The Hawkesbury-Nepean River Flood Study (May 2024) identifies areas in the Valley affected by flooding from the Hawkesbury-Nepean River (including backwater flooding up tributaries) and assesses the potential impacts of climate change on flooding.

The study area falls mainly within the Penrith, Hawkesbury, Blacktown and The Hills Local Government Areas but also includes parts of Wollondilly, Liverpool, Hornsby and Central Coast. It accounts for flows from the entire 21,400km2 Hawkesbury-Nepean catchment and provides detailed flood information for the 190km length of the Hawkesbury-Nepean River from Bents Basin near Wallacia through to Brooklyn.

Councils and other agencies reviewed the draft study (2023), and 2 independent reviews were also conducted. All comments were carefully considered prior to finalisation.

The Study, including all technical data and map books, is considered the most up-to-date and reliable source of flood information for the Hawkesbury-Nepean River and should be used to inform all flood-related decision making from June 2024.