An issue arising with the January 2011 flood in Queensland was the effectiveness of a quasi-judicial Commission of Inquiry, as an investigative process, in determining improved flood mitigation works and control procedures for future flood events.

The findings of the Queensland Flood Commission of Inquiry [QFCI] are now the subject of both a further quasi-judicial inquiry about flooding at Grantham, and also a class action before the NSW Supreme Court about flooding in Brisbane. Both actions have been initiated by the victims of flooding who have found the support of independent technical experts critical of the technical findings by QFCI. For an Inquiry into a more recent flood at another dam also subject to overtopping, the Callide Dam, a quasi-judicial mechanism was not used. This Inquiry may have achieved better advice on particular technical issues.

This paper evaluates the strengths and possible deficiencies in the technical outputs from the quasi-judicial Commission of Inquiry, and the factors of technical expertise and legal process that may contribute to possible deficiencies.

Other formats for conducting inquiry into technical issues using combinations of technical expertise and legal process are outlined, and these are considered for their potential for achieving improved technical outcomes.

The paper concludes that independence of inquiry into technical issues is critical for optimum resolution of those technical issues, whatever format is adopted for the legal processes that assist an inquiry to other purposes. The choice of those legal processes, however, can assist technical expertise to achieve the best technical result.

Keywords: quasi-judicial inquiry, hydraulic modeling, risk management, dam operations, rainfall forecasts, flood control.