Early drill tests start to raise wall of dam

04 July 2017

No access to Clarrie Hall Dam wall while drill rig operating

Contractors will begin drilling test holes at the wall of Clarrie Hall Dam next Tuesday, 11 July 2017, to confirm the strength of the underground rock and its suitability as a building material to raise the wall of Clarrie Hall Dam.

In December 2015, Council resolved to begin planning for and buying the land needed to raise the wall of the dam. Its decision followed an extensive assessment of the options available to increase the capacity of the Tweed District Water Supply. The early investigations and planning needed to raise the dam wall are progressing well.

“It’s still early days for raising the wall of the dam but we have to undertake these drilling tests now as the results are needed to design the higher wall,” said Manager Water and Wastewater Anthony Burnham.

Six test bore holes up to 30m deep will be drilled in the area of the proposed spillway for the raised dam and where the dam wall will be extended. A helicopter will be used to lift the drill rig around the test site.

“To ensure public safety, Council will lock the gate to the dam wall during the seven-week drill program,” said Mr Burnham.

Meanwhile, Council is working with the affected communities of Doon Doon and Commissioners Creek on options to continue to provide road access to the upper catchment once the dam wall is raised and McCabe’s Bridge is inundated.

As yet, Council has not selected a preferred option for providing continued road access but is undertaking further investigations into building a new higher bridge at the existing McCabe’s Bridge site and building an entirely new road into the area.

“We met with the affected community in late June and they asked us to do more work on both these options.

“When we know more about what each of these options entails and what each would cost, we will go back to the affected community and talk with them again.”