Floods – From Risk to Opportunity
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- A framework for flood impact assessment in urban areas Michael J. HAMMOND
- Characteristics of flood disaster and evacuation activit ies of residents at Amami Oshima Island, Japan Akihiro
- A comprehensive assessment of multilayered safety in flood risk management – the Dordrecht case study FRauke Hoss
- On the implementation of floodplain management plans on the Herbert and Johnstone rivers, Australia MARK Jempson
- The VNK2-project: a fully probabilistic risk analysis for all major levee systems in the Netherlands Ruben Jongejan
- , Niels ROode
- Optimal investment in emergency management in a multilayer flood risk framework B. Kolen 1,2 M. KOK 1,3
- Long-term channel changes in the Mekong River: towards sustainable river channel management NAOKI MIYAZAWA
- Risk assessment method for flood control planning considering global climate change in urban river management MASARU MORITA
- Risk sharing in practice for Integrated Flood Management MASAHIKO murase
- Prediction of the effect of huge structures on eco-hydrological changes in Changjiang Basin TADANOBU NAKAYAMA 1 ,2 DAVID SHANKMAN 3
- Educational activities for urban flood damage reduction using unique facilities Keiichi TODA
Key words flood management; gap analysis; Metro Manila, Philippines; typhoon Ondoy -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 41-47. A framework for flood impact assessment in urban areas Michael J. HAMMOND1, Albert S. Chen1, David Butler1, Slobodan DjordjeviĆ1 & Natasa ManojloviĆ2 1 Centre for Water Systems, North Park Road, University of Exeter, Exeter EX4 4QF, UK m.j.hammond@exeter.ac.uk 2 Technical University of Hamburg-Harburg, Denickestraße 22 (I), 21073 Hamburg, Germany Abstract Urban flooding affects millions of people worldwide, and with urban populations projected to grow, this problem is likely to become more pressing in the future. Increasing urban flood resilience through the implementation of resilience strategies is a way to improve the management of flood risk. So that the effectiveness of various resilience strategies can be evaluated, it is vital that the impacts of flooding can be assessed in a comprehensive and consistent manner. To this end, a framework has been developed that will incorporate all the major impacts of floods. It has long been noted that the development of such a framework is fraught with difficulties, but it is necessary if we are to make progress in understanding the wider impacts of flooding. In this paper, the developing flood impact assessment framework is outlined, as well as laying out the principles that will underpin future research. Key words flood management; flood risk; impact assessment; flood resilience -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 48-56. Characteristics of flood disaster and evacuation activities of residents at Amami Oshima Island, Japan Akihiro Hashimoto, Akira tai, hideo oshikawa & Toshimitsu Komatsu Department of Urban and Environmental Engineering, Kyushu University, 819-0395, Japan ahashimo@civil.kyushu-u.ac.jp Abstract This paper describes the characteristics of the flood disaster and the evacuation activities of residents in the Sumiyo River basin in Amami Oshima Island, Kagoshima Prefecture, Japan, on 20 October 2010. A record-breaking rainfall amount was observed at the raingauge of the Sumiyo sub-office located in the southern part of Amami Oshima Island. The hourly precipitation exceeded 130 mm for the time period between 11:00 and 13:00 h on 20 October 2011. This torrential rain caused disasters such as flood inundation, landslides and debris flows all over Amami Oshima Island. There were three casualties, who were elderly people, in this heavy rainfall. A hearing investigation was carried out in the Sumiyo River basin in order to find out the reasons why the number of victims was low despite the record torrential rain. According to the hearing investigation, the local community worked so effectively that residents helped each other and urged themselves to evacuate in its early stage. Key words Amami Oshima Island, Japan; Sumiyo River, Japan; torrential rainfall; flood disaster; evacuation; local community -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 57-65. A comprehensive assessment of multilayered safety in flood risk management – the Dordrecht case study FRauke Hoss1, sebastiaan n. Jonkman1,3 & Bob Maaskant2 1 Delft University of Technology, Faculty of Civil Engineering and Geosciences, PB 5048, 2600GA Delft, The Netherlands fraukehoss@gmail.com 2 HKV Consultants, PB 2120, 8203 AC Lelystad, The Netherlands 3 Royal Haskoning, PB 8520, 3009 AM Rotterdam, The Netherlands Abstract In the year 2009, the concept of Multilayered Safety (MLS) was introduced in the Netherlands as a possible way to manage the flood risk. MLS consists of three layers: (1) Prevention (dikes, room for the river, etc.); (2) Spatial Solutions (flood-proofing houses, elevating houses, re-locating, etc.); and (3) Crisis Management (evacuation, warning, etc.). The main characteristic of MLS is the combination of probability- and loss-reducing measures. Combining measures can be technically tricky as it becomes more difficult to oversee the combined effect of those measures. Thus, in the first part of the study a framework was developed to gain insight into the combined effect of flood management measures of different types. MLS will only become a reality if it is more cost-efficient than the standard approach. This was investigated in the second part of the study. The Island of Dordrecht in the Netherlands was used as a case study. This area has about 120 000 inhabitants and is threatened by flooding from the North Sea and the River Waal, or a combination thereof. The cost-effectiveness of measures has been evaluated by comparing investment costs and the reduction in economic risk and risk of loss of life. As the cost-efficiency is found to be dependent on the initial safety level, it is concluded that in the Netherlands MLS only has the potential to supplement the existing flood protection. In areas with high levels of protection, as in Dordrecht, MLS is fit to add to, rather than replace, the prevailing prevention approach. However, MLS does introduce the option to better customize flood risk management to local circumstances. Additionally, this characteristic makes MLS an alternative where the prevention approach falls short of providing sufficient safety. Key words flood risk; flood risk management; multilayered safety; consequence-reducing measures; prevention; Dordrecht, The Netherlands -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 66-74. On the implementation of floodplain management plans on the Herbert and Johnstone rivers, Australia MARK Jempson1, BRUCE Leach2 & DAVID Trotter3 1 BMT WBM Pty Ltd, PO Box 604, Collins Street West, Victoria 8007, Australia mark.jempson@bmtwbm.com.au 2 Hinchinbrook Shire Council, PO Box 366, Ingham, Queensland 4850, Australia 3 Cassowary Coast Regional Council, PO Box 887, Innisfail, Queensland 4860, Australia Abstract: The Herbert and Johnstone river catchments are located in tropical North Queensland in Australia, and have catchment areas of approximately 10 000 km2 and 1600 km2, respectively. Their floodplains are predominantly utilised for agricultural purposes, but there are also many townships that are subject to frequent flooding. Floodplain management plans for both river systems were completed in 2003. Average annual damages (AAD) for the Lower Herbert River were estimated to be AUD$4.3 million, and for the Lower Johnstone River AUD$3.0 million. Floodplain management plans were developed to reduce the flood damages in urban areas, and to reduce the risk to human life. Many of the recommendations of the plans have now been implemented, and subsequently there have been several floods on both rivers. The implementation of the management plans and the effectiveness of the management measures are reviewed, and recommendations are made for consideration in the development of floodplain management plans. Key words flooding; floodplain management; flood risk; flood damage; levees; floodgates; Herbert River, Australia; Johnstone River, Australia; URBS, TUFLOW -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 75-85. The VNK2-project: a fully probabilistic risk analysis for all major levee systems in the Netherlands Ruben Jongejan1,2,3, Bob Maaskant1,3,5, Wouter ter Horst1,3,4, Fred HavingA1,5, Niels ROode1 & Harry STefess1 1 VNK2 Project Office, Rijkswaterstaat, PO Box 24094, 2526 LA, Utrecht, The Netherlands ruben.jongejan@rws.nl 2 Jongejan Risk Management Consulting, 2628DX, Delft, The Netherlands 3 Delft University of Technology, Hydraulic Engineering Section, PO Box 5048, 2628CN, Delft, The Netherlands 4 Infram, PO Box 16, 8316 ZG, Marknesse, The Netherlands 5 HKV Consultants, PO Box 2120, 8203 AC, Lelystad, The Netherlands Abstract Quantitative risk analysis is a powerful tool for assessing flood risks. The VNK2-project is a large-scale, fully probabilistic risk analysis for the low-lying parts of the Netherlands. It started in 2006 and draws upon decades of research and development. Flood probabilities are quantified in a Bayesian framework, taking into account the uncertainties related to loading conditions, the strength of flood defences, the outcomes of physical models, and the human factor. Economic and fatality risks are considered. These are expressed in various forms, ranging from population-averaged values to individual exposures. The project’s results can be used to evaluate alternatives for reducing risks, inform the political debate about new safety standards, prioritize interventions, and (re)direct research efforts to reduce important sources of uncertainty. Key words flood risk; VNK2; quantitative risk analysis -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 86-97. Optimal investment in emergency management in a multilayer flood risk framework B. Kolen1,2 & M. KOK1,3 1 HKV Consultants, PO Box 2010, 8203 AC Lelystad, The Netherlands b.kolen@hkv.nl; m.kok@hkv.nl 2 Radbout University Nijmegen, The Netherlands 3 Delft University of Technology, Faculty of Civil Engineering, Delft, The Netherlands Abstract Flood risk reduction can be obtained in many ways and by many measures. A common approach in the Netherlands is to divide the measures into three layers: flood prevention, land-use planning and emergency management. An important question is how to divide the investment between these layers. In this paper we follow an economic approach: the selection of measures is guided by minimising the total costs and maximising the benefits. It can be concluded that in the Dutch context, the main part of the investment is in flood prevention, but it is also optimal to spend a part of the budget (<5%) on emergency management. The smaller the optimal flooding probability, the smaller the part of the investment invested in emergency management. The method developed is based on a two-layer approach, but it can be extended by adding layers such as land-use planning. Key words flood risk management; cost benefit analysis; multi-layer safety Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 98-106. Long-term channel changes in the Mekong River: towards sustainable river channel management NAOKI MIYAZAWA Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, 4-3 Takeda, Kofu, 400-8511, Japan miyazawa@yamanashi.ac.jp Abstract A channel-evolution model for calculating long-term channel changes of a meandering river was developed using an existing fluid-dynamic model, and was applied to quantify channel changes of two meandering reaches in the Mekong River. The novel point of the present work is the linking of a state-of-the-art meandering planform evolution model with observed morphological changes within large-scale sand-bed rivers in tropical monsoon regions, which are highly dynamic systems, and assessment of the model performance. Unstable reaches of the Mekong River could be identified from Hydrographic Atlas GIS data in 1992 and 1993 and remotely sensed images taken in 2004 and 2005. The instability caused: (i) bank erosion and accretion of meander bends, and (ii) movement or development of bars and changes in the flow around the bars. The remote sensing measurements indicate that maximum erosion occurred downstream of the maximum curvature of the river-centre line in both reaches. The channel migration coefficients of the reaches were calibrated by comparing remote-sensing measurements and model simulations. The difference in the migration coefficients between both reaches was assumed to depend on the difference in bank height rather than the geotechnical properties of floodplain sediments. Applications for sustainable river channel management of the Mekong River are discussed. Key words channel change; Mekong River; river channel management; remote sensing; channel-evolution model -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 107-116. Risk assessment method for flood control planning considering global climate change in urban river management MASARU MORITA Shibaura Institute of Technology, 3-9-14 Toyosu, Koto-ku, Tokyo 135-8548, Japan morita@sic.shibaura-it.ac.jp Abstract This study presents a methodology for assessing flood risks, dealing in particular with decreased risk achieved by flood protection projects and increased risk due to climate change in a framework of flood risk management for urban rivers. “Flood risk” is defined as the product of flood damage potential and the probability of its occurrence. Flood inundations and their monetary damages are calculated with the Flood Damage Prediction Model (FDPM) using XP-SWMM. The increased cost of risk caused by climate change can be estimated from the difference between the potential damages before and after the predicted climate change using the Return Period Shift method. The change in risk cost is finally interpreted as a Flood Risk Impact Factor (FRIF) defined as the ratio of the change in risk cost to the present risk cost. The factor evaluates the changes in flood risk due to different causes using the same scale. Key words flood risk assessment; climate change; return period shift method; flood risk impact factor; urban river management -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 117-126. Risk sharing in practice for Integrated Flood Management MASAHIKO murase Takeo River Office, Ministry of Land, Infrastructure, Transport and Tourism (MLIT), 745 Showa, Takeo-cho, Takeo, Saga 843-0023, Japan KFA06115@nifty.com Abstract Under Integrated Flood Management (IFM), the flood risk management should be a combination of measures that address risk reduction, retention and transfer through a strategic mix of structural and non-structural measures for preparedness, response and recovery. Practical flood management depends on how to share the cost of taking the risk placed on society among governments, interested parties, communities and individuals. This study analyses the actual flood management in a local basin along the Rokkakugawa River, Japan, from the perspective of risk sharing. In this basin, the national government bore the costs for emergency recovery of 12 000 million yen after the 1980 flood and 30 000 million yen after the 1990 1/100-year flood, which can be considered as risk transfer. An annual budget has traditionally been allocated for risk reduction, but should include more risk retention towards residual risks. Community participation, through collaborative activities like mapping, contributes to risk sharing and implementation of IFM in actual situations. Key words risk sharing; flood management; IFM; community participation; Japan -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 127-134 Prediction of the effect of huge structures on eco-hydrological changes in Changjiang Basin TADANOBU NAKAYAMA1,2 & DAVID SHANKMAN3 1 National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan nakat@nies.go.jp 2 Centre for Ecology & Hydrology (CEH), Crowmarsh Gifford, Wallingford, Oxfordshire OX10 8BB, UK 3 Department of Geography, University of Alabama, Tuscaloosa, Alabama 35487-0322, USA Abstract Increasing frequency of severe floods on the middle and lower Changjiang (Yangtze) River during the past few decades is attributed to abnormal monsoon rainfall, various landscape changes and levee construction. Here, the process-based National Integrated Catchment-based Eco-hydrology (NICE) model was developed further for controlled discharge release at reservoirs to predict the impact of the Three-Gorges Dam (TGD) and South-to-North Water Transfer Project (SNWTP) on eco-hydrological changes. The model predicted that TGD might promote flood risk during the early summer monsoon (contrary to original justifications), and that morphological change over the long-term would promote the flood risk. This indicates the importance of managing both flood discharge and sediment deposition for the entire basin. Furthermore, time-integrated NDVI (TINDVI) estimated from satellite images during the past two decades showed generally decreasing trends beside the lakes, which indicates that the increase in lake reclamation and the resultant decrease in rice production were closely related to the hydrologic changes. Key words Changjiang River; eco-hydrology model; flood risk; South-to-North Water Transfer Project; Three-Gorges Dam -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 135-142 Educational activities for urban flood damage reduction using unique facilities Keiichi TODA1, TAISUKE ISHIGAKI2, YASUYUKI BABA3 & TAIRA OZAKI2 1 Disaster Prevention Research Institute, Kyoto University, Gokasho Uji-shi, Kyoto 611-0011, Japan toda.keiichi.4z@kyoto-u.ac.jp 2 Department of Civil, Environmental and Applied System Engineering, Kansai University, 3-3-35, Yamate-cho Suita-shi, Osaka 564-8680, Japan 3 Shirahama Oceanographic Observatory, Disaster Prevention Research Institute, Kyoto University, 2347-6, Katata, Shirahama-cho, Nishimuro-gun, Wakayama 649-2201, Japan Abstract We introduce our recent educational activities for urban flood damage reduction using a real-size model and a miniature model, and discuss their effects. In underground inundation by urban flooding, people must evacuate immediately via a staircase against a swift inflow, and people caught in basements must attempt to evacuate through doors held shut by hydrostatic pressure. In evacuation from underground spaces during flooding, it is very important to understand the critical conditions of evacuation via a staircase or by opening a door. We executed evacuation experiments using real-sized models. Low-lying streets are common sites of accidents with submerged cars and severe damage, including human damage, occasionally occurs under flooding conditions. Thus, we also executed evacuation experiments from a real-sized submerged car. We obtained the critical conditions for evacuation of inundated underground spaces and submerged cars. At the same time, we found that these experiments are very effective for education for urban flood damage reduction. People can feel how severe the flow is in a staircase, and how large the hydrostatic pressure exerted on a room door or a car door is. The experience of an evacuation experiment reminds them of the strength of water and importance of prompt evacuation. As the above evacuation experiments are very effective for enhancing disaster prevention awareness, we aim to help people to experience them during university events or educational activities. In addition, we made a miniature model of an urban area with a river, which can demonstrate urban inundation by river overflow and heavy rainfall using a small pump. The miniature model includes an underground space and an underground storage pond. The former part can express the flow configuration of underground inundation, and the latter part can show the good effects of underground storage. Not only children but also adults can learn about the urban flood mechanism and its countermeasures. Key words flood damage prevention; underground inundation; submerged car; evacuation experiments; education activities for disaster prevention -------------------------------------------------------------------------------------------------------------------------------------- Floods: From Risk to Opportunity (IAHS Publ. 357, 2013), 143-150 Download 369.75 Kb. Share with your friends:
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