The State Government will spend $690 million to raise the wall of Warragamba Dam by 14 metres.
NSW Premier Mike Baird has confirmed $58 million will be allocated to the first phase of the project in next week’s State Budget.
“The Hawkesbury-Nepean Valley has been identified as having the greatest flood risk in NSW, which poses a serious danger to life and property in western Sydney,” Mr Baird said.
“To help keep Western Sydney safe from floods we plan to raise the Warragamba Dam wall by 14 metres, which will offer significant extra protection for townships downstream, including Windsor, Richmond and parts of Penrith.
“This crucial investment is being made so we can reduce the risk to people, animals and property in the event of serious flooding.
“This investment underscores our commitment to making the right long term infrastructure decisions for NSW.”
Following detailed evaluation by an expert taskforce led by Infrastructure NSW, raising Warragamba Dam by 14 metres was identified as the most cost effective solution to significantly reduce risk to life and potential economic impacts in the valley.
The recommendation to the NSW Government to raise the dam wall was developed over four years, and required detailed, time consuming and cutting edge modelling of thousands of flooding, evacuation scenarios. This included modelling conducted by Data 61 from the CSIRO, which simulated over 12,000 road evacuation scenarios across different flood events to help determine the best flood mitigation solution.
The $58 million funding will be used to undertake detailed concept designs, environmental assessments and preparation of the full business case to raise the Warragamba Dam wall. The funding package will also be used to increase community flood risk awareness, create evacuation signage, improve flood forecasting and integrate the flood risk management with regional planning.
Raising the dam wall by 14 metres is expected to reduce potential economic impacts from flood risk by about 75 per cent on average.
Final approval of the project will come after the business case has been received, but the NSW Government is fully committed to alleviating the flood risks posed in the Hawkesbury-Nepean Valley.