Eastern Creek is located in Western Sydney and drains a catchment area of 118 km2 to South Creek which, in turn, drains into the Hawkesbury River near Windsor. Eastern Creek drains approximately one half of the Blacktown Local Government Area.

To help manage the flood risk across the catchment, the ‘Blacktown Floodplain Management Study’ (Bewsher Consulting, 1996) was prepared. However, since this report was prepared, significant development has occurred across the catchment. This has likely altered rainfall/runoff characteristics across the catchment. As a result, the information presented in this original report is no longer considered to provide a reliable representation of the flood risk across the Eastern Creek catchment. In addition, significant areas of the catchment are earmarked for future development, which will further change flood behaviour. This includes the North West Growth Centre and Western Sydney Employment Area.

In order to fulfil their obligations under the NSW Government’s ‘Floodplain Development Manual’ (2005), Blacktown City Council proposes to update the previous Floodplain Risk Management Plan to reflect contemporary and potential future conditions.

This study forms the hydraulic assessment for the Eastern Creek catchment and comprises the second stage in the development of the Floodplain Planning Study for Eastern Creek. It takes the flow information that was generated as part of the stage 1 hydrologic assessment and defines how these flows would be distributed across the catchment. It provides information on flood levels, depths and flow velocities for a range of design floods. It also provides estimates of the variation in flood hazard and hydraulic categories across the catchment and provides an assessment of the potential impacts of climate change on existing flood behaviour.