An integrated approach
The concept design was prepared at the same time as environmental studies to integrate environmental fieldwork findings and to inform the Environmental Impact Statement.
Key activities focused on investigating the condition of the existing dam and its foundations, analysing the raised dam and defining the proposed design (which does not include any additional storage capacity).
Geotechnical drilling at Warragamba Dam Cored samples of rock from the foundations
Testing the strength of the rock samples
In order to inform the design, key activites were undertaken:
- review of all existing dam data – so the current dam is well understood
- geological mapping, drilling and testing – to assess the rock foundation conditions
- existing concrete drilling and testing – to understand the strength of the dam concrete
- concrete mix design and laboratory trials – to determine which concrete mix is best
- hydrology and seismic assessments and advanced computer structural analysis – to determine the floods and earthquake loads that the dam must tolerate safely
- advanced computer hydraulic analysis and a scale physical hydraulic model – to assess the ability of the raised dam spillways to safely discharge floodwaters
- detailing of the other civil, mechanical and electrical aspects of the design – important supplementary design elements
- determined the raised dam preliminary operating procedures – to define how the raised dam would be operated to capture the peak of an extreme flood and control its release gradually to reduce velocity and depth of flooding downstream of the dam
- design of an environmental flow structure – to provide controlled flows to improve river health.
Physical hydraulic model under construction Physical hydraulic model being water tested
2D structural analysis of the raised dam 3D structural analysis of the raised dam
The proposed Warragamba Dam Raising is complicated by the need to maintain operations safely throughout construction.
To ensure the design is fit for purpose and robust, WaterNSW have engaged a highly experienced international team of engineers who are leading specialists in their fields. The team includes:
- dam engineers
- structural, civil, mechanical and electrical engineers
WaterNSW chose practice leaders from Australia, America and New Zealand for their skills in designing major dams.
Large dams in NSW must be designed and managed to comply with the Dams Safety NSW Guidelines. The guidelines align with Australian National Committee on Large Dam guidelines which, in turn, are aligned with International Committee on Large Dam guidelines.
3D geometry model of the raised Warragamba Dam