2022 – Roles and responsibilities in the identification, management and emergency response to failure of small dams

Chris Nielsen, Rob Fowden, David Li, Tyson Leong-Cuzack Queensland Government

During the February to March 2022 flooding event in South East Queensland, the dam safety regulator was made aware of, and was required to advise on, six separate failures of small earth embankment dams.

Fortunately, in all instances these dams did not lead to life safety consequences, but their failures resulted in public disruptions causing road closures, local infrastructure damage and diverted stretched emergency response resources to manage.

There are significant risks associated with the failure of small earth embankment dams because they are often unknown to regulators and emergency responders, do not always meet good dam management practices, and there are several thousand of them scattered throughout rural areas.

Small dam embankments can be highly variable structures. Landowners or local contractors may construct them without using the best practices applied to larger, higher consequence dams. They may have unknown construction histories or be constructed to unknown or unchecked design standards. Also, proactive inspection and maintenance activities may not occur.

The nature of these risks differs from that of larger, higher consequence dams which are fewer in number, easily identified and are typically managed by appropriately skilled dam owners. As such, a different approach to their regulation and management is required.

The paper describes the strategy of the Queensland dam safety regulator to address this issue and improve dam safety outcomes, particularly during flood events. This includes; a program to identify those dams which pose a life safety risk and should be regulated to ensure appropriate minimum dam safety standards are applied; publication and promotion of relevant information for small dam owners on how to effectively manage and maintain their dams; providing advice to stakeholders during flooding events as to possible consequences associated with a failing dam, to inform potential evacuations and emergency response; and providing advice to stakeholders responsible for planning and management of water infrastructure and emergency response on how to identify and manage small dams within their jurisdiction.

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