Floodplain Inundation Analysis Combined with Contingent Valuation: Implications for Sustainable Flood Risk Management

In recent decades, the Pearl River Delta (PRD) region has experienced strong economic and population growth. By 2050 120 million people are expected to live in the region, which currently has eleven major cities, and the emerging mega-city formed by Hong Kong, Shenzhen and Guangzhou. The populous coastal cities and low lying flood plains in the PRD experience flood risk via: (i) intense precipitation from storms, (ii) inland pluvial flooding, (iii) storm surges. Climate change, including global sea level rise forecasts of more than 1 m by 2100, mean that flood risk is expected to increase in future. Sustainable flood risk management (SFRM) must be adopted to mitigate these risks. Strategies such as the UK's ‘making space for water’ programme seek to tackle flood risk through planning, but such a strategic approach is not evident in the PRD. Recent coastal land reclamation projects in the PRD illustrate the conflict between urban growth pressure and flood risk, and that more comprehensive, or sustainable, flood risk management is not currently practiced. This paper examines flood risk management practice in the PRD. It starts with a theoretical sustainable flood risk appraisal (SFRA) template developed from literature and global best practice, against which PRD practice is benchmarked. The paper discusses a case study in Hong Kong and Shenzhen where in-depth discussions with more than 30 stakeholders were held to understand barriers and constraints to realising SFRM. This research seeks to further the practice of SFRM in the PRD, and comparable urbanising mega-deltas in the region.

Mitigation of flood damage has accompanied the development of human cultures. Flood remains one of the biggest natural hazards threatening the prosperity of modern society. Flood related fatalities and damages continue to increase over the world. Flood research and flood protection policy is currently dominated by a technical world view. The recent decades however foresee the importance of social and socio-economic aspects due to expansive and intensified land use and the rising damage potentials in floodplain areas (Schanze 2002, Messner and Meyer 2005). The lesson from hurricane Katrina presses embracing a sustainable flood risk management strategy, which requires integration of both structural and non-structural measures. An optimal flood risk management can be achieved only by concerted implementing both non-structural and structural measures. Such strategies will contribute to a sustainable flood risk management practice. The core of flood risk management lies in the proper planning and policy design to form an appropriate feedback loops in the engineering and social-economic system. This paper gives an overview about the existing and emerging practice over the world to implement sustainable flood risk management.

Abstract. Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological, and economic themes into their flood risk management (FRM) practices. However, the justifications for SFRM are still somewhat embryonic, and it is not yet clear whether this concept is influencing current policies in different countries. This paper reviews the past and current flood management experiences from flood defence to SFRM in four developed countries to highlight lessons for coastal megacities in development. The paper explores recent strategies such as “Making Space for Water”, Planning Policy Statement 25 (PPS25), and the National Planning Policy Framework (NPPF) in the UK and “Room for the River” in the Netherlands, which were implemented to mitigate flooding, integrate FRM with sustainability concepts, and deliver sound FRM practice for future generations. In this context, the United States has also established a National Flood Insurance Program (NFIP), and in a different approach, Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies give good lessons in achieving long-term SFRM to deliver sound flood management practices considering socio-economic and environmental concerns. Most developing coastal megacities especially in Asia are still heavily reliant on a traditional hard-engineering approach, which may not be enough to mitigate substantial risks due to human factors (e.g. large population, rapid socio-economic growth, subsidence from excessive groundwater extraction) and natural factors (e.g. climate change including sea-level rise and land subsidence). It is clear that different countries and cities have their interpretation of SFRM, but this paper explores how policymakers can adopt “mixed options” to move towards long-term thinking about sustainability with social, economic, and environmental considerations.

Recent flood events in western Europe have shown the need for improved flood risk management along the Rhine and Meuse rivers. In response, the IRMA-SPONGE research programme was established, consisting of 13 research projects, in which over 30 organizations from six countries co-operated. The aim of IRMA-SPONGE was the development of methods and tools to assess the impact of flood risk reduction measures and of land-use and climate change scenarios, in order to support the spatial planning process for the Rhine and Meuse River Basins. Several important conclusions were agreed upon by participants in the programme; they emphasize the role of spatial planning, especially in areas at risk of flooding, as an important component of flood risk management: 1 Flood risk, defined as a function of both flood probability and potential damage, is increasing not only due to climate change (likely to cause an increase in the probability of extreme discharges) but also due to continued investment in areas at risk of flooding (resulting in an increase in potential damage). 2 Water retention areas and land-use adaptations far upstream may be useful in lowering the frequency of floods in small basins. However, extreme floods far downstream in the lower Rhine and Meuse basins, where the probability of design discharges is less than 1/200 per year, cannot be prevented by such upstream measures. 3 The most effective and sustainable reduction of flood risks could be achieved by reducing the potential damage (vulnerability) in flood-prone areas through adapted land use and spatial planning. 4 Flood risk management organizations should not only aim at a reduction of flood risk but should also seek to enhance the ecological quality of rivers and floodplains.

Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological and economic themes into their flood risk management (FRM) practices. However, justifications for SFRM are still embryonic and it is not yet clear whether this concept is influencing the current policies in different countries. This paper reviews the past and present flood management approaches and experiences from flood defence to FRM in four developed countries with the aim of highlighting lessons for developing mega deltas. The paper explored recent strategies such as “Making Space for Water, PPS 25, and NPPF” in the UK; “Room for Rivers” in the Netherlands which was promoted to cope with flooding, integrate FRM with ideas on sustainability, and deliver good FRM practice for next generations. The United States has also established a sound National Flood Insurance Program (NFIP), and Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies showed some good lessons to achieve long term SFRM direction to deliver flood management practices with social-economic and environmental concerns. Most of developing coastal megacities especially in Asia are still heavily reliant on traditional hard-engineering approach, that may not be enough to mitigate substantial risks due to human (exist huge populations, rapid socio-economic growth, subsidence) and natural (climate change) factors. We understand different countries and cities have their own interpretation on SFRM, but recommend policy makers to adopt “mixed options” towards thinking about long term and sustainability that with social, economic and environmental considerations.

Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological and economic themes into their flood risk management (FRM) practices. However, justifications for SFRM are still embryonic and it is not yet clear whether this concept is influencing the current policies in different countries. This paper reviews the past and present flood management approaches and experiences from flood defence to FRM in four developed countries with the aim of highlighting lessons for developing mega deltas. The paper explored recent strategies such as “Making Space for Water, PPS 25, and NPPF” in the UK; “Room for Rivers” in the Netherlands which was promoted to cope with flooding, integrate FRM with ideas on sustainability, and deliver good FRM practice for next generations. The United States has also established a sound National Flood Insurance Program (NFIP), and Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies showed some good lessons to achieve long term SFRM direction to deliver flood management practices with social-economic and environmental concerns. Most of developing coastal megacities especially in Asia are still heavily reliant on traditional hard-engineering approach, that may not be enough to mitigate substantial risks due to human (exist huge populations, rapid socio-economic growth, subsidence) and natural (climate change) factors. We understand different countries and cities have their own interpretation on SFRM, but recommend policy makers to adopt “mixed options” towards thinking about long term and sustainability that with social, economic and environmental considerations.

Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological and economic themes into their flood risk management (FRM) practices. However, justifications for SFRM are still embryonic and it is not yet clear whether this concept is influencing the current policies in different countries. This paper reviews the past and present flood management approaches and experiences from flood defence to FRM in four developed countries with the aim of highlighting lessons for developing mega deltas. The paper explored recent strategies such as “Making Space for Water, PPS 25, and NPPF” in the UK; “Room for Rivers” in the Netherlands which was promoted to cope with flooding, integrate FRM with ideas on sustainability, and deliver good FRM practice for next generations. The United States has also established a sound National Flood Insurance Program (NFIP), and Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies showed some good lessons to achieve long term SFRM direction to deliver flood management practices with social-economic and environmental concerns. Most of developing coastal megacities especially in Asia are still heavily reliant on traditional hard-engineering approach, that may not be enough to mitigate substantial risks due to human (exist huge populations, rapid socio-economic growth, subsidence) and natural (climate change) factors. We understand different countries and cities have their own interpretation on SFRM, but recommend policy makers to adopt “mixed options” towards thinking about long term and sustainability that with social, economic and environmental considerations.

Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological and economic themes into their flood risk management (FRM) practices. However, justifications for SFRM are still embryonic and it is not yet clear whether this concept is influencing the current policies in different countries. This paper reviews the past and present flood management approaches and experiences from flood defence to FRM in four developed countries with the aim of highlighting lessons for developing mega deltas. The paper explored recent strategies such as “Making Space for Water, PPS 25, and NPPF” in the UK; “Room for Rivers” in the Netherlands which was promoted to cope with flooding, integrate FRM with ideas on sustainability, and deliver good FRM practice for next generations. The United States has also established a sound National Flood Insurance Program (NFIP), and Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies showed some good lessons to achieve long term SFRM direction to deliver flood management practices with social-economic and environmental concerns. Most of developing coastal megacities especially in Asia are still heavily reliant on traditional hard-engineering approach, that may not be enough to mitigate substantial risks due to human (exist huge populations, rapid socio-economic growth, subsidence) and natural (climate change) factors. We understand different countries and cities have their own interpretation on SFRM, but recommend policy makers to adopt “mixed options” towards thinking about long term and sustainability that with social, economic and environmental considerations.

<strong class="journal-contentHeaderColor">Abstract.</strong> Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological, and economic themes into their flood risk management (FRM) practices. However, the justifications for SFRM are still somewhat embryonic, and it is not yet clear whether this concept is influencing current policies in different countries. This paper reviews the past and current flood management experiences from flood defence to SFRM in four developed countries to highlight lessons for coastal megacities in development. The paper explores recent strategies such as “Making Space for Water”, Planning Policy Statement 25 (PPS25), and the National Planning Policy Framework (NPPF) in the UK and “Room for the River” in the Netherlands, which were implemented to mitigate flooding, integrate FRM with sustainability concepts, and deliver sound FRM practice for future generations. In this context, the United States has also established a National Flood Insurance Program (NFIP), and in a different approach, Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies give good lessons in achieving long-term SFRM to deliver sound flood management practices considering socio-economic and environmental concerns. Most developing coastal megacities especially in Asia are still heavily reliant on a traditional hard-engineering approach, which may not be enough to mitigate substantial risks due to human factors (e.g. large population, rapid socio-economic growth, subsidence from excessive groundwater extraction) and natural factors (e.g. climate change including sea-level rise and land subsidence). It is clear that different countries and cities have their interpretation of SFRM, but this paper explores how policymakers can adopt “mixed options” to move towards long-term thinking about sustainability with social, economic, and environmental considerations.

Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological and economic themes into their flood risk management (FRM) practices. However, justifications for SFRM are still embryonic and it is not yet clear whether this concept is influencing the current policies in different countries. This paper reviews the past and present flood management approaches and experiences from flood defence to FRM in four developed countries with the aim of highlighting lessons for developing mega deltas. The paper explored recent strategies such as “Making Space for Water, PPS 25, and NPPF” in the UK; “Room for Rivers” in the Netherlands which was promoted to cope with flooding, integrate FRM with ideas on sustainability, and deliver good FRM practice for next generations. The United States has also established a sound National Flood Insurance Program (NFIP), and Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies showed some good lessons to achieve long term SFRM direction to deliver flood management practices with social-economic and environmental concerns. Most of developing coastal megacities especially in Asia are still heavily reliant on traditional hard-engineering approach, that may not be enough to mitigate substantial risks due to human (exist huge populations, rapid socio-economic growth, subsidence) and natural (climate change) factors. We understand different countries and cities have their own interpretation on SFRM, but recommend policy makers to adopt “mixed options” towards thinking about long term and sustainability that with social, economic and environmental considerations.

<strong class="journal-contentHeaderColor">Abstract.</strong> Sustainable flood risk management (SFRM) has become popular since the 1980s. Many governmental and non-governmental organisations have been keen on implementing the SFRM strategies by integrating social, ecological, and economic themes into their flood risk management (FRM) practices. However, the justifications for SFRM are still somewhat embryonic, and it is not yet clear whether this concept is influencing current policies in different countries. This paper reviews the past and current flood management experiences from flood defence to SFRM in four developed countries to highlight lessons for coastal megacities in development. The paper explores recent strategies such as “Making Space for Water”, Planning Policy Statement 25 (PPS25), and the National Planning Policy Framework (NPPF) in the UK and “Room for the River” in the Netherlands, which were implemented to mitigate flooding, integrate FRM with sustainability concepts, and deliver sound FRM practice for future generations. In this context, the United States has also established a National Flood Insurance Program (NFIP), and in a different approach, Japan has developed an advanced flood warning and evacuation contingency system to prepare for climatic extremes. These case studies give good lessons in achieving long-term SFRM to deliver sound flood management practices considering socio-economic and environmental concerns. Most developing coastal megacities especially in Asia are still heavily reliant on a traditional hard-engineering approach, which may not be enough to mitigate substantial risks due to human factors (e.g. large population, rapid socio-economic growth, subsidence from excessive groundwater extraction) and natural factors (e.g. climate change including sea-level rise and land subsidence). It is clear that different countries and cities have their interpretation of SFRM, but this paper explores how policymakers can adopt “mixed options” to move towards long-term thinking about sustainability with social, economic, and environmental considerations.

&amp;lt;p&amp;gt;The flood events of 13-15 July 2021 in Germany brought the relevance of flood prevention acutely and once again to our attention. As the earth's atmosphere heats up, nature has more and more intense events in store for us, which push our flood protection and management measures to their limits and beyond. For planning purposes, but also in case of an event, it is therefore highly relevant to improve the communication of uncertainties and the assessment of their potential impact, e.g. in the climate or flood forecast, in a target group-oriented manner.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In Germany and in the European Union, the conditions for flood risk management have been improved since 2007 with the implementation of the European Flood Risk Management Directive (FRMD) and the amendments to the Federal Water Act. Many new instruments such as flood hazard and risk maps, building regulations or the category of flood emergence areas were introduced. For example, flood hazard and flood risk maps and corresponding management plans have been prepared on the basis of historical discharge data, water levels and hydrological and hydraulic modelling. However, recent examples have shown that the objective of the FRMD to reduce flood-related risks to human health, the environment, infrastructure and property has only been achieved to a limited extent.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;In this paper we discuss why the developed maps and plans do not lead to a sufficient risk perception and why, in case of a flood event, it is often not clear what actions need to be taken when and by whom. For this, we want to highlight three aspects in particular:&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;1) Data: importance of using measured data and dealing with historical flood events, which are only comparable to a limited extent to today's and future conditions, which are shaped by the influences of climate change.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;2) Actors: importance of involving different actors in the flood risk management planning process to strengthen risk perception and responsibility.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;3) Communication: Importance of communicating uncertainties target group-specific and visualising uncertainties and their possible impacts context-specific.&amp;lt;/p&amp;gt;&amp;lt;p&amp;gt;For effective and sustainable flood risk management, we therefore believe that we are in need of a communication and dissemination strategy in order to contribute to a transparent description of the roles of the actors and their responsibilities. Consequently, the already developed tools (e.g. flood hazard /risk maps) should be supplemented by involving regional actors, uncertainty information and its effects should be classified and communicated to all decision-making levels in a way that is appropriate for the target group.&amp;lt;/p&amp;gt;

The Pearl River Delta (PRD) region has experienced rapid economic and population growth in the last three decades. The delta includes coastal megacities, such as Hong Kong. These low-lying urbanised coastal regions in the PRD are vulnerable to flood risks from unpredictable climatic conditions. These can result in increasing storm surges, rising sea level and intensified rainstorms causing coastal and inland flooding, all of which impact the delta. This paper has taken the coastal megacity of Hong Kong as a case, focusing on two study sites: Shenzhen River and Tai O town, chosen for their peculiar inland and coastal flood problems. A sustainable flood risk appraisal (SFRA) template was developed against which sustainable flood risk management (FRM) practices in these sites were benchmarked. Thirty-eight stakeholders were interviewed during this research in order to understand the current FRM practices, their barriers and their constraints. It was found that FRM in the case study currently focuses on hard engineering, while neglecting other important sustainability indicators. A SFRA practice that takes public participation, equity of flood preparedness and environmental friendly into account could be effective in achieving sustainable flood risk mitigation practices in Hong Kong and other coastal cities in the PRD.

Water related natural hazards and climate change issues such as flood has become a serious threat to the lives, livelihoods and sustainable development of Bangladesh. Chilmari Upazila of Kurigram district which is one of the most seriously flood affected areas of Bangladesh has been taken as the study area. Bangladesh is already known as a role model for flood risk management around the world. But, the situation of flood management is not the same all around the country. The objectives of this study are to find out the main problems of the flood control and risk management system of Chilmari Upazila, and to develop a planning intervention guideline for its flood control and risk management. The interactive approach of the study involves participation of the stakeholders to develop local solutions to the flood problems. The empirical part of this study is conducted by household questionnaire survey and semi-structured in-depth interviews with questions regarding flood control and risk management. Main findings of the study state that the floods in Chilmari are managed in ad hoc manner. A coordinated and comprehensive management approach along with strong institutional framework is very important for sustainable flood control and risk management at Chilmari. Journal of Bangladesh Institute of Planners, Vol. 8, Dec 2015, pp. 111-121

This paper presents the challenges for effectiveness and sustainability of flood risk management strategies and technologies by critically reviewing flood management practices. The study reveals that reliable flood prediction is limited by the characterisation of floods that have multiple causes and hydrological uncertainties due to variability in climate and river morphology. Moreover, changing land use in floodplains and the potential of creating new risks limit the risk assessment and evaluation process of flood control projects. Hence, sustainability analysis mechanisms, including ‘dynamic sustainability’ concepts, should be adopted in the flood management planning process. Investigations into the proportional contribution of structural and non‐structural measures to reduce total flood risk could assist in better decision making. Gaining improved understandings of the perception on flood risk and safety, and risk communication methods, for present and future stakeholders is crucial. Extensive research on the above challenges would reveal pathways for developing sustainable flood risk management strategies.