Constrction of watershed flood disastermanagement information system and its application to the catastrophic flood of theYangtze River in 1998

This paper introduces a general method of establishing Watershed Flooding Disaster Management Information System (WFDMIS). The functions, database, models, user interface, software and hardware are considered. An application example in Poyang Lake Basin was given.

A Systematic Analysis of Systems Approach and Flood Risk Management Research:Trends,Gaps,and Opportunities

Flooding is a global threat,necessitating a comprehensive management approach.Due to the complexity of managing flood hazards and risks,researchers have advocated for holistic,comprehensive,and integrated approaches.This study,employing a systems thinking perspective,assessed global flood risk management research trends,gaps,and opportunities using132 published documents in BibTeX format.A systematic review of downloaded documents from the Scopus and Web of Science databases revealed slow progress of approximately 11.61% annual growth in applying systems thinking and its concomitant approaches to understanding global flood risk management over the past two decades compared to other fields like water resource management and business management systems.A significant gap exists in the application of systems thinking methodologies to flood risk management research between developed and developing countries,particularly in Africa,highlighting the urgency of reoriented research and policy efforts.The application gaps of the study methodology are linked to challenges outlined in existing literature,such as issues related to technical expertise and resource constraints.This study advocates a shift from linear to holistic approaches in flood risk management,aligned with the Sendai Framework for Disaster Risk Reduction 2015-2023 and the Sustainable Development Goals.Collaboration among researchers,institutions,and countries is essential to address this global challenge effectively.

Community Based Flood Risk Management: Local Knowledge and Actor’s Involvement Approach from Lower Karnali River Basin of Nepal

Connecting to the disaster risk reduction (DRR) studies, community-based initiatives are found to be more effective in both developed and developing countries, with a specific focus on the empowerment of local communities to build resilience. Building on social capital theory, the paper investigates on local knowledge (LK) practices experienced by the actors in an emerging economy using the community-based flood risk management (CB-FRM) approach. The qualitative research method was used by collecting data from focused group discussions, and interviews with the key informants including actors from local governments and non-government organizations. Additionally, informal discussions, field visits, and desk studies were undertaken to support the findings. The findings reveal that the local communities carry out various local knowledge experiences to respond during disaster management phases. They own a creative set of approaches based on the LK and that empowers them to live in the flood-prone areas, accepting the paradigm shift from fighting with floods to living with that. The local actor’s involvement is recognized as an essential component for CB-FRM activities. Yet, their program’s implementation is more oriented towards humanitarian assistance in emergency responses. Even, they often overlook the role of LK. Additionally, the results show a high level of presence of local communities during the preparedness and recovery phases, while NGOs and local governments have a medium role in preparedness and low in recovery phase. The lack of local ownership has also emerged as the major challenge. The research provides valuable insights for integrated CB-FRM policies by adopting to LK practices.

Integrated Coastal Flood Risk Management as a Means to Build Resilient Communities

There is a clear trend in the increase of damages and loss of lives and livelihoods in coastal areas as a result of rapid increase in coastal populations, and overall socio-economic development in coastal regions resulting in an increase in vulnerability of populations exposed to coastal floods and exposed infrastructure. Coastal flooding as a result of i.e. storm surges are difficult to predict and cannot be prevented, however there are means to apply integrated flood risk management approaches aiming to reduce the impact of coastal floods. A measure of the effectiveness of such approaches is the awareness and response of coastal communities to coastal flood risks. The paper introduces best practices and methods to lower coastal flood risk at the level of provinces, districts and the community level. This includes advances in coastal flood forecasting and early warning practices, improvement of institutional preparedness and integrated flood management practices as well as measures at the community level aiming to strengthen their resilience to coastal floods. The paper provides a showcase for the historical development and achievements to pave ways for the eventual implementation of a pilot project on integrated flood risk management in coastal areas in central Viet Nam.

Evaluation of the post-fire erosion and flood control works in the area of Cassandra(Chalkidiki, North Greece)

We quantified morphological and hydrographical characteristics of two drainage basins（Chanioti and N. Skioni） on Cassandra peninsula of Chalkidiki（North Greece）, and evaluated the effectiveness of post-fire flood and erosion control works. The drainage basins were chosen because of their severe damage by fire, post-fire potential for erosion and flood due to the steep relief, and the importance of the area for residential and tourism development. The first measures taken in the area after the fire were salvage cutting of burned trees, a total ban on grazing, and construction of three types of works, log erosion barriers（LEBs）, log check dams and contour branch barriers. Almost all necessary post-fire works were completed in both catchments but many construction failures were recorded. Approximately 75 % of the LEBs and45 % of the contour branch barriers functioned properly,while the remainder failed. Nearly 80 % of the log dams were sedimented to 0–20 % of the dam height, 14.3 %were 20–40 % filled and 5.9 % collapsed. Despite these failures, peak discharge declined by 10.5 % in Chanioti and 20.4 % in N. Skioni catchment. The main reasons for works failures were the rush of construction and the limited supervision of workers, which resulted in floods during the years that followed.

Floodplain Mapping and Risks Assessment of the Orashi River Using Re­mote Sensing and GIS in the Niger Delta Region, Nigeria

Residents along the shoreline of the Orashi River have yearly been dis­placed and recorded loss of lives,farmland,and infrastructures.The Gov­ernment’s approach has been the provision of relief materials to the victims instead of implementing adequate control measures.This research employs Shuttle Radar Topographic Mission and Google Earth imagery in devel­oping a 3D floodplain map using ArcGIS software.The result indicates the drainage system in the study area is dendritic with catchment of 79 subbasins and 76 pour point implying the area is floodplain.Incorporating the 3D slope which reveals that>8 and<8 makes up 1.15%and 98.85%of the study area respectively confirms the area is a floodplain.Aspect indicate west-facing slope are dark blue,3D hillshade indicate yellow is very low area and the high area is pink and also the buffer analysis result reveals wa­terbodies reflecting blue with an estimated area of 1.88 km2,yellow indicate 0.79 km2 of the shoreline,red indicate 0.81 km2 of the minor floodplain and pink contain 0.82 km2 with the length of 32.82 km.The result from google earth image in 2007 indicate absent of settlement,2013 indicate minimal settlement and 2020 indicate major settlement in the study area when cor­related with 3D Floodplain mapping before and during the flood in other to analyze and manage flooding for further purpose and the majority of the area are under seize with flood like in 2020.Therefore,Remote Sensing and GIS techniques are useful for Floodplain mapping,risk analysis for control measures for better flood management.

How to Achieve Local Resilience to Flood Risks by Increasing Solidarity: The Example of the “Syndicat Mixte” (Inter-Municipal Cooperation Structure) of the French Territory of Belfort-Montbéliard

This paper illustrates approaches to flooding risk governance in a territory where a high density of population corresponds to a high level of industrial activities and a significant development of transport infrastructures in a transboundary context between France, Germany and Switzerland. In the last few years, some fundamental changes in European official instructions about risks and especially about flooding risks occurred. Substantial public policy challenges remain in order to promote a broad-based resilient territory twinned with local knowledge of sustainable land management and civic participation in local governance. The survey is based on a GIS study and questionnaires with a representative panel of 235 stakeholders from the studied territory. Our statistical results demonstrate that, in spite of a deep-rooted mindset as regards flooding hazards, local population awareness of the territorial vulnerability is not related to important challenges. A hierarchical analysis of the data shows that the awareness of stakeholders is less related to the importance of risks when the territorial level decreases. It also highlights the decline of solidarity among neighbouring communities when the distance from the industrial axis increases. Greatly impacted by flooding risks, industrial activities of the regional basin are paradoxically not really perceived as common challenges. Such a case study illustrates how public policies need to be relevant to the adapted levels. Awareness of common issues is a central target to develop acceptance in order to provide an efficient framework of resilience, including willingness to pay to reduce the risk and solidarity in local development compensations.

Fast clogging problem of open check dams and a new type suggestion:curved footed type open check dam

Driftwood is one of the important physical components in mountainous rivers which causes severe hazards due to the clogging of bridges,culverts,and narrow sections during floods.Therefore,the understanding of driftwood dynamics and mitigation measures are crucial for managing wood in rivers.Open check dams are the most commonly used engineering measure for preventing driftwood from reaching downstream areas.Nevertheless,these open check dams frequently lose their sediment transport function when they are blocked by sediment and driftwood,especially during major flood events.This paper proposes a new type of open check dam for preventing from clogging.Thus,flume experiments were conducted to examine the influence of different types of open check dams on the characteristics of driftwood deposition.For the model with wood length(LWD)=16.5 cm,wood diameter(D)=15 mm,and wood number(N)=172,the highest trapping efficiency was observed with 90.1%and 87.2%retention rates for the classical debris flow breaker and curved footed open check dams,respectively.Laboratory tests showed that through this proposed design,woody debris blockage in a very short time was prevented from the accumulation of woods beside the dam.In addition to this,most of the sediment passed through the check dam and most of the driftwood got trapped.It can be briefly stated that the geometrical design of the structure plays an important role and can be chosen carefully to optimize trapping efficiency.By designing this type of open check dams in mountain river basins,it may provide a better understanding of the driftwood accumulation and basis for the optimal design of these structures.Further development of the solution proposed in this work can pave the way for designing different types of open check dams for effective flood management.

Cost-Benefit Analysis of the Wuxikou Integrated Flood Management Project Considering the Effects of Flood Risk Reduction and Resettlement

Evaluation of the economic costs and benefits of flood disaster risk management projects is crucial.However,current costbenefit analyses(CBA) often lack reliable estimates of the expected loss reduction from flood control measures and ignore quantitative assessments of resettlement.To address these limitations,this study incorporated a probabilistic risk analysis method and quantitative resettlement benefits assessment into the CBA framework,using the Wuxikou Integrated Flood Management Project(WIFMP) in Jiangxi Province,China,as a case study.The direct economic benefits of flood control were estimated by integrating hydrological statistics,numerical flood inundation simulation,and quantitative damage analysis with exposure and vulnerability data.Furthermore,the resettlement benefits were quantified by measuring the annual income growth of migrants based on assumptions about household employment.Our analysis shows that the total WIFMP investment is RMB 3546.1 million yuan(USD 1=RMB 6.976 yuan),including loan principal and interest of 244.4 million yuan,and operations and maintenance of 605.5 million yuan at 2020 prices.Annual project benefits are estimated at 351.3 million yuan in flood risk reduction,155.7-191.9 million yuan from increased resettlement income,and 42.7 million yuan in power and water revenues.Considering the costs and benefits across the entire project lifecycle,the internal rate of return ranges from 13.7 to 14.2%,and the net present value ranges from 31.8 to 352.6 billion yuan.Through improved benefit estimation methodology,this research enables a more reliable and holistic evaluation of costs and benefits for flood risk management projects.It provides insights for policymakers and practitioners involved in similar projects,contributing to more informed decision making and better allocation of resources in flood disaster risk management.

Developing Blue Spots Model for Tennessee Using GIS, and Advanced Data Analytics: Literature Review

Climate change and global warming results in natural hazards, including flash floods. Flash floods can create blue spots;areas where transport networks (roads, tunnels, bridges, passageways) and other engineering structures within them are at flood risk. The economic and social impact of flooding revealed that the damage caused by flash floods leading to blue spots is very high in terms of dollar amount and direct impacts on people’s lives. The impact of flooding within blue spots is either infrastructural or social, affecting lives and properties. Currently, more than 16.1 million properties in the U.S are vulnerable to flooding, and this is projected to increase by 3.2% within the next 30 years. Some models have been developed for flood risks analysis and management including some hydrological models, algorithms and machine learning and geospatial models. The models and methods reviewed are based on location data collection, statistical analysis and computation, and visualization (mapping). This research aims to create blue spots model for the State of Tennessee using ArcGIS visual programming language (model) and data analytics pipeline.

Dam Failures in the 20th Century： Nearly 1,000 Avoidable Victims in Italy Alone

The frequency of large dam failures all over the world, with a high toll of lives lost, pinpoints the still unsolved problems of flood risk resulting from the presence of large dams in built-up areas. Some of these failures and other related incidents took place in Italy in the past century. The purpose of this paper is to discuss the three worst cases of dam failures occurring in Italy, analyzing the causes which led to collapse. They are the dams of Gleno （1923）, Molare （1935） and Stava （1985）.

Event-driven flood management:design and computational modules

Flood management is a set of activities that have to be carried out in collaboration with multiple agencies.Advanced flood information with early warning generated using remote sensing satellite technologies can help the agencies to effectively manage the situation on ground.Various environmental parameters and forecasts provided by different agencies can be analyzed and compared with historical flood events for generating probable flood event alerts.The information(environmental parameters)provided by the agencies are heterogeneous and noncompliant to standards and distributed in nature.Synchronization of data from distributed resources and automation of data analysis process for flood management is a primary prerequisite for faster and efficient decision-making.Web 2.0-based web services enable data creation,sharing,communication,and collaboration on web.Spatial data sharing on web 2.0 for making quality of service using open-source software for efficient flood management is a challenge.Available software architectures proposed for risk and environmental crisis management are too generic in nature and needs lot of modification for flood management.An event-driven model coupled with data standardization procedures using service-oriented architecture provides an effective framework for flood management.In this paper,a framework capable of collecting heterogeneous distributed flood-related information for analyzing and alerting probable flood events is proposed.The framework has been implemented to generate automatic flood extent maps,by analyzing the distributed satellite data(as service).The automation of flood delineation process reduces the overall flood product generation time.Open-source web tools have been utilized in development of spatial information system to visualize and analyze the actual situation on ground facilitating overall decision-making process.

Mitigation of the amplitude and celerity of dam break shock wave using combination of groyne and vertical pier

This paper aims to numerically investigate the impact of the combination of groynes and vertical piers on mitigating the amplitude and celerity of dam break wave-front.First,a robust numerical model based on the Finite Volume Method(FVM)with the Harten,Lax and van Leer(HLL)approximate Reimann’s solver’s technique is developed and validated with other research studies.Then many different scenarios including group of piers,group of groynes with different shapes and combination of groynes and piers are considered for dam break flow modeling.The final results showed that group of piers alone or group of groynes alone have no significant effects on the wave-front depth and celerity but,combination of L-head groyne with piers can decrease the amplitude and celerity of the dam break wavefront or flood wave.In this case,a blockage zone between the groynes and intensive backwater effects behind them were observed.

Barriers to Insurance as a Flood Risk Management Tool:Evidence from a Survey of Property Owners

By using risk-adjusted price signals to transfer responsibility for property-level flood protection and recovery from governments to property owners,flood insurance represents a key tenet of the flood risk management(FRM)paradigm.The Government of Canada has worked with insurers to introduce flood insurance for the first time as a part of a broader shift towards FRM to limit the growing costs of flooding.The viability of flood insurance in Canada,however,has been questioned by research that disputes the utility of purchasing coverage by property owners.This study tested this assumption by drawing on public opinion survey data to assess factors that influence decisions about the utility of insurance.The findings reveal that Canadians have limited knowledge of flood insurance coverage,exhibit a low willingness-to-pay for both insurance and property-level flood protection measures,and expect governments to shoulder much of the financial burden of flood recovery through disaster assistance.

A Community Resilience Evaluation and Optimization Strategy based on Stormwater Management

In the context of disaster normalization,the concept of“resilience”has been gradually introduced into the field of disaster prevention and mitigation in urban communities.In order to resist the increasingly frequent disasters caused by extreme weather,it is necessary to shift the focus of building resilient urban communities to the level of stormwater management.Community resilience is a disaster prevention and mitigation capability based on community resources.In order to solve the deficiency of storm and flood management in the current construction of resilient communities in China,it is necessary to establish a quantitative evaluation system to evaluate it.This paper uses the analytic hierarchy process and Delphi method to establish a community resilience evaluation system from the perspectives of community material space level,community management level and individual level.Then three communities in Hefei City,Anhui Province are selected for practical application of the system,and corresponding optimization and transformation strategies are proposed.The results show that:(1)The resilience of community stormwater management is closely related to the integrated environment of the community,the allocation of flood control facilities and the daily disaster prevention and mitigation management;(2)The ability of disaster prevention and mitigation and the awareness of public participation of the residents in all communities are relatively weak,and the communities invest less in the popularization of stormwater management wisdom;and(3)Resilient communities should not only pay attention to the construction of non-engineering disaster prevention measures,but also to the application of small-scale green infrastructure oriented toward stormwater management.

Urban flood inundation and damage assessment based on numerical simulations of design rainstorms with different characteristics

In the context of global climate change and urbanization,urban flooding is an important type of natural disaster that affects urban development,especially in China,which is experiencing rapid urbanization.In the past 10 years,urban flooding events have caused huge disaster losses in Chinese cities.This has resulted in significant negative effects on the urban infrastructure,socioeconomic systems,and urban residents,thus causing widespread concern.Studies have confirmed the change in extreme rainstorms is due to the changing environments in many cities globally.Conducting studies on the impact of these rainstorms with different characteristics for urban flooding is valuable for coping with unfavorable situations.In addition,numerical simulations provide an economical and viable means to perform these studies.This paper presents a numerical model of Xiamen Island in China.Simulations were conducted for 12 design rainstorm events with different return periods,rain patterns,and durations.The results indicate that,in the case of an equal rainfall amount,the rainfall intensity is the key factor that affects the inundated area,depth,and damages.However,the rainfall intensity is not the only determining factor;the rainfall pattern also affects the inundations.In regard to the rainfall pattern,a higher rainfall peak coefficient usually leads to severe urban inundation and damage.As a result,the lag time would be shorter,which may further exacerbate the impact of urban flood disasters.The results of this study provide insights into managing flood risks,developing urban flood prevention strategies,and designing flood prevention measures.

Closing the Gaps in Disaster Management and Response:Drawing on Local Experiences with Cyclone Idai in Chimanimani,Zimbabwe

Cyclone Idai in Zimbabwe exposed deficiencies in the country's disaster management system.This study uses a phenomenological case exploration of the experiences of local residents in Rusitu Valley following cyclone-induced floods that affected the area in March 2019.Through capturing narratives of participants who were recruited through chain referrals,the research intends to understand how local actors,utilizing their local-based response systems,managed to fill in the voids that characterize disaster management practice in Zimbabwe.Results show that the participation of local"heroes"and"Samaritans,"by deploying their social networks,norms,relationships,practices,and modest ingenuity,helped to speed up response times and minimize threats to lives and livelihoods.Documentation of the stories of local actors about their disaster experiences also gives a richer picture of the Cyclone Idai disaster.Although the community response system also facilitated the operation of external disaster management agencies,their premature withdrawal tended to weaken the trust and values existing in the area,and created tensions between the disaster-affected people and other villagers.Given the delays in formal responses by the government and other external relief agencies,the practices of local actors,although spontaneous and largely uncoordinated,offer rich insights into the design and development of disaster management regimes.

Decision Making for Managing Community Flood Risks:Perspectives of United States Floodplain Managers

To reduce flood losses,floodplain managers make decisions on how to effectively manage their community’s flood risks.While there is a growing body of research that examines how individuals and households make decisions to manage their flood risks,far less attention has been directed at understanding the decision-making processes for flood management at the community level.This study aimed to narrow this research gap by examining floodplain managers’perceptions of the quality of their community’s flood management decision-making processes.Data gathered from interviews with 200 floodplain managers in the United States indicate that most floodplain managers perceive their community’s flood management decision-making processes to be good.The results also indicate that communities participating in the Federal Emergency Management Agency’s Community Rating System,as well as communities with a higher level of concern for flooding and a lower poverty rate,are significantly more likely to report better flood management decision-making processes.

Barriers and Drivers for Mainstreaming Nature-Based Solutions for Flood Risks: The Case of South Korea

Nature-based solutions(NBS)are seen as a promising adaptation measure that sustainably deals with diverse societal challenges,while simultaneously delivering multiple benefits.Nature-based solutions have been highlighted as a resilient and sustainable means of mitigating floods and other hazards globally.This study examined diverging conceptualizations of NBS,as well as the attitudinal(for example,emotions and beliefs)and contextual(for example,legal and political aspects)barriers and drivers of NBS for flood risks in South Korea.Semistructured interviews were conducted with 11 experts and focused on the topic of flood risk measures and NBS case studies.The analysis found 11 barriers and five drivers in the attitudinal domain,and 13 barriers and two drivers in the contextual domain.Most experts see direct monetary benefits as an important attitudinal factor for the public.Meanwhile,the cost-effectiveness of NBS and their capacity to cope with flood risks were deemed influential factors that could lead decision makers to opt for NBS.Among the contextual factors,insufficient systems to integrate NBS in practice and the ideologicalization of NBS policy were found to be peculiar barriers,which hinder consistent realization of initiatives and a long-term national plan for NBS.Understanding the barriers and drivers related to the mainstreaming of NBS is critical if we are to make the most of such solutions for society and nature.It is also essential that we have a shared definition,expectation,and vision of NBS.

The impact of flooding on Nigeria’s sustainable development goals(SDGs)

Nigeria has Africa’s biggest economy and a population of over 200 million people.Nigeria faces numerous challenges as it struggles to achieve the Sustainable Development Goals(SDGs)with flooding being the most serious with wide-reaching impacts.This paper highlights the impact flooding has on Nigeria reaching SDGs and enumerates the specific SDGs most directly impacted.A systematic literature review provides an overview of the relationship between flooding in Nigeria and the SDGs.It highlights the main causes of Nigeria’s flooding problem are man-made and advocates spatial planning as a suitable Flood Risk Management(FRM)strategy for the Nigerian environment.The paper calls for collaborative action by all concerned stakeholders to address the flooding problem and to help move Nigeria closer to meeting the United Nations(UN)2030 SDGs.Most importantly,the evidence presented in this paper seeks to promote action on a national scale to combat the flooding in Nigeria and help the nation work more effectively toward achieving the SDGs.