After 28 years without a major flood, the Hawkesbury-Nepean Valley has experienced three major floods in the past three years. A proposal to raise the Warragamba Dam wall for flood mitigation in the Hawkesbury-Nepean is currently being assessed for development. However, fearing more damage from above-average rainfall predicted for this spring and summer, a community group has recently been advocating for urgent flood mitigation by changing the operation of the existing Warragamba Dam structure, including by lowering the amount of water stored in the dam.
In public discussion of using Warragamba Dam for flood mitigation, reference is sometimes made to legislation that prevents the dam being used in this way. But the specific legislation involved is rarely mentioned. This e-brief describes some of the legal and regulatory constraints that currently limit any flood mitigation uses of Warragamba Dam. These constraints include WaterNSW’s operating licence, various statutory instruments under the Water Management Act 2000, and WaterNSW’s risk of increased legal liability.