All development on the floodplain must comply with the provisions of Development Control Plan Section A3 - Development of Flood Liable Land available from Plans, Policies and Controls
. Most types of development must address the design flood level, which is based on the 100 year average recurrence interval (ARI) flood. Design flood levels maps are attached to DCP A3 and are available on Council's online mapping system.
Council defines land as flood liable if it is affected by the probable maximum flood (PMF), which is the largest flood that could conceivably occur at a particular location. Council provides flood mapping through it's online mapping system.
, and as attachments to Development Control Plan Section A3 - Development of Flood Liable Land available from Plans, Policies and Controls
. Council's Flooding and Stormwater Engineer may be contacted for further property related flood enquiries.
The Tweed DCP Section 3 (387kB PDF) contains development standards and other provisions in respect of floodplain management in Tweed Shire and relates to Tweed Local Environmental Plan 2000 which is the principal planning instrument governing development in the Shire.
Where an inconsistency arises between this plan and any environmental planning instrument applying to the same land, the provisions of the environmental planning instrument prevail. An environmental planning instrument means a State Environmental Planning Policy, a Regional Environmental Plan or a Local Environmental Plan.
Flood Pumping Stations
Flood pumping stations are used in some areas where levees and floodgates prevent the normal street stormwater systems from draining freely to the river in times of flood. There are two Council operated flood pumping stations, both located in the Murwillumbah CBD, at Lavender Creek Commercial Road, and Wharf Park Tumbulgum Road.
Flood pumping stations pump water that accumulates behind the levee from local rainfall and runoff to the river. Pumps have a limited capacity, so rely on other public areas to provide storage of flood water, such as Knox Park. Unfortunately pumping stations cannot eliminate the flood risk behind the levee and in high volume, long duration storm events flooding of roadways and some private property may still occur.
Council undertakes regular inspections, testing and maintenance of the pumping stations. However residents are encouraged to contact Council's Customer Service
. This phone number and the name and asset number of each facility are displayed on signage on each pumping station.
Flood forecasts and warnings - Bureau of Meteorology
All weather, rainfall and flood forecasts and associated warnings are provided by the Bureau of Meteorology. Please refer to the Bureau's website: www.bom.gov.au
. For local broadcasts of weather and flooding information, please refer to the ABC North Coast Radio (FM 94.5).
Flood evacuation and emergency response - State Emergency Service
The NSW State Emergency Service (SES) is the combat agency for dealing with flood and storm emergencies, including the establishment of flood warning systems, and the evacuation and welfare of affected communities. The SES prepares Local Flood Plans for flood liable communities, which outlines the nature of the flood threat and its consequences, responsibilities of the SES and other officers and agencies, and actions to be carried out during flood emergencies. The SES will advise residents of necessary actions during floods, including when to evacuate, and where the nearest evacuation centre is located. The SES can also assist in preparing residents and businesses for flood events.
For further information see Emergency Management
Flood insurance terms, conditions and premiums are determined by the insurance industry. Flood insurance is a relatively new product, and few properties were insured against flooding (as opposed to stormwater inundation) prior to 2006. Flooding is a very costly natural disaster which affects a relatively small percentage of insured properties, and high premiums compared to other forms of risk are likely. While insurers base their assessment of properties on flood maps produced by Council, Council has no influence over the determination of flood insurance products or its premiums. Concerned customers are encouraged to speak directly to their insurer, and shop around for insurance products that suit their specific needs. For further information please see the Insurance Council of Australia
Flood Control Lot Certificate ApplicationThe Flood Certificate is a pre-requisite to a Complying Development Application under the SEPP if the property is Flood Prone.
This application is lodged by the Building Unit Administrative staff, as a RAMS certificate and a Tax Invoice is generated for customer services to process payment. The cost of this Certificate is $110.00.
The application form can be found at: Building - Flood Control Lot Certificate Application (53kB PDF).
For up to date information on road closures, refer to www.myroadinfo.com.au
. This website is a joint initiative of Northern Rivers Councils, and provides guidance on main road closures due to flooding, roadworks or other events, as they are reported.
Floodplain Risk Management
Council has adopted the floodplain risk management approach prescribed by the Floodplain Development Manual
. For further information see Council's flood and risk management studies below.
Tweed Valley Flood Study
The Tweed Valley Flood Study was initially completed in 2005, and updated in 2009 in conjunction with the Tweed Valley Floodplain Risk Management Study.
The study describes and defines the existing 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, and provides a basis for floodplain risk management activities in the future.
The study includes urban areas of Murwillumbah, Condong, Tumbulgum, Chinderah, Kingscliff, Fingal Head, Banora Point, Tweed Heads, Tweed Heads South and Tweed Heads West.
The study uses digital flood modelling (RAFTS-XP hydrologic and TUFLOW 1D/2D hydraulic models) which is calibrated against real flood events in 1989, 1978 and 1974. The models use ground data obtained by Council's 2007 Airborne Laser Scanning project, and considers flooding caused by rainfall across the catchment as well as storm surge from the ocean. Data for flood levels, depths and velocities was obtained for a range of flood sizes (5, 20, 100, 500 year ARI and the probable maximum flood PMF), and is summarised in a set of maps.
An addendum to the 2009 Study Update provides model scenarios for potential impacts of climate change (sea level rise and increased rainfall intensity).
The flood study provides the basis of Council's Tweed Valley Floodplain Risk Management Study and Plan, currently being prepared by consultants.
Tweed Valley Floodplain Risk Management PolicyFlood Risk Management Policy (227kB PDF)
Tweed Valley Floodplain Risk Management Study and Plans
Following completion of the Tweed Valley Flood Study in 2005, Council has commenced preparation of a Floodplain Risk Management Study and Plan (FRMS and P) for the Tweed Valley, from Murwillumbah to Tweed Heads. The study and plan are to be provided in accordance with the process outlined in the NSW Floodplain Development Manual.
Immediately following the 2005 Flood Study, Council prepared the first three parts of the FRMS and P. These addressed the immediate needs of Council, being the adoption of new design flood levels provided by the Flood Study (Part I); limiting the cumulative impacts of development by identifying and protecting high flood flow areas (Part II); and addressing habitable development of the floodplain to minimise the risk to human life via emergency response provisions (Part III). Following a public exhibition period these first three parts of the plan were adopted and implemented via amendments to Development Control Plan Section A3 - Development of Flood Liable Land between 2006-2008.
In 2008 Council engaged consultants BMT WBM Pty Ltd to complete the risk management process on behalf of Council. The Tweed Valley Floodplain Risk Management Study (FRMS) will assess and optimise strategies aimed at reducing the impact of flooding to both existing and future development in the study area, while the Floodplain Risk Management Plan (FRMP) will detail how flood prone land is to be managed, by adopting the preferred scheme from the FRMS. The process will be overseen by Council's Floodplain Management Committee.
An initial stage of the consultancy required an update to the 2005 Flood Study, to incorporate improved ground level data obtained from the 2007 Airborne Laser Scanning project, creation of a new hydrologic model, and utilisation of improved modelling software. This update also examined climate change scenarios.
As part of the study, a floor level survey of around 7000 flood prone residential, commercial and industrial properties has been completed. This data is used to examine potential flood damages, identify evacuation problem areas, and assess the benefits of flood mitigation options.
The Draft Tweed Valley Floodplain Risk Management Study and Plan was placed on exhibition in July / August 2012 and February / March 2014 for public comment The Study reviewed flood risk in the Tweed Valley, including risks to people and other potential impacts of flooding, and assessed a wide range of options to reduce and mange these risks. The Plan outlined the recommendations of the Study and a priotised plan to implement these. The Floodplain Management Committee reviewed the submissions and feedback, undertook additional investigations and put the revised Study and Plan to the appointed Floodplain Management Committee and Council. Tweed Shire Council adopted the Plan in September 2014.
The adopted study includes "Frequently Asked Questions" in Appendix A which addresses the most commonly raised issues from the previous exhibition period in 2012 and 2014.
Links to the adopted reporting is :-
Tweed Valley Floodplain Risk Management StudiesTweed Valley Floodplain Risk Management Study Part I - Flood Planning Levels (253kB PDF) Tweed Valley Floodplain Risk Management Study Part II - High Flow (296kB PDF) Tweed Valley Floodplain Risk Management Study Part II - High Flow Maps (1.33mB PDF) Tweed Valley Floodplain Risk Management Study Part III - Habitable Land Use on the Floodplain (193kB PDF) Tweed Valley Flood Study 2009 Update (6.04mB PDF) Tweed Valley Flood Study 2009 Update - Climate Change (2.86mB PDF)
Tweed Valley Floodplain Risk Management PlansTweed Valley Floodplain Risk Management Plan Part I - Flood Planning Levels (156kB PDF) Tweed Valley Floodplain Risk Management Plan Part II - High Flow (180kB PDF)
Since the 1980's, Council's flood studies have adopted a sea level assumption of around 2.6m AHD when considering the 100 year average recurrence interval (ARI) flood. Based on work carried out in adjoining Council areas, this level is conservative by around 0.4m. Indirectly, this conservative approach has provided some in-built allowance for sea level rise due to climate change in previous flood studies and some existing development areas.
In October 2008, the NSW Department of Environment and Climate Change (DECC, now Office of Environment and Heritage, OEH) issued a guideline for incorporating climate change variables into flood studies. Referencing this guideline, Council undertook climate change modelling of the 100 year ARI event in its 2009 Tweed Valley Flood Study Update and the 2010 Coastal Creeks Flood Study. This modelling considered two climate change parameters, being a sea level rise of 0.91m, and an increase in rainfall intensity of 10%. Maps of the climate change scenarios were produced and are available with these flood studies.
Version 1.3 of Development Control Plan Section A3 - Development of Flood Liable Land (June 2010) adopted the climate change maps as appendices to the DCP. They are applied as design flood levels for large scale greenfield residential subdivision, such as Cobaki, Kings Forest and West Kingscliff.
Council has resolved to investigate other implications of the increased flood risk due to climate change in the Floodplain Risk Management Studies currently being undertaken for the Tweed Valley and Coastal Creeks Floodplains. Responses to climate change could include:
- Revised flood planning (floor heights, fill heights) levels, building additional floodway's and levees or
- Accepting increased frequency of inundation, loss of residential freeboard and increased flood damages
Please click on the following link to view DCP Section A3 documents, Tweed Shire Council Planning Documents - Plans, Policies and Controls
Coastal Creek Flood StudyCoastal Creeks Flood Study (10.43mB PDF) Coastal Creeks Flood Study Addendums (14.22mB PDF)
The Coastal Creeks Flood Study was completed in 2010, and was a joint project between Tweed and Byron Shire Councils. The study describes and defines the existing flood behaviour of the four coastal creeks in the study area (Cudgen, Cudgera, Mooball and Marshalls Creeks) and provides a basis for floodplain risk management activities in the future.
The study includes urban areas of South Kingscliff, Cabarita - Bogangar, Hastings Point, Pottsville, Burringbar, Mooball, Crabbes Creeks, Wooyung, South Golden Beach, Billinudgel, New Brighton and Ocean Shores. The study acknowledges the interaction of flooding across the Tweed - Byron Shire boundary between Mooball and Marshall Creek, hence the joint nature of the study.
The study uses digital flood modelling (RAFTS-XP hydrologic and TUFLOW 1D/2D hydraulic models) which is calibrated against real flood events in 2005, 1987 and 1974. The models use ground data obtained by Council's 2007 Airborne Laser Scanning project, and considers flooding caused by rainfall across the catchment as well as storm surge from the ocean. Data for flood levels, depths and velocities was obtained for a range of flood sizes (5, 10, 20, 50, 100, 500 year ARI and the probable maximum flood PMF), and is summarised in a set of maps.
The study also 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).
The flood study provides the basis of Council's Coastal Creeks Floodplain Risk Management Study and Plan, currently being prepared by consultants, and expected to be completed in 2014.
Coastal Creeks Floodplain Risk Management Study and PlanFollowing completion of the Coastal Creeks Flood Study in 2010, Council has engaged consultants BMT WBM Pty Ltd to provide a Risk Management Study and Plan for the Coastal Floodplain area (Cudgen, Cudgera and Mooball Creek floodplains). The study and plan are to be prepared in accordance with the process outlined in the NSW Floodplain Development Manual.
The Coastal Creeks Floodplain Risk Management Study (FRMS) will assess and optimise strategies aimed at reducing the impact of flooding to both existing and future development in the study area, while the Floodplain Risk Management Plan (FRMP) will detail how flood prone land within the study area is to be managed, by adopting the preferred scheme from the FRMS. The process will be overseen by Council's Floodplain Management Committee.
As part of the study, a floor level survey of around 2,500 flood prone residential, commercial and industrial properties has been completed. This data is used to examine potential flood damages, identify evacuation problem areas, and assess the benefits of flood mitigation options.
The consultants have received initial feedback from community and industry groups and stakeholders on their floodplain management issues. As the study progresses and information is provide to and accepted by the Committee, further exhibition periods and public sessions will occur, to ensure that the community can provide its collective knowledge and ideas to the process.
It is expected that the study and plan will be completed in 2014.