Redbank Creek Dam

Redbank.jpg

Redbank Creek Dam was constructed as water storage infrastructure for the Mudgee Town Water Supply in 1899. The dam is a 16m high concrete arch dam with a crest length of 152m and a storage capacity of approximately 180 megalitres.

Following preliminary analyses and long-term observations by the Department of Public Works that the Dam was meeting satisfactory requirements, uncertainties were raised regarding the asset's concrete quality. It was concluded that the general and incremental flood hazard ratings for Redbank Creek Dam were considered a high level risk after a safety review of the dam was presented to Council in 1992. 

A stability analysis was completed and presented to Council by the Department of Land and Water Conservation in 1996, which examined the behaviour of the dam wall under static loadings at full supply level (FSL) and loading resulting from an inflow equivalent to a Probable Maximum Flood (PMF) event. The dam was also analysed for earthquake loadings. The report concluded that 'the dam is considered to be in an unsatisfactory state even for normal loadings and the dam does not satisfy accepted design criteria'.

The DLWC recommended that consideration be given to lowering the dam storage in the short term and decommissioning or strengthening the dam in the long term.

A detailed design for dam stabilisation works was approved by the Dams Safety Committee, the NSW Office of Water and the Department of Environment, Climate Change and Water.

Stabilisation works

Works carried out to date include:

  • Installation of a large diameter pipe through the base of the dam
  • Construction of downstream erosion protection
  • The dam is presently not capable of storing water except for short durations during large flood events (>20 years average recurrence interval) when inflows exceed the capacity of the pipe. Consequently, there is no longer a risk of a "sunny day" dam break event, as the dam does not normally store water.