Flooding

flood risk management

Steep terrain and ridge-top development have led to the major flood risk within Ku-ring-gai resulting from flash flooding along headwater streams and drainage depressions. Ku-ring-gai’s flood risk management program is based on the requirements of the NSW Floodplain Development Manual and Flood Prone Land Policy.

The primary objective is to allow the appropriate use of flood prone land while reducing the impact of flooding and flood liability on individual owners and occupiers of flood prone property and to reduce the private and public losses resulting from floods.

Current studies

Lane Cove Southern Catchments Flood Study

Ku-ring-gai Council has received funding for the Lane Cove Southern Catchments Flood Study through the NSW Government Floodplain Management grants 2022-2023.

The study area includes Sugarbag Creek, Little Blue Gum Creek and Blue Gum Creek, that all flow to Lane Cove River south of the Pacific Highway.

These waterways are in the suburbs of Killara, Lindfield and Roseville.

We are asking the public for information such as photos and observations of flooding behaviour, please complete a short survey before 19 June 2024. If you would like a printed copy of the survey mailed to you please contact floodriskmanagement@krg.nsw.gov.au with your address.

For more information about this study please read the community newsletter(PDF, 10MB).

Lane Cove Northern Catchments Flood Study

Ku-ring-gai Council has recently received funding for the Lane Cove Northern Catchments flood Study through the NSW Government Floodplain Management Program grants 2020-21.

The study area includes Coups Creek, Water Dragon Creek, Peppermint Creek, Avondale Creek and Quarry Creek as well as smaller tributaries of Lane Cove River.

These waterways are in the suburbs of Wahroonga, Warrawee, Turramurra, South Turramurra, Pymble and West Pymble.

For more information about this study please read the community newsletter(PDF, 2MB).

Middle Harbour Northern Catchments Flood Study

Council has received funding for the Middle Harbour Northern Catchments flood study through the NSW Government Floodplain Management Program grants 2019-20. The catchment area includes Middle Harbour Creek (and associated tributaries) in St Ives and Rocky Creek (including Stoney Creek and High Ridge Creek) in Gordon/East Killara which flow into Middle Harbour.

The draft report has been completed and was on public exhibition from October-November 2023. 

The final report is expected in 2024, following consideration of submissions.

For more information about this study please read the community newsletter(PDF, 2MB) and exhibition documents.

Flood Risk Management Committee

This advisory group is the first formal step in the floodplain risk management process.

They act as both a focus and forum for the discussion of technical, social, environmental, cultural and economic issues during the development of flood studies and flood risk management plans. Its membership consists of representatives from Council (elected representatives and staff), relevant government agencies including Office of Environment and Heritage, National Parks and Wildlife Service NSW, Sydney Water and the State Emergency Service, as well as representatives from the local community.

Council’s Floodplain Risk Management Committee (established in 2015) is currently overseeing implementation of the floodplain risk management process for sub-catchments in the LGA, in partnership with the NSW Office of Environment and Heritage.

There are currently 6 community representatives on the committee in addition to Chair Deputy Mayor Barbara Ward and  Deputy Chair Councillor Greg Taylor.  Community representatives for each term are nominated following the Council elections.

Meetings of the Committee are held as required. Meeting agendas and minutes are published on Council's website.

Please read the Terms of Reference(PDF, 229KB).

Completed studies, reports and mapping

Blackbutt Flood Risk Management Study and Plan

Blackbutt Creek Flood Risk Management Study and Plan was completed in August 2016.

This report builds on the findings from the Blackbutt Creek Flood Study (2014) and outlines measures to mitigate flooding including land use planning, community awareness, flood warning and infrastructure changes and upgrades.

Blackbutt Creek Flood Risk Management Study Report(PDF, 445KB)

Preliminary Floodplain Management Measures(PDF, 3MB)

Floodplain Risk Management Plan and References(PDF, 50KB)

Appendix A Locality Plan, Pipe Network and Vulnerable Locations

Appendix A Locality Plan(PDF, 2MB)

Appendix A Pipe Network Capacity(PDF, 4MB)

Appendix A Vulnerable Locations(PDF, 2MB)

Appendix A Emergency Response Classification Maps

Appendix A AEP Emergency Response Classification Maps(PDF, 7MB)

Appendix A PMF Emergency Response Classification(PDF, 4MB)

Appendix A Flood Risk Precinct 20% & 5% AEP

Appendix A Flood Risk Precinct Maps 20% AEP Proposed True Hazard Classification(PDF, 5MB)

Appendix A Flood Risk Precinct Maps 5% AEP Proposed True Hazard Classification(PDF, 5MB)

Appendix A Flood Risk Precinct 1% and AEP

Appendix A Flood Risk Precinct Map 1% AEP Proposed True Hazard Classification(PDF, 5MB)

Appendix A Flood Risk Precinct Map PMF Proposed True Hazard Classification(PDF, 5MB)

Appendix A Flood Modification Options

Appendix A Flood Modification Mitigation Options(PDF, 5MB)

Appendix B Assessment of Changes in the Blackbutt Creek Catchment

Appendix B Assessment of Changes in the Blackbutt Creek Catchment(PDF, 3MB)

Appendix C Draft Flood Planning Matrix – Appendix D Sensitivity Memorandum

Appendix C Draft Flood Planning Matrix(PDF, 39KB)

Appendix D Sensitivity Memorandum(PDF, 189KB)

Appendix D Sensitivity Memorandum Map(PDF, 5MB)

Blackbutt Creek Flood Study

The Blackbutt Creek Flood Study is the first of a series of detailed flood studies to be undertaken in Ku-ring-gai. This study used historical information, landscape survey, stormwater pipe data and computer modelling techniques to indicate areas likely to be impacted by flooding. The original Flood Study was completed in December 2014.

Final Report Blackbutt Creek Flood Study, Appendix A- B Community Consultation Survey and Summary

Final Report Blackbutt Creek Flood Study – Appendix A – B Community Consultation Survey and Summary(PDF, 4MB)

Appendix C- Flood Depth Mapping

Appendix C – Flood Depth Mapping(PDF, 10MB)

Appendix D- Flood Level Mapping, Appendix E- Summary of Peak Flows, Appendix F- Hydraulic Categories Mapping

Appendix D Flood Level Mapping – Appendix E Summary of Peak Flows – Appendix F Hydraulic Categories Mapping(PDF, 9MB)

Appendix G- Provisional Flood Hazard Mapping

Appendix G Provisional Flood Hazard Mapping(PDF, 6MB)

Appendix H - Flood Planning Area Mapping, Appendix I- Preliminary Flood Emergency Response Classification of Communities, Appendix J- Climate Change Impact Mapping

Appendix H Flood Planning Area Mapping – Appendix I Preliminary Flood Emergency Response Classification of Communities – Appendix J Climate Change Impact Mapping(PDF, 5MB)

Lovers Jump Creek Flood Study Review Report

The Lovers Jump Creek Flood Study Review Report (2018) was adopted by Council in November 2018.

Lovers Jump Creek Flood Study Review Report 2018

Lovers Jump Creek Flood Study, November 2018

Final Report(PDF, 2MB)

Appendix A- Historic Rainfall Data, Appendix B- Community Consultation, Appendix C- Questionnaire Responses and Verification of Model Flood Behaviour, Appendix D- Flood Depth Mapping

Appendix A - D(PDF, 5MB)

Appendix E- Flood Level Mapping, Appendix F- Summary of Peak Flows

 Appendix E - F(PDF, 3MB)

Appendix G- Hydraulic Categories Mapping, Appendix H- Provisional Flood Hazard Mapping, Appendix I- Flood Planning Area Mapping, Appendix J- Preliminary Flood Emergency Response Classification of Communities

Appendix G - J(PDF, 6MB)

Appendix K- Climate Change Impact Mapping, Appendix L- Impacts of ARR 2016 and At-Site Design Rainfall on Flood Behaviour

Appendix K - L(PDF, 3MB)

Lovers Jump Creek Flood Risk Management Study and Plan

Middle Harbour Southern Catchments Flood Study

The Middle Harbour Southern Catchments Flood Study area consists of five catchments. These include Echo Point and Moores Creek in Roseville, “Wellington Road” and Gordon Creek in Lindfield and “Northern and Southern Creeks” in Killara, all flowing into Middle Harbour.

Final Report - Middle Harbour Southern Catchments Flood Study(PDF, 18MB)

Annex A - Rainfall gauges

Annex A - Rainfall gauges(PDF, 186KB)

Annex B - Detailed Survey Plans

Annex B - Detailed Survey Plans(PDF, 8MB)

Annex C - Community consultation materials

Annex C - Community consultation materials(PDF, 458KB)

Annex D - Selected community consultation responses

Annex D - Selected community consultation responses(PDF, 400KB)

Annex E - AR&R datahub results

Annex E - AR&R datahub results(PDF, 250KB)

Annex F - ARF results

Annex F - ARF results(PDF, 129KB)

Annex G - ARR blockage assessment form

Annex G - ARR blockage assessment form(PDF, 288KB)

Annex H - Design flood results

Annex H - Design flood results - pages 1-10 - Peak flood depth(PDF, 82MB)

Annex H - Design flood results - pages 11-18 - Peak flood level(PDF, 82MB)

Annex H - Design flood results - pages 19-26 - Peak flood velocity(PDF, 85MB)

Annex H - Design flood results - pages 27-33 - Provisional hydraulic hazard, hydraulic categorisation and stormwater system capacity(PDF, 72MB)

More information

If you have any questions please email floodriskmanagement@krg.nsw.gov.au.