Raising the dam comes at enormous cost, will not mitigate all floods and in being an incomplete solution put even larger numbers of people and more property at risk than is currently the case. A better solution would be to:
- Use the existing dam and rainfall preduction tools effectively to mitigate floods.
- Put in place effective and safe planning frameworks around flood plains.
- Recognise the flood plains for what they are and utilise their unique attributes in providing high quality recreation and food supply resources near Sydney.
- Use resources to build infrastructure enabling safe evacuation, enable early warning, properly risk assess current danger to life and property and manage specific risks.
Flood mitigation soley relying on dams is susceptible to:
- encouragement of settlement in areas that are still subject to floods that exceed the maximum design flood.
- are an exceptionally high cost solution in protecting against some floods, not all floods.
- reduced effectiveness over time due to the accumulation of sediment in river beds and reservoirs.
- remove the benefits of natural flooding to downstream ecosystems.
SMH on Warragamba Dam flood mitigation - historical maximum flood of 19.3m would only be reduced by 4m.