Flood classifications in A best practice guide for local governments Interpreter Document details Security classification: Public Date of review of security classification: June 2020 Authority: Queensland Reconstruction Authority Document status: Final Version: 1.0 The Queensland Government is committed to providing QRA Reference: DOC/19/62305 accessible services to Queenslanders from all culturally and linguistically diverse backgrounds. If you have difficulty in Copyright understanding this publication, you can access the Translating This publication is protected by the Copyright Act 1968. and Interpreting Services via www.qld.gov.au/languages or by © The State of Queensland (Queensland Reconstruction phoning 13 14 50. Authority) June 2020. Disclaimer Licence While every care has been taken in preparing this publication, the State of Queensland accepts no responsibility for decisions or actions taken as a result of any data, information, statement or advice, expressed or implied, contained within. To the best of This work is licensed by State of Queensland (Queensland our knowledge, the content was correct at the time of Reconstruction Authority) under a Creative Commons Attribution publishing. (CC BY) 4.0 International licence. To view a copy of this licence, visit: www.creativecommons.org/licenses/by/4.0/ Consultation In essence, you are free to copy, communicate and adapt this Developed in consultation with the Bureau of Meteorology. publication, as long as you attribute the work to the State of Queensland (Queensland Reconstruction Authority). Copies Copies of this publication are available on our website at www.qra.qld.gov.au/flood-classifications

Image: (cover) Gauge, located at Bedourie, Further copies are available upon request to: (below) Flooding, Fitzroy , Rockhampton, 2011, Queensland Reconstruction Authority (right) manual gauge, Fitzroy River. PO Box 15428 City East QLD 4002 Phone (07) 3008 7200 [email protected] www.qra.qld.gov.au

2 | Flood classifications in Queensland – A stepbest -practiceby-step guideguide forfor locallocal governmentsgovernments About this guide

Flood classifications in Queensland – Audience for this guide A best practice guide for local governments The intended audience for this guide is primarily local The aim of this guide is to assist Queensland’s local government authorities, however additional audiences governments to understand: may include: • flood classifications • local disaster management groups • river heights and flood forecasts • district disaster management groups • different types of gauges • emergency and disaster management stakeholders • flood warnings based on a river height and professionals • how to determine and set flood classifications • state and federal government agencies • considerations when reviewing flood • experts across the range of natural disasters, hazards classifications and risk management • roles and responsibilities of key stakeholders. • non-government organisations who have a role in prevention, preparedness, response and recovery. The guide has been developed in consultation with the Bureau of Meteorology (the Bureau). It clearly Resilient Queensland outlines the four steps for local governments to be able to review flood classifications: This guide is an initiative of Resilient Queensland 2018- 1. map community assets 2021, and aligns with all four objectives of the 2. relate impacts to a gauge or forecast location Queensland Strategy for Disaster Resilience: 3. identify impacts and link to a gauge height 1. We understand the potential disaster risks we face 4. consider community education and awareness 2. We work together to better manage disaster risk (flood mapping). 3. We seek new opportunities to reduce disaster risk 4. We continually improve how we prepare for, respond to and recover from disasters.

Flood classifications in Queensland – A best practice guide for local governments | 3 Contents

About this guide 3 Understanding floods 5 Flood Warnings in Queensland: Roles and responsibilities 6 Flood classifications 7 River heights and flood forecasts 8 Gauge types and functions 9 Describing the Flood Warning Service 10 Setting flood classifications 11 Considerations when reviewing flood classifications 12 Initial sources of flood information 13 Step-by-step guide to review flood classifications 14 Step 1. Map community assets 15 Step 2. Relate impacts to a gauge or forecast location 16 Step 3. Identify impacts and link to a gauge height 17 Step 4. Community education and awareness (flood mapping) 22 Ongoing review of the flood classifications 25

Image: Flood Warning Infrastructure Network meeting, Rockhampton.

4 | Flood classifications in Queensland – A best practice guide for local governments Understanding floods

Floods are a natural part of the Queensland Floods impact on both individuals and communities, landscape. Floods vary greatly in size, extent, and have social, economic, and environmental duration and frequency. No flood is the same, and consequences. The consequences of floods, both as such floods can have different impacts. negative and positive, vary greatly depending on the location and extent of flooding, and the Sudden, heavy and intense rainfall can cause floods vulnerability and value of the natural and to quickly rise in the minutes or hours that follow. constructed environments they affect. These are known as flash floods and are typically associated with relatively small catchment areas. Through data collection and analysis, city administrators, hydrologists, engineers and Floods can occur slowly in large catchment areas, planners identify and delineate those areas likely to where rainfall can build up over hours, days or be exposed to flood waters and where possible weeks. The runoff from this rainfall may create mitigate the likely impacts of future floods. significant floods that inundate large areas of land for days, weeks or months. Therefore a flood prediction and or warning is of little value unless the community understands what it means with regards to the likely impact and what they need to do in response to their individual situation.

Channel of a river Useful resource

The Bureau of Meteorology has published an Town article titled Explainer: what is a flood? (2019) to help us understand floods, what causes floods, and how to know if there’s one on the way.

The article also contains educational videos that cover understanding floods, topographic drainage divisions and river regions.

Flood hazard area, for http://media.bom.gov.au/social/blog/2156/exp example the 100 year lainer-what-is-a-flood/ floodplain

Image: (top) Flooding, Fitzroy River, 2011.

Flood classifications in Queensland – A best practice guide for local governments | 5 Flood warnings in Queensland: Roles and responsibilities

In Queensland, the effectiveness of the flood warning The Service Level Specification (SLS) for Flood system depends on the cooperative involvement of the Forecasting and Warning Services for Queensland Bureau of Meteorology (the Bureau), Queensland Version 3.1 (2018) is provided to Queensland by the Government agencies and local governments working Bureau, in consultation with the Queensland Flood with flood-threatened communities. Warning Consultative Committee.

The roles and responsibilities of all key stakeholders The SLS describes the flood forecasting and warning involved in the provision of a flood warning service in services provided by the Bureau for Queensland and Queensland are described in the National is available at Arrangements for Flood Forecasting and Warning http://www.bom.gov.au/qld/flood/brochures/QLD_S (Bureau of Meteorology, 2015) available at LS_current.pdf. http://www.bom.gov.au/water/floods/document/Natio nal_Arrangements_V4.pdf. Queensland flood forecast locations The SLS provides Queensland’s full list of forecast Coordination of the development and operation of flood locations in the SLS (Schedule 2 on p18) which warning services in Queensland is via the Queensland includes station owners, gauge type, and flood Flood Warning Consultative Committee (FWCC), a joint classification. Commonwealth, state and local government committee chaired by the Bureau.

Local government responsibilities The National Arrangements for Flood Forecasting and Warning state that in Queensland the establishment of flood classification levels rests with local government, in consultation with the Bureau.

These levels are determined by local government, based on the Bureau’s standard descriptions of flood effects, historical data and relevant local information. After councils determine the level and impacts, these are used by the Bureau when flood warnings are issued for the location.

Flood classifications can be revised at any time and should be reviewed if there have been any changes to infrastructure or flood behaviour that impacts a community. Image: (inset) The Service Level Specification and Warning Services for Queensland – Version 3.1 . Image: (top) Flinders Highway bridge damage, Monsoon Trough, . 2019.

6 | Flood classifications in Queensland – A best practice guide for local governments Flood classifications

The Bureau of Meteorology (the Bureau) uses a three tiered classification scheme that defines Useful resource flooding as minor, moderate or major at key river height stations, known as the river gauge Video: The Bureau of Meteorology video titled locations. Each classification is defined by the Understanding Flood Classifications explains water level that causes certain impacts upstream the Minor, Moderate and Major flood and downstream of the station. These levels have classifications, and the difference between been determined and described based on flood watches and warnings. It is available on standard descriptions of flood effects (see YouTube at: below), historical data and relevant local https://www.youtube.com/watch?v=gKDPgp5D information. s9s

MINOR FLOODING - Causes inconvenience. Low- lying areas next to watercourses are inundated. Minor roads may be closed and low-level bridges submerged. In urban areas inundation may affect some backyards and buildings below the floor level as well as bicycle and pedestrian paths. In rural areas removal of stock and equipment may be required.

MODERATE FLOODING - In addition to the Minor flood effects, the area of inundation is more Useful resource substantial. Main traffic routes may be affected. Manual 21: Flood Warning (2009) from the Some buildings may experience water above the Australian Disaster Resilience Knowledge Hub at floor level. Evacuation of flood affected areas www.knowledge.aidr.org.au (Note: This manual may be required. In rural areas removal of stock was under review at the time of publication) . is required.

MAJOR FLOODING - In addition to the Moderate flood effects, extensive rural areas and/or urban areas are inundated. Many buildings may be affected above the floor level. Properties and towns are likely to be isolated and major rail and traffic routes closed. Evacuation of flood affected areas may be required. Utility services may be impacted.

Image: (top) Flooding, .

Flood classifications in Queensland – A best practice guide for local governments | 7 River heights and flood forecasts

Understanding river heights The Bureau uses hydrological computer models to determine: We can significantly improve the disaster resilience • how much rainfall will run off different parts of of Queensland communities by increasing our the catchment understanding of flood risk, river height levels and • how water from different tributaries converges impacts, and flood warning systems. in the river network • how long it will take for runoff to reach major Rainfall and river height level data is published on waterways the Bureau’s website at • time water will take to travel to known points in http://www.bom.gov.au/qld/flood. This the river system. information is used by emergency services and other operational agencies, commercial Flood warning infrastructure businesses and the public to monitor rainfall and river conditions. There are various types of flood warning infrastructure that capture data and information for The Bureau uses the data it collects for enhanced the Bureau. hydrological modelling used for flood predictions. Rain gauges monitor the amount of rain falling on a River heights can be referenced to key locations or catchment. relevant landmarks (e.g. nearby crossings/bridges or causeways), and referenced to the levels at River gauges measure water levels along our river which flooding can affect residential and other systems. buildings, and cropping/grazing land. Satellites, radars, rainfall and river level gauges are Community engagement is an important step generally the tools that the Bureau uses for their during any review of flood classifications. When the warning predictions. impacts and consequences of rising river water are understood by the community, flood warnings are Manual rain and river gauges are read by at their most effective. volunteers who visit the gauge and report to the Bureau on the amount of rain that has fallen or the Flood forecasts height of the river on an hourly or daily basis.

Flood forecasts are critical to emergency responses Automatic rain and river gauges use a range of to avoid loss of life and limit property damage. sensors that relay data to the Bureau on a real time basis either using 3G/4G or VHF. Flood forecasters at the Bureau rely heavily on real- time data from radars, rainfall and river water heights. Image: (top) Automatic gauge at Emerald, Eastern Side, Central Highlands Regional Council.

8 | Flood classifications in Queensland – A best practice guide for local governments Gauge types and functions

Images: Types of gauges A. Automatic rain gauge B. Automatic rain and river gauge with a manual river gauge used as a backup C. Department of Natural Resources, Mines and Energy (DNRME) gauge hut used for water quality, water management, capturing rainfall and river flood height D. Automatic water level gauge usually found in creek systems E. Rain and river height gauge with a camera F. Manual river height gauge G. Manual river height gauge H. Manually read rain gauge

A B C D

E F G H

Image: (top) DNRME Gauge, .

Flood classifications in Queensland – A best practice guide for local governments | 9 Diagram: The various types of gauges placed in a catchment to allow the Bureau to provide effective and timely flood warning.

Describing the Flood Warning Service

The Bureau will provide detailed flood warnings for Information location key locations and general flood warnings to other An information location is a location at which locations, which typically include a statement about: observations of water level data are provided, and • reference to the relevant flood classification which where flood classifications (minor, moderate or provides potential impact information major) are defined. • current and expected levels of flooding at a key location Forecasts of projected future water levels are not • weather forecast provided. • latest available observations of river height and rainfall in the area. Information locations also assist the Bureau with warnings to forecast locations. To assist in describing a Flood Warning Service, the gauge locations where river height observations are made are categorised into three types: Data location • forecast location A data location is a location for which only the • information location observed water level data is provided. • data location. Flood classifications (minor, moderate or major) are not available for these locations and forecasts Forecast location of future water are not produced. A forecast location as outlined in Schedule 2 of the Service Level Specification is a location for which the Data locations provide the Bureau with data to Bureau provides a forecast of a future water level make predictions at information locations and either as the class of flood that is predicted (minor, forecast locations. moderate or major) or as a level and class e.g. 4.6 metres – MAJOR flood level.

10 | Flood classifications in Queensland – A best practice guide for local governments Setting flood classifications

Local governments in Queensland, through their Local Disaster Management Group In Queensland the establishment of (LDMG), are responsible for the initial flood classification levels determination, review and update of flood rests with local government, classifications in their area. This is done in in consultation with the Bureau. consultation with the Bureau and other relevant state agencies (e.g. Sunwater) so they accurately reflect the impacts at key river Flood classifications allow the expected or height stations. observed impact and severity of flooding to be clearly communicated and understood by Based on that information the Bureau will the: ensure that flood watches and warning advices are relevant and effective. a. community b. State Disaster Coordination Centre Additionally, flood classifications require (SDCC) regular review to ensure they continue to reflect the expected or known flood impacts. c. Australian Government Crisis Local development or changes to infrastructure Coordination Centre (AGCCC) in some (e.g. bridges/levees) are common reasons that situations. flood classifications may require review. There is a risk that incorrect flood Flood classifications for all stations in classifications can breed complacency in the Queensland are part of the Flood Warning community – “it’s just another major flood.” Network and are listed by the Bureau in the SLS. The SLS is generally updated on an annual basis. Image: (top) Flooding, Idalia, Townsville, 2019. Image (below): Example from the SLS.

Flood classifications in Queensland – A best practice guide for local governments | 11 Considerations when reviewing flood classifications

The following checklist is provided as a guide for  Investigate whether there have been any flood the review of flood classifications. studies or modelling undertaken in the area since the last review of flood classification  Check current flood classifications and when that might provide more information and they were last reviewed / updated. context.

 Determine, if possible, how the existing flood  Check if the river height station has been classifications were established (i.e. based on relocated, rebuilt or modified in any way since past floods, survey details, or detailed flood the flood classifications were last reviewed. mapping). Has the gauge zero (point above which the water level is measured) been adjusted? Is  Collect all of the available sources of flood there a confusion as to which river height impacts. This may include the identification of station is the point of reference? flood marks or debris lines, which can be surveyed for extra context. This data  Determine if there has been any development collection process is likely to include a cross- or physical changes in the area (e.g. levee section of stakeholders from local, state and construction, bridge works) since the flood federal agencies as well as asset classifications were last reviewed / updated. infrastructure owners, the general public and business owners in the community.  If there is no impact or community consequence at a location, there may not be a  Check to see what critical infrastructure and need for a flood classification. Sometimes the other important community infrastructure has original reason it was put in place is no longer been surveyed (or needs to be) and could be relevant e.g. a bridge that previously flooded affected or impacted e.g. bridge decks and has been raised or recent mitigation works approaches, community facilities, habitable have alleviated the risk and community floor areas for at risk locations, etc. impacts.

 Check if the flood classifications are in line  Once flood classifications are updated, with the expected or known flood impacts community education is required to ensure across the community, as per flood the changes are well understood. Ensure the classification definitions (minor, moderate, updates are added to the disaster and major). management, sub plans and operating procedures for both the Local Disaster  Check if the flood classifications and impacts Management Group (LDMG) and District are reflected in the current local disaster Disaster Management Group (DDMG). management plans, arrangements, sub plans and any other associated plans. Image: Flood Warning Infrastructure Network workshop, Cloncurry, September 2019.

12 | Flood classifications in Queensland – A best practice guide for local governments Initial sources of flood information

Flood classifications are impact-based. All available Local knowledge information, including flood mapping and local knowledge, needs to be assessed in determining the Local knowledge is invaluable and is considered by flood classification. the Bureau as the most critical of information sources. Flood mapping Local knowledge is likely to be held by council staff, Outputs from flood studies provide an initial disaster management agencies (including SES), assessment into the probable flood extent and generational landowners and residents, the Bureau, potential impacts as well as a flood height at a known state water agencies, catchment management gauge location. authorities and other interested parties.

Flood classifications are linked to on-the-ground impacts. Outputs of a flood study are primarily used for land use planning purposes to identify those areas that are most at risk of flooding. They also provide a visual representation of possible flood inundation.

Image: (above) Example of a flood map showing the flood extent of a modelled event. Graphic: (above) The relationship between flood classification Image: (top) Currawong Station on the , near Mitchell. and community impacts .

Flood classifications in Queensland – A best practice guide for local governments | 13 Step-by-step guide to review flood classifications

Four steps to review flood classifications

The four steps to review flood classifications are outlined in the following sections of this guide: Step 1. Map community assets

Step 2. Relate impacts to a known river gauge or forecast location

Step 3. Identify the community impacts and link them to a gauge height

Step 4. Community education and awareness (flood mapping)

Image: (top) Courtesy of Queensland Museum Network, photo by Gary Cranitch, (inset) Warwick flood classification board.

14 | Flood classifications in Queensland – A best practice guide for local governments Step 1. Map community assets

Map your important community assets Data sources Flood classifications are in place to understand Primary sources include: how things the community values may be impacted • council asset databases (the council asset during a flood event. databases are always the primary point of truth) Key considerations • any existing flood studies • What are the important assets to the • local knowledge community? • historical records. • What are the important assets for council that if impacted will affect service delivery? Secondary sources include: The first step in the process is to map the area of • Queensland Globe (QGlobe) interest and surrounding area, including • Queensland Emergency Management Risk community assets such as: Framework (QEMRF) data catalogue. • building and infrastructure • human and social aspects (parks, areas of Checklist - Before you move to Step 2 cultural importance, etc.)  There is survey data of critical locations • roads, bridges and other transport that can be related to a river gauge. infrastructure  Map (printed or in digital form) clearly • environmental assets identifies the important community assets • economic assets impacted. • other points of interest.  Guidance from the community and relevant interests defines the important community Assistance assets. For local governments with access to a GIS system,  Critical infrastructure that will affect service seek assistance from your spatial team for this delivery, if impacted, has been identified. task.

For local governments without a GIS capability, utilise the Queensland Globe (seek training from the Department of Natural Resources, Mines and Energy if you have not used it before). The Queensland Globe is published at: https://qldglobe.information.qld.gov.au/

Image: (top) Flooding in central Ipswich, 2011.

Flood classifications in Queensland – A best practice guide for local governments | 15 Step 2. Relate impacts to a gauge or forecast location

Relate impacts back to a known gauge or For initial detail on this gauge, key flood heights forecast location are recorded at each forecast location within a catchment. It is likely that the Bureau may hold The first step to link impacts back to a known additional information for all of the other stations gauge or forecast location is understanding where in the catchment area so it is worthwhile the gauges are located. involving the Bureau at this stage.

The Bureau provides river height brochures and flood warning network maps to assist council in Useful resources building this knowledge. Flood Warning in Queensland Each river brochure outlines flood risk, current http://www.bom.gov.au/qld/flood/brochure flood classifications, and most importantly a table s/qld/fld_qld.shtml that summarises the flood history of the named river catchment. Queensland River Maps http://www.bom.gov.au/qld/flood/brochure Select or confirm the gauge that will be used. s/river_maps.shtml

Image: An example of flood history tables for the Fitzroy River.

16 | Flood classifications in Queensland – A best practice guide for local governments Step 3. Identify impacts and link to a gauge height

Templates to identify impacts and link these to a gauge height

Sample templates on the following pages demonstrate how councils can identify impacts and link them to a gauge height for minor, moderate and major flood classifications.

The sample templates are available for download at: www.qra.qld.gov.au/flood-classifications.

Image: (top) Manual gauge at Charleville which is the forecast location, (right) Burdekin Cislowski Road, Plantation Creek.

17 | Flood classifications in Queensland – A best practice guide for local governments Flood classification Impact Yes / no (where) Expected Height height of at (Forecast location) impact gauge MINOR Inconvenience Yes No 1.2m 3.5m example: Bottom of Lemke Causes inconvenience. Park next to river and Low-lying areas next to playground watercourses are Low lying Yes No 1.25m 3.5m inundated. Minor roads areas may be closed and low- example: Yorks Flats along level bridges submerged. with Kerry Rd In urban areas inundation Minor roads Yes No 1.2m 3.6m may affect some closed backyards and buildings example: End of Blacks Rd below the floor level as and Jeremy St well as bicycle and Low level Yes No pedestrian paths. In rural bridges areas, removal of stock and equipment may be Inundation in Yes No 1.3m 3.7m required. urban areas example: Stafford Lowlands and parts of Anzac Avenue Backyards Yes No 1.3m 3.7m inundated example: Backyards along Jeremy St in Stafford Lowlands, approx. 14 backyards Buildings Yes No below floor level Bicycle and Yes No pedestrian paths impacted Stock are Yes No 1.3m 3.7m being moved example: Properties along to higher Yorks Flats next to river are ground moving cattle Farm Yes No 1.25m 3.5m equipment example: Pumps and being moved irrigation equipment being moved along upper Shaw Rd adjacent to Spring Creek

18 | Flood classifications in Queensland – A best practice guide for local governments Flood classification Impact Yes / no (where) Expected Height height of at (forecast location) impact gauge

Yes No MODERATE Inundation in some areas example: End of Chambers 2.6m 5.2m In addition to the minor is more Rd is now closed. Chambers effects, the area of substantial Flat and surrounding areas inundation is more are inundated substantial. Main traffic Yes No routes may be affected. Main traffic Some buildings may be routes may example: Main axis route into 2.7m 5.3m affected above the floor be affected township (Flinders Hwy) is level. Evacuation of closed to the north flood affected areas may Yes No be required. In rural Some example: Buildings in areas, removal of stock buildings are likely to be Ramsey Industrial estate are is required. 2.8m 5.4m affected being impacted above floor above floor level. Just for Cars and level Detroit Diesel businesses are being inundated Evacuation of Yes No flood affected areas may be required Yes No example: All stock along Stock needs properties within Chambers to be moved Flat, Ferry Downs, Johnstone 2.6m 5.2m to higher Pike and Tree Tops are being ground inundated. Stock are currently being moved to higher ground

Farming Yes No equipment example: All properties along (pumps and eastern side of Charmeston 2.6m 5.2m irrigation River down to Peaks Crossing lines) need to will need to move farming be moved equipment

19 | Flood classifications in Queensland – A best practice guide for local governments Flood Impact Yes / no (where) Expected Height at classification height of gauge impact (Forecast location) Yes No MAJOR Extensive rural areas are example: Chambers Rd is 4.3m 6.7m In addition to the inundated and now closed. All properties moderate effects, isolated along Road are now extensive rural inundated areas and/or Urban areas are Yes No urban areas are inundated and in example: All streets inundated. Many some areas around Kitchener Rd are 4.4m 6.8m buildings may be islands with inundated and isolated affected above the isolation are floor level. identified Properties and towns are likely to Many buildings are Yes No be isolated and impacted and example: approx. 107 4.4m 6.8m major rail and affected above homes within Boundary traffic routes floor level Suburb are effected closed. Evacuation of flood affected Yes No Properties and areas may be townships are Example: Tree Tops and required. Utility 4.5m 6.9m likely to be Ferry Downs are now services may be isolated isolated. Township of Ferry impacted. Downs is affected heavily Yes No

Major rail and example: Main line at Tree traffic routes are Tops and Ferry Downs is 4.5m 6.9m closed closed. Main traffic route north is closed in multiple locations Yes No

Evacuation of flood example: All properties affected areas may along eastern side of 4.5m 6.9m be required Charmeston River down to Peaks Crossing will need to move farming equipment Yes No

Utility services All services in Tree Tops, 4.5m 6.9m may be impacted Ferry Downs, Scatia Plains and Kamarooka are impacted

20 | Flood classifications in Queensland – A best practice guide for local governments Communicatingthe hazard River flood effects 4.0m 3.5m 4.5m 5.5m 5.0m 6m 6.5m 6.7m 7.6m 7.0m Height consequences of rising water during a flood. This is Example: River flood impacts 1.8m 2.3m 3m a – – – n example example n of river floodinformation shared with a community impactthe on and                   Impacts As the River level rises River level theAs McGlad Roadarea into Overflow flooding toRoadliable are River and SouthCarnarvon East roadby isisolated Carnarvon Nine Old River Road Southacrossflows Water beclosed mustroad and the turnoff atGeraldton Highway Coastal West North seversWater flowing breakoutsAll freeboard feet) (4 metres1.22 with Bridge Nine Mile at metresor 7.61 flood 1961withstand to designed Townlevees Flats Bay ofNickol outflowing Water floodedCarnarvon East Roadflooded River South Lewers isovertopped Bibbawarra Crossing Lewers Island offLewerscut and 110 113 assessments throughoverflows Gully Crossing ofPlantation west km 1.1 approximately Road River severed North Nicol Bay Creek starts backing up backing starts Creek flowing commences Creek - Mile Bridge isovertopped Bridge Mile Flats 21 | Flood Flood classifications in Queensland the flow is reversed as water flows out ofoutflows wateras isreversed flow

– A best practice guide for local governments

MINOR MODERATE MAJOR Step 4. Community education and awareness (flood mapping)

Community education and awareness about flood Education and information flood maps should relate to maps and / or mapping products are vital for the levels on stream gauges via the following two communication of flood behaviour and the hazard. processes:

Maps are a useful tool, however, community 1. Mapping of flood model results at increments that education should be based around the community directly correlate to levels on the gauge (rather impacts, possible consequences, and actions in than peak values). Depending on local flood response at various gauge levels. Refer to the graphic behaviour, this might be at half metre increments “Communicating the hazard” on the previous page. or coarser / finer increments as warranted.

Community engagement communication materials Additional levels relating to planning and critical should recognise that your community will have infrastructure for example (such as development different needs in interpreting flood information so levels or levee immunity levels) are also valuable the style of communication will need to cater to for emergency management purposes and should different needs. be described in public information.

2. Inclusion of a location-specific flood totem icon or Useful resources sign that displays: • the flood classifications of minor / moderate / major flood levels (if available) Community Engagement Framework • peak levels of historic flood (noting the date (Handbook 6) produced by Emergency of the flood) Management • relevant design flood levels (particularly the https://knowledge.aidr.org.au/resources/ha Defined Flood Event) ndbook-6-community-engagement- • levels of local landmarks (such as the town framework/ bridges or the local post office steps).

Building Resilience to Natural Disasters – Where a flood height relates to a particular level Collaboration Guide available at on the gauge, this value should also be clearly https://www.qra.qld.gov.au/resilient- highlighted on the totem. queensland/collaboration-guide

Image: (top) Example of a flood map showing flood extent at 5.4m on the gauge at Killarney (flood evacuation map, yellow zone).

22 | Flood classifications in Queensland – A best practice guide for local governments Building community awareness and education Key messages

It is important to commence active and targeted Flood classifications need to be meaningful and community engagement and education in the review relevant to the community before and during a flood process and after changes to the flood warning event as they are built into to the warnings issued by service have been formalised by the Bureau. the Bureau.

Community meetings, media releases, social media Therefore accurate flood classifications are required posts with supporting brochures and handouts that to ensure that relevant warnings are issued and to identify the hazard, likely impact and consequences of ensure that the community properly understands the rising water and actions are methods that may be likely impacts and consequences to rising water and utilised to deliver this message in preparation for what to do in response. future events. A change to flood classifications does not change It is important that any community engagement has a flood readings. In other words, a 6m flood is still a 6m clear aim, objectives and succinct key messages. flood and will have the same impact and effects. Outlined below is a generic starting point councils might use. If flood classifications are understated, we expose our community to risk. Any review will determine whether Aim this should be called a minor, moderate or major flood • Review flood classifications within the council area level. against the decision-making framework and national guidelines for flood warnings as outlined in this document. Supporting material and resources Objectives • Identify those in the community who receive flood Resources, supporting material and examples are warnings and public information available from • Local Government Authorities, • Identify the impacts that must be communicated • the Queensland Reconstruction Authority and, during flood events • The Bureau of Meteorology. • Identify the range of community understanding of flood classifications, what it means to them and A resource sheet is provided on the following page. what do they do with the information • Identify to what extent relevant impacts can be inferred from predictions at the particular forecast location • What actions do you expect the community to take at various gauge heights as forecasted by the Image: resilience workshop. Bureau?

23 | Flood classifications in Queensland – A best practice guide for local governments Educational videos

The Queensland Reconstruction Authority (QRA) The video topics include: has produced a series of short educational videos • Understand your flood risk to help Queenslanders understand flood risk at: • Flood warnings https://www.qra.qld.gov.au/understand-your- • Flash flooding flood-risk • Riverine flooding • How Queensland’s river catchments work.

Understanding flood classifications Fact sheet examples

To assist with community awareness, councils Many councils provide examples of interactive can also link to the Bureau’s educational video flood mapping on their websites to assist local on flood classifications. residents to determine their flood risk.

Image: Southern Downs Regional Council has a number of The video is available at: good examples of flood emergency action guides that explain flood classifications and how to use maps. These are available https://www.youtube.com/watch?v=gKDPgp5 on Council’s website at Ds9s&feature=youtu.be https://www.sdrc.qld.gov.au/council/disaster- management/flood-fact-sheets-and-information

24 | Flood classifications in Queensland – A best practice guide for local governments Ongoing review of the flood classifications

Once the flood classifications have been assessed Therefore, an annual assessment of flood impact is for a local government area it is important to keep encouraged across all councils to ensure flood them relevant. classifications remain consistent with expected impacts at the particular location. Development of any nature can occur in a floodplain. This may either positively or negatively A simple example of how this can be recorded is impact flood effects and likely consequences on a set out below. town, locality or infrastructure. If a change is required follow the process outlined Development of particular note includes bridge and in this document starting with Step 1. other river crossing upgrades and flood mitigation works like a levee or creek diversion.

Forecast Location (Name of location) Flood Classification Revised Height at Date Next assessment Gauge MINOR 3.5m 22 Aug 2019 22 Aug 2021 MODERATE 5.2m 22 Aug 2019 22 Aug 2021 MAJOR 6.9m 22 Aug 2019 22 Aug 2021

Image: (top) Diamantina Shire Council.

25 | Flood classifications in Queensland – A best practice guide for local governments Images: Condamine flood classification board. (Right) Automatic rain and river gauge with camera, Diamantina. Image: Condamine flood classification board. www.qra.qld.gov.au/resilient-queensland