Orange City Council dam safety risk assessments

Client: Orange City Council
Location: New South Wales, Australia
Date: 2023-24

Conducting dam safety risk assessments to help a local council prioritise safety improvements

Description

Orange City Council owns 4 large dams: Gosling Creek Dam, Suma Park Dam, Spring Creek Dam and Lake Canobolas Dam. These were constructed from the 1890s to the 1960s. The largest of the dams is Suma Park Dam, which is a 32 m high concrete-arched dam with an earthfill embankment and concrete fuse gates.

Orange City Council needed to assess risks across its portfolio to ensure compliance with Dam Safety New South Wales regulations and so that the council could prioritise upgrades where necessary.

Solution

Entura was engaged by Orange City Council to inspect the 4 dams and facilitate a risk assessment workshop. Entura collaborated with the council, which allowed us to align with the council’s needs while sharing important dam safety insights.

We conducted detailed condition assessments and screening for critical failure scenarios, as well as structural, hydrological and geotechnical assessments and quantifying risks.

Some of the complex considerations involved in this project included recreational dam users, aging infrastructure, incorporating findings of recent geotechnical investigations, and understanding risks associated with fuse gates.

Entura developed F-N plots to visualise risk levels and ensure compliance with the Australian National Committee on Large Dams’ (ANCOLD) guidelines, culminating in the creation of a prioritised action plan, including upgrade options and cost estimates to be provided to the council.

Our technical expertise ensured precise analysis, enabling us to address data gaps efficiently and suggest solutions to meet safety and regulatory goals.

Outcome

Entura provided Orange City Council with a clear understanding of the risk profile of its dams and compliance with Dam Safety NSW and ANCOLD guidelines, a prioritised program of work to meet regulatory requirements, and key regulatory metrics including the ‘Cost to Save a Statistical Life’, F-N plots and ‘As Low as Reasonably Possible’ (ALARP) assessments for informed capital works planning.

Our work has supported the council to manage dam safety proactively, with clear insights into risk priorities and regulatory compliance.