Flood risk management

Floodplain development Studies and plans Climate change LeveesFloodplain Management Committee Property development

Managing flood risk

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Tweed Shire Council is responsible for managing flood risk in the Tweed.

Council is responsible for:

  • developing and managing flood-prone land
  • providing flood maps
  • reducing damage from floods
  • maintaining our flood infrastructure (levees, pump stations, flood gates)

Council's flood risk management policy(PDF, 105KB) is guided by the NSW Government's floodplain development manual.

Floodplain development

Floodplain refers to all flood prone areas in the Tweed.

Land development in flood prone areas

Standards for land development in flood prone areas are outlined in Council's Development Control Plan(PDF, 785KB). To minimise flooding impacts on the community all floodplain development must met these standards.

Floor levels

All habitable development must have a floor level above the 'flood planning level'. This is based on a 1% annual exceedance probability flood (AEP) plus 0.5 metre freeboard.

Flood liable land

Council defines land as flood liable if it’s affected by the probable maximum flood (PMF), which is the largest flood that could conceivably occur at a particular location.

Flood management planning instruments

A planning instrument is a document adopted under planning legislation by state, territory or local government. Planning instruments manage the use and development of land:

Studies and plans

Murwillumbah CBD Levee and Drainage Study (2018)

This study looks at flood behaviour when the Murwillumbah CBD Levee, the East Murwillumbah Levee and the Dorothy/William Streets Levee are overtopped, and drainage behind the levees.

Murwillumbah CBD Levee and Drainage Study Volume 1 of 2 - Report Text and Appendices(PDF, 35MB)

Murwillumbah CBD Levee and Drainage Study Volume 2 of 2 - Figures(PDF, 24MB)

Coastal Creeks Floodplain Risk Management Study and Plan (2015)

The second of four floodplain risk management studies in the Tweed area. This study identifies current and future flood risks, reviews flood mitigation options and considers the best ways to manage flood prone land.

Tweed Coastal Creeks Floodplain Risk Management Study(PDF, 8MB)

Tweed Coastal Creeks Floodplain Risk Management Plan(PDF, 10MB)

Tweed Valley Floodplain Risk Management Study and Plan (2014)

This plan looks at flood risks in the Tweed Valley and provides a range of floodplain management measures. The study and plan were placed on exhibition for public comment and the Frequently Asked Questions are a response to community questions.

Tweed Valley Floodplain Risk Management Study 2014(PDF, 113MB)

Tweed Valley Floodplain Risk Management Plan 2014(PDF, 34MB) 

Tweed Valley Flood Study (2009)

A study into the flood behaviour of the Tweed River and its major tributaries, from Boat Harbour and Byangum upstream of Murwillumbah to the river mouth at Tweed Heads.

The study area includes Murwillumbah, Condong, Tumbulgum, Chinderah, Kingscliff, Fingal Head, Banora Point, Tweed Heads, Tweed Heads South and Tweed Heads West.

The addendum provides scenarios for potential impacts of climate change (sea level rise and increased rainfall intensity).

Tweed Valley Flood Study 2009(PDF, 6MB)

Tweed Valley Flood Study 2009 - Climate Change(PDF, 3MB)

Tweed-Byron Coastal Creeks Flood Study (2009)

A study into the flood behaviour of four coastal creeks: Cudgen, Cudgera, Mooball and Marshalls Creeks.

A joint study between Tweed and Byron Shire Councils (reflecting the cross-boundary flooding between Mooball and Marshall Creek).

The study area includes South Kingscliff, Cabarita - Bogangar, Hastings Point, Pottsville, Burringbar, Mooball, Crabbes Creeks, Wooyung, South Golden Beach, Billinudgel, New Brighton and Ocean Shores.

The study provided model scenarios for possible future changes in land use (e.g. agricultural change from sugar cane production) and potential impacts of climate change (sea level rise and increased rainfall intensity).

Coastal Creeks Flood Study(PDF, 10MB)

Coastal Creeks Flood Study flood maps addendum(PDF, 14MB)

Climate change and rising sea levels

In 2008 the NSW Government issued guidelines for councils to include climate change variables into flood studies.

Since then all our flood studies have included climate change modelling that considers:

  • a sea level rise of 0.91 m
  • an increase in rainfall intensity of 10%

Climate impact maps

Maps of climate change scenarios are available in our flood studies above. In 2010 Council adopted these climate change maps as appendices to our Development Control Plan.

The maps are applied as design flood levels for large scale greenfield residential subdivisions, such as Cobaki, Kings Forest and West Kingscliff.

Flood infrastructure

Flood levees map(PDF, 3MB)

Council carries out regular testing and maintenance on our levees, flood gates and pump stations. While it’s reassuring to have these in place, the risk of flood remains. 

Levees

Levees are built to provide protection from flooding. Levees are used to contain, control or divert the flow of water. However, no levee is flood-proof.

Since the 1950s Council has operated a series of flood levees throughout the Tweed:

  • Murwillumbah CBD levee
  • East Murwillumbah levee
  • Dorothy and William Streets levee
  • Tweed Heads South levee
  • South Murwillumbah levee (minor)
  • various rural levees
    (around 40 kilometres in total)

Do you live behind a levee?

Know your risk if you live behind a levee. There may be little warning when a levee is about to overtop and it could lead to very fast flooding. 

Find out:

  • where levees are located (see levee map above)
  • the height of floodwater the levees are designed for

Take action:

  • have an emergency action plan
  • know your evacuation route and when you need to evacuate
  • listen for warnings (radio, TV and internet)

Levee myths factsheet (SES)

Video: When the Murwillumbah levee breaks (2018)

This video shows a 500-year flood in Murwillumbah’s central business district.

When the Murwillumbah levee overtops, the CBD will be under 4 metres of water in less than 3 hours.

(There’s a 0.2 per cent chance of the simulated 500-year average recurrence flood happening in any year.)

Video: Levee protection restored for South Murwillumbah (2020)

The video shows repairs to South Murwillumbah riverbank 

In March 2017 floods undercut the South Murwillumbah riverbank and broke the crest of the flood levee. Repairs were completed in February 2020, using more than 25,000 tonnes of rock.

Council received $3.75 million from the Australian Government’s Natural Disaster Relief and Recovery Arrangements.

Floodgates

Council maintains a network of around 350 sets of floodgates. These are generally ‘flap gates’ that allow water to flow in one direction only. These stop floodwater backfilling areas behind levees and allow drainage once flood levels drop.

Flood pumping stations

There are two Council operated flood pumping stations, located in the Murwillumbah CBD. They pump water away that builds up behind the levees.

Pumping stations do not remove the flood risk completely - flooding of roadways and private property may still occur.

Council's Floodplain Management Committee

The Tweed Floodplain Management Committee provides a forum to discuss technical, social, economic, environmental and cultural issues associated with floodplain management.

The Committee includes representatives from Council, State Emergency Service, NSW State Government and the local community.

For terms of reference, agendas and minutes see Council committees.

Property development

Contact Council's Flooding and Stormwater Engineer on 02 6670 2400 if you have questions about flood-related property development.