International Panel of Experts for Flood Studies list concerns with Inland Rail flood modelling

While the experts’ report found the “overall methodology” was considered appropriate, they also found there were “several concerns”.

The draft report of an international panel of flood experts has found several concerns with Australian Rail Track Corporation’s modelling of regional flooding.

While experts’ report found the “overall methodology” was considered appropriate, they found there were “several concerns” about its application, the sizing of drainage structures, the assessment of impacts, the level of detail provided in an earlier hydrology and flooding technical report to justify assumptions made, as well as the conclusions drawn in the same report.

The panel’s key finding with regard to ARTC’s Condamine flood plain hydrology analysis was in relation to flow rates.

“Due to the potential flow distribution issues identified when undertaking the (flood frequency analysis), there may be sections of the alignment for which waterway structures have been undersized.

That could in turn result in the need to redesign structures “across the alignment”, or “trigger current nonconformances in the current proposed design”, the report said.

The report also found ARTC had not included culverts at existing minor waterway crossings, especially those under the Gore Highway, which “could change flood results in frequent events”.

Australian Rail Track Corporation director of planning, communications and stakeholder relations Rebecca Pickering said the panel’s review “builds on and acknowledges the substantial amount of work undertaken by ARTC and other world-leading experts to construct Inland Rail in a way that is safe and suited to its environment”.

Ms Pickering said the panel found ARTC’s work “predominantly” met Australian guidelines and industry best practice and was clear the findings “are as expected for a significant infrastructure project … at this time in its development”.

“This is an excellent time to have had this input from the panel to assist in the refinement of the flood modelling,” she said.