Floodplain Management Study and Plan

North Sydney Council and the NSW Government, as part of the Floodplain Management Program, completed the North Sydney LGA Wide Flood Study 2017.

It began the process of identifying flood prone land in accordance with the NSW Government's Floodplain Development Manual.

 

Public Exhibition 1 June - 27 July 2022

The next stage of the study is drafting the floodplain risk management study and plan (FRMS&P) currently on Public Exhibition from 1 June to 27 July 2022.

Community consultation is on now and we encourage everyone to review the draft FRMS&P findings and FAQs - and have your say here:

https://yoursay.northsydney.nsw.gov.au/flood-study

 

 

Flood Study

A flood study is a comprehensive technical investigation of flood behaviour which defines the nature of flood risk in the LGA by providing information on the extent, level and velocity of floodwaters for a full range of flood magnitudes.

A FRMS&P draws on the results of the flood study to identify, assess and compare various flood risk management options and opportunities aimed at improving the existing flood situation in the LGA. It provides information and tools to allow considered assessment of flood impacts, the management options, plus provides a strategic plan for implementation.

Management options are typically categorised as property modification measures, response modification measures, and flood modification measures.

 

floodplain_flowchart.jpg
 
 
2. Flood Study - complete. Adopted by Council in 2017.

3/4. Floodplain Risk Management Study & Plan - on Public Exhibition to 27 July 2022.

 
 

 

What is Flooding?

Flooding is often associated with inundation from large rivers; however, there are other flood mechanisms that can cause inundation. The North Sydney LGA is primarily affected by two types of flooding; overland flow flooding and mainstream flooding.

Overland flow flooding occurs as rainfall runoff moves toward downstream waterways. Mainstream flooding occurs when runoff from streets and drains flow into waterways causing them to rise and inundate areas that are usually dry.
grchydro_overlandflow_5.gif grchydro_creekflooding_5.gif

 

A FRMS&P provides key information for Council, the SES and the community for effectively managing and mitigating flood risk.

For Council, FRMS&P’s are primarily a planning tool for future development in the LGA and implementing flood mitigation measures for existing development areas. Examples of applications for Council are listed below:

  • examination of Council’s local flood risk management policies, strategies and planning instruments; and
  • identification and assessment of floodplain risk management measures for existing development areas aimed at reducing social, environmental and economic loss of flooding on development and the community.

Information from the FRMS&P will assist the SES in its evacuation and logistics planning. The outcomes of the study will provide the SES with:

  • a clear description of flood behaviour in the study area for a full range of flood events;
  • a description of flood warning times for the LGA; and
  • identification of critical evacuation issues in the LGA such as locations where road access is cut and the warning time before road access is cut.

If a property is identified as being located within the Flood Planning Levels, this means that flood-related development controls may apply for future development applications.

The Flood study is available to download here:

Flood Study (39MB)

Figures 18 to 23 - Peak Flood depth and contours (192MB)

 

The Draft Floodplain Risk Management Study and Plan is available to download here (plus FAQ):

FRMS&P draft document (62MB)

FAQ - frequently asked questions (579KB)

 

In June 2022 we hosted an online community information session with GRC Hydro consultants. View the video below and the Flood Study session - questions and answers (147KB):

 

 

Flood Insurance Fact Sheets

Insurance fact sheets - www.floods.asn.au/site/flood-insurance-fact-sheets

 

Further Information

Should you have any queries or require further information please do not hesitate to contact Jim Moore, Engineering Project Manager, on 9936 8100 or email floodstudy@northsydney.nsw.gov.au