, with more than two years work culminating in the experts' final report, which was considered by the NQ Water Board this week,' said Mr Diehm.

The main focus of the works will be the 7.5 kilometre long embankment, where a comprehensive sand filter system and overlays of stabilising fill will be placed on the downstream side. This will cope with normal dam seepage whilst ensuring the integrity of the dam is maintained.

''Water levels will need to be temporarily lowered to allow this work to be undertaken, with spillway modifications that are now under way being a first step,' Mr Diehm said.

'However, the dam's normal storage capabilities will be restored as quickly as possible once spillway gates are installed on top of the lowered spillway during the next stage of the upgrade. This work will occur in conjunction with the upgrading of the embankment.'

In planning the upgrades, consideration will also be given to potential for increasing the dam's storage capacity in the future.

Ross River Dam's dual purposes are flood mitigation and water supply, with NQ Water providing bulk supplies to Townsville and Thuringowa City Councils
and major industry.

In line with its policy of keeping the community informed about the dam upgrade works, NQ Water will stage public displays at Stockland Townsville on Thursday 4 September from 3.30pm to 7.30pm and the Willows Shoppingtown from 9am to noon on Saturday 6 September.

Digital images and broadcast video of RRD available

Contact
NQ Water Media Liaison: Robert Dark on 0417 623 156 for further information.

© 2004 NQ Water