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Flood study

Warragamba Flood Study - Hydrologic Modelling of The Hawkesbury/Nepean Catchment

As a result of increases in estimates of Probable Maximum Precipitation (PMP) over the past 40 years it is now apparent that Warragamba Dam is unsafe; even after the current remedial works are completed; In any flood above about 0.7 of the Probable Maximum Flood (PMF). The Water Board has determined that It will provide PMF protection to the dam and has identified a wide range of possible options to achieve this end. All of these options win Impact on the environment both at the dam site and, to varying degrees, in the valleys upstream and downstream of the dam.

The Water Board appointed Michell, McCotter and Associates to prepare an Environmental Impact Statement on the proposed protection works, Webb, McKeown and Associates were appointed as sub-consultants to carry out flood studies to determine the impact of various options on the flood regime downstream of the dam.

One aspect of Webb, McKeown's brief was to review work already carried out by the Board on hydrologlc modelling of the catchment. While the work was generally satisfactory, continuing developments, in particular the flood of May 1988, required that the callbratlon parameters derived by the Board be reconsidered.

This report presents a technical discussion of the recalibration process and suggests appropriate parameters for deriving design floods. For completeness, It includes a background summary of previous work on the dam hydrotogy and a review of the findings of those studies.

Additional Information

Field Value
Title Warragamba Flood Study - Hydrologic Modelling of The Hawkesbury/Nepean Catchment
Publication Date 1 June 1989
Themes Land and Resource Management
Spatial Extent
Map data © OpenStreetMap contributors
Council/LGA Wollondilly Shire Council
Author/ Prepared by Webb McKeown & Associates
Publish date 30 June 2020
Update date 30 June 2020
River Basin 212 - Hawkesbury
Approval State Approved
Submitted for approval 30 June 2020
Submitted by Akhil Sud
Approved 30 June 2020
Approved by dstazic
Identifier ec9abeb3-71da-4467-a2d0-83746ae26d51