The proposal to raise the height of Warragamba Dam by 14 metres is unnecessary and environmentally damaging. The existing dam and auxiliary spillway provides the necessary dam safety. Installing new flood gates and improved flood monitoring would provide substantial flood mitigation at a saving of more than $700 million.
Some of the amount saved could be used for comprehensive flood management, including voluntary purchase and/or re-location of low lying houses and other structures; removing them from the path of all floods, not just smaller floods as is the case with the 14 metre raising.
There will be no protection against large floods (one in 500 average, and higher) even if the dam is enlarged.