Paradise Dam $700m disaster ripples spreading

It underpins a Queensland investment boom, but the Paradise Dam is riddled design and construction faults.

Bundaberg Mayor Jack Dempsey. Picture: John Wilson Story

Queensland’s Paradise Dam has a repair bill of up to $700m after major problems were found in its design and construction by a company then headed by the Palaszczuk government appointee who is now building the $5.4bn Cross River Rail in Brisbane.

Documents obtained by The Weekend Australian show the dam near Bundaberg, built by the Beattie Labor government for $200m through public-private joint venture vehicle Burnett Water and opened in 2005, is riddled with structural faults.

Graeme Newton, Cross River Rail Delivery Authority chief executive, was general manager and company secretary of Burnett Water during construction.

The 300,000 megalitre dam has underpinned an agricultural investment boom in the Bundaberg region — now the state’s largest farm employer. Hundreds of millions of dollars have been poured into macadamia, avocado and citrus plantations.

READ MORE: Paradise Dam’s missing documents | Dam safety exposed years ago

The Palaszczuk government and SunWater, the state-owned operator of the dam, began releasing 105,000ML of water in September because of safety concerns about the capacity of the 52m-tall dam wall to cope with a repeat of the 2013 floods.

The move almost halved the dam’s water levels to 42 per cent in the drought-declared region. It enabled repair work that will take until at least 2025 to complete.

Senior government sources said the debt-laden Palaszczuk government was considering permanently cutting the dam’s water storage level capacity to reduce the repair bill in a move that would undermine the future of the agriculture sector in the region.

Natural Resources Minister Anthony Lynham is understood to have been given two options: the estimated $700m cost of returning the facility to full capacity or cutting its capacity to 55 per cent at a cost of $180m.

Since the 10-week program to drop the dam’s water levels began on September 24 the government has refused to release any of the safety and engineering reports that led to the decision.

Paradise Dam at Coringa in Queensland. Picture: John Wilson

Premier Annastacia Palaszczuk said last week some of the material would be released once it was reviewed by US engineers and a plan for the dam was finalised.

A summary report of the initial two-year safety review, begun after the dam suffered damage in the 2013 floods and was completed in 2016, has been obtained by The Weekend Australian. It shows ­defects in the concrete layers of parts of the dam and that the spillway needed a major redesign.

Paradise Dam was among Australia’s first “roller compacted concrete” dams, which involves building the structure with layers of compacted, dry concrete separated by a thin membrane.

According to the report, engineers found the 300m concrete slab which sits under the spillway was washed away by the force of floodwater. The report warned that, even with major repairs after the one-in-200-year flood, major design problems had left the dam vulnerable, including to “undermining” of the concrete walls.

Several engineers contacted by The Weekend Australian said the report showed “serious design and construction problems”.

Ken Pearce, a 30-year veteran of dam engineering said there were a number of “major design problems” with Paradise Dam.

Mr Pearce said the Bundaberg community should make a formal complaint to the Board of Engineers over the dam’s design problems and push for an inquiry into the regulator’s 2005 approval to its construction: “There are serious problems with the design, particularly in the dissipater, which is critical to reducing the velocity of the water flow and ultimately to the safety of dam.”

According to the summary report, the 2013-16 safety review found the dam spillway was not able to maintain flow turbulence: “The primary spillway apron dissipater is considered insufficient to provide ‘controlled’ dissipation of energy and is likely to require a major redesign.”

The summary report said the critical “construction report” of Paradise Dam was among missing documents. It also warned there were “gaps in the geotechnical information available on the constructed dam foundations”.

Mr Newton was general manager of Burnett Water from October 2003 to June 2006, about five months before then premier Peter Beattie opened the dam. Burnett Water also included the consortium’s lead builder, Walter Construction Group, which went into administration before the dam was completed.

After leaving Burnett Water Mr Newton became chief executive of Queensland Water Infrastructure. In a statement, a spokesman for Cross River Rail said, as general manager of Burnett Water, Mr Newton did not have involvement in the design or construction of the dam.

“In relation to Paradise Dam, Graeme was responsible for community and stakeholder engagement and land acquisition,” the statement said.

“He was not responsible for the design or engineering.”

Dr Lynham refused to be drawn on the cost of repairing the dam: “Paradise Dam is safe today and tomorrow but SunWater’s ­advice is that action is needed to be taken immediately to ensure community safety.”

He said reducing the water level would allow work to improve the dam’s stability: “The decision to release water from Paradise Dam was not taken lightly with so much of the state in drought.”

Bundaberg mayor Jack Dempsey said the community had attracted investment based on its water security: “Water security is our biggest competitive advantage as a region. It’s part of why we’re the food bowl of Australia.

“It’s now critical that the government and the opposition guarantee they will restore the dam to its full capacity or greater.”