‘I sought further advice from BoM on 1 November about the 2012-13 wet season,’ he said. ‘It’s clear from BoM’s latest advice, that this summer’s wet season is different from the strong La Nina conditions that persisted during the devastating Queensland floods of the 2010-11 wet season.’
The decision to not temporarily lower Wivenhoe or North Pine dam’s full supply levels was made after careful consideration of a number of factors. Following BoM’s presentation to the government cabinet in September, McArdle formally requested advice from DEWS which covered issues including seasonal weather forecasts, water supply security, dam operations, public safety, downstream impacts, public interest and the extent to which lowering the dams was likely to mitigate the impacts of a potential flood. It was supplemented by the BoM’s advice on 1 November.
Taking into account the difference between the current seasonal forecast, the 2010-11 forecasts, as well as drinking water security for south east Queensland, McArdle said he had decided not to lower Wivenhoe or North Pine dams at this time, but would continually review the decision and the levels of the dams.
‘Following recent legislative changes in Parliament, the process DEWS is required to follow to develop this advice has been significantly streamlined,’ he said. ‘The Queensland Floods Commission of Inquiry recommended that the regulatory framework, allowing the responsible minister to temporary alter a dam’s full supply level, be simplified.’
McArdle said under previous legislation, DEWS had to undertake a process up to a month long to update any previous advice to the minister. The new legislation allows DEWS, and the responsible minister, to be more responsive to new information. This includes updated seasonal forecasts and dam full supply levels which are monitored through the season.
The minister said it was important to recognise that Wivenhoe dam’s dedicated flood mitigation compartment remained completely empty and available for the summer wet season.
‘Wivenhoe dam was designed and constructed to operate as a dual purpose water supply and flood mitigation dam, and its dedicated water supply compartment is always less than half of the dam’s total capacity,’ he said. Its water supply compartment is currently at 96.5% per cent capacity, while North Pine dam’s is at 96.5% capacity.
