Urban floodplain land-use - acceptable risk? : A case study of flood risk perception on the Guragunbah (Carrara-Merrimac) floodplain, Gold Coast

摘要

In Australia, the developments of hazard-specific legislation, policy and guidelines aims to minimise community exposure to the adverse effects of natural hazards. This occurs under policies of ecologically sustainable development land-use planning processes, which must also now involve the assessment of hazard-risk. However the development occurring in potentially hazardous environments, for example urban floodplains susceptible to flooding, continues to occur as a result of contemporary land-use planning and risk management processes. Why is this an outcome of past and present risk management and land-use planning processes? This thesis finds that a significant factor contributing to this outcome is the discrepancy between the perception and management of risk, particularly acceptable risk, by stakeholders (Local Government, the development industry, risk managers and floodplain occupants). The research is based on an Australian example of an urban floodplain currently under considerable development pressure, but at risk from flooding – Guragunbah (Carrara Merrimac Floodplain) and surrounding suburbs within the Nerang River catchment on the Gold Coast. A case study methodology was adopted, involving a combination of survey data and secondary documents.ududA basis for the thesis was the modelling of the actual risk decision-making processes operating within the case study Local Government, and the comparison between actual observed process and the theoretical framework outlined by the existing hazard risk management and land-use planning policy, guidelines and legislation. This enabled the identification of key stakeholders and their roles within the risk management and land-use planning processes operating within the case study area.ududThe scope of the results of this thesis indicate that a large proportion of stakeholders external to the Local Government (such as residents and some members of the development industry) do not understand the risks of flooding represented by the standards formally adopted by local government (1-in-100 year flood, for example) and as a result, misinterpret their levels of flood risk exposure. Importantly, the results also indicate that contrasts exist in the flood risks considered to be ‘acceptable’ by the stakeholders, particularly when the potential consequences associated with events are described or illustrated in ‘non-technical’ terms. The extent to which the formal standards are misinterpreted suggests that many stakeholders may potentially be exposed to risks greater than they consider to be ‘acceptable’, but they are assuming that the Local Government (in particular) is setting risk standards that are acceptable to them. ududThe thesis questions the true ‘acceptability’ of the formal standards being adopted through floodplain management policy at the Local, State and Federal levels of Government and identifies management opportunities and constraints in addressing the issue. Obstacles to management change include resource availability, lack of political will and stakeholder consultation. Opportunities for management change include modifying: the approach adopted by Local Governments when constructing planning schemes; the existing planning standards and decisions associated with permissible individual land-use; the mitigation of existing flood risks and exposure; and the communication of flood risk information. In the ‘real-world’ Local Government context, as illustrated by this case study, the issue may be practically addressed by modifying the standards and processes followed to establish acceptable risk.