Powells Creek Flood Study Title
Consultant
Branches
Date
Comment
No.
32-36 Burlington Road, Homebush
B Lysenko
Strathfield Ck
February 1994
Determined design flood levels.
9
Lower Parramatta River Flood Study
Willing & Partners
Powells Creek to approximately Pomeroy Street
February 1986
Determined design flood levels.
10
Powells Creek at Underwood Street Site Flood Study
Tierney & Partners
Powells Creek at Pomeroy Street
November 1993
Determined design flood levels.
11
The references listed in Table 1 are of little value in the current study as they provide little historical data, and the results cannot be easily compared. The 2016 Powells Creek Revised Flood Study (Reference 2), however, is a comparable study to the current one and extensive use has been made of the data and results which were originally contained in the prior 1998 Powells Creek Flood Study (Reference 1). The City of Canada Bay commissioned Jacobs to undertake the 2015 Concord West Precinct Master Plan Flood Study (Reference 3), however this only covered the City of Canada Bay LGA.
2.2.1.
1998 Powells Creek Flood Study (Reference 1)
The 1998 Powells Creek Flood Study was undertaken under the NSW Government's Floodplain Management Program and used best practice techniques available at the time. A field survey was undertaken to provide approximately 100 cross sections of the creek channel as well as to collect historical flood height data. Some of the cross-section data have been used in the current study and the historical flood height data is provided in Section 2.10. A comprehensive data search was undertaken including: • a review of previous studies. • interviews with residents. • discussions with Council Officers. • contact with SWC, the then Roads & Traffic Authority, the then State Rail Authority, the then Department of Land & Water Conservation and the UNSW. • review of aerial photographs. • provision of a questionnaire and review of all previous questionnaires. • obtaining height and rainfall data from the stream and rainfall gauges operated by the UNSW and SWC. An ILSAX hydrologic model of the entire Powells and Saleyards Creeks catchment was constructed using ILSAX files from some of the studies listed in Table 1. Inflows from ILSAX were then input into the 1D HEC-RAS hydraulic model which determined flood levels and velocities. Flood extents were not defined; however, this was subsequently undertaken using the peak levels and ALS for the Strathfield LGA. The ILSAX model was calibrated to the events of 3rd February, 7th February, 10th February, 17th February and 18th March 1990 using rainfall from two pluviometers at St Sabina College and at the Elva Street gauge. Calibration to the Elva Street gauge for the January 1996 event could not be undertaken as the gauge malfunctioned. The results are summarised in the 2016 Powells WMAwater C:\Users\dewar\Desktop\Work\PowellsCkCanadaBay120079\Admin\Report\PowellsCk_FS_CanadaBay.docx:21 April 2022
7
