Flooding and Stormwater

One of the special things about living in Warringah is its natural bushland, geography and waterways. Some of these waterways are naturally prone to flooding.

• Flooding
• Narrabeen and Manly Lagoon Catchments Flood Studies
• SES
• Bureau of Meteorology
• Stormwater
• Northern Beaches Stormwater Management Plan
• Dee Why Flood Management

Flooding

Warringah Council uses flooding predictions for the one-in-100 year storm to identify flood affected land and plan for future development. The State Government has developed the NSW Flood Policy which helps Council manage flood affected land, provides financial assistance to help alleviate some existing problems and provides specialist technical advice.

Council’s key planning document is the Warringah Local Environment Plan (2000) and under this plan, new development on flood affected land must meet three requirements:

• Floor levels must be built 500mm above the predicted one-in-100 year flood level
• Development must not restrict the flow of floodwaters or take away area that could store floodwaters
• Development must be constructed from flood compatible materials.

The intention of the NSW Flood Policy is not to block development in the floodplain but ensure the development is protected from floodwaters and built in a way that doesn’t make flooding worse for other people in the floodplain.

• FloodSafe Warringah Brochure (4MB)
• Flooding - Frequently Asked Questions

Manly and Narrabeen Lagoon Flood Studies

Warringah Council, in partnership with Manly and Pittwater Councils, is undertaking detailed flood studies of the Manly and Narrabeen Lagoon catchments to improve our understanding of flood behaviour and identify problem areas.

The aim of the studies is to:

• define existing flood behaviour
• help identify flooding problem areas in Manly and Narrabeen Lagoon catchments
• assess the impacts of climate change

The studies will also identify the impact sea level rise and rainfall intensity will have on the flood behaviour of the catchments. 

The studies will help improve council’s planning and management, such as setting flood levels for development control and improving flood emergency responses.

You can help by posting information and photos of flooding or drainage problems on the websites set up specifically for the Narrabeen Lagoon and Manly Lagoon flood studies.

Each Flood Study has a specific project webpage:

• Manly Lagoon Flood Study
• Narrabeen Lagoon Flood Study

For information on whether you are affected by flooding call Natural Environment Unit on 9942 2111. 

NSW State Emergency Services (SES)

NSW State Emergency Service is the combat agency responsible for flood, storm damage and tsunami. SES also supports police and other services in search and rescue, major emergencies and disasters. Members of the SES are volunteers and are recruited regularly. Emergency contact - 132 500. www.ses.nsw.gov.au

Bureau of Meteorology  

Severe Weather Warnings, Severe Thunderstorm Warnings, Flood Watches and Flood Warnings are issued by the Bureau of Meteorology. They are broadcast over radio and the Bureau's website.

Stormwater

Council is responsible for managing stormwater runoff in the Warringah area. This includes providing and maintaining stormwater drainage infrastructure and managing flood-affected land. These activities are primarily funded through Council’s Environment and Stormwater Special Rate (ESSR), Infrastructure Levy and grant funding from the State and Federal Government.

Council has a large infrastructure network of over 15,000 stormwater pits and 315km of stormwater pipes and channels. This network collects rainwater that falls on roads, roofs and gardens in small to moderate storm events. Council also maintains 107 water quality devices - gross pollutant traps that remove pollution before it reaches our waterways.

Northern Beaches Stormwater Management Plan (entire document)
(PDF, 70MB)

• Chapter 1 - Introduction (PDF, 3.6MB)
• Chapter 2 - Consultation (PDF, 0.5MB)
• Chapter 3 - Existing Catchment Conditions (PDF, 16MB)
• Chapter 4 - Catchment Management Values (PDF, 1.2MB)
• Chapter 5 - Stormwater Management Objectives (PDF, 6.4MB)
• Chapter 6 - Stormwater Management Issues (PDF, 4.5MB)
• Chapter 7 - Existing Stormwater Management (PDF, 6.6MB)
• Chapter 8 - Potential Stormwater Management Options (PDF, 5.3MB)
• Chapter 9 - Evaluation of Management Options (PDF, 6.7MB)
• Chapter 10 - Adopted Managment Plan (PDF, 18.2MB)
• Chapter 11 - Implementation (PDF, 10.9MB)
• Figures (PDF, 4.4MB)
• Appendix A - EPA Directives (PDF, 5.1MB)
• Appendix B - Stakeholder Workshop Minutes (PDF, 2.8MB)
• Appendix C - Community Workshop Findings (PDF, 8.7MB)
• Appendix D - Questionnaire Findings (PDF, 15.4MB)
• Appendix E - Description of Typical Stormwater Quality Treatment Measures (PDF, 5.5MB)
• Appendix F - Pollutant Load Contribution from State Roads (PDF, 0.7MB)
• Appendix G - Existing Stormwater Pollutant Loads (PDF, 1.7MB)
• Appendix H - Pollutant Load Contribution from Sewer Overloads (PDF, 0.4MB)
• Appendix I - Bibliography (PDF, 3.8MB)
• Appendix J - RTA Funding Allocation (PDF, 2MB)