Development of flood index by characterisation of flood hydrographs

Science.gov (United States)

Bhattacharya, Biswa; Suman, Asadusjjaman

2015-04-01

In recent years the world has experienced deaths, large-scale displacement of people, billions of Euros of economic damage, mental stress and ecosystem impacts due to flooding. Global changes (climate change, population and economic growth, and urbanisation) are exacerbating the severity of flooding. The 2010 floods in Pakistan and the 2011 floods in Australia and Thailand demonstrate the need for concerted action in the face of global societal and environmental changes to strengthen resilience against flooding. Due to climatological characteristics there are catchments where flood forecasting may have a relatively limited role and flood event management may have to be trusted upon. For example, in flash flood catchments, which often may be tiny and un-gauged, flood event management often depends on approximate prediction tools such as flash flood guidance (FFG). There are catchments fed largely by flood waters coming from upstream catchments, which are un-gauged or due to data sharing issues in transboundary catchments the flow of information from upstream catchment is limited. Hydrological and hydraulic modelling of these downstream catchments will never be sufficient to provide any required forecasting lead time and alternative tools to support flood event management will be required. In FFG, or similar approaches, the primary motif is to provide guidance by synthesising the historical data. We follow a similar approach to characterise past flood hydrographs to determine a flood index (FI), which varies in space and time with flood magnitude and its propagation. By studying the variation of the index the pockets of high flood risk, requiring attention, can be earmarked beforehand. This approach can be very useful in flood risk management of catchments where information about hydro-meteorological variables is inadequate for any forecasting system. This paper presents the development of FI and its application to several catchments including in Kentucky in the USA

A high-resolution global flood hazard model

Science.gov (United States)

Sampson, Christopher C.; Smith, Andrew M.; Bates, Paul B.; Neal, Jeffrey C.; Alfieri, Lorenzo; Freer, Jim E.

2015-09-01

Floods are a natural hazard that affect communities worldwide, but to date the vast majority of flood hazard research and mapping has been undertaken by wealthy developed nations. As populations and economies have grown across the developing world, so too has demand from governments, businesses, and NGOs for modeled flood hazard data in these data-scarce regions. We identify six key challenges faced when developing a flood hazard model that can be applied globally and present a framework methodology that leverages recent cross-disciplinary advances to tackle each challenge. The model produces return period flood hazard maps at ˜90 m resolution for the whole terrestrial land surface between 56°S and 60°N, and results are validated against high-resolution government flood hazard data sets from the UK and Canada. The global model is shown to capture between two thirds and three quarters of the area determined to be at risk in the benchmark data without generating excessive false positive predictions. When aggregated to ˜1 km, mean absolute error in flooded fraction falls to ˜5%. The full complexity global model contains an automatically parameterized subgrid channel network, and comparison to both a simplified 2-D only variant and an independently developed pan-European model shows the explicit inclusion of channels to be a critical contributor to improved model performance. While careful processing of existing global terrain data sets enables reasonable model performance in urban areas, adoption of forthcoming next-generation global terrain data sets will offer the best prospect for a step-change improvement in model performance.

National Flood Hazard Layer (NFHL)

Data.gov (United States)

Federal Emergency Management Agency, Department of Homeland Security — The National Flood Hazard Layer (NFHL) is a compilation of GIS data that comprises a nationwide digital Flood Insurance Rate Map. The GIS data and services are...

Reserve Special Flood Hazard Areas (SFHA)

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This vector dataset depicts the 1% annual flood boundary (otherwise known as special flood hazard area or 100 year flood boundary) for its specified area. The data...

Modeling Compound Flood Hazards in Coastal Embayments

Science.gov (United States)

Moftakhari, H.; Schubert, J. E.; AghaKouchak, A.; Luke, A.; Matthew, R.; Sanders, B. F.

2017-12-01

Coastal cities around the world are built on lowland topography adjacent to coastal embayments and river estuaries, where multiple factors threaten increasing flood hazards (e.g. sea level rise and river flooding). Quantitative risk assessment is required for administration of flood insurance programs and the design of cost-effective flood risk reduction measures. This demands a characterization of extreme water levels such as 100 and 500 year return period events. Furthermore, hydrodynamic flood models are routinely used to characterize localized flood level intensities (i.e., local depth and velocity) based on boundary forcing sampled from extreme value distributions. For example, extreme flood discharges in the U.S. are estimated from measured flood peaks using the Log-Pearson Type III distribution. However, configuring hydrodynamic models for coastal embayments is challenging because of compound extreme flood events: events caused by a combination of extreme sea levels, extreme river discharges, and possibly other factors such as extreme waves and precipitation causing pluvial flooding in urban developments. Here, we present an approach for flood risk assessment that coordinates multivariate extreme analysis with hydrodynamic modeling of coastal embayments. First, we evaluate the significance of correlation structure between terrestrial freshwater inflow and oceanic variables; second, this correlation structure is described using copula functions in unit joint probability domain; and third, we choose a series of compound design scenarios for hydrodynamic modeling based on their occurrence likelihood. The design scenarios include the most likely compound event (with the highest joint probability density), preferred marginal scenario and reproduced time series of ensembles based on Monte Carlo sampling of bivariate hazard domain. The comparison between resulting extreme water dynamics under the compound hazard scenarios explained above provides an insight to the

77 FR 59675 - Compliance With Information Request, Flooding Hazard Reevaluation

Science.gov (United States)

2012-09-28

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0222] Compliance With Information Request, Flooding Hazard... was needed in the areas of seismic and flooding design, and emergency preparedness. In addition to... licensees reevaluate flooding hazards at nuclear power plant sites using updated flooding hazard information...

Flood Hazard Management: British and International Perspectives

Science.gov (United States)

James, L. Douglas

This proceedings of an international workshop at the Flood Hazard Research Centre (Queensway, Enfield, Middlesex, U.K.) begins by noting how past British research on flood problems concentrated on refining techniques to implement established policy. In contrast, research covered in North American and Australian publications involved normative issues on policy alternatives and administrative implementation. The workshop's participants included 16 widely recognized scientists, whose origins were about equally divided between Britain and overseas; from this group the workshop's organizers expertly drew ideas for refining British urban riverine flood hazard management and for cultivating links among researchers everywhere. Such intellectual exchange should be of keen interest to flood hazard program managers around the world, to students of comparative institutional performance, to those who make policy on protecting people from hazards, and to hydrologists and other geophysicists who must communicate descriptive information for bureaucratic, political, and public decision- making.

Sustainability-Based Flood Hazard Mapping of the Swannanoa River Watershed

Directory of Open Access Journals (Sweden)

Ebrahim Ahmadisharaf

2017-09-01

Full Text Available An integrated framework is presented for sustainability-based flood hazard mapping of the Swannanoa River watershed in the state of North Carolina, U.S. The framework uses a hydrologic model for rainfall–runoff transformation, a two-dimensional unsteady hydraulic model flood simulation and a GIS-based multi-criteria decision-making technique for flood hazard mapping. Economic, social, and environmental flood hazards are taken into account. The importance of each hazard is quantified through a survey to the experts. Utilizing the proposed framework, sustainability-based flood hazard mapping is performed for the 100-year design event. As a result, the overall flood hazard is provided in each geographic location. The sensitivity of the overall hazard with respect to the weights of the three hazard components were also investigated. While the conventional flood management approach is to assess the environmental impacts of mitigation measures after a set of feasible options are selected, the presented framework incorporates the environmental impacts into the analysis concurrently with the economic and social influences. Thereby, it provides a more sustainable perspective of flood management and can greatly help the decision makers to make better-informed decisions by clearly understanding the impacts of flooding on economy, society and environment.

Flood Risk and Flood hazard maps - Visualisation of hydrological risks

International Nuclear Information System (INIS)

Spachinger, Karl; Dorner, Wolfgang; Metzka, Rudolf; Serrhini, Kamal; Fuchs, Sven

2008-01-01

Hydrological models are an important basis of flood forecasting and early warning systems. They provide significant data on hydrological risks. In combination with other modelling techniques, such as hydrodynamic models, they can be used to assess the extent and impact of hydrological events. The new European Flood Directive forces all member states to evaluate flood risk on a catchment scale, to compile maps of flood hazard and flood risk for prone areas, and to inform on a local level about these risks. Flood hazard and flood risk maps are important tools to communicate flood risk to different target groups. They provide compiled information to relevant public bodies such as water management authorities, municipalities, or civil protection agencies, but also to the broader public. For almost each section of a river basin, run-off and water levels can be defined based on the likelihood of annual recurrence, using a combination of hydrological and hydrodynamic models, supplemented by an analysis of historical records and mappings. In combination with data related to the vulnerability of a region risk maps can be derived. The project RISKCATCH addressed these issues of hydrological risk and vulnerability assessment focusing on the flood risk management process. Flood hazard maps and flood risk maps were compiled for Austrian and German test sites taking into account existing national and international guidelines. These maps were evaluated by eye-tracking using experimental graphic semiology. Sets of small-scale as well as large-scale risk maps were presented to test persons in order to (1) study reading behaviour as well as understanding and (2) deduce the most attractive components that are essential for target-oriented risk communication. A cognitive survey asking for negative and positive aspects and complexity of each single map complemented the experimental graphic semiology. The results indicate how risk maps can be improved to fit the needs of different user

Sept 2013 NFHL Flood Hazard Boundaries

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by FEMA, and any Letters Of Map Revision...

Elephant Butte Special Flood Hazard Areas (SFHA)

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This vector dataset depicts the 1% annual flood boundary (otherwise known as special flood hazard area or 100 year flood boundary) for its specified area. The data...

78 FR 24439 - Compliance With Information Request, Flooding Hazard Reevaluation

Science.gov (United States)

2013-04-25

... NUCLEAR REGULATORY COMMISSION [NRC-2013-0073] Compliance With Information Request, Flooding Hazard... Estimating Flooding Hazards due to Dam Failure.'' This draft JLD-ISG provides guidance acceptable to the NRC staff for reevaluating flooding hazards due to dam failure for the purpose of responding to enclosure 2...

Flood Hazard and Risk Analysis in Urban Area

Science.gov (United States)

Huang, Chen-Jia; Hsu, Ming-hsi; Teng, Wei-Hsien; Lin, Tsung-Hsien

2017-04-01

Typhoons always induce heavy rainfall during summer and autumn seasons in Taiwan. Extreme weather in recent years often causes severe flooding which result in serious losses of life and property. With the rapid industrial and commercial development, people care about not only the quality of life, but also the safety of life and property. So the impact of life and property due to disaster is the most serious problem concerned by the residents. For the mitigation of the disaster impact, the flood hazard and risk analysis play an important role for the disaster prevention and mitigation. In this study, the vulnerability of Kaohsiung city was evaluated by statistics of social development factor. The hazard factors of Kaohsiung city was calculated by simulated flood depth of six different return periods and four typhoon events which result in serious flooding in Kaohsiung city. The flood risk can be obtained by means of the flood hazard and social vulnerability. The analysis results provide authority to strengthen disaster preparedness and to set up more resources in high risk areas.

Characterising Record Flooding in the United Kingdom

Science.gov (United States)

Cox, A.; Bates, P. D.; Smith, J. A.

2017-12-01

Though the most notable floods in history have been carefully explained, there remains a lack of literature that explores the nature of record floods as a whole in the United Kingdom. We characterise the seasonality, statistical and spatial distribution, and meteorological causes of peak river flows for 521 gauging stations spread across the British Isles. We use annual maximum data from the National River Flow Archive, catchment descriptors from the Flood Estimation Handbook, and historical records of large floods. What we aim to find is in what ways, if any, the record flood for a station is different from more 'typical' floods. For each station, we calculate two indices: the seasonal anomaly and the flood index. Broadly, the seasonal anomaly is the degree to which a station's record flood happens at a different time of year compared to typical floods at that site, whilst the flood index is a station's record flood discharge divided by the discharge of the 1-in-10-year return period event. We find that while annual maximum peaks are dominated by winter frontal rainfall, record floods are disproportionately caused by summer convective rainfall. This analysis also shows that the larger the seasonal anomaly, the higher the flood index. Additionally, stations across the country have record floods that occur in the summer with no notable spatial pattern, yet the most seasonally anomalous record events are concentrated around the south and west of the British Isles. Catchment descriptors tell us little about the flood index at a particular station, but generally areas with lower mean annual precipitation have a higher flood index. The inclusion of case studies from recent and historical examples of notable floods across the UK supplements our analysis and gives insight into how typical these events are, both statistically and meteorologically. Ultimately, record floods in general happen at relatively unexpected times and with unpredictable magnitudes, which is a

Truth or Consequences Special Flood Hazard Areas (SFHA)

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This vector dataset depicts the 1% annual flood boundary (otherwise known as special flood hazard area or 100 year flood boundary) for its specified area. The data...

77 FR 65417 - Compliance With Information Request, Flooding Hazard Reevaluation

Science.gov (United States)

2012-10-26

... NUCLEAR REGULATORY COMMISSION [NRC-2012-0261] Compliance With Information Request, Flooding Hazard... flooding hazard reanalysis in response to enclosure 2 of a March 12, 2012, information request. DATES... evaluation of whether further regulatory action was needed in the areas of seismic and flooding design, and...

Coastal Flood Hazard Composite Layer for the Coastal Flood Exposure Mapper

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is a map service for the Coastal Flood Hazard Composite dataset. This dataset was created by combining hazard zones from the following datasets: FEMA V zones,...

Flood Hazard Areas - High Risk

Data.gov (United States)

Department of Homeland Security — The S_Fld_Haz_Ar table contains information about the flood hazards within the study area. A spatial file with locational information also corresponds with this data...

Flood hazard mapping of Palembang City by using 2D model

Science.gov (United States)

Farid, Mohammad; Marlina, Ayu; Kusuma, Muhammad Syahril Badri

2017-11-01

Palembang as the capital city of South Sumatera Province is one of the metropolitan cities in Indonesia that flooded almost every year. Flood in the city is highly related to Musi River Basin. Based on Indonesia National Agency of Disaster Management (BNPB), the level of flood hazard is high. Many natural factors caused flood in the city such as high intensity of rainfall, inadequate drainage capacity, and also backwater flow due to spring tide. Furthermore, anthropogenic factors such as population increase, land cover/use change, and garbage problem make flood problem become worse. The objective of this study is to develop flood hazard map of Palembang City by using two dimensional model. HEC-RAS 5.0 is used as modelling tool which is verified with field observation data. There are 21 sub catchments of Musi River Basin in the flood simulation. The level of flood hazard refers to Head Regulation of BNPB number 2 in 2012 regarding general guideline of disaster risk assessment. The result for 25 year return per iod of flood shows that with 112.47 km2 area of inundation, 14 sub catchments are categorized in high hazard level. It is expected that the hazard map can be used for risk assessment.

Flood Impacts on People: from Hazard to Risk Maps

Science.gov (United States)

Arrighi, C.; Castelli, F.

2017-12-01

The mitigation of adverse consequences of floods on people is crucial for civil protection and public authorities. According to several studies, in the developed countries the majority of flood-related fatalities occurs due to inappropriate high risk behaviours such as driving and walking in floodwaters. In this work both the loss of stability of vehicles and pedestrians in floodwaters are analysed. Flood hazard is evaluated, based on (i) a 2D inundation model of an urban area, (ii) 3D hydrodynamic simulations of water flows around vehicles and human body and (iii) a dimensional analysis of experimental activity. Exposure and vulnerability of vehicles and population are assessed exploiting several sources of open GIS data in order to produce risk maps for a testing case study. The results show that a significant hazard to vehicles and pedestrians exists in the study area. Particularly high is the hazard to vehicles, which are likely to be swept away by flood flow, possibly aggravate damages to structures and infrastructures and locally alter the flood propagation. Exposure and vulnerability analysis identifies some structures such as schools and public facilities, which may attract several people. Moreover, some shopping facilities in the area, which attract both vehicular and pedestrians' circulation are located in the highest flood hazard zone.The application of the method demonstrates that, at municipal level, such risk maps can support civil defence strategies and education to active citizenship, thus contributing to flood impact reduction to population.

Assessment of Three Flood Hazard Mapping Methods: A Case Study of Perlis

Science.gov (United States)

Azizat, Nazirah; Omar, Wan Mohd Sabki Wan

2018-03-01

Flood is a common natural disaster and also affect the all state in Malaysia. Regarding to Drainage and Irrigation Department (DID) in 2007, about 29, 270 km2 or 9 percent of region of the country is prone to flooding. Flood can be such devastating catastrophic which can effected to people, economy and environment. Flood hazard mapping can be used is an important part in flood assessment to define those high risk area prone to flooding. The purposes of this study are to prepare a flood hazard mapping in Perlis and to evaluate flood hazard using frequency ratio, statistical index and Poisson method. The six factors affecting the occurrence of flood including elevation, distance from the drainage network, rainfall, soil texture, geology and erosion were created using ArcGIS 10.1 software. Flood location map in this study has been generated based on flooded area in year 2010 from DID. These parameters and flood location map were analysed to prepare flood hazard mapping in representing the probability of flood area. The results of the analysis were verified using flood location data in year 2013, 2014, 2015. The comparison result showed statistical index method is better in prediction of flood area rather than frequency ratio and Poisson method.

The spatial and temporal characterisation of flooding within the ...

African Journals Online (AJOL)

The inundated area of a wetland is characterised by annual and interannual variability. This paper presents remotely-sensed imagery in order to better understand the spatial and temporal patterns of flooding within the floodplain wetland of the Nyl River, Limpopo Province. A detailed understanding of the hydrological ...

Flood Hazards: Communicating Hydrology and Complexity to the Public

Science.gov (United States)

Holmes, R. R.; Blanchard, S. F.; Mason, R. R.

2010-12-01

Floods have a major impact on society and the environment. Since 1952, approximately 1,233 of 1,931 (64%) Federal disaster declarations were due directly to flooding, with an additional 297 due to hurricanes which had associated flooding. Although the overall average annual number of deaths due to flooding has decreased in the United States, the average annual flood damage is rising. According to the Munich Reinsurance Company in their publication “Schadenspiegel 3/2005”, during 1990s the world experienced as much as $500 billion in economic losses due to floods, highlighting the serious need for continued emphasis on flood-loss prevention measures. Flood-loss prevention has two major elements: mitigation (including structural flood-control measures and land-use planning and regulation) and risk awareness. Of the two, increasing risk awareness likely offers the most potential for protecting lives over the near-term and long-term sustainability in the coming years. Flood-risk awareness and risk-aware behavior is dependent on communication, involving both prescriptive and educational measures. Prescriptive measures (for example, flood warnings and stormwater ordinances) are and have been effective, but there is room for improvement. New communications technologies, particularly social media utilizing mobile, smart phones and text devices, for example, could play a significant role in increasing public awareness of long-term risk and near-term flood conditions. The U.S. Geological Survey (USGS), for example, the Federal agency that monitors the Nation’s rivers, recently released a new service that can better connect the to the public to information about flood hazards. The new service, WaterAlert (URL: http://water.usgs.gov/wateralert/), allows users to set flood notification thresholds of their own choosing for any USGS real-time streamgage. The system then sends emails or text messages to subscribers whenever the threshold conditions are met, as often as the

Determining the Financial Impact of Flood Hazards in Ungaged Basins

Science.gov (United States)

Cotterman, K. A.; Gutenson, J. L.; Pradhan, N. R.; Byrd, A.

2017-12-01

Many portions of the Earth lack adequate authoritative or in situ data that is of great value in determining natural hazard vulnerability from both anthropogenic and physical perspective. Such locations include the majority of developing nations, which do not possess adequate warning systems and protective infrastructure. The lack of warning and protection from natural hazards make these nations vulnerable to the destructive power of events such as floods. The goal of this research is to demonstrate an initial workflow with which to characterize flood financial hazards with global datasets and crowd-sourced, non-authoritative data in ungagged river basins. This workflow includes the hydrologic and hydraulic response of the watershed to precipitation, characterized by the physics-based modeling application Gridded Surface-Subsurface Hydrologic Analysis (GSSHA) model. In addition, data infrastructure and resources are available to approximate the human impact of flooding. Open source, volunteer geographic information (VGI) data can provide global coverage of elements at risk of flooding. Additional valuation mechanisms can then translate flood exposure into percentage and financial damage to each building. The combinations of these tools allow the authors to remotely assess flood hazards with minimal computational, temporal, and financial overhead. This combination of deterministic and stochastic modeling provides the means to quickly characterize watershed flood vulnerability and will allow emergency responders and planners to better understand the implications of flooding, both spatially and financially. In either a planning, real-time, or forecasting scenario, the system will assist the user in understanding basin flood vulnerability and increasing community resiliency and preparedness.

Forecasting surface water flooding hazard and impact in real-time

Science.gov (United States)

Cole, Steven J.; Moore, Robert J.; Wells, Steven C.

2016-04-01

Across the world, there is increasing demand for more robust and timely forecast and alert information on Surface Water Flooding (SWF). Within a UK context, the government Pitt Review into the Summer 2007 floods provided recommendations and impetus to improve the understanding of SWF risk for both off-line design and real-time forecasting and warning. Ongoing development and trial of an end-to-end real-time SWF system is being progressed through the recently formed Natural Hazards Partnership (NHP) with delivery to the Flood Forecasting Centre (FFC) providing coverage over England & Wales. The NHP is a unique forum that aims to deliver coordinated assessments, research and advice on natural hazards for governments and resilience communities across the UK. Within the NHP, a real-time Hazard Impact Model (HIM) framework has been developed that includes SWF as one of three hazards chosen for initial trialling. The trial SWF HIM system uses dynamic gridded surface-runoff estimates from the Grid-to-Grid (G2G) hydrological model to estimate the SWF hazard. National datasets on population, infrastructure, property and transport are available to assess impact severity for a given rarity of SWF hazard. Whilst the SWF hazard footprint is calculated in real-time using 1, 3 and 6 hour accumulations of G2G surface runoff on a 1 km grid, it has been possible to associate these with the effective rainfall design profiles (at 250m resolution) used as input to a detailed flood inundation model (JFlow+) run offline to produce hazard information resolved to 2m resolution. This information is contained in the updated Flood Map for Surface Water (uFMfSW) held by the Environment Agency. The national impact datasets can then be used with the uFMfSW SWF hazard dataset to assess impacts at this scale and severity levels of potential impact assigned at 1km and for aggregated county areas in real-time. The impact component is being led by the Health and Safety Laboratory (HSL) within the NHP

Flooding Hazards across Southern China and Prospective Sustainability Measures

Directory of Open Access Journals (Sweden)

Hai-Min Lyu

2018-05-01

Full Text Available The Yangtze River Basin and Huaihe River Basin in Southern China experienced severe floods 1998 and 2016. The reasons for the flooding hazards include the following two factors: hazardous weather conditions and degradation of the hydrological environment due to anthropogenic activities. This review work investigated the weather conditions based on recorded data, which showed that both 1998 and 2016 were in El Nino periods. Human activities include the degradations of rivers and lakes and the effects caused by the building of the Three Gorges Dam. In addition, the flooding in 2016 had a lower hazard scale than that in 1998 but resulted in larger economic losses than that of 1998. To mitigate urban waterlogging caused by flooding hazards, China proposed a new strategy named Spongy City (SPC in 2014. SPC promotes sustainable city development so that a city has the resilience to adapt to climate change, to mitigate the impacts of waterlogging caused by extreme rainfall events. The countermeasures used to tackle the SPC construction-related problems, such as local inundation, water resource shortage, storm water usage, and water pollution control, are proposed for city management to improve the environment.

Revision to flood hazard evaluation for the Savannah River Site

Energy Technology Data Exchange (ETDEWEB)

Buckley, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Werth, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2014-08-25

Requirements for the Natural Phenomena Hazard (NPH) mitigation for new and existing Department of Energy (DOE) facilities are outlined in DOE Order 420.1. This report examines the hazards posed by potential flooding and represents an update to two previous reports. The facility-specific probabilistic flood hazard curve is defined as the water elevation for each annual probability of precipitation occurrence (or inversely, the return period in years). New design hyetographs for both 6-hr and 24-hr precipitation distributions were used in conjunction with hydrological models of various basins within the Savannah River Site (SRS). For numerous locations of interest, peak flow discharge and flood water elevation were determined. In all cases, the probability of flooding of these facilities for a 100,000 year precipitation event is negligible.

Hydrology Analysis and Modelling for Klang River Basin Flood Hazard Map

Science.gov (United States)

Sidek, L. M.; Rostam, N. E.; Hidayah, B.; Roseli, ZA; Majid, W. H. A. W. A.; Zahari, N. Z.; Salleh, S. H. M.; Ahmad, R. D. R.; Ahmad, M. N.

2016-03-01

Flooding, a common environmental hazard worldwide has in recent times, increased as a result of climate change and urbanization with the effects felt more in developing countries. As a result, the explosive of flooding to Tenaga Nasional Berhad (TNB) substation is increased rapidly due to existing substations are located in flood prone area. By understanding the impact of flood to their substation, TNB has provided the non-structure mitigation with the integration of Flood Hazard Map with their substation. Hydrology analysis is the important part in providing runoff as the input for the hydraulic part.

Damaging Rainfall and Flooding. The Other Sahel Hazards

Energy Technology Data Exchange (ETDEWEB)

Tarhule, A. [Department of Geography, University of Oklahoma, 100 East Boyd Street, Norman, OK, 73079 (United States)

2005-10-01

Damaging rainfall and rain-induced flooding occur from time to time in the drought-prone Sahel savannah zone of Niger in West Africa but official records of these events and their socioeconomic impacts do not exist. This paper utilized newspaper accounts between 1970 and 2000 to survey and illustrate the range of these flood hazards in the Sahel. During the study interval, 53 newspaper articles reported 79 damaging rainfall and flood events in 47 different communities in the Sahel of Niger. Collectively, these events destroyed 5,580 houses and rendered 27,289 people homeless. Cash losses and damage to infrastructure in only three events exceeded $4 million. Sahel residents attribute these floods to five major causes including both natural and anthropogenic, but they view the flood problem as driven primarily by land use patterns. Despite such awareness, traditional coping strategies appear inadequate for dealing with the problems in part because of significant climatic variability. Analysis of several rainfall measures indicates that the cumulative rainfall in the days prior to a heavy rain event is an important factor influencing whether or not heavy rainfall results in flooding. Thus, despite some limitations, newspaper accounts of historical flooding are largely consistent with measured climatic variables. The study demonstrates that concerted effort is needed to improve the status of knowledge concerning flood impacts and indeed other natural and human hazards in the Sahel.

Global river flood hazard maps: hydraulic modelling methods and appropriate uses

Science.gov (United States)

Townend, Samuel; Smith, Helen; Molloy, James

2014-05-01

Flood hazard is not well understood or documented in many parts of the world. Consequently, the (re-)insurance sector now needs to better understand where the potential for considerable river flooding aligns with significant exposure. For example, international manufacturing companies are often attracted to countries with emerging economies, meaning that events such as the 2011 Thailand floods have resulted in many multinational businesses with assets in these regions incurring large, unexpected losses. This contribution addresses and critically evaluates the hydraulic methods employed to develop a consistent global scale set of river flood hazard maps, used to fill the knowledge gap outlined above. The basis of the modelling approach is an innovative, bespoke 1D/2D hydraulic model (RFlow) which has been used to model a global river network of over 5.3 million kilometres. Estimated flood peaks at each of these model nodes are determined using an empirically based rainfall-runoff approach linking design rainfall to design river flood magnitudes. The hydraulic model is used to determine extents and depths of floodplain inundation following river bank overflow. From this, deterministic flood hazard maps are calculated for several design return periods between 20-years and 1,500-years. Firstly, we will discuss the rationale behind the appropriate hydraulic modelling methods and inputs chosen to produce a consistent global scaled river flood hazard map. This will highlight how a model designed to work with global datasets can be more favourable for hydraulic modelling at the global scale and why using innovative techniques customised for broad scale use are preferable to modifying existing hydraulic models. Similarly, the advantages and disadvantages of both 1D and 2D modelling will be explored and balanced against the time, computer and human resources available, particularly when using a Digital Surface Model at 30m resolution. Finally, we will suggest some

Flood hazards in an urbanizing watershed in Riyadh, Saudi Arabia

Directory of Open Access Journals (Sweden)

Hatim O. Sharif

2016-03-01

Full Text Available Riyadh, the capital of the Kingdom of Saudi Arabia, has experienced unusual levels of urbanization in the past few decades, making it one of the fastest growing cities in the world. This paper examines flood hazards in the rapidly urbanizing catchment of Al-Aysen in Riyadh. Remote sensing and geographic information system techniques were employed to obtain and prepare input data for hydrologic and hydraulic models, with the former based on the very popular curve number approach. Due to the limited nature of the rainfall data, observations from two rain gauges in the vicinity of the catchment were used to estimate design storms. The hydrologic model was run in a semi-distributed mode by dividing the catchment into many sub-catchments. The impact of urbanization on run-off volume and peak discharge resulting from different storms was investigated, with various urbanization scenarios simulated. Flood hazard zones and affected streets were also identified through hydrologic/hydraulic model simulation. The mismatch between administrative and catchment boundaries can create problems in flood risk management for similar cities since hydrologic processes and flood hazards are based on the hydrologic connectivity. Since flooding events impact the road network and create driving hazards, governmental decision-makers must take the necessary precautions to protect drivers in these situations.

Flood hazard zoning in Yasooj region, Iran, using GIS and multi-criteria decision analysis

Directory of Open Access Journals (Sweden)

Omid Rahmati

2016-05-01

Full Text Available Flood is considered to be the most common natural disaster worldwide during the last decades. Flood hazard potential mapping is required for management and mitigation of flood. The present research was aimed to assess the efficiency of analytical hierarchical process (AHP to identify potential flood hazard zones by comparing with the results of a hydraulic model. Initially, four parameters via distance to river, land use, elevation and land slope were used in some part of the Yasooj River, Iran. In order to determine the weight of each effective factor, questionnaires of comparison ratings on the Saaty's scale were prepared and distributed to eight experts. The normalized weights of criteria/parameters were determined based on Saaty's nine-point scale and its importance in specifying flood hazard potential zones using the AHP and eigenvector methods. The set of criteria were integrated by weighted linear combination method using ArcGIS 10.2 software to generate flood hazard prediction map. The inundation simulation (extent and depth of flood was conducted using hydrodynamic program HEC-RAS for 50- and 100-year interval floods. The validation of the flood hazard prediction map was conducted based on flood extent and depth maps. The results showed that the AHP technique is promising of making accurate and reliable prediction for flood extent. Therefore, the AHP and geographic information system (GIS techniques are suggested for assessment of the flood hazard potential, specifically in no-data regions.

Stochastic Urban Pluvial Flood Hazard Maps Based upon a Spatial-Temporal Rainfall Generator

Directory of Open Access Journals (Sweden)

Nuno Eduardo Simões

2015-06-01

Full Text Available It is a common practice to assign the return period of a given storm event to the urban pluvial flood event that such storm generates. However, this approach may be inappropriate as rainfall events with the same return period can produce different urban pluvial flooding events, i.e., with different associated flood extent, water levels and return periods. This depends on the characteristics of the rainfall events, such as spatial variability, and on other characteristics of the sewer system and the catchment. To address this, the paper presents an innovative contribution to produce stochastic urban pluvial flood hazard maps. A stochastic rainfall generator for urban-scale applications was employed to generate an ensemble of spatially—and temporally—variable design storms with similar return period. These were used as input to the urban drainage model of a pilot urban catchment (~9 km2 located in London, UK. Stochastic flood hazard maps were generated through a frequency analysis of the flooding generated by the various storm events. The stochastic flood hazard maps obtained show that rainfall spatial-temporal variability is an important factor in the estimation of flood likelihood in urban areas. Moreover, as compared to the flood hazard maps obtained by using a single spatially-uniform storm event, the stochastic maps generated in this study provide a more comprehensive assessment of flood hazard which enables better informed flood risk management decisions.

Societal and economic impacts of flood hazards in Turkey – an overview

Directory of Open Access Journals (Sweden)

Koç Gamze

2016-01-01

Full Text Available Turkey has been severely affected by many natural hazards, in particular earthquakes and floods. Although there is a large body of literature on earthquake hazards and risks in Turkey, comparatively little is known about flood hazards and risks. Therefore, with this study it is aimed to investigate flood patterns, societal and economic impacts of flood hazards in Turkey, as well as providing a comparative overview of the temporal and spatial distribution of flood losses by analysing EM-DAT (Emergency Events Database and TABB (Turkey Disaster Data Base databases on disaster losses throughout Turkey for the years 1960-2014. The comparison of these two databases reveals big mismatches of the flood data, e.g. the reported number of events, number of affected people and economic loss, differ dramatically. With this paper, it has been explored reasons for mismatches. Biases and fallacies for loss data in the two databases has been discussed as well. Since loss data collection is gaining more and more attention, e.g. in the Sendai Framework for Disaster Risk Reduction 2015-2030 (SFDRR, the study could offer a base-work for developing guidelines and procedures on how to standardize loss databases and implement across the other hazard events, as well as substantial insights for flood risk mitigation and adaptation studies in Turkey and will offer valuable insights for other (European countries.

Fragility analysis of flood protection structures in earthquake and flood prone areas around Cologne, Germany for multi-hazard risk assessment

Science.gov (United States)

Tyagunov, Sergey; Vorogushyn, Sergiy; Munoz Jimenez, Cristina; Parolai, Stefano; Fleming, Kevin; Merz, Bruno; Zschau, Jochen

2013-04-01

The work presents a methodology for fragility analyses of fluvial earthen dikes in earthquake and flood prone areas. Fragility estimates are being integrated into the multi-hazard (earthquake-flood) risk analysis being undertaken within the framework of the EU FP7 project MATRIX (New Multi-Hazard and Multi-Risk Assessment Methods for Europe) for the city of Cologne, Germany. Scenarios of probable cascading events due to the earthquake-triggered failure of flood protection dikes and the subsequent inundation of surroundings are analyzed for the area between the gauges Andernach and Düsseldorf along the Rhine River. Along this river stretch, urban areas are partly protected by earthen dikes, which may be prone to failure during exceptional floods and/or earthquakes. The seismic fragility of the dikes is considered in terms of liquefaction potential (factor of safety), estimated by the use of the simplified procedure of Seed and Idriss. It is assumed that initiation of liquefaction at any point throughout the earthen dikes' body corresponds to the failure of the dike and, therefore, this should be taken into account for the flood risk calculations. The estimated damage potential of such structures is presented as a two-dimensional surface (as a function of seismic hazard and water level). Uncertainties in geometrical and geotechnical dike parameters are considered within the framework of Monte Carlo simulations. Taking into consideration the spatial configuration of the existing flood protection system within the area under consideration, seismic hazard curves (in terms of PGA) are calculated for sites along the river segment of interest at intervals of 1 km. The obtained estimates are used to calculate the flood risk when considering the temporal coincidence of seismic and flood events. Changes in flood risk for the considered hazard cascade scenarios are quantified and compared to the single-hazard scenarios.

Swiss Re Global Flood Hazard Zones: Know your flood risk

Science.gov (United States)

Vinukollu, R. K.; Castaldi, A.; Mehlhorn, J.

2012-12-01

Floods, among all natural disasters, have a great damage potential. On a global basis, there is strong evidence of increase in the number of people affected and economic losses due to floods. For example, global insured flood losses have increased by 12% every year since 1970 and this is expected to further increase with growing exposure in the high risk areas close to rivers and coastlines. Recently, the insurance industry has been surprised by the large extent of losses, because most countries lack reliable hazard information. One example has been the 2011 Thailand floods where millions of people were affected and the total economic losses were 30 billion USD. In order to assess the flood risk across different regions and countries, the flood team at Swiss Re based on a Geomorphologic Regression approach, developed in house and patented, produced global maps of flood zones. Input data for the study was obtained from NASA's Shuttle Radar Topographic Mission (SRTM) elevation data, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (GDEM) and HydroSHEDS. The underlying assumptions of the approach are that naturally flowing rivers shape their channel and flood plain according to basin inherent forces and characteristics and that the flood water extent strongly depends on the shape of the flood plain. On the basis of the catchment characteristics, the model finally calculates the probability of a location to be flooded or not for a defined return period, which in the current study was set to 100 years. The data is produced at a 90-m resolution for latitudes 60S to 60N. This global product is now used in the insurance industry to inspect, inform and/or insure the flood risk across the world.

Climatic control of Mississippi River flood hazard amplified by river engineering

Science.gov (United States)

Munoz, Samuel E.; Giosan, Liviu; Therrell, Matthew D.; Remo, Jonathan W. F.; Shen, Zhixiong; Sullivan, Richard M.; Wiman, Charlotte; O’Donnell, Michelle; Donnelly, Jeffrey P.

2018-04-01

Over the past century, many of the world’s major rivers have been modified for the purposes of flood mitigation, power generation and commercial navigation. Engineering modifications to the Mississippi River system have altered the river’s sediment levels and channel morphology, but the influence of these modifications on flood hazard is debated. Detecting and attributing changes in river discharge is challenging because instrumental streamflow records are often too short to evaluate the range of natural hydrological variability before the establishment of flood mitigation infrastructure. Here we show that multi-decadal trends of flood hazard on the lower Mississippi River are strongly modulated by dynamical modes of climate variability, particularly the El Niño–Southern Oscillation and the Atlantic Multidecadal Oscillation, but that the artificial channelization (confinement to a straightened channel) has greatly amplified flood magnitudes over the past century. Our results, based on a multi-proxy reconstruction of flood frequency and magnitude spanning the past 500 years, reveal that the magnitude of the 100-year flood (a flood with a 1 per cent chance of being exceeded in any year) has increased by 20 per cent over those five centuries, with about 75 per cent of this increase attributed to river engineering. We conclude that the interaction of human alterations to the Mississippi River system with dynamical modes of climate variability has elevated the current flood hazard to levels that are unprecedented within the past five centuries.

Differences in flood hazard projections in Europe – their causes and consequences for decision making

Science.gov (United States)

Kundzewicz, Z. W.; Krysanova, V.; Dankers, R.; Hirabayashi, Y.; Kanae, S.; Hattermann, F. F.; Huang, S.; Milly, Paul C.D.; Stoffel, M.; Driessen, P.P.J.; Matczak, P.; Quevauviller, P.; Schellnhuber, H.-J.

2017-01-01

This paper interprets differences in flood hazard projections over Europe and identifies likely sources of discrepancy. Further, it discusses potential implications of these differences for flood risk reduction and adaptation to climate change. The discrepancy in flood hazard projections raises caution, especially among decision makers in charge of water resources management, flood risk reduction, and climate change adaptation at regional to local scales. Because it is naïve to expect availability of trustworthy quantitative projections of future flood hazard, in order to reduce flood risk one should focus attention on mapping of current and future risks and vulnerability hotspots and improve the situation there. Although an intercomparison of flood hazard projections is done in this paper and differences are identified and interpreted, it does not seems possible to recommend which large-scale studies may be considered most credible in particular areas of Europe.

Toward economic flood loss characterization via hazard simulation

Science.gov (United States)

Czajkowski, Jeffrey; Cunha, Luciana K.; Michel-Kerjan, Erwann; Smith, James A.

2016-08-01

Among all natural disasters, floods have historically been the primary cause of human and economic losses around the world. Improving flood risk management requires a multi-scale characterization of the hazard and associated losses—the flood loss footprint. But this is typically not available in a precise and timely manner, yet. To overcome this challenge, we propose a novel and multidisciplinary approach which relies on a computationally efficient hydrological model that simulates streamflow for scales ranging from small creeks to large rivers. We adopt a normalized index, the flood peak ratio (FPR), to characterize flood magnitude across multiple spatial scales. The simulated FPR is then shown to be a key statistical driver for associated economic flood losses represented by the number of insurance claims. Importantly, because it is based on a simulation procedure that utilizes generally readily available physically-based data, our flood simulation approach has the potential to be broadly utilized, even for ungauged and poorly gauged basins, thus providing the necessary information for public and private sector actors to effectively reduce flood losses and save lives.

12 CFR 22.6 - Required use of standard flood hazard determination form.

Science.gov (United States)

2010-01-01

... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Required use of standard flood hazard determination form. 22.6 Section 22.6 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY... the Act. The standard flood hazard determination form may be used in a printed, computerized, or...

Differences in flood hazard projections in Europe – their causes and consequences for decision making

NARCIS (Netherlands)

Kundzewicz, Zbigniew W.; Krysanova, V.; Dankers, R.; Hirabayashi, Y.; Kanae, S.; Hattermann, F. F.; Huang, S.; Milly, P. C. D.; Stoffel, M.H.; Driessen, P. P. J.; Matczak, Piotr; Quevauviller, P.; Schellnhuber, H. J.

2017-01-01

This paper interprets differences in flood hazard projections over Europe and identifies likely sources of discrepancy. Further, it discusses potential implications of these differences for flood risk reduction and adaptation to climate change. The discrepancy in flood hazard projections raises

44 CFR 65.11 - Evaluation of sand dunes in mapping coastal flood hazard areas.

Science.gov (United States)

2010-10-01

... mapping coastal flood hazard areas. 65.11 Section 65.11 Emergency Management and Assistance FEDERAL... Insurance Program IDENTIFICATION AND MAPPING OF SPECIAL HAZARD AREAS § 65.11 Evaluation of sand dunes in mapping coastal flood hazard areas. (a) General conditions. For purposes of the NFIP, FEMA will consider...

Identification and delineation of areas flood hazard using high accuracy of DEM data

Science.gov (United States)

Riadi, B.; Barus, B.; Widiatmaka; Yanuar, M. J. P.; Pramudya, B.

2018-05-01

Flood incidents that often occur in Karawang regency need to be mitigated. These expectations exist on technologies that can predict, anticipate and reduce disaster risks. Flood modeling techniques using Digital Elevation Model (DEM) data can be applied in mitigation activities. High accuracy DEM data used in modeling, will result in better flooding flood models. The result of high accuracy DEM data processing will yield information about surface morphology which can be used to identify indication of flood hazard area. The purpose of this study was to identify and describe flood hazard areas by identifying wetland areas using DEM data and Landsat-8 images. TerraSAR-X high-resolution data is used to detect wetlands from landscapes, while land cover is identified by Landsat image data. The Topography Wetness Index (TWI) method is used to detect and identify wetland areas with basic DEM data, while for land cover analysis using Tasseled Cap Transformation (TCT) method. The result of TWI modeling yields information about potential land of flood. Overlay TWI map with land cover map that produces information that in Karawang regency the most vulnerable areas occur flooding in rice fields. The spatial accuracy of the flood hazard area in this study was 87%.

Continuous hydrologic simulation and flood-frequency, hydraulic, and flood-hazard analysis of the Blackberry Creek watershed, Kane County, Illinois

Science.gov (United States)

Soong, David T.; Straub, Timothy D.; Murphy, Elizabeth A.

2006-01-01

Results of hydrologic model, flood-frequency, hydraulic model, and flood-hazard analysis of the Blackberry Creek watershed in Kane County, Illinois, indicate that the 100-year and 500-year flood plains range from approximately 25 acres in the tributary F watershed (a headwater subbasin at the northeastern corner of the watershed) to almost 1,800 acres in Blackberry Creek main stem. Based on 1996 land-cover data, most of the land in the 100-year and 500-year flood plains was cropland, forested and wooded land, and grassland. A relatively small percentage of urban land was in the flood plains. The Blackberry Creek watershed has undergone rapid urbanization in recent decades. The population and urbanized lands in the watershed are projected to double from the 1990 condition by 2020. Recently, flood-induced damage has occurred more frequently in urbanized areas of the watershed. There are concerns about the effect of urbanization on flood peaks and volumes, future flood-mitigation plans, and potential effects on the water quality and stream habitats. This report describes the procedures used in developing the hydrologic models, estimating the flood-peak discharge magnitudes and recurrence intervals for flood-hazard analysis, developing the hydraulic model, and the results of the analysis in graphical and tabular form. The hydrologic model, Hydrological Simulation Program-FORTRAN (HSPF), was used to perform the simulation of continuous water movements through various patterns of land uses in the watershed. Flood-frequency analysis was applied to an annual maximum series to determine flood quantiles in subbasins for flood-hazard analysis. The Hydrologic Engineering Center-River Analysis System (HEC-RAS) hydraulic model was used to determine the 100-year and 500-year flood elevations, and to determine the 100-year floodway. The hydraulic model was calibrated and verified using high water marks and observed inundation maps for the July 17-18, 1996, flood event. Digital

The Use of Geospatial Technologies in Flood Hazard Mapping and Assessment: Case Study from River Evros

Science.gov (United States)

Mentzafou, Angeliki; Markogianni, Vasiliki; Dimitriou, Elias

2017-02-01

Many scientists link climate change to the increase of the extreme weather phenomena frequency, which combined with land use changes often lead to disasters with severe social and economic effects. Especially floods as a consequence of heavy rainfall can put vulnerable human and natural systems such as transboundary wetlands at risk. In order to meet the European Directive 2007/60/EC requirements for the development of flood risk management plans, the flood hazard map of Evros transboundary watershed was produced after a grid-based GIS modelling method that aggregates the main factors related to the development of floods: topography, land use, geology, slope, flow accumulation and rainfall intensity. The verification of this tool was achieved through the comparison between the produced hazard map and the inundation maps derived from the supervised classification of Landsat 5 and 7 satellite imageries of four flood events that took place at Evros delta proximity, a wetland of international importance. The comparison of the modelled output (high and very high flood hazard areas) with the extent of the inundated areas as mapped from the satellite data indicated the satisfactory performance of the model. Furthermore, the vulnerability of each land use against the flood events was examined. Geographically Weighted Regression has also been applied between the final flood hazard map and the major factors in order to ascertain their contribution to flood events. The results accredited the existence of a strong relationship between land uses and flood hazard indicating the flood susceptibility of the lowlands and agricultural land. A dynamic transboundary flood hazard management plan should be developed in order to meet the Flood Directive requirements for adequate and coordinated mitigation practices to reduce flood risk.

Scoping of flood hazard mapping needs for Cumberland County, Maine

Science.gov (United States)

Dudley, Robert W.; Schalk, Charles W.

2006-01-01

This report was prepared by the U.S. Geological Survey (USGS) Maine Water Science Center as the deliverable for scoping of flood hazard mapping needs for Cumberland County, Maine, under Federal Emergency Management Agency (FEMA) Inter-Agency Agreement Number HSFE01-05-X-0018. This section of the report explains the objective of the task and the purpose of the report. The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine State Planning Office Floodplain Management Program, began scoping work in 2005 for Cumberland County. Scoping activities included assembling existing data and map needs information for communities in Cumberland County, documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) Database or its successor with information gathered during the scoping process. The average age of the FEMA floodplain maps in Cumberland County, Maine is 21 years. Most of these studies were in the early to mid 1980s. However, in the ensuing 20-25 years, development has occurred in many of the

Scoping of flood hazard mapping needs for Kennebec County, Maine

Science.gov (United States)

Dudley, Robert W.; Schalk, Charles W.

2006-01-01

This report was prepared by the U.S. Geological Survey (USGS) Maine Water Science Center as the deliverable for scoping of flood hazard mapping needs for Kennebec County, Maine, under Federal Emergency Management Agency (FEMA) Inter-Agency Agreement Number HSFE01-05-X-0018. This section of the report explains the objective of the task and the purpose of the report. The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine State Planning Office Floodplain Management Program, began scoping work in 2005 for Kennebec County. Scoping activities included assembling existing data and map needs information for communities in Kennebec County (efforts were made to not duplicate those of pre-scoping completed in March 2005), documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) Database or its successor with information gathered during the scoping process. The average age of the FEMA floodplain maps in Kennebec County, Maine is 16 years. Most of these studies were in the late 1970's to the mid 1980s

Scoping of flood hazard mapping needs for Somerset County, Maine

Science.gov (United States)

Dudley, Robert W.; Schalk, Charles W.

2006-01-01

This report was prepared by the U.S. Geological Survey (USGS) Maine Water Science Center as the deliverable for scoping of flood hazard mapping needs for Somerset County, Maine, under Federal Emergency Management Agency (FEMA) Inter-Agency Agreement Number HSFE01-05-X-0018. This section of the report explains the objective of the task and the purpose of the report. The Federal Emergency Management Agency (FEMA) developed a plan in 1997 to modernize the FEMA flood mapping program. FEMA flood maps delineate flood hazard areas in support of the National Flood Insurance Program (NFIP). FEMA's plan outlined the steps necessary to update FEMA's flood maps for the nation to a seamless digital format and streamline FEMA's operations in raising public awareness of the importance of the maps and responding to requests to revise them. The modernization of flood maps involves conversion of existing information to digital format and integration of improved flood hazard data as needed. To determine flood mapping modernization needs, FEMA has established specific scoping activities to be done on a county-by-county basis for identifying and prioritizing requisite flood-mapping activities for map modernization. The U.S. Geological Survey (USGS), in cooperation with FEMA and the Maine State Planning Office Floodplain Management Program, began scoping work in 2005 for Somerset County. Scoping activities included assembling existing data and map needs information for communities in Somerset County (efforts were made to not duplicate those of pre-scoping completed in March 2005), documentation of data, contacts, community meetings, and prioritized mapping needs in a final scoping report (this document), and updating the Mapping Needs Update Support System (MNUSS) Database or its successor with information gathered during the scoping process. The average age of the FEMA floodplain maps in Somerset County, Maine is 18.1 years. Most of these studies were in the late 1970's to the mid 1980

Integrating Entropy-Based Naïve Bayes and GIS for Spatial Evaluation of Flood Hazard.

Science.gov (United States)

Liu, Rui; Chen, Yun; Wu, Jianping; Gao, Lei; Barrett, Damian; Xu, Tingbao; Li, Xiaojuan; Li, Linyi; Huang, Chang; Yu, Jia

2017-04-01

Regional flood risk caused by intensive rainfall under extreme climate conditions has increasingly attracted global attention. Mapping and evaluation of flood hazard are vital parts in flood risk assessment. This study develops an integrated framework for estimating spatial likelihood of flood hazard by coupling weighted naïve Bayes (WNB), geographic information system, and remote sensing. The north part of Fitzroy River Basin in Queensland, Australia, was selected as a case study site. The environmental indices, including extreme rainfall, evapotranspiration, net-water index, soil water retention, elevation, slope, drainage proximity, and density, were generated from spatial data representing climate, soil, vegetation, hydrology, and topography. These indices were weighted using the statistics-based entropy method. The weighted indices were input into the WNB-based model to delineate a regional flood risk map that indicates the likelihood of flood occurrence. The resultant map was validated by the maximum inundation extent extracted from moderate resolution imaging spectroradiometer (MODIS) imagery. The evaluation results, including mapping and evaluation of the distribution of flood hazard, are helpful in guiding flood inundation disaster responses for the region. The novel approach presented consists of weighted grid data, image-based sampling and validation, cell-by-cell probability inferring and spatial mapping. It is superior to an existing spatial naive Bayes (NB) method for regional flood hazard assessment. It can also be extended to other likelihood-related environmental hazard studies. © 2016 Society for Risk Analysis.

Development of a Probabilistic Flood Hazard Assessment (PFHA) for the nuclear safety

Science.gov (United States)

Ben Daoued, Amine; Guimier, Laurent; Hamdi, Yasser; Duluc, Claire-Marie; Rebour, Vincent

2016-04-01

The purpose of this study is to lay the basis for a probabilistic evaluation of flood hazard (PFHA). Probabilistic assessment of external floods has become a current topic of interest to the nuclear scientific community. Probabilistic approaches complement deterministic approaches by exploring a set of scenarios and associating a probability to each of them. These approaches aim to identify all possible failure scenarios, combining their probability, in order to cover all possible sources of risk. They are based on the distributions of initiators and/or the variables caracterizing these initiators. The PFHA can characterize the water level for example at defined point of interest in the nuclear site. This probabilistic flood hazard characterization takes into account all the phenomena that can contribute to the flooding of the site. The main steps of the PFHA are: i) identification of flooding phenomena (rains, sea water level, etc.) and screening of relevant phenomena to the nuclear site, ii) identification and probabilization of parameters associated to selected flooding phenomena, iii) spreading of the probabilized parameters from the source to the point of interest in the site, v) obtaining hazard curves and aggregation of flooding phenomena contributions at the point of interest taking into account the uncertainties. Within this framework, the methodology of the PFHA has been developed for several flooding phenomena (rain and/or sea water level, etc.) and then implemented and tested with a simplified case study. In the same logic, our study is still in progress to take into account other flooding phenomena and to carry out more case studies.

FEMA Hazard Mitigation Assistance Flood Mitigation Assistance (FMA) Data

Data.gov (United States)

Department of Homeland Security — This dataset contains closed and obligated projects funded under the following Hazard Mitigation Assistance (HMA) grant programs: Flood Mitigation Assistance (FMA)....

FEMA Hazard Mitigation Assistance Repetitive Flood Claims (RFC) Data

Data.gov (United States)

Department of Homeland Security — This dataset contains closed and obligated projects funded under the following Hazard Mitigation Assistance (HMA) grant programs: Repetitive Flood Claims (RFC). The...

The use of a flood index to characterise flooding in the north-eastern region of Bangladesh

Directory of Open Access Journals (Sweden)

Bhattacharya B.

2016-01-01

Full Text Available Flooding in the Haor region in the north-east of Bangladesh is presented in this paper. A haor is a saucershaped depression, which is used during the dry period (Dec to mid-May for agriculture and as a fishery during the wet period (Jun-Nov. Pre-monsoon flooding till mid-May causes agricultural loss. The area is bordering India, and is fed by some flashy Indian catchments. The area is drained mainly by the Surma-Kushiyara river system. The terrain generally is flat and the flashy characteristics die out within a short distance from the border. Limited studies on the region, particularly with the help of numerical models, have been carried out in the past. Therefore, an objective of the current research was to set up numerical models capable of reasonably emulating the physical system. Such models could, for example, associate different gauges to the spatio-temporal variation of hydrodynamic variables and help in carrying out a systemic study on the flood propagation. A 1D2D model, with one-dimensional model for the rivers (based on MIKE 11 from DHI and a two-dimensional model for the haors (based on MIKE 21 from DHI were developed. In order to characterize flooding in the large area a flood index is proposed, which is computed based on the hydrograph characteristics such as the rising curve gradient, flood magnitude ratio and time to peak. The index was used in characterising flooding in the Haor region. In general, two groups of rivers were identified. The study enabled identifying the hot-spots in the study area with risks from flooding.

A national scale flood hazard mapping methodology: The case of Greece - Protection and adaptation policy approaches.

Science.gov (United States)

Kourgialas, Nektarios N; Karatzas, George P

2017-12-01

The present work introduces a national scale flood hazard assessment methodology, using multi-criteria analysis and artificial neural networks (ANNs) techniques in a GIS environment. The proposed methodology was applied in Greece, where flash floods are a relatively frequent phenomenon and it has become more intense over the last decades, causing significant damages in rural and urban sectors. In order the most prone flooding areas to be identified, seven factor-maps (that are directly related to flood generation) were combined in a GIS environment. These factor-maps are: a) the Flow accumulation (F), b) the Land use (L), c) the Altitude (A), b) the Slope (S), e) the soil Erodibility (E), f) the Rainfall intensity (R), and g) the available water Capacity (C). The name to the proposed method is "FLASERC". The flood hazard for each one of these factors is classified into five categories: Very low, low, moderate, high, and very high. The above factors are combined and processed using the appropriate ANN algorithm tool. For the ANN training process spatial distribution of historical flooded points in Greece within the five different flood hazard categories of the aforementioned seven factor-maps were combined. In this way, the overall flood hazard map for Greece was determined. The final results are verified using additional historical flood events that have occurred in Greece over the last 100years. In addition, an overview of flood protection measures and adaptation policy approaches were proposed for agricultural and urban areas located at very high flood hazard areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Coastal Flooding Hazards due to storm surges and subsidence

DEFF Research Database (Denmark)

Sørensen, Carlo; Knudsen, Per; Andersen, Ole B.

Flooding hazard and risk mapping are major topics in low-lying coastal areas before even considering the adverse effects of sea level rise (SLR) due to climate change. While permanent inundation may be a prevalent issue, more often floods related to extreme events (storm surges) have the largest...... damage potential.Challenges are amplified in some areas due to subsidence from natural and/or anthropogenic causes. Subsidence of even a few mm/y may over time greatly impair the safety against flooding of coastal communities and must be accounted for in order to accomplish the economically most viable...

Climate change-induced impacts on urban flood risk influenced by concurrent hazards

DEFF Research Database (Denmark)

Pedersen, A. N.; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten

2012-01-01

hazards, rainfall and sea surge, are both important. The core in the methodology is the application of copula functions as an extension of one-dimensional risk analysis and projections of future climatic changes. The results for Greater Copenhagen indicate that the dependence between the hazards is weak......In coastal regions, several hazards may lead to floods, and if they occur concurrently, the damage will be higher than for the hazards individually. The paper outlines an approach for carrying out a risk analysis with several hazards and applies it on a case study in Greater Copenhagen where two...... and that climate change most likely will not increase the correlation. The overall change in flood return periods over a forecast horizon of 110 years are estimated to decrease by one to three orders of magnitude....

Assessment of vulnerability to storm induced flood hazard along diverse coastline settings

Directory of Open Access Journals (Sweden)

Valchev Nikolay

2016-01-01

Full Text Available European coasts suffer notably from hazards caused by low-probability and high-impact hydrometeorological events. The aim of the study is to assess in probabilistic terms the magnitude of storm‐induced flooding hazard along Varna regional coast (Bulgaria, western Black Sea and to identify susceptible coastal sectors (hotspots. The study is performed employing the Coastal Risk Assessment Framework (CRAF developed within EU FP7 RISC-KIT project. It constitutes a screening process that allows estimation of relevant hazard intensities, extents and potential receptors’ exposure vulnerability within predefined sectors. Total water level was the chief property considered for calculation of coastal flooding hazard. It was estimated using Holman model (for sandy beaches and EurOtop formulation (for artificial or rocky slopes. Resulting values were subjected to Extreme Value Analysis to establish that the best fitting distribution corresponds to Generalized Extreme Value distribution. Furthermore, hazard extents were modelled by means of bathtubbing or overwash estimation in order to form the flooding hazard indicator. Land use, social vulnerability, transport systems, utilities and business settings were considered as exposure indicators. Finally, potential risk was assessed by coastal indices following an index-based methodology, which combines hazard and exposure indicators into a single index, thereby providing base for comparison of coastal sectors’ vulnerability. The study found that the concentration of hotspots is highest in Varna Bay.

Combined fluvial and pluvial urban flood hazard analysis: method development and application to Can Tho City, Mekong Delta, Vietnam

Science.gov (United States)

Apel, H.; Trepat, O. M.; Hung, N. N.; Chinh, D. T.; Merz, B.; Dung, N. V.

2015-08-01

Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas, and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either fluvial or pluvial flood hazard, studies of combined fluvial and pluvial flood hazard are hardly available. Thus this study aims at the analysis of fluvial and pluvial flood hazard individually, but also at developing a method for the analysis of combined pluvial and fluvial flood hazard. This combined fluvial-pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as example. In this tropical environment the annual monsoon triggered floods of the Mekong River can coincide with heavy local convective precipitation events causing both fluvial and pluvial flooding at the same time. Fluvial flood hazard was estimated with a copula based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. Pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data, and a stochastic rain storm generator. Inundation was simulated by a 2-dimensional hydrodynamic model implemented on a Graphical Processor Unit (GPU) for time-efficient flood propagation modelling. All hazards - fluvial, pluvial and combined - were accompanied by an uncertainty estimation considering the natural variability of the flood events. This resulted in probabilistic flood hazard maps showing the maximum inundation depths for a selected set of probabilities of occurrence, with maps showing the expectation (median) and the uncertainty by

Evaluation of flood hazard maps in print and web mapping services as information tools in flood risk communication

Science.gov (United States)

Hagemeier-Klose, M.; Wagner, K.

2009-04-01

Flood risk communication with the general public and the population at risk is getting increasingly important for flood risk management, especially as a precautionary measure. This is also underlined by the EU Flood Directive. The flood related authorities therefore have to develop adjusted information tools which meet the demands of different user groups. This article presents the formative evaluation of flood hazard maps and web mapping services according to the specific requirements and needs of the general public using the dynamic-transactional approach as a theoretical framework. The evaluation was done by a mixture of different methods; an analysis of existing tools, a creative workshop with experts and laymen and an online survey. The currently existing flood hazard maps or web mapping services or web GIS still lack a good balance between simplicity and complexity with adequate readability and usability for the public. Well designed and associative maps (e.g. using blue colours for water depths) which can be compared with past local flood events and which can create empathy in viewers, can help to raise awareness, to heighten the activity and knowledge level or can lead to further information seeking. Concerning web mapping services, a linkage between general flood information like flood extents of different scenarios and corresponding water depths and real time information like gauge levels is an important demand by users. Gauge levels of these scenarios are easier to understand than the scientifically correct return periods or annualities. The recently developed Bavarian web mapping service tries to integrate these requirements.

Evaluation of flood hazard maps in print and web mapping services as information tools in flood risk communication

Directory of Open Access Journals (Sweden)

M. Hagemeier-Klose

2009-04-01

Full Text Available Flood risk communication with the general public and the population at risk is getting increasingly important for flood risk management, especially as a precautionary measure. This is also underlined by the EU Flood Directive. The flood related authorities therefore have to develop adjusted information tools which meet the demands of different user groups. This article presents the formative evaluation of flood hazard maps and web mapping services according to the specific requirements and needs of the general public using the dynamic-transactional approach as a theoretical framework. The evaluation was done by a mixture of different methods; an analysis of existing tools, a creative workshop with experts and laymen and an online survey.

The currently existing flood hazard maps or web mapping services or web GIS still lack a good balance between simplicity and complexity with adequate readability and usability for the public. Well designed and associative maps (e.g. using blue colours for water depths which can be compared with past local flood events and which can create empathy in viewers, can help to raise awareness, to heighten the activity and knowledge level or can lead to further information seeking. Concerning web mapping services, a linkage between general flood information like flood extents of different scenarios and corresponding water depths and real time information like gauge levels is an important demand by users. Gauge levels of these scenarios are easier to understand than the scientifically correct return periods or annualities. The recently developed Bavarian web mapping service tries to integrate these requirements.

Morphometric and landuse analysis: implications on flood hazards ...

African Journals Online (AJOL)

This study assessed the morphometric, landuse and lithological attributes of five basins (Iwaraja, Ilesa, Olupona, Osogbo I and Osogbo II) with particular reference to flood hazards in Ilesa and Osogbo metropolis, Osun State Nigeria. Ilesa town is situated within Iwaraja and Ilesa basins while Osogbo metropolis spread ...

77 FR 76499 - Changes in Flood Hazard Determinations

Science.gov (United States)

2012-12-28

... Federal, State, or regional entities. These new or modified flood hazard determinations are used to meet... Orlando, FL 32801. South John Young Parkway, Orlando, FL 32839. Orange (FEMA Docket No.: B- Unincorporated... Orlando, FL 32801. South John Young Parkway, Orlando, FL 32839. Pinellas (FEMA Docket No.: B- City of...

Impacts of dyke development in flood prone areas in the Vietnamese Mekong Delta to downstream flood hazard

Science.gov (United States)

Khanh Triet Nguyen, Van; Dung Nguyen, Viet; Fujii, Hideto; Kummu, Matti; Merz, Bruno; Apel, Heiko

2016-04-01

The Vietnamese Mekong Delta (VMD) plays an important role in food security and socio-economic development of the country. Being a low-lying coastal region, the VMD is particularly susceptible to both riverine and tidal floods, which provide, on (the) one hand, the basis for the rich agricultural production and the livelihood of the people, but on the other hand pose a considerable hazard depending on the severity of the floods. But despite of potentially hazardous flood, the area remain active as a rice granary due to its nutrient-rich soils and sediment input, and dense waterways, canals and the long standing experience of the population living with floods. In response to both farmers' requests and governmental plans, the construction of flood protection infrastructure in the delta progressed rapidly in the last twenty years, notably at areas prone to deep flooding, i.e. the Plain of Reeds (PoR) and Long Xuyen Quadrangle (LXQ). Triple rice cropping becomes possible in farmlands enclosed by "full-dykes", i.e. dykes strong and high enough to prevent flooding of the flood plains for most of the floods. In these protected flood plains rice can be grown even during the peak flood period (September to November). However, little is known about the possibly (and already alleged) negative impacts of this fully flood protection measure to downstream areas. This study aims at quantifying how the flood regime in the lower part of the VMD (e.g. Can Tho, My Thuan, …) has been changed in the last 2 recent "big flood" events of 2000 and 2011 due to the construction of the full-dyke system in the upper part. First, an evaluation of 35 years of daily water level data was performed in order to detect trends at key gauging stations: Kratie: upper boundary of the Delta, Tan Chau and Chau Doc: areas with full-dyke construction, Can Tho and My Thuan: downstream. Results from the Mann-Kendall (MK) test show a decreasing trend of the annual maximum water level at 3 stations Kratie, Tan

Community's Emergency Preparedness for Flood Hazards in Dire-dawa Town, Ethiopia: A Qualitative Study.

Science.gov (United States)

Ejeta, Luche Tadesse

2018-02-21

Emergency preparedness at all levels (individuals and communities) is the corner stone of effective response to the increasing trends of global disasters due to man-made and natural hazards. It is determined by different factors, including (among others) past direct and indirect exposures to hazards. This study was carried out in Dire Dawa town, Ethiopia, which in the past experienced frequent flooding events, yet dearth of information exists about preparedness in the area.  The aim of the study was to assess the levels of emergency preparedness for flood hazards at households and communities levels. The study was conducted in a qualitative approach and was conducted in Dire Dawa town, which has been divided into nine administrative-units called Kebeles. Two focus group discussions were held in two of these units (Kebele-05 and 06), each focus group comprising twelve people (all above 18 years of age), and in total 24 people (13 females and 11 males) took part in the study. Open ended questions were used that could guide the discussions, and the discussions were audio-taped and transcribed. The results were translated from local language to English and qualitatively presented. The findings of focus group discussions showed that the local government in collaboration with the federal government built the flood protection dams in areas where flood hazards have been thought to be repeatedly wreaking havoc, specifically after the flood disaster of the year 2006. In addition, in Kebele-05, where one Non-Governmental Organization (NGO) was operating on flood hazards prevention and mitigation program, some non-structural emergency preparedness measures were undertaken by the communities. These non-structural measures (the major ones) entailed: establishment of committees recruited from residents and training them to raise awareness among communities on emergency preparedness; some residents made changes to their own houses (retrofitted) and put sandbags around their

Landslide and flood hazard assessment in urban areas of Levoča region (Eastern Slovakia)

Science.gov (United States)

Magulova, Barbora; Caporali, Enrica; Bednarik, Martin

2010-05-01

The case study presents the use of statistical methods and analysis tools, for hazard assessment of "urbanization units", implemented in a Geographic Information Systems (GIS) environment. As a case study, the Levoča region (Slovakia) is selected. The region, with a total area of about 351 km2, is widely affected by landslides and floods. The problem, for small urbanization areas, is nowadays particularly significant from the socio-economic point of view. It is considered, presently, also an increasing problem, mainly because of climate change and more frequent extreme rainfall events. The geo-hazards are evaluated using a multivariate analysis. The landslide hazard assessment is based on the comparison and subsequent statistical elaboration of territorial dependence among different input factors influencing the instability of the slopes. Particularly, five factors influencing slope stability are evaluated, i.e. lithology, slope aspect, slope angle, hypsographic level and present land use. As a result a new landslide susceptibility map is compiled and different zones of stable, dormant and non-stable areas are defined. For flood hazard map a detailed digital elevation model is created. A compose index of flood hazard is derived from topography, land cover and pedology related data. To estimate flood discharge, time series of stream flow and precipitation measurements are used. The assessment results are prognostic maps of landslide hazard and flood hazard, which presents the optimal base for urbanization planning.

Combined fluvial and pluvial urban flood hazard analysis: concept development and application to Can Tho city, Mekong Delta, Vietnam

Science.gov (United States)

Apel, Heiko; Martínez Trepat, Oriol; Nghia Hung, Nguyen; Thi Chinh, Do; Merz, Bruno; Viet Dung, Nguyen

2016-04-01

Many urban areas experience both fluvial and pluvial floods, because locations next to rivers are preferred settlement areas and the predominantly sealed urban surface prevents infiltration and facilitates surface inundation. The latter problem is enhanced in cities with insufficient or non-existent sewer systems. While there are a number of approaches to analyse either a fluvial or pluvial flood hazard, studies of a combined fluvial and pluvial flood hazard are hardly available. Thus this study aims to analyse a fluvial and a pluvial flood hazard individually, but also to develop a method for the analysis of a combined pluvial and fluvial flood hazard. This combined fluvial-pluvial flood hazard analysis is performed taking Can Tho city, the largest city in the Vietnamese part of the Mekong Delta, as an example. In this tropical environment the annual monsoon triggered floods of the Mekong River, which can coincide with heavy local convective precipitation events, causing both fluvial and pluvial flooding at the same time. The fluvial flood hazard was estimated with a copula-based bivariate extreme value statistic for the gauge Kratie at the upper boundary of the Mekong Delta and a large-scale hydrodynamic model of the Mekong Delta. This provided the boundaries for 2-dimensional hydrodynamic inundation simulation for Can Tho city. The pluvial hazard was estimated by a peak-over-threshold frequency estimation based on local rain gauge data and a stochastic rainstorm generator. Inundation for all flood scenarios was simulated by a 2-dimensional hydrodynamic model implemented on a Graphics Processing Unit (GPU) for time-efficient flood propagation modelling. The combined fluvial-pluvial flood scenarios were derived by adding rainstorms to the fluvial flood events during the highest fluvial water levels. The probabilities of occurrence of the combined events were determined assuming independence of the two flood types and taking the seasonality and probability of

Hazard Experience, Geophysical Vulnerability, and Flood Risk Perceptions in a Postdisaster City, the Case of New Orleans.

Science.gov (United States)

Gotham, Kevin Fox; Campanella, Richard; Lauve-Moon, Katie; Powers, Bradford

2018-02-01

This article investigates the determinants of flood risk perceptions in New Orleans, Louisiana (United States), a deltaic coastal city highly vulnerable to seasonal nuisance flooding and hurricane-induced deluges and storm surges. Few studies have investigated the influence of hazard experience, geophysical vulnerability (hazard proximity), and risk perceptions in cities undergoing postdisaster recovery and rebuilding. We use ordinal logistic regression techniques to analyze experiential, geophysical, and sociodemographic variables derived from a survey of 384 residents in seven neighborhoods. We find that residents living in neighborhoods that flooded during Hurricane Katrina exhibit higher levels of perceived risk than those residents living in neighborhoods that did not flood. In addition, findings suggest that flood risk perception is positively associated with female gender, lower income, and direct flood experiences. In conclusion, we discuss the implications of these findings for theoretical and empirical research on environmental risk, flood risk communication strategies, and flood hazards planning. © 2017 Society for Risk Analysis.

Validation of individual and aggregate global flood hazard models for two major floods in Africa.

Science.gov (United States)

Trigg, M.; Bernhofen, M.; Whyman, C.

2017-12-01

A recent intercomparison of global flood hazard models undertaken by the Global Flood Partnership shows that there is an urgent requirement to undertake more validation of the models against flood observations. As part of the intercomparison, the aggregated model dataset resulting from the project was provided as open access data. We compare the individual and aggregated flood extent output from the six global models and test these against two major floods in the African Continent within the last decade, namely severe flooding on the Niger River in Nigeria in 2012, and on the Zambezi River in Mozambique in 2007. We test if aggregating different number and combination of models increases model fit to the observations compared with the individual model outputs. We present results that illustrate some of the challenges of comparing imperfect models with imperfect observations and also that of defining the probability of a real event in order to test standard model output probabilities. Finally, we propose a collective set of open access validation flood events, with associated observational data and descriptions that provide a standard set of tests across different climates and hydraulic conditions.

Has land subsidence changed the flood hazard potential? A case example from the Kujukuri Plain, Chiba Prefecture, Japan

Directory of Open Access Journals (Sweden)

H. L. Chen

2015-11-01

Full Text Available Coastal areas are subject to flood hazards because of their topographic features, social development and related human activities. The Kujukuri Plain, Chiba Prefecture, Japan, is located nearby the Tokyo metropolitan area and it faces to the Pacific Ocean. In the Kujukuri Plain, widespread occurrence of land subsidence has been caused by exploitation of groundwater, extraction of natural gas dissolved in brine, and natural consolidation of the Holocene and landfill deposits. The locations of land subsidence include areas near the coast, and it may increase the flood hazard potential. Hence, it is very important to evaluate flood hazard potential by taking into account the temporal change of land elevation caused by land subsidence, and to prepare hazard maps for protecting the surface environment and for developing an appropriate land-use plan. In this study, flood hazard assessments at three different times, i.e., 1970, 2004, and 2013 are implemented by using a flood hazard model based on Multicriteria Decision Analysis with Geographical Information System techniques. The model incorporates six factors: elevation, depression area, river system, ratio of impermeable area, detention ponds, and precipitation. Main data sources used are 10 m resolution topography data, airborne laser scanning data, leveling data, Landsat-TM data, two 1:30 000 scale river watershed maps, and precipitation data from observation stations around the study area and Radar data. The hazard assessment maps for each time are obtained by using an algorithm that combines factors with weighted linear combinations. The assignment of the weight/rank values and their analysis are realized by the application of the Analytic Hierarchy Process method. This study is a preliminary work to investigate flood hazards on the Kujukuri Plain. A flood model will be developed to simulate more detailed change of the flood hazard influenced by land subsidence.

A framework for the case-specific assessment of Green Infrastructure in mitigating urban flood hazards

Science.gov (United States)

Schubert, Jochen E.; Burns, Matthew J.; Fletcher, Tim D.; Sanders, Brett F.

2017-10-01

This research outlines a framework for the case-specific assessment of Green Infrastructure (GI) performance in mitigating flood hazard in small urban catchments. The urban hydrologic modeling tool (MUSIC) is coupled with a fine resolution 2D hydrodynamic model (BreZo) to test to what extent retrofitting an urban watershed with GI, rainwater tanks and infiltration trenches in particular, can propagate flood management benefits downstream and support intuitive flood hazard maps useful for communicating and planning with communities. The hydrologic and hydraulic models are calibrated based on current catchment conditions, then modified to represent alternative GI scenarios including a complete lack of GI versus a full implementation of GI. Flow in the hydrologic/hydraulic models is forced using a range of synthetic rainfall events with annual exceedance probabilities (AEPs) between 1-63% and durations from 10 min to 24 h. Flood hazard benefits mapped by the framework include maximum flood depths and extents, flow intensity (m2/s), flood duration, and critical storm duration leading to maximum flood conditions. Application of the system to the Little Stringybark Creek (LSC) catchment shows that across the range of AEPs tested and for storm durations equal or less than 3 h, presently implemented GI reduces downstream flooded area on average by 29%, while a full implementation of GI would reduce downstream flooded area on average by 91%. A full implementation of GI could also lower maximum flow intensities by 83% on average, reducing the drowning hazard posed by urban streams and improving the potential for access by emergency responders. For storm durations longer than 3 h, a full implementation of GI lacks the capacity to retain the resulting rainfall depths and only reduces flooded area by 8% and flow intensity by 5.5%.

Analysis and GIS Mapping of Flooding Hazards on 10 May 2016, Guangzhou, China

Directory of Open Access Journals (Sweden)

Hai-Min Lyu

2016-10-01

Full Text Available On 10 May 2016, Guangdong Province, China, suffered a heavy rainstorm. This rainstorm flooded the whole city of Guangzhou. More than 100,000 people were affected by the flooding, in which eight people lost their lives. Subway stations, cars, and buses were submerged. In order to analyse the influential factors of this flooding, topographical characteristics were mapped using Digital Elevation Model (DEM by the Geographical Information System (GIS and meteorological conditions were statistically summarised at both the whole city level and the district level. To analyse the relationship between flood risk and urbanization, GIS was also adopted to map the effect of the subway system using the Multiple Buffer operator over the flooding distribution area. Based on the analyses, one of the significant influential factors of flooding was identified as the urbanization degree, e.g., construction of a subway system, which forms along flood-prone areas. The total economic loss due to flooding in city centers with high urbanization has become very serious. Based on the analyses, the traditional standard of severity of flooding hazards (rainfall intensity grade was modified. Rainfall intensity for severity flooding was decreased from 50 mm to 30 mm in urbanized city centers. In order to protect cities from flooding, a “Sponge City” planning approach is recommended to increase the temporary water storage capacity during heavy rainstorms. In addition, for future city management, the combined use of GIS and Building Information Modelling (BIM is recommended to evaluate flooding hazards.

77 FR 74856 - Changes in Flood Hazard Determinations

Science.gov (United States)

2012-12-18

... entities. These new or modified flood hazard determinations are used to meet the floodplain management.... Marathon, FL 33050. Orange (FEMA Docket No.: B- City of Orlando (11- The Honorable Buddy Dyer, Permitting Services, 400 May 9, 2012 120186 1249). 04-8127P). Mayor, City of Orlando, South Orange Avenue, P.O. Box...

Effects of anthropogenic land-subsidence on river flood hazard: a case study in Ravenna, Italy

Science.gov (United States)

Carisi, Francesca; Domeneghetti, Alessio; Castellarin, Attilio

2015-04-01

Can differential land-subsidence significantly alter the river flooding dynamics, and thus flood risk in flood prone areas? Many studies show how the lowering of the coastal areas is closely related to an increase in the flood-hazard due to more important tidal flooding and see level rise. On the contrary, the literature on the relationship between differential land-subsidence and possible alterations to riverine flood-hazard of inland areas is still sparse, while several areas characterized by significant land-subsidence rates during the second half of the 20th century experienced an intensification in both inundation magnitude and frequency. This study investigates the possible impact of a significant differential ground lowering on flood hazard in proximity of Ravenna, which is one of the oldest Italian cities, former capital of the Western Roman Empire, located a few kilometers from the Adriatic coast and about 60 km south of the Po River delta. The rate of land-subsidence in the area, naturally in the order of a few mm/year, dramatically increased up to 110 mm/year after World War II, primarily due to groundwater pumping and a number of deep onshore and offshore gas production platforms. The subsidence caused in the last century a cumulative drop larger than 1.5 m in the historical center of the city. Starting from these evidences and taking advantage of a recent digital elevation model of 10m resolution, we reconstructed the ground elevation in 1897 for an area of about 65 km2 around the city of Ravenna. We referred to these two digital elevation models (i.e. current topography and topographic reconstruction) and a 2D finite-element numerical model for the simulation of the inundation dynamics associated with several levee failure scenarios along embankment system of the river Montone. For each scenario and digital elevation model, the flood hazard is quantified in terms of water depth, speed and dynamics of the flooding front. The comparison enabled us to

Exploring local risk managers' use of flood hazard maps for risk communication purposes in Baden-Württemberg

Directory of Open Access Journals (Sweden)

S. Kjellgren

2013-07-01

Full Text Available In response to the EU Floods Directive (2007/60/EC, flood hazard maps are currently produced all over Europe, reflecting a wider shift in focus from "flood protection" to "risk management", for which not only public authorities but also populations at risk are seen as responsible. By providing a visual image of the foreseen consequences of flooding, flood hazard maps can enhance people's knowledge about flood risk, making them more capable of an adequate response. Current literature, however, questions the maps' awareness raising capacity, arguing that their content and design are rarely adjusted to laypeople's needs. This paper wants to complement this perspective with a focus on risk communication by studying how these tools are disseminated and marketed to the public in the first place. Judging from communication theory, simply making hazard maps publicly available is unlikely to lead to attitudinal or behavioral effects, since this typically requires two-way communication and material or symbolic incentives. Consequently, it is relevant to investigate whether and how local risk managers, who are well positioned to interact with the local population, make use of flood hazard maps for risk communication purposes. A qualitative case study of this issue in the German state of Baden-Württemberg suggests that many municipalities lack a clear strategy for using this new information tool for hazard and risk communication. Four barriers in this regard are identified: perceived disinterest/sufficient awareness on behalf of the population at risk; unwillingness to cause worry or distress; lack of skills and resources; and insufficient support. These barriers are important to address – in research as well as in practice – since it is only if flood hazard maps are used to enhance local knowledge resources that they can be expected to contribute to social capacity building.

Exploring local risk managers' use of flood hazard maps for risk communication purposes in Baden-Württemberg

Science.gov (United States)

Kjellgren, S.

2013-07-01

In response to the EU Floods Directive (2007/60/EC), flood hazard maps are currently produced all over Europe, reflecting a wider shift in focus from "flood protection" to "risk management", for which not only public authorities but also populations at risk are seen as responsible. By providing a visual image of the foreseen consequences of flooding, flood hazard maps can enhance people's knowledge about flood risk, making them more capable of an adequate response. Current literature, however, questions the maps' awareness raising capacity, arguing that their content and design are rarely adjusted to laypeople's needs. This paper wants to complement this perspective with a focus on risk communication by studying how these tools are disseminated and marketed to the public in the first place. Judging from communication theory, simply making hazard maps publicly available is unlikely to lead to attitudinal or behavioral effects, since this typically requires two-way communication and material or symbolic incentives. Consequently, it is relevant to investigate whether and how local risk managers, who are well positioned to interact with the local population, make use of flood hazard maps for risk communication purposes. A qualitative case study of this issue in the German state of Baden-Württemberg suggests that many municipalities lack a clear strategy for using this new information tool for hazard and risk communication. Four barriers in this regard are identified: perceived disinterest/sufficient awareness on behalf of the population at risk; unwillingness to cause worry or distress; lack of skills and resources; and insufficient support. These barriers are important to address - in research as well as in practice - since it is only if flood hazard maps are used to enhance local knowledge resources that they can be expected to contribute to social capacity building.

Flash Flood Hazard Susceptibility Mapping Using Frequency Ratio and Statistical Index Methods in Coalmine Subsidence Areas

Directory of Open Access Journals (Sweden)

Chen Cao

2016-09-01

Full Text Available This study focused on producing flash flood hazard susceptibility maps (FFHSM using frequency ratio (FR and statistical index (SI models in the Xiqu Gully (XQG of Beijing, China. First, a total of 85 flash flood hazard locations (n = 85 were surveyed in the field and plotted using geographic information system (GIS software. Based on the flash flood hazard locations, a flood hazard inventory map was built. Seventy percent (n = 60 of the flooding hazard locations were randomly selected for building the models. The remaining 30% (n = 25 of the flooded hazard locations were used for validation. Considering that the XQG used to be a coal mining area, coalmine caves and subsidence caused by coal mining exist in this catchment, as well as many ground fissures. Thus, this study took the subsidence risk level into consideration for FFHSM. The ten conditioning parameters were elevation, slope, curvature, land use, geology, soil texture, subsidence risk area, stream power index (SPI, topographic wetness index (TWI, and short-term heavy rain. This study also tested different classification schemes for the values for each conditional parameter and checked their impacts on the results. The accuracy of the FFHSM was validated using area under the curve (AUC analysis. Classification accuracies were 86.61%, 83.35%, and 78.52% using frequency ratio (FR-natural breaks, statistical index (SI-natural breaks and FR-manual classification schemes, respectively. Associated prediction accuracies were 83.69%, 81.22%, and 74.23%, respectively. It was found that FR modeling using a natural breaks classification method was more appropriate for generating FFHSM for the Xiqu Gully.

Damage assessment of bridge infrastructure subjected to flood-related hazards

Science.gov (United States)

Michalis, Panagiotis; Cahill, Paul; Bekić, Damir; Kerin, Igor; Pakrashi, Vikram; Lapthorne, John; Morais, João Gonçalo Martins Paulo; McKeogh, Eamon

2017-04-01

Transportation assets represent a critical component of society's infrastructure systems. Flood-related hazards are considered one of the main climate change impacts on highway and railway infrastructure, threatening the security and functionality of transportation systems. Of such hazards, flood-induced scour is a primarily cause of bridge collapses worldwide and one of the most complex and challenging water flow and erosion phenomena, leading to structural instability and ultimately catastrophic failures. Evaluation of scour risk under severe flood events is a particularly challenging issue considering that depth of foundations is very difficult to evaluate in water environment. The continual inspection, assessment and maintenance of bridges and other hydraulic structures under extreme flood events requires a multidisciplinary approach, including knowledge and expertise of hydraulics, hydrology, structural engineering, geotechnics and infrastructure management. The large number of bridges under a single management unit also highlights the need for efficient management, information sharing and self-informing systems to provide reliable, cost-effective flood and scour risk management. The "Intelligent Bridge Assessment Maintenance and Management System" (BRIDGE SMS) is an EU/FP7 funded project which aims to couple state-of-the art scientific expertise in multidisciplinary engineering sectors with industrial knowledge in infrastructure management. This involves the application of integrated low-cost structural health monitoring systems to provide real-time information towards the development of an intelligent decision support tool and a web-based platform to assess and efficiently manage bridge assets. This study documents the technological experience and presents results obtained from the application of sensing systems focusing on the damage assessment of water-hazards at bridges over watercourses in Ireland. The applied instrumentation is interfaced with an open

Data assimilation of citizen collected information for real-time flood hazard mapping

Science.gov (United States)

Sayama, T.; Takara, K. T.

2017-12-01

Many studies in data assimilation in hydrology have focused on the integration of satellite remote sensing and in-situ monitoring data into hydrologic or land surface models. For flood predictions also, recent studies have demonstrated to assimilate remotely sensed inundation information with flood inundation models. In actual flood disaster situations, citizen collected information including local reports by residents and rescue teams and more recently tweets via social media also contain valuable information. The main interest of this study is how to effectively use such citizen collected information for real-time flood hazard mapping. Here we propose a new data assimilation technique based on pre-conducted ensemble inundation simulations and update inundation depth distributions sequentially when local data becomes available. The propose method is composed by the following two-steps. The first step is based on weighting average of preliminary ensemble simulations, whose weights are updated by Bayesian approach. The second step is based on an optimal interpolation, where the covariance matrix is calculated from the ensemble simulations. The proposed method was applied to case studies including an actual flood event occurred. It considers two situations with more idealized one by assuming continuous flood inundation depth information is available at multiple locations. The other one, which is more realistic case during such a severe flood disaster, assumes uncertain and non-continuous information is available to be assimilated. The results show that, in the first idealized situation, the large scale inundation during the flooding was estimated reasonably with RMSE effective. Nevertheless, the applications of the proposed data assimilation method demonstrated a high potential of this method for assimilating citizen collected information for real-time flood hazard mapping in the future.

Hazard characterisation of chemicals in food and diet : dose response, mechanisms and extrapolation issues

NARCIS (Netherlands)

Dybing, E.; Doe, J.; Groten, J.; Kleiner, J.; O'Brien, J.; Renwick, A.G.; Schlatter, J.; Steinberg, P.; Tritscher, A.; Walker, R.; Younes, M.

2002-01-01

Hazard characterisation of low molecular weight chemicals in food and diet generally use a no-observed-adverse-effect level (NOAEL) or a benchmark dose as the starting point. For hazards that are considered not to have thresholds for their mode of action, low-dose extrapolation and other modelling

Characterising fire hazard from temporal sequences of thermal infrared modis measurements

NARCIS (Netherlands)

Maffei, C.; Alfieri, S.M.; Menenti, M.

2012-01-01

The objective of the present research was the characterisation of fire hazard using temporal sequences of land surface temperature (LST) derived from Terra-MODIS measurements. The investigation was based on a complete sequence of MODIS LST data from 2000 to 2006 on Campania (Italy) and on a dataset

Modeling Flood Hazard Zones at the Sub-District Level with the Rational Model Integrated with GIS and Remote Sensing Approaches

Directory of Open Access Journals (Sweden)

Daniel Asare-Kyei

2015-07-01

Full Text Available Robust risk assessment requires accurate flood intensity area mapping to allow for the identification of populations and elements at risk. However, available flood maps in West Africa lack spatial variability while global datasets have resolutions too coarse to be relevant for local scale risk assessment. Consequently, local disaster managers are forced to use traditional methods such as watermarks on buildings and media reports to identify flood hazard areas. In this study, remote sensing and Geographic Information System (GIS techniques were combined with hydrological and statistical models to delineate the spatial limits of flood hazard zones in selected communities in Ghana, Burkina Faso and Benin. The approach involves estimating peak runoff concentrations at different elevations and then applying statistical methods to develop a Flood Hazard Index (FHI. Results show that about half of the study areas fall into high intensity flood zones. Empirical validation using statistical confusion matrix and the principles of Participatory GIS show that flood hazard areas could be mapped at an accuracy ranging from 77% to 81%. This was supported with local expert knowledge which accurately classified 79% of communities deemed to be highly susceptible to flood hazard. The results will assist disaster managers to reduce the risk to flood disasters at the community level where risk outcomes are first materialized.

Scale orientated analysis of river width changes due to extreme flood hazards

Directory of Open Access Journals (Sweden)

G. Krapesch

2011-08-01

Full Text Available This paper analyses the morphological effects of extreme floods (recurrence interval >100 years and examines which parameters best describe the width changes due to erosion based on 5 affected alpine gravel bed rivers in Austria. The research was based on vertical aerial photos of the rivers before and after extreme floods, hydrodynamic numerical models and cross sectional measurements supported by LiDAR data of the rivers. Average width ratios (width after/before the flood were calculated and correlated with different hydraulic parameters (specific stream power, shear stress, flow area, specific discharge. Depending on the geomorphological boundary conditions of the different rivers, a mean width ratio between 1.12 (Lech River and 3.45 (Trisanna River was determined on the reach scale. The specific stream power (SSP best predicted the mean width ratios of the rivers especially on the reach scale and sub reach scale. On the local scale more parameters have to be considered to define the "minimum morphological spatial demand of rivers", which is a crucial parameter for addressing and managing flood hazards and should be used in hazard zone plans and spatial planning.

Flood Hazard Assessment along the Western Regions of Saudi Arabia using GIS-based Morphometry and Remote Sensing Techniques

KAUST Repository

Shi, Qianwen

2014-12-01

Flash flooding, as a result of excessive rainfall in a short period, is considered as one of the worst environmental hazards in arid regions. Areas located in the western provinces of Saudi Arabia have experienced catastrophic floods. Geomorphologic evaluation of hydrographic basins provides necessary information to define basins with flood hazard potential in arid regions, especially where long-term field observations are scarce and limited. Six large basins (from North to South: Yanbu, Rabigh, Khulais, El-Qunfza, Baish and Jizan) were selected for this study because they have large surface areas and they encompass high capacity dams at their downstream areas. Geographic Information System (GIS) and remote sensing techniques were applied to conduct detailed morphometric analysis of these basins. The six basins were further divided into 203 sub-basins based on their drainage density. The morphometric parameters of the six basins and their associated 203 sub-basins were calculated to estimate the degree of flood hazard by combining normalized values of these parameters. Thus, potential flood hazard maps were produced from the estimated hazard degree. Furthermore, peak runoff discharge of the six basins and sub-basins were estimated using the Snyder Unit Hydrograph and three empirical models (Nouh’s model, Farquharson’s model and Al-Subai’s model) developed for Saudi Arabia. Additionally, recommendations for flood mitigation plans and water management schemes along these basins were further discussed.

Floods and droughts: friends or foes?

Science.gov (United States)

Prudhomme, Christel

2017-04-01

Water hazards are some of the biggest threats to lives and livelihoods globally, causing serious damages to society and infrastructure. But floods and droughts are an essential part of the hydrological regime that ensures fundamental ecosystem functions, providing natural ways to bring in nutrients, flush out pollutants and enabling soils, rivers and lakes natural biodiversity to thrive. Traditionally, floods and droughts are too often considered separately, with scientific advance in process understanding, modelling, statistical characterisation and impact assessment are often done independently, possibly delaying the development of innovative methods that could be applied to both. This talk will review some of the key characteristics of floods and droughts, highlighting differences and commonalties, losses and benefits, with the aim of identifying future key research challenges faced by both current and next generation of hydrologists.

Scoping of Flood Hazard Mapping Needs for Coos County, New Hampshire

National Research Council Canada - National Science Library

Flynn, Robert H

2006-01-01

This report was prepared by the U.S. Geological Survey (USGS) New Hampshire/Vermont Water Science Center for scoping of flood-hazard mapping needs for Coos County, New Hampshire, under Federal Emergency Management Agency (FEMA...

Scoping of Flood Hazard Mapping Needs for Belknap County, New Hampshire

National Research Council Canada - National Science Library

Flynn, Robert H

2006-01-01

This report was prepared by the U.S. Geological Survey (USGS) New Hampshire/Vermont Water Science Center for scoping of flood-hazard mapping needs for Belknap County, New Hampshire, under Federal Emergency Management Agency (FEMA...

Scoping of Flood Hazard Mapping Needs for Merrimack County, New Hampshire

National Research Council Canada - National Science Library

Flynn, Robert H

2006-01-01

This report was prepared by the U.S. Geological Survey (USGS) New Hampshire/VermontWater Science Center for scoping of flood-hazard mapping needs for Merrimack County, New Hampshire, under Federal Emergency Management Agency (FEMA...

The Atlas of Natural Hazards and Risks of Austria: first results for fluvial and pluvial floods

Science.gov (United States)

Mergili, Martin; Tader, Andreas; Glade, Thomas; Neuhold, Clemens; Stiefelmeyer, Heinz

2015-04-01

Incoherent societal adaptation to natural processes results in significant losses every year. A better knowledge of the spatial and temporal distribution of hazards and risks, and of particular hot spots in a given region or period, is essential for reducing adverse impacts. Commonly, different hazard and risk estimations are performed within individual approaches based on tailor-made concepts. This works well as long as specific cases are considered. The advantage of such a procedure is that each individual hazard and risk is addressed in the best possible manner. The drawback, however, consists in the fact that the results differ significantly in terms of quality and accuracy and therefore cannot be compared. Hence, there is a need to develop a strategy and concept which uses similar data sources of equivalent quality in order to adequately analyze the different natural hazards and risks at broader scales. The present study is aiming to develop such a platform. The project Risk:ATlas focuses on the design of an atlas visualizing the most relevant natural hazards and, in particular, possible consequences for the entire territory of Austria. Available as a web-based tool and as a printed atlas, it is seen as a key tool to improve the basis for risk reduction, risk adaptation and risk transfer. The atlas is founded on those data sets available for the entire territory of Austria at a consistent resolution and quality. A 1 m resolution DEM and the official cadastre and building register represent the core, further data sets are employed according to the requirements for each natural hazard and risk. In this contribution, the methodology and the preliminary results for fluvial and pluvial floods and their consequences to buildings for three selected test areas in different types of landscapes (rural, urban and mountainous) are presented. Flooding depths expected for annualities of 30, 100 and 300 are derived from existing data sets for fluvial floods and are computed

Real-time forecasts of flood hazard and impact: some UK experiences

Directory of Open Access Journals (Sweden)

Cole Steven J.

2016-01-01

Full Text Available Major UK floods over the last decade have motivated significant technological and scientific advances in operational flood forecasting and warning. New joint forecasting centres between the national hydrological and meteorological operating agencies have been formed that issue a daily, national Flood Guidance Statement (FGS to the emergency response community. The FGS is based on a Flood Risk Matrix approach that is a function of potential impact severity and likelihood. It has driven an increased demand for robust, accurate and timely forecast and alert information on fluvial and surface water flooding along with impact assessments. The Grid-to-Grid (G2G distributed hydrological model has been employed across Britain at a 1km resolution to support the FGS. Novel methods for linking dynamic gridded estimates of river flow and surface runoff with more detailed offline flood risk maps have been developed to obtain real-time probabilistic forecasts of potential impacts, leading to operational trials. Examples of the national-scale G2G application are provided along with case studies of forecast flood impact from (i an operational Surface Water Flooding (SWF trial during the Glasgow 2014 Commonwealth Games, (ii SWF developments under the Natural Hazards Partnership over England & Wales, and (iii fluvial applications in Scotland.

Maximum flood hazard assessment for OPG's deep geologic repository for low and intermediate level waste

International Nuclear Information System (INIS)

Nimmrichter, P.; McClintock, J.; Peng, J.; Leung, H.

2011-01-01

Ontario Power Generation (OPG) has entered a process to seek Environmental Assessment and licensing approvals to construct a Deep Geologic Repository (DGR) for Low and Intermediate Level Radioactive Waste (L&ILW) near the existing Western Waste Management Facility (WWMF) at the Bruce nuclear site in the Municipality of Kincardine, Ontario. In support of the design of the proposed DGR project, maximum flood stages were estimated for potential flood hazard risks associated with coastal, riverine and direct precipitation flooding. The estimation of lake/coastal flooding for the Bruce nuclear site considered potential extreme water levels in Lake Huron, storm surge and seiche, wind waves, and tsunamis. The riverine flood hazard assessment considered the Probable Maximum Flood (PMF) within the local watersheds, and within local drainage areas that will be directly impacted by the site development. A series of hydraulic models were developed, based on DGR project site grading and ditching, to assess the impact of a Probable Maximum Precipitation (PMP) occurring directly at the DGR site. Overall, this flood assessment concluded there is no potential for lake or riverine based flooding and the DGR area is not affected by tsunamis. However, it was also concluded from the results of this analysis that the PMF in proximity to the critical DGR operational areas and infrastructure would be higher than the proposed elevation of the entrance to the underground works. This paper provides an overview of the assessment of potential flood hazard risks associated with coastal, riverine and direct precipitation flooding that was completed for the DGR development. (author)

Has dyke development in the Vietnamese Mekong Delta shifted flood hazard downstream?

Science.gov (United States)

Van Khanh Triet, Nguyen; Viet Dung, Nguyen; Fujii, Hideto; Kummu, Matti; Merz, Bruno; Apel, Heiko

2017-08-01

In the Vietnamese part of the Mekong Delta (VMD) the areas with three rice crops per year have been expanded rapidly during the last 15 years. Paddy-rice cultivation during the flood season has been made possible by implementing high-dyke flood defenses and flood control structures. However, there are widespread claims that the high-dyke system has increased water levels in downstream areas. Our study aims at resolving this issue by attributing observed changes in flood characteristics to high-dyke construction and other possible causes. Maximum water levels and duration above the flood alarm level are analysed for gradual trends and step changes at different discharge gauges. Strong and robust increasing trends of peak water levels and duration downstream of the high-dyke areas are found with a step change in 2000/2001, i.e. immediately after the disastrous flood which initiated the high-dyke development. These changes are in contrast to the negative trends detected at stations upstream of the high-dyke areas. This spatially different behaviour of changes in flood characteristics seems to support the public claims. To separate the impact of the high-dyke development from the impact of the other drivers - i.e. changes in the flood hydrograph entering the Mekong Delta, and changes in the tidal dynamics - hydraulic model simulations of the two recent large flood events in 2000 and 2011 are performed. The hydraulic model is run for a set of scenarios whereas the different drivers are interchanged. The simulations reveal that for the central VMD an increase of 9-13 cm in flood peak and 15 days in duration can be attributed to high-dyke development. However, for this area the tidal dynamics have an even larger effect in the range of 19-32 cm. However, the relative contributions of the three drivers of change vary in space across the delta. In summary, our study confirms the claims that the high-dyke development has raised the flood hazard downstream. However, it is not

Open Source Web-Based Solutions for Disseminating and Analyzing Flood Hazard Information at the Community Level

Science.gov (United States)

Santillan, M. M.-M.; Santillan, J. R.; Morales, E. M. O.

2017-09-01

We discuss in this paper the development, including the features and functionalities, of an open source web-based flood hazard information dissemination and analytical system called "Flood EViDEns". Flood EViDEns is short for "Flood Event Visualization and Damage Estimations", an application that was developed by the Caraga State University to address the needs of local disaster managers in the Caraga Region in Mindanao, Philippines in accessing timely and relevant flood hazard information before, during and after the occurrence of flood disasters at the community (i.e., barangay and household) level. The web application made use of various free/open source web mapping and visualization technologies (GeoServer, GeoDjango, OpenLayers, Bootstrap), various geospatial datasets including LiDAR-derived elevation and information products, hydro-meteorological data, and flood simulation models to visualize various scenarios of flooding and its associated damages to infrastructures. The Flood EViDEns application facilitates the release and utilization of this flood-related information through a user-friendly front end interface consisting of web map and tables. A public version of the application can be accessed at http://121.97.192.11:8082/. The application is currently expanded to cover additional sites in Mindanao, Philippines through the "Geo-informatics for the Systematic Assessment of Flood Effects and Risks for a Resilient Mindanao" or the "Geo-SAFER Mindanao" Program.

The relevance of flood hazards and impacts in Turkey: What can be learned from different disaster loss databases?

Science.gov (United States)

Koc, Gamze; Thieken, Annegret H.

2016-04-01

Despite technological development, better data and considerable efforts to reduce the impacts of natural hazards over the last two decades, natural disasters inflicted losses have caused enormous human and economic damages in Turkey. In particular earthquakes and flooding have caused enormous human and economic losses that occasionally amounted to 3 to 4% of the gross national product of Turkey (Genç, 2007). While there is a large body of literature on earthquake hazards and risks in Turkey, comparatively little is known about flood hazards and risks. Therefore, this study is aimed at investigating flood patterns, intensities and impacts, also providing an overview of the temporal and spatial distribution of flood losses by analysing different databases on disaster losses throughout Turkey. As input for more detailed event analyses, an additional aim is to retrieve the most severe flood events in the period between 1960 and 2014 from the databases. In general, data on disaster impacts are scarce in comparison to other scientific fields in natural hazard research, although the lack of reliable, consistent and comparable data is seen as a major obstacle for effective and long-term loss prevention. Currently, only a few data sets, especially the emergency events database EM-DAT (www.emdat.be) hosted and maintained by the Centre for Research on the Epidemiology of Disasters (CRED) since 1988, are publicly accessible and have become widely used to describe trends in disaster losses. However, loss data are subjected to various biases (Gall et al. 2009). Since Turkey is in the favourable position of having a distinct national disaster database since 2009, i.e. the Turkey Disaster Data Base (TABB), there is the unique opportunity to investigate flood impacts in Turkey in more detail as well as to identify biases and underlying reasons for mismatches with EM-DAT. To compare these two databases, the events of the two databases were reclassified by using the IRDR peril

Regional flood hazard assessment of the Paducah and Portsmouth Gaseous Diffusion Plants

International Nuclear Information System (INIS)

Johnson, R.O.; Wang, J.C.; Lee, D.W.

1991-01-01

Regional flood-hazard assessments performed for the Paducah and Portsmouth Gaseous Diffusion Plants are reviewed, compared, and contrasted to determine the relationship of probable maximum flood methodology with respect to US Department of Energy design and evaluation guidelines. The Paducah assessment was carried out using probable minimum flood methodology, while the Portsmouth assessment utilized probabilistic techniques. Results indicated that regional flooding along nearby rivers would not inundate either plant, and that the guidelines were satisfied. A comparison of results indicated that the probable minimum flood recurrence interval associated with the Paducah assessment exceeded the 10,000-year requirement of the guidelines, while recurrence intervals obtained in the Portsmouth assessment could be above or below 10,000 years depending on the choice of the probabilistic model used to perform the assessment. It was concluded, based on an analysis of two data points, that smaller watersheds driven by single event storms could be assessed using probabilistic techniques, while probable maximum flood methodology could be applied to larger drainage basins flooded by storm sequences

Report 2: Guidance document on practices to model and implement external flooding hazards in extended PSA

International Nuclear Information System (INIS)

Rebour, V.; Georgescu, G.; Leteinturier, D.; Raimond, E.; La Rovere, S.; Bernadara, P.; Vasseur, D.; Brinkman, H.; Groudev, P.; Ivanov, I.; Turschmann, M.; Sperbeck, S.; Potempski, S.; Hirata, K.; Kumar, Manorma

2016-01-01

This report provides a review of existing practices to model and implement external flooding hazards in existing level 1 PSA. The objective is to identify good practices on the modelling of initiating events (internal and external hazards) with a perspective of development of extended PSA and implementation of external events modelling in extended L1 PSA, its limitations/difficulties as far as possible. The views presented in this report are based on the ASAMPSA-E partners' experience and available publications. The report includes discussions on the following issues: - how to structure a L1 PSA for external flooding events, - information needed from geosciences in terms of hazards modelling and to build relevant modelling for PSA, - how to define and model the impact of each flooding event on SSCs with distinction between the flooding protective structures and devices and the effect of protection failures on other SSCs, - how to identify and model the common cause failures in one reactor or between several reactors, - how to apply HRA methodology for external flooding events, - how to credit additional emergency response (post-Fukushima measures like mobile equipment), - how to address the specific issues of L2 PSA, - how to perform and present risk quantification. (authors)

Efficient pan-European river flood hazard modelling through a combination of statistical and physical models

NARCIS (Netherlands)

Paprotny, D.; Morales Napoles, O.; Jonkman, S.N.

2017-01-01

Flood hazard is currently being researched on continental and global scales, using models of increasing complexity. In this paper we investigate a different, simplified approach, which combines statistical and physical models in place of conventional rainfall-run-off models to carry out flood

Living with Familiar Hazards: Flood Experiences and Human Vulnerability in Accra, Ghana

Directory of Open Access Journals (Sweden)

Dacosta Aboagye

2012-10-01

Full Text Available The paper explores demographic characteristics, migration history, and impact of flooding on households and communities. The main objective is to explore the different ways in which floods impact households and communities in Accra. Specifically, the paper analyzes how floods alter the set of resources available to households and communities. The results indicate that urbanization and governmental policies have rendered more people, especially the poor and recent migrants, homeless. These homeless people have become more vulnerable to flooding than the average Accra resident. The results also show that the homeless community contrast with the fixed community in terms of socio-economic characteristics, degree of social cohesion, and physical location. The paper concludes that the unchanging pattern of vulnerability shows the inability of a society to cope and adjust to familiar hazards.

Flood Hazard Recurrence Frequencies for A-, K- and L-Areas, and Revised Frequencies for C-, F-, E-, S-, H-, Y- and Z-Areas

International Nuclear Information System (INIS)

Chen, K.F.

2000-01-01

Department of Energy (DOE) Order 420.1, Facility Safety, outlines the requirements for Natural Phenomena Hazard (NPH) mitigation for new and existing DOE facilities. The NPH considered in this report is flooding. The facility-specific probabilistic flood hazard curve defines as a function of water elevation the annual probability of occurrence or the return period in years. Based on facility-specific probabilistic flood hazard curves and the nature of facility operations (e.g., involving hazardous or radioactive materials), facility managers can design permanent or temporary devices to prevent the propagation of flood on site, and develop emergency preparedness plans to mitigate the consequences of floods. Methods were developed to determine the probabilistic flood elevation curves for Savannah River Site (SRS) facilities. This report presents the methods used to determine the probabilistic flood elevation curves for A-, K-, C-, F-, E-, H-, S-, Y-, Z- and L-Areas

Has dyke development in the Vietnamese Mekong Delta shifted flood hazard downstream?

Directory of Open Access Journals (Sweden)

N. V. K. Triet

2017-08-01

hazard downstream. However, it is not the only and not the most important driver of the observed changes. It has to be noted that changes in tidal levels caused by sea level rise in combination with the widely observed land subsidence and the temporal coincidence of high water levels and spring tides have even larger impacts. It is recommended to develop flood risk management strategies using the high-dyke areas as retention zones to mitigate the flood hazard downstream.

Flood Hazard Mapping Assessment for El-Awali River Catchment-Lebanon

Science.gov (United States)

Hdeib, Rouya; Abdallah, Chadi; Moussa, Roger; Hijazi, Samar

2016-04-01

River flooding prediction and flood forecasting has become an essential stage in the major flood mitigation plans worldwide. Delineation of floodplains resulting from a river flooding event requires coupling between a Hydrological rainfall-runoff model to calculate the resulting outflows of the catchment and a hydraulic model to calculate the corresponding water surface profiles along the river main course. In this study several methods were applied to predict the flood discharge of El-Awali River using the available historical data and gauging records and by conducting several site visits. The HEC-HMS Rainfall-Runoff model was built and applied to calculate the flood hydrographs along several outlets on El-Awali River and calibrated using the storm that took place on January 2013 and caused flooding of the major Lebanese rivers and by conducting additional site visits to calculate proper river sections and record witnesses of the locals. The Hydraulic HEC-RAS model was then applied to calculate the corresponding water surface profiles along El-Awali River main reach. Floodplain delineation and Hazard mapping for 10,50 and 100 years return periods was performed using the Watershed Modeling System WMS. The results first show an underestimation of the flood discharge recorded by the operating gauge stations on El-Awali River, whereas, the discharge of the 100 years flood may reach up to 506 m3/s compared by lower values calculated using the traditional discharge estimation methods. Second any flooding of El-Awali River may be catastrophic especially to the coastal part of the catchment and can cause tragic losses in agricultural lands and properties. Last a major floodplain was noticed in Marj Bisri village this floodplain can reach more than 200 meters in width. Overall, performance was good and the Rainfall-Runoff model can provide valuable information about flows especially on ungauged points and can perform a great aid for the floodplain delineation and flood

Flood Hazard Mapping by Using Geographic Information System and Hydraulic Model: Mert River, Samsun, Turkey

Directory of Open Access Journals (Sweden)

Vahdettin Demir

2016-01-01

Full Text Available In this study, flood hazard maps were prepared for the Mert River Basin, Samsun, Turkey, by using GIS and Hydrologic Engineering Centers River Analysis System (HEC-RAS. In this river basin, human life losses and a significant amount of property damages were experienced in 2012 flood. The preparation of flood risk maps employed in the study includes the following steps: (1 digitization of topographical data and preparation of digital elevation model using ArcGIS, (2 simulation of flood lows of different return periods using a hydraulic model (HEC-RAS, and (3 preparation of flood risk maps by integrating the results of (1 and (2.

Assessing inundation hazards to nuclear powerplant sites using geologically extended histories of riverine floods, tsunamis, and storm surges

Science.gov (United States)

O'Connor, Jim; Atwater, Brian F.; Cohn, Timothy A.; Cronin, Thomas M.; Keith, Mackenzie K.; Smith, Christopher G.; Mason, Jr., Robert R.

2014-01-01

Most nuclear powerplants in the United States are near rivers, large lakes, or oceans. As evident from the Fukushima Daiichi, Japan, disaster of 2011, these water bodies pose inundation threats. Geologic records can extend knowledge of rare hazards from flooding, storm surges, and tsunamis. This knowledge can aid in assessing the safety of critical structures such as dams and energy plants, for which even remotely possible hazards are pertinent. Quantitative analysis of inundation from geologic records perhaps is most developed for and applied to riverine flood hazards, but because of recent natural disasters, geologic investigations also are now used widely for understanding tsunami hazards and coastal storm surges.

The Bisagno stream catchment (Genoa, Italy) and its major floods: geomorphic and land use variations in the last three centuries

Science.gov (United States)

Faccini, Francesco; Paliaga, Guido; Piana, Pietro; Sacchini, Alessandro; Watkins, Charles

2016-11-01

The city of Genoa (Liguria, Italy) and the Bisagno Valley are affected by frequent floods, often with loss of human lives. Historically characterised by high flood hazards, the Bisagno Valley was recently affected by a flood event on 9 October 2014, less than three years after the tragic flood event of 4 November 2011 when six people died, including two children. In the last 50 years, four destructive floods occurred in the Bisagno Valley, in addition to some other events that caused significant damage and economic losses. This paper examines the three largest flood events in terms of intensity and ground effects which affected the Bisagno Valley in the last three centuries: the flood of 25 October 1822, well documented by contemporary sources, the flood of 8 October 1970, undoubtedly the most tragic on record, and the very recent event of 9 October 2014. For this purpose scientific and historical-geographical methodologies were adopted, the latter particularly useful for the reconstruction of the flood event of 1822 and the landscape history of the Bisagno Valley in the nineteenth century. This comparison shows that the Bisagno Valley is characterised by climatic and landform features that have been making the flood events historically common in the area. However, recent climate change and land-use variations, including some major modifications of the catchment basin, have progressively determined a decrease of the concentration time and an increase of runoff, solid transport, and flood hazard. Consequently, in recent decades a growth in the number of flood events occurred, to the extent that the Bisagno today is a famous case study on an international scale.

Torrential Flood Hazards Assessment, Management, And Mitigation, In Wadi Aday, Muscat Area, Sultanate Of Oman, A GIS and RS Approach

International Nuclear Information System (INIS)

SalehI, A.S.; AI-Hatrushi, S.M.

2009-01-01

Flash flood hazard of Wadi Aday threaten human activities in an important urban area of Muscat City, the capital of Sultanate of Oman. To evaluate and mitigate these floods; Remote Sensing (IKONOS Images), Topographic and Cadastral maps, data of rainfall, floods and other data sources have been used under a GIS environment and manipulated. The study determined the areas under the flood risk, and clarified the risk class and degree for each of human activities object in the lower part of Wadi Aday. In order to mitigate the flood hazards, and to utilize the floods water in such extreme hot desert; the study suggested: establishing two dams and artificial channel added to some methods that reduce the erosion on canyon reach road

Comparison between changes in flood hazard and risk in Spain using historical information

Science.gov (United States)

Llasat, Maria-Carmen; Mediero, Luis; Garrote, Luis; Gilabert, Joan

2015-04-01

Recently, the COST Action ES0901 "European procedures for flood frequency estimation (FloodFreq)" had as objective "the comparison and evaluation of methods for flood frequency estimation under the various climatologic and geographic conditions found in Europe". It was highlighted the improvement of regional analyses on at-site estimates, in terms of the uncertainty of quantile estimates. In the case of Spain, a regional analysis was carried out at a national scale, which allows identifying the flow threshold corresponding to a given return period from the observed flow series recorded at a gauging station. In addition, Mediero et al. (2014) studied the possible influence of non-stationarity on flood series for the period 1942-2009. In parallel, Barnolas and Llasat (2007), among others, collected documentary information of catastrophic flood events in Spain for the last centuries. Traditionally, the first approach ("top-down") usually identifies a flood as catastrophic, when its exceeds the 500-year return period flood. However, the second one ("bottom-up approach") accounts for flood damages (Llasat et al, 2005). This study presents a comparison between both approaches, discussing the potential factors that can lead to discrepancies between them, as well as accounting for information about major changes experienced in the catchment that could lead to changes in flood hazard and risk.

Challenges in understanding, modelling, and mitigating Lake Outburst Flood Hazard: experiences from Central Asia

Science.gov (United States)

Mergili, Martin; Schneider, Demian; Andres, Norina; Worni, Raphael; Gruber, Fabian; Schneider, Jean F.

2010-05-01

Lake Outburst Floods can evolve from complex process chains like avalanches of rock or ice that produce flood waves in a lake which may overtop and eventually breach glacial, morainic, landslide, or artificial dams. Rising lake levels can lead to progressive incision and destabilization of a dam, to enhanced ground water flow (piping), or even to hydrostatic failure of ice dams which can cause sudden outflow of accumulated water. These events often have a highly destructive potential because a large amount of water is released in a short time, with a high capacity to erode loose debris, leading to a powerful debris flow with a long travel distance. The best-known example of a lake outburst flood is the Vajont event (Northern Italy, 1963), where a landslide rushed into an artificial lake which spilled over and caused a flood leading to almost 2000 fatalities. Hazards from the failure of landslide dams are often (not always) fairly manageable: most breaches occur in the first few days or weeks after the landslide event and the rapid construction of a spillway - though problematic - has solved some hazardous situations (e.g. in the case of Hattian landslide in 2005 in Pakistan). Older dams, like Usoi dam (Lake Sarez) in Tajikistan, are usually fairly stable, though landsildes into the lakes may create floodwaves overtopping and eventually weakening the dams. The analysis and the mitigation of glacial lake outburst flood (GLOF) hazard remains a challenge. A number of GLOFs resulting in fatalities and severe damage have occurred during the previous decades, particularly in the Himalayas and in the mountains of Central Asia (Pamir, Tien Shan). The source area is usually far away from the area of impact and events occur at very long intervals or as singularities, so that the population at risk is usually not prepared. Even though potentially hazardous lakes can be identified relatively easily with remote sensing and field work, modeling and predicting of GLOFs (and also

Flood Hazards - A National Threat

Science.gov (United States)

,

2006-01-01

In the late summer of 2005, the remarkable flooding brought by Hurricane Katrina, which caused more than $200 billion in losses, constituted the costliest natural disaster in U.S. history. However, even in typical years, flooding causes billions of dollars in damage and threatens lives and property in every State. Natural processes, such as hurricanes, weather systems, and snowmelt, can cause floods. Failure of levees and dams and inadequate drainage in urban areas can also result in flooding. On average, floods kill about 140 people each year and cause $6 billion in property damage. Although loss of life to floods during the past half-century has declined, mostly because of improved warning systems, economic losses have continued to rise due to increased urbanization and coastal development.

Toward a coupled Hazard-Vulnerability Tool for Flash Flood Impacts Prediction

Science.gov (United States)

Terti, Galateia; Ruin, Isabelle; Anquetin, Sandrine; Gourley, Jonathan J.

2015-04-01

Flash floods (FF) are high-impact, catastrophic events that result from the intersection of hydrometeorological extremes and society at small space-time scales, generally on the order of minutes to hours. Because FF events are generally localized in space and time, they are very difficult to forecast with precision and can subsequently leave people uninformed and subject to surprise in the midst of their daily activities (e.g., commuting to work). In Europe, FFs are the main source of natural hazard fatalities, although they affect smaller areas than riverine flooding. In the US, also, flash flooding is the leading cause of weather-related deaths most years, with some 200 annual fatalities. There were 954 fatalities and approximately 31 billion U.S. dollars of property damage due to floods and flash floods from 1995 to 2012 in the US. For forecasters and emergency managers the prediction of and subsequent response to impacts due to such a sudden onset and localized event remains a challenge. This research is motivated by the hypothesis that the intersection of the spatio-temporal context of the hazard with the distribution of people and their characteristics across space and time reveals different paths of vulnerability. We argue that vulnerability and the dominant impact type varies dynamically throughout the day and week according to the location under concern. Thus, indices are appropriate to develop and provide, for example, vehicle-related impacts on active population being focused on the road network during morning or evening rush hours. This study describes the methodological developments of our approach and applies our hypothesis to the case of the June 14th, 2010 flash flood event in the Oklahoma City area (Oklahoma, US). Social (i.e. population socio-economic profile), exposure (i.e. population distribution, land use), and physical (i.e. built and natural environment) data are used to compose different vulnerability products based on the forecast location

A hydro-sedimentary modeling system for flash flood propagation and hazard estimation under different agricultural practices

Science.gov (United States)

Kourgialas, N. N.; Karatzas, G. P.

2014-03-01

A modeling system for the estimation of flash flood flow velocity and sediment transport is developed in this study. The system comprises three components: (a) a modeling framework based on the hydrological model HSPF, (b) the hydrodynamic module of the hydraulic model MIKE 11 (quasi-2-D), and (c) the advection-dispersion module of MIKE 11 as a sediment transport model. An important parameter in hydraulic modeling is the Manning's coefficient, an indicator of the channel resistance which is directly dependent on riparian vegetation changes. Riparian vegetation's effect on flood propagation parameters such as water depth (inundation), discharge, flow velocity, and sediment transport load is investigated in this study. Based on the obtained results, when the weed-cutting percentage is increased, the flood wave depth decreases while flow discharge, velocity and sediment transport load increase. The proposed modeling system is used to evaluate and illustrate the flood hazard for different riparian vegetation cutting scenarios. For the estimation of flood hazard, a combination of the flood propagation characteristics of water depth, flow velocity and sediment load was used. Next, a well-balanced selection of the most appropriate agricultural cutting practices of riparian vegetation was performed. Ultimately, the model results obtained for different agricultural cutting practice scenarios can be employed to create flood protection measures for flood-prone areas. The proposed methodology was applied to the downstream part of a small Mediterranean river basin in Crete, Greece.

GIS-modelling of the spatial variability of flash flood hazard in Abu Dabbab catchment, Red Sea Region, Egypt

Directory of Open Access Journals (Sweden)

Islam Abou El-Magd

2010-06-01

Full Text Available In the mountainous area of the Red Sea region in southeastern Egypt, the development of new mining activities or/and domestic infrastructures require reliable and accurate information about natural hazards particularly flash flood. This paper presents the assessment of flash flood hazards in the Abu Dabbab drainage basin. Remotely sensed data were used to delineate the alluvial active channels, which were integrated with morphometric parameters extracted from digital elevation models (DEM into geographical information systems (GIS to construct a hydrological model that provides estimates about the amount of surface runoff as well as the magnitude of flash floods. The peak discharge is randomly varied at different cross-sections along the main channel. Under consistent 10 mm rainfall event, the selected cross-section in middle of the main channel is prone to maximum water depth at 80 cm, which decreases to nearly 30 cm at the outlet due to transmission loss. The estimation of spatial variability of flow parameters within the catchment at different confluences of the constituting sub-catchments can be considered and used in planning for engineering foundations and linear infrastructures with the least flash flood hazard. Such information would, indeed, help decision makers and planning to minimize such hazards.

Landslide and glacial lake outburst flood hazard in the Chucchún river basin, Cordillera Blanca, Peru

Czech Academy of Sciences Publication Activity Database

Klimeš, Jan; Vilímek, V.; Benešová, M.

2015-01-01

Roč. 50, č. 2 (2015), s. 173-180 ISSN 0300-5402 R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : landslide hazard * GLOFs * flood hazard * Cordillera Blanca * Peru Subject RIV: DE - Earth Magnetism, Geodesy, Geography

The hostel or the warehouse? Spatiotemporal exposure assessment for natural hazards

Science.gov (United States)

Fuchs, S.; Keiler, M.; Zischg, A.

2015-04-01

A spatially explicit object-based temporal assessment of buildings and citizens exposed to natural hazards in Austria is presented, including elements at risk to river flooding, torrential flooding, and snow avalanches. It is shown that the repeatedly-stated assumption of increasing losses due to continued population growth and related increase in assets has to be opposed to the local development of building stock. While some regions have shown a clearly above-average increase in assets, other regions were characterised by a below-average development. This mirrors the topography of the country, but also the different economic activities. While hotels and hostels are extraordinary prone to mountain hazards, commercial buildings as well as buildings used for recreation purpose are considerably exposed to river flooding. Residential buildings have shown an average exposure, compared to the amount of buildings of this type in the overall building stock. In sum, around 5% of all buildings are exposed to mountain hazards, and around 9% to river flooding, with around 1% of the buildings stock being multi-exposed. It is shown that the dynamics of elements at risk exposed have a time lag once land use regulations are enforced, and it is concluded that an object-based assessment has clear advantages compared to the assessment using aggregated land use data.

The use of historical data for the characterisation of multiple damaging hydrogeological events

Directory of Open Access Journals (Sweden)

O. Petrucci

2003-01-01

Full Text Available Landslides, floods and secondary floods (hereinafter called phenomena triggered by rainfall and causing extensive damage are reviewed in this paper. Damaging Hydrogeological Events (DHEs are defined as the occurrence of one or more simultaneous aforementioned phenomena. A method for the characterisation of DHEs based upon historic data is proposed. The method is aimed at assessing DHE-related hazard in terms of recurrence, severity, damage, and extent of the affected area. Using GIS, the DHEs historical and climatic data collection, the geomorphological and hydrogeological characterisation of the hit areas, the characterisation of induced damage, the evaluation of triggering rainfall return period and critical duration of each DHE were carried out. The approach was applied to a test site in Southern Italy (Calabria for validation purposes. A database was set up including data from 24 events which have occurred during an 80-year period. The spatial distribution of phenomena was analysed together with the return period of cumulative rainfall. The trend of the occurred phenomena was also compared with the climatic trend. Four main types of Damaging Hydrogeological Events were identified in the study area.

Climate change and flood hazard: Evaluation of the SCHADEX methodology in a non-stationary context

International Nuclear Information System (INIS)

Brigode, Pierre

2013-01-01

Since 2006, Electricite de France (EDF) applies a new hydro-climatological approach of extreme rainfall and flood predetermination - the SCHADEX method - for the design of dam spillways. In a context of potential increase of extreme event intensity and frequency due to climate change, the use of the SCHADEX method in non-stationary conditions is a main interest topic for EDF hydrologists. Thus, the scientific goal of this Ph.D. thesis work has been to evaluate the ability of the SCHADEX method to take into account future climate simulations for the estimation of future extreme floods. The recognized inabilities of climate models and down-scaling methods to simulate (extreme) rainfall distribution at the catchment-scale have been avoided, by developing and testing new methodological approaches. Moreover, the decomposition of the flood-producing factors proposed by the SCHADEX method has been used for considering different simulated climatic evolutions and for quantifying the relative impact of these factors on the extreme flood estimation. First, the SCHADEX method has been applied in present time over different climatic contexts (France, Austria, Canada and Norway), thanks to several colorations with academic and industrial partners. A sensitivity analysis allowed to quantify the extreme flood estimation sensitivity to rainfall hazard, catchment saturation hazard and rainfall-runoff transformation, independently. The results showed a large sensitivity of SCHADEX flood estimations to the rainfall hazard and to the rainfall-runoff transformation. Using the sensitivity analysis results, tests have been done in order to estimate the future evolution of 'key' variables previously identified. New climate model outputs (done within the CMIP5 project) have been analyzed and used for determining future frequency of rainfall events and future catchment saturation conditions. Considering these simulated evolutions within the SCHADEX method lead to a significant decrease of

Flood Hazard Mapping using Hydraulic Model and GIS: A Case Study in Mandalay City, Myanmar

Directory of Open Access Journals (Sweden)

Kyu Kyu Sein

2016-01-01

Full Text Available This paper presents the use of flood frequency analysis integrating with 1D Hydraulic model (HECRAS and Geographic Information System (GIS to prepare flood hazard maps of different return periods in Ayeyarwady River at Mandalay City in Myanmar. Gumbel’s distribution was used to calculate the flood peak of different return periods, namely, 10 years, 20 years, 50 years, and 100 years. The flood peak from frequency analysis were input into HEC-RAS model to find the corresponding flood level and extents in the study area. The model results were used in integrating with ArcGIS to generate flood plain maps. Flood depths and extents have been identified through flood plain maps. Analysis of 100 years return period flood plain map indicated that 157.88 km2 with the percentage of 17.54% is likely to be inundated. The predicted flood depth ranges varies from greater than 0 to 24 m in the flood plains and on the river. The range between 3 to 5 m were identified in the urban area of Chanayetharzan, Patheingyi, and Amarapua Townships. The highest inundated area was 85 km2 in the Amarapura Township.

FLOOD HAZARD MAP IN THE CITY OF BATNA (ALGERIA BY HYDRAULIC MODELING APPROCH

Directory of Open Access Journals (Sweden)

Guellouh SAMI

2016-06-01

Full Text Available In the light of the global climatic changes that appear to influence the frequency and the intensity of floods, and whose damages are still growing; understanding the hydrological processes, their spatiotemporal setting and their extreme shape, became a paramount concern to local communities in forecasting terms. The aim of this study is to map the floods hazard using a hydraulic modeling method. In fact, using the operating Geographic Information System (GIS, would allow us to perform a more detailed spatial analysis about the extent of the flooding risk, through the approval of the hydraulic modeling programs in different frequencies. Based on the results of this analysis, decision makers can implement a strategy of risk management related to rivers overflowing through the city of Batna.

Modelling Inland Flood Events for Hazard Maps in Taiwan

Science.gov (United States)

Ghosh, S.; Nzerem, K.; Sassi, M.; Hilberts, A.; Assteerawatt, A.; Tillmanns, S.; Mathur, P.; Mitas, C.; Rafique, F.

2015-12-01

Taiwan experiences significant inland flooding, driven by torrential rainfall from plum rain storms and typhoons during summer and fall. From last 13 to 16 years data, 3,000 buildings were damaged by such floods annually with a loss US$0.41 billion (Water Resources Agency). This long, narrow island nation with mostly hilly/mountainous topography is located at tropical-subtropical zone with annual average typhoon-hit-frequency of 3-4 (Central Weather Bureau) and annual average precipitation of 2502mm (WRA) - 2.5 times of the world's average. Spatial and temporal distributions of countrywide precipitation are uneven, with very high local extreme rainfall intensities. Annual average precipitation is 3000-5000mm in the mountainous regions, 78% of it falls in May-October, and the 1-hour to 3-day maximum rainfall are about 85 to 93% of the world records (WRA). Rivers in Taiwan are short with small upstream areas and high runoff coefficients of watersheds. These rivers have the steepest slopes, the shortest response time with rapid flows, and the largest peak flows as well as specific flood peak discharge (WRA) in the world. RMS has recently developed a countrywide inland flood model for Taiwan, producing hazard return period maps at 1arcsec grid resolution. These can be the basis for evaluating and managing flood risk, its economic impacts, and insured flood losses. The model is initiated with sub-daily historical meteorological forcings and calibrated to daily discharge observations at about 50 river gauges over the period 2003-2013. Simulations of hydrologic processes, via rainfall-runoff and routing models, are subsequently performed based on a 10000 year set of stochastic forcing. The rainfall-runoff model is physically based continuous, semi-distributed model for catchment hydrology. The 1-D wave propagation hydraulic model considers catchment runoff in routing and describes large-scale transport processes along the river. It also accounts for reservoir storage

FLOOD MENACE IN KADUNA METROPOLIS: IMPACTS ...

African Journals Online (AJOL)

Dr A.B.Ahmed

damage, causes of flooding, human response to flooding and severity of ... from moving out. Source of ... Man responds to flood hazards through adjustment, flood abatement ... action to minimize or ameliorate flood hazards; flood abatement.

Combining criteria for delineating lahar- and flash-flood-prone hazard and risk zones for the city of Arequipa, Peru

OpenAIRE

Thouret , Jean-Claude; Enjolras , G.; Martelli , K.; Santoni , O.; Luque , A.; Nagata , M.; Arguedas , A.; Macedo , L.

2013-01-01

Arequipa, the second largest city in Peru, is exposed to many natural hazards, most notably earthquakes, volcanic eruptions, landslides, lahars (volcanic debris flows), and flash floods. Of these, lahars and flash floods, triggered by occasional torrential rainfall, pose the most frequently occurring hazards that can affect the city and its environs, in particular the areas containing low-income neighbourhoods. This paper presents and discusses criteria for delineating areas prone to flash fl...

High-resolution marine flood modelling coupling overflow and overtopping processes: framing the hazard based on historical and statistical approaches

Science.gov (United States)

Nicolae Lerma, Alexandre; Bulteau, Thomas; Elineau, Sylvain; Paris, François; Durand, Paul; Anselme, Brice; Pedreros, Rodrigo

2018-01-01

A modelling chain was implemented in order to propose a realistic appraisal of the risk in coastal areas affected by overflowing as well as overtopping processes. Simulations are performed through a nested downscaling strategy from regional to local scale at high spatial resolution with explicit buildings, urban structures such as sea front walls and hydraulic structures liable to affect the propagation of water in urban areas. Validation of the model performance is based on hard and soft available data analysis and conversion of qualitative to quantitative information to reconstruct the area affected by flooding and the succession of events during two recent storms. Two joint probability approaches (joint exceedance contour and environmental contour) are used to define 100-year offshore conditions scenarios and to investigate the flood response to each scenario in terms of (1) maximum spatial extent of flooded areas, (2) volumes of water propagation inland and (3) water level in flooded areas. Scenarios of sea level rise are also considered in order to evaluate the potential hazard evolution. Our simulations show that for a maximising 100-year hazard scenario, for the municipality as a whole, 38 % of the affected zones are prone to overflow flooding and 62 % to flooding by propagation of overtopping water volume along the seafront. Results also reveal that for the two kinds of statistic scenarios a difference of about 5 % in the forcing conditions (water level, wave height and period) can produce significant differences in terms of flooding like +13.5 % of water volumes propagating inland or +11.3 % of affected surfaces. In some areas, flood response appears to be very sensitive to the chosen scenario with differences of 0.3 to 0.5 m in water level. The developed approach enables one to frame the 100-year hazard and to characterize spatially the robustness or the uncertainty over the results. Considering a 100-year scenario with mean sea level rise (0.6 m), hazard

A Bayesian-Based System to Assess Wave-Driven Flooding Hazards on Coral Reef-Lined Coasts

Science.gov (United States)

Pearson, S. G.; Storlazzi, C. D.; van Dongeren, A. R.; Tissier, M. F. S.; Reniers, A. J. H. M.

2017-12-01

Many low-elevation, coral reef-lined, tropical coasts are vulnerable to the effects of climate change, sea level rise, and wave-induced flooding. The considerable morphological diversity of these coasts and the variability of the hydrodynamic forcing that they are exposed to make predicting wave-induced flooding a challenge. A process-based wave-resolving hydrodynamic model (XBeach Non-Hydrostatic, "XBNH") was used to create a large synthetic database for use in a "Bayesian Estimator for Wave Attack in Reef Environments" (BEWARE), relating incident hydrodynamics and coral reef geomorphology to coastal flooding hazards on reef-lined coasts. Building on previous work, BEWARE improves system understanding of reef hydrodynamics by examining the intrinsic reef and extrinsic forcing factors controlling runup and flooding on reef-lined coasts. The Bayesian estimator has high predictive skill for the XBNH model outputs that are flooding indicators, and was validated for a number of available field cases. It was found that, in order to accurately predict flooding hazards, water depth over the reef flat, incident wave conditions, and reef flat width are the most essential factors, whereas other factors such as beach slope and bed friction due to the presence or absence of corals are less important. BEWARE is a potentially powerful tool for use in early warning systems or risk assessment studies, and can be used to make projections about how wave-induced flooding on coral reef-lined coasts may change due to climate change.Plain Language SummaryLow-lying tropical coasts fronted by coral reefs are threatened by the effects of climate change, sea level rise, and flooding caused by waves. However, the reefs on these coasts differ widely in their shape, size, and physical characteristics; the wave and water level conditions affecting these coastlines also vary in space and time. These factors make it difficult to predict flooding caused by waves along coral reef-lined coasts. We

A spatiotemporal multi-hazard exposure assessment based on property data

Science.gov (United States)

Fuchs, Sven; Keiler, Margreth; Zischg, Andreas

2016-04-01

The paper presents a nation-wide spatially explicit object-based assessment of buildings and citizens exposed to natural hazards in Austria, including river flooding, torrential flooding, and snow avalanches. The assessment was based on two different datasets, (a) hazard information providing input to the exposure of elements at risk, and (b) information on the building stock combined from different spatial data available on the national level. Hazard information was compiled from two different sources. For torrential flooding and snow avalanches available local-scale hazard maps were used, and for river flooding the results of the countrywide flood modelling eHORA were available. Information on the building stock contained information on the location and size of each building, as well as on the building category and the construction period. Additional information related to the individual floors, such as their height and net area, main purpose and configuration, was included for each property. Moreover, this dataset has an interface to the population register and allowed therefore retrieving the number of primary residents for each building. With the exception of sacral buildings, an economic module was used to compute the monetary value of buildings using (a) the information of the building register such as building type, number of storeys and utilisation, and (b) regionally averaged construction costs. It is shown that the repeatedly-stated assumption of increasing exposure due to continued population growth and related increase in assets has to be carefully evaluated by the local development of building stock. While some regions have shown a clearly above-average increase in assets, other regions were characterised by a below-average development. This mirrors the topography of the country, but also the different economic activities. While hotels and hostels are extraordinary prone to torrential flooding, commercial buildings as well as buildings used for

Mapping flood and flooding potential indices: a methodological approach to identifying areas susceptible to flood and flooding risk. Case study: the Prahova catchment (Romania)

Science.gov (United States)

Zaharia, Liliana; Costache, Romulus; Prăvălie, Remus; Ioana-Toroimac, Gabriela

2017-04-01

Given that floods continue to cause yearly significant worldwide human and material damages, flood risk mitigation is a key issue and a permanent challenge in developing policies and strategies at various spatial scales. Therefore, a basic phase is elaborating hazard and flood risk maps, documents which are an essential support for flood risk management. The aim of this paper is to develop an approach that allows for the identification of flash-flood and flood-prone susceptible areas based on computing and mapping of two indices: FFPI (Flash-Flood Potential Index) and FPI (Flooding Potential Index). These indices are obtained by integrating in a GIS environment several geographical variables which control runoff (in the case of the FFPI) and favour flooding (in the case of the FPI). The methodology was applied in the upper (mountainous) and middle (hilly) catchment of the Prahova River, a densely populated and socioeconomically well-developed area which has been affected repeatedly by water-related hazards over the past decades. The resulting maps showing the spatialization of the FFPI and FPI allow for the identification of areas with high susceptibility to flashfloods and flooding. This approach can provide useful mapped information, especially for areas (generally large) where there are no flood/hazard risk maps. Moreover, the FFPI and FPI maps can constitute a preliminary step for flood risk and vulnerability assessment.

Using remotely sensed data and stochastic models to simulate realistic flood hazard footprints across the continental US

Science.gov (United States)

Bates, P. D.; Quinn, N.; Sampson, C. C.; Smith, A.; Wing, O.; Neal, J. C.

2017-12-01

Remotely sensed data has transformed the field of large scale hydraulic modelling. New digital elevation, hydrography and river width data has allowed such models to be created for the first time, and remotely sensed observations of water height, slope and water extent has allowed them to be calibrated and tested. As a result, we are now able to conduct flood risk analyses at national, continental or even global scales. However, continental scale analyses have significant additional complexity compared to typical flood risk modelling approaches. Traditional flood risk assessment uses frequency curves to define the magnitude of extreme flows at gauging stations. The flow values for given design events, such as the 1 in 100 year return period flow, are then used to drive hydraulic models in order to produce maps of flood hazard. Such an approach works well for single gauge locations and local models because over relatively short river reaches (say 10-60km) one can assume that the return period of an event does not vary. At regional to national scales and across multiple river catchments this assumption breaks down, and for a given flood event the return period will be different at different gauging stations, a pattern known as the event `footprint'. Despite this, many national scale risk analyses still use `constant in space' return period hazard layers (e.g. the FEMA Special Flood Hazard Areas) in their calculations. Such an approach can estimate potential exposure, but will over-estimate risk and cannot determine likely flood losses over a whole region or country. We address this problem by using a stochastic model to simulate many realistic extreme event footprints based on observed gauged flows and the statistics of gauge to gauge correlations. We take the entire USGS gauge data catalogue for sites with > 45 years of record and use a conditional approach for multivariate extreme values to generate sets of flood events with realistic return period variation in

44 CFR 65.5 - Revision to special hazard area boundaries with no change to base flood elevation determinations.

Science.gov (United States)

2010-10-01

... zones and floodways) it may be feasible to elevate areas with engineered earthen fill above the base... area boundaries with no change to base flood elevation determinations. 65.5 Section 65.5 Emergency... § 65.5 Revision to special hazard area boundaries with no change to base flood elevation determinations...

Hazard function analysis for flood planning under nonstationarity

Science.gov (United States)

Read, Laura K.; Vogel, Richard M.

2016-05-01

The field of hazard function analysis (HFA) involves a probabilistic assessment of the "time to failure" or "return period," T, of an event of interest. HFA is used in epidemiology, manufacturing, medicine, actuarial statistics, reliability engineering, economics, and elsewhere. For a stationary process, the probability distribution function (pdf) of the return period always follows an exponential distribution, the same is not true for nonstationary processes. When the process of interest, X, exhibits nonstationary behavior, HFA can provide a complementary approach to risk analysis with analytical tools particularly useful for hydrological applications. After a general introduction to HFA, we describe a new mathematical linkage between the magnitude of the flood event, X, and its return period, T, for nonstationary processes. We derive the probabilistic properties of T for a nonstationary one-parameter exponential model of X, and then use both Monte-Carlo simulation and HFA to generalize the behavior of T when X arises from a nonstationary two-parameter lognormal distribution. For this case, our findings suggest that a two-parameter Weibull distribution provides a reasonable approximation for the pdf of T. We document how HFA can provide an alternative approach to characterize the probabilistic properties of both nonstationary flood series and the resulting pdf of T.

The Generation of a Stochastic Flood Event Catalogue for Continental USA

Science.gov (United States)

Quinn, N.; Wing, O.; Smith, A.; Sampson, C. C.; Neal, J. C.; Bates, P. D.

2017-12-01

Recent advances in the acquisition of spatiotemporal environmental data and improvements in computational capabilities has enabled the generation of large scale, even global, flood hazard layers which serve as a critical decision-making tool for a range of end users. However, these datasets are designed to indicate only the probability and depth of inundation at a given location and are unable to describe the likelihood of concurrent flooding across multiple sites.Recent research has highlighted that although the estimation of large, widespread flood events is of great value to flood mitigation and insurance industries, to date it has been difficult to deal with this spatial dependence structure in flood risk over relatively large scales. Many existing approaches have been restricted to empirical estimates of risk based on historic events, limiting their capability of assessing risk over the full range of plausible scenarios. Therefore, this research utilises a recently developed model-based approach to describe the multisite joint distribution of extreme river flows across continental USA river gauges. Given an extreme event at a site, the model characterises the likelihood neighbouring sites are also impacted. This information is used to simulate an ensemble of plausible synthetic extreme event footprints from which flood depths are extracted from an existing global flood hazard catalogue. Expected economic losses are then estimated by overlaying flood depths with national datasets defining asset locations, characteristics and depth damage functions. The ability of this approach to quantify probabilistic economic risk and rare threshold exceeding events is expected to be of value to those interested in the flood mitigation and insurance sectors.This work describes the methodological steps taken to create the flood loss catalogue over a national scale; highlights the uncertainty in the expected annual economic vulnerability within the USA from extreme river flows

Mitigation of Flood Hazards Through Modification of Urban Channels and Floodplains

Science.gov (United States)

Miller, A. J.; Lee, G.; Bledsoe, B. P.; Stephens, T.

2017-12-01

Small urban watersheds with high percent impervious cover and dense road and storm-drain networks are highly responsive to short-duration high-intensity rainfall events that lead to flash floods. The Baltimore metropolitan area has some of the flashiest urban watersheds in the conterminous U.S., high frequency of channel incision in affected areas, and a large number of watershed restoration projects designed to restore ecosystem services through reconnection of the channel with the floodplain. A question of key importance in these and other urban watersheds is to what extent we can mitigate flood hazards and urban stream syndrome through restoration activities that modify the channel and valley floor. Local and state governments have invested resources in repairing damage caused by extreme events like the July 30, 2016 Ellicott City flood in the Tiber River watershed, as well as more frequent high flows in other local urban streams. Recent reports have investigated how much flood mitigation may be achieved through modification of the channel and floodplain to enhance short-term storage of flood waters on the valley floor or in other subsurface structures, as compared with increasing stormwater management in the headwaters. Ongoing research conducted as part of the UWIN (Urban Water Innovation Network) program utilizes high-resolution topographic point clouds derived by processing of photographs from hand-held cameras or video frames from drone overflights. These are used both to track geomorphic change and to assess flood response with 2d hydraulic modeling tools under alternative mitigation scenarios. Assessment metrics include variations in inundation extent, water depth, hydrograph attenuation, and temporal and spatial characteristics of the 2d depth-averaged velocity field. Examples from diverse urban watersheds are presented to illustrate the range of anticipated outcomes and potential constraints on the effectiveness of downstream vs. headwater mitigation

A methodology for the assessment of flood hazards at the regional scale

Science.gov (United States)

Gallina, Valentina; Torresan, Silvia; Critto, Andrea; Zabeo, Alex; Semenzin, Elena; Marcomini, Antonio

2013-04-01

In recent years, the frequency of water-related disasters has increased and recent flood events in Europe (e.g. 2002 in Central Europe, 2007 in UK, 2010 in Italy) caused physical-environmental and socio-economic damages. Specifically, floods are the most threatening water-related disaster that affects humans, their lives and properties. Within the KULTURisk project (FP7) a Regional Risk Assessment (RRA) methodology is proposed to evaluate the benefits of risk prevention in terms of reduced environmental risks due to floods. The method is based on the KULTURisk framework and allows the identification and prioritization of targets (i.e. people, buildings, infrastructures, agriculture, natural and semi-natural systems, cultural heritages) and areas at risk from floods in the considered region by comparing the baseline scenario (i.e. current state) with alternative scenarios (i.e. where different structural and/or non-structural measures are planned). The RRA methodology is flexible and can be adapted to different case studies (i.e. large rivers, alpine/mountain catchments, urban areas and coastal areas) and spatial scales (i.e. from the large river to the urban scale). The final aim of RRA is to help decision-makers in examining the possible environmental risks associated with uncertain future flood hazards and in identifying which prevention scenario could be the most suitable one. The RRA methodology employs Multi-Criteria Decision Analysis (MCDA functions) in order to integrate stakeholder preferences and experts judgments into the analysis. Moreover, Geographic Information Systems (GISs) are used to manage, process, analyze, and map data to facilitate the analysis and the information sharing with different experts and stakeholders. In order to characterize flood risks, the proposed methodology integrates the output of hydrodynamic models with the analysis of site-specific bio-geophysical and socio-economic indicators (e.g. slope of the territory, land cover

Protection of Basic Nuclear Installations Against External Flooding - Guide No. 13

International Nuclear Information System (INIS)

2013-01-01

in three parts: 1) Part II presents an approach for defining the reference flood situations (RFS) to consider in the flood hazard study, and then defines 11 RFSs; 2) Part III is devoted to the quantification of the parameters characterising the physical phenomena involved in the defined situations; 3) Part IV identifies the particularities of the flood hazard and the principles guiding the design choices and the means of protection to implement against the flood hazard

A Multi-Faceted Debris-Flood Hazard Assessment for Cougar Creek, Alberta, Canada

Directory of Open Access Journals (Sweden)

Matthias Jakob

2017-01-01

Full Text Available A destructive debris flood occurred between 19 and 21 June 2013 on Cougar Creek, located in Canmore, Alberta. Cougar Creek fan is likely the most densely developed alluvial fan in Canada. While no lives were lost, the event resulted in approximately $40 M of damage and closed both the Trans-Canada Highway (Highway 1 and the Canadian Pacific Railway line for a period of several days. The debris flood triggered a comprehensive hazard assessment which is the focus of this paper. Debris-flood frequencies and magnitudes are determined by combining several quantitative methods including photogrammetry, dendrochronology, radiometric dating, test pit logging, empirical relationships between rainfall volumes and sediment volumes, and landslide dam outburst flood modeling. The data analysis suggests that three distinct process types act in the watershed. The most frequent process is normal or “clearwater” floods. Less frequent but more damaging are debris floods during which excessive amounts of bedload are transported on the fan, typically associated with rapid and extensive bank erosion and channel infilling and widening. The third and most destructive process is interpreted to be landslide dam outbreak floods. This event type is estimated to occur at return periods exceeding 300 years. Using a cumulative magnitude frequency technique, the data for conventional debris floods were plotted up to the 100–300s year return period. A peak-over-threshold approach was used for landslide dam outbreak floods occurring at return periods exceeding 300 years, as not all such events were identified during test trenching. Hydrographs for 6 return period classes were approximated by using the estimated peak discharges and fitting the hydrograph shape to integrate to the debris flood volumes as determined from the frequency-magnitude relationship. The fan volume was calculated and compared with the integrated frequency-magnitude curve to check of the validity of

Flood Risk Management in the People’s Republic of China: Learning to Live with Flood Risk

OpenAIRE

Asian Development Bank (ADB); Asian Development Bank (ADB); Asian Development Bank (ADB); Asian Development Bank (ADB)

2012-01-01

This publication presents a shift in the People’s Republic of China from flood control depending on structural measures to integrated flood management using both structural and non-structural measures. The core of the new concept of integrated flood management is flood risk management. Flood risk management is based on an analysis of flood hazard, exposure to flood hazard, and vulnerability of people and property to danger. It is recommended that people learn to live with flood risks, gaining...

Capturing spatial and temporal patterns of widespread, extreme flooding across Europe

Science.gov (United States)

Busby, Kathryn; Raven, Emma; Liu, Ye

2013-04-01

Statistical characterisation of physical hazards is an integral part of probabilistic catastrophe models used by the reinsurance industry to estimate losses from large scale events. Extreme flood events are not restricted by country boundaries which poses an issue for reinsurance companies as their exposures often extend beyond them. We discuss challenges and solutions that allow us to appropriately capture the spatial and temporal dependence of extreme hydrological events on a continental-scale, which in turn enables us to generate an industry-standard stochastic event set for estimating financial losses for widespread flooding. By presenting our event set methodology, we focus on explaining how extreme value theory (EVT) and dependence modelling are used to account for short, inconsistent hydrological data from different countries, and how to make appropriate statistical decisions that best characterise the nature of flooding across Europe. The consistency of input data is of vital importance when identifying historical flood patterns. Collating data from numerous sources inherently causes inconsistencies and we demonstrate our robust approach to assessing the data and refining it to compile a single consistent dataset. This dataset is then extrapolated using a parameterised EVT distribution to estimate extremes. Our method then captures the dependence of flood events across countries using an advanced multivariate extreme value model. Throughout, important statistical decisions are explored including: (1) distribution choice; (2) the threshold to apply for extracting extreme data points; (3) a regional analysis; (4) the definition of a flood event, which is often linked with reinsurance industry's hour's clause; and (5) handling of missing values. Finally, having modelled the historical patterns of flooding across Europe, we sample from this model to generate our stochastic event set comprising of thousands of events over thousands of years. We then briefly

Multivariate pluvial flood damage models

International Nuclear Information System (INIS)

Van Ootegem, Luc; Verhofstadt, Elsy; Van Herck, Kristine; Creten, Tom

2015-01-01

Depth–damage-functions, relating the monetary flood damage to the depth of the inundation, are commonly used in the case of fluvial floods (floods caused by a river overflowing). We construct four multivariate damage models for pluvial floods (caused by extreme rainfall) by differentiating on the one hand between ground floor floods and basement floods and on the other hand between damage to residential buildings and damage to housing contents. We do not only take into account the effect of flood-depth on damage, but also incorporate the effects of non-hazard indicators (building characteristics, behavioural indicators and socio-economic variables). By using a Tobit-estimation technique on identified victims of pluvial floods in Flanders (Belgium), we take into account the effect of cases of reported zero damage. Our results show that the flood depth is an important predictor of damage, but with a diverging impact between ground floor floods and basement floods. Also non-hazard indicators are important. For example being aware of the risk just before the water enters the building reduces content damage considerably, underlining the importance of warning systems and policy in this case of pluvial floods. - Highlights: • Prediction of damage of pluvial floods using also non-hazard information • We include ‘no damage cases’ using a Tobit model. • The damage of flood depth is stronger for ground floor than for basement floods. • Non-hazard indicators are especially important for content damage. • Potential gain of policies that increase awareness of flood risks

Multivariate pluvial flood damage models

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Van Ootegem, Luc [HIVA — University of Louvain (Belgium); SHERPPA — Ghent University (Belgium); Verhofstadt, Elsy [SHERPPA — Ghent University (Belgium); Van Herck, Kristine; Creten, Tom [HIVA — University of Louvain (Belgium)

2015-09-15

Depth–damage-functions, relating the monetary flood damage to the depth of the inundation, are commonly used in the case of fluvial floods (floods caused by a river overflowing). We construct four multivariate damage models for pluvial floods (caused by extreme rainfall) by differentiating on the one hand between ground floor floods and basement floods and on the other hand between damage to residential buildings and damage to housing contents. We do not only take into account the effect of flood-depth on damage, but also incorporate the effects of non-hazard indicators (building characteristics, behavioural indicators and socio-economic variables). By using a Tobit-estimation technique on identified victims of pluvial floods in Flanders (Belgium), we take into account the effect of cases of reported zero damage. Our results show that the flood depth is an important predictor of damage, but with a diverging impact between ground floor floods and basement floods. Also non-hazard indicators are important. For example being aware of the risk just before the water enters the building reduces content damage considerably, underlining the importance of warning systems and policy in this case of pluvial floods. - Highlights: • Prediction of damage of pluvial floods using also non-hazard information • We include ‘no damage cases’ using a Tobit model. • The damage of flood depth is stronger for ground floor than for basement floods. • Non-hazard indicators are especially important for content damage. • Potential gain of policies that increase awareness of flood risks.

Spatiotemporal hazard mapping of a flood event "migration" in a transboundary river basin as an operational tool in flood risk management

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Perrou, Theodora; Papastergios, Asterios; Parcharidis, Issaak; Chini, Marco

2017-10-01

Flood disaster is one of the heaviest disasters in the world. It is necessary to monitor and evaluate the flood disaster in order to mitigate the consequences. As floods do not recognize borders, transboundary flood risk management is imperative in shared river basins. Disaster management is highly dependent on early information and requires data from the whole river basin. Based on the hypothesis that the flood events over the same area with same magnitude have almost identical evolution, it is crucial to develop a repository database of historical flood events. This tool, in the case of extended transboundary river basins, could constitute an operational warning system for the downstream area. The utility of SAR images for flood mapping, was demonstrated by previous studies but the SAR systems in orbit were not characterized by high operational capacity. Copernicus system will fill this gap in operational service for risk management, especially during emergency phase. The operational capabilities have been significantly improved by newly available satellite constellation, such as the Sentinel-1A AB mission, which is able to provide systematic acquisitions with a very high temporal resolution in a wide swath coverage. The present study deals with the monitoring of a transboundary flood event in Evros basin. The objective of the study is to create the "migration story" of the flooded areas on the basis of the evolution in time for the event occurred from October 2014 till May 2015. Flood hazard maps will be created, using SAR-based semi-automatic algorithms and then through the synthesis of the related maps in a GIS-system, a spatiotemporal thematic map of the event will be produced. The thematic map combined with TanDEM-X DEM, 12m/pixel spatial resolution, will define the non- affected areas which is a very useful information for the emergency planning and emergency response phases. The Sentinels meet the main requirements to be an effective and suitable

Flood-hazard analysis of four headwater streams draining the Argonne National Laboratory property, DuPage County, Illinois

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Soong, David T.; Murphy, Elizabeth A.; Straub, Timothy D.; Zeeb, Hannah L.

2016-11-22

Results of a flood-hazard analysis conducted by the U.S. Geological Survey, in cooperation with the Argonne National Laboratory, for four headwater streams within the Argonne National Laboratory property indicate that the 1-percent and 0.2-percent annual exceedance probability floods would cause multiple roads to be overtopped. Results indicate that most of the effects on the infrastructure would be from flooding of Freund Brook. Flooding on the Northeast and Southeast Drainage Ways would be limited to overtopping of one road crossing for each of those streams. The Northwest Drainage Way would be the least affected with flooding expected to occur in open grass or forested areas.The Argonne Site Sustainability Plan outlined the development of hydrologic and hydraulic models and the creation of flood-plain maps of the existing site conditions as a first step in addressing resiliency to possible climate change impacts as required by Executive Order 13653 “Preparing the United States for the Impacts of Climate Change.” The Hydrological Simulation Program-FORTRAN is the hydrologic model used in the study, and the Hydrologic Engineering Center‒River Analysis System (HEC–RAS) is the hydraulic model. The model results were verified by comparing simulated water-surface elevations to observed water-surface elevations measured at a network of five crest-stage gages on the four study streams. The comparison between crest-stage gage and simulated elevations resulted in an average absolute difference of 0.06 feet and a maximum difference of 0.19 feet.In addition to the flood-hazard model development and mapping, a qualitative stream assessment was conducted to evaluate stream channel and substrate conditions in the study reaches. This information can be used to evaluate erosion potential.

A combined morphometric, sedimentary, GIS and modelling analysis of flooding and debris flow hazard on a composite alluvial fan, Caveside, Tasmania

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Kain, Claire L.; Rigby, Edward H.; Mazengarb, Colin

2018-02-01

Two episodes of intense flooding and sediment movement occurred in the Westmorland Stream alluvial system near Caveside, Australia in January 2011 and June 2016. The events were investigated in order to better understand the drivers and functioning of this composite alluvial system on a larger scale, so as to provide awareness of the potential hazard from future flood and debris flow events. A novel combination of methods was employed, including field surveys, catchment morphometry, GIS mapping from LiDAR and aerial imagery, and hydraulic modelling using RiverFlow-2D software. Both events were initiated by extreme rainfall events (events on the farmland appeared similar; however, there were differences in sediment source and transport processes that have implications for understanding recurrence probabilities. A debris flow was a key driver in the 2011 event, by eroding the stream channel in the forested watershed and delivering a large volume of sediment downstream to the alluvial fan. In contrast, modelled flooding velocities suggest the impacts of the 2016 event were the result of an extended period of extreme stream flooding and consequent erosion of alluvium directly above the current fan apex. The morphometry of the catchment is better aligned with values from fluvially dominated fans found elsewhere, which suggests that flooding represents a more frequent future risk than debris flows. These findings have wider implications for the estimation of debris flow and flood hazard on alluvial fans in Tasmania and elsewhere, as well as further demonstrating the capacity of combined hydraulic modelling and geomorphologic investigation as a predictive tool to inform hazard management practices in environments affected by flooding and sediment movement.

FLOOD HAZARDS PERCEPTION. THE RESULT OF AN OPINION SURVEY MADE IN THE LITTLE TOWNS FROM LOWER ARIEŞ CORRIDOR

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IOANA URCAN

2012-12-01

Full Text Available Flood hazards perception. The result of an opinion survey made in the little towns from lower Arieş corridor. This paper has been prepared based on information obtained from a survey conducted on a sample of 560 residents from the towns of Turda and Câmpia Turzii, residing in areas with different degrees of exposure to the risk of flooding. The residents were questioned about the floods they had suffered and gave varied responses to the degree of flood damage on the population, to the amount of information and the degree of insurance against floods. The questionnaire was structured on different aspects that emphasized: identification, level of experience, knowledge and information; the perception of the causes that generated and amplified floods; the perception involving authorities in prevention and mitigation of flood damage; availability for implementation of voluntary actions, the degree of insurance and aid to flood. In this study it was taken into account the location of households, the previous flood experience, the age and the education level of the respondents.

Public perception of flood risks, flood forecasting and mitigation

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M. Brilly

2005-01-01

Full Text Available A multidisciplinary and integrated approach to the flood mitigation decision making process should provide the best response of society in a flood hazard situation including preparation works and post hazard mitigation. In Slovenia, there is a great lack of data on social aspects and public response to flood mitigation measures and information management. In this paper, two studies of flood perception in the Slovenian town Celje are represented. During its history, Celje was often exposed to floods, the most recent serious floods being in 1990 and in 1998, with a hundred and fifty return period and more than ten year return period, respectively. Two surveys were conducted in 1997 and 2003, with 157 participants from different areas of the town in the first, and 208 in the second study, aiming at finding the general attitude toward the floods. The surveys revealed that floods present a serious threat in the eyes of the inhabitants, and that the perception of threat depends, to a certain degree, on the place of residence. The surveys also highlighted, among the other measures, solidarity and the importance of insurance against floods.

High resolution global flood hazard map from physically-based hydrologic and hydraulic models.

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Begnudelli, L.; Kaheil, Y.; McCollum, J.

2017-12-01

The global flood map published online at http://www.fmglobal.com/research-and-resources/global-flood-map at 90m resolution is being used worldwide to understand flood risk exposure, exercise certain measures of mitigation, and/or transfer the residual risk financially through flood insurance programs. The modeling system is based on a physically-based hydrologic model to simulate river discharges, and 2D shallow-water hydrodynamic model to simulate inundation. The model can be applied to large-scale flood hazard mapping thanks to several solutions that maximize its efficiency and the use of parallel computing. The hydrologic component of the modeling system is the Hillslope River Routing (HRR) hydrologic model. HRR simulates hydrological processes using a Green-Ampt parameterization, and is calibrated against observed discharge data from several publicly-available datasets. For inundation mapping, we use a 2D Finite-Volume Shallow-Water model with wetting/drying. We introduce here a grid Up-Scaling Technique (UST) for hydraulic modeling to perform simulations at higher resolution at global scale with relatively short computational times. A 30m SRTM is now available worldwide along with higher accuracy and/or resolution local Digital Elevation Models (DEMs) in many countries and regions. UST consists of aggregating computational cells, thus forming a coarser grid, while retaining the topographic information from the original full-resolution mesh. The full-resolution topography is used for building relationships between volume and free surface elevation inside cells and computing inter-cell fluxes. This approach almost achieves computational speed typical of the coarse grids while preserving, to a significant extent, the accuracy offered by the much higher resolution available DEM. The simulations are carried out along each river of the network by forcing the hydraulic model with the streamflow hydrographs generated by HRR. Hydrographs are scaled so that the peak

Combining criteria for delineating lahar- and flash-flood-prone hazard and risk zones for the city of Arequipa, Peru

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Thouret, J.-C.; Enjolras, G.; Martelli, K.; Santoni, O.; Luque, J. A.; Nagata, M.; Arguedas, A.; Macedo, L.

2013-02-01

Arequipa, the second largest city in Peru, is exposed to many natural hazards, most notably earthquakes, volcanic eruptions, landslides, lahars (volcanic debris flows), and flash floods. Of these, lahars and flash floods, triggered by occasional torrential rainfall, pose the most frequently occurring hazards that can affect the city and its environs, in particular the areas containing low-income neighbourhoods. This paper presents and discusses criteria for delineating areas prone to flash flood and lahar hazards, which are localized along the usually dry (except for the rainy season) ravines and channels of the Río Chili and its tributaries that dissect the city. Our risk-evaluation study is based mostly on field surveys and mapping, but we also took into account quality and structural integrity of buildings, available socio-economic data, and information gained from interviews with risk-managers officials. In our evaluation of the vulnerability of various parts of the city, in addition to geological and physical parameters, we also took into account selected socio-economic parameters, such as the educational and poverty level of the population, unemployment figures, and population density. In addition, we utilized a criterion of the "isolation factor", based on distances to access emergency resources (hospitals, shelters or safety areas, and water) in each city block. By combining the hazard, vulnerability and exposure criteria, we produced detailed risk-zone maps at the city-block scale, covering the whole city of Arequipa and adjacent suburbs. Not surprisingly, these maps show that the areas at high risk coincide with blocks or districts with populations at low socio-economic levels. Inhabitants at greatest risk are the poor recent immigrants from rural areas who live in unauthorized settlements in the outskirts of the city in the upper parts of the valleys. Such settlements are highly exposed to natural hazards and have little access to vital resources. Our

Flash flood hazard assessment through modelling in small semi-arid watersheds. The example of the Beni Mellal watershed in Morocco

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Werren, G.; Balin, D.; Reynard, E.; Lane, S. N.

2012-04-01

Flood modelling is essential for flood hazard assessment. Modelling becomes a challenge in small, ungauged watersheds prone to flash floods, like the ones draining the town of Beni Mellal (Morocco). Four temporary streams meet in the urban area of Beni Mellal, producing every year sheet floods, harmful to infrastructure and to people. Here, statistical analysis may not give realistic results, but the study of these repeated real flash flood events may provide a better understanding of watershed specific hydrology. This study integrates a larger cooperation project between Switzerland and Morroco, aimed at knowledge transfer in disaster risk reduction, especially through hazard mapping and land-use planning, related to implementation of hazard maps. Hydrologic and hydraulic modelling was carried out to obtain hazard maps. An important point was to find open source data and methods that could still produce a realistic model for the area concerned, in order to provide easy-to-use, cost-effective tools for risk management in developing countries like Morocco, where routine data collection is largely lacking. The data used for modelling is the Web available TRMM 3-Hour 0.25 degree rainfall data provided by the Tropical Rainfall Measurement Mission Project (TRMM). Hydrologic modelling for discharge estimation was undertaken using methods available in the HEC-HMS software provided by the US Army Corps of Engineers® (USACE). Several transfer models were used, so as to choose the best-suited method available. As no model calibration was possible for no measured flow data was available, a one-at-the-time sensitivity analysis was performed on the parameters chosen, in order to detect their influence on the results. But the most important verification method remained field observation, through post-flood field campaigns aimed at mapping water surfaces and depths in the flooded areas, as well as river section monitoring, where rough discharge estimates could be obtained using

Flood damage data gathering: procedures and use

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Molinari, D.; Aronica, G. T.; Ballio, F.; Berni, N.; Pandolfo, C.

2012-04-01

Damage data represents the basis on which flood risk models, re-founding schemes and mitigation activities are grounded on. Nevertheless damage data have been collected so far mainly at the national-regional scale; few databases exist at the local scale and, even if present, no standard exist for their development. On the contrary, risk analyses and mitigation strategies are usually carried out at local scale. This contribution describes the ongoing activity to collect and analyze local damage data coming from past events with recently hit Umbria an Sicily regions (central and south part of Italy respectively). Data from past events will be discussed from two different perspectives. In Italy, procedures to gather damage data after a flood are defined by law. According to this, authors will first question whether or not collected data are suitable to give an exhaustive representation of the total impact the events had on the affected territories. As regards, suggestions are provided about how gathering procedures can improve. On the other hand, collected data will be discussed with respect to their implementation in the definition of depth-damage curves for the Italian context; literature review highlights indeed that no curves are available for Italy. Starting from the knowledge of observed hazard intensity and damage data, available curves from other countries are validated, the objective being to reduce the uncertainty which currently characterise damage estimation. Indeed, a variety of curves can be found in literature and the choice of one curve in place of another can change damage assessment results of one order of magnitude. The validation procedure will allow, in its turn, to face a secondary but key question for the contribution, being the identification of those hazard and vulnerability features that should be recorded and kept updated in a local GIS database to support risk modelling, funding and management. The two areas under investigation are prone to

Cities and Sea Level Rise: A Roadmap for Flood Hazard Adaptation

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Horn, Diane; Cousins, Ann

2016-04-01

defend all areas nor retreat entirely and will need to make a decision to retreat from certain locations or to relocate particular assets in areas at lower risk. We identify a series of specific questions which should be answered by city managers when selecting the most appropriate response for a particular location. The selection of options appropriate for building resilience does not depend entirely on the nature of the physical hazard and the accommodation space available, but also on the socio-political and environmental context in which adaptation decisions are made. The most important element in adapting to sea level rise is to have policies in place that incentivise risk reduction. The more comprehensively adaptation measures can be integrated into related policy areas and linked up with existing economic, social and environment measures, the more successful adaptation policies are likely to be. Changes to planning regulations, although resource-intensive, are the most cost-effective way of managing risk exposure over time. Flood insurance can also serve as a highly persuasive financial incentive for flood-resilient construction and locating businesses and homes in safer locations.

Flash flood characterisation of the Haor area of Bangladesh

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Bhattacharya, B.; Suman, A.

2012-04-01

Haors are large bowl-shaped flood plain depressions located mostly in north-eastern part of Bangladesh covering about 25% of the entire region. During dry season haors are used for agriculture and during rainy season it is used as fisheries. Haors have profound ecological importance. About 8000 migratory wild birds visit the area annually. Some of the haors are declared at Ramsar sites. Haors are frequently affected by the flash floods due to hilly topography and steep slope of the rivers draining the area. These flash floods spill onto low-lying flood plain lands in the region, inundating crops, damaging infrastructure by erosion and often causing loss of lives and properties. Climate change is exacerbating the situation. For appropriate risk mitigation mechanism it is necessary to explore flood characteristics of that region. The area is not at all studied well. Under a current project a numerical 1D2D model based on MIKE Flood is developed to study the flooding characteristics and estimate the climate change impacts on the haor region. Under this study the progression of flood levels at some key haors in relation to the water level data at specified gauges in the region is analysed. As the region is at the border with India so comparing with the gauges at the border with India is carried out. The flooding in the Haor area is associated with the rainfall in the upstream catchment in India (Meghalaya, Barak and Tripura basins in India). The flood propagation in some of the identified haors in relation to meteorological forcing in the three basins in India is analysed as well. Subsequently, a ranking of haors is done based on individual risks. Based on the IPCC recommendation the precipitation scenario in the upstream catchments under climate change is considered. The study provides the fundamental inputs for preparing a flood risk management plan of the region.

HERA: A dynamic web application for visualizing community exposure to flood hazards based on storm and sea level rise scenarios

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Jones, Jeanne M.; Henry, Kevin; Wood, Nathan J.; Ng, Peter; Jamieson, Matthew

2017-01-01

The Hazard Exposure Reporting and Analytics (HERA) dynamic web application was created to provide a platform that makes research on community exposure to coastal-flooding hazards influenced by sea level rise accessible to planners, decision makers, and the public in a manner that is both easy to use and easily accessible. HERA allows users to (a) choose flood-hazard scenarios based on sea level rise and storm assumptions, (b) appreciate the modeling uncertainty behind a chosen hazard zone, (c) select one or several communities to examine exposure, (d) select the category of population or societal asset, and (e) choose how to look at results. The application is designed to highlight comparisons between (a) varying levels of sea level rise and coastal storms, (b) communities, (c) societal asset categories, and (d) spatial scales. Through a combination of spatial and graphical visualizations, HERA aims to help individuals and organizations to craft more informed mitigation and adaptation strategies for climate-driven coastal hazards. This paper summarizes the technologies used to maximize the user experience, in terms of interface design, visualization approaches, and data processing.

HERA: A dynamic web application for visualizing community exposure to flood hazards based on storm and sea level rise scenarios

Science.gov (United States)

Jones, Jeanne M.; Henry, Kevin; Wood, Nathan; Ng, Peter; Jamieson, Matthew

2017-12-01

The Hazard Exposure Reporting and Analytics (HERA) dynamic web application was created to provide a platform that makes research on community exposure to coastal-flooding hazards influenced by sea level rise accessible to planners, decision makers, and the public in a manner that is both easy to use and easily accessible. HERA allows users to (a) choose flood-hazard scenarios based on sea level rise and storm assumptions, (b) appreciate the modeling uncertainty behind a chosen hazard zone, (c) select one or several communities to examine exposure, (d) select the category of population or societal asset, and (e) choose how to look at results. The application is designed to highlight comparisons between (a) varying levels of sea level rise and coastal storms, (b) communities, (c) societal asset categories, and (d) spatial scales. Through a combination of spatial and graphical visualizations, HERA aims to help individuals and organizations to craft more informed mitigation and adaptation strategies for climate-driven coastal hazards. This paper summarizes the technologies used to maximize the user experience, in terms of interface design, visualization approaches, and data processing.

A metric-based assessment of flood risk and vulnerability of rural communities in the Lower Shire Valley, Malawi

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Adeloye, A. J.; Mwale, F. D.; Dulanya, Z.

2015-06-01

In response to the increasing frequency and economic damages of natural disasters globally, disaster risk management has evolved to incorporate risk assessments that are multi-dimensional, integrated and metric-based. This is to support knowledge-based decision making and hence sustainable risk reduction. In Malawi and most of Sub-Saharan Africa (SSA), however, flood risk studies remain focussed on understanding causation, impacts, perceptions and coping and adaptation measures. Using the IPCC Framework, this study has quantified and profiled risk to flooding of rural, subsistent communities in the Lower Shire Valley, Malawi. Flood risk was obtained by integrating hazard and vulnerability. Flood hazard was characterised in terms of flood depth and inundation area obtained through hydraulic modelling in the valley with Lisflood-FP, while the vulnerability was indexed through analysis of exposure, susceptibility and capacity that were linked to social, economic, environmental and physical perspectives. Data on these were collected through structured interviews of the communities. The implementation of the entire analysis within GIS enabled the visualisation of spatial variability in flood risk in the valley. The results show predominantly medium levels in hazardousness, vulnerability and risk. The vulnerability is dominated by a high to very high susceptibility. Economic and physical capacities tend to be predominantly low but social capacity is significantly high, resulting in overall medium levels of capacity-induced vulnerability. Exposure manifests as medium. The vulnerability and risk showed marginal spatial variability. The paper concludes with recommendations on how these outcomes could inform policy interventions in the Valley.

Multi-temporal clustering of continental floods and associated atmospheric circulations

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Liu, Jianyu; Zhang, Yongqiang

2017-12-01

Investigating clustering of floods has important social, economic and ecological implications. This study examines the clustering of Australian floods at different temporal scales and its possible physical mechanisms. Flood series with different severities are obtained by peaks-over-threshold (POT) sampling in four flood thresholds. At intra-annual scale, Cox regression and monthly frequency methods are used to examine whether and when the flood clustering exists, respectively. At inter-annual scale, dispersion indices with four-time variation windows are applied to investigate the inter-annual flood clustering and its variation. Furthermore, the Kernel occurrence rate estimate and bootstrap resampling methods are used to identify flood-rich/flood-poor periods. Finally, seasonal variation of horizontal wind at 850 hPa and vertical wind velocity at 500 hPa are used to investigate the possible mechanisms causing the temporal flood clustering. Our results show that: (1) flood occurrences exhibit clustering at intra-annual scale, which are regulated by climate indices representing the impacts of the Pacific and Indian Oceans; (2) the flood-rich months occur from January to March over northern Australia, and from July to September over southwestern and southeastern Australia; (3) stronger inter-annual clustering takes place across southern Australia than northern Australia; and (4) Australian floods are characterised by regional flood-rich and flood-poor periods, with 1987-1992 identified as the flood-rich period across southern Australia, but the flood-poor period across northern Australia, and 2001-2006 being the flood-poor period across most regions of Australia. The intra-annual and inter-annual clustering and temporal variation of flood occurrences are in accordance with the variation of atmospheric circulation. These results provide relevant information for flood management under the influence of climate variability, and, therefore, are helpful for developing

Tsunami hazard assessment in El Salvador, Central America, from seismic sources through flooding numerical models.

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Álvarez-Gómez, J. A.; Aniel-Quiroga, Í.; Gutiérrez-Gutiérrez, O. Q.; Larreynaga, J.; González, M.; Castro, M.; Gavidia, F.; Aguirre-Ayerbe, I.; González-Riancho, P.; Carreño, E.

2013-11-01

El Salvador is the smallest and most densely populated country in Central America; its coast has an approximate length of 320 km, 29 municipalities and more than 700 000 inhabitants. In El Salvador there were 15 recorded tsunamis between 1859 and 2012, 3 of them causing damages and resulting in hundreds of victims. Hazard assessment is commonly based on propagation numerical models for earthquake-generated tsunamis and can be approached through both probabilistic and deterministic methods. A deterministic approximation has been applied in this study as it provides essential information for coastal planning and management. The objective of the research was twofold: on the one hand the characterization of the threat over the entire coast of El Salvador, and on the other the computation of flooding maps for the three main localities of the Salvadorian coast. For the latter we developed high-resolution flooding models. For the former, due to the extension of the coastal area, we computed maximum elevation maps, and from the elevation in the near shore we computed an estimation of the run-up and the flooded area using empirical relations. We have considered local sources located in the Middle America Trench, characterized seismotectonically, and distant sources in the rest of Pacific Basin, using historical and recent earthquakes and tsunamis. We used a hybrid finite differences-finite volumes numerical model in this work, based on the linear and non-linear shallow water equations, to simulate a total of 24 earthquake-generated tsunami scenarios. Our results show that at the western Salvadorian coast, run-up values higher than 5 m are common, while in the eastern area, approximately from La Libertad to the Gulf of Fonseca, the run-up values are lower. The more exposed areas to flooding are the lowlands in the Lempa River delta and the Barra de Santiago Western Plains. The results of the empirical approximation used for the whole country are similar to the results

Assessing coastal flooding hazard in urban areas: the case of estuarian villages in the city of Hyères-les-Palmiers

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Le Roy Sylvestre

2016-01-01

Full Text Available This study, conducted on the city of Hyéres-les-Palmiers (French Riviera to guide the future land use planning, aimed to evaluate how sea level rise could modify coastal flooding hazards in urban areas located near small estuaries in a microtidal context. A joint probability approach allowed establishing typical storm parameters for specific return periods (30, 50 and 100 years, integrating offshore conditions (sea level and significant wave height and the river level. Storm scenarios have been established from these parameters and the chronology of the most impacting recent storm. Sea level rise has been integrated (20 cm for year 2030 and 60 cm for year 2100, and the coastal flooding has been simulated with a non-hydrostatic non-linear shallow-water model (SWASH. The calculations have been realized on high resolution DEM (1 to 5 m mesh size, integrating buildings and coastal protections. The approach has been validated by reproducing a recent flooding event. Obtained results show the importance of wave overtopping in current coastal flooding hazard in this area. Nevertheless, if Hyéres-les-Palmiers is currently little exposed to coastal flooding, these simulations highlight an increasing role of overflowing due to sea level rise, leading to significant flooding in 2100, even for quite frequent events.

Impact of climate change on New York City's coastal flood hazard: Increasing flood heights from the preindustrial to 2300 CE.

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Garner, Andra J; Mann, Michael E; Emanuel, Kerry A; Kopp, Robert E; Lin, Ning; Alley, Richard B; Horton, Benjamin P; DeConto, Robert M; Donnelly, Jeffrey P; Pollard, David

2017-11-07

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the preindustrial era through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP8.5 simulations from three CMIP5 models. The sea-level rise projections account for potential partial collapse of the Antarctic ice sheet in assessing future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared with preindustrial or modern flood heights. For the various sea-level rise scenarios we consider, the 1-in-500-y flood event increases from 3.4 m above mean tidal level during 1970-2005 to 4.0-5.1 m above mean tidal level by 2080-2100 and ranges from 5.0-15.4 m above mean tidal level by 2280-2300. Further, we find that the return period of a 2.25-m flood has decreased from ∼500 y before 1800 to ∼25 y during 1970-2005 and further decreases to ∼5 y by 2030-2045 in 95% of our simulations. The 2.25-m flood height is permanently exceeded by 2280-2300 for scenarios that include Antarctica's potential partial collapse. Copyright © 2017 the Author(s). Published by PNAS.

Enhancing flood hazard estimation methods on alluvial fans using an integrated hydraulic, geological and geomorphological approach

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Mollaei, Zeinab; Davary, Kamran; Majid Hasheminia, Seyed; Faridhosseini, Alireza; Pourmohamad, Yavar

2018-04-01

Due to the uncertainty concerning the location of flow paths on active alluvial fans, alluvial fan floods could be more dangerous than riverine floods. The United States Federal Emergency Management Agency (FEMA) used a simple stochastic model named FAN for this purpose, which has been practiced for many years. In the last decade, this model has been criticized as a consequence of development of more complex computer models. This study was conducted on three alluvial fans located in northeast and southeast Iran using a combination of the FAN model, the hydraulic portion of the FLO-2D model, and geomorphological information. Initial stages included three steps: (a) identifying the alluvial fans' landforms, (b) determining the active and inactive areas of alluvial fans, and (c) delineating 100-year flood within these selected areas. This information was used as an input in the mentioned three approaches of the (i) FLO-2D model, (ii) geomorphological method, and (iii) FAN model. Thereafter, the results of each model were obtained and geographical information system (GIS) layers were created and overlaid. Afterwards, using a scoring system, the results were evaluated and compared. The goal of this research was to introduce a simple but effective solution to estimate the flood hazards. It was concluded that the integrated method proposed in this study is superior at projecting alluvial fan flood hazards with minimum required input data, simplicity, and affordability, which are considered the primary goals of such comprehensive studies. These advantages are more highlighted in underdeveloped and developing countries, which may well lack detailed data and financially cannot support such costly projects. Furthermore, such a highly cost-effective method could be greatly advantageous and pragmatic for developed countries.

Development of Probabilistic Flood Inundation Mapping For Flooding Induced by Dam Failure

Science.gov (United States)

Tsai, C.; Yeh, J. J. J.

2017-12-01

A primary function of flood inundation mapping is to forecast flood hazards and assess potential losses. However, uncertainties limit the reliability of inundation hazard assessments. Major sources of uncertainty should be taken into consideration by an optimal flood management strategy. This study focuses on the 20km reach downstream of the Shihmen Reservoir in Taiwan. A dam failure induced flood herein provides the upstream boundary conditions of flood routing. The two major sources of uncertainty that are considered in the hydraulic model and the flood inundation mapping herein are uncertainties in the dam break model and uncertainty of the roughness coefficient. The perturbance moment method is applied to a dam break model and the hydro system model to develop probabilistic flood inundation mapping. Various numbers of uncertain variables can be considered in these models and the variability of outputs can be quantified. The probabilistic flood inundation mapping for dam break induced floods can be developed with consideration of the variability of output using a commonly used HEC-RAS model. Different probabilistic flood inundation mappings are discussed and compared. Probabilistic flood inundation mappings are hoped to provide new physical insights in support of the evaluation of concerning reservoir flooded areas.

Combining criteria for delineating lahar- and flash-flood-prone hazard and risk zones for the city of Arequipa, Peru

Directory of Open Access Journals (Sweden)

J.-C. Thouret

2013-02-01

Full Text Available Arequipa, the second largest city in Peru, is exposed to many natural hazards, most notably earthquakes, volcanic eruptions, landslides, lahars (volcanic debris flows, and flash floods. Of these, lahars and flash floods, triggered by occasional torrential rainfall, pose the most frequently occurring hazards that can affect the city and its environs, in particular the areas containing low-income neighbourhoods. This paper presents and discusses criteria for delineating areas prone to flash flood and lahar hazards, which are localized along the usually dry (except for the rainy season ravines and channels of the Río Chili and its tributaries that dissect the city. Our risk-evaluation study is based mostly on field surveys and mapping, but we also took into account quality and structural integrity of buildings, available socio-economic data, and information gained from interviews with risk-managers officials.

In our evaluation of the vulnerability of various parts of the city, in addition to geological and physical parameters, we also took into account selected socio-economic parameters, such as the educational and poverty level of the population, unemployment figures, and population density. In addition, we utilized a criterion of the "isolation factor", based on distances to access emergency resources (hospitals, shelters or safety areas, and water in each city block. By combining the hazard, vulnerability and exposure criteria, we produced detailed risk-zone maps at the city-block scale, covering the whole city of Arequipa and adjacent suburbs. Not surprisingly, these maps show that the areas at high risk coincide with blocks or districts with populations at low socio-economic levels. Inhabitants at greatest risk are the poor recent immigrants from rural areas who live in unauthorized settlements in the outskirts of the city in the upper parts of the valleys. Such settlements are highly exposed to natural hazards and have little access

Drivers of flood damage on event level

DEFF Research Database (Denmark)

Kreibich, H.; Aerts, J. C. J. H.; Apel, H.

2016-01-01

Flood risk is dynamic and influenced by many processes related to hazard, exposure and vulnerability. Flood damage increased significantly over the past decades, however, resulting overall economic loss per event is an aggregated indicator and it is difficult to attribute causes to this increasing...... trend. Much has been learned about damaging processes during floods at the micro-scale, e.g. building level. However, little is known about the main factors determining the amount of flood damage on event level. Thus, we analyse and compare paired flood events, i.e. consecutive, similar damaging floods...... example are the 2002 and 2013 floods in the Elbe and Danube catchments in Germany. The 2002 flood caused the highest economic damage (EUR 11600 million) due to a natural hazard event in Germany. Damage was so high due to extreme flood hazard triggered by extreme precipitation and a high number...

Current and future pluvial flood hazard analysis for the city of Antwerp

Science.gov (United States)

Willems, Patrick; Tabari, Hossein; De Niel, Jan; Van Uytven, Els; Lambrechts, Griet; Wellens, Geert

2016-04-01

to two types of methods). These were finally transferred into future pluvial flash flood hazard maps for the city together with the uncertainties, and are considered as basis for spatial planning and adaptation.

HANZE: a pan-European database of exposure to natural hazards and damaging historical floods since 1870

Science.gov (United States)

Paprotny, Dominik; Morales-Nápoles, Oswaldo; Jonkman, Sebastiaan N.

2018-03-01

The influence of social and economic change on the consequences of natural hazards has been a matter of much interest recently. However, there is a lack of comprehensive, high-resolution data on historical changes in land use, population, or assets available to study this topic. Here, we present the Historical Analysis of Natural Hazards in Europe (HANZE) database, which contains two parts: (1) HANZE-Exposure with maps for 37 countries and territories from 1870 to 2020 in 100 m resolution and (2) HANZE-Events, a compilation of past disasters with information on dates, locations, and losses, currently limited to floods only. The database was constructed using high-resolution maps of present land use and population, a large compilation of historical statistics, and relatively simple disaggregation techniques and rule-based land use reallocation schemes. Data encompassed in HANZE allow one to "normalize" information on losses due to natural hazards by taking into account inflation as well as changes in population, production, and wealth. This database of past events currently contains 1564 records (1870-2016) of flash, river, coastal, and compound floods. The HANZE database is freely available at https://data.4tu.nl/repository/collection:HANZE" target="_blank">https://data.4tu.nl/repository/collection:HANZE.

Accumulation risk assessment for the flooding hazard

Science.gov (United States)

Roth, Giorgio; Ghizzoni, Tatiana; Rudari, Roberto

2010-05-01

One of the main consequences of the demographic and economic development and of markets and trades globalization is represented by risks cumulus. In most cases, the cumulus of risks intuitively arises from the geographic concentration of a number of vulnerable elements in a single place. For natural events, risks cumulus can be associated, in addition to intensity, also to event's extension. In this case, the magnitude can be such that large areas, that may include many regions or even large portions of different countries, are stroked by single, catastrophic, events. Among natural risks, the impact of the flooding hazard cannot be understated. To cope with, a variety of mitigation actions can be put in place: from the improvement of monitoring and alert systems to the development of hydraulic structures, throughout land use restrictions, civil protection, financial and insurance plans. All of those viable options present social and economic impacts, either positive or negative, whose proper estimate should rely on the assumption of appropriate - present and future - flood risk scenarios. It is therefore necessary to identify proper statistical methodologies, able to describe the multivariate aspects of the involved physical processes and their spatial dependence. In hydrology and meteorology, but also in finance and insurance practice, it has early been recognized that classical statistical theory distributions (e.g., the normal and gamma families) are of restricted use for modeling multivariate spatial data. Recent research efforts have been therefore directed towards developing statistical models capable of describing the forms of asymmetry manifest in data sets. This, in particular, for the quite frequent case of phenomena whose empirical outcome behaves in a non-normal fashion, but still maintains some broad similarity with the multivariate normal distribution. Fruitful approaches were recognized in the use of flexible models, which include the normal

Flooding and Flood Management

Science.gov (United States)

Brooks, K.N.; Fallon, J.D.; Lorenz, D.L.; Stark, J.R.; Menard, Jason; Easter, K.W.; Perry, Jim

2011-01-01

Floods result in great human disasters globally and nationally, causing an average of $4 billion of damages each year in the United States. Minnesota has its share of floods and flood damages, and the state has awarded nearly $278 million to local units of government for flood mitigation projects through its Flood Hazard Mitigation Grant Program. Since 1995, flood mitigation in the Red River Valley has exceeded $146 million. Considerable local and state funding has been provided to manage and mitigate problems of excess stormwater in urban areas, flooding of farmlands, and flood damages at road crossings. The cumulative costs involved with floods and flood mitigation in Minnesota are not known precisely, but it is safe to conclude that flood mitigation is a costly business. This chapter begins with a description of floods in Minneosta to provide examples and contrasts across the state. Background material is presented to provide a basic understanding of floods and flood processes, predication, and management and mitigation. Methods of analyzing and characterizing floods are presented because they affect how we respond to flooding and can influence relevant practices. The understanding and perceptions of floods and flooding commonly differ among those who work in flood forecasting, flood protection, or water resource mamnagement and citizens and businesses affected by floods. These differences can become magnified following a major flood, pointing to the need for better understanding of flooding as well as common language to describe flood risks and the uncertainty associated with determining such risks. Expectations of accurate and timely flood forecasts and our ability to control floods do not always match reality. Striving for clarity is important in formulating policies that can help avoid recurring flood damages and costs.

Natural hazards on alluvial fans: the debris flow and flash flood disaster of December 1999, Vargas state, Venezuela

Science.gov (United States)

Larsen, Matthew C.; Wieczorek, Gerald F.; Eaton, L.S.; Torres-Sierra, Heriberto; Sylva, Walter F.

2001-01-01

Large populations live on or near alluvial fans in locations such as Los Angeles, California, Salt Lake City, Utah, Denver, Colorado, and lesser known areas such as Sarno, Italy, and Vargas, Venezuela. Debris flows and flash floods occur episodically in these alluvial fan environments, and place many communities at high risk during intense and prolonged rainfall. In December 1999, rainstorms induced thousands of landslides along the Cordillera de la Costa, Vargas, Venezuela. Rainfall accumulation of 293 mm during the first 2 weeks of December was followed by an additional 911 mm of rainfall on December 14 through 16. Debris flows and floods inundated coastal communities resulting in a catastrophic death toll of as many as 30,000 people. Flash floods and debris flows caused severe property destruction on alluvial fans at the mouths of the coastal mountain drainage network. In time scales spanning thousands of years, the alluvial fans along this Caribbean coastline are dynamic zones of high geomorphic activity. Because most of the coastal zone in Vargas consists of steep mountain fronts that rise abruptly from the Caribbean Sea, the alluvial fans provide practically the only flat areas upon which to build. Rebuilding and reoccupation of these areas requires careful determination of hazard zones to avoid future loss of life and property. KEY TERMS: Debris flows, flash floods, alluvial fans, natural hazards, landslides, Venezuela

Flood hazard studies in Central Texas using orbital and suborbital remote sensing machinery

Science.gov (United States)

Baker, V. R.; Holz, R. K.; Patton, P. C.

1975-01-01

Central Texas is subject to infrequent, unusually intense rainstorms which cause extremely rapid runoff from drainage basins developed on the deeply dissected limestone and marl bedrock of the Edwards Plateau. One approach to flood hazard evaluation in this area is a parametric model relating flood hydrograph characteristics to quantitative geomorphic properties of the drainage basins. The preliminary model uses multiple regression techniques to predict potential peak flood discharge from basin magnitude, drainage density, and ruggedness number. After mapping small catchment networks from remote sensing imagery, input data for the model are generated by network digitization and analysis by a computer assisted routine of watershed analysis. The study evaluated the network resolution capabilities of the following data formats: (1) large-scale (1:24,000) topographic maps, employing Strahler's "method of v's," (2) standard low altitude black and white aerial photography (1:13,000 and 1:20,000 scales), (3) NASA - generated aerial infrared photography at scales ranging from 1:48,000 to 1:123,000, and (4) Skylab Earth Resources Experiment Package S-190A and S-190B sensors (1:750,000 and 1:500,000 respectively).

Combining sea state and land subsidence rates in an assessment of flooding hazards at the Danish North Sea coast

DEFF Research Database (Denmark)

Sørensen, Carlo Sass; Broge, Niels; Knudsen, Per

Sand nourishments (2-3 M3/y) counteract erosion on the central North Sea coast of Denmark and dikes and artificial dunes protect the low-lying hinterland from flooding. The fisheries towns of Thyboron, Thorsminde and Hvide Sande are all liable to flooding during storm surges. Tide gauge series fr...... the coast are presented and the town of Thyboron is used as a case where, in addition to SLR and extremes, analyses of land movement and ocean-groundwater interactions are included in an integrated method for assessing future coastal flooding hazards.......Sand nourishments (2-3 M3/y) counteract erosion on the central North Sea coast of Denmark and dikes and artificial dunes protect the low-lying hinterland from flooding. The fisheries towns of Thyboron, Thorsminde and Hvide Sande are all liable to flooding during storm surges. Tide gauge series from...

The development of flood map in Malaysia

Science.gov (United States)

Zakaria, Siti Fairus; Zin, Rosli Mohamad; Mohamad, Ismail; Balubaid, Saeed; Mydin, Shaik Hussein; MDR, E. M. Roodienyanto

2017-11-01

In Malaysia, flash floods are common occurrences throughout the year in flood prone areas. In terms of flood extent, flash floods affect smaller areas but because of its tendency to occur in densely urbanized areas, the value of damaged property is high and disruption to traffic flow and businesses are substantial. However, in river floods especially the river floods of Kelantan and Pahang, the flood extent is widespread and can extend over 1,000 square kilometers. Although the value of property and density of affected population is lower, the damage inflicted by these floods can also be high because the area affected is large. In order to combat these floods, various flood mitigation measures have been carried out. Structural flood mitigation alone can only provide protection levels from 10 to 100 years Average Recurrence Intervals (ARI). One of the economically effective non-structural approaches in flood mitigation and flood management is using a geospatial technology which involves flood forecasting and warning services to the flood prone areas. This approach which involves the use of Geographical Information Flood Forecasting system also includes the generation of a series of flood maps. There are three types of flood maps namely Flood Hazard Map, Flood Risk Map and Flood Evacuation Map. Flood Hazard Map is used to determine areas susceptible to flooding when discharge from a stream exceeds the bank-full stage. Early warnings of incoming flood events will enable the flood victims to prepare themselves before flooding occurs. Properties and life's can be saved by keeping their movable properties above the flood levels and if necessary, an early evacuation from the area. With respect to flood fighting, an early warning with reference through a series of flood maps including flood hazard map, flood risk map and flood evacuation map of the approaching flood should be able to alert the organization in charge of the flood fighting actions and the authority to

SHYREG, a national database of flood frequency estimation

Directory of Open Access Journals (Sweden)

Arnaud Patrick

2016-01-01

Full Text Available SHYREG method is a regionalized method for rainfall and flood frequency analysis (FFA. It is based on processes simulation. It couples an hourly rainfall generator with a rainfall-runoff model, simplified enough to be regionalized. The method has been calibrated using all hydro meteorological data available at the national level. In France, that represents about 2800 raingauges of the French Weather Service network and about 1800 stations of the hydrometric National Bank network. Then, the method has been regionalized to provide a rainfall and flow quantiles database. An evaluation of the method was carried out during different thesis works and more recently during the ANR project Extraflo, with the aim of comparing different FFA approaches. The accuracy of the method in estimating rainfall and flow quantiles has been proved, as well as its stability due to a parameterization based on average values. The link with rainfall seems preferable to extrapolation based solely on the flow. Thus, another interest of the method is to take into account extreme flood behaviour with help of rainfall frequency estimation. In addition, the approach is implicitly multi-durational, and only one regionalization meets all the needs in terms hydrological hazards characterisation. For engineering needs and to avoid repeating the method implementation, this method has been applied throughout a 50 meters resolution mesh to provide a complete flood quantiles database over the French territory providing regional information on hydrological hazards. However, it is subject to restrictions related to the nature of the method: the SHYREG flows are “natural”, and do not take into account specific cases like the basins highly influenced by presence of hydraulic works, flood expansion areas, high snowmelt or karsts. Information about these restrictions and uncertainty estimation is provided with this database, which can be consulted via web access.

A spatiotemporal optimization model for the evacuation of the population exposed to flood hazard

Science.gov (United States)

Alaeddine, H.; Serrhini, K.; Maizia, M.

2015-03-01

Managing the crisis caused by natural disasters, and especially by floods, requires the development of effective evacuation systems. An effective evacuation system must take into account certain constraints, including those related to traffic network, accessibility, human resources and material equipment (vehicles, collecting points, etc.). The main objective of this work is to provide assistance to technical services and rescue forces in terms of accessibility by offering itineraries relating to rescue and evacuation of people and property. We consider in this paper the evacuation of an urban area of medium size exposed to the hazard of flood. In case of inundation, most people will be evacuated using their own vehicles. Two evacuation types are addressed in this paper: (1) a preventive evacuation based on a flood forecasting system and (2) an evacuation during the disaster based on flooding scenarios. The two study sites on which the developed evacuation model is applied are the Tours valley (Fr, 37), which is protected by a set of dikes (preventive evacuation), and the Gien valley (Fr, 45), which benefits from a low rate of flooding (evacuation before and during the disaster). Our goal is to construct, for each of these two sites, a chronological evacuation plan, i.e., computing for each individual the departure date and the path to reach the assembly point (also called shelter) according to a priority list established for this purpose. The evacuation plan must avoid the congestion on the road network. Here we present a spatiotemporal optimization model (STOM) dedicated to the evacuation of the population exposed to natural disasters and more specifically to flood risk.

Base Flood Elevation

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by FEMA, and any Letters Of Map Revision...

STUDY REGARDING DELINEATION OF FLOOD HAZARD ZONES IN THE HYDROGRAPHIC BASIN OF THE SOMEŞ RIVER, BORDER AREA

Directory of Open Access Journals (Sweden)

STOICA F.

2014-03-01

Full Text Available The hydrological studies will provide the characteristic parameters for the floods occurred for the calculus discharges with overflow probabilities of 0,1%; 1%, 5%, 10%. The hydrologic and hydraulic models will be made by using the hydro-meteorological data base and the topographical measurements on site; them calibration will be done according to the records of the historical floods. The studies on the hydrologic and hydraulic models will be necessary for the establishment of the carrying capacity of the riverbeds, for the delimitation of the flood plains and for the detection of the transit discharges at the hydro-technical installations, but also for the establishment of the parameters needed for the structural measures’ projects. These will be based on the 1D and 2D unstable hydro-dynamic models. Therefore, the users would be able to assess the proposed measures and the impact over the river’s system; of course with the potential combination of the 1D and 2D. The main objectives followed by the project are: • identification of the river basins or river sub-basins with flood risks; • regionalization of the flood hazard; • presentation of the main flash floods occurred during the last 30 years, which induced floods; • assessment of the consequences of eventual flood over the population, properties and environment; • the establishment of the protection degree, accepted for the human settlements, for the economic and social objectives, for the farm areas, etc.;

Mitigating flood exposure

Science.gov (United States)

Shultz, James M; McLean, Andrew; Herberman Mash, Holly B; Rosen, Alexa; Kelly, Fiona; Solo-Gabriele, Helena M; Youngs Jr, Georgia A; Jensen, Jessica; Bernal, Oscar; Neria, Yuval

2013-01-01

Introduction. In 2011, following heavy winter snowfall, two cities bordering two rivers in North Dakota, USA faced major flood threats. Flooding was foreseeable and predictable although the extent of risk was uncertain. One community, Fargo, situated in a shallow river basin, successfully mitigated and prevented flooding. For the other community, Minot, located in a deep river valley, prevention was not possible and downtown businesses and one-quarter of the homes were inundated, in the city’s worst flood on record. We aimed at contrasting the respective hazards, vulnerabilities, stressors, psychological risk factors, psychosocial consequences, and disaster risk reduction strategies under conditions where flood prevention was, and was not, possible. Methods. We applied the “trauma signature analysis” (TSIG) approach to compare the hazard profiles, identify salient disaster stressors, document the key components of disaster risk reduction response, and examine indicators of community resilience. Results. Two demographically-comparable communities, Fargo and Minot, faced challenging river flood threats and exhibited effective coordination across community sectors. We examined the implementation of disaster risk reduction strategies in situations where coordinated citizen action was able to prevent disaster impact (hazard avoidance) compared to the more common scenario when unpreventable disaster strikes, causing destruction, harm, and distress. Across a range of indicators, it is clear that successful mitigation diminishes both physical and psychological impact, thereby reducing the trauma signature of the event. Conclusion. In contrast to experience of historic flooding in Minot, the city of Fargo succeeded in reducing the trauma signature by way of reducing risk through mitigation. PMID:28228985

The Impact of Climate Change on New York City's Coastal Flood Hazard: Increasing Flood Heights from the Pre-Industrial to 2300 CE

Science.gov (United States)

Garner, A. J.; Mann, M. E.; Emanuel, K.; Kopp, R. E.; Lin, N.; Alley, R. B.; Horton, B.; Deconto, R. M.; Donnelly, J. P.; Pollard, D.

2017-12-01

The flood hazard in New York City depends on both storm surges and rising sea levels. We combine modeled storm surges with probabilistic sea-level rise projections to assess future coastal inundation in New York City from the pre-industrial through 2300 CE. The storm surges are derived from large sets of synthetic tropical cyclones, downscaled from RCP 8.5 runs of three CMIP5 models. The sea-level rise projections include the collapse of the Antarctic ice sheet to assess future coastal inundation. CMIP5 models indicate that there will be minimal change in storm-surge heights from 2010 to 2100 or 2300, because the predicted strengthening of the strongest storms will be compensated by storm tracks moving offshore at the latitude of New York City. However, projected sea-level rise causes overall flood heights associated with tropical cyclones in New York City in coming centuries to increase greatly compared to pre-industrial or modern flood heights. We find that the 1-in-500-year flood event increases from 3.4 m above mean tidal level during 1970-2005 to 3.9 - 4.8 m above mean tidal level by 2080-2100, and ranges from 2.8 - 13.0 m above mean tidal level by 2280-2300. Further, we find that the return period of a 2.25 m flood has decreased from 500 years prior to 1800 to 25 years during 1970-2005, and further decreases to 5 years by 2030 - 2045 in 95% of our simulations.

iFLOOD: A Real Time Flood Forecast System for Total Water Modeling in the National Capital Region

Science.gov (United States)

Sumi, S. J.; Ferreira, C.

2017-12-01

Extreme flood events are the costliest natural hazards impacting the US and frequently cause extensive damages to infrastructure, disruption to economy and loss of lives. In 2016, Hurricane Matthew brought severe damage to South Carolina and demonstrated the importance of accurate flood hazard predictions that requires the integration of riverine and coastal model forecasts for total water prediction in coastal and tidal areas. The National Weather Service (NWS) and the National Ocean Service (NOS) provide flood forecasts for almost the entire US, still there are service-gap areas in tidal regions where no official flood forecast is available. The National capital region is vulnerable to multi-flood hazards including high flows from annual inland precipitation events and surge driven coastal inundation along the tidal Potomac River. Predicting flood levels on such tidal areas in river-estuarine zone is extremely challenging. The main objective of this study is to develop the next generation of flood forecast systems capable of providing accurate and timely information to support emergency management and response in areas impacted by multi-flood hazards. This forecast system is capable of simulating flood levels in the Potomac and Anacostia River incorporating the effects of riverine flooding from the upstream basins, urban storm water and tidal oscillations from the Chesapeake Bay. Flood forecast models developed so far have been using riverine data to simulate water levels for Potomac River. Therefore, the idea is to use forecasted storm surge data from a coastal model as boundary condition of this system. Final output of this validated model will capture the water behavior in river-estuary transition zone far better than the one with riverine data only. The challenge for this iFLOOD forecast system is to understand the complex dynamics of multi-flood hazards caused by storm surges, riverine flow, tidal oscillation and urban storm water. Automated system

Identification of glacial flood hazards in karakorum range using remote sensing technique and risk analysis

International Nuclear Information System (INIS)

Ashraf, A.; Roohi, R.; Naz, R.

2011-01-01

Glacial Lake Outburst Floods (GLOFs) are great hazard for the downstream communities in context of changing climatic conditions in the glaciated region of Pakistan. The remote sensing data of Landsat ETM+ was utilized for the identification of glacial lakes susceptible to posing GLOF hazard in Karakoram Range. Overall, 887 glacial lakes are identified in different river-basins of Karakoram Range, out of which 16 lakes are characterized as potentially dangerous in terms of GLOF. The analysis of community's response to GLOF events of 2008 in the central Karakoram Range indicated gaps in coordination and capacity of the local communities to cope with such natural hazards. A regular monitoring of hot spots and potential GLOF lakes along with capacity- of local communities and institutions in coping future disaster situation is necessary, especially in the context of changing climatic conditions in Himalayan region. (author)

Trends in flash flood events versus convective precipitation in the Mediterranean region: The case of Catalonia

Science.gov (United States)

Llasat, Maria Carmen; Marcos, Raul; Turco, Marco; Gilabert, Joan; Llasat-Botija, Montserrat

2016-10-01

The aim of this paper is to analyse the potential relationship between flash flood events and convective precipitation in Catalonia, as well as any related trends. The paper starts with an overview of flash floods and their trends in the Mediterranean region, along with their associated factors, followed by the definition of, identification of, and trends in convective precipitation. After this introduction the paper focuses on the north-eastern Iberian Peninsula, for which there is a long-term precipitation series (since 1928) of 1-min precipitation from the Fabra Observatory, as well as a shorter (1996-2011) but more extensive precipitation series (43 rain gauges) of 5-min precipitation. Both series have been used to characterise the degree of convective contribution to rainfall, introducing the β parameter as the ratio between convective precipitation versus total precipitation in any period. Information about flood events was obtained from the INUNGAMA database (a flood database created by the GAMA team), with the aim of finding any potential links to convective precipitation. These flood data were gathered using information on damage where flood is treated as a multifactorial risk, and where any trend or anomaly might have been caused by one or more factors affecting hazard, vulnerability or exposure. Trend analysis has shown an increase in flash flood events. The fact that no trends were detected in terms of extreme values of precipitation on a daily scale, nor on the associated ETCCDI (Expert Team on Climate Change Detection and Indices) extreme index, could point to an increase in vulnerability, an increase in exposure, or changes in land use. However, the summer increase in convective precipitation was concentrated in less torrential events, which could partially explain this positive trend in flash flood events. The β parameter has been also used to characterise the type of flood event according to the features of the precipitation. The highest values

Wastes Characterisation from Foundry Activities on European Level

International Nuclear Information System (INIS)

Andres, I.; Ruiz, C.; Ibanez, R.; Viguri, J.; Irabien, A.

1999-01-01

This work presents The results of the eco toxicological characterisation of 22 defined wastes from steel foundry activities. The wastes have been selected from three processes, steel mill (smelting). sand casting and cleaning and finishing of steel products,with the common characteristics of represent an important industrial activity in the area and generated the wastes considered in this study. The eco toxicological characterisation obtained applying the Spanish regulations on hazardous waste is compared to the hazardous attributions considered by the European Union in order to characterise a waste as hazardous (non hazardous). The results allow to conclude that a acceptable concordance between both methodologies is reached and remark the need to split the broad generic types of wastes given by the Spanish regulation (Eco toxic / non eco toxic) into clearly identifiable specific types of waste

Flood hazard assessment using 1D and 2D approaches

Science.gov (United States)

Petaccia, Gabriella; Costabile, Pierfranco; Macchione, Francesco; Natale, Luigi

2013-04-01

The EU flood risk Directive (Directive 2007/60/EC) prescribes risk assessment and mapping to develop flood risk management plans. Flood hazard mapping may be carried out with mathematical models able to determine flood-prone areas once realistic conditions (in terms of discharge or water levels) are imposed at the boundaries of the case study. The deterministic models are mainly based on shallow water equations expressed in their 1D or 2D formulation. The 1D approach is widely used, especially in technical studies, due to its relative simplicity, its computational efficiency and also because it requires topographical data not as expensive as the ones needed by 2D models. Even if in a great number of practical situations, such as modeling in-channel flows and not too wide floodplains, the 1D approach may provide results close to the prediction of a more sophisticated 2D model, it must be pointed out that the correct use of a 1D model in practical situations is more complex than it may seem. The main issues to be correctly modeled in a 1D approach are the definition of hydraulic structures such as bridges and buildings interacting with the flow and the treatment of the tributaries. Clearly all these aspects have to be taken into account also in the 2D modeling, but with fewer difficulties. The purpose of this paper is to show how the above cited issues can be described using a 1D or 2D unsteady flow modeling. In particular the Authors will show the devices that have to be implemented in 1D modeling to get reliable predictions of water levels and discharges comparable to the ones obtained using a 2D model. Attention will be focused on an actual river (Crati river) located in the South of Italy. This case study is quite complicated since it deals with the simulation of channeled flows, overbank flows, interactions with buildings, bridges and tributaries. Accurate techniques, intentionally developed by the Authors to take into account all these peculiarities in 1D and 2

Flood Modelling of Banjir Kanal Barat (Integration of Hydrology Model and GIS

Directory of Open Access Journals (Sweden)

Muhammad Aris Marfai

2004-01-01

Full Text Available Hydrological modelling has an advantage on river flood study. Hydrological factors can be easily determined and calculated using hydrological model. HEC-RAS (Hydrological Engineering Centre-River Analysis System software is well known as hydrological modelling software for flood simulation and encroachment analysis of the floodplain area. For spatial performance and analysis of flood, the integration of the Geographic Information Systems (GIS and hydrological model is needed. The aims of this research are 1 to perform a flood encroachment using HEC-RAS software, and 2 to generate a flood hazard map. The methodology for this research omprise of 1 generating geometric data as a requirement of the data input on HEC-RAS hydrological model, 2 Hydrological data inputting, 3 generating of the flood encroachment analysis, and 4 transformation of flood encroachment into flood hazard map. The spatial pattern of the flood hazard is illustrated in a map. The result shows that hydrological model as integration with GIS can be used for flood hazard map generation. This method has advantages on the calculation of the hydrological factors of flood and spatial performance of the flood hazard map. For further analysis, the landuse map can be used on the overlay operation with the flood hazard map in order to obtain the impact of the flood on the landuse.

Use of agent-based modelling in emergency management under a range of flood hazards

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Tagg Andrew

2016-01-01

Full Text Available The Life Safety Model (LSM was developed some 15 years ago, originally for dam break assessments and for informing reservoir evacuation and emergency plans. Alongside other technological developments, the model has evolved into a very useful agent-based tool, with many applications for a range of hazards and receptor behaviour. HR Wallingford became involved in its use in 2006, and is now responsible for its technical development and commercialisation. Over the past 10 years the model has been applied to a range of flood hazards, including coastal surge, river flood, dam failure and tsunami, and has been verified against historical events. Commercial software licences are being used in Canada, Italy, Malaysia and Australia. A core group of LSM users and analysts has been specifying and delivering a programme of model enhancements. These include improvements to traffic behaviour at intersections, new algorithms for sheltering in high-rise buildings, and the addition of monitoring points to allow detailed analysis of vehicle and pedestrian movement. Following user feedback, the ability of LSM to handle large model ‘worlds’ and hydrodynamic meshes has been improved. Recent developments include new documentation, performance enhancements, better logging of run-time events and bug fixes. This paper describes some of the recent developments and summarises some of the case study applications, including dam failure analysis in Japan and mass evacuation simulation in England.

Drivers of flood damage on event level

DEFF Research Database (Denmark)

Kreibich, H.; Aerts, J. C. J. H.; Apel, H.

2016-01-01

example are the 2002 and 2013 floods in the Elbe and Danube catchments in Germany. The 2002 flood caused the highest economic damage (EUR 11600 million) due to a natural hazard event in Germany. Damage was so high due to extreme flood hazard triggered by extreme precipitation and a high number......-level mitigation measures, 3) more effective early warning and improved coordination of disaster response and 4) a more targeted maintenance of flood defence systems and their deliberate relocation. Thus, despite higher hydrological severity damage due to the 2013 flood was significantly lower than in 2002. In our...

Development of a customised design flood estimation tool to ...

African Journals Online (AJOL)

The estimation of design flood events, i.e., floods characterised by a specific magnitude-frequency relationship, at a particular site in a specific region is necessary for the planning, design and operation of hydraulic structures. Both the occurrence and frequency of flood events, along with the uncertainty involved in the ...

More frequent flooding? Changes in flood frequency in the Pearl River basin, China, since 1951 and over the past 1000 years

Science.gov (United States)

Zhang, Qiang; Gu, Xihui; Singh, Vijay P.; Shi, Peijun; Sun, Peng

2018-05-01

Flood risks across the Pearl River basin, China, were evaluated using a peak flood flow dataset covering a period of 1951-2014 from 78 stations and historical flood records of the past 1000 years. The generalized extreme value (GEV) model and the kernel estimation method were used to evaluate frequencies and risks of hazardous flood events. Results indicated that (1) no abrupt changes or significant trends could be detected in peak flood flow series at most of the stations, and only 16 out of 78 stations exhibited significant peak flood flow changes with change points around 1990. Peak flood flow in the West River basin increased and significant increasing trends were identified during 1981-2010; decreasing peak flood flow was found in coastal regions and significant trends were observed during 1951-2014 and 1966-2014. (2) The largest three flood events were found to cluster in both space and time. Generally, basin-scale flood hazards can be expected in the West and North River basins. (3) The occurrence rate of floods increased in the middle Pearl River basin but decreased in the lower Pearl River basin. However, hazardous flood events were observed in the middle and lower Pearl River basin, and this is particularly true for the past 100 years. However, precipitation extremes were subject to moderate variations and human activities, such as building of levees, channelization of river systems, and rapid urbanization; these were the factors behind the amplification of floods in the middle and lower Pearl River basin, posing serious challenges for developing measures of mitigation of flood hazards in the lower Pearl River basin, particularly the Pearl River Delta (PRD) region.

Coastal Zone Hazards Related to Groundwater-Surface Water Interactions and Groundwater Flooding

Science.gov (United States)

Kontar, Y. A.; Ozorovich, Y. R.; Salokhiddinov, A. T.

2009-12-01

Worldwide, as many as half a million people have died in natural and man-made disasters since the turn of the 21st century (Wirtz, 2008). Further, natural and man-made hazards can lead to extreme financial losses (Elsner et al, 2009). Hazards, hydrological and geophysical risk analysis related to groundwater-surface water interactions and groundwater flooding have been to a large extent under-emphasized for coastal zone applications either due to economical limitations or underestimation of its significance. This is particularly true for tsunamis creating salt water intrusion to coastal aquifers, even though most tsunami hazard assessments have in the past relied on scenario or deterministic type models (Geist and Parsons, 2006), and to increasing mineralization of potable water because of intensive water diversions and also the abundance of highly toxic pollutants (mainly pesticides) in water, air and food, which contribute to the deterioration of the coastal population's health (Glantz, 2007). In the wake of pressing environmental and economic issues, it is of prime importance for the scientific community to shed light onto the great efforts by hydrologists and geophysicists to quantify conceptual uncertainties and to provide quality assurances of potential coastal zone hazard evaluation and prediction. This paper proposes consideration of two case studies which are important and significant for future development and essential for feasibility studies of hazards in the coastal zone. The territory of the Aral Sea Region in Central Asia is known as an ecological disaster coastal zone (Zavialov, 2005). It is now obvious that, in order to provide reasonable living conditions to the coastal zone population, it is first of all necessary to drastically improve the quality of the water dedicated to human needs. Due to their intensive pollution by industrial wastes and by drainage waters from irrigated fields, the Syr Darya and Amu Darya rivers can no longer be considered

A framework of integrated hydrological and hydrodynamic models using synthetic rainfall for flash flood hazard mapping of ungauged catchments in tropical zones

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W. Lohpaisankrit

2016-05-01

Full Text Available Flash flood hazard maps provide a scientific support to mitigate flash flood risk. The present study develops a practical framework with the help of integrated hydrological and hydrodynamic modelling in order to estimate the potential flash floods. We selected a small pilot catchment which has already suffered from flash floods in the past. This catchment is located in the Nan River basin, northern Thailand. Reliable meteorological and hydrometric data are missing in the catchment. Consequently, the entire upper basin of the main river was modelled with the help of the hydrological modelling system PANTA RHEI. In this basin, three monitoring stations are located along the main river. PANTA RHEI was calibrated and validated with the extreme flood events in June 2011 and July 2008, respectively. The results show a good agreement with the observed discharge data. In order to create potential flash flood scenarios, synthetic rainfall series were derived from temporal rainfall patterns based on the radar-rainfall observation and different rainfall depths from regional rainfall frequency analysis. The temporal rainfall patterns were characterized by catchment-averaged rainfall series selected from 13 rainstorms in 2008 and 2011 within the region. For regional rainfall frequency analysis, the well-known L-moments approach and related criteria were used to examine extremely climatic homogeneity of the region. According to the L-moments approach, Generalized Pareto distribution was recognized as the regional frequency distribution. The synthetic rainfall series were fed into the PANTA RHEI model. The simulated results from PANTA RHEI were provided to a 2-D hydrodynamic model (MEADFLOW, and various simulations were performed. Results from the integrated modelling framework are used in the ongoing study to regionalize and map the spatial distribution of flash flood hazards with four levels of flood severities. As an overall outcome, the presented framework

Coastal flooding in Denmark – future outlook

DEFF Research Database (Denmark)

Sørensen, C.; Knudsen, P.; Andersen, O. B.

2014-01-01

Water loading from all directions due to river discharge, precipitation, groundwater and the sea state (i.e. mean and extreme water levels) need to be carefully considered when dealing with flooding hazards at the coast. Flooding hazard and risk mapping are major topics in low-lying coastal are- ...... this knowledge together to enable a practice-oriented methodology that combines their effects and future sea extremes in hazard and risk mapping and climate change adaptation schemes in Denmark......- as before even considering the adverse effects of climate change and sea level rise (SLR). From an assessment of Danish sea extremes from historical evidence, tide gauge series, and space measurements, we discuss the current and future hazards, exposure, and vulnerability to flooding along the diverse......, land-use, protection measures a.o. that must be taken into account in order to evaluate current and future flooding hazards and management options. We provide examples from Danish case-studies underlining the necessity of including these factors and we outline an interdisciplinary approach to bring...

A Monitoring System for Mountain Flood Geological Hazard Based on Internet of Things

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HUANGFU Zhong-Min

2014-11-01

Full Text Available In order to avoid the shortcomings of the poor real-time data collection and the insufficient information coverage in the traditional geological hazard disaster monitoring measures, this paper designs a monitoring system for mountain flood geological hazard based on the Internet of Things, in which the overall architecture of the system is built, and the design of hardware combined with its driver program for the remote terminal system is presented in detail. This system uses STC12C5A60S2 MCU as the core controller to handle such data as rainfall, groundwater level and displacement of the mountain which are collected by the sensors, and employs GPS module to get the location information. Then the data processed is encapsulated into TCP/IP data packs by GPRS module. Through GPRS accessing the Internet, these data packs are transmitted to the monitoring center. The experimental results show that the system has good reliability, stability and real-time in communication.

Social media for disaster response during floods

Science.gov (United States)

Eilander, D.; van de Vries, C.; Baart, F.; van Swol, R.; Wagemaker, J.; van Loenen, A.

2015-12-01

During floods it is difficult to obtain real-time accurate information about the extent and severity of the hazard. This information is very important for disaster risk reduction management and crisis relief organizations. Currently, real-time information is derived from few sources such as field reports, traffic camera's, satellite images and areal images. However, getting a real-time and accurate picture of the situation on the ground remains difficult. At the same time, people affected by natural hazards increasingly share their observations and their needs through digital media. Unlike conventional monitoring systems, Twitter data contains a relatively large number of real-time ground truth observations representing both physical hazard characteristics and hazard impacts. In the city of Jakarta, Indonesia, the intensity of unique flood related tweets during a flood event, peaked at almost 900 tweets per minute during floods in early 2015. Flood events around the world in 2014/2015 yielded large numbers of flood related tweets: from Philippines (85.000) to Pakistan (82.000) to South-Korea (50.000) to Detroit (20.000). The challenge here is to filter out useful content from this cloud of data, validate these observations and convert them to readily usable information. In Jakarta, flood related tweets often contain information about the flood depth. In a pilot we showed that this type of information can be used for real-time mapping of the flood extent by plotting these observations on a Digital Elevation Model. Uncertainties in the observations were taken into account by assigning a probability to each observation indicating its likelihood to be correct based on statistical analysis of the total population of tweets. The resulting flood maps proved to be correct for about 75% of the neighborhoods in Jakarta. Further cross-validation of flood related tweets against (hydro-) meteorological data is to likely improve the skill of the method.

The use of remote sensing imagery for environmental land use and flood hazard mapping

Science.gov (United States)

Mouat, D. A.; Miller, D. A.; Foster, K. E.

1976-01-01

Flood hazard maps have been constructed for Graham, Yuma, and Yavapai Counties in Arizona using remote sensing techniques. Watershed maps of priority areas were selected on the basis of their interest to the county planning staff and represented areas of imminent or ongoing development and those known to be subject to inundation by storm runoff. Landsat color infrared imagery at scales of 1:1,000,000, 1:500,000, and 1:250,000 was used together with high-altitude aerial photography at scales of 1:120,000 and 1:60,000 to determine drainage patterns and erosional features, soil type, and the extent and type of ground cover. The satellite imagery was used in the form of 70 mm chips for enhancement in a color additive viewer and in all available enlargement modes. Field checking served as the main backup to the interpretations. Areas with high susceptibility to flooding were determined with a high level of confidence from the remotely sensed imagery.

Characterisation of seasonal flood types according to timescales in mixed probability distributions

Science.gov (United States)

Fischer, Svenja; Schumann, Andreas; Schulte, Markus

2016-08-01

When flood statistics are based on annual maximum series (AMS), the sample often contains flood peaks, which differ in their genesis. If the ratios among event types change over the range of observations, the extrapolation of a probability distribution function (pdf) can be dominated by a majority of events that belong to a certain flood type. If this type is not typical for extraordinarily large extremes, such an extrapolation of the pdf is misleading. To avoid this breach of the assumption of homogeneity, seasonal models were developed that differ between winter and summer floods. We show that a distinction between summer and winter floods is not always sufficient if seasonal series include events with different geneses. Here, we differentiate floods by their timescales into groups of long and short events. A statistical method for such a distinction of events is presented. To demonstrate their applicability, timescales for winter and summer floods in a German river basin were estimated. It is shown that summer floods can be separated into two main groups, but in our study region, the sample of winter floods consists of at least three different flood types. The pdfs of the two groups of summer floods are combined via a new mixing model. This model considers that information about parallel events that uses their maximum values only is incomplete because some of the realisations are overlaid. A statistical method resulting in an amendment of statistical parameters is proposed. The application in a German case study demonstrates the advantages of the new model, with specific emphasis on flood types.

Influence of ENSO on coastal flood hazard and exposure at the global-scale

Science.gov (United States)

Muis, S.; Haigh, I. D.; Guimarães Nobre, G.; Aerts, J.; Ward, P.

2017-12-01

The El Niño-Southern Oscillation (ENSO) is the dominant signal of interannual climate variability. The unusually warm (El Niño) and cold (La Niña) oceanic and atmospheric conditions in the tropical Pacific drives interannual variability in both mean and extreme sea levels, which in turn may influence the probabilities and impacts of coastal flooding. We assess the influence of ENSO on coastal flood hazard and exposure using daily timeseries from the Global Time and Surge Reanalysis (GTSR) dataset (Muis et al., 2016). As the GTSR timeseries do not include steric effects (i.e. density differences), we improve the GTSR timeseries by adding steric sea levels. Evaluation against observed sea levels shows that the including steric sea levels leads to a much better representation of the seasonal and interannual variability. We show that sea level anomalies occur during ENSO years with higher sea levels during La Niña in the South-Atlantic, Indian Ocean and the West Pacific, whereas sea levels are lower in the east Pacific. The pattern is generally inversed for El Niño. We also find an effect of ENSO in the number of people exposed to coastal flooding. Although the effect is minor at the global-scale, it may be important for flood risk management to consider at the national or sub national levels. Previous studies at the global-scale have used tide gauge observation to assess the influence of ENSO on extreme sea levels. The advantage of our approach over observations is that GTSR provides a consistent dataset with a full global coverage for the period 1979-2014. This allows us to assess ENSO's influence on sea level extremes anywhere in the world. Furthermore, it enables us to also calculate the impacts of extreme sea levels in terms of coastal flooding and exposed population. ReferencesMuis et al (2016) A global reanalysis of storm surges and extreme sea levels. Nature Communications.7:11969. doi:10.1038/ncomms11969.

Geomorphological method in the elaboration of hazard maps for flash-floods in the municipality of Jucuarán (El Salvador)

Science.gov (United States)

Fernández-Lavado, C.; Furdada, G.; Marqués, M. A.

2007-07-01

This work deals with the elaboration of flood hazard maps. These maps reflect the areas prone to floods based on the effects of Hurricane Mitch in the Municipality of Jucuarán of El Salvador. Stream channels located in the coastal range in the SE of El Salvador flow into the Pacific Ocean and generate alluvial fans. Communities often inhabit these fans can be affected by floods. The geomorphology of these stream basins is associated with small areas, steep slopes, well developed regolite and extensive deforestation. These features play a key role in the generation of flash-floods. This zone lacks comprehensive rainfall data and gauging stations. The most detailed topographic maps are on a scale of 1:25 000. Given that the scale was not sufficiently detailed, we used aerial photographs enlarged to the scale of 1:8000. The effects of Hurricane Mitch mapped on these photographs were regarded as the reference event. Flood maps have a dual purpose (1) community emergency plans, (2) regional land use planning carried out by local authorities. The geomorphological method is based on mapping the geomorphological evidence (alluvial fans, preferential stream channels, erosion and sedimentation, man-made terraces). Following the interpretation of the photographs this information was validated on the field and complemented by eyewitness reports such as the height of water and flow typology. In addition, community workshops were organized to obtain information about the evolution and the impact of the phenomena. The superimposition of this information enables us to obtain a comprehensive geomorphological map. Another aim of the study was the calculation of the peak discharge using the Manning and the paleohydraulic methods and estimates based on geomorphologic criterion. The results were compared with those obtained using the rational method. Significant differences in the order of magnitude of the calculated discharges were noted. The rational method underestimated the

Geomorphological method in the elaboration of hazard maps for flash-floods in the municipality of Jucuarán (El Salvador

Directory of Open Access Journals (Sweden)

C. Fernández-Lavado

2007-07-01

Full Text Available This work deals with the elaboration of flood hazard maps. These maps reflect the areas prone to floods based on the effects of Hurricane Mitch in the Municipality of Jucuarán of El Salvador. Stream channels located in the coastal range in the SE of El Salvador flow into the Pacific Ocean and generate alluvial fans. Communities often inhabit these fans can be affected by floods. The geomorphology of these stream basins is associated with small areas, steep slopes, well developed regolite and extensive deforestation. These features play a key role in the generation of flash-floods. This zone lacks comprehensive rainfall data and gauging stations. The most detailed topographic maps are on a scale of 1:25 000. Given that the scale was not sufficiently detailed, we used aerial photographs enlarged to the scale of 1:8000. The effects of Hurricane Mitch mapped on these photographs were regarded as the reference event. Flood maps have a dual purpose (1 community emergency plans, (2 regional land use planning carried out by local authorities. The geomorphological method is based on mapping the geomorphological evidence (alluvial fans, preferential stream channels, erosion and sedimentation, man-made terraces. Following the interpretation of the photographs this information was validated on the field and complemented by eyewitness reports such as the height of water and flow typology. In addition, community workshops were organized to obtain information about the evolution and the impact of the phenomena. The superimposition of this information enables us to obtain a comprehensive geomorphological map. Another aim of the study was the calculation of the peak discharge using the Manning and the paleohydraulic methods and estimates based on geomorphologic criterion. The results were compared with those obtained using the rational method. Significant differences in the order of magnitude of the calculated discharges were noted. The rational method

Coastal flooding hazard related to storms and coastal evolution in Valdelagrana spit (Cadiz Bay Natural Park, SW Spain)

Science.gov (United States)

Benavente, J.; Del Río, L.; Gracia, F. J.; Martínez-del-Pozo, J. A.

2006-06-01

Mapping of coastal inundation hazard related to storms requires the combination of multiple sources of information regarding meteorological, morphological and dynamic characteristics of both the area at risk and the studied phenomena. Variables such as beach slope, storm wave height or wind speed have traditionally been used, but detailed geomorphological features of the area as well as long-term shoreline evolution trends must also be taken into account in order to achieve more realistic results. This work presents an evaluation of storm flooding hazard in Valdelagrana spit and marshes (SW Spain), considering two types of storm that are characteristic of the area: a modal storm with 1 year of recurrence interval (maximum wave height of 3.3 m), and an extreme storm with 6-10 years of recurrence interval (maximum wave height of 10.6 m), both approaching the coast perpendicularly. After calculating theoretical storm surge elevation, a digital terrain model was made by adjusting topographic data to field work and detailed geomorphological analysis. A model of flooding extent was subsequently developed for each storm type, and then corrected according to the rates of shoreline change in the last decades, which were assessed by means of aerial photographs taking the dune toe as shoreline indicator. Results show that long-term coastline trend represents an important factor in the prediction of flooding extent, since shoreline retreat causes the deterioration of natural coastal defences as dune ridges, thus increasing coastal exposure to high-energy waves. This way, it has been stated that the lack of sedimentary supply plays an important role in spatial variability of inundation extent in Valdelagrana spit. Finally, a hazard map is presented, where calculated coastal retreat rates are employed in order to predict the areas that could be affected by future inundation events.

Hunza Landslide and Monsoon Flooding in Pakistan Call for International Attention to Transboundary Natural Hazards

Science.gov (United States)

Kargel, J. S.; Fink, W.; Furfaro, R.; Leonard, G. J.; Patterson, M.; Glims, Gaphaz

2010-12-01

Two major disasters in Pakistan and innumerable lesser disasters throughout the Himalaya-Karakoram region in 2010 highlight geologic events and extreme weather (perhaps climate change) in affecting the well being of whole nations and commerce and relations between nations. Two chief events in Pakistan include the Jan. 4 rockslide into the Hunza River and the subsequent formation of a natural dam lake (Lake Gojal); and the monsoon precipitation-fed flooding across the Indus Basin. The first event severed Pakistan’s major land link with China. The second event devastated Pakistan’s national land-based transportation infrastructure and agriculture and displaced millions of people. In a country plagued by monsoon-driven floods, the lack of catastrophic breakout of Lake Gojal is welcome. Satellite-based monitoring shows the spillway to be eroding more rapidly (but not alarmingly) under August’s monsoon peak flow. Similar events have occurred before in the region and will occur again. These mega-events in Pakistan should be an alert for all of South Asia, as climate change increases or shifts the hazard environment, encroaching development and urbanization increases the vulnerabilities, and as improved capacity for trans-national commerce breaks down the Himalayan barrier and both promotes new opportunities and possible conflicts. 2010's natural mega-calamities in Pakistan and widespread landsliding and flooding elsewhere in South Asia underscores the subcontinent’s need for a thorough field-, remote sensing-, and modeling-based assessment of the disaster potential related to landslides, glacier surges, extreme monsoon precipitation events, natural glacier and landslide dam lake outbursts, and unseasonal snow melting. The Himalayan-Karakoram region is remarkable for its heterogeneous responses to climate change. For instance, some areas are undergoing rapid glacier recession and stagnation; others are undergoing glacier growth. We take the instance of the

Towards Water Sensitive City: Lesson Learned From Bogor Flood Hazard in 2017

Science.gov (United States)

Ramdhan, Muhammad; Arifin, Hadi Susilo; Suharnoto, Yuli; Tarigan, Suria Darma

2018-02-01

Bogor known as rain city and it's located at an altitude range of 190-330 meters above sea level. In February 2017 Bogor experienced a series of natural disasters related to heavy rainfall that fell during that time. The hazard in the form of flash floods that cause casualties was shocked, due to the location of Bogor city that located in the foothills with a fairly steep slope. There is a problem with the drainage system in the city of Bogor. Australia Indonesia Center in cooperation with Bogor city government held a focus group discussion to seek a permanent solution for the problems and so that similar incidents do not occur in the future.

Spatial variability and potential impacts of climate change on flood and debris flow hazard zone mapping and implications for risk management

Directory of Open Access Journals (Sweden)

H. Staffler

2008-06-01

Full Text Available The main goals of this study were to identify the alpine torrent catchments that are sensitive to climatic changes and to assess the robustness of the methods for the elaboration of flood and debris flow hazard zone maps to specific effects of climate changes. In this study, a procedure for the identification and localization of torrent catchments in which the climate scenarios will modify the hazard situation was developed. In two case studies, the impacts of a potential increase of precipitation intensities to the delimited hazard zones were studied.

The identification and localization of the torrent and river catchments, where unfavourable changes in the hazard situation occur, could eliminate speculative and unnecessary measures against the impacts of climate changes like a general enlargement of hazard zones or a general over dimensioning of protection structures for the whole territory. The results showed a high spatial variability of the sensitivity of catchments to climate changes. In sensitive catchments, the sediment management in alpine torrents will meet future challenges due to a higher rate for sediment removal from retention basins. The case studies showed a remarkable increase of the areas affected by floods and debris flow when considering possible future precipitation intensities in hazard mapping. But, the calculated increase in extent of future hazard zones lay within the uncertainty of the methods used today for the delimitation of the hazard zones. Thus, the consideration of the uncertainties laying in the methods for the elaboration of hazard zone maps in the torrent and river catchments sensitive to climate changes would provide a useful instrument for the consideration of potential future climate conditions. The study demonstrated that weak points in protection structures in future will become more important in risk management activities.

Projected 21st century coastal flooding in the Southern California Bight. Part 2: Tools for assessing climate change-driven coastal hazards and socio-economic impacts

Science.gov (United States)

Erikson, Li; Barnard, Patrick; O'Neill, Andrea; Wood, Nathan J.; Jones, Jeanne M.; Finzi Hart, Juliette; Vitousek, Sean; Limber, Patrick; Hayden, Maya; Fitzgibbon, Michael; Lovering, Jessica; Foxgrover, Amy C.

2018-01-01

This paper is the second of two that describes the Coastal Storm Modeling System (CoSMoS) approach for quantifying physical hazards and socio-economic hazard exposure in coastal zones affected by sea-level rise and changing coastal storms. The modelling approach, presented in Part 1, downscales atmospheric global-scale projections to local scale coastal flood impacts by deterministically computing the combined hazards of sea-level rise, waves, storm surges, astronomic tides, fluvial discharges, and changes in shoreline positions. The method is demonstrated through an application to Southern California, United States, where the shoreline is a mix of bluffs, beaches, highly managed coastal communities, and infrastructure of high economic value. Results show that inclusion of 100-year projected coastal storms will increase flooding by 9–350% (an additional average 53.0 ± 16.0 km2) in addition to a 25–500 cm sea-level rise. The greater flooding extents translate to a 55–110% increase in residential impact and a 40–90% increase in building replacement costs. To communicate hazards and ranges in socio-economic exposures to these hazards, a set of tools were collaboratively designed and tested with stakeholders and policy makers; these tools consist of two web-based mapping and analytic applications as well as virtual reality visualizations. To reach a larger audience and enhance usability of the data, outreach and engagement included workshop-style trainings for targeted end-users and innovative applications of the virtual reality visualizations.

2013 FEMA Flood Control Structures

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — The National Flood Hazard Layer (NFHL) data incorporates all Digital Flood Insurance Rate Map(DFIRM) databases published by FEMA, and any Letters Of Map Revision...

44 CFR 78.5 - Flood Mitigation Plan development.

Science.gov (United States)

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood Mitigation Plan..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.5 Flood Mitigation Plan development. A Flood Mitigation Plan will articulate a...

Flood risk management in the Souss watershed

Science.gov (United States)

Bouaakkaz, Brahim; El Abidine El Morjani, Zine; Bouchaou, Lhoussaine; Elhimri, Hamza

2018-05-01

Flooding is the most devasting natural hazards that causes more damage throughout the world. In 2016, for the fourth year in a row, it was the most costly natural disaster, in terms of global economic losses: 62 billion, according to a Benfield's 2016 annual report on climate and natural disasters [1]. The semi-arid to arid Souss watershed is vulnerable to floods, whose the intensity is becoming increasingly alarming and this area does not escape to the effects of this extreme event.. Indeed, the susceptibility of this region to this type of hazard is accentuated by its rapid evolution in terms of demography, uncontrolled land use, anthropogenic actions (uncontrolled urbanization, encroachment of the hydraulic public domain, overgrazing, clearing and deforestation).), and physical behavior of the environment (higher slope, impermeable rocks, etc.). It is in this context, that we have developed a strategic plan of action to manage this risk in the Souss basin in order to reduce the human, economic and environmental losses, after the modeling of the flood hazard in the study area, using georeferenced information systems (GIS), satellite remote sensing space and multi-criteria analysis techniques, as well as the history of major floods. This study, which generated the high resolution 30m flood hazard spatial distribution map of with accuracy of 85%, represents a decision tool to identify and prioririze area with high probability of hazard occurrence. It can also serve as a basis for urban evacuation plans for anticipating and preventing flood risk in the region, in order to ovoid any dramatic disaster.

Floods and climate: emerging perspectives for flood risk assessment and management

DEFF Research Database (Denmark)

Merz, B.; Aerts, J.; Arnbjerg-Nielsen, Karsten

2014-01-01

context of floods. We come to the following conclusions: (1) extending the traditional system boundaries (local catchment, recent decades, hydrological/hydraulic processes) opens up exciting possibilities for better understanding and improved tools for flood risk assessment and management. (2) Statistical......, and this variation may be partially quantifiable and predictable, with the perspective of dynamic, climate-informed flood risk management. (4) Efforts are needed to fully account for factors that contribute to changes in all three risk components (hazard, exposure, vulnerability) and to better understand......Flood estimation and flood management have traditionally been the domain of hydrologists, water resources engineers and statisticians, and disciplinary approaches abound. Dominant views have been shaped; one example is the catchment perspective: floods are formed and influenced by the interaction...

Framing 100-year overflowing and overtopping marine submersion hazard resulting from the propagation of 100-year joint hydrodynamic conditions

Science.gov (United States)

Nicolae Lerma, A.; Bulteau, T.; Elineau, S.; Paris, F.; Pedreros, R.

2016-12-01

Marine submersion is an increasing concern for coastal cities as urban development reinforces their vulnerabilities while climate change is likely to foster the frequency and magnitude of submersions. Characterising the coastal flooding hazard is therefore of paramount importance to ensure the security of people living in such places and for coastal planning. A hazard is commonly defined as an adverse phenomenon, often represented by a magnitude of a variable of interest (e.g. flooded area), hereafter called response variable, associated with a probability of exceedance or, alternatively, a return period. Characterising the coastal flooding hazard consists in finding the correspondence between the magnitude and the return period. The difficulty lies in the fact that the assessment is usually performed using physical numerical models taking as inputs scenarios composed by multiple forcing conditions that are most of the time interdependent. Indeed, a time series of the response variable is usually not available so we have to deal instead with time series of forcing variables (e.g. water level, waves). Thus, the problem is twofold: on the one hand, the definition of scenarios is a multivariate matter; on the other hand, it is tricky and approximate to associate the resulting response, being the output of the physical numerical model, to the return period defined for the scenarios. In this study, we illustrate the problem on the district of Leucate, located in the French Mediterranean coast. A multivariate extreme value analysis of waves and water levels is performed offshore using a conditional extreme model, then two different methods are used to define and select 100-year scenarios of forcing variables: one based on joint exceedance probability contours, a method classically used in coastal risks studies, the other based on environmental contours, which are commonly used in the field of structure design engineering. We show that these two methods enable one to

Validation of a Global Hydrodynamic Flood Inundation Model

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Bates, P. D.; Smith, A.; Sampson, C. C.; Alfieri, L.; Neal, J. C.

2014-12-01

In this work we present first validation results for a hyper-resolution global flood inundation model. We use a true hydrodynamic model (LISFLOOD-FP) to simulate flood inundation at 1km resolution globally and then use downscaling algorithms to determine flood extent and depth at 90m spatial resolution. Terrain data are taken from a custom version of the SRTM data set that has been processed specifically for hydrodynamic modelling. Return periods of flood flows along the entire global river network are determined using: (1) empirical relationships between catchment characteristics and index flood magnitude in different hydroclimatic zones derived from global runoff data; and (2) an index flood growth curve, also empirically derived. Bankful return period flow is then used to set channel width and depth, and flood defence impacts are modelled using empirical relationships between GDP, urbanization and defence standard of protection. The results of these simulations are global flood hazard maps for a number of different return period events from 1 in 5 to 1 in 1000 years. We compare these predictions to flood hazard maps developed by national government agencies in the UK and Germany using similar methods but employing detailed local data, and to observed flood extent at a number of sites including St. Louis, USA and Bangkok in Thailand. Results show that global flood hazard models can have considerable skill given careful treatment to overcome errors in the publicly available data that are used as their input.

Comparing the Performance of Commonly Available Digital Elevation Models in GIS-based Flood Simulation

Science.gov (United States)

Ybanez, R. L.; Lagmay, A. M. A.; David, C. P.

2016-12-01

With climatological hazards increasing globally, the Philippines is listed as one of the most vulnerable countries in the world due to its location in the Western Pacific. Flood hazards mapping and modelling is one of the responses by local government and research institutions to help prepare for and mitigate the effects of flood hazards that constantly threaten towns and cities in floodplains during the 6-month rainy season. Available digital elevation maps, which serve as the most important dataset used in 2D flood modelling, are limited in the Philippines and testing is needed to determine which of the few would work best for flood hazards mapping and modelling. Two-dimensional GIS-based flood modelling with the flood-routing software FLO-2D was conducted using three different available DEMs from the ASTER GDEM, the SRTM GDEM, and the locally available IfSAR DTM. All other parameters kept uniform, such as resolution, soil parameters, rainfall amount, and surface roughness, the three models were run over a 129-sq. kilometer watershed with only the basemap varying. The output flood hazard maps were compared on the basis of their flood distribution, extent, and depth. The ASTER and SRTM GDEMs contained too much error and noise which manifested as dissipated and dissolved hazard areas in the lower watershed where clearly delineated flood hazards should be present. Noise on the two datasets are clearly visible as erratic mounds in the floodplain. The dataset which produced the only feasible flood hazard map is the IfSAR DTM which delineates flood hazard areas clearly and properly. Despite the use of ASTER and SRTM with their published resolution and accuracy, their use in GIS-based flood modelling would be unreliable. Although not as accessible, only IfSAR or better datasets should be used for creating secondary products from these base DEM datasets. For developing countries which are most prone to hazards, but with limited choices for basemaps used in hazards

Long-term entrenchment and consequences in present flood hazard in Garona River (Val d'Aran, central Pyrenees)

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Victoriano-Lamariano, Ane; Garcia-Silvestre, Marta; Furdada-Bellavista, Gloria

2015-04-01

Flood risk is one of the most dangerous natural disasters in mountainous areas. Risk management and mitigation have to be based on exhaustive risk evaluation. Moreover, hazard analysis requires a multidisciplinary approach to achieve a complete understanding of the dynamics of the phenomena. The Val d'Aran valley is located in the axial part of the Pyrenees and is drained by the Garona River. Flooding events are relatively frequent there. The last extraordinary episode occurred in June 2013. Considering both the main effects of this flooding and the geomorphology, the long-term dynamics of the Garona River was studied in two different areas (Arties-Vielha and Era Bordeta-Les), which are representative of the whole length along the Val d'Aran. In fact, present short-term processes can be partly explained as a result of the long-term fluvial tendency. During the analysis of the 2013 flood effects, several entrenchment and incision indicators were found. Under the hypothesis that the fluvial network tends to incise, an entrenchment indicator analysis was carried out. Firstly, we considered the geomorphologic features, such as two generations of alluvial fans, two generations of alluvial terraces and, incisions on geomorphologic features and in Paleozoic bedrock. Secondly, we found out that erosion dominated over overflow and deposition during the 2013 flooding. Finally, great erosion was identified in engineering structures, for instance, in bridges, channelization dikes, gauging stations and dams. The geomorphologic analysis and the entrenchment indicators are essential to perform a post-glacial evolution interpretation. During the last Pleistocene glacial retreat, a fluvio-torrential network was developed at the bottom of the ancient glacial valley. An early post-glacial phase with a high sediment transport lead to the formation of first generation alluvial fans and alluvial terraces (nowadays located ≈15m above the channel). As sediment transport decreased

A framework for global river flood risk assessments

Science.gov (United States)

Winsemius, H. C.; Van Beek, L. P. H.; Jongman, B.; Ward, P. J.; Bouwman, A.

2013-05-01

There is an increasing need for strategic global assessments of flood risks in current and future conditions. In this paper, we propose a framework for global flood risk assessment for river floods, which can be applied in current conditions, as well as in future conditions due to climate and socio-economic changes. The framework's goal is to establish flood hazard and impact estimates at a high enough resolution to allow for their combination into a risk estimate, which can be used for strategic global flood risk assessments. The framework estimates hazard at a resolution of ~ 1 km2 using global forcing datasets of the current (or in scenario mode, future) climate, a global hydrological model, a global flood-routing model, and more importantly, an inundation downscaling routine. The second component of the framework combines hazard with flood impact models at the same resolution (e.g. damage, affected GDP, and affected population) to establish indicators for flood risk (e.g. annual expected damage, affected GDP, and affected population). The framework has been applied using the global hydrological model PCR-GLOBWB, which includes an optional global flood routing model DynRout, combined with scenarios from the Integrated Model to Assess the Global Environment (IMAGE). We performed downscaling of the hazard probability distributions to 1 km2 resolution with a new downscaling algorithm, applied on Bangladesh as a first case study application area. We demonstrate the risk assessment approach in Bangladesh based on GDP per capita data, population, and land use maps for 2010 and 2050. Validation of the hazard estimates has been performed using the Dartmouth Flood Observatory database. This was done by comparing a high return period flood with the maximum observed extent, as well as by comparing a time series of a single event with Dartmouth imagery of the event. Validation of modelled damage estimates was performed using observed damage estimates from the EM

A framework for global river flood risk assessments

Directory of Open Access Journals (Sweden)

H. C. Winsemius

2013-05-01

Full Text Available There is an increasing need for strategic global assessments of flood risks in current and future conditions. In this paper, we propose a framework for global flood risk assessment for river floods, which can be applied in current conditions, as well as in future conditions due to climate and socio-economic changes. The framework's goal is to establish flood hazard and impact estimates at a high enough resolution to allow for their combination into a risk estimate, which can be used for strategic global flood risk assessments. The framework estimates hazard at a resolution of ~ 1 km2 using global forcing datasets of the current (or in scenario mode, future climate, a global hydrological model, a global flood-routing model, and more importantly, an inundation downscaling routine. The second component of the framework combines hazard with flood impact models at the same resolution (e.g. damage, affected GDP, and affected population to establish indicators for flood risk (e.g. annual expected damage, affected GDP, and affected population. The framework has been applied using the global hydrological model PCR-GLOBWB, which includes an optional global flood routing model DynRout, combined with scenarios from the Integrated Model to Assess the Global Environment (IMAGE. We performed downscaling of the hazard probability distributions to 1 km2 resolution with a new downscaling algorithm, applied on Bangladesh as a first case study application area. We demonstrate the risk assessment approach in Bangladesh based on GDP per capita data, population, and land use maps for 2010 and 2050. Validation of the hazard estimates has been performed using the Dartmouth Flood Observatory database. This was done by comparing a high return period flood with the maximum observed extent, as well as by comparing a time series of a single event with Dartmouth imagery of the event. Validation of modelled damage estimates was performed using observed damage estimates from

Assessing flash flood vulnerability using a multi-vulnerability approach

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Karagiorgos Konstantinos

2016-01-01

Full Text Available In the framework of flood risk assessment, while the understanding of hazard and exposure has significantly improved over the last years, knowledge on vulnerability remains one of the challenges. Current approaches in vulnerability research are characterised by a division between social scientists and natural scientists. In order to close this gap, we present an approach that combines information on physical and social vulnerability in order to merge information on the susceptibility of elements at risk and society. With respect to physical vulnerability, the study is based on local-scale vulnerability models using nonlinear regression approaches. Modified Weibull distributions were fit to the data in order to represent the relationship between process magnitude and degree of loss. With respect to social vulnerability we conducted a door-to-door survey which resulted in particular insights on flood risk awareness and resilience strategies of exposed communities. In general, both physical and social vulnerability were low in comparison with other European studies, which may result from (a specific building regulations in the four Mediterranean test sites as well as general design principles leading to low structural susceptibility of elements at risk, and (b relatively low social vulnerability of citizens exposed. As a result it is shown that a combination of different perspectives of vulnerability will lead to a better understanding of exposure and capacities in flood risk management.

THE FLOOD RISK IN THE LOWER GIANH RIVER: MODELLING AND FIELD VERIFICATION

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NGUYEN H. D.

2016-03-01

Full Text Available Problems associated with flood risk definitely represent a highly topical issue in Vietnam. The case of the lower Gianh River in the central area of Vietnam, with a watershed area of 353 km2, is particularly interesting. In this area, periodically subject to flood risk, the scientific question is strongly linked to risk management. In addition, flood risk is the consequence of the hydrological hazard of an event and the damages related to this event. For this reason, our approach is based on hydrodynamic modelling using Mike Flood to simulate the runoff during a flood event. Unfortunately the data in the studied area are quite limited. Our computation of the flood risk is based on a three-step modelling process, using rainfall data coming from 8 stations, cross sections, the topographic map and the land-use map. The first step consists of creating a 1-D model using Mike 11, in order to simulate the runoff in the minor river bed. In the second step, we use Mike 21 to create a 2-D model to simulate the runoff in the flood plain. The last step allows us to couple the two models in order to precisely describe the variables for the hazard analysis in the flood plain (the water level, the speed, the extent of the flooding. Moreover the model is calibrated and verified using observational data of the water level at hydrologic stations and field control data (on the one hand flood height measurements, on the other hand interviews with the community and with the local councillors. We then generate GIS maps in order to improve flood hazard management, which allows us to create flood hazard maps by coupling the flood plain map and the runoff speed map. Our results show that: the flood peak, caused by typhoon Nari, reached more than 6 m on October 16th 2013 at 4 p.m. (its area was extended by 149 km². End that the typhoon constitutes an extreme flood hazard for 11.39%, very high for 10.60%, high for 30.79%, medium for 31.91% and a light flood hazard for 15

Disseminating near-real-time hazards information and flood maps in the Philippines through Web-GIS.

Science.gov (United States)

A Lagmay, Alfredo Mahar Francisco; Racoma, Bernard Alan; Aracan, Ken Adrian; Alconis-Ayco, Jenalyn; Saddi, Ivan Lester

2017-09-01

The Philippines being a locus of tropical cyclones, tsunamis, earthquakes and volcanic eruptions, is a hotbed of disasters. These natural hazards inflict loss of lives and costly damage to property. Situated in a region where climate and geophysical tempest is common, the Philippines will inevitably suffer from calamities similar to those experienced recently. With continued development and population growth in hazard prone areas, it is expected that damage to infrastructure and human losses would persist and even rise unless appropriate measures are immediately implemented by government. In 2012, the Philippines launched a responsive program for disaster prevention and mitigation called the Nationwide Operational Assessment of Hazards (Project NOAH), specifically for government warning agencies to be able to provide a 6hr lead-time warning to vulnerable communities against impending floods and to use advanced technology to enhance current geo-hazard vulnerability maps. To disseminate such critical information to as wide an audience as possible, a Web-GIS using mashups of freely available source codes and application program interface (APIs) was developed and can be found in the URLs http://noah.dost.gov.ph and http://noah.up.edu.ph/. This Web-GIS tool is now heavily used by local government units in the Philippines in their disaster prevention and mitigation efforts and can be replicated in countries that have a proactive approach to address the impacts of natural hazards but lack sufficient funds. Copyright © 2017. Published by Elsevier B.V.

Recent changes in flood damage in the United States from observations and ACME model

Science.gov (United States)

Leng, G.; Leung, L. R.

2017-12-01

Despite efforts to mitigate flood hazards in flood-prone areas, survey- and report-based flood databases show that flood damage has increased and emerged as one of the most costly disaster in the United States since the 1990s. Understanding the mechanism driving the changes in flood damage is therefore critical for reducing flood risk. In this study, we first conduct a comprehensive analysis of the changing characteristics of flood damage at local, state and country level. Results show a significant increasing trend in the number of flood hazards, causing economic losses of up to $7 billion per year. The ratio of flood events that caused tangible economical cost to the total flood events has exhibited a non-significant increasing trend before 2007 followed by a significant decrease, indicating a changing vulnerability to floods. Analysis also reveals distinct spatial and temporal patterns in the threshold intensity of flood hazards with tangible economical cost. To understand the mechanism behind the increasing flood damage, we develop a flood damage economic model coupled with the integrated hydrological modeling system of ACME that features a river routing model with an inundation parameterization and a water use and regulation model. The model is evaluated over the country against historical records. Several numerical experiments are then designed to explore the mechanisms behind the recent changes in flood damage from the perspective of flood hazard, exposure and vulnerability, which constitute flood damage. The role of human activities such as reservoir operations and water use in modifying regional floods are also explored using the new tool, with the goal of improving understanding and modeling of vulnerability to flood hazards.

44 CFR 78.6 - Flood Mitigation Plan approval process.

Science.gov (United States)

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood Mitigation Plan..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION ASSISTANCE § 78.6 Flood Mitigation Plan approval process. The State POC will forward all Flood...

Spatial Analysis of Land Subsidence and Flood Pattern Based on DInSAR Method in Sentinel Sar Imagery and Weighting Method in Geo-Hazard Parameters Combination in North Jakarta Region

Science.gov (United States)

Prasetyo, Y.; Yuwono, B. D.; Ramadhanis, Z.

2018-02-01

The reclamation program carried out in most cities in North Jakarta is directly adjacent to the Jakarta Bay. Beside this program, the density of population and development center in North Jakarta office has increased the need for underground water excessively. As a result of these things, land subsidence in North Jakarta area is relatively high and so intense. The research methodology was developed based on the method of remote sensing and geographic information systems, expected to describe the spatial correlation between the land subsidence and flood phenomenon in North Jakarta. The DInSAR (Differential Interferometric Synthetic Aperture Radar) method with satellite image data Radar (SAR Sentinel 1A) for the years 2015 to 2016 acquisitions was used in this research. It is intended to obtain a pattern of land subsidence in North Jakarta and then combined with flood patterns. For the preparation of flood threat zoning pattern, this research has been modeling in spatial technique based on a weighted parameter of rainfall, elevation, flood zones and land use. In the final result, we have obtained a flood hazard zonation models then do the overlap against DInSAR processing results. As a result of the research, Geo-hazard modelling has a variety results as: 81% of flood threat zones consist of rural area, 12% consists of un-built areas and 7% consists of water areas. Furthermore, the correlation of land subsidence to flood risk zone is divided into three levels of suitability with 74% in high class, 22% in medium class and 4% in low class. For the result of spatial correlation area between land subsidence and flood risk zone are 77% detected in rural area, 17% detected in un-built area and 6% detected in a water area. Whereas the research product is the geo-hazard maps in North Jakarta as the basis of the spatial correlation analysis between the land subsidence and flooding phenomena.double point.

Aligning Natural Resource Conservation and Flood Hazard Mitigation in California.

Science.gov (United States)

Calil, Juliano; Beck, Michael W; Gleason, Mary; Merrifield, Matthew; Klausmeyer, Kirk; Newkirk, Sarah

2015-01-01

Flooding is the most common and damaging of all natural disasters in the United States, and was a factor in almost all declared disasters in U.S. Direct flood losses in the U.S. in 2011 totaled $8.41 billion and flood damage has also been on the rise globally over the past century. The National Flood Insurance Program paid out more than $38 billion in claims since its inception in 1968, more than a third of which has gone to the one percent of policies that experienced multiple losses and are classified as "repetitive loss." During the same period, the loss of coastal wetlands and other natural habitat has continued, and funds for conservation and restoration of these habitats are very limited. This study demonstrates that flood losses could be mitigated through action that meets both flood risk reduction and conservation objectives. We found that there are at least 11,243km2 of land in coastal California, which is both flood-prone and has natural resource conservation value, and where a property/structure buyout and habitat restoration project could meet multiple objectives. For example, our results show that in Sonoma County, the extent of land that meets these criteria is 564km2. Further, we explore flood mitigation grant programs that can be a significant source of funds to such projects. We demonstrate that government funded buyouts followed by restoration of targeted lands can support social, environmental, and economic objectives: reduction of flood exposure, restoration of natural resources, and efficient use of limited governmental funds.

Aligning Natural Resource Conservation and Flood Hazard Mitigation in California.

Directory of Open Access Journals (Sweden)

Juliano Calil

Full Text Available Flooding is the most common and damaging of all natural disasters in the United States, and was a factor in almost all declared disasters in U.S.Direct flood losses in the U.S. in 2011 totaled $8.41 billion and flood damage has also been on the rise globally over the past century. The National Flood Insurance Program paid out more than $38 billion in claims since its inception in 1968, more than a third of which has gone to the one percent of policies that experienced multiple losses and are classified as "repetitive loss." During the same period, the loss of coastal wetlands and other natural habitat has continued, and funds for conservation and restoration of these habitats are very limited. This study demonstrates that flood losses could be mitigated through action that meets both flood risk reduction and conservation objectives. We found that there are at least 11,243km2 of land in coastal California, which is both flood-prone and has natural resource conservation value, and where a property/structure buyout and habitat restoration project could meet multiple objectives. For example, our results show that in Sonoma County, the extent of land that meets these criteria is 564km2. Further, we explore flood mitigation grant programs that can be a significant source of funds to such projects. We demonstrate that government funded buyouts followed by restoration of targeted lands can support social, environmental, and economic objectives: reduction of flood exposure, restoration of natural resources, and efficient use of limited governmental funds.

The Total Risk Analysis of Large Dams under Flood Hazards

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Yu Chen

2018-02-01

Full Text Available Dams and reservoirs are useful systems in water conservancy projects; however, they also pose a high-risk potential for large downstream areas. Flood, as the driving force of dam overtopping, is the main cause of dam failure. Dam floods and their risks are of interest to researchers and managers. In hydraulic engineering, there is a growing tendency to evaluate dam flood risk based on statistical and probabilistic methods that are unsuitable for the situations with rare historical data or low flood probability, so a more reasonable dam flood risk analysis method with fewer application restrictions is needed. Therefore, different from previous studies, this study develops a flood risk analysis method for large dams based on the concept of total risk factor (TRF used initially in dam seismic risk analysis. The proposed method is not affected by the adequacy of historical data or the low probability of flood and is capable of analyzing the dam structure influence, the flood vulnerability of the dam site, and downstream risk as well as estimating the TRF of each dam and assigning corresponding risk classes to each dam. Application to large dams in the Dadu River Basin, Southwestern China, demonstrates that the proposed method provides quick risk estimation and comparison, which can help local management officials perform more detailed dam safety evaluations for useful risk management information.

A GIS based approach for the prediction of the dam break flood hazard – A case study of Zardezas reservoir “Skikda, Algeria”

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Derdous Oussama

2015-12-01

Full Text Available The construction of dams in rivers can offer many advantages, however the consequences resulting from their failure could result in major damage, including loss of life and property destruction. To mitigate the threats of dam break it is essential to appreciate the characteristics of the potential flood in realistic manner. In this study an approach based on the integration of hydraulic modelling and GIS has been used to assess the risks resulting from a potential failure of Zardezas dam, a concrete dam located in Skikda, in the North East of Algeria. HEC-GeoRAS within GIS was used to extract geometric information from a digital elevation model and then imported into HEC-RAS. Flow simulation of the dam break was performed using HEC-RAS and results were mapped using the GIS. Finally, a flood hazard map based on water depth and flow velocity maps was created in GIS environment. According to this map the potential failure of Zardezas dam will place a large number in people in danger. The present study has shown that Application of Geographical Information System (GIS techniques in integration with hydraulic modelling can significantly reduce the time and the resources required to forecast potential dam break flood hazard which can play a crucial role in improving both flood disaster management and land use planning downstream of dams.

44 CFR 61.17 - Group Flood Insurance Policy.

Science.gov (United States)

2010-10-01

... U.S.C. 5174) of an Individuals and Households Program (IHP) award for flood damage as a result of... flood-damage losses sustained by the insured property in the course of any subsequent flooding event..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE...

Review of the flood risk management system in Germany after the major flood in 2013

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Annegret H. Thieken

2016-06-01

Full Text Available Widespread flooding in June 2013 caused damage costs of €6 to 8 billion in Germany, and awoke many memories of the floods in August 2002, which resulted in total damage of €11.6 billion and hence was the most expensive natural hazard event in Germany up to now. The event of 2002 does, however, also mark a reorientation toward an integrated flood risk management system in Germany. Therefore, the flood of 2013 offered the opportunity to review how the measures that politics, administration, and civil society have implemented since 2002 helped to cope with the flood and what still needs to be done to achieve effective and more integrated flood risk management. The review highlights considerable improvements on many levels, in particular (1 an increased consideration of flood hazards in spatial planning and urban development, (2 comprehensive property-level mitigation and preparedness measures, (3 more effective flood warnings and improved coordination of disaster response, and (4 a more targeted maintenance of flood defense systems. In 2013, this led to more effective flood management and to a reduction of damage. Nevertheless, important aspects remain unclear and need to be clarified. This particularly holds for balanced and coordinated strategies for reducing and overcoming the impacts of flooding in large catchments, cross-border and interdisciplinary cooperation, the role of the general public in the different phases of flood risk management, as well as a transparent risk transfer system. Recurring flood events reveal that flood risk management is a continuous task. Hence, risk drivers, such as climate change, land-use changes, economic developments, or demographic change and the resultant risks must be investigated at regular intervals, and risk reduction strategies and processes must be reassessed as well as adapted and implemented in a dialogue with all stakeholders.

The flash flood of October 2011 in the Magra River basin (Italy): rainstorm characterisation and flood response analysis

Science.gov (United States)

Marchi, Lorenzo; Boni, Giorgio; Cavalli, Marco; Comiti, Francesco; Crema, Stefano; Lucía, Ana; Marra, Francesco; Zoccatelli, Davide

2013-04-01

On 25 October 2011, the Magra River, a stream of northwest Italy outflowing into the Ligurian Sea, was affected by a flash flood, which caused severe economic damage and loss of lives. The catchment covers an area of 1717 km2, of which 605 km2 are drained by the Vara River, the major tributary of the Magra River. The flood was caused by an intense rainstorm which lasted approximately 20 hours. The most intense phase lasted about 8 hours, with rainfall amounts up to around 500 mm. The largest rainfall depths (greater than 300 mm) occurred in a narrow southwest - northeast oriented belt covering an area of approximately 400 km2. This flash flood was studied by analysing rainstorm characteristics, runoff response and geomorphic effects. The rainfall fields used in the analysis are based on data from the Settepani weather radar antenna (located at around 100 km from the study basin) and the local rain gauge network. Radar observations and raingauge data were merged to obtain rainfall estimates at 30 min with a resolution of 1 km2. River stage and discharge rating curves are available for few cross-sections on the main channels. Post-flood documentation includes the reconstruction of peak discharge by means of topographic surveys and application of the slope-conveyance method in 34 cross-sections, observations on the geomorphic effects of the event - both in the channel network and on the hillslopes - and the assessment of the timing of the flood based on interviews to eyewitnesses. Regional authorities and local administrations contributed to the documentation of the flood by providing hydrometeorological data, civil protection volunteers accounts, photos and videos recorded during and immediately after the flood. A spatially distributed rainfall-runoff model, fed with rainfall estimates obtained by the radar-derived observations, was used to check the consistency of field-derived peak discharges and to derive the time evolution of the flood. The assessment of unit

An experimental system for flood risk forecasting at global scale

Science.gov (United States)

Alfieri, L.; Dottori, F.; Kalas, M.; Lorini, V.; Bianchi, A.; Hirpa, F. A.; Feyen, L.; Salamon, P.

2016-12-01

Global flood forecasting and monitoring systems are nowadays a reality and are being applied by an increasing range of users and practitioners in disaster risk management. Furthermore, there is an increasing demand from users to integrate flood early warning systems with risk based forecasts, combining streamflow estimations with expected inundated areas and flood impacts. To this end, we have developed an experimental procedure for near-real time flood mapping and impact assessment based on the daily forecasts issued by the Global Flood Awareness System (GloFAS). The methodology translates GloFAS streamflow forecasts into event-based flood hazard maps based on the predicted flow magnitude and the forecast lead time and a database of flood hazard maps with global coverage. Flood hazard maps are then combined with exposure and vulnerability information to derive flood risk. Impacts of the forecasted flood events are evaluated in terms of flood prone areas, potential economic damage, and affected population, infrastructures and cities. To further increase the reliability of the proposed methodology we integrated model-based estimations with an innovative methodology for social media monitoring, which allows for real-time verification of impact forecasts. The preliminary tests provided good results and showed the potential of the developed real-time operational procedure in helping emergency response and management. In particular, the link with social media is crucial for improving the accuracy of impact predictions.

A statistical approach to evaluate flood risk at the regional level: an application to Italy

Science.gov (United States)

Rossi, Mauro; Marchesini, Ivan; Salvati, Paola; Donnini, Marco; Guzzetti, Fausto; Sterlacchini, Simone; Zazzeri, Marco; Bonazzi, Alessandro; Carlesi, Andrea

2016-04-01

Floods are frequent and widespread in Italy, causing every year multiple fatalities and extensive damages to public and private structures. A pre-requisite for the development of mitigation schemes, including financial instruments such as insurance, is the ability to quantify their costs starting from the estimation of the underlying flood hazard. However, comprehensive and coherent information on flood prone areas, and estimates on the frequency and intensity of flood events, are not often available at scales appropriate for risk pooling and diversification. In Italy, River Basins Hydrogeological Plans (PAI), prepared by basin administrations, are the basic descriptive, regulatory, technical and operational tools for environmental planning in flood prone areas. Nevertheless, such plans do not cover the entire Italian territory, having significant gaps along the minor hydrographic network and in ungauged basins. Several process-based modelling approaches have been used by different basin administrations for the flood hazard assessment, resulting in an inhomogeneous hazard zonation of the territory. As a result, flood hazard assessments expected and damage estimations across the different Italian basin administrations are not always coherent. To overcome these limitations, we propose a simplified multivariate statistical approach for the regional flood hazard zonation coupled with a flood impact model. This modelling approach has been applied in different Italian basin administrations, allowing a preliminary but coherent and comparable estimation of the flood hazard and the relative impact. Model performances are evaluated comparing the predicted flood prone areas with the corresponding PAI zonation. The proposed approach will provide standardized information (following the EU Floods Directive specifications) on flood risk at a regional level which can in turn be more readily applied to assess flood economic impacts. Furthermore, in the assumption of an appropriate

Flood early warning system in I.R. of Iran

International Nuclear Information System (INIS)

Samadi, Slina; Jamali, Javad B.; Javanmard, Soheila

2004-01-01

At the close of the twentieth century, natural hazards and disasters are one of the most common forms of disasters around the world. Natural disasters cause in significant loss of life and serious economic, environmental and social impacts that greatly retard the development process. Careful hazard assessment and planning, and a range of social, economic and political measures, can significantly contain these threats. Risk is defined as the potential for loss or damage as the result of a particular action or decision and Risk Management is a process consisting of well-defined steps which, when taken in sequence, support better decision making by contributing to a greater insight into risks and their impacts. Most commonly, there are three components in a natural disaster plan: monitoring and early warning; risk assessment; and mitigation and response. Given the improved tools and technologies available today, it is possible to provide disaster information and minimize the potential damage of disasters. In the following parts of the report, the national early warning systems for flood would be discussed, as one of the important component of natural disaster risk management. In 1. R. of Iran, also, different types of natural disasters occur, such as drought, flood, earthquake, sea-level rise, dust storm, hail, freezing and etc, but Flood hazard and disaster is one of the most frequent and damaging types of natural disasters. They have been the most common type of geophysical disaster in the latter half of the twentieth century in Iran, generating an estimated more than 20 percent of all disasters from 1950 to 2003. One of the hazardous floods of Iran occurred in Golestan and north of Khorasan provinces, located in north-east of the country, on August 2001 and 2002. In this regard, according to the responsibility of I. R. of Iran Meteorological Organization (IRIMO) on the flood forecasting, the early warning issue of the mentioned flood, issued within 48 hour's in

External hazards at Kozloduy and Belene NPP sites

International Nuclear Information System (INIS)

Kostov, Marin; Varbanov, Georgy; Andonov, Anton

2011-01-01

Conclusions 1. KNPP and BNPP have adequate seismic design base that corresponds to the current standards 2. There is available seismic margin and cliff-edge effects are not probable 3. The external flooding hazard is properly assessed and there is available design margin 4. Anthropogenic hazards are properly assessed and there is available margin. The BNPP is designed also for the largest available aircraft impact (malevolent) 5. The tornado hazard in Bulgaria is negligible. The extreme combination of EQ, flooding, extreme wind, extreme cold and hot weather have to be studied 7. The risk of failure of all surrounding infrastructure due to earthquake, flooding or anthropogenic actions have to be studied 8. The preparedness for extreme hazards have to be improved and trained 9. The extreme hazard mitigation measures have to be constant and continuous effort

Loss of life in flood events

Science.gov (United States)

Špitalar, Maruša

2013-04-01

Natural disasters per se give a negative connotation. They are destructive to material elements in a space, nature itself and represent a threat to peoples' lives and health. Floods, especially flash floods due to its power and happening suddenly cause extensive damage. Hence, they are hard to predict and are characterized with violent movement, lots of lives are lost. Floods are among natural hazards the one causing the highest number of fatalities. Having said that very important aspects are humans' vulnerability, risk perception, their behavior when confronted with hazardous situations and on the other hand issues related to adequate warning signs and canals of communication. It is very important to take into consideration this segments also and not mainly just structural measures. However the aim of this paper is to emphasis mainly the social aspects of floods. It consists of two main parts. First one refers to mans' vulnerability, risk perception when it comes to danger caused by rising waters and how does culture influences peoples' response and reaction to flood causalities. The second part consists of data about detailed information on circumstances of death that have been collected from several different sources from several EU countries. There has been also available information on the age and gender of people who lost lives in flood events. With gender males dominated among death people since tend to risk more in risky situations. There has been also defined a vulnerable age group among flood fatalities. Analysis of circumstance of death enabled us to define risky groups that are very important for flood managers. Further on this is very beneficial also for risk prevention, early warning systems and creating the best canals in order to information about upcoming danger would successfully reach people at hazardous areas and also for the others to avoid them.

Comparison of 2D numerical models for river flood hazard assessment: simulation of the Secchia River flood in January, 2014

Science.gov (United States)

Shustikova, Iuliia; Domeneghetti, Alessio; Neal, Jeffrey; Bates, Paul; Castellarin, Attilio

2017-04-01

that would be efficient for simulating flooding scenarios for large and very large floodplains. This research aims at contributing to the reduction of uncertainties and limitations in hazard and risk assessment.

Impact of modelling scale on probabilistic flood risk assessment: the Malawi case

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Rudari Roberto

2016-01-01

Full Text Available In the early months of 2015, destructive floods hit Malawi, causing deaths and economic losses. Flood risk assessment outcomes can be used to increase scientific-supported awareness of risk. The recent increase in availability of high resolution data such as TanDEM-X at 12m resolution makes possible the use of detailed physical based flood hazard models in risk assessment. Nonetheless the scale of hazard modelling still remains an issue, which requires a compromise between level of detail and computational efforts. This work presents two different approaches on hazard modelling. Both methods rely on 32-years of numeric weather re-analysis and rainfall-runoff transformation through a fully distributed WFLOW-type hydrological model. The first method, applied at national scale, uses fast post-processing routines, which estimate flood water depth at a resolution of about 1×1km. The second method applies a full 2D hydraulic model to propagate water discharge into the flood plains and best suites for small areas where assets are concentrated. At the 12m resolution, three hot spots with a model area of approximately 10×10 km are analysed. Flood hazard maps obtained with both approaches are combined with flood impact models at the same resolution to generate indicators for flood risk. A quantitative comparison of the two approaches is presented in order to show the effects of modelling scale on both hazard and impact losses.

Social vulnerability in the flood-prone anthropogenic landscape of Northern Italy

Science.gov (United States)

Roder, Giulia; Sofia, Giulia; Wu, Zhifeng; Tarolli, Paolo

2017-04-01

The practices for reducing the impacts of floods are becoming more and more advanced, centred to the communities and reached out to vulnerable populations. Vulnerable individuals are characterised by different social and economic attributes that can alter their capacity to cope with disaster events. The Social Vulnerability Index (Cutter et al. 2003) provides an empirical basis to compare social variances in different spatial scenarios and environmental threats. This methodology has been readjusted to the flood-prone anthropogenic landscape of Northern Italy adapted to the societal and historical construction of this area. In fact, the fifteen census variables used have been contextualised by examining the economic crisis, the modification of the labour force, the gendered life expectancy, the immigration among much more. At a general consideration, the unstable economic status, the population growth, age, and ethnicity are the major social attributes affecting the residents of the floodplain. The cluster analysis performed by the calculation of univariate LISA ratifies the spatial distribution of the index (Moran's I of 0.39 showing a positive correlation) finding the main high-high clusters in the Western and the outlet of the Po River basin. This basin includes one-third of the Italian population and this anthropogenic footprint has consistently modified the basin natural and geological environment (Carminati and Martinelli 2002) to the point that the hydraulic system will be dramatically altered in the future (Dankers and Feyen 2008). The spatial identification and the inclusion of vulnerable people into the risk management planning process have been widely discussed in the Sendai Framework for Disaster Risk Reduction. For this reason, we analysed the flood risk resulting from the combination of high vulnerable areas with the highest flood hazard scenario. The hazard map, finalised in May 2015, has been provided by ISPRA Institute with a three-class flood

Composite Flood Risk for Virgin Island

Science.gov (United States)

The Composite Flood Risk layer combines flood hazard datasets from Federal Emergency Management Agency (FEMA) flood zones, NOAA's Shallow Coastal Flooding, and the National Hurricane Center SLOSH model for Storm Surge inundation for category 1, 2, and 3 hurricanes.Geographic areas are represented by a grid of 10 by 10 meter cells and each cell has a ranking based on variation in exposure to flooding hazards: Moderate, High and Extreme exposure. Geographic areas in each input layers are ranked based on their probability of flood risk exposure. The logic was such that areas exposed to flooding on a more frequent basis were given a higher ranking. Thus the ranking incorporates the probability of the area being flooded. For example, even though a Category 3 storm surge has higher flooding elevations, the likelihood of the occurrence is lower than a Category 1 storm surge and therefore the Category 3 flood area is given a lower exposure ranking. Extreme exposure areas are those areas that are exposed to relatively frequent flooding.The ranked input layers are then converted to a raster for the creation of the composite risk layer by using cell statistics in spatial analysis. The highest exposure ranking for a given cell in any of the three input layers is assigned to the corresponding cell in the composite layer.For example, if an area (a cell) is rank as medium in the FEMA layer, moderate in the SLOSH layer, but extreme in the SCF layer, the cell will be considere

Coastal flood protection management under uncertainty – the Danish case

DEFF Research Database (Denmark)

Jumppanen Andersen, Kaija; Sørensen, Carlo Sass; Piontkowitz, Thorsten

Local stakeholders responsible for coastal management. In Denmark, the responsibility of defining, planning and implementing coastal flood protection lies with the local stakeholders, such as landowners and municipalities. Similarly, it is a municipal responsibility to define building foundation...... and flood protection levels in urban planning and long term development. These planning and protection levels are most often defined from the hazard instead of a risk perspective.The Danish Coastal Authority (DCA) guides local stakeholders on general coastal flood protection and implements the EU Flood...... Directive on flood risk reduction in appointed areas of significant flood risk. DCA is obligated to communicate the concept of risk and, in a thorough and easily comprehendible way, the hazards and uncertainties relating to this today and in the future....

Probabilistic Flood Maps to support decision-making: Mapping the Value of Information

Science.gov (United States)

Alfonso, L.; Mukolwe, M. M.; Di Baldassarre, G.

2016-02-01

Floods are one of the most frequent and disruptive natural hazards that affect man. Annually, significant flood damage is documented worldwide. Flood mapping is a common preimpact flood hazard mitigation measure, for which advanced methods and tools (such as flood inundation models) are used to estimate potential flood extent maps that are used in spatial planning. However, these tools are affected, largely to an unknown degree, by both epistemic and aleatory uncertainty. Over the past few years, advances in uncertainty analysis with respect to flood inundation modeling show that it is appropriate to adopt Probabilistic Flood Maps (PFM) to account for uncertainty. However, the following question arises; how can probabilistic flood hazard information be incorporated into spatial planning? Thus, a consistent framework to incorporate PFMs into the decision-making is required. In this paper, a novel methodology based on Decision-Making under Uncertainty theories, in particular Value of Information (VOI) is proposed. Specifically, the methodology entails the use of a PFM to generate a VOI map, which highlights floodplain locations where additional information is valuable with respect to available floodplain management actions and their potential consequences. The methodology is illustrated with a simplified example and also applied to a real case study in the South of France, where a VOI map is analyzed on the basis of historical land use change decisions over a period of 26 years. Results show that uncertain flood hazard information encapsulated in PFMs can aid decision-making in floodplain planning.

Clusters of community exposure to coastal flooding hazards based on storm and sea level rise scenarios—implications for adaptation networks in the San Francisco Bay region

Science.gov (United States)

Hummel, Michelle; Wood, Nathan J.; Schweikert, Amy; Stacey, Mark T.; Jones, Jeanne; Barnard, Patrick L.; Erikson, Li H.

2018-01-01

Sea level is projected to rise over the coming decades, further increasing the extent of flooding hazards in coastal communities. Efforts to address potential impacts from climate-driven coastal hazards have called for collaboration among communities to strengthen the application of best practices. However, communities currently lack practical tools for identifying potential partner communities based on similar hazard exposure characteristics. This study uses statistical cluster analysis to identify similarities in community exposure to flooding hazards for a suite of sea level rise and storm scenarios. We demonstrate this approach using 63 jurisdictions in the San Francisco Bay region of California (USA) and compare 21 distinct exposure variables related to residents, employees, and structures for six hazard scenario combinations of sea level rise and storms. Results indicate that cluster analysis can provide an effective mechanism for identifying community groupings. Cluster compositions changed based on the selected societal variables and sea level rise scenarios, suggesting that a community could participate in multiple networks to target specific issues or policy interventions. The proposed clustering approach can serve as a data-driven foundation to help communities identify other communities with similar adaptation challenges and to enhance regional efforts that aim to facilitate adaptation planning and investment prioritization.

Social attitudes towards floods in Poland - spatial differentiation

Science.gov (United States)

Biernacki, W.; Działek, J.; Bokwa, A.

2012-04-01

Our paper discusses results of research conducted in Southern Poland focusing on social attitudes towards floods - natural hazards frequently observed in Poland. Lately (e.g. 1997, 2001, 2010) several hundred thousand of people suffered from floods occurring in all examined communities. Presented analyses are based on questionnaire survey in which several criteria were used to select places for studies: objective degree of risk, prior experience of extreme events, size of community, strength of social bonds, social capital and quality of life. Nearly 2000 responses (from 9 communities) were gathered from the survey. Our main research questions were following: - are there differences between attitudes in those communities depending on how frequently they have experienced floods? - does settlement size have an impact on social attitudes towards floods, especially on mitigation behaviour? - are urban inhabitants less adapted to floods be upheld and do rural communities show more activity in the face of natural disasters? - what do information and education policies concerning floods look like? Three dimensions of social attitudes towards natural hazards were analyzed: cognitive (knowledge and awareness of local hazards), emotional (feelings towards hazards, like concern and anxiety); and instrumental (actions taken in response to a potential natural disaster). A combination of these three dimensions produces various types of perception and behaviour towards the perceived hazard (Raaijmakers et al., 2008): ignorance when the local population is unaware of a threat and therefore develops no concern and takes no preventive actions; safety when the local population is aware of a threat, but regards its level as either low or acceptable and is therefore not concerned with the threat and makes no preparations for a disaster; risk reduction when a high level of awareness and concern produces the mechanism of reducing the cognitive dissonance and denial of a disaster threat

Use of Space Technology in Flood Mitigation (Western Province, Zambia)

Science.gov (United States)

Mulando, A.

2001-05-01

Disasters, by definition are events that appear suddenly and with little warning. They are usually short lived, with extreme events bringing death, injury and destruction of buildings and communications. Their aftermath can be as damaging as their physical effects through destruction of sanitation and water supplies, destruction of housing and breakdown of transport for food, temporary shelter and emergency services. Since floods are one of the natural disasters which endanger both life and property, it becomes vital to know its extents and where the hazards exists. Flood disasters manifest natural processes on a larger scale and information provided by Remote Sensing is a most appropriate input to analysis of actual events and investigations of potential risks. An analytical and qualitative image processing and interpretation of Remotely Sensed data as well as other data such as rainfall, population, settlements not to mention but a few should be used to derive good mitigation strategies. Since mitigation is the cornerstone of emergency management, it therefore becomes a sustained action that will reduce or eliminate long term risks to people and property from natural hazards such as floods and their effects. This will definitely involve keeping of homes and other sensitive structures away from flood plains. Promotion of sound land use planning based on this known hazard, "FLOODS" is one such form of mitigation that can be applied in flood affected areas within flood plain. Therefore future mitigation technologies and procedures should increasingly be based on the use of flood extent information provided by Remote Sensing Satellites like the NOAA AVHRR as well as information on the designated flood hazard and risk areas.

Challenges of torrential flood risk management in Serbia

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Petrović Ana M.

2015-01-01

Full Text Available Torrential floods are the natural hydrological hazards manifesting as a consequence of extreme rainfall episodes which have a quick response from the watersheds of small areas, steep slopes and intensive soil erosion. Taking in consideration the nature of torrential flood (sudden and destructive occurrence and the fact they are the most frequent natural hazards in Serbia, torrential flood risk management is a real challenge. Instead of partial solutions for flood protection, integrated torrential flood risk management is more meaningful and effective. The key steps should be an improvement of the legal framework on national level and an expansion of technical and biological torrent control works in river basins. Consequences for society can be significantly reduced if there is an efficient forecast and timely warning, rescue and evacuation and if affected population is educated about flood risks and measures which can be undertaken in case of emergency situation. In this paper, all aspects of torrential flood risk management are analyzed. [Projekat Ministarstva nauke Republike Srbije, br. 47007 III

Climate change track in river floods in Europe

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Z. W. Kundzewicz

2015-06-01

Full Text Available A holistic perspective on changing river flood risk in Europe is provided. Economic losses from floods have increased, principally driven by the expanding exposure of assets at risk. Climate change (i.e. observed increase in precipitation intensity, decrease of snowpack and other observed climate changes might already have had an impact on floods. However, no gauge-based evidence had been found for a climate-driven, widespread change in the magnitude/frequency of floods during the last decades. There are strong regional and sub-regional variations in the trends. Moreover, it has not been generally possible to attribute rain-generated peak streamflow trends to anthropogenic climate change. Physical reasoning suggests that projected increases in the frequency and intensity of heavy rainfall would contribute to increases in rain-generated local floods, while less snowmelt flooding and earlier spring peak flows in snowmelt-fed rivers are expected. However, there is low confidence in future changes in flood magnitude and frequency resulting from climate change. The impacts of climate change on flood characteristics are highly sensitive to the detailed nature of those changes. Discussion of projections of flood hazard in Europe is offered. Attention is drawn to a considerable uncertainty - over the last decade or so, projections of flood hazard in Europe have largely changed.

Elk River Watershed - Flood Study

Science.gov (United States)

Barnes, C. C.; Byrne, J. M.; MacDonald, R. J.; Lewis, D.

2014-12-01

Flooding has the potential to cause significant impacts to economic activities as well as to disrupt or displace populations. Changing climate regimes such as extreme precipitation events increase flood vulnerability and put additional stresses on infrastructure. Potential flooding from just under 100 (2009 NPRI Reviewed Facility Data Release, Environment Canada) toxic tailings ponds located in Canada increase risk to human safety and the environment. One such geotechnical failure spilt billions of litres of toxic tailings into the Fraser River watershed, British Columbia, when a tailings pond dam breach occurred in August 2014. Damaged and washed out roadways cut access to essential services as seen by the extensive floods that occurred in Saskatchewan and Manitoba in July 2014, and in Southern Alberta in 2013. Recovery efforts from events such as these can be lengthy, and have substantial social and economic impacts both in loss of revenue and cost of repair. The objective of this study is to investigate existing conditions in the Elk River watershed and model potential future hydrological changes that can increase flood risk hazards. By analyzing existing hydrology, meteorology, land cover, land use, economic, and settlement patterns a baseline is established for existing conditions in the Elk River watershed. Coupling the Generate Earth Systems Science (GENESYS) high-resolution spatial hydrometeorological model with flood hazard analysis methodology, high-resolution flood vulnerability base line maps are created using historical climate conditions. Further work in 2015 will examine possible impacts for a range of climate change and land use change scenarios to define changes to future flood risk and vulnerability.

Dynamic building risk assessment theoretic model for rainstorm-flood utilization ABM and ABS

Science.gov (United States)

Lai, Wenze; Li, Wenbo; Wang, Hailei; Huang, Yingliang; Wu, Xuelian; Sun, Bingyun

2015-12-01

Flood is one of natural disasters with the worst loss in the world. It needs to assess flood disaster risk so that we can reduce the loss of flood disaster. Disaster management practical work needs the dynamic risk results of building. Rainstorm flood disaster system is a typical complex system. From the view of complex system theory, flood disaster risk is the interaction result of hazard effect objects, rainstorm flood hazard factors, and hazard environments. Agent-based modeling (ABM) is an important tool for complex system modeling. Rainstorm-flood building risk dynamic assessment method (RFBRDAM) was proposed using ABM in this paper. The interior structures and procedures of different agents in proposed meth had been designed. On the Netlogo platform, the proposed method was implemented to assess the building risk changes of the rainstorm flood disaster in the Huaihe River Basin using Agent-based simulation (ABS). The results indicated that the proposed method can dynamically assess building risk of the whole process for the rainstorm flood disaster. The results of this paper can provide one new approach for flood disaster building risk dynamic assessment and flood disaster management.

Effects of Flood Control Strategies on Flood Resilience Under Sociohydrological Disturbances

Science.gov (United States)

Sung, Kyungmin; Jeong, Hanseok; Sangwan, Nikhil; Yu, David J.

2018-04-01

A community capacity to cope with flood hazards, or community flood resilience, emerges from the interplay of hydrological and social processes. This interplay can be significantly influenced by the flood control strategy adopted by a society, i.e., how a society sets its desired flood protection level and strives to achieve this goal. And this interplay can be further complicated by rising land-sea level differences, seasonal water level fluctuations, and economic change. But not much research has been done on how various forms of flood control strategies affect human-flood interactions under these disturbances and therefore flood resilience in the long run. The current study is an effort to address these issues by developing a conceptual model of human-flood interaction mediated by flood control strategies. Our model extends the existing model of Yu et al. (2017), who investigated the flood resilience of a community-based flood protection system in coastal Bangladesh. The major extensions made in this study are inclusions of various forms of flood control strategies (both adaptive and nonadaptive ones), the challenge of rising land-sea level differences, and various high tide level scenarios generated from modifying the statistical variances and averages. Our results show that adaptive forms of flood control strategies tend to outperform nonadaptive ones for maintaining the model community's flood protection system. Adaptive strategies that dynamically adjust target flood protection levels through close monitoring of flood damages and social memories of flood risk can help the model community deal with various disturbances.

Spatiotemporal aspects of flood exposure in Switzerland

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Röthlisberger Veronika

2016-01-01

Full Text Available While flood hazard mapping in Switzerland is close to completion, only a limited number of studies have been specifically conducted on exposure and vulnerability. We fill this knowledge gap by conducting a nation-wide study of flood exposure of buildings in Switzerland. Therefore, we generate a country-wide comprehensive and homogenous data set of polygons of residential buildings and their period of construction and overlay these building polygons with compiled and harmonized flood hazard maps provided by the Swiss cantons. In this paper we present first results of spatiotemporal analyses, namely the evolution of exposure from 1919 to 2012. Surprising is the increase in the share of exposure of new constructed buildings since the 1980s which contradicts the indented effects of the Swiss flood risk management strategies and calls for further investigations.

Vacating the Floodplain: Urban Property, Engineering, and Floods in Brisbane (1974-2011

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Margaret Cook

2017-01-01

Full Text Available This article exposes the dominant socio-economic and political values that shaped flood management between 1974 and 2011 in Brisbane, Queensland, Australia. By the 1970s, international hazard scholarship advocated regulating land use as an effective flood mitigation tool. In 1974, floods devastated Southeast Queensland and highlighted the hazards of building on floodplains. Drawing on scholarship that frames floods as a cultural, rather than natural event, this paper shows that the state government of Queensland prioritised property development and continued to rely on dam building as a way of controlling floods. Dams were built with the aim of providing immunity from flooding, but tensions between State and local governments allowed both to evade responsibility for the growing hazard arising from continuing development in the floodplain. When legislation and regulations were introduced to control floodplain development, they reflected popular sentiment against land use restrictions and hence were limited in scope, non-mandatory, and riddled with loopholes. The results of these inadequate land use regulations and continued residential development below the 100-year flood level were fully exposed in 2011 when a substantial increase in damages accompanied flooding of the Brisbane River. Despite evidence and predictions of increased risk of more frequent and larger floods from a warming climate, both state and local governments have continued to promote development in the Brisbane River floodplain, and appear willing to subject the city and its residents to increased hazards and vulnerability.

A Cascading Storm-Flood-Landslide Guidance System: Development and Application in China

Science.gov (United States)

Zeng, Ziyue; Tang, Guoqiang; Long, Di; Ma, Meihong; Hong, Yang

2016-04-01

Flash floods and landslides, triggered by storms, often interact and cause cascading effects on human lives and property. Satellite remote sensing data has significant potential use in analysis of these natural hazards. As one of the regions continuously affected by severe flash floods and landslides, Yunnan Province, located in Southwest China, has a complex mountainous hydrometeorology and suffers from frequent heavy rainfalls from May through to late September. Taking Yunnan as a test-bed, this study proposed a Cascading Storm-Flood-Landslide Guidance System to progressively analysis and evaluate the risk of the multi-hazards based on multisource satellite remote sensing data. First, three standardized rainfall amounts (average daily amount in flood seasons, maximum 1h and maximum 6h amount) from the products of Topical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) were used as rainfall indicators to derive the StorM Hazard Index (SMHI). In this process, an integrated approach of the Analytic Hierarchy Process (AHP) and the Information-Entropy theory was adopted to determine the weight of each indicator. Then, land cover and vegetation cover data from the Moderate Resolution Imaging Spectroradiometer (MODIS) products, soil type from the Harmonized World Soil Database (HWSD) soil map, and slope from the Shuttle Radar Topography Mission (SRTM) data were add as semi-static geo-topographical indicators to derive the Flash Flood Hazard Index (FFHI). Furthermore, three more relevant landslide-controlling indicators, including elevation, slope angle and soil text were involved to derive the LandSlide Hazard Index (LSHI). Further inclusion of GDP, population and prevention measures as vulnerability indicators enabled to consecutively predict the risk of storm to flash flood and landslide, respectively. Consequently, the spatial patterns of the hazard indices show that the southeast of Yunnan has more possibility to encounter with storms

Large Scale Flood Risk Analysis using a New Hyper-resolution Population Dataset

Science.gov (United States)

Smith, A.; Neal, J. C.; Bates, P. D.; Quinn, N.; Wing, O.

2017-12-01

Here we present the first national scale flood risk analyses, using high resolution Facebook Connectivity Lab population data and data from a hyper resolution flood hazard model. In recent years the field of large scale hydraulic modelling has been transformed by new remotely sensed datasets, improved process representation, highly efficient flow algorithms and increases in computational power. These developments have allowed flood risk analysis to be undertaken in previously unmodeled territories and from continental to global scales. Flood risk analyses are typically conducted via the integration of modelled water depths with an exposure dataset. Over large scales and in data poor areas, these exposure data typically take the form of a gridded population dataset, estimating population density using remotely sensed data and/or locally available census data. The local nature of flooding dictates that for robust flood risk analysis to be undertaken both hazard and exposure data should sufficiently resolve local scale features. Global flood frameworks are enabling flood hazard data to produced at 90m resolution, resulting in a mis-match with available population datasets which are typically more coarsely resolved. Moreover, these exposure data are typically focused on urban areas and struggle to represent rural populations. In this study we integrate a new population dataset with a global flood hazard model. The population dataset was produced by the Connectivity Lab at Facebook, providing gridded population data at 5m resolution, representing a resolution increase over previous countrywide data sets of multiple orders of magnitude. Flood risk analysis undertaken over a number of developing countries are presented, along with a comparison of flood risk analyses undertaken using pre-existing population datasets.

Flood Hazard Zonation by Combining Mod-Clark and HEC-RAS Models in Bustan Dam Basin, Golestan Province

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Z. Parisay

2014-12-01

Full Text Available Flood is one of the devastating phenomena which every year incurs casualties and property damages. Flood zonation is an efficient technique for flood management. The main goal of this research is flood hazard and risk zonation along a 21 km reach of the Gorganrud river in Bustan dam watershed considering two conditions: present landuse condition and scenario planning. To this end a combination of a hydrologic model (the distributed HEC-HMS with the Mod-Clark transform option and a hydraulic model (HEC-RAS were used. The required inputs to run the Mod-Clarck module of HEC-HMS are gridded files of river basin, curve number and rainfall with the SHG coordinate system and DSS format. In this research the input files were prepared using the Watershed Modeling System (WMS at cell size of 200 m. Since the Mod-Clark method requires rainfall data as radar format (NEXRAD, the distributed rainfall mapseries with time intervals of 15 minutes prepared within the PCRaster GIS system were converted to the DSS format using the asc2dss package. also the curve number map was converted to the DSS format using HEC-GeoHMS. Then, these DSS files were substituted with rainfall and curve number maps within the WMS. After calibration and validation, model was run for return periods of 2, 5, 10, 25, 50, 100 and 200 years, in two conditions of current landuse and scenario planning. The simulated peak discharge data, geometric parameters of river and cross section (at 316 locations data prepared by the HEC-GeoRAS software and roughness coefficients data, were used by the HEC-RAS software to simulate the hydraulic behavior of the river and flood inundation area maps were produced using GIS. The results of the evaluation showed that in addition to the percent error in peak flow, less than 3.2%, the model has a good performance in peak flow simulation, but is not successful in volume estimation. The results of flood zones revealed that from the total area in floodplain with

Societal transformation and adaptation necessary to manage dynamics in flood hazard and risk mitigation (TRANS-ADAPT)

Science.gov (United States)

Fuchs, Sven; Thaler, Thomas; Bonnefond, Mathieu; Clarke, Darren; Driessen, Peter; Hegger, Dries; Gatien-Tournat, Amandine; Gralepois, Mathilde; Fournier, Marie; Mees, Heleen; Murphy, Conor; Servain-Courant, Sylvie

2015-04-01

Facing the challenges of climate change, this project aims to analyse and to evaluate the multiple use of flood alleviation schemes with respect to social transformation in communities exposed to flood hazards in Europe. The overall goals are: (1) the identification of indicators and parameters necessary for strategies to increase societal resilience, (2) an analysis of the institutional settings needed for societal transformation, and (3) perspectives of changing divisions of responsibilities between public and private actors necessary to arrive at more resilient societies. This proposal assesses societal transformations from the perspective of changing divisions of responsibilities between public and private actors necessary to arrive at more resilient societies. Yet each risk mitigation measure is built on a narrative of exchanges and relations between people and therefore may condition the outputs. As such, governance is done by people interacting and defining risk mitigation measures as well as climate change adaptation are therefore simultaneously both outcomes of, and productive to, public and private responsibilities. Building off current knowledge this project will focus on different dimensions of adaptation and mitigation strategies based on social, economic and institutional incentives and settings, centring on the linkages between these different dimensions and complementing existing flood risk governance arrangements. The policy dimension of adaptation, predominantly decisions on the societal admissible level of vulnerability and risk, will be evaluated by a human-environment interaction approach using multiple methods and the assessment of social capacities of stakeholders across scales. As such, the challenges of adaptation to flood risk will be tackled by converting scientific frameworks into practical assessment and policy advice. In addressing the relationship between these dimensions of adaptation on different temporal and spatial scales, this

Flood Risk, Flood Mitigation, and Location Choice: Evaluating the National Flood Insurance Program's Community Rating System.

Science.gov (United States)

Fan, Qin; Davlasheridze, Meri

2016-06-01

Climate change is expected to worsen the negative effects of natural disasters like floods. The negative impacts, however, can be mitigated by individuals' adjustments through migration and relocation behaviors. Previous literature has identified flood risk as one significant driver in relocation decisions, but no prior study examines the effect of the National Flood Insurance Program's voluntary program-the Community Rating System (CRS)-on residential location choice. This article fills this gap and tests the hypothesis that flood risk and the CRS-creditable flood control activities affect residential location choices. We employ a two-stage sorting model to empirically estimate the effects. In the first stage, individuals' risk perception and preference heterogeneity for the CRS activities are considered, while mean effects of flood risk and the CRS activities are estimated in the second stage. We then estimate heterogeneous marginal willingness to pay (WTP) for the CRS activities by category. Results show that age, ethnicity and race, educational attainment, and prior exposure to risk explain risk perception. We find significant values for the CRS-creditable mitigation activities, which provides empirical evidence for the benefits associated with the program. The marginal WTP for an additional credit point earned for public information activities, including hazard disclosure, is found to be the highest. Results also suggest that water amenities dominate flood risk. Thus, high amenity values may increase exposure to flood risk, and flood mitigation projects should be strategized in coastal regions accordingly. © 2015 Society for Risk Analysis.

Multi-Hazard Interactions in Guatemala

Science.gov (United States)

Gill, Joel; Malamud, Bruce D.

2017-04-01

In this paper, we combine physical and social science approaches to develop a multi-scale regional framework for natural hazard interactions in Guatemala. The identification and characterisation of natural hazard interactions is an important input for comprehensive multi-hazard approaches to disaster risk reduction at a regional level. We use five transdisciplinary evidence sources to organise and populate our framework: (i) internationally-accessible literature; (ii) civil protection bulletins; (iii) field observations; (iv) stakeholder interviews (hazard and civil protection professionals); and (v) stakeholder workshop results. These five evidence sources are synthesised to determine an appropriate natural hazard classification scheme for Guatemala (6 hazard groups, 19 hazard types, and 37 hazard sub-types). For a national spatial extent (Guatemala), we construct and populate a "21×21" hazard interaction matrix, identifying 49 possible interactions between 21 hazard types. For a sub-national spatial extent (Southern Highlands, Guatemala), we construct and populate a "33×33" hazard interaction matrix, identifying 112 possible interactions between 33 hazard sub-types. Evidence sources are also used to constrain anthropogenic processes that could trigger natural hazards in Guatemala, and characterise possible networks of natural hazard interactions (cascades). The outcomes of this approach are among the most comprehensive interaction frameworks for national and sub-national spatial scales in the published literature. These can be used to support disaster risk reduction and civil protection professionals in better understanding natural hazards and potential disasters at a regional scale.

Automating Flood Hazard Mapping Methods for Near Real-time Storm Surge Inundation and Vulnerability Assessment

Science.gov (United States)

Weigel, A. M.; Griffin, R.; Gallagher, D.

2015-12-01

Storm surge has enough destructive power to damage buildings and infrastructure, erode beaches, and threaten human life across large geographic areas, hence posing the greatest threat of all the hurricane hazards. The United States Gulf of Mexico has proven vulnerable to hurricanes as it has been hit by some of the most destructive hurricanes on record. With projected rises in sea level and increases in hurricane activity, there is a need to better understand the associated risks for disaster mitigation, preparedness, and response. GIS has become a critical tool in enhancing disaster planning, risk assessment, and emergency response by communicating spatial information through a multi-layer approach. However, there is a need for a near real-time method of identifying areas with a high risk of being impacted by storm surge. Research was conducted alongside Baron, a private industry weather enterprise, to facilitate automated modeling and visualization of storm surge inundation and vulnerability on a near real-time basis. This research successfully automated current flood hazard mapping techniques using a GIS framework written in a Python programming environment, and displayed resulting data through an Application Program Interface (API). Data used for this methodology included high resolution topography, NOAA Probabilistic Surge model outputs parsed from Rich Site Summary (RSS) feeds, and the NOAA Census tract level Social Vulnerability Index (SoVI). The development process required extensive data processing and management to provide high resolution visualizations of potential flooding and population vulnerability in a timely manner. The accuracy of the developed methodology was assessed using Hurricane Isaac as a case study, which through a USGS and NOAA partnership, contained ample data for statistical analysis. This research successfully created a fully automated, near real-time method for mapping high resolution storm surge inundation and vulnerability for the

Hot wet spots of Swiss buildings - detecting clusters of flood exposure

Science.gov (United States)

Röthlisberger, Veronika; Zischg, Andreas; Keiler, Margreth

2016-04-01

Where are the hotspots of flood exposure in Switzerland? There is no single answer but rather a wide range of findings depending on the databases and methods used. In principle, the analysis of flood exposure is the overlay of two spatial datasets, one on flood hazard and one on assets, e.g. buildings. The presented study aims to test a new developed approach which is based on public available Swiss data. On the hazard side, these are two different types of flood hazard maps each representing a similar return period beyond the dimensioning of structural protection systems. When it comes to assets we use nationwide harmonized data on building, namely a complete dataset of building polygons to which we assign features as volume, residents and monetary value. For the latter we apply findings of multivariate analyses of insurance data. By overlaying building polygons with the flood hazard map we identify the exposed buildings. We analyse the resulting spatial distribution of flood exposure at different levels of scales (local to regional) using administrative units (e.g. municipalities) but also artificial grids with a corresponding size (e.g. 5 000 m). The presentation focuses on the identification of hotspots highlighting the influence of the applied data and methods, e.g. local scan statistics testing intensities within and without potential clusters or log relative exposure surfaces based on kernel intensity estimates. We find a major difference of identified hotspots between absolute values and normalized values of exposure. Whereas the hotspots of flood exposure in absolute figures mirrors the underlying distribution of buildings, the hotspots of flood exposure ratios show very different pictures. We conclude that findings on flood exposure vary depending on the data and moreover the methods used and therefore need to be communicated carefully and appropriate to different stakeholders who may use the information for decision making on flood risk management.

Structural comparison of hazardous and non-hazardous coals based on gas sorption experiments

Energy Technology Data Exchange (ETDEWEB)

Lakatos, J.; Toth, J. [Research Lab. for Mining Chemistry, Hungarian Academy of Sciences, Miskolc-Egyetemvaros (Hungary); Radnai-Gyoengyoes, Z. [Geopard Ltd., Pecs (Hungary); Bokanyi, L. [Miskolc Univ., Miskolc-Egyetemvaros (Hungary). Dept. of Process Engineering

1997-12-31

Comparison of carbon-dioxide and propane sorption at ambient temperature was used for characterising the difference of the structure of hazardous and non hazardous coals. However, hazardous coals were found more microporous or contain more closed pores than non hazardous ones, this difference couldn`t have been enlarged and attributed to one petrographic component by producing the density fractions. Gas sorption isobars (nitrogen, methane, ethane) are proposed to make a distinction between fine pore structure of coals. (orig.)

Flood Risk Assessment in Urban Areas Based on Spatial Analytics and Social Factors

Directory of Open Access Journals (Sweden)

Costas Armenakis

2017-11-01

Full Text Available Flood maps alone are not sufficient to determine and assess the risks to people, property, infrastructure, and services due to a flood event. Simply put, the risk is almost zero to minimum if the flooded region is “empty” (i.e., unpopulated, has not properties, no industry, no infrastructure, and no socio-economic activity. High spatial resolution Earth Observation (EO data can contribute to the generation and updating of flood risk maps based on several aspects including population, economic development, and critical infrastructure, which can enhance a city’s flood mitigation and preparedness planning. In this case study for the Don River watershed, Toronto, the flood risk is determined and flood risk index maps are generated by implementing a methodology for estimating risk based on the geographic coverage of the flood hazard, vulnerability of people, and the exposure of large building structures to flood water. Specifically, the spatial flood risk index maps have been generated through analytical spatial modeling which takes into account the areas in which a flood hazard is expected to occur, the terrain’s morphological characteristics, socio-economic parameters based on demographic data, and the density of large building complexes. Generated flood risk maps are verified through visual inspection with 3D city flood maps. Findings illustrate that areas of higher flood risk coincide with areas of high flood hazard and social and building exposure vulnerability.

Performance of Models for Flash Flood Warning and Hazard Assessment: The 2015 Kali Gandaki Landslide Dam Breach in Nepal

Directory of Open Access Journals (Sweden)

Jeremy D. Bricker

2017-02-01

Full Text Available The 2015 magnitude 7.8 Gorkha earthquake and its aftershocks weakened mountain slopes in Nepal. Co- and postseismic landsliding and the formation of landslide-dammed lakes along steeply dissected valleys were widespread, among them a landslide that dammed the Kali Gandaki River. Overtopping of the landslide dam resulted in a flash flood downstream, though casualties were prevented because of timely evacuation of low-lying areas. We hindcast the flood using the BREACH physically based dam-break model for upstream hydrograph generation, and compared the resulting maximum flow rate with those resulting from various empirical formulas and a simplified hydrograph based on published observations. Subsequent modeling of downstream flood propagation was compromised by a coarse-resolution digital elevation model with several artifacts. Thus, we used a digital-elevation-model preprocessing technique that combined carving and smoothing to derive topographic data. We then applied the 1-dimensional HEC-RAS model for downstream flood routing, and compared it to the 2-dimensional Delft-FLOW model. Simulations were validated using rectified frames of a video recorded by a resident during the flood in the village of Beni, allowing estimation of maximum flow depth and speed. Results show that hydrological smoothing is necessary when using coarse topographic data (such as SRTM or ASTER, as using raw topography underestimates flow depth and speed and overestimates flood wave arrival lag time. Results also show that the 2-dimensional model produces more accurate results than the 1-dimensional model but the 1-dimensional model generates a more conservative result and can be run in a much shorter time. Therefore, a 2-dimensional model is recommended for hazard assessment and planning, whereas a 1-dimensional model would facilitate real-time warning declaration.

Community Based Flood Modeling in Southern and Baja California to Meet End User Needs for Decision-Making

Science.gov (United States)

Sanders, B. F.

2017-12-01

Flooding of coastal and fluvial systems are the most significant natural hazards facing society, and damages have been escalating for decades globally and in the U.S. Almost all metropolitan areas are exposed to flood risk. The threat from river flooding is especially high in India and China, and coastal cities around the world are threatened by storm surge and rising sea levels. Several trends including rising sea levels, urbanization, deforestation, and rural-to-urban population shifts will increase flood exposure in the future. Flood impacts are escalating despite advances in hazards science and extensive effort to manage risks. The fundamental issue is not that flooding is becoming more severe, even though it is in some places, but rather that societies are become more vulnerable to flood impacts. A critical factor contributing to the escalation of flood impacts is that the most vulnerable sectors of communities are left out of processes to prepare for and respond to flooding. Furthermore, the translation of knowledge about flood hazards and vulnerabilities into actionable information for communities has not been effective. In Southern and Baja California, an interdisciplinary team of researchers has partnered with stakeholders in flood vulnerable communities to co-develop flood hazard information systems designed to meet end-user needs for decision-making. The initiative leveraged the power of advanced, fine-scale hydraulic models of flooding to craft intuitive visualizations of context-sensitive scenarios. This presentation will cover the ways by which the process of flood inundation modeling served as a focal point for knowledge development, as well as the unique visualizations that populate on-line information systems accessible here: http://floodrise.uci.edu/online-flood-hazard-viewers/

Modeling of Flood Risk for the Continental United States

Science.gov (United States)

Lohmann, D.; Li, S.; Katz, B.; Goteti, G.; Kaheil, Y. H.; Vojjala, R.

2011-12-01

The science of catastrophic risk modeling helps people to understand the physical and financial implications of natural catastrophes (hurricanes, flood, earthquakes, etc.), terrorism, and the risks associated with changes in life expectancy. As such it depends on simulation techniques that integrate multiple disciplines such as meteorology, hydrology, structural engineering, statistics, computer science, financial engineering, actuarial science, and more in virtually every field of technology. In this talk we will explain the techniques and underlying assumptions of building the RMS US flood risk model. We especially will pay attention to correlation (spatial and temporal), simulation and uncertainty in each of the various components in the development process. Recent extreme floods (e.g. US Midwest flood 2008, US Northeast flood, 2010) have increased the concern of flood risk. Consequently, there are growing needs to adequately assess the flood risk. The RMS flood hazard model is mainly comprised of three major components. (1) Stochastic precipitation simulation module based on a Monte-Carlo analogue technique, which is capable of producing correlated rainfall events for the continental US. (2) Rainfall-runoff and routing module. A semi-distributed rainfall-runoff model was developed to properly assess the antecedent conditions, determine the saturation area and runoff. The runoff is further routed downstream along the rivers by a routing model. Combined with the precipitation model, it allows us to correlate the streamflow and hence flooding from different rivers, as well as low and high return-periods across the continental US. (3) Flood inundation module. It transforms the discharge (output from the flow routing) into water level, which is further combined with a two-dimensional off-floodplain inundation model to produce comprehensive flood hazard map. The performance of the model is demonstrated by comparing to the observation and published data. Output from

Cities and Sea Level Rise: A Roadmap for Flood Hazard Adaptation

Science.gov (United States)

Horn, D. P.; Cousins, A.

2015-12-01

Coastal cities will face a range of increasingly severe challenges as sea level rises, and adaptation to future flood risk will require more than structural defences. Many cities will not be able to rely solely on engineering structures for protection and will need to develop a suite of policy responses to increase their resilience to impacts of rising sea level. Local governments generally maintain day-to-day responsibility and control over the use of the vast majority of property at risk of flooding, and the tools to promote flood risk adaptation are already within the capacity of most cities. Policy tools available to address other land-use problems can be refashioned and used to adapt to sea level rise. This study reviews approaches for urban adaptation through case studies of cities which have developed flood adaptation strategies that combine structural defences with innovative approaches to living with flood risk. The aim of the overall project is to produce a 'roadmap' to guide practitioners through the process of analysing coastal flood risk in urban areas. Technical knowledge of flood risk reduction measures is complemented with a consideration of the essential impact that local policy has on the treatment of coastal flooding and the constraints and opportunities that result from the specific country or locality characteristics in relation to economic, political, social and environmental priorities, which are likely to dictate the approach to coastal flooding and the actions proposed. Detailed analyses of the adaptation strategies used by Rotterdam (Netherlands), Bristol (UK), and Norfolk (Virginia) are used to draw out a range of good practice elements that promote effective adaptation to sea level rise. These can be grouped into risk reduction, governance issues, and insurance, and can be used to provide examples of how other cities could adopt and implement flood adaptation strategies from a relatively limited starting position. Most cities will

Hydrometeorological Hazards: Monitoring, Forecasting, Risk Assessment, and Socioeconomic Responses

Energy Technology Data Exchange (ETDEWEB)

Wu, Huan [University of Maryland, College Park, MD, USA; NASA Goddard Space Flight Center, Greenbelt, MD, USA; Huang, Maoyi [Pacific Northwest National Laboratory, Richland, WA, USA; Tang, Qiuhong [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China; Kirschbaum, Dalia B. [NASA Goddard Space Flight Center, Greenbelt, MD, USA; Ward, Philip [Vrije Universiteit, Amsterdam, Netherlands

2016-01-01

Hydrometeorological hazards are caused by extreme meteorological and climate events, such as floods, droughts, hurricanes, tornadoes, or landslides. They account for a dominant fraction of natural hazards and occur in all regions of the world, although the frequency and intensity of certain hazards, and society’s vulnerability to them, differs between regions. Severe storms, strong winds, floods and droughts develop at different spatial and temporal scales, but all can become disasters that cause significant infrastructure damage and claim hundreds of thousands of lives annually worldwide. Oftentimes, multiple hazards can occur simultaneously or trigger cascading impacts from one extreme weather event. For example, in addition to causing injuries, deaths and material damage, a tropical storm can also result in flooding and mudslides, which can disrupt water purification and sewage disposal systems, cause overflow of toxic wastes, and increase propagation of mosquito-borne diseases.

French people addressing environmental hazards (Eser 2013)

International Nuclear Information System (INIS)

Pautard, Eric; Moreau, Sylvain; Bottin, Anne; Kraszewski, Marlene; Fretin, David; Carriere, Celine; Bird, Geoffrey

2015-07-01

This publication presents the results of a survey, conducted towards the end of 2013, of 4,700 people resident in metropolitan France and its 'departements d'outre-mer' (DOM - overseas departments). The aim of the survey was to ascertain how French people perceive natural hazards (flooding, earthquakes, climate events, cyclones, etc.) and technological hazards (industrial and nuclear) to which they may be exposed. Questioned as to whether or not they felt exposed to one or several environmental hazards in their place of residence, French people's answers varied somewhat depending on the hazard invoked and place of residence. A strong feeling of exposure was expressed most frequently in the DOM. Respondents in both metropolitan France and DOM think that atmospheric pollution is a significant hazard (56%) but their opinions diverge partially where other hazards are concerned. Natural hazards (earthquakes and flooding) are cited most frequently overseas, whereas technological hazards (industrial and nuclear) are primarily metropolitan concerns. Climate change related hazards are seen as a threat by 56% of overseas respondents and by 42% in the mother country. In general, one-third of French people think that they are exposed to more than two environmental hazards. Unlike the younger members of the population, only one-quarter of respondents of 65 years of age or over felt exposed to three or more hazards. From municipal level databases providing information on exposure to flooding and technological and climate-related hazards, the survey indicates that a large majority of respondents living in these municipalities either do not feel at risk from existing hazards or feel that the risk is low (see figure below). It is in the area of climate-related hazards that awareness of threat seems to be highest in France, and more particularly in the DOM. In the face of the flooding that could affect them, overseas populations are more aware of this natural

Flood Risk Analysis in Denpasar City, Bali, Indonesia

Science.gov (United States)

Kusmiyarti, T. B.; Wiguna, P. P. K.; Ratna Dewi, N. K. R.

2018-02-01

Denpasar city is a Capital City of Bali Province and one of the leading tourist destinations in Indonesia. Denpasar area is relatively flat with high rain fall intensity with the domince of settlement. This makes Denpasar City becomes prone area of flood. The aim of this research is to find out the spatial distribution flood hazard and the risk of population which are affected to the flood hazard. Weighting, scoring and overlaying method were used in this research. Six indicators were used to analyze the flood hazard: landuse, rainfall, type of soil, slope, altitute and drainage density. The vulnerability is analyzed per Desa or Kelurahan (Rustic/Neighborhood) with the indicator of age, education and population density. Risk was calculated by multiplied hazard with vulnerability and divided with coping capacity. In this research, coping capacity is determined by the amount of internal budget for each Desa or Kelurahan for development purpose. Flood risk in Denpasar city is divided into five classes, very low risk, low risk, medium risk, high risk and very high risk. Total population with very high risk reached 202478 people or 13.16% of total population. The total area is 780.7 ha or 16.02% from total settlement in Denpasar city. Total population with high risk reached 202478 people or 13.16% of total population. The total area is 780.7 ha or 16.02% from total settlement in Denpasar city. The number of population with medium risk reached 202478 people or 33.51% of total population which occupied 22.95% of total settlements or 1118.18 ha. The total number of population with low risk reached 79435 people or 13.14% of total population with area of low flood risk is 716.89 ha or 14.71% of total settlements in Denpasar City. Very low flood risk with total population at risk reached 19184 people or 31.74% of total population and occupied 2003.54 areas or 41.12% of total areas of settlements.

Predicting floods with Flickr tags.

Science.gov (United States)

Tkachenko, Nataliya; Jarvis, Stephen; Procter, Rob

2017-01-01

Increasingly, user generated content (UGC) in social media postings and their associated metadata such as time and location stamps are being used to provide useful operational information during natural hazard events such as hurricanes, storms and floods. The main advantage of these new sources of data are twofold. First, in a purely additive sense, they can provide much denser geographical coverage of the hazard as compared to traditional sensor networks. Second, they provide what physical sensors are not able to do: By documenting personal observations and experiences, they directly record the impact of a hazard on the human environment. For this reason interpretation of the content (e.g., hashtags, images, text, emojis, etc) and metadata (e.g., keywords, tags, geolocation) have been a focus of much research into social media analytics. However, as choices of semantic tags in the current methods are usually reduced to the exact name or type of the event (e.g., hashtags '#Sandy' or '#flooding'), the main limitation of such approaches remains their mere nowcasting capacity. In this study we make use of polysemous tags of images posted during several recent flood events and demonstrate how such volunteered geographic data can be used to provide early warning of an event before its outbreak.

Contribution of future urbanisation expansion to flood risk changes

Science.gov (United States)

Bruwier, Martin; Mustafa, Ahmed; Archambeau, Pierre; Erpicum, Sébastien; Pirotton, Michel; Teller, Jacques; Dewals, Benjamin

2016-04-01

The flood risk is expected to increase in the future due to climate change and urban development. Climate change modifies flood hazard and urban development influences exposure and vulnerability to floods. While the influence of climate change on flood risk has been studied widely, the impact of urban development also needs to be considered in a sustainable flood risk management approach. The main goal of this study is the determination of the sensitivity of future flood risk to different urban development scenarios at a relatively short-time horizon in the River Meuse basin in Wallonia (Belgium). From the different scenarios, the expected impact of urban development on flood risk is assessed. Three urban expansion scenarios are developed up to 2030 based on a coupled cellular automata (CA) and agent-based (AB) urban expansion model: (i) business-as-usual, (ii) restrictive and (iii) extreme expansion scenarios. The main factor controlling these scenarios is the future urban land demand. Each urban expansion scenario is developed by considering or not high and/or medium flood hazard zones as a constraint for urban development. To assess the model's performance, it is calibrated for the Meuse River valley (Belgium) to simulate urban expansion between 1990 and 2000. Calibration results are then assessed by comparing the 2000 simulated land-use map and the actual 2000 land-use map. The flood damage estimation for each urban expansion scenario is determined for five flood discharges by overlaying the inundation map resulting from a hydraulic computation and the urban expansion map and by using damage curves and specific prices. The hydraulic model Wolf2D has been extensively validated by comparisons between observations and computational results during flood event .This study focuses only on mobile and immobile prices for urban lands, which are associated to the most severe damages caused by floods along the River Meuse. These findings of this study offers tools to

Flooding Capability for River-based Scenarios

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Prescott, Steven [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ryan, Emerald [Idaho State Univ., Pocatello, ID (United States); Calhoun, Donna [Boise State Univ., ID (United States); Sampath, Ramprasad [Centroid Labs., Los Angeles, CA (United States); Anderson, S. Danielle [Idaho National Lab. (INL), Idaho Falls, ID (United States); Casteneda, Cody [Boise State Univ., ID (United States)

2015-10-01

This report describes the initial investigation into modeling and simulation tools for application of riverine flooding representation as part of the Risk-Informed Safety Margin Characterization (RISMC) Pathway external hazards evaluations. The report provides examples of different flooding conditions and scenarios that could impact river and watershed systems. Both 2D and 3D modeling approaches are described.

Flood damage in Italy: towards an assessment model of reconstruction costs

Science.gov (United States)

Sterlacchini, Simone; Zazzeri, Marco; Genovese, Elisabetta; Modica, Marco; Zoboli, Roberto

2016-04-01

Recent decades in Italy have seen a very rapid expansion of urbanisation in terms of physical assets, while demographics have remained stable. Both the characteristics of Italian soil and anthropic development, along with repeated global climatic stress, have made the country vulnerable to floods, the intensity of which is increasingly alarming. The combination of these trends will contribute to large financial losses due to property damage in the absence of specific mitigation strategies. The present study focuses on the province of Sondrio in Northern Italy (area of about 3,200 km²), which is home to more than 180,000 inhabitants and the population is growing slightly. It is clearly a hot spot for flood exposure, as it is primarily a mountainous area where floods and flash floods hit frequently. The model we use for assessing potential flood damage determines risk scenarios by overlaying flood hazard maps and economic asset data. In Italy, hazard maps are provided by Regional Authorities through the Hydrogeological System Management Plan (PAI) based on EU Flood Directive guidelines. The PAI in the study area includes both the large plain and the secondary river system and considers three hazard scenarios of Low, Medium and High Frequency associated with return periods of 20, 200 and 500 years and related water levels. By an overlay of PAI maps and residential areas, visualized on a GIS, we determine which existing built-up areas are at risk for flood according to each scenario. Then we investigate the value of physical assets potentially affected by floods in terms of market values, using the database of the Italian Property Market Observatory (OMI), and in terms of reconstruction costs, by considering synthetic cost indexes of predominant building types (from census information) and PAI water height. This study illustrates a methodology to assess flood damage in urban settlements and aims to determine general guidelines that can be extended throughout Italy

Hurricane Harvey Riverine Flooding: Part 1 - Reconstruction of Hurricane Harvey Flooding for Harris County, TX using a GPU-accelerated 2D flood model for post-flood hazard analysis

Science.gov (United States)

Kalyanapu, A. J.; Dullo, T. T.; Gangrade, S.; Kao, S. C.; Marshall, R.; Islam, S. R.; Ghafoor, S. K.

2017-12-01

Hurricane Harvey that made landfall in the southern Texas this August is one of the most destructive hurricanes during the 2017 hurricane season. During its active period, many areas in coastal Texas region received more than 40 inches of rain. This downpour caused significant flooding resulting in about 77 casualties, displacing more than 30,000 people, inundating hundreds of thousands homes and is currently estimated to have caused more than $70 billion in direct damage. One of the significantly affected areas is Harris County where the city of Houston, TX is located. Covering over two HUC-8 drainage basins ( 2702 mi2), this county experienced more than 80% of its annual average rainfall during this event. This study presents an effort to reconstruct flooding caused by extreme rainfall due to Hurricane Harvey in Harris County, Texas. This computationally intensive task was performed at a 30-m spatial resolution using a rapid flood model called Flood2D-GPU, a graphics processing unit (GPU) accelerated model, on Oak Ridge National Laboratory's (ORNL) Titan Supercomputer. For this task, the hourly rainfall estimates from the National Center for Environmental Prediction Stage IV Quantitative Precipitation Estimate were fed into the Variable Infiltration Capacity (VIC) hydrologic model and Routing Application for Parallel computation of Discharge (RAPID) routing model to estimate flow hydrographs at 69 locations for Flood2D-GPU simulation. Preliminary results of the simulation including flood inundation extents, maps of flood depths and inundation duration will be presented. Future efforts will focus on calibrating and validating the simulation results and assessing the flood damage for better understanding the impacts made by Hurricane Harvey.

Flood maps in Europe - methods, availability and use

Science.gov (United States)

de Moel, H.; van Alphen, J.; Aerts, J. C. J. H.

2009-03-01

To support the transition from traditional flood defence strategies to a flood risk management approach at the basin scale in Europe, the EU has adopted a new Directive (2007/60/EC) at the end of 2007. One of the major tasks which member states must carry out in order to comply with this Directive is to map flood hazards and risks in their territory, which will form the basis of future flood risk management plans. This paper gives an overview of existing flood mapping practices in 29 countries in Europe and shows what maps are already available and how such maps are used. Roughly half of the countries considered have maps covering as good as their entire territory, and another third have maps covering significant parts of their territory. Only five countries have very limited or no flood maps available yet. Of the different flood maps distinguished, it appears that flood extent maps are the most commonly produced floods maps (in 23 countries), but flood depth maps are also regularly created (in seven countries). Very few countries have developed flood risk maps that include information on the consequences of flooding. The available flood maps are mostly developed by governmental organizations and primarily used for emergency planning, spatial planning, and awareness raising. In spatial planning, flood zones delimited on flood maps mainly serve as guidelines and are not binding. Even in the few countries (e.g. France, Poland) where there is a legal basis to regulate floodplain developments using flood zones, practical problems are often faced which reduce the mitigating effect of such binding legislation. Flood maps, also mainly extent maps, are also created by the insurance industry in Europe and used to determine insurability, differentiate premiums, or to assess long-term financial solvency. Finally, flood maps are also produced by international river commissions. With respect to the EU Flood Directive, many countries already have a good starting point to map

An Agent-Based Model of Evolving Community Flood Risk.

Science.gov (United States)

Tonn, Gina L; Guikema, Seth D

2017-11-17

Although individual behavior plays a major role in community flood risk, traditional flood risk models generally do not capture information on how community policies and individual decisions impact the evolution of flood risk over time. The purpose of this study is to improve the understanding of the temporal aspects of flood risk through a combined analysis of the behavioral, engineering, and physical hazard aspects of flood risk. Additionally, the study aims to develop a new modeling approach for integrating behavior, policy, flood hazards, and engineering interventions. An agent-based model (ABM) is used to analyze the influence of flood protection measures, individual behavior, and the occurrence of floods and near-miss flood events on community flood risk. The ABM focuses on the following decisions and behaviors: dissemination of flood management information, installation of community flood protection, elevation of household mechanical equipment, and elevation of homes. The approach is place based, with a case study area in Fargo, North Dakota, but is focused on generalizable insights. Generally, community mitigation results in reduced future damage, and individual action, including mitigation and movement into and out of high-risk areas, can have a significant influence on community flood risk. The results of this study provide useful insights into the interplay between individual and community actions and how it affects the evolution of flood risk. This study lends insight into priorities for future work, including the development of more in-depth behavioral and decision rules at the individual and community level. © 2017 Society for Risk Analysis.

Emotional engagement with participatory simulations as a tool for learning and decision-support for coupled human-natural systems: Flood hazards and urban development

Science.gov (United States)

Gilligan, J. M.; Corey, B.; Camp, J. V.; John, N. J.; Sengupta, P.

2015-12-01

The complex interactions between land use and natural hazards pose serious challenges in education, research, and public policy. Where complex nonlinear interactions produce unintuitive results, interactive computer simulations can be useful tools for education and decision support. Emotions play important roles in cognition and learning, especially where risks are concerned. Interactive simulations have the potential to harness emotional engagement to enhance learning and understanding of risks in coupled human-natural systems. We developed a participatory agent-based simulation of cities at risk of river flooding. Participants play the role of managers of neighboring cities along a flood-prone river and make choices about building flood walls to protect their inhabitants. Simulated agents participate in dynamic real estate markets in which demand for property, and thus values and decisions to build, respond to experience with flooding over time. By reducing high-frequency low-magnitude flooding, flood walls may stimulate development, thus increasing tax revenues but also increasing vulnerability to uncommon floods that overtop the walls. Flood waves are launched stochastically and propagate downstream. Flood walls that restrict overbank flow at one city can increase the amplitude of a flood wave at neighboring cities, both up and downstream. We conducted a pilot experiment with a group of three pre-service teachers. The subjects successfully learned key concepts of risk tradeoffs and unintended consequences that can accompany flood-control measures. We also observed strong emotional responses, including hope, fear, and sense of loss. This emotional engagement with a model of coupled human-natural systems was very different from previous experiments on participatory simulations of purely natural systems for physics pedagogy. We conducted a second session in which the participants were expert engineers. We will present the results of these experiments and the

An operational procedure for rapid flood risk assessment in Europe

Science.gov (United States)

Dottori, Francesco; Kalas, Milan; Salamon, Peter; Bianchi, Alessandra; Alfieri, Lorenzo; Feyen, Luc

2017-07-01

The development of methods for rapid flood mapping and risk assessment is a key step to increase the usefulness of flood early warning systems and is crucial for effective emergency response and flood impact mitigation. Currently, flood early warning systems rarely include real-time components to assess potential impacts generated by forecasted flood events. To overcome this limitation, this study describes the benchmarking of an operational procedure for rapid flood risk assessment based on predictions issued by the European Flood Awareness System (EFAS). Daily streamflow forecasts produced for major European river networks are translated into event-based flood hazard maps using a large map catalogue derived from high-resolution hydrodynamic simulations. Flood hazard maps are then combined with exposure and vulnerability information, and the impacts of the forecasted flood events are evaluated in terms of flood-prone areas, economic damage and affected population, infrastructures and cities.An extensive testing of the operational procedure has been carried out by analysing the catastrophic floods of May 2014 in Bosnia-Herzegovina, Croatia and Serbia. The reliability of the flood mapping methodology is tested against satellite-based and report-based flood extent data, while modelled estimates of economic damage and affected population are compared against ground-based estimations. Finally, we evaluate the skill of risk estimates derived from EFAS flood forecasts with different lead times and combinations of probabilistic forecasts. Results highlight the potential of the real-time operational procedure in helping emergency response and management.

NOAA Weather Radio - All Hazards

Science.gov (United States)

Non-Zero All Hazards Logo Emergency Alert Description Event Codes Fact Sheet FAQ Organization Search -event information for all types of hazards: weather (e.g., tornadoes, floods), natural (e.g Management or Preparedness, civil defense, police or mayor/commissioner sets up linkages to send messages on

Mitigating flood exposure: Reducing disaster risk and trauma signature.

Science.gov (United States)

Shultz, James M; McLean, Andrew; Herberman Mash, Holly B; Rosen, Alexa; Kelly, Fiona; Solo-Gabriele, Helena M; Youngs, Georgia A; Jensen, Jessica; Bernal, Oscar; Neria, Yuval

2013-01-01

Introduction. In 2011, following heavy winter snowfall, two cities bordering two rivers in North Dakota, USA faced major flood threats. Flooding was foreseeable and predictable although the extent of risk was uncertain. One community, Fargo, situated in a shallow river basin, successfully mitigated and prevented flooding. For the other community, Minot, located in a deep river valley, prevention was not possible and downtown businesses and one-quarter of the homes were inundated, in the city's worst flood on record. We aimed at contrasting the respective hazards, vulnerabilities, stressors, psychological risk factors, psychosocial consequences, and disaster risk reduction strategies under conditions where flood prevention was, and was not, possible. Methods . We applied the "trauma signature analysis" (TSIG) approach to compare the hazard profiles, identify salient disaster stressors, document the key components of disaster risk reduction response, and examine indicators of community resilience. Results . Two demographically-comparable communities, Fargo and Minot, faced challenging river flood threats and exhibited effective coordination across community sectors. We examined the implementation of disaster risk reduction strategies in situations where coordinated citizen action was able to prevent disaster impact (hazard avoidance) compared to the more common scenario when unpreventable disaster strikes, causing destruction, harm, and distress. Across a range of indicators, it is clear that successful mitigation diminishes both physical and psychological impact, thereby reducing the trauma signature of the event. Conclusion . In contrast to experience of historic flooding in Minot, the city of Fargo succeeded in reducing the trauma signature by way of reducing risk through mitigation.

Future trends in flood risk in Indonesia - A probabilistic approach

Science.gov (United States)

Muis, Sanne; Guneralp, Burak; Jongman, Brenden; Ward, Philip

2014-05-01

Indonesia is one of the 10 most populous countries in the world and is highly vulnerable to (river) flooding. Catastrophic floods occur on a regular basis; total estimated damages were US 0.8 bn in 2010 and US 3 bn in 2013. Large parts of Greater Jakarta, the capital city, are annually subject to flooding. Flood risks (i.e. the product of hazard, exposure and vulnerability) are increasing due to rapid increases in exposure, such as strong population growth and ongoing economic development. The increase in risk may also be amplified by increasing flood hazards, such as increasing flood frequency and intensity due to climate change and land subsidence. The implementation of adaptation measures, such as the construction of dykes and strategic urban planning, may counteract these increasing trends. However, despite its importance for adaptation planning, a comprehensive assessment of current and future flood risk in Indonesia is lacking. This contribution addresses this issue and aims to provide insight into how socio-economic trends and climate change projections may shape future flood risks in Indonesia. Flood risk were calculated using an adapted version of the GLOFRIS global flood risk assessment model. Using this approach, we produced probabilistic maps of flood risks (i.e. annual expected damage) at a resolution of 30"x30" (ca. 1km x 1km at the equator). To represent flood exposure, we produced probabilistic projections of urban growth in a Monte-Carlo fashion based on probability density functions of projected population and GDP values for 2030. To represent flood hazard, inundation maps were computed using the hydrological-hydraulic component of GLOFRIS. These maps show flood inundation extent and depth for several return periods and were produced for several combinations of GCMs and future socioeconomic scenarios. Finally, the implementation of different adaptation strategies was incorporated into the model to explore to what extent adaptation may be able to

Flood disaster and protection measures in Turkey Case Study: May 1998 flood disaster at North Western Black Sea Region of Turkey

International Nuclear Information System (INIS)

Gurer, Ibrahim; Ozguier, Hamza

2004-01-01

Due to geographical location, geology, and topography, Turkey undergoes three main types of natural disasters related to gravity flows; floods, landslides, and snow avalanches. Flooding is second important natural hazard after earthquakes with 18 floods and 23 deaths per year, on average. During 20-21 May 1998, the rainfall which was equal to about four times of long-term mean annual rainfall total of north western Black Sea geographical region of Turkey affected 35.000 m 2 , damaged 1300 km highway, 600 km roads to the villages, and 60 km railway. After the recession of the flood waters, the field survey done proved that 12 highway bridges, 91 small bridges on village roads and 6900 highway culverts, 13.800 m retaining wall and about 500 houses were severely damaged. During the last five years, with the loans and credits provided by World Bank, a series of flood protection structures were designed and built for the rehabilitation of the region. Mostly concentrating on non-structural flood protection studies, a work programme has been drafted in this framework to develop flood management and to reduce or eliminate long-term risk and damage to people and their property from natural hazards and their effects. In this case study, the factors causing the flood disaster are given, and the flood event is analyzed from hydrologic and morphologic points of view. Also the different types of the flood protection measures are exemplified and the experience gained in controlling the flood damages is presented.(Author)

Simulating floods : On the application of a 2D-hydraulic model for flood hazard and risk assessment

NARCIS (Netherlands)

Alkema, D.

2007-01-01

Over the last decades, river floods in Europe seem to occur more frequently and are causing more and more economic and emotional damage. Understanding the processes causing flooding and the development of simulation models to evaluate countermeasures to control that damage are important issues. This

Urban sprawl and flooding in southern California

Science.gov (United States)

Rantz, S.E.

1970-01-01

The floods of January 1969 in south-coastal California provide a timely example of the effect of urban sprawl on flood damage. Despite recordbreaking, or near recordbreaking, stream discharges, damage was minimal in the older developed areas that are protected against inundation and debris damage by carefully planned flood-control facilities, including debris basins and flood-conveyance channels. By contrast, heavy damage occurred in areas of more recent urban sprawl, where the hazards of inundation and debris or landslide damage have not been taken into consideration, and where the improvement and development of drainage or flood-control facilities have not kept pace with expanding urbanization.

Flooding Fragility Experiments and Prediction

Energy Technology Data Exchange (ETDEWEB)

Smith, Curtis L. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tahhan, Antonio [Idaho National Lab. (INL), Idaho Falls, ID (United States); Muchmore, Cody [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nichols, Larinda [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bhandari, Bishwo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Pope, Chad [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-09-01

This report describes the work that has been performed on flooding fragility, both the experimental tests being carried out and the probabilistic fragility predictive models being produced in order to use the text results. Flooding experiments involving full-scale doors have commenced in the Portal Evaluation Tank. The goal of these experiments is to develop a full-scale component flooding experiment protocol and to acquire data that can be used to create Bayesian regression models representing the fragility of these components. This work is in support of the Risk-Informed Safety Margin Characterization (RISMC) Pathway external hazards evaluation research and development.

INFLUENCE OF DEM IN WATERSHED MANAGEMENT AS FLOOD ZONATION MAPPING

Directory of Open Access Journals (Sweden)

M. Alrajhi

2016-06-01

Full Text Available Despite of valuable efforts from working groups and research organizations towards flood hazard reduction through its program, still minimal diminution from these hazards has been realized. This is mainly due to the fact that with rapid increase in population and urbanization coupled with climate change, flood hazards are becoming increasingly catastrophic. Therefore there is a need to understand and access flood hazards and develop means to deal with it through proper preparations, and preventive measures. To achieve this aim, Geographical Information System (GIS, geospatial and hydrological models were used as tools to tackle with influence of flash floods in the Kingdom of Saudi Arabia due to existence of large valleys (Wadis which is a matter of great concern. In this research paper, Digital Elevation Models (DEMs of different resolution (30m, 20m,10m and 5m have been used, which have proven to be valuable tool for the topographic parameterization of hydrological models which are the basis for any flood modelling process. The DEM was used as input for performing spatial analysis and obtaining derivative products and delineate watershed characteristics of the study area using ArcGIS desktop and its Arc Hydro extension tools to check comparability of different elevation models for flood Zonation mapping. The derived drainage patterns have been overlaid over aerial imagery of study area, to check influence of greater amount of precipitation which can turn into massive destructions. The flow accumulation maps derived provide zones of highest accumulation and possible flow directions. This approach provide simplified means of predicting extent of inundation during flood events for emergency action especially for large areas because of large coverage area of the remotely sensed data.

Emotions, trust, and perceived risk: affective and cognitive routes to flood preparedness behavior.

Science.gov (United States)

Terpstra, Teun

2011-10-01

Despite the prognoses of the effects of global warming (e.g., rising sea levels, increasing river discharges), few international studies have addressed how flood preparedness should be stimulated among private citizens. This article aims to predict Dutch citizens' flood preparedness intentions by testing a path model, including previous flood hazard experiences, trust in public flood protection, and flood risk perceptions (both affective and cognitive components). Data were collected through questionnaire surveys in two coastal communities (n= 169, n= 244) and in one river area community (n= 658). Causal relations were tested by means of structural equation modeling (SEM). Overall, the results indicate that both cognitive and affective mechanisms influence citizens' preparedness intentions. First, a higher level of trust reduces citizens' perceptions of flood likelihood, which in turn hampers their flood preparedness intentions (cognitive route). Second, trust also lessens the amount of dread evoked by flood risk, which in turn impedes flood preparedness intentions (affective route). Moreover, the affective route showed that levels of dread were especially influenced by citizens' negative and positive emotions related to their previous flood hazard experiences. Negative emotions most often reflected fear and powerlessness, while positive emotions most frequently reflected feelings of solidarity. The results are consistent with the affect heuristic and the historical context of Dutch flood risk management. The great challenge for flood risk management is the accommodation of both cognitive and affective mechanisms in risk communications, especially when most people lack an emotional basis stemming from previous flood hazard events. © 2011 Society for Risk Analysis.

Quantifying the effect of autonomous adaptation to global river flood projections: application to future flood risk assessments

Science.gov (United States)

Kinoshita, Youhei; Tanoue, Masahiro; Watanabe, Satoshi; Hirabayashi, Yukiko

2018-01-01

This study represents the first attempt to quantify the effects of autonomous adaptation on the projection of global flood hazards and to assess future flood risk by including this effect. A vulnerability scenario, which varies according to the autonomous adaptation effect for conventional disaster mitigation efforts, was developed based on historical vulnerability values derived from flood damage records and a river inundation simulation. Coupled with general circulation model outputs and future socioeconomic scenarios, potential future flood fatalities and economic loss were estimated. By including the effect of autonomous adaptation, our multimodel ensemble estimates projected a 2.0% decrease in potential flood fatalities and an 821% increase in potential economic losses by 2100 under the highest emission scenario together with a large population increase. Vulnerability changes reduced potential flood consequences by 64%-72% in terms of potential fatalities and 28%-42% in terms of potential economic losses by 2100. Although socioeconomic changes made the greatest contribution to the potential increased consequences of future floods, about a half of the increase of potential economic losses was mitigated by autonomous adaptation. There is a clear and positive relationship between the global temperature increase from the pre-industrial level and the estimated mean potential flood economic loss, while there is a negative relationship with potential fatalities due to the autonomous adaptation effect. A bootstrapping analysis suggests a significant increase in potential flood fatalities (+5.7%) without any adaptation if the temperature increases by 1.5 °C-2.0 °C, whereas the increase in potential economic loss (+0.9%) was not significant. Our method enables the effects of autonomous adaptation and additional adaptation efforts on climate-induced hazards to be distinguished, which would be essential for the accurate estimation of the cost of adaptation to

Vehicles instability criteria for flood risk assessment of a street network

Directory of Open Access Journals (Sweden)

C. Arrighi

2016-05-01

Full Text Available The mutual interaction between floods and human activity is a process, which has been evolving over history and has shaped flood risk pathways. In developed countries, many events have illustrated that the majority of the fatalities during a flood occurs in a vehicle, which is considered as a safe shelter but it may turn into a trap for several combinations of water depth and velocity. Thus, driving a car in floodwaters is recognized as the most crucial aggravating factor for people safety. On the other hand, the entrainment of vehicles may locally cause obstructions to the flow and induce the collapse of infrastructures. Flood risk to vehicles can be defined as the combination of the probability of a vehicle of being swept away (i.e. the hazard and the actual traffic/parking density, i.e. the vulnerability. Hazard for vehicles can be assessed through the spatial identification and mapping of the critical conditions for vehicles incipient motion. This analysis requires a flood map with information on water depth and velocity and consistent instability criteria accounting for flood and vehicles characteristics. Vulnerability is evaluated thanks to the road network and traffic data. Therefore, vehicles flood risk mapping can support people's education and management practices in order to reduce the casualties. In this work, a flood hazard classification for vehicles is introduced and an application to a real case study is presented and discussed.

Vehicles instability criteria for flood risk assessment of a street network

Science.gov (United States)

Arrighi, Chiara; Huybrechts, Nicolas; Ouahsine, Abdellatif; Chassé, Patrick; Oumeraci, Hocine; Castelli, Fabio

2016-05-01

The mutual interaction between floods and human activity is a process, which has been evolving over history and has shaped flood risk pathways. In developed countries, many events have illustrated that the majority of the fatalities during a flood occurs in a vehicle, which is considered as a safe shelter but it may turn into a trap for several combinations of water depth and velocity. Thus, driving a car in floodwaters is recognized as the most crucial aggravating factor for people safety. On the other hand, the entrainment of vehicles may locally cause obstructions to the flow and induce the collapse of infrastructures. Flood risk to vehicles can be defined as the combination of the probability of a vehicle of being swept away (i.e. the hazard) and the actual traffic/parking density, i.e. the vulnerability. Hazard for vehicles can be assessed through the spatial identification and mapping of the critical conditions for vehicles incipient motion. This analysis requires a flood map with information on water depth and velocity and consistent instability criteria accounting for flood and vehicles characteristics. Vulnerability is evaluated thanks to the road network and traffic data. Therefore, vehicles flood risk mapping can support people's education and management practices in order to reduce the casualties. In this work, a flood hazard classification for vehicles is introduced and an application to a real case study is presented and discussed.

Flood Losses Associated with Winter Storms in the U.S. Northeast

Science.gov (United States)

Ting, M.; Shimkus, C.

2015-12-01

Winter storms pose a number of hazards to coastal communities in the U.S. Northeast including heavy rain, snow, strong wind, cold temperatures, and flooding. These hazards can cause millions in property damages from one storm alone. This study addresses the impacts of winter storms from 2001 - 2012 on coastal counties in the U.S. Northeast and underscores the significant economic consequences extreme winter storms have on property. The analysis on the types of hazards (floods, strong wind, snow, etc.) and associated damage from the National Climatic Data Center Storm Events Database indicates that floods were responsible for the highest damages. This finding suggests that winter storm vulnerability could grow in the future as precipitation intensity increases and sea level rise exacerbate flood losses. Flood loss maps are constructed based on damage amount, which can be compared to the flood exposure maps constructed by the NOAA Office of Coastal Management. Interesting agreements and discrepancies exist between the two methods, which warrant further examination. Furthermore, flood losses often came from storms characterized as heavy precipitation storms and strong surge storms, and sometimes both, illustrating the compounding effect of flood risks in the region. While New Jersey counties experienced the most damage per unit area, there is no discernable connection between population density and damage amount, which suggests that societal impacts may rely less on population characteristics and more on infrastructure types and property values, which vary throughout the region.

The credibility challenge for global fluvial flood risk analysis

NARCIS (Netherlands)

Trigg, M.A.; Birch, C.E.; Neal, J.C.; Bates, P.D.; Smith, A.; Sampson, C.C.; Yamazaki, D.; Hirabayashi, Y.; Pappenberger, F.; Dutra, E.; Ward, P.J.; Winsemius, H.C.; Salamon, P.; Dottori, F.; Rudari, R.; Kappes, M.S.; Simpson, A.L.; Hadzilacos, G.; Fewtrell, T.J.

2016-01-01

Quantifying flood hazard is an essential component of resilience planning, emergency response, and mitigation, including insurance. Traditionally undertaken at catchment and national scales, recently, efforts have intensified to estimate flood risk globally to better allow consistent and equitable

Interactions between land use and flood management in the Chi River Basin

NARCIS (Netherlands)

Kuntiyawichai, K.

2012-01-01

The damages and hardships caused by floods and flooding remain an issue and are continuously increasing in the Chi River Basin, Thailand. It is difficult to make an accurate assessment of the costs and consequences associated with floods. However, flood hazards can also be seen as an opportunity, a

International Severe Weather and Flash Flood Hazard Early Warning Systems—Leveraging Coordination, Cooperation, and Partnerships through a Hydrometeorological Project in Southern Africa

Directory of Open Access Journals (Sweden)

Robert Jubach

2016-06-01

Full Text Available Climate, weather and water hazards do not recognize national boundaries. Transboundary/regional programs and cooperation are essential to reduce the loss of lives and damage to livelihoods when facing these hazards. The development and implementation of systems to provide early warnings for severe weather events such as cyclones and flash floods requires data and information sharing in real time, and coordination among the government agencies at all levels. Within a country, this includes local, municipal, provincial-to-national levels as well as regional and international entities involved in hydrometeorological services and Disaster Risk Reduction (DRR. Of key importance are the National Meteorological and Hydrologic Services (NMHSs. The NMHS is generally the authority solely responsible for issuing warnings for these hazards. However, in many regions of the world, the linkages and interfaces between the NMHS and other agencies are weak or non-existent. Therefore, there is a critical need to assess, strengthen, and formalize collaborations when addressing the concept of reducing risk and impacts from severe weather and floods. The U.S. Agency for International Development/Office of U.S. Foreign Disaster Assistance; the United Nations World Meteorological Organization (WMO; the WMO Southern Africa Regional Specialized Meteorological Center, hosted by the South African Weather Service; the U.S. National Oceanic and Atmospheric Administration/National Weather Service and the Hydrologic Research Center (a non-profit corporation are currently implementing a project working with Southern Africa NMHSs on addressing this gap. The project aims to strengthen coordination and collaboration mechanisms from national to local levels. The project partners are working with the NMHSs to apply and implement appropriate tools and infrastructure to enhance currently operational severe weather and flash flood early warning systems in each country in support of

Assessing Future Flood Hazards for Adaptation Planning in a Northern European Coastal Community

DEFF Research Database (Denmark)

Sørensen, Carlo Sass; Broge, Niels H.; Molgaard, Mads R.

2016-01-01

From a transdisciplinary approach in the town of Thyboron, Denmark, we investigate couplings between sea state (i.e., mean and extreme) and flooding hazards today and ahead. This includes analyses of change and variability in the groundwater table, precipitation, land motion, geotechnical ground ......, and it will provide for more holistic solutions that both serve to protect the town and allow for business development and better municipal planning ahead....... properties, sewerage systems and other infrastructure to outline a more complete platform for the integration of knowledge into climate adaptation schemes at this highly vulnerable coastal location. It involves the engagement of the main stakeholders who, although having different responsibilities, interests......, needs of knowledge and data, and different timeframes for investment and planning, must join in a common appraisal of the challenges faced ahead to provide for better adaptation measures. Apart from obvious adverse effects from future storm surge events, knowledge about the coupled effects...

Increasing resilience through participative flood risk map design

Science.gov (United States)

Fuchs, Sven; Spira, Yvonne; Stickler, Therese

2013-04-01

In recent years, an increasing number of flood hazards has shown to the European Commission and the Member States of the European Union the importance of flood risk management strategies in order to reduce losses and to protect the environment and the citizens. Exposure to floods as well as flood vulnerability might increase across Europe due to the ongoing economic development in many EU countries. Thus even without taking climate change into account an increase of flood disasters in Europe might be foreseeable. These circumstances have produced a reaction in the European Commission, and a Directive on the Assessment and Management of Flood Risks was issued as one of the three components of the European Action Programme on Flood Risk Management. Floods have the potential to jeopardise economic development, above all due to an increase of human activities in floodplains and the reduction of natural water retention by land use activities. As a result, an increase in the likelihood and adverse impacts of flood events is expected. Therefore, concentrated action is needed at the European level to avoid severe impacts on human life and property. In order to have an effective tool available for gathering information, as well as a valuable basis for priority setting and further technical, financial and political decisions regarding flood risk mitigation and management, it is necessary to provide for the establishment of flood risk maps which show the potential adverse consequences associated with different flood scenarios. So far, hazard and risk maps are compiled in terms of a top-down linear approach: planning authorities take the responsibility to create and implement these maps on different national and local scales, and the general public will only be informed about the outcomes (EU Floods Directive, Article 10). For the flood risk management plans, however, an "active involvement of interested parties" is required, which means at least some kind of multilateral

Hierarchical Modelling of Flood Risk for Engineering Decision Analysis

DEFF Research Database (Denmark)

Custer, Rocco

protection structures in the hierarchical flood protection system - is identified. To optimise the design of protection structures, fragility and vulnerability models must allow for consideration of decision alternatives. While such vulnerability models are available for large protection structures (e...... systems, as well as the implementation of the flood risk analysis methodology and the vulnerability modelling approach are illustrated with an example application. In summary, the present thesis provides a characterisation of hierarchical flood protection systems as well as several methodologies to model...... and robust. Traditional risk management solutions, e.g. dike construction, are not particularly flexible, as they are difficult to adapt to changing risk. Conversely, the recent concept of integrated flood risk management, entailing a combination of several structural and non-structural risk management...

Quantifying the key factors that create road flooding.

Science.gov (United States)

2013-01-01

Road flooding is a serious operational hazard in the low-lying areas of southern Louisiana. This hazard is especially acute for the regions emergency evacuation routes, which must be accessible by coastal residents who plan evacuations ahead of an...

Flash flood forecasting, warning and risk management: the HYDRATE project

International Nuclear Information System (INIS)

Borga, M.; Anagnostou, E.N.; Bloeschl, G.; Creutin, J.-D.

2011-01-01

Highlights: → We characterize flash flood events in various regions of Europe. → We provide guidance to improve observations and monitoring of flash floods. → Flash floods are associated to orography and are influenced by initial soil moisture conditions. → Models for flash flood forecasting and flash flood hazard assessment are illustrated and discussed. → We examine implications for flood risk policy and discuss recommendations received from end users. - Abstract: The management of flash flood hazards and risks is a critical component of public safety and quality of life. Flash-floods develop at space and time scales that conventional observation systems are not able to monitor for rainfall and river discharge. Consequently, the atmospheric and hydrological generating mechanisms of flash-floods are poorly understood, leading to highly uncertain forecasts of these events. The objective of the HYDRATE project has been to improve the scientific basis of flash flood forecasting by advancing and harmonising a European-wide innovative flash flood observation strategy and developing a coherent set of technologies and tools for effective early warning systems. To this end, the project included actions on the organization of the existing flash flood data patrimony across Europe. The final aim of HYDRATE was to enhance the capability of flash flood forecasting in ungauged basins by exploiting the extended availability of flash flood data and the improved process understanding. This paper provides a review of the work conducted in HYDRATE with a special emphasis on how this body of research can contribute to guide the policy-life cycle concerning flash flood risk management.

Understanding the geomorphology of macrochannel systems for flood risk management in Queensland, Australia

Science.gov (United States)

Thompson, Chris; Croke, Jacky

2016-04-01

The year 2010-2011 was the wettest on record for the state of Queensland, Australia producing catastrophic floods. A tropical low pressure system in 2013 delivered further extreme flood events across South East Queensland (SEQ) which prompted state and local governments to conduct studies into flood magnitude and frequency in the region and catchment factors contributing to flood hazards. The floods in the region are strongly influenced by El Nino-Southern Oscillation (ENSO) phenomenon, but also modulated by the Interdecadal Pacific Oscillation (IPO) which leads to flood and drought dominated regimes and high hydrological variability. One geomorphic feature in particular exerted a significant control on the transmission speed, the magnitude of flood inundation and resultant landscape resilience. This feature was referred to as a 'macrochannel', a term used to describe a 'large-channel' which has bankfull recurrence intervals generally greater than 10 years. The macrochannels display non-linear downstream hydraulic geometry which leads to zones of flood expansion (when hydraulic geometry decreases) and zones of flood contraction (when hydraulic geometry increases). The pattern of contraction and expansion zones determines flood hazard zones. The floods caused significant wet flow bank mass failures that mobilised over 1,000,000 m3 of sediment in one subcatchment. Results suggest that the wetflow bank mass failures are a stage in a cyclical evolution process which maintains the macrochannel morphology, hence channel resilience to floods. Chronological investigations further show the macrochannels are laterally stable and identify periods of heightened flood activity over the past millennium and upper limits on flood magnitude. This paper elaborates on the results of the geomorphic investigations on Lockyer Creek in SEQ and how the results have alerted managers and policy makers to the different flood responses of these systems and how flood risk management plans can

Development of a flood-induced health risk prediction model for Africa

Science.gov (United States)

Lee, D.; Block, P. J.

2017-12-01

Globally, many floods occur in developing or tropical regions where the impact on public health is substantial, including death and injury, drinking water, endemic disease, and so on. Although these flood impacts on public health have been investigated, integrated management of floods and flood-induced health risks is technically and institutionally limited. Specifically, while the use of climatic and hydrologic forecasts for disaster management has been highlighted, analogous predictions for forecasting the magnitude and impact of health risks are lacking, as is the infrastructure for health early warning systems, particularly in developing countries. In this study, we develop flood-induced health risk prediction model for African regions using season-ahead flood predictions with climate drivers and a variety of physical and socio-economic information, such as local hazard, exposure, resilience, and health vulnerability indicators. Skillful prediction of flood and flood-induced health risks can contribute to practical pre- and post-disaster responses in both local- and global-scales, and may eventually be integrated into multi-hazard early warning systems for informed advanced planning and management. This is especially attractive for areas with limited observations and/or little capacity to develop flood-induced health risk warning systems.

An influence diagram for urban flood risk assessment through pluvial flood hazards under non-stationary conditions

DEFF Research Database (Denmark)

Åström, Helena Lisa Alexandra; Friis Hansen, P.; Garrè, Luca

2014-01-01

Urban flooding introduces significant risk to society. Non-stationarity leads to increased uncertainty and this is challenging to include in actual decision-making. The primary objective of this study was to develop a risk assessment and decision support framework for pluvial urban flood risk under...... non-stationary conditions using an influence diagram (ID) which is a Bayesian network (BN) extended with decision and utility nodes. Non-stationarity is considered to be the influence of climate change where extreme precipitation patterns change over time. The overall risk is quantified in monetary...... terms expressed as expected annual damage. The network is dynamic in as much as it assesses risk at different points in time. The framework provides means for decision-makers to assess how different decisions on flood adaptation affect the risk now and in the future. The result from the ID was extended...

Flooding in the Context of the Barotse People of the Upper Zambezi ...

African Journals Online (AJOL)

Jenny

Much of the historical and contemporary view of flooding is that it is a hazard .... thought of 'taming the flood' in different ways, as illustrated by Purseglove (1989). .... purposeful flooding of the water meadows in the United Kingdom, which can ...

Flood maps in Europe – methods, availability and use

Directory of Open Access Journals (Sweden)

J. C. J. H. Aerts

2009-03-01

Full Text Available To support the transition from traditional flood defence strategies to a flood risk management approach at the basin scale in Europe, the EU has adopted a new Directive (2007/60/EC at the end of 2007. One of the major tasks which member states must carry out in order to comply with this Directive is to map flood hazards and risks in their territory, which will form the basis of future flood risk management plans. This paper gives an overview of existing flood mapping practices in 29 countries in Europe and shows what maps are already available and how such maps are used. Roughly half of the countries considered have maps covering as good as their entire territory, and another third have maps covering significant parts of their territory. Only five countries have very limited or no flood maps available yet. Of the different flood maps distinguished, it appears that flood extent maps are the most commonly produced floods maps (in 23 countries, but flood depth maps are also regularly created (in seven countries. Very few countries have developed flood risk maps that include information on the consequences of flooding. The available flood maps are mostly developed by governmental organizations and primarily used for emergency planning, spatial planning, and awareness raising. In spatial planning, flood zones delimited on flood maps mainly serve as guidelines and are not binding. Even in the few countries (e.g. France, Poland where there is a legal basis to regulate floodplain developments using flood zones, practical problems are often faced which reduce the mitigating effect of such binding legislation. Flood maps, also mainly extent maps, are also created by the insurance industry in Europe and used to determine insurability, differentiate premiums, or to assess long-term financial solvency. Finally, flood maps are also produced by international river commissions. With respect to the EU Flood Directive, many countries already have a good starting

Flash floods warning technique based on wireless communication networks data

Science.gov (United States)

David, Noam; Alpert, Pinhas; Messer, Hagit

2010-05-01

Flash floods can occur throughout or subsequent to rainfall events, particularly in cases where the precipitation is of high-intensity. Unfortunately, each year these floods cause severe property damage and heavy casualties. At present, there are no sufficient real time flash flood warning facilities found to cope with this phenomenon. Here we show the tremendous potential of flash floods advanced warning based on precipitation measurements of commercial microwave links. As was recently shown, wireless communication networks supply high resolution precipitation measurements at ground level while often being situated in flood prone areas, covering large parts of these hazardous regions. We present the flash flood warning potential of the wireless communication system for two different cases when floods occurred at the Judean desert and at the northern Negev in Israel. In both cases, an advanced warning regarding the hazard could have been announced based on this system. • This research was supported by THE ISRAEL SCIENCE FOUNDATION (grant No. 173/08). This work was also supported by a grant from the Yeshaya Horowitz Association, Jerusalem. Additional support was given by the PROCEMA-BMBF project and by the GLOWA-JR BMBF project.

Mapping Infected Area after a Flash-Flooding Storm Using Multi Criteria Analysis and Spectral Indices

Science.gov (United States)

Al-Akad, S.; Akensous, Y.; Hakdaoui, M.

2017-11-01

This research article is summarize the applications of remote sensing and GIS to study the urban floods risk in Al Mukalla. Satellite acquisition of a flood event on October 2015 in Al Mukalla (Yemen) by using flood risk mapping techniques illustrate the potential risk present in this city. Satellite images (The Landsat and DEM images data were atmospherically corrected, radiometric corrected, and geometric and topographic distortions rectified.) are used for flood risk mapping to afford a hazard (vulnerability) map. This map is provided by applying image-processing techniques and using geographic information system (GIS) environment also the application of NDVI, NDWI index, and a method to estimate the flood-hazard areas. Four factors were considered in order to estimate the spatial distribution of the hazardous areas: flow accumulation, slope, land use, geology and elevation. The multi-criteria analysis, allowing to deal with vulnerability to flooding, as well as mapping areas at the risk of flooding of the city Al Mukalla. The main object of this research is to provide a simple and rapid method to reduce and manage the risks caused by flood in Yemen by take as example the city of Al Mukalla.

Introduction to Plate Boundaries and Natural Hazards

NARCIS (Netherlands)

Duarte, João C.; Schellart, Wouter P.

2016-01-01

A great variety of natural hazards occur on Earth, including earthquakes, volcanic eruptions, tsunamis, landslides, floods, fires, tornadoes, hurricanes, and avalanches. The most destructive of these hazards, earthquakes, tsunamis, and volcanic eruptions, are mostly associated with tectonic plate

A Theory on Urban Resilience to Floods - A Basis for Alternative Planning Practices

Directory of Open Access Journals (Sweden)

Kuei-Hsien Liao

2012-12-01

Full Text Available River cities require a management approach based on resilience to floods rather than on resistance. Resisting floods by means of levees, dams, and channelization neglects inherent uncertainties arising from human-nature couplings and fails to address the extreme events that are expected to increase with climate change, and is thereby not a reliable approach to long-term flood safety. By applying resilience theory to address system persistence through changes, I develop a theory on "urban resilience to floods" as an alternative framework for urban flood hazard management. Urban resilience to floods is defined as a city's capacity to tolerate flooding and to reorganize should physical damage and socioeconomic disruption occur, so as to prevent deaths and injuries and maintain current socioeconomic identity. It derives from living with periodic floods as learning opportunities to prepare the city for extreme ones. The theory of urban resilience to floods challenges the conventional wisdom that cities cannot live without flood control, which in effect erodes resilience. To operationalize the theory for planning practice, a surrogate measure - the percent floodable area - is developed for assessing urban resilience to floods. To enable natural floodplain functions to build urban resilience to floods, flood adaptation is advocated in order to replace flood control for mitigating flood hazards.

Implications of Sea Level Rise on Coastal Flood Hazards

Science.gov (United States)

Roeber, V.; Li, N.; Cheung, K.; Lane, P.; Evans, R. L.; Donnelly, J. P.; Ashton, A. D.

2012-12-01

Recent global and local projections suggest the sea level will be on the order of 1 m or higher than the current level by the end of the century. Coastal communities and ecosystems in low-lying areas are vulnerable to impacts resulting from hurricane or large swell events in combination with sea-level rise. This study presents the implementation and results of an integrated numerical modeling package to delineate coastal inundation due to storm landfalls at future sea levels. The modeling package utilizes a suite of numerical models to capture both large-scale phenomena in the open ocean and small-scale processes in coastal areas. It contains four components to simulate (1) meteorological conditions, (2) astronomical tides and surge, (3) wave generation, propagation, and nearshore transformation, and (4) surf-zone processes and inundation onto dry land associated with a storm event. Important aspects of this package are the two-way coupling of a spectral wave model and a storm surge model as well as a detailed representation of surf and swash zone dynamics by a higher-order Boussinesq-type wave model. The package was validated with field data from Hurricane Ivan of 2005 on the US Gulf coast and applied to tropical and extratropical storm scenarios respectively at Eglin, Florida and Camp Lejeune, North Carolina. The results show a nonlinear increase of storm surge level and nearshore wave energy with a rising sea level. The exacerbated flood hazard can have major consequences for coastal communities with respect to erosion and damage to infrastructure.

Framework for probabilistic flood risk assessment in an Alpine region

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Schneeberger, Klaus; Huttenlau, Matthias; Steinberger, Thomas; Achleitner, Stefan; Stötter, Johann

2014-05-01

Flooding is among the natural hazards that regularly cause significant losses to property and human lives. The assessment of flood risk delivers crucial information for all participants involved in flood risk management and especially for local authorities and insurance companies in order to estimate the possible flood losses. Therefore a framework for assessing flood risk has been developed and is introduced with the presented contribution. Flood risk is thereby defined as combination of the probability of flood events and of potential flood damages. The probability of occurrence is described through the spatial and temporal characterisation of flood. The potential flood damages are determined in the course of vulnerability assessment, whereas, the exposure and the vulnerability of the elements at risks are considered. Direct costs caused by flooding with the focus on residential building are analysed. The innovative part of this contribution lies on the development of a framework which takes the probability of flood events and their spatio-temporal characteristic into account. Usually the probability of flooding will be determined by means of recurrence intervals for an entire catchment without any spatial variation. This may lead to a misinterpretation of the flood risk. Within the presented framework the probabilistic flood risk assessment is based on analysis of a large number of spatial correlated flood events. Since the number of historic flood events is relatively small additional events have to be generated synthetically. This temporal extrapolation is realised by means of the method proposed by Heffernan and Tawn (2004). It is used to generate a large number of possible spatial correlated flood events within a larger catchment. The approach is based on the modelling of multivariate extremes considering the spatial dependence structure of flood events. The input for this approach are time series derived from river gauging stations. In a next step the

Integration of rainfall/runoff and geomorphological analyses flood hazard in small catchments: case studies from the southern Apennines (Italy)

Science.gov (United States)

Palumbo, Manuela; Ascione, Alessandra; Santangelo, Nicoletta; Santo, Antonio

2017-04-01

We present the first results of an analysis of flood hazard in ungauged mountain catchments that are associated with intensely urbanized alluvial fans. Assessment of hydrological hazard has been based on the integration of rainfall/runoff modelling of drainage basins with geomorphological analysis and mapping. Some small and steep, ungauged mountain catchments located in various areas of the southern Apennines, in southern Italy, have been chosen as test sites. In the last centuries, the selected basins have been subject to heavy and intense precipitation events, which have caused flash floods with serious damages in the correlated alluvial fan areas. Available spatial information (regional technical maps, DEMs, land use maps, geological/lithological maps, orthophotos) and an automated GIS-based procedure (ArcGis tools and ArcHydro tools) have been used to extract morphological, hydrological and hydraulic parameters. Such parameters have been used to run the HEC (Hydrologic Engineering Center of the US Army Corps of Engineers) software (GeoHMS, GeoRAS, HMS and RAS) based on rainfall-runoff models, which have allowed the hydrological and hydraulic simulations. As the floods occurred in the studied catchments have been debris flows dominated, the solid load simulation has been also performed. In order to validate the simulations, we have compared results of the modelling with the effects produced by past floods. Such effects have been quantified through estimations of both the sediment volumes within each catchment that have the potential to be mobilised (pre-event) during a sediment transfer event, and the volume of sediments delivered by the debris flows at basins' outlets (post-event). The post-event sediment volume has been quantified through post-event surveys and Lidar data. Evaluation of the pre-event sediment volumes in single catchments has been based on mapping of sediment storages that may constitute source zones of bed load transport and debris flows. For

Uncertainty quantification in flood risk assessment

Science.gov (United States)

Blöschl, Günter; Hall, Julia; Kiss, Andrea; Parajka, Juraj; Perdigão, Rui A. P.; Rogger, Magdalena; Salinas, José Luis; Viglione, Alberto

2017-04-01

Uncertainty is inherent to flood risk assessments because of the complexity of the human-water system, which is characterised by nonlinearities and interdependencies, because of limited knowledge about system properties and because of cognitive biases in human perception and decision-making. On top of the uncertainty associated with the assessment of the existing risk to extreme events, additional uncertainty arises because of temporal changes in the system due to climate change, modifications of the environment, population growth and the associated increase in assets. Novel risk assessment concepts are needed that take into account all these sources of uncertainty. They should be based on the understanding of how flood extremes are generated and how they change over time. They should also account for the dynamics of risk perception of decision makers and population in the floodplains. In this talk we discuss these novel risk assessment concepts through examples from Flood Frequency Hydrology, Socio-Hydrology and Predictions Under Change. We believe that uncertainty quantification in flood risk assessment should lead to a robust approach of integrated flood risk management aiming at enhancing resilience rather than searching for optimal defense strategies.

Analyzing Future Flooding under Climate Change Scenario using CMIP5 Streamflow Data

Science.gov (United States)

Parajuli, Ranjan; Nyaupane, Narayan; Kalra, Ajay

2017-12-01

Flooding is a severe and costlier natural hazard. The effect of climate change has intensified the scenario in recent years. Flood prevention practice along with a proper understanding of flooding event can mitigate the risk of such hazard. The floodplain mapping is one of the technique to quantify the severity of the flooding. Carson City, which is one of the agricultural areas in the desert of Nevada has experienced peak flood in the recent year. The underlying probability distribution for the area, latest Coupled Model Intercomparison Project (CMIP5) streamflow data of Carson River were analyzed for 27 different statistical distributions. The best-fitted distribution underlying was used to forecast the 100yr flood (design flood). The data from 1950-2099 derived from 31 model and total 97 projections were used to predict the future streamflow. Delta change method is adopted to quantify the amount of future (2050-2099) flood. To determine the extent of flooding 3 scenarios (i) historic design flood, (ii) 500yr flood and (iii) future 100yr flood were routed on an HEC-RAS model, prepared using available terrain data. Some of the climate projection shows an extreme increase in future design flood. This study suggests an approach to quantify the future flood and floodplain using climate model projections. The study would provide helpful information to the facility manager, design engineer, and stakeholders.

Flood hazards analysis based on changes of hydrodynamic processes in fluvial systems of Sao Paulo, Brazil.

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Simas, Iury; Rodrigues, Cleide

2016-04-01

The metropolis of Sao Paulo, with its 7940 Km² and over 20 million inhabitants, is increasingly being consolidated with disregard for the dynamics of its fluvial systems and natural limitations imposed by fluvial terraces, floodplains and slopes. Events such as floods and flash floods became particularly persistent mainly in socially and environmentally vulnerable areas. The Aricanduva River basin was selected as the ideal area for the development of the flood hazard analysis since it presents the main geological and geomorphological features found in the urban site. According to studies carried out by Anthropic Geomorphology approach in São Paulo, to study this phenomenon is necessary to take into account the original hydromorphological systems and its functional conditions, as well as in which dimensions the Anthropic factor changes the balance between the main variables of surface processes. Considering those principles, an alternative model of geographical data was proposed and enabled to identify the role of different driving forces in terms of spatial conditioning of certain flood events. Spatial relationships between different variables, such as anthropogenic and original morphology, were analyzed for that purpose in addition to climate data. The surface hydrodynamic tendency spatial model conceived for this study takes as key variables: 1- The land use present at the observed date combined with the predominant lithological group, represented by a value ranging 0-100, based on indexes of the National Soil Conservation Service (NSCS-USA) and the Hydraulic Technology Center Foundation (FCTH-Brazil) to determine the resulting balance of runoff/infiltration. 2- The original slope, applying thresholds from which it's possible to determine greater tendency for runoff (in percents). 3- The minimal features of relief, combining the curvature of surface in plant and profile. Those three key variables were combined in a Geographic Information System in a series of

Upstream Structural Management Measures for an Urban Area Flooding in Turkey and their Consequences on Flood Risk Management

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Akyurek, Z.; Bozoglu, B.; Girayhan, T.

2015-12-01

Flooding has the potential to cause significant impacts to economic activities as well as to disrupt or displace populations. Changing climate regimes such as extreme precipitation events increase flood vulnerability and put additional stresses on infrastructure. In this study the flood modelling in an urbanized area, namely Samsun-Terme in Blacksea region of Turkey is done. MIKE21 with flexible grid is used in 2- dimensional shallow water flow modelling. 1/1000 scaled maps with the buildings for the urbanized area and 1/5000 scaled maps for the rural parts are used to obtain DTM needed in the flood modelling. The bathymetry of the river is obtained from additional surveys. The main river passing through the urbanized area has a capacity of Q5 according to the design discharge obtained by simple ungauged discharge estimation depending on catchment area only. The effects of the available structures like bridges across the river on the flooding are presented. The upstream structural measures are studied on scenario basis. Four sub-catchments of Terme River are considered as contributing the downstream flooding. The existing circumstance of the Terme River states that the meanders of the river have a major effect on the flood situation and lead to approximately 35% reduction in the peak discharge between upstream and downstream of the river. It is observed that if the flow from the upstream catchments can be retarded through a detention pond constructed in at least two of the upstream catchments, estimated Q100 flood can be conveyed by the river without overtopping from the river channel. The operation of the upstream detention ponds and the scenarios to convey Q500 without causing flooding are also presented. Structural management measures to address changes in flood characteristics in water management planning are discussed. Flood risk is obtained by using the flood hazard maps and water depth-damage functions plotted for a variety of building types and occupancies

FloodProBE: technologies for improved safety of the built environment in relation to flood events

International Nuclear Information System (INIS)

Ree, C.C.D.F. van; Van, M.A.; Heilemann, K.; Morris, M.W.; Royet, P.; Zevenbergen, C.

2011-01-01

The FloodProBE project started as a FP7 research project in November 2009. Floods, together with wind related storms, are considered the major natural hazard in the EU in terms of risk to people and assets. In order to adapt urban areas (in river and coastal zones) to prevent flooding or to be better prepared for floods, decision makers need to determine how to upgrade flood defences and increasing flood resilience of protected buildings and critical infrastructure (power supplies, communications, water, transport, etc.) and assess the expected risk reduction from these measures. The aim of the FloodProBE-project is to improve knowledge on flood resilience and flood protection performance for balancing investments in flood risk management in urban areas. To this end, technologies, methods and tools for assessment purposes and for the adaptation of new and existing buildings and critical infrastructure are developed, tested and disseminated. Three priority areas are addressed by FloodProBE. These are: (i) vulnerability of critical infrastructure and high-density value assets including direct and indirect damage, (ii) the assessment and reliability of urban flood defences including the use of geophysical methods and remote sensing techniques and (iii) concepts and technologies for upgrading weak links in flood defences as well as construction technologies for flood proofing buildings and infrastructure networks to increase the flood resilience of the urban system. The primary impact of FloodProBE in advancing knowledge in these areas is an increase in the cost-effectiveness (i.e. performance) of new and existing flood protection structures and flood resilience measures.

An agent-based model of flood risk and insurance

NARCIS (Netherlands)

Dubbelboer, J.; Nikolic, I.; Jenkins, K.; Hall, J

2017-01-01

Flood risk emerges from the dynamic interaction between natural hazards and human vulnerability. Methods for the quantification of flood risk are well established, but tend to deal with human and economic vulnerability as being static or changing with an exogenously defined trend. In this paper

Challenges to social capacity building in flood-affected areas of southern Poland

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Działek, J.; Biernacki, W.; Bokwa, A.

2013-10-01

Various aspects of beliefs, behaviour and expectations of at-risk populations were analysed in four case study localities in southern Poland that were affected by flooding in 1997 and 2001. They represent localities of different sizes and are characterised by different paths of historical development. Two of them are deep-rooted communities with dense, strong family and neighbourhood ties, while the other two experienced an almost total replacement of their population due to decisions taken after World War II and still suffer from less developed social networks. Historical events also resulted in the disruption of local memories of flooding and transmission of knowledge about natural hazards. A questionnaire survey was conducted in late autumn 2006, followed by structured telephone interviews and focus group interviews in spring 2008. The results of the survey and interviews were analysed with reference to the social capacity framework and its five dimensions: knowledge, motivational, network, economic and governance capacities. Network capacities, that is resources of bonding and bridging social capital, were considered a key notion when analysing and interpreting the results. The differences in the local resources and abilities available in each of the localities to prepare a response to natural hazards were revealed. Consequently, challenges faced in the process of building and strengthening social capacity were identified as well as ways to address these challenges. It was concluded that there are general trends and tendencies that need to be considered in risk management strategies, however the different starting points of each case study community calls for different means and approaches, as well as producing somewhat different expected outcomes.

FLOOD CHARACTERISTICS AND MANAGEMENT ADAPTATIONS ...

African Journals Online (AJOL)

Dr Osondu

2011-10-26

Oct 26, 2011 ... Ethiopian Journal of Environmental Studies and Management Vol. ... people are estimated to be at such risk by 2080 .... SCS-CN method is based on the water balance .... and psychological burden of flood hazard often fall.

Dynamic model of forest area on flood zone of Padang City, West Sumatra Province-Indonesia

Science.gov (United States)

Dewata, Indang; Iswandi, U.

2018-05-01

The flood disaster has caused many harm to human life, and the change of watershed characteristic is one of the factors causing the flood disaster. The increase of deforestation due to the increase of water causes the occurrence of flood disaster in the rainy season. The research objective was to develop a dynamic model of forest on flood hazard zone using powersim 10.1. In model development, there are three scenarios: optimistic, moderate, and pessimistic. The study shows that in Padang there are about 13 percent of high flood hazard zones. Deforestation of 4.5 percent/year is one cause that may increased the flooding intensity in Padang. There will be 14 percent of total forest area when management policy of forest absence in 2050.

Creating a Flood Risk Index to Improve Community Resilience

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Klima, K.; El Gammal, L.

2017-12-01

While flood risk reduction is an existent discourse and agenda in policy and insurance, vulnerabilities vary between communities; some communities may have aging infrastructure, or an older/poorer population less able to absorb a flood, putting them at increased risk from the hazards. As a result, some are considering environmental justice aspects of flood risk reduction. To date, catastrophe models have focused on creating floodmaps (e.g., NOAA's Sea Level Rise Viewer, Climate Central's Surging Seas), or on linking hydrological models to economic loss models (e.g., HEC-RAS + HAZUS). However, this approach may be highly inequitable between areas of different income (as well as other demographics). Some have begun work on combining hydrology with vulnerability information (e.g., USACE's North Atlantic Comprehensive Coastal Study). To our knowledge, no one has tried to adapt the more advanced known heat risk theory to water risk by combining hydrology information (e.g., HEC-RAS, floodplain maps) with the social vulnerability (e.g., Cutter et al.) of the residents. This project will create a method to combine water hazard data with a derived water vulnerability index to help a community understand their current and future water risk. We will use the case study area of Pittsburgh, PA, which faces severe precipitation and riverine flooding hazards. Building on present literature of factors influencing water vulnerability contextualized to the Pittsburgh region, we will identify, quantify, and map the top factors impacting water vulnerability. We will combine these with flood maps to identify the geospatial distribution of water risk. This work will allow policy makers to identify location-specific aspects of water vulnerability and risk in any community, thus promoting environmental justice. It is possible that this type of original research would create maps of relative water risk that may prove as understandable to the general public as other flood maps, and may also

Assessment and Adaptation to Climate Change-Related Floods Risks

NARCIS (Netherlands)

Jongman, B.; Winsemius, H.C.; Fraser, S.; Muis, S.; Ward, P.J.

2018-01-01

The flooding of rivers and coastlines is the most frequent and damaging of all natural hazards. Between 1980 and 2016, total direct damages exceeded $1.6 trillion, and at least 225,000 people lost their lives. Recent events causing major economic losses include the 2011 river flooding in Thailand

Assessment of flood risk in Tokyo metropolitan area

Science.gov (United States)

Hirano, J.; Dairaku, K.

2013-12-01

Flood is one of the most significant natural hazards in Japan. The Tokyo metropolitan area has been affected by several large flood disasters. Therefore, investigating potential flood risk in Tokyo metropolitan area is important for development of adaptation strategy for future climate change. We aim to develop a method for evaluating flood risk in Tokyo Metropolitan area by considering effect of historical land use and land cover change, socio-economic change, and climatic change. Ministry of land, infrastructure, transport and tourism in Japan published 'Statistics of flood', which contains data for flood causes, number of damaged houses, area of wetted surface, and total amount of damage for each flood at small municipal level. By using these flood data, we estimated damage by inundation inside a levee for each prefecture based on a statistical method. On the basis of estimated damage, we developed flood risk curves in the Tokyo metropolitan area, representing relationship between damage and exceedance probability of flood for the period 1976-2008 for each prefecture. Based on the flood risk curve, we attempted evaluate potential flood risk in the Tokyo metropolitan area and clarify the cause for regional difference of flood risk. By analyzing flood risk curves, we found out regional differences of flood risk. We identified high flood risk in Tokyo and Saitama prefecture. On the other hand, flood risk was relatively low in Ibaraki and Chiba prefecture. We found that these regional differences of flood risk can be attributed to spatial distribution of entire property value and ratio of damaged housing units in each prefecture.We also attempted to evaluate influence of climate change on potential flood risk by considering variation of precipitation amount and precipitation intensity in the Tokyo metropolitan area. Results shows that we can evaluate potential impact of precipitation change on flood risk with high accuracy by using our methodology. Acknowledgments

Thirty Years Later: Reflections of the Big Thompson Flood, Colorado, 1976 to 2006

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Jarrett, R. D.; Costa, J. E.; Brunstein, F. C.; Quesenberry, C. A.; Vandas, S. J.; Capesius, J. P.; O'Neill, G. B.

2006-12-01

Thirty years ago, over 300 mm of rain fell in about 4 to 6 hours in the middle reaches of the Big Thompson River Basin during the devastating flash flood on July 31, 1976. The rainstorm produced flood discharges that exceeded 40 m3/s/km2. A peak discharge of 883 m3/s was estimated at the Big Thompson River near Drake streamflow-gaging station. The raging waters left 144 people dead, 250 injured, and over 800 people were evacuated by helicopter. Four-hundred eighteen homes and businesses were destroyed, as well as 438 automobiles, and damage to infrastructure left the canyon reachable only via helicopter. Total damage was estimated in excess of $116 million (2006 dollars). Natural hazards similar to the Big Thompson flood are rare, but the probability of a similar event hitting the Front Range, other parts of Colorado, or other parts of the Nation is real. Although much smaller in scale than the Big Thompson flood, several flash floods have happened during the monsoon in early July 2006 in the Colorado foothills that reemphasized the hazards associated with flash flooding. The U.S. Geological Survey (USGS) conducts flood research to help understand and predict the magnitude and likelihood of large streamflow events such as the Big Thompson flood. A summary of hydrologic conditions of the 1976 flood, what the 1976 flood can teach us about flash floods, a description of some of the advances in USGS flood science as a consequence of this disaster, and lessons that we learned to help reduce loss of life from this extraordinary flash flood are discussed. In the 30 years since the Big Thompson flood, there have been important advances in streamflow monitoring and flood warning. The National Weather Service (NWS) NEXRAD radar allows real-time monitoring of precipitation in most places in the United States. The USGS currently (2006) operates about 7,250 real-time streamflow-gaging stations in the United States that are monitored by the USGS, the NWS, and emergency managers

Climate Change Impacts on Flood risk in Urban Areas due to Combined Effects of Extreme Precipitation and Sea Surges

DEFF Research Database (Denmark)

Larsen, A. N.; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten

Climate change will impact the hydrological cycle greatly and lead to increases in flood hazards due to both pluvial and fluvial floods as well as sea surges in many regions. The impacts of the individual effects are analysed for a catchment in Greater Copenhagen. Based on both the present...... surges. Presently the most important hazard is due to extreme precipitation. However, due to climate change impacts the future most important hazard is due to sea surges. The increase in probability of floods is substantial over a 70 year horizon and actions must be taken to decrease either the hazards...

NATURAL HAZARD ASSESSMENT OF SW MYANMAR - A CONTRIBUTION OF REMOTE SENSING AND GIS METHODS TO THE DETECTION OF AREAS VULNERABLE TO EARTHQUAKES AND TSUNAMI / CYCLONE FLOODING

Directory of Open Access Journals (Sweden)

George Pararas-Carayannis

2009-01-01

Full Text Available Myanmar, formerly Burma, is vulnerable to several natural hazards, such as earthquakes, cyclones, floods, tsunamis and landslides. The present study focuses on geomorphologic and geologic investigations of the south-western region of the country, based on satellite data (Shuttle Radar Topography Mission-SRTM, MODIS and LANDSAT. The main objective is to detect areas vulnerable to inundation by tsunami waves and cyclone surges. Since the region is also vulnerable to earthquake hazards, it is also important to identify seismotectonic patterns, the location of major active faults, and local site conditions that may enhance ground motions and earthquake intensities. As illustrated by this study, linear, topographic features related to subsurface tectonic features become clearly visible on SRTM-derived morphometric maps and on LANDSAT imagery. The GIS integrated evaluation of LANDSAT and SRTM data helps identify areas most susceptible to flooding and inundation by tsunamis and storm surges. Additionally, land elevation maps help identify sites greater than 10 m in elevation height, that would be suitable for the building of protective tsunami/cyclone shelters.

Flood extent and water level estimation from SAR using data-model integration

Science.gov (United States)

Ajadi, O. A.; Meyer, F. J.

2017-12-01

Synthetic Aperture Radar (SAR) images have long been recognized as a valuable data source for flood mapping. Compared to other sources, SAR's weather and illumination independence and large area coverage at high spatial resolution supports reliable, frequent, and detailed observations of developing flood events. Accordingly, SAR has the potential to greatly aid in the near real-time monitoring of natural hazards, such as flood detection, if combined with automated image processing. This research works towards increasing the reliability and temporal sampling of SAR-derived flood hazard information by integrating information from multiple SAR sensors and SAR modalities (images and Interferometric SAR (InSAR) coherence) and by combining SAR-derived change detection information with hydrologic and hydraulic flood forecast models. First, the combination of multi-temporal SAR intensity images and coherence information for generating flood extent maps is introduced. The application of least-squares estimation integrates flood information from multiple SAR sensors, thus increasing the temporal sampling. SAR-based flood extent information will be combined with a Digital Elevation Model (DEM) to reduce false alarms and to estimate water depth and flood volume. The SAR-based flood extent map is assimilated into the Hydrologic Engineering Center River Analysis System (Hec-RAS) model to aid in hydraulic model calibration. The developed technology is improving the accuracy of flood information by exploiting information from data and models. It also provides enhanced flood information to decision-makers supporting the response to flood extent and improving emergency relief efforts.

Urban flooding and Resilience: concepts and needs

Science.gov (United States)

Gourbesville, Ph.

2012-04-01

During the recent years, a growing interest for resilience has been expressed in the natural disaster mitigation area and especially in the flood related events. The European Union, under the Seventh Framework Programme (FP7), has initiated several research initiatives in order to explore this concept especially for the urban environments. Under urban resilience is underlined the ability of system potentially exposed to hazard to resist, respond, recover and reflect up to stage which is enough to preserve level of functioning and structure. Urban system can be resilient to lot of different hazards. Urban resilience is defined as the degree to which cities are able to tolerate some disturbance before reorganizing around a new set of structures and processes (Holling 1973, De Bruijn 2005). The United Nation's International strategy for Disaster Reductions has defined resilience as "the capacity of a system, community or society potentially exposed to hazards to adapt, by resisting or changing in order to reach and maintain an acceptable level of functioning and structure. This is determined by the degree to which the social system is capable of organizing itself to increase this capacity for learning from past disasters for better future protection and to improve risk reduction measures."(UN/ISDR 2004). According to that, system should be able to accept the hazard and be able to recover up to condition that provides acceptable operational level of city structure and population during and after hazard event. Main elements of urban system are built environment and population. Physical characteristic of built environment and social characteristic of population have to be examined in order to evaluate resilience. Therefore presenting methodology for assessing flood resilience in urban areas has to be one of the focal points for the exposed cities. Strategies under flood management planning related to resilience of urban systems are usually regarding controlling runoff

Urban micro-scale flood risk estimation with parsimonious hydraulic modelling and census data

Directory of Open Access Journals (Sweden)

C. Arrighi

2013-05-01

Full Text Available The adoption of 2007/60/EC Directive requires European countries to implement flood hazard and flood risk maps by the end of 2013. Flood risk is the product of flood hazard, vulnerability and exposure, all three to be estimated with comparable level of accuracy. The route to flood risk assessment is consequently much more than hydraulic modelling of inundation, that is hazard mapping. While hazard maps have already been implemented in many countries, quantitative damage and risk maps are still at a preliminary level. A parsimonious quasi-2-D hydraulic model is here adopted, having many advantages in terms of easy set-up. It is here evaluated as being accurate in flood depth estimation in urban areas with a high-resolution and up-to-date Digital Surface Model (DSM. The accuracy, estimated by comparison with marble-plate records of a historic flood in the city of Florence, is characterized in the downtown's most flooded area by a bias of a very few centimetres and a determination coefficient of 0.73. The average risk is found to be about 14 € m−2 yr−1, corresponding to about 8.3% of residents' income. The spatial distribution of estimated risk highlights a complex interaction between the flood pattern and the building characteristics. As a final example application, the estimated risk values have been used to compare different retrofitting measures. Proceeding through the risk estimation steps, a new micro-scale potential damage assessment method is proposed. This is based on the georeferenced census system as the optimal compromise between spatial detail and open availability of socio-economic data. The results of flood risk assessment at the census section scale resolve most of the risk spatial variability, and they can be easily aggregated to whatever upper scale is needed given that they are geographically defined as contiguous polygons. Damage is calculated through stage–damage curves, starting from census data on building type and

Time-dependent reliability analysis of flood defences

International Nuclear Information System (INIS)

Buijs, F.A.; Hall, J.W.; Sayers, P.B.; Gelder, P.H.A.J.M. van

2009-01-01

This paper describes the underlying theory and a practical process for establishing time-dependent reliability models for components in a realistic and complex flood defence system. Though time-dependent reliability models have been applied frequently in, for example, the offshore, structural safety and nuclear industry, application in the safety-critical field of flood defence has to date been limited. The modelling methodology involves identifying relevant variables and processes, characterisation of those processes in appropriate mathematical terms, numerical implementation, parameter estimation and prediction. A combination of stochastic, hierarchical and parametric processes is employed. The approach is demonstrated for selected deterioration mechanisms in the context of a flood defence system. The paper demonstrates that this structured methodology enables the definition of credible statistical models for time-dependence of flood defences in data scarce situations. In the application of those models one of the main findings is that the time variability in the deterioration process tends to be governed the time-dependence of one or a small number of critical attributes. It is demonstrated how the need for further data collection depends upon the relevance of the time-dependence in the performance of the flood defence system.

Geologic hazards in the region of the Hurricane fault

Science.gov (United States)

Lund, W.R.

1997-01-01

Complex geology and variable topography along the 250-kilometer-long Hurricane fault in northwestern Arizona and southwestern Utah combine to create natural conditions that can present a potential danger to life and property. Geologic hazards are of particular concern in southwestern Utah, where the St. George Basin and Interstate-15 corridor north to Cedar City are one of Utah's fastest growing areas. Lying directly west of the Hurricane fault and within the Basin and Range - Colorado Plateau transition zone, this region exhibits geologic characteristics of both physiographic provinces. Long, potentially active, normal-slip faults displace a generally continuous stratigraphic section of mostly east-dipping late Paleozoic to Cretaceous sedimentary rocks unconformably overlain by Tertiary to Holocene sedimentary and igneous rocks and unconsolidated basin-fill deposits. Geologic hazards (exclusive of earthquake hazards) of principal concern in the region include problem soil and rock, landslides, shallow ground water, and flooding. Geologic materials susceptible to volumetric change, collapse, and subsidence in southwestern Utah include; expansive soil and rock, collapse-prone soil, gypsum and gypsiferous soil, soluble carbonate rocks, and soil and rock subject to piping and other ground collapse. Expansive soil and rock are widespread throughout the region. The Petrified Forest Member of the Chinle Formation is especially prone to large volume changes with variations in moisture content. Collapse-prone soils are common in areas of Cedar City underlain by alluvial-fan material derived from the Moenkopi and Chinle Formations in the nearby Hurricane Cliffs. Gypsiferous soil and rock are subject to dissolution which can damage foundations and create sinkholes. The principal formations in the region affected by dissolution of carbonate are the Kaibab and Toroweap Formations; both formations have developed sinkholes where crossed by perennial streams. Soil piping is

ENSO impacts on flood risk at the global scale

Science.gov (United States)

Ward, Philip; Dettinger, Michael; Jongman, Brenden; Kummu, Matti; Winsemius, Hessel

2014-05-01

We present the impacts of El Niño Southern Oscillation (ENSO) on society and the economy, via relationships between ENSO and the hydrological cycle. We also discuss ways in which this knowledge can be used in disaster risk management and risk reduction. This contribution provides the most recent results of an ongoing 4-year collaborative research initiative to assess and map the impacts of large scale interannual climate variability on flood hazard and risk at the global scale. We have examined anomalies in flood risk between ENSO phases, whereby flood risk is expressed in terms of indicators such as: annual expected damage; annual expected affected population; annual expected affected Gross Domestic Product (GDP). We show that large anomalies in flood risk occur during El Niño or La Niña years in basins covering large parts of the Earth's surface. These anomalies reach statistical significance river basins covering almost two-thirds of the Earth's surface. Particularly strong anomalies exist in southern Africa, parts of western Africa, Australia, parts of Central Eurasia (especially for El Niño), the western USA (especially La Niña anomalies), and parts of South America. We relate these anomalies to possible causal relationships between ENSO and flood hazard, using both modelled and observed data on flood occurrence and extremity. The implications for flood risk management are many-fold. In those regions where disaster risk is strongly influenced by ENSO, the potential predictably of ENSO could be used to develop probabilistic flood risk projections with lead times up to several seasons. Such data could be used by the insurance industry in managing risk portfolios and by multinational companies for assessing the robustness of their supply chains to potential flood-related interruptions. Seasonal forecasts of ENSO influence of peak flows could also allow for improved flood early warning and regulation by dam operators, which could also reduce overall risks

Hydrochemical aspects of the Aue pit flooding

International Nuclear Information System (INIS)

Meyer, J.; Jenk, U.; Schuppan, W.; Knappik, R.

1998-01-01

WISMUT is conducting controlled flooding of underground mines at the Schlema-Alberoda and Poehla sites. Flooding of the Poehla mine lasted from January 1992 through September 1995. Flooding at the Niederschlema-Alberoda site began in July 1990 and will continue to approximately 2002. In mid-1998 the flood level had reached the - 420 m level which is about 1,400 m above the lowest mine level. Only ground waters with low mineral and pollutant content are used for flooding purposes. Typically, the flooding process results in elevated levels of mineral salts and of uranium, radium, arsenic, iron, and manganese in flooding waters. However, the mobilised part of these contaminants represents only a small fraction of potential concentrations contained in the surrounding rock. Geochemical and hydrochemical conditions at both mines are characterised by the presence of carbonate buffers and by neutral pH and intermediate to low Eh. Decrease due to oxidation of sulphides in the long term is unlikely. Environmentally relevant metals in flooding waters may be dissolved, colloidal, or suspended solids with uranium present as uranyl carbonate complexes. Intensity of mobilisation is primarily a function of kinetic processes. Post flooding conditions at the Poehla subsite exhibit specific hydrochemical phenomena such as extremely reduced SO 4 concentrations and an increase in Ra concentrations over time. Continued flood monitoring will provide the basis for more in-depth interpretation and prognosis of contaminant mobilisation. Current investigations focus on technically feasible in situ control of mine flooding at the Schlema-Alberoda site to reduce contaminant mobilisation. At both sites water treatment plants are either on stream or under construction. (orig.)

Flood Hazard Mapping : Uncertainty and its Value in the Decision-making Process

NARCIS (Netherlands)

Mukolwe, M.M.

2016-01-01

Computers are increasingly used in the simulation of natural phenomena such as floods. However, these simulations are based on numerical approximations of equations formalizing our conceptual understanding of flood flows. Thus, model results are intrinsically subject to uncertainty and the use of

Flood Hazard Mapping: Uncertainty and its Value in the Decision-making Process

NARCIS (Netherlands)

Mukolwe, M.M.

2016-01-01

Computers are increasingly used in the simulation of natural phenomena such as floods. However, these simulations are based on numerical approximations of equations formalizing our conceptual understanding of flood flows. Thus, model results are intrinsically subject to uncertainty and the use of

Assessing Natural Hazard Vulnerability Through Marmara Region Using GIS

Science.gov (United States)

Sabuncu, A.; Garagon Dogru, A.; Ozener, H.

2013-12-01

Natural hazards are natural phenomenon occured in the Earth's system that include geological and meteorological events such as earthquakes, floods, landslides, droughts, fires and tsunamis. The metropolitan cities are vulnerable to natural hazards due to their population densities, industrial facilities and proporties. The urban layout of the megacities are complex since industrial facilities are interference with residential area. The Marmara region is placed in North-western Turkey suffered from natural hazards (earthquakes, floods etc.) for years. After 1999 Kocaeli and Duzce earthquakes and 2009 Istanbul flash floods, dramatic number of casualities and economic losses were reported by the authorities. Geographic information systems (GIS) have substantial capacity in order to develop natural disaster management. As these systems provide more efficient and reliable analysis and evaluation of the data in the management, and also convenient and better solutions for the decision making before during and after the natural hazards. The Earth science data and socio-economic data can be integrated into a GIS as different layers. Additionally, satellite data are used to understand the changes pre and post the natural hazards. GIS is a powerful software for the combination of different type of digital data. A natural hazard database for the Marmara region provides all different types of digital data to the users. All proper data collection processing and analysing are critical to evaluate and identify hazards. The natural hazard database allows users to monitor, analyze and query past and recent disasters in the Marmara Region. The long term aim of this study is to develop geodatabase and identify the natural hazard vulnerabilities of the metropolitan cities.

A critical analysis of hazard resilience measures within sustainability assessment frameworks

International Nuclear Information System (INIS)

Matthews, Elizabeth C.; Sattler, Meredith; Friedland, Carol J.

2014-01-01

Today, numerous sustainability assessment frameworks (SAFs) exist to guide designers in achieving sustainable performance in the design of structures and communities. SAFs are beneficial in educating users and are useful tools for incorporating sustainability strategies into planning, design, and construction; however, there is currently a substantial gap in the ability of existing SAFs to incorporate hazard resistance and hazard mitigation in the broader context of sustainable design. This paper analyzes the incorporation of hazard resistant design and hazard mitigation strategies within SAFs via a multi-level analysis of eleven SAFs. The SAFs analyzed range in scale of application (i.e. building, site, community). Three levels of analysis are presented: (1) macro-level analysis comparing the number of measures strictly addressing resilience versus sustainability, (2) meso-level analysis of the coverage of types of hazards within SAFs (e.g. flood, fire), and (3) micro-level analysis of SAF measures connected to flood-related hazard resilience. The results demonstrate that hazard resistance and hazard mitigation do not figure prominently in the intent of SAFs and that weaknesses in resilience coverage exist that have the potential to lead to the design of structures and communities that are still highly vulnerable to the impacts of extreme events. - Highlights: • Sustainability assessment frameworks (SAFs) were analyzed for resilience coverage • Hazard resistance and mitigation do not figure prominently in the intent of SAFs • Approximately 75% of SAFs analyzed address three or fewer hazards • Lack of economic measures within SAFs could impact resilience and sustainability • Resilience measures for flood hazards are not consistently included in SAFs

A critical analysis of hazard resilience measures within sustainability assessment frameworks

Energy Technology Data Exchange (ETDEWEB)

Matthews, Elizabeth C., E-mail: echiso1@lsu.edu [Louisiana State University, Baton Rouge, LA (United States); Sattler, Meredith, E-mail: msattler@lsu.edu [School of Architecture, Louisiana State University, Baton Rouge, LA (United States); Friedland, Carol J., E-mail: friedland@lsu.edu [Bert S. Turner Department of Construction Management, Louisiana State University, Baton Rouge, LA (United States)

2014-11-15

Today, numerous sustainability assessment frameworks (SAFs) exist to guide designers in achieving sustainable performance in the design of structures and communities. SAFs are beneficial in educating users and are useful tools for incorporating sustainability strategies into planning, design, and construction; however, there is currently a substantial gap in the ability of existing SAFs to incorporate hazard resistance and hazard mitigation in the broader context of sustainable design. This paper analyzes the incorporation of hazard resistant design and hazard mitigation strategies within SAFs via a multi-level analysis of eleven SAFs. The SAFs analyzed range in scale of application (i.e. building, site, community). Three levels of analysis are presented: (1) macro-level analysis comparing the number of measures strictly addressing resilience versus sustainability, (2) meso-level analysis of the coverage of types of hazards within SAFs (e.g. flood, fire), and (3) micro-level analysis of SAF measures connected to flood-related hazard resilience. The results demonstrate that hazard resistance and hazard mitigation do not figure prominently in the intent of SAFs and that weaknesses in resilience coverage exist that have the potential to lead to the design of structures and communities that are still highly vulnerable to the impacts of extreme events. - Highlights: • Sustainability assessment frameworks (SAFs) were analyzed for resilience coverage • Hazard resistance and mitigation do not figure prominently in the intent of SAFs • Approximately 75% of SAFs analyzed address three or fewer hazards • Lack of economic measures within SAFs could impact resilience and sustainability • Resilience measures for flood hazards are not consistently included in SAFs.

Natural phenomena hazards, Hanford Site, Washington

International Nuclear Information System (INIS)

Conrads, T.J.

1998-01-01

This document presents the natural phenomena hazard loads for use in implementing DOE Order 5480.28, Natural Phenomena Hazards Mitigation, and supports development of double-shell tank systems specifications at the Hanford Site in south-central Washington State. The natural phenomena covered are seismic, flood, wind, volcanic ash, lightning, snow, temperature, solar radiation, suspended sediment, and relative humidity

An Integrated Modelling Framework to Assess Flood Risk under Urban Development and Changing Climate

DEFF Research Database (Denmark)

Löwe, Roland; Urich, Christian; Sto Domingo, Nina

Flood risk in cities is strongly affected by the development of the city itself. Many studies focus on changes in the flood hazard as a result of, for example, changed degrees of sealing in the catchment or climatic changes. However, urban developments in flood prone areas can affect the exposure...... to the hazard and thus have large impacts on flood risk. Different urban socio-economic development scenarios, rainfall inputs and options for the mitigation of flood risk, quickly lead to a large number of scenarios that need to be considered in the planning of the development of a city. This calls...... for automated analyses that allow the planner to quickly identify if, when and how infrastructure should be modified. Such analysis, which accounts for the two-way interactions between city development and flood risk, is possible only to a limited extent in existing tools. We have developed a software framework...

Visualization of the Impact of the Catastrophic Flooding Events

DEFF Research Database (Denmark)

Mioc, Darka; Anton, François; Moreri, K. K.

maps. This can greatly help decision makers with the emergency measures and mitigation in most of the cases. In this article, we present a case study about mapping of flood risks due to a dam burst showing risk maps of flood hazards and available emergency facilities and their significance for risk...... prevention and mitigation....

44 CFR 59.22 - Prerequisites for the sale of flood insurance.

Science.gov (United States)

2010-10-01

... AGENCY, DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program... public inspection and furnish upon request, for the determination of applicable flood insurance risk... Federal, State, and local agencies and private firms which undertake to study, survey, map, and identify...

Climate change impact on flood hazard

Directory of Open Access Journals (Sweden)

M. Brilly

2014-09-01

Full Text Available Climate changes have a high impact on river discharges and therefore on floods. There are a few different methods we can use to predict discharge changes in the future. In this paper we used the complex HBV model for the Vipava River and simple correlation between discharge and precipitation data for the Soča River. The discharge prediction is based on the E-OBS precipitation data for three future time periods (2011–2040, 2041–2070 and 2071–2100. Estimated discharges for those three future periods are presented for both rivers. But a special situation occurs at the confluence where the two rivers with rather different catchments unite, and this requires an additional probability analysis.

Flood inundation modeling and hazard mapping under uncertainty in the Sungai Johor basin, Malaysia

NARCIS (Netherlands)

Md. Ali, A.

2018-01-01

Flooding can have devastating impacts on people’s livelihood, economy and the environment. An important instrument in flood management is floodplain maps, which assist land planners and local authorities in identifying flood-prone areas, and provide useful information for rescue and relief agencies

Health impacts of floods.

Science.gov (United States)

Du, Weiwei; FitzGerald, Gerard Joseph; Clark, Michele; Hou, Xiang-Yu

2010-01-01

Floods are the most common hazard to cause disasters and have led to extensive morbidity and mortality throughout the world. The impact of floods on the human community is related directly to the location and topography of the area, as well as human demographics and characteristics of the built environment. The aim of this study is to identify the health impacts of disasters and the underlying causes of health impacts associated with floods. A conceptual framework is developed that may assist with the development of a rational and comprehensive approach to prevention, mitigation, and management. This study involved an extensive literature review that located >500 references, which were analyzed to identify common themes, findings, and expert views. The findings then were distilled into common themes. The health impacts of floods are wide ranging, and depend on a number of factors. However, the health impacts of a particular flood are specific to the particular context. The immediate health impacts of floods include drowning, injuries, hypothermia, and animal bites. Health risks also are associated with the evacuation of patients, loss of health workers, and loss of health infrastructure including essential drugs and supplies. In the medium-term, infected wounds, complications of injury, poisoning, poor mental health, communicable diseases, and starvation are indirect effects of flooding. In the long-term, chronic disease, disability, poor mental health, and poverty-related diseases including malnutrition are the potential legacy. This article proposes a structured approach to the classification of the health impacts of floods and a conceptual framework that demonstrates the relationships between floods and the direct and indirect health consequences.

Flooding hazards from sea extremes and subsidence

DEFF Research Database (Denmark)

Sørensen, Carlo; Vognsen, Karsten; Broge, Niels

2015-01-01

of tide gauge records, statistics that allow also for projections of SLR, meteorological variability, and extremes with a very low probability of occurrence are provided. Land movement is researched with a focus on short term surface height variability in the groundwater-ocean interface that, together...... with longer term processes, may cause substantial subsidence and impact future water management and adaptation strategies in flood prone coastal areas. Field studies’ results from repeated precise levelling, GPS setups, and ocean and groundwater level monitoring in Thyborøn and Aarhus are integrated...

May flood-poor periods be more dangerous than flood-rich periods?

Science.gov (United States)

Salinas, Jose Luis; Di Baldassarre, Giuliano; Viglione, Alberto; Kuil, Linda; Bloeschl, Guenter

2014-05-01

River floods are among the most devastating natural hazards experienced by populations that, since the earliest recorded civilisations, have settled in floodplains because they offer favourable conditions for trade, agriculture, and economic development. The occurrence of a flood may cause loss of lives and tremendous economic damages and, therefore, is rightly seen as a very negative event by the communities involved. Occurrence of many floods in a row is, of course, even more frustrating and is rightly considered a unbearable calamity. Unfortunately, the occurrence of many floods in a limited number of consecutive years is not unusual. In many places in the world, it has been observed that extreme floods do not arrive randomly but cluster in time into flood-poor and flood-rich periods consistent with the Hurst effect. If this is the case, when are the people more in danger? When should people be more scared? In flood-poor or flood-rich periods? In this work, a Socio-Hydrology model (Di Baldassarre et al., 2013; Viglione et al., 2014) is used to show that, maybe counter-intuitively, flood-poor periods may be more dangerous than flood-rich periods. The model is a conceptualisation of a hypothetical setting of a city at a river where a community evolves, making choices between flood management options on the floodplain. The most important feedbacks between the economic, political, technological and hydrological processes of the evolution of that community are represented in the model. In particular, the model also accounts in a dynamic way for the evolution of the the community awareness to flood risk. Occurrence of floods tends to increase peoples' recognition that their property is in an area that is potentially at risk of flooding, both at the scales of individuals and communities, which is one of the main reasons why flood coping actions are taken. It is shown through examples that frequent flood events may result in moderate damages because they ensure that the