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Flood study

Lake Illawarra, Mt Warrigal and Oak Flats Flood Study

The Lake Illawarra, Mt Warrigal and Oak Flats Flood Study has been prepared for Shellharbour City Council (Council) to define the existing flood behaviour in the Lake Illawarra, Mt Warrigal and Oak Flats catchment. The flood study, with guidance from Council’s Floodplain Management Committee, will establish the basis for subsequent floodplain risk management activities. The study is designed to meet the objectives of the NSW State Government’s Flood Prone Land Policy. This project has been conducted under the State assisted Floodplain Management Program and received State financial support.

The primary objective of this flood study is to define the flood behaviour under historical, existing and future conditions (incorporating potential impacts of climate change) in the Lake Illawarra, Mt Warrigal and Oak Flats Catchment for a full range of design flood events. The study provides information on flood levels, depths, velocities, flows, hydraulic categories and provisional hazard categories. Specifically, the study incorporates:

  • Compilation and review of existing information pertinent to the study and acquisition of additional data including survey as required;
  • Community consultation and participation program to identify local flooding concerns, collect information on historical flood behaviour, advise on the outcomes of the flood study and flood behaviour predictions, and engage the community in the on-going floodplain management process;
  • Development and calibration of appropriate hydrologic and hydraulic models;
  • Determination of design flood conditions for a range of design events - including the 20% AEP (~5 year ARI)1, 10% AEP (10 year ARI), 5% AEP (20 year ARI), 2% AEP (50 year ARI), 1% AEP (100 year ARI), 0.5% AEP (200 year ARI) and the Probable Maximum Flood (PMF); and
  • Examination of potential impact of climate change using the latest guidelines.

Additional Information

Field Value
Title Lake Illawarra, Mt Warrigal and Oak Flats Flood Study
Publication Date 23 December 2019
Themes Land and Resource Management
Spatial Extent
Map data © OpenStreetMap contributors
Council/LGA Shellharbour City Council
Author/ Prepared by BMT WBM
Publish date 10 June 2020
Update date 10 June 2020
River Basin 214 - Wollongong
Approval State Approved
Submitted for approval 10 June 2020
Submitted by Akhil Sud
Approved 11 June 2020
Approved by dstazic
Identifier 48670370-ee64-41fb-b5df-b4e9d7d04ed7