The inquiry, which the Queensland Government announced last week, will be the second launched into the Grantham flood that occurred in January 2011.
The first inquiry was held as part of a wider investigation into the Queensland flood disaster of 2010 and 2011, which affected 70 per cent of the state. The Queensland Floods Commission of Inquiry released its final report in March 2012.
Queensland Premier Annastacia Palaszczuk said Grantham residents had called for an additional investigation that focused specifically on the flooding of Lockyer Creek between Helidon and Grantham. This was in light of a report commissioned by national newspaper The Australian earlier this year that called the findings of the original inquiry into question.
“A DHI consultant report published in The Australian newspaper has suggested several inconsistencies,” Palaszczuk explained. “The report has found that a section of embankment that collapsed at the Grantham quarry was 260m long – not 55m, as initially reported by the Queensland Floods Commission of Inquiry. This DHI report has found there were also multiple breaches of the quarry wall rather than just a single breach.”
The Grantham quarry is currently owned by Boral but at the time of the floods it was operated by Toowoomba-based construction materials business Wagners.
Wagners managing director Denis Wagner said he disagreed with DHI’s report because it contained “very little engineering fact”. He added that he was satisfied with the findings of the original investigation, which concluded that “none of the earthworks associated with the quarry caused or contributed to the flooding of Grantham on 10 January, 2011”.
This conclusion was based on evidence presented by Sinclair Knight Merz senior hydrologist Dr Phillip Jordan, who suggested the quarry may even have helped lessen the flood’s impact. Jordan said the quarry had reduced water levels by up to 10cm and delayed the water’s arrival in the town of Grantham by about 10 minutes.
Wagner stated that his business would co-operate and assist the inquiry in any way it could.
The five key terms of reference for the inquiry are:
• The impacts of man-made and natural features of the landscape which could have altered or contributed to the flooding.
• Whether the existence or breach of the Grantham quarry caused or contributed to the flooding.
• Whether the quarry had a material impact on the damage caused.
• Whether the breach of the quarry had implications for the evacuation of the town.
• How these matters were initially investigated and how eyewitness accounts were dealt with in the aftermath.
The inquiry will run from 11 May until 31 August, 2015.
Queensland quarry lessened flood: expert