Flooding is a natural event that befalls when large volumes of water covers a dry land. In Australia, flooding is a very important issue because it affects many lives and properties. It is the most costly and devastating natural disaster in the country (Office of the Queensland Cheif Scientist, 2011). On average, 1.3 million homes in Australia are at a risk of being affected by flooding. Floods are caused by different factors and they have varied effects on communities. For this reason, it is important to understand the causes and effects of flooding so as to identify suitable approaches of preventing and minimizing consequences of flooding. Since 1800s, there have been a lot of changes and developments regarding management of floodplains in Australia. Several flood risk management policies and programs have been developed with an aim of keeping communities informed on how they can become resilient as regards to planning for, preventing, responding to and recovering from floods.
Floods in Australia are largely caused by abnormally heavy rainfall. These natural events are common in Australia and cost Australians millions of dollars every year. From 1852 to 2011, at least 951 people are estimated to have been killed, 1326 others injured and property worth about $4.76 billion damaged as a result of floods in Australia (Carbone & Hanson, 2012). The Australian government has developed several floodplain risk management policies and laws aimed at developing strategic flood protection approaches so as to eliminate or reduce impacts of flooding (National Flood Risk Advisory Group, 2008). In February 2011, the Council of Australian Governments (COAG) adopted the “National Strategy for Disaster Resilience” (McLuckie, Babister, Smith, & Thomson, 2014) also known as the Strategy. The main goal of this Strategy was to improve the country’s resilience to natural disasters through adoption of flexible disaster management approaches.
The Strategy has played a major role in enhancing floor risk management in communities. Some of the documents that have been developed specifically for flood risk management in Australia include: Australian Emergency Management (AEM) Handbook 7, AEM20 (Flood Preparedness), AEM21 (Flood Warning), AEM22 (Flood Response), AEM23 (Emergency Management Planning for Floods Affected by Dams), and AEM39 (Flood rescue boat operation) (Australian Emergency Management Institute, 2014). There is also the floodplain risk management policy that has been developed to eliminate or reduce flooding impacts and liabilities. Development of this policy was prompted by occurrence of floods in various parts of Australia that left hundreds of people dead and properties worth billions of dollars destroyed.
This report comprehensively covers the present-day state of managing floodplain risks in Australia. The report covers three main areas. First is comprehensive discussion of floodplain risks. Second is analysis of floodplain risk management. Third is discussion of floodplain risk management framework, including decisions that are made in relation to floodplain risk management. Lastly is analysis of involvement of the three levels of government in floodplain risk management.
Risk and risk management
Risks are inevitable when discussing about floodplains not only in Australia but in any part of the world. It is through understanding of risks associated with floodplains that proper risk management practices can be developed. Therefore these practices can only be developed if the behaviors of floods are analyzed and understood by the concerned persons or authorities. Understanding various aspects of floodplains helps relevant authorities to make informed and efficient decisions with high levels of confidence knowing that they will help in protecting lives, properties and the environment. Therefore it is important to understand the meaning of risk and risk management before starting to discuss floodplain risk management process and framework.
Definition of risk
When describing risk, it is not just about the change that results from occurrence of an event. Flooding has adverse effects on the safety and health of people and communities and the built environment. Flooding brings about different risks depending on the kind of interaction between floods and the community (Australian Emergency Management Institute, 2013). For these risks to be analyzed appropriately, likelihood of flooding ad their consequences’ severity must be understood (McLuckie D. , Best practice in flood risk management in Australia, 2012). These likelihoods and consequences vary from one floodplain to another thus analysis of risks may have to be done by looking at the uniqueness of each floodplain.
Generally, a flood that has a 1% AEP (annual exceedance probability) is likely to occur in every 100 years. Nevertheless, consequences of this kind of flood may vary from place to place. Additionally, it is worth noting that when an event happens, its consequence is what must be dealt with. For example, the 1% AEP flood may have varied consequences in different locations. When this flood occurs in one place, its consequence may only be shallow flooding of a few houses, whereas occurrence of the same flood in another place may have catastrophic consequences. Therefore risks have to be established based on combination of likelihood of an occurrence in a particular area and its consequence. Table 1 below shows clarifications of floodplain risks severity considering its likelihood and consequence (McLuckie & Toniato, 2015)
Floods are generally known for their negative outcomes but they may also have positive outcomes (WaterConnect, 2015). For example, flooding can cause loss of property and jeopardize people’s safety, which are negative consequences. On the other hand, flooding may also result to improvement of agricultural productivity and replenishment of groundwater and surface water supplies (Alberta WaterPortal, 2013). In general, floods have social, environmental and economic consequences. Therefore it is important to consider both the positive and negative outcomes of a flood when evaluating risks of a floodplain.
There are 2 main elements that must be considered when analyzing flood risks: danger or hazard to people’s safety and loss of property. The main goal of flood risk management is to minimize the likelihood and consequence of these hazards and losses. For this to be achieved, well-thought management plans must be analyzed comprehensively and implemented so as to make flood prone areas more resilient to floods.
In flooding, there are three main kinds of risks that should be managed: existing flood risk, future flood risk and residual flood risk. Existing flood risk refers to the risk linked to current developments taking place in the floodplain. This risk’s likelihood and/or consequence can be reduced by building a levee around the development even though there is a possibility of this levee being overtopped resulting to a more worse consequence. Thus when looking at how to manage this kind of risk, it is more important to find ways of eliminating the consequence rather than minimizing the occurrence likelihood.
Future flood risk refers to the risk linked to future developments that have been planned in a given floodplain. This kind of risk can be managed by analyzing and selecting suitable construction sites and also establishing appropriate minimum height of floor levels. Cities can improve management of this kind of risks through strategic land-use design. Residual or continuing flood risk refers to the risk that remains after implementation of risk management measures to prevent or mitigate existing and future flood risks. Existence of residual flood risks is due to the fact that it is physically, environmentally and economically impossible to eliminate them. These risks cannot be addressed by regulatory or physical floodplain management actions (Australian Institute for Disaster Resilience , 1999).
2. Merit based approach and strategic assessment
2.1. Merit based approach
NWS has been in the forefront to enact laws aimed at enhancing flood protection. Stringent planning controls were largely used but NSW residents largely opposed them in early 1980s. This prompted a change in flood management strategy to a one inclined to risk management approach. As a result, two policies were developed: 1984 NSW Flood Prone Land Policy and 1986 Manual (McLuckie D. , Practical Management of Flood Risk, 2015). The NSW government emphasized on two main facts when formulating these policies. The first was that areas prone to floods are valuable resources that should not be excluded from development unnecessarily.
The second was that treating development on the same basis could lead to unnecessary rejection and restriction of some developments. The main objective of developing merit based approach policy was to minimize flooding impact and liability on individual land owners and occupiers, and to reduce public and private losses caused by flooding. Some of the provisions in the policy included: construction of physical structures protecting flooding and minimizing flood impacts, allowing purchase of property located in the most risky places, lifting uncalled-for development restrictions and controls, merit based approach aimed at enhancing development in areas prone to floods, and application of reasonable and effective development controls and restrictions to manage likely flood losses in new development areas.
NSW Policy also outlined responsibilities of various participants in flood risk management. The local government had the greatest responsibility whereas state government provided financial and technical support. Implementation of the policy was done through floodplain management process targeting to manage present and future flood risks resulting from riverine flood events. The basic meaning of merit based approach is that floodplain management measures are developed based on the unique characteristics of the area in addition to consideration of relative flood risks. This approach is still the basis of current flood management practices.
This approach was quite successful in managing development within areas prone to flooding across NSW State but it also became apparent that failure to safeguard existing development and control future development growth was also posing great flood risks. It basically meant that residual or continual risks were great and could not be ignored. This was later proved by Nyngan event of 1990, Coffs Harbour event of 1996 and Wollongong event of 1998. Since the release of 1986 Manual, numerous revisions have been done by successive governments to improve flood protection measures while upholding the fundamental merit based approach and continuing to consult the communities concerned.
2.2. Strategic management
Significant revisions were made to the NSW Manual in 2001 and 2005. Various authorities worked together and released “Floodplain Management in Australia: Best Practice Principles and Guidelines” in 2000. The revisions made focused more on environmental issues and also took an all-inclusive methodology to floodplain management. The strategic approach was based on considering a wide range of factors associated with flood events and their impacts, and involving as many participants as necessary. The strategic approach is still being applied until today. This approach requires coordination of various multidisciplinary agencies across all the three levels of government. It also requires support from professionals (including floodplain managers, hydrologists, engineers, environmental managers, land-use planners, emergency response managers, etc.) and non-government organizations. These multidisciplinary teams come up with recommendations to decision makers on the best ways of managing flooding risks on existing and future communities and protect the built environment.
Strategic management approach creates room for development of more effective practices by use and consideration of more accurate and reliable data, advanced analysis techniques, development growth and changing climate. This approach also facilitates lasting community resilience and sustainable flood management.
Nevertheless, flood risk management practices still vary greatly from one area to another in Australia. This is not just at territory or state level but also at local and regional levels. This is due to varying flood risk severity across the country and other factors such as governance, societal, and resourcing priorities. All the same, proper flood risk management requires adequate planning, preparation, coordination, response and recovery.
3. Floodplain risk management process
Floodplain risk management (FRM) process is a very crucial component of the Floodplain Development Manual of 2015 (Department of Infrastructure, 2005). This manual was particularly formulated to help councils in developing appropriate flood management plans for different flood prone areas. The overall steps involved in FRM process is as shown in Figure 1 below
3.1. FRM committee
The first step of FRM process is for the local council to form a FRM committee. This committee is chaired by the council and it includes: elected council members, council staff from planning, engineering and environmental departments, local community representatives, relevant industry representatives, DIPNR (department of infrastructure, planning and natural resources) officers and state emergency service (SES) representative(s). The committee plays an advisory role and has no formal powers. Its major role is to help the council to develop and implement suitable management plans within the council’s areas of jurisdiction. The committee discusses varied views on technical, ecological, economic and social issues.
3.2. Data collection
A wide range of data is necessary to analyze flood behavior and costs, effectiveness and benefits of different flood management approaches. Available data should be defined so as to establish the missing data. The management committee initiates studies to collect the necessary data to help in preparation of effective floodplain risk management plans. This data is very useful in decision making process by the council and committee. Some of the data collected include: land use and historic flood data, rainfall records and projections, geological and topographical data, existing FRM measures, existing and planned development and land use trends, current development controls and zonings related to floods, individual and community flood readiness levels, possible community disruptions resulting from flooding, local recharge areas and groundwater, climate change data, etc. The council appoints consultants who collect the necessary data. Some of the contemporary studies performed during data collection process are: land use planning, environmental and cultural studies.
3.3. Flood study
This is a wide-ranging technical study carried out to determine flood behaviour. The study defines the extent and nature of flood problem by providing the following information: velocity, level and extent of floodwaters and flood flow distribution across different areas of the floodplain. A flood study has two main components: hydrologic aspects and hydraulic aspects. The former entails approximation of flood discharges for floods with different severities while the later entails determining water depths, velocities and levels of flooding. As a result of this, flood studies are completed by developing hydraulic and hydrological models of the floodplain being investigated. When undertaking a flood study, all potential hazards associated with the flood should also be extensively assessed (Smith, Davey, & Cox, 2014). Climate change is another component that is considered when carrying out a flood study.
3.4. FRM study
This is a multidisciplinary and detailed study carried out with an aim of identifying, analyzing and comparing different risk management alternatives and identify prospects for environmental improvement. This study combines the findings of data collection and flood study exercises. The information gathered helps in strategic analysis of impacts of various management alternatives of flood risks. It is usually a complex process as it involves combining varied alternatives so as to come up with the best mix. The study assesses three main categories of risks: existing risks, future risks and continuing risks. The main steps followed when carrying out a FRM study are: community consultation, categorization of hydraulic and hazards, strategic analysis of new development areas, selection of flood planning level (FLP), analysis of flood damage, identification and analysis of flood risk management options, preparation of relevant information for targeted users and the general public, analysis of issues of concern, and recommendations. The council appoints consultants who carry out this study.
3.5. FRM plan
This is where selected floodplain risk management practices are presented to the public then feedback welcomed and used to make necessary revisions and/or improvements. These plans should be the best and most effective practices for managing floodplains (Babister & Rtallick, 2013). The plan contains the information necessary to facilitate development planning for the flood prone area. This plan is prepared after analyzing all the data collected in previous processes. It contains opinions from the local community and professionals on how the flood prone land can be properly developed without posing great risks to personal safety and property damage. FRM plan also helps in: optimizing utilization of community infrastructure, reducing personal hazards to local residents, emergency response personnel and visitors, and purposefully analyzing land that can be developed in the future, among others. This plan must be prepared professionally and the community should be involved in its review. After review process, the council together with other relevant participants should adopt the plan ready for implementation.
3.6. Plan implementation
This is the last and critical step of FRM process. Implementation is done by following the priorities identified for various management practices that are contained in the FRM plan. The priorities are made by considering the following factors: effectiveness of the practices, resourcing needed, how quick they can be adopted, existing constraints of implementing the practices, and how the constraints can be addressed. As a result of this, high priority is given to measures that are more effective, can be implemented immediately and are low cost. These priorities are used to develop the implementations strategy. The main objective of implementing the FRM plan is to ensure that all flood risks are managed effectively through a wide range of identified practices and by following the implementation program created in the plan.
4. Floodplain risk management framework and key issues addressed
FRM framework provides floodplain management entities (FMEs) with a basis to perform their role of improving flood risk management in the areas of their jurisdictions. FMEs are government agencies mandated to oversee management of flood risks within their service areas. Successful management of flood risks requires a lot of efforts, commitment, resources and support from all stakeholders, including the general public. FRM framework provides a robust and comprehensive approach for managing flood risks. This is done through assessment and understanding of various elements associated with flood occurrence and risks. Using FRM framework, FMEs are able to understand flood events in a particular area, existing management measures, their effectiveness and deficiencies, and how this information can be used to protect the community and future development against floods.
FRM framework helps FMEs to: have a better understanding of FRM roles and responsibilities so as to engage appropriate agencies in managing flood risks; understand relevant regulations, legislation, guidance and policies; contemplate on community profile; gather relevant data and use it properly; identify and analyze knowledge gaps so as to make informed decisions; develop and adopt plans aimed at improving knowledge about flood risks and their management; make informed decisions regarding development in floodplains; and consult key stakeholders and the community. Figure 2 below is a schematic diagram of FRM framework.
From Figure 2 above, FME has to address a number of issues first because proceeding to other steps of the FRM framework. Once the issues have been addressed, the subsequent steps involve: assessment of floodplain management processes for specific flood prone areas; collection of relevant data, undertaking flood studies, carrying out floodplain management studies, developing floodplain management plans, and implementing the developed plan (Moreton Bay Regional Council, 2015). These processes are performed in a similar way as those discussed in FRM process section above.
As aforementioned, FME uses the FRM framework in Figure 2 above to manage flood risks by addressing several key issues. These issues are discussed below
4.1. Risk management methodology
Risk managers use risk management processes for systematic identification and assessment of risks, and develop effective measures of controlling these risks. This is very helpful for proper planning on how to manage risks with greater certainty. The National Emergency Risk Assessment Guidelines contain the significance of this methodology.
4.2. Sensible governance engagements
FRM framework creates a basis to identify, monitor, maintain and communicate sensible governance engagements that FME is using to manage flood risks. This includes legislations, policies, roles and responsibilities of various government stakeholders. When overseeing flood risk management, FME must seek advice and support from state and territory governments and also consult and involve local communities in their plans and activities. The FRM framework provides guidance on the structures that government entities should put in place to assist FMEs.
4.3. Managing floodplain management framework
Flood risk management is a complex and challenging process. FRM framework provides guidance on formation of an administrative committee to oversee implementation of flood risk management plans. The committee comprises of various members and has specific mandate within its service area.
4.4. Relevance of understanding flood behaviour
For flood risks to be managed effectively, flood behaviour must be understood first. There are several factors that influence flood behavior. FRM frameworks helps to assess these factors and use the information collected to develop and implement effective measures that will protect the flood prone area, community and present and future developments (McLuckie, Kandasamy, Low, & Avery, 2010).
4.5. Providing flood information
Information is very important when dealing with flood risk management. Stakeholders use this information to make decisions that determine the type of measures implemented in various flood prone areas. FRM framework emphasizes on the relevant information to be collected, how it should be collected, terminologies to be used and efficient ways of sharing it with targeted users and the public. Keeping everyone informed about flood risks and FRM processes helping in drawing support from relevant participants and the community. Therefore relevant, complete and accurate data should be collected and shared with people through effective education programs and awareness campaigns.
4.6. Sharing information from knowledge hub
Knowledge hub is a very essential component of FRM framework. However, it only becomes useful if the information collected from it is appropriately shared with the relevant stakeholders. Flood information should be shared with relevant government agencies, stakeholders and the community. These persons and entities should be adequately informed about various issues such as flood risk management plans, flood emergency and disaster response plans, land-use planning, development decisions, etc. This is achieved through creation of a communication plan, which ensures that every entity or person receives the information they need at the right time. Sharing of information also enhances participation of stakeholders because they will always want to give feedback. Figure 3 below shows how communication about flooding is done from the knowledge hub
4.7. Handling knowledge and management gaps
Information collected in the knowledge hub also provides a unique opportunity for FMEs to establish and analyze knowledge and management gaps. This kind of gaps adversely affect efforts made towards flood risk management. Once the gaps are identified, stakeholders should plan on how to fill them by understanding relevant studies.
5. Key end users and information needed
Any information about flooding and flood risks have to be collected with the end users in mind. The information can only be helpful if it is understood and used by the end users appropriately. In other words, the way end users understand this information determines the effectiveness of using the information to manage flood risks. Some of the end users include: federal government, state governments, local governments, council staff, SES, public infrastructure developers, land-use planners, private developers, flood risk managers, emergency managers, insurance companies and the public. Each of these group use the information for different purposes but the common goal is to ensure that people and properties are protected against flood risks.
The information may be used to control and assess development in flood prone areas, prepare flood plans for specific areas, consider potential flood risks when planning for future developments, assess existing flood risk management practices, etc. The information that is usually needed include: flood frequencies, extent, water depths and velocities of flooding, flood behaviour, history of floods, population in flood prone areas, current flood risk management practices and their effectiveness, costs and shortcomings, predicted flooding patterns, etc.
6. Three levels of government
The three levels of Australian governments work jointly to ensure effective management of floods. Each of these governments has a significant role to play (Council of Australian Governments (COAG), 2011).
6.1. Federal government
The federal government of Australia works together with state and local governments for managing floods across the country. Some of the roles played by the federal government include: facilitating coordination of relevant national departments; formulating, maintaining and monitoring flood risk management policies; providing technical and financial support; providing emergency response services; assisting in proper land-use planning; sharing information with the general public about flooding and flood management practices and plans; development of appropriate infrastructure for flood risk management; data management, flood forecast and warning services, including development of their associated infrastructure; and protection of environmental values and natural resources of national importance (Australian Institute for Disaster Resilience, 2013).
6.2. State government
It is responsible for: supporting flood management policies through formulation of necessary legislations; defining broad objectives of the policies formulated, such as developing relevant manuals; providing specialized technical support and advice; providing financial support; coordinating relevant state agencies, and providing emergency management services. Some of the state agencies involved in FRM include: DIPNR, SES, Department of Community Services, Bureau of Metrology, Department of Environment and Conservation (DEC), Department of Primary Industries (DPI) and Office for Emergency Services.
6.3. Local government
The local governments, also referred to as councils, play a critical role in flood management in Australia. These governments identify the necessary flood studies to be carried out, depending on the specific demands of their service areas, and use the data collected to plan and management development in flood prone areas. Other roles played by local governments include: monitoring local developments, asset management through flood mitigation works, issuance of planning certificates, flood education, emergency response and data collection following a major flood event.
Office of the Queensland Cheif Scientist. (2011). What are the consequences of floods? Retrieved September 6, 2017, from https://www.chiefscientist.qld.gov.au/publications/understanding-floods/flood-consequences
Carbone, D., & Hanson, J. (2012). Top 10 worst floods in Australia. Retrieved September 6, 2017, from https://www.australiangeographic.com.au/topics/history-culture/2012/03/floods-10-of-the-deadliest-in-australian-history?utm_source=dlvr.it&utm_medium=twitter
National Flood Risk Advisory Group. (2008). Flood risk management in Australia. Australian Journal of Emergency Management , 23 (4), 21-27.
McLuckie, D., Babister, M., Smith, G., & Thomson, R. (2014). Updating national guidance on best practice flood risk management. Sydney: National Flood Risk Advisory Group.
Australian Emergency Management Institute. (2014). Handbook 9: Australian Emergency Management Arrangements (2nd ed.). Canberra: Australian Emergency Management Institute.
Australian Emergency Management Institute. (2013). Australian Emergency Management Handbook 7: Managing the Floodplain Best Practice in Flood Risk Management in Australia. Canberra: Australian Emergency Management Institute.
McLuckie, D. (2012). Best practice in flood risk management in Australia. Brisbane: Australian Emergency Management Institute.
McLuckie, D., & Toniato, A. (2015). Planning for flood risk. Sydney: NSW Office of Environment and Heritage.
WaterConnect. (2015). Floods have both positive and negative consequences. Retrieved September 6, 2017, from https://www.waterconnect.sa.gov.au/Hazard-Management/SitePages/What%20are%20the%20impacts%20of%20floods.aspx
Alberta WaterPortal. (2013). Environmental impacts of flooding. Retrieved September 6, 2017, from https://albertawater.com/what-are-the-consequences-of-flooding/environmental
Australian Institute for Disaster Resilience . (1999). Managing the floodplain. Canberra: Emergency Management Australia.
McLuckie, D. (2015). Practical Management of Flood Risk. Sydney: NSW Office of Environment ans Heritage.
Department of Infrastructure, P. a. (2005). Floodplain development manual: the managment of flood liable land. Sydney, NWS, Australia: New South Wales Government.
Smith, G., Davey, E., & Cox, R. (2014). Flood Hazard Water Research Laboratory Technical Report 2014/07. Water Research Laboratory.
Babister, M., & Rtallick, M. (2013). Benchmarking best practice in floodplain management. Tweed Heads: Floodplain Management Association.
Australian Institute for Disaster Resilience. (2013). Handbok 7: Managing the floodplain: a guide to best practice in flood risk management in Australia. Canberra: Australian Institute for Disaster Resilience.
Moreton Bay Regional Council. (2015). Floodplain risk management framework. Queensland: Queensland Government.
McLuckie, D., Kandasamy, J., Low, A., & Avery, D. (2010). Managing risk to existing development and managing risk to future development. In Floodplain risk management. Sydney: University of Technology.
McLuckie, D., & Edwards, M. (2013). Managing the floodplain: a guide to best practice in flood risk management in Australia. Canberra: Australian Emergency Management Institute.
Council of Australian Governments (COAG). (2011). National strategy for disaster resilience. Canberra: COAG.