On the reliable use of satellite-derived surface water products for global flood monitoring

NASA Astrophysics Data System (ADS)

Hirpa, F. A.; Revilla-Romero, B.; Thielen, J.; Salamon, P.; Brakenridge, R.; Pappenberger, F.; de Groeve, T.

2015-12-01

Early flood warning and real-time monitoring systems play a key role in flood risk reduction and disaster response management. To this end, real-time flood forecasting and satellite-based detection systems have been developed at global scale. However, due to the limited availability of up-to-date ground observations, the reliability of these systems for real-time applications have not been assessed in large parts of the globe. In this study, we performed comparative evaluations of the commonly used satellite-based global flood detections and operational flood forecasting system using 10 major flood cases reported over three years (2012-2014). Specially, we assessed the flood detection capabilities of the near real-time global flood maps from the Global Flood Detection System (GFDS), and from the Moderate Resolution Imaging Spectroradiometer (MODIS), and the operational forecasts from the Global Flood Awareness System (GloFAS) for the major flood events recorded in global flood databases. We present the evaluation results of the global flood detection and forecasting systems in terms of correctly indicating the reported flood events and highlight the exiting limitations of each system. Finally, we propose possible ways forward to improve the reliability of large scale flood monitoring tools.

Probabilistic flood extent estimates from social media flood observations

NASA Astrophysics Data System (ADS)

Brouwer, Tom; Eilander, Dirk; van Loenen, Arnejan; Booij, Martijn J.; Wijnberg, Kathelijne M.; Verkade, Jan S.; Wagemaker, Jurjen

2017-05-01

The increasing number and severity of floods, driven by phenomena such as urbanization, deforestation, subsidence and climate change, create a growing need for accurate and timely flood maps. In this paper we present and evaluate a method to create deterministic and probabilistic flood maps from Twitter messages that mention locations of flooding. A deterministic flood map created for the December 2015 flood in the city of York (UK) showed good performance (F(2) = 0.69; a statistic ranging from 0 to 1, with 1 expressing a perfect fit with validation data). The probabilistic flood maps we created showed that, in the York case study, the uncertainty in flood extent was mainly induced by errors in the precise locations of flood observations as derived from Twitter data. Errors in the terrain elevation data or in the parameters of the applied algorithm contributed less to flood extent uncertainty. Although these maps tended to overestimate the actual probability of flooding, they gave a reasonable representation of flood extent uncertainty in the area. This study illustrates that inherently uncertain data from social media can be used to derive information about flooding.

High-magnitude flooding across Britain since AD 1750

NASA Astrophysics Data System (ADS)

Macdonald, Neil; Sangster, Heather

2017-03-01

The last decade has witnessed severe flooding across much of the globe, but have these floods really been exceptional? Globally, relatively few instrumental river flow series extend beyond 50 years, with short records presenting significant challenges in determining flood risk from high-magnitude floods. A perceived increase in extreme floods in recent years has decreased public confidence in conventional flood risk estimates; the results affect society (insurance costs), individuals (personal vulnerability) and companies (e.g. water resource managers). Here, we show how historical records from Britain have improved understanding of high-magnitude floods, by examining past spatial and temporal variability. The findings identify that whilst recent floods are notable, several comparable periods of increased flooding are identifiable historically, with periods of greater frequency (flood-rich periods). Statistically significant relationships between the British flood index, the Atlantic Meridional Oscillation and the North Atlantic Oscillation Index are identified. The use of historical records identifies that the largest floods often transcend single catchments affecting regions and that the current flood-rich period is not unprecedented.

Flood Insurance in Canada: Implications for Flood Management and Residential Vulnerability to Flood Hazards

NASA Astrophysics Data System (ADS)

Oulahen, Greg

2015-03-01

Insurance coverage of damage caused by overland flooding is currently not available to Canadian homeowners. As flood disaster losses and water damage claims both trend upward, insurers in Canada are considering offering residential flood coverage in order to properly underwrite the risk and extend their business. If private flood insurance is introduced in Canada, it will have implications for the current regime of public flood management and for residential vulnerability to flood hazards. This paper engages many of the competing issues surrounding the privatization of flood risk by addressing questions about whether flood insurance can be an effective tool in limiting exposure to the hazard and how it would exacerbate already unequal vulnerability. A case study investigates willingness to pay for flood insurance among residents in Metro Vancouver and how attitudes about insurance relate to other factors that determine residential vulnerability to flood hazards. Findings indicate that demand for flood insurance is part of a complex, dialectical set of determinants of vulnerability.

Flood information for flood-plain planning

USGS Publications Warehouse

Bue, Conrad D.

1967-01-01

Floods are natural and normal phenomena. They are catastrophic simply because man occupies the flood plain, the highwater channel of a river. Man occupies flood plains because it is convenient and profitable to do so, but he must purchase his occupancy at a price-either sustain flood damage, or provide flood-control facilities. Although large sums of money have been, and are being, spent for flood control, flood damage continues to mount. However, neither complete flood control nor abandonment of the flood plain is practicable. Flood plains are a valuable resource and will continue to be occupied, but the nature and degree of occupancy should be compatible with the risk involved and with the degree of protection that is practicable to provide. It is primarily to meet the needs for defining the risk that the flood-inundation maps of the U.S. Geological Survey are prepared.

Development of flood index by characterisation of flood hydrographs

NASA Astrophysics Data System (ADS)

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, Oc-gok Basin in Republic of Korea and the haor region of Bangladesh. Keywords: flood index, flood risk management, flood characteristics

Flood of August 2, 1972, in the Little Maquoketa River basin, Dubuque County, Iowa

USGS Publications Warehouse

Heinitz, Albert J.

1973-01-01

Flood-peak discharges at 12 sites, basin rainfall, a description of the 1972 flood, brief accounts of other major floods in the basin, maximum flood peaks in northeastern Iowa, selected flood-frequency data, and annual floods of record at 5 sites are given.

Flood Risk and Global Change: Future Prospects

NASA Astrophysics Data System (ADS)

Serra-Llobet, A.

2014-12-01

Global flood risk is increasing in response to population growth in flood-prone areas, human encroachment into natural flood paths (exacerbating flooding in areas formerly out of harm's way), and climate change (which alters variables driving floods). How will societies respond to and manage flood risk in coming decades? Analysis of flood policy evolution in the EU and US demonstrates that changes occurred in steps, in direct response to disasters. After the flood produced by the collapse of Tous Dam in 1982, Spain initiated a systematic assessment of areas of greatest flood risk and civil protection response. The devastating floods on the Elbe and elsewhere in central Europe in 2002 motivated adoption of the EU Floods Directive (2007), which requires member states to develop systematic flood risk maps (now due) and flood risk management plans (due in 2015). The flooding of New Orleans by Hurricane Katrina in 2005 resulted in a nationwide levee-safety assessment and improvements in communicating risk, but overall less fundamental change in US flood management than manifest in the EU since 2007. In the developing world, large (and increasing) concentrations of populations in low-lying floodplains, deltas, and coasts are increasingly vulnerable, and governments mostly ill-equipped to implement fundamental changes in land use to prevent future increases in exposure, nor to develop responses to the current threats. Even in the developed world, there is surprisingly little research on how well residents of flood-prone lands understand their true risk, especially when they are 'protected' by '100-year' levees. Looking ahead, researchers and decision makers should prioritize improvements in flood risk perception, river-basin-scale assessment of flood runoff processes (under current and future climate and land-use conditions) and flood management alternatives, and bridging the disconnect between national and international floodplain management policies and local land-use decisions.

What are the hydro-meteorological controls on flood characteristics?

NASA Astrophysics Data System (ADS)

Nied, Manuela; Schröter, Kai; Lüdtke, Stefan; Nguyen, Viet Dung; Merz, Bruno

2017-02-01

Flood events can be expressed by a variety of characteristics such as flood magnitude and extent, event duration or incurred loss. Flood estimation and management may benefit from understanding how the different flood characteristics relate to the hydrological catchment conditions preceding the event and to the meteorological conditions throughout the event. In this study, we therefore propose a methodology to investigate the hydro-meteorological controls on different flood characteristics, based on the simulation of the complete flood risk chain from the flood triggering precipitation event, through runoff generation in the catchment, flood routing and possible inundation in the river system and floodplains to flood loss. Conditional cumulative distribution functions and regression tree analysis delineate the seasonal varying flood processes and indicate that the effect of the hydrological pre-conditions, i.e. soil moisture patterns, and of the meteorological conditions, i.e. weather patterns, depends on the considered flood characteristic. The methodology is exemplified for the Elbe catchment. In this catchment, the length of the build-up period, the event duration and the number of gauges undergoing at least a 10-year flood are governed by weather patterns. The affected length and the number of gauges undergoing at least a 2-year flood are however governed by soil moisture patterns. In case of flood severity and loss, the controlling factor is less pronounced. Severity is slightly governed by soil moisture patterns whereas loss is slightly governed by weather patterns. The study highlights that flood magnitude and extent arise from different flood generation processes and concludes that soil moisture patterns as well as weather patterns are not only beneficial to inform on possible flood occurrence but also on the involved flood processes and resulting flood characteristics.

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

NASA Astrophysics Data System (ADS)

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.

Pluvial, urban flood mechanisms and characteristics - Assessment based on insurance claims

NASA Astrophysics Data System (ADS)

Sörensen, Johanna; Mobini, Shifteh

2017-12-01

Pluvial flooding is a problem in many cities and for city planning purpose the mechanisms behind pluvial flooding are of interest. Previous studies seldom use insurance claim data to analyse city scale characteristics that lead to flooding. In the present study, two long time series (∼20 years) of flood claims from property owners have been collected and analysed in detail to investigate the mechanisms and characteristics leading to urban flooding. The flood claim data come from the municipal water utility company and property owners with insurance that covers property loss from overland flooding, groundwater intrusion through basement walls and flooding from the drainage system. These data are used as a proxy for flood severity for several events in the Swedish city of Malmö. It is discussed which rainfall characteristics give most flooding and why some rainfall events do not lead to severe flooding, how city scale topography and sewerage system type influence spatial distribution of flood claims, and which impact high sea level has on flooding in Malmö. Three severe flood events are described in detail and compared with a number of smaller flood events. It was found that the main mechanisms and characteristics of flood extent and its spatial distribution in Malmö are intensity and spatial distribution of rainfall, distance to the main sewer system as well as overland flow paths, and type of drainage system, while high sea level has little impact on the flood extent. Finally, measures that could be taken to lower the flood risk in Malmö, and other cities with similar characteristics, are discussed.

Flood risk awareness during the 2011 floods in the central United States: showcasing the importance of hydrologic data and interagency collaboration

USGS Publications Warehouse

Holmes, Robert R.; Schwein, Noreen O.; Shadie, Charles E.

2012-01-01

Floods have long had a major impact on society and the environment, evidenced by the more than 1,500 federal disaster declarations since 1952 that were associated with flooding. Calendar year 2011 was an epic year for floods in the United States, from the flooding on the Red River of the North in late spring to the Ohio, Mississippi, and Missouri River basin floods in the spring and summer to the flooding caused by Hurricane Irene along the eastern seaboard in August. As a society, we continually seek to reduce flood impacts, with these efforts loosely grouped into two categories: mitigation and risk awareness. Mitigation involves such activities as flood assessment, flood control implementation, and regulatory activities such as storm water and floodplain ordinances. Risk awareness ranges from issuance of flood forecasts and warnings to education of lay audiences about the uncertainties inherent in assessing flood probability and risk. This paper concentrates on the issue of flood risk awareness, specifically the importance of hydrologic data and good interagency communication in providing accurate and timely flood forecasts to maximize risk awareness. The 2011 floods in the central United States provide a case study of the importance of hydrologic data and the value of proper, timely, and organized communication and collaboration around the collection and dissemination of that hydrologic data in enhancing the effectiveness of flood forecasting and flood risk awareness.

Flood frequencies and durations and their response to El Niño Southern Oscillation: Global analysis

NASA Astrophysics Data System (ADS)

Ward, P. J.; Kummu, M.; Lall, U.

2016-08-01

Floods are one of the most serious forms of natural hazards in terms of the damages they cause. In 2012 alone, flood damages exceeded 19 billion. A large proportion of the damages from several recent major flood disasters, such as those in South India and South Carolina (2015), England and Wales (2014), the Mississippi (2012), Thailand (2011), Queensland (Australia) (2010-2011), and Pakistan (2010), were related to the long duration of those flood events. However, most flood risk studies to date do not account for flood duration. In this paper, we provide the first global modelling exercise to assess the link between interannual climate variability and flood duration and frequency. Specifically, we examine relationships between simulated flood events and El Niño Southern Oscillation (ENSO). Our results show that the duration of flooding appears to be more sensitive to ENSO than is the case for flood frequency. At the globally aggregated scale, we found floods to be significantly longer during both El Niño and La Niña years, compared to neutral years. At the scale of individual river basins, we found strong correlations between ENSO and both flood frequency and duration for a large number of basins, with generally stronger correlations for flood duration than for flood frequency. Future research on flood impacts should attempt to incorporate more information on flood durations.

Development of evaluation metod of flood risk in Tokyo metropolitan area

NASA Astrophysics Data System (ADS)

Hirano, J.; Dairaku, K.

2012-12-01

Flood is one of the most significant natural hazards in Japan. In particular, the Tokyo metropolitan area has been affected by several large flood disasters. Investigating potential flood risk in Tokyo metropolitan area is important for development of climate change adaptation strategy. 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. Based on these flood data, we constructed a flood database system for Tokyo metropolitan area for the period from 1961 to 2008 by using ArcGIS software.Based on these flood data , we created flood risk curve, representing the relation ship between damage and exceedbability of flood for the period 1976-2008. Based on the flood risk cruve, we aim to evaluate potential flood risk in the Tokyo metropolitan area and clarify the cause of regional difference in flood risk at Tokyo metropolitan area by considering effect of socio-economic change and climate change

Estimation of flood environmental effects using flood zone mapping techniques in Halilrood Kerman, Iran.

PubMed

Boudaghpour, Siamak; Bagheri, Majid; Bagheri, Zahra

2014-01-01

High flood occurrences with large environmental damages have a growing trend in Iran. Dynamic movements of water during a flood cause different environmental damages in geographical areas with different characteristics such as topographic conditions. In general, environmental effects and damages caused by a flood in an area can be investigated from different points of view. The current essay is aiming at detecting environmental effects of flood occurrences in Halilrood catchment area of Kerman province in Iran using flood zone mapping techniques. The intended flood zone map was introduced in four steps. Steps 1 to 3 pave the way to calculate and estimate flood zone map in the understudy area while step 4 determines the estimation of environmental effects of flood occurrence. Based on our studies, wide range of accuracy for estimating the environmental effects of flood occurrence was introduced by using of flood zone mapping techniques. Moreover, it was identified that the existence of Jiroft dam in the study area can decrease flood zone from 260 hectares to 225 hectares and also it can decrease 20% of flood peak intensity. As a result, 14% of flood zone in the study area can be saved environmentally.

Characterization of remarkable floods in France, a transdisciplinary approach applied on generalized floods of January 1910

NASA Astrophysics Data System (ADS)

Boudou, Martin; Lang, Michel; Vinet, Freddy; Coeur, Denis

2014-05-01

The 2007 Flood Directive promotes the integration and valorization of historical and significant floods in flood risk management (Flood Directive Text, chapter II, and article 4). Taking into account extreme past floods analysis seems necessary in the mitigation process of vulnerability face to flooding risk. In France, this aspect of the Directive was carried out through the elaboration of Preliminary Flood Risk Assessment (PFRA) and the establishment of a 2000 floods list. From this first list, a sample of 176 floods, considered as remarkable has been selected. These floods were compiled in discussion with local authorities in charge of flood management (Lang et al., 2012) and have to be integrated in priority in local risk management policies. However, a consideration emerges about this classification: how a remarkable flood can be defined? According which criteria can it be considered as remarkable? To answer these questions, a methodology has been established by building an evaluation grid of remarkable floods in France. The primary objective of this grid is to analyze the remarkable flood's characteristics (hydrological and meteorological characteristics, sociological- political and economic impacts), and secondly to propose a classification of significant floods selected in the 2011 PFRA. To elaborate this evaluation grid, several issues had to be taken into account. First, the objective is to allow the comparison of events from various periods. These temporal disparities include the integration of various kinds of data and point out the importance of historical hydrology. It is possible to evaluate accurately the characteristics of recent floods by interpreting quantitative data (for example hydrological records. However, for floods that occurred before the 1960's it is necessary resorting to qualitative information such as written sources is necessary (Coeur, Lang, 2008). In a second part the evaluation grid requires equitable criteria in order not to emphasize one flood typology or one flood dynamic (for example flash floods are often over-represented than slow dynamic floods in existing databases). Thus, the selected criteria have to introduce a general overview of flooding risk in France by integrating all typologies: storm surges, torrential floods, rising groundwater level and resulting to flood, etc. The methodology developed for the evaluation grid is inspired by several scientific works related to historical hydrology (Bradzil, 2006; Benito et al., 2004) or extreme floods classification (Kundzewics et al. 2013; Garnier E., 2005). The referenced information are mainly issued from investigations realized for the PFRA (archives, local data),from internet databases on flooding disasters, and from a complementary bibliography (some scientists such as Maurice Pardé a geographer who largely documented French floods during the 20th century). The proposed classification relies on three main axes. Each axis is associated to a set of criteria, each one related to a score (from 0.5 to 4 points), and pointing out a final remarkability score. • The flood intensity characterizing the flood's hazard level. It is composed of the submersion duration, important to valorize floods with slow dynamics as flooding from groundwater, the event peak discharge's return period, and the presence of factors increasing significantly the hazard level (dykes breaks, log jam, sediment transport…) • The flood severity focuses on economic damages, social and political repercussions, media coverage of the event, fatalities number or eventual flood warning failures. Analyzing the flood consequences is essential in order to evaluate the vulnerability of society at disaster date. • The spatial extension of the flood, which contributes complementary information to the two first axes. The evaluation grid was tested and applied on the sample of 176 remarkable events. Around twenty events (from 1856 to 2010) come out with a high remarkability rate. The January 1910's flood is one of these remarkable floods. This event is foremost known for its aftermaths on the Seine basin, where the flood remains the strongest recorded in Paris since 1658. However, its impacts were also widespread to France's Eastern regions (Martin, 2001). To demonstrate the evaluation grid's interest, we propose a deep analysis of the 1910's river flood with the integration of historical documentation. The approach focus on eastern France where the flood remains the highest recorded for several rivers but were often neglected by scientists in favor of Paris's flood. Through a transdisciplinary research based on the evaluation grid method, we will describe the January 1910 flood event and define why it can be considered as a remarkable flood for these regions.

Experimental floods cause ecosystem regime shift in a regulated river.

PubMed

Robinson, Christopher T; Uehlinger, Urs

2008-03-01

Reservoirs have altered the flow regime of most rivers on the globe. To simulate the natural flow regime, experimental floods are being implemented on regulated rivers throughout the world to improve their ecological integrity. As a large-scale disturbance, the long-term sequential use of floods provides an excellent empirical approach to examine ecosystem regime shifts in rivers. This study evaluated the long-term effects of floods (15 floods over eight years) on a regulated river. We hypothesized that sequential floods over time would cause a regime shift in the ecosystem. The floods resulted in little change in the physicochemistry of the river, although particulate organic carbon and particulate phosphorus were lower after the floods. The floods eliminated moss cover on bed sediments within the first year of flooding and maintained low periphyton biomass and benthic organic matter after the third year of flooding. Organic matter in transport was reduced after the third year of flooding, although peaks were still observed during rain events due to tributary inputs and side slopes. The floods reduced macroinvertebrate richness and biomass after the first year of floods, but density was not reduced until the third year. The individual mass of invertebrates decreased by about one-half after the floods. Specific taxa displayed either a loss in abundance, or an increase in abundance, or an increase followed by a loss after the third year. The first three flood years were periods of nonequilibrium with coefficients of variation in all measured parameters increasing two to five times from those before the floods. Coefficients of variation decreased after the third year, although they were still higher than before the floods. Analysis of concordance using Kendall's W confirmed the temporal changes observed in macroinvertebrate assemblage structure. An assessment of individual flood effects showed that later floods had approximately 30% less effect on macroinvertebrates than early floods of similar magnitude, suggesting that the new assemblage structure is more resilient to flood disturbance. We conclude that the floods caused an ecosystem regime shift that took three years to unfold. Additional long-term changes or shifts are expected as new taxa colonize the river from other sources.

Characterising Record Flooding in the United Kingdom

NASA Astrophysics Data System (ADS)

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 worrying reality for those who live in flood-prone areas, and to those who study the upper tail of flood events.

Floods and Flash Flooding

MedlinePlus

Floods and flash flooding Now is the time to determine your area’s flood risk. If you are not sure whether you live in ... If you are in a floodplain, consider buying flood insurance. Do not drive around barricades. If your ...

Flood loss assessment in Can Tho City, Vietnam

NASA Astrophysics Data System (ADS)

Do, T. C.; Kreibich, H.

2012-04-01

Floods are recurring events in the Lower Mekong Basin resulting in loss of life and property, causing damage to agriculture and rural infrastructure, and disrupting social and economic activities. Flood management and mitigation has become a priority issue at the national and regional levels. Besides, it is expected that large areas of the Mekong delta, the Red River delta and the central coast will be flooded by sea-level rise due to climate change. Can Tho City is ranked under the five most flood-tide-influenced cities of Vietnam. It is the biggest city in the Mekong delta and it is located near the Hau river. Like other region of the Mekong delta, Can Tho suffers due to floods from upstream and flood tides from the sea. In the flood season large rural areas of the city are flooded, particularly during tidal days. Flood risk management policy includes preparative measures for living with floods and to minimise the damage caused by floods as well as to take advantage of floods for sustainable development. An intensive literature review, including administrative reports as well as expert interviews have been undertaken to gain more insight into flood characteristics, their consequences and risk mitigation. Therefore, flood damaging processes and trends have been reviewed for Can Tho City and the Mekong Basin in Vietnam. Additionally, suitable flood damage estimation methodologies have been collected as important input for flood risk analyses. On this basis it has been investigated which flood risk mitigation and management strategies promise to be effective in Can Tho City, Vietnam.

44 CFR 60.3 - Flood plain management criteria for flood-prone areas.

Code of Federal Regulations, 2012 CFR

2012-10-01

... minimize or eliminate infiltration of flood waters into the systems; and (6) Require within flood-prone... infiltration of flood waters into the systems and discharges from the systems into flood waters and (ii) onsite...

44 CFR 60.3 - Flood plain management criteria for flood-prone areas.

Code of Federal Regulations, 2014 CFR

2014-10-01

... minimize or eliminate infiltration of flood waters into the systems; and (6) Require within flood-prone... infiltration of flood waters into the systems and discharges from the systems into flood waters and (ii) onsite...

44 CFR 60.3 - Flood plain management criteria for flood-prone areas.

Code of Federal Regulations, 2013 CFR

2013-10-01

... minimize or eliminate infiltration of flood waters into the systems; and (6) Require within flood-prone... infiltration of flood waters into the systems and discharges from the systems into flood waters and (ii) onsite...

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

NASA Astrophysics Data System (ADS)

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. When substantial flooding occurs, the USGS mobilizes personnel to collect streamflow data in affected areas. Streamflow data improve flood forecasting and provide data for flood-frequency analysis for floodplain management, design of structures located in floodplains, and related water studies. An important lesson learned is that nature provides environmental signs before and during floods that can help people avoid hazard areas. Important contributions to flood science as a result of the 1976 flood include development of paleoflood methods to interpret the preserved flood-plain stratigraphy to document the number, magnitude, and age of floods that occurred prior to streamflow monitoring. These methods and data on large floods can be used in many mountain-river systems to help us better understand flood hazards and plan for the future. For example, according to conventional flood-frequency analysis, the 1976 Big Thompson flood had a flood recurrence interval of about 100 years. However, paleoflood research indicated the 1976 flood was the largest in about the last 10,000 years in the basin and had a flood recurrence interval in excess of 1,000 years.

Summary of U.S. Geological Survey reports documenting flood profiles of streams in Iowa, 1963-2012

USGS Publications Warehouse

Eash, David A.

2014-01-01

This report is part of an ongoing program that is publishing flood profiles of streams in Iowa. The program is managed by the U.S. Geological Survey in cooperation with the Iowa Department of Transportation and the Iowa Highway Research Board (Project HR-140). Information from flood profiles is used by engineers to analyze and design bridges, culverts, and roadways. This report summarizes 47 U.S. Geological Survey flood-profile reports that were published for streams in Iowa during a 50-year period from 1963 to 2012. Flood events profiled in the reports range from 1903 to 2010. Streams in Iowa that have been selected for the preparation of flood-profile reports typically have drainage areas of 100 square miles or greater, and the documented flood events have annual exceedance probabilities of less than 2 to 4 percent. This report summarizes flood-profile measurements, changes in flood-profile report content throughout the years, streams that were profiled in the reports, the occurrence of flood events profiled, and annual exceedance-probability estimates of observed flood events. To develop flood profiles for selected flood events for selected stream reaches, the U.S. Geological Survey measured high-water marks and river miles at selected locations. A total of 94 stream reaches have been profiled in U.S. Geological Survey flood-profile reports. Three rivers in Iowa have been profiled along the same stream reach for five different flood events and six rivers in Iowa have been profiled along the same stream reach for four different flood events. Floods were profiled for June flood events for 18 different years, followed by July flood events for 13 years, May flood events for 11 years, and April flood events for 9 years. Most of the flood-profile reports include estimates of annual exceedance probabilities of observed flood events at streamgages located along profiled stream reaches. Comparisons of 179 historic and updated annual exceedance-probability estimates indicate few differences that are considered substantial between the historic and updated estimates for the observed flood events. Overall, precise comparisons for 114 observed flood events indicate that updated annual exceedance probabilities have increased for most of the observed flood events compared to the historic annual exceedance probabilities. Multiple large flood events exceeding the 2-percent annual exceedance-probability discharge estimate occurred at 37 of 98 selected streamgages during 1960–2012. Five large flood events were recorded at two streamgages in Ames during 1990–2010 and four large flood events were recorded at four other streamgages during 1973–2010. Results of Kendall’s tau trend-analysis tests for 35 of 37 selected streamgages indicate that a statistically significant trend is not evident for the 1963–2012 period of record; nor is an overall clear positive or negative trend evident for the 37 streamgages.

Metabolic profiles of flooding-tolerant mechanism in early-stage soybean responding to initial stress.

PubMed

Wang, Xin; Zhu, Wei; Hashiguchi, Akiko; Nishimura, Minoru; Tian, Jingkui; Komatsu, Setsuko

2017-08-01

Metabolomic analysis of flooding-tolerant mutant and abscisic acid-treated soybeans suggests that accumulated fructose might play a role in initial flooding tolerance through regulation of hexokinase and phosphofructokinase. Soybean is sensitive to flooding stress, which markedly reduces plant growth. To explore the mechanism underlying initial-flooding tolerance in soybean, mass spectrometry-based metabolomic analysis was performed using flooding-tolerant mutant and abscisic-acid treated soybeans. Among the commonly-identified metabolites in both flooding-tolerant materials, metabolites involved in carbohydrate and organic acid displayed same profile at initial-flooding stress. Sugar metabolism was highlighted in both flooding-tolerant materials with the decreased and increased accumulation of sucrose and fructose, respectively, compared to flooded soybeans. Gene expression of hexokinase 1 was upregulated in flooded soybean; however, it was downregulated in both flooding-tolerant materials. Metabolites involved in carbohydrate/organic acid and proteins related to glycolysis/tricarboxylic acid cycle were integrated. Increased protein abundance of phosphofructokinase was identified in both flooding-tolerant materials, which was in agreement with its enzyme activity. Furthermore, sugar metabolism was pointed out as the tolerant-responsive process at initial-flooding stress with the integration of metabolomics, proteomics, and transcriptomics. Moreover, application of fructose declined the increased fresh weight of plant induced by flooding stress. These results suggest that fructose might be the critical metabolite through regulation of hexokinase and phosphofructokinase to confer initial-flooding stress in soybean.

Flood maps in Europe - methods, availability and use

NASA Astrophysics Data System (ADS)

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 their flood hazards. A flood risk based map that includes consequences, however, has yet to be developed by most countries.

78 FR 45938 - Final Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-30

...] Final Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final notice. SUMMARY: Flood hazard determinations, which may include additions or modifications of Base Flood Elevations (BFEs), base flood depths, Special Flood Hazard Area (SFHA) boundaries or zone designations, or...

Estimation of the Relative Severity of Floods in Small Ungauged Catchments for Preliminary Observations on Flash Flood Preparedness: A Case Study in Korea

PubMed Central

Kim, Eung Seok; Choi, Hyun Il

2012-01-01

An increase in the occurrence of sudden local flooding of great volume and short duration has caused significant danger and loss of life and property in Korea as well as many other parts of the World. Since such floods usually accompanied by rapid runoff and debris flow rise quite quickly with little or no advance warning to prevent flood damage, this study presents a new flash flood indexing methodology to promptly provide preliminary observations regarding emergency preparedness and response to flash flood disasters in small ungauged catchments. Flood runoff hydrographs are generated from a rainfall-runoff model for the annual maximum rainfall series of long-term observed data in the two selected small ungauged catchments. The relative flood severity factors quantifying characteristics of flood runoff hydrographs are standardized by the highest recorded maximum value, and then averaged to obtain the flash flood index only for flash flood events in each study catchment. It is expected that the regression equations between the proposed flash flood index and rainfall characteristics can provide the basis database of the preliminary information for forecasting the local flood severity in order to facilitate flash flood preparedness in small ungauged catchments. PMID:22690208

Prediction of extreme flood in August 2002 along the Upper-Danube in Hungary

NASA Astrophysics Data System (ADS)

Sütheö, L.; Bálint, G.; Szlávik, L.

2003-04-01

Specific for summer conditions weather situation caused the flood. A cyclone reached the region of Alps, humid air and great instability of stratification produced high precipitation throughout the region in two vawes. The flood has reached historical maxima on the reach between Bratislava Budapest. This is the first flood of this magnitude, which has passed this section of the Danube without breaching the dikes, flood embankments. The peak flow rate attenuated along this section from 10 000 m3s-1 to 8600 m3s-1. Specifics of flood routing conditions are discussed. Barrages and training has changed flood routing patterns along the Austrian and joined Slovak Hungarian sections of the Danube. Increased velocity of wave propagation decreases the impact of superposition of consequent flood waves, but attenuation of flood waves is also less expressed. The most significant impact on the present flood was, that this was the first flood of this magnitude, which has passed this section of the Danube without breaching the flood embankments. Earlier extreme floods including the 1954 and 1965 floods resulted failure of the dikes and spill over of 1.5- 2 million m3 of water to the protected floodplain. This time the flood was contained within the floodberm.

An Approach to Flooding Inundation Combining the Streamflow Prediction Tool (SPT) and Downscaled Soil Moisture

NASA Astrophysics Data System (ADS)

Cotterman, K. A.; Follum, M. L.; Pradhan, N. R.; Niemann, J. D.

2017-12-01

Flooding impacts numerous aspects of society, from localized flash floods to continental-scale flood events. Many numerical flood models focus solely on riverine flooding, with some capable of capturing both localized and continental-scale flood events. However, these models neglect flooding away from channels that are related to excessive ponding, typically found in areas with flat terrain and poorly draining soils. In order to obtain a holistic view of flooding, we combine flood results from the Streamflow Prediction Tool (SPT), a riverine flood model, with soil moisture downscaling techniques to determine if a better representation of flooding is obtained. This allows for a more holistic understanding of potential flood prone areas, increasing the opportunity for more accurate warnings and evacuations during flooding conditions. Thirty-five years of near-global historical streamflow is reconstructed with continental-scale flow routing of runoff from global land surface models. Elevation data was also obtained worldwide, to establish a relationship between topographic attributes and soil moisture patterns. Derived soil moisture data is validated against observed soil moisture, increasing confidence in the ability to accurately capture soil moisture patterns. Potential flooding situations can be examined worldwide, with this study focusing on the United States, Central America, and the Philippines.

Expression of root-related transcription factors associated with flooding tolerance of soybean (Glycine max).

PubMed

Valliyodan, Babu; Van Toai, Tara T; Alves, Jose Donizeti; de Fátima P Goulart, Patricia; Lee, Jeong Dong; Fritschi, Felix B; Rahman, Mohammed Atiqur; Islam, Rafiq; Shannon, J Grover; Nguyen, Henry T

2014-09-29

Much research has been conducted on the changes in gene expression of the model plant Arabidopsis to low-oxygen stress. Flooding results in a low oxygen environment in the root zone. However, there is ample evidence that tolerance to soil flooding is more than tolerance to low oxygen alone. In this study, we investigated the physiological response and differential expression of root-related transcription factors (TFs) associated with the tolerance of soybean plants to soil flooding. Differential responses of PI408105A and S99-2281 plants to ten days of soil flooding were evaluated at physiological, morphological and anatomical levels. Gene expression underlying the tolerance response was investigated using qRT-PCR of root-related TFs, known anaerobic genes, and housekeeping genes. Biomass of flood-sensitive S99-2281 roots remained unchanged during the entire 10 days of flooding. Flood-tolerant PI408105A plants exhibited recovery of root growth after 3 days of flooding. Flooding induced the development of aerenchyma and adventitious roots more rapidly in the flood-tolerant than the flood-sensitive genotype. Roots of tolerant plants also contained more ATP than roots of sensitive plants at the 7th and 10th days of flooding. Quantitative transcript analysis identified 132 genes differentially expressed between the two genotypes at one or more time points of flooding. Expression of genes related to the ethylene biosynthesis pathway and formation of adventitious roots was induced earlier and to higher levels in roots of the flood-tolerant genotype. Three potential flood-tolerance TFs which were differentially expressed between the two genotypes during the entire 10-day flooding duration were identified. This study confirmed the expression of anaerobic genes in response to soil flooding. Additionally, the differential expression of TFs associated with soil flooding tolerance was not qualitative but quantitative and temporal. Functional analyses of these genes will be necessary to reveal their potential to enhance flooding tolerance of soybean cultivars.

Expression of Root-Related Transcription Factors Associated with Flooding Tolerance of Soybean (Glycine max)

PubMed Central

Valliyodan, Babu; Van Toai, Tara T.; Alves, Jose Donizeti; de Fátima P. Goulart, Patricia; Lee, Jeong Dong; Fritschi, Felix B.; Rahman, Mohammed Atiqur; Islam, Rafiq; Shannon, J. Grover; Nguyen, Henry T.

2014-01-01

Much research has been conducted on the changes in gene expression of the model plant Arabidopsis to low-oxygen stress. Flooding results in a low oxygen environment in the root zone. However, there is ample evidence that tolerance to soil flooding is more than tolerance to low oxygen alone. In this study, we investigated the physiological response and differential expression of root-related transcription factors (TFs) associated with the tolerance of soybean plants to soil flooding. Differential responses of PI408105A and S99-2281 plants to ten days of soil flooding were evaluated at physiological, morphological and anatomical levels. Gene expression underlying the tolerance response was investigated using qRT-PCR of root-related TFs, known anaerobic genes, and housekeeping genes. Biomass of flood-sensitive S99-2281 roots remained unchanged during the entire 10 days of flooding. Flood-tolerant PI408105A plants exhibited recovery of root growth after 3 days of flooding. Flooding induced the development of aerenchyma and adventitious roots more rapidly in the flood-tolerant than the flood-sensitive genotype. Roots of tolerant plants also contained more ATP than roots of sensitive plants at the 7th and 10th days of flooding. Quantitative transcript analysis identified 132 genes differentially expressed between the two genotypes at one or more time points of flooding. Expression of genes related to the ethylene biosynthesis pathway and formation of adventitious roots was induced earlier and to higher levels in roots of the flood-tolerant genotype. Three potential flood-tolerance TFs which were differentially expressed between the two genotypes during the entire 10-day flooding duration were identified. This study confirmed the expression of anaerobic genes in response to soil flooding. Additionally, the differential expression of TFs associated with soil flooding tolerance was not qualitative but quantitative and temporal. Functional analyses of these genes will be necessary to reveal their potential to enhance flooding tolerance of soybean cultivars. PMID:25268626

An empirical assessment of which inland floods can be managed

USGS Publications Warehouse

Mogollón, Beatriz; Frimpong, Emmanuel A.; Hoegh, Andrew B.; Angermeier, Paul

2016-01-01

Riverine flooding is a significant global issue. Although it is well documented that the influence of landscape structure on floods decreases as flood size increases, studies that define a threshold flood-return period, above which landscape features such as topography, land cover and impoundments can curtail floods, are lacking. Further, the relative influences of natural versus built features on floods is poorly understood. Assumptions about the types of floods that can be managed have considerable implications for the cost-effectiveness of decisions to invest in transforming land cover (e.g., reforestation) and in constructing structures (e.g., storm-water ponds) to control floods. This study defines parameters of floods for which changes in landscape structure can have an impact. We compare nine flood-return periods across 31 watersheds with widely varying topography and land cover in the southeastern United States, using long-term hydrologic records (≥20 years). We also assess the effects of built flow-regulating features (best management practices and artificial water bodies) on selected flood metrics across urban watersheds. We show that landscape features affect magnitude and duration of only those floods with return periods ≤10 years, which suggests that larger floods cannot be managed effectively by manipulating landscape structure. Overall, urban watersheds exhibited larger (270 m3/s) but quicker (0.41 days) floods than non-urban watersheds (50 m3/s and 1.5 days). However, urban watersheds with more flow-regulating features had lower flood magnitudes (154 m3/s), but similar flood durations (0.55 days), compared to urban watersheds with fewer flow-regulating features (360 m3/s and 0.23 days). Our analysis provides insight into the magnitude, duration and count of floods that can be curtailed by landscape structure and its management. Our findings are relevant to other areas with similar climate, topography, and land use, and can help ensure that investments in flood management are made wisely after considering the limitations of landscape features to regulate floods.

Impact of Reservoir Operation to the Inflow Flood - a Case Study of Xinfengjiang Reservoir

NASA Astrophysics Data System (ADS)

Chen, L.

2017-12-01

Building of reservoir shall impact the runoff production and routing characteristics, and changes the flood formation. This impact, called as reservoir flood effect, could be divided into three parts, including routing effect, volume effect and peak flow effect, and must be evaluated in a whole by using hydrological model. After analyzing the reservoir flood formation, the Liuxihe Model for reservoir flood forecasting is proposed. The Xinfengjiang Reservoir is studied as a case. Results show that the routing effect makes peak flow appear 4 to 6 hours in advance, volume effect is bigger for large flood than small one, and when rainfall focus on the reservoir area, this effect also increases peak flow largely, peak flow effect makes peak flow increase 6.63% to 8.95%. Reservoir flood effect is obvious, which have significant impact to reservoir flood. If this effect is not considered in the flood forecasting model, the flood could not be forecasted accurately, particularly the peak flow. Liuxihe Model proposed for Xinfengjiang Reservoir flood forecasting has a good performance, and could be used for real-time flood forecasting of Xinfengjiang Reservoir.Key words: Reservoir flood effect, reservoir flood forecasting, physically based distributed hydrological model, Liuxihe Model, parameter optimization

The link between land use and flood risk assessment in urban areas

NASA Astrophysics Data System (ADS)

Sörensen, Johanna; Kalantari, Zahra

2017-04-01

Densification of urban areas rises a concern for increased pluvial flooding. Flood risk in urban areas might rise under impact of land use changes. Urbanisation involves conversion of natural areas to impermeable areas giving lower infiltration rates and increased runoff. When high-intense rainfall excess the capacity of the drainage system in a city, high runoff causes pluvial flooding in low-laying areas. In the present study, a long time series (20 years) of geo-referenced flood claims from property owners has been collected and analysed in detail to assess flood risk under impact of land use changes in urban areas. The flood claim data come from property owners with flood insurance that covers property loss from overland flooding, groundwater intrusion through basement walls, as well as flooding from the drainage system, and are used as a proxy for flood severity. The spatial relationships between land use change and flood occurrences in different urban areas were analysed. Special emphasis were put on how nature-based solutions and blue-green infrastructure relates to flood risk. The relationships defined by a statistical method explaining the tendencies where the land use change contributes to flood risk changes and others engaged factors.

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

NASA Astrophysics Data System (ADS)

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.

Geomorphic changes caused by the 2011 flood at selected sites along the lower Missouri River and comparison to historical floods: Chapter H in 2011 floods of the central United States

USGS Publications Warehouse

Juracek, Kyle E.

2014-01-01

An analysis of recent and historical U.S. Geological Survey streamgage information was used to assess geomorphic changes caused by the 2011 flood, in comparison to selected historical floods, at three streamgage sites along the lower Missouri River—Sioux City, Iowa; Omaha, Nebraska; and Kansas City, Missouri. Channel-width change was not evident at the three streamgage sites following the 2011 flood and likely was inhibited by bank stabilization. Pronounced changes in channel-bed elevation were indicated. At Sioux City and Omaha, the geomorphic effects of the 2011 flood were similar in terms of the magnitude of channelbed scour and recovery. At both sites, the 2011 flood caused pronounced scour (about 3 feet) of the channel bed; however, at Omaha, most of the channel-bed scour occurred after the flood had receded. More than 1 year after the flood, the channel bed had only partially recovered (about 1 foot) at both sites. Pronounced scour (about 3 feet at Sioux City and about 1.5 feet at Omaha) also was caused by the 1952 flood, which had a substantially larger peak discharge but was much shorter in duration at both sites. Again, at Omaha, most of the channel- bed scour occurred after the flood had receded. At Sioux City, substantial recovery of the channel bed (about 2.5 feet) was documented 1 year after the 1952 flood. Recovery to the pre-flood elevation was complete by April 1954. The greater recovery following the 1952 flood, compared to the 2011 flood, likely was related to a more abundant sediment supply because the flood predated the completion of most of the main-stem dam, channelization, and bank stabilization projects. At Omaha, following the 1952 flood, the channel bed never fully recovered to its pre-flood elevation. The geomorphic effect of the 2011 flood at Kansas City was fill (about 1 foot) on the channel bed followed by relative stability. The 1952 flood, which had a substantially larger peak discharge but was much shorter in duration, caused modest fill (about 0.5 foot) on the channel bed. The 1993 flood, which also had a substantially larger peak discharge but was much shorter in duration, caused pronounced scour of the channel bed (possibly as much as 4 feet). Similar to the floods at Omaha, much of the channel-bed scour at Kansas City occurred after the 1993 flood had receded. More than 1 year after the 1993 flood, following partial recovery (about 1 foot), the channel bed had stabilized, at least temporarily. Following the 1993 flood, the channel bed never fully recovered to its pre-flood elevation. For each flood in the post-dam era that resulted in substantial channel-bed scour (Sioux City in 2011, Omaha in 2011, Kansas City in 1993), recovery of the channel bed to its pre-flood elevation had not occurred more than 1 year after the flood (20 years after the 1993 flood at Kansas City). Thus, the possibility exists that channel-bed scour caused by large floods may have a cumulative effect along the lower Missouri River. The persistence of the flood-related decreases in channel-bed elevation may be indicative of the constrained ability of the channel to recover given a limited sediment supply caused by one or more of the following factors: upstream storage of sediment in reservoirs, bank stabilization, commercial sand dredging, depletion of readily available sediment by the flood, and a lack of post-flood sediment contributions from tributaries.

The relationship between precipitation and insurance data for floods in a Mediterranean region (northeast Spain)

NASA Astrophysics Data System (ADS)

Cortès, Maria; Turco, Marco; Llasat-Botija, Montserrat; Llasat, Maria Carmen

2018-03-01

Floods in the Mediterranean region are often surface water floods, in which intense precipitation is usually the main driver. Determining the link between the causes and impacts of floods can make it easier to calculate the level of flood risk. However, up until now, the limitations in quantitative observations for flood-related damages have been a major obstacle when attempting to analyse flood risk in the Mediterranean. Flood-related insurance damage claims for the last 20 years could provide a proxy for flood impact, and this information is now available in the Mediterranean region of Catalonia, in northeast Spain. This means a comprehensive analysis of the links between flood drivers and impacts is now possible. The objective of this paper is to develop and evaluate a methodology to estimate flood damages from heavy precipitation in a Mediterranean region. Results show that our model is able to simulate the probability of a damaging event as a function of precipitation. The relationship between precipitation and damage provides insights into flood risk in the Mediterranean and is also promising for supporting flood management strategies.

Interconnected ponds operation for flood hazard distribution

NASA Astrophysics Data System (ADS)

Putra, S. S.; Ridwan, B. W.

2016-05-01

The climatic anomaly, which comes with extreme rainfall, will increase the flood hazard in an area within a short period of time. The river capacity in discharging the flood is not continuous along the river stretch and sensitive to the flood peak. This paper contains the alternatives on how to locate the flood retention pond that are physically feasible to reduce the flood peak. The flood ponds were designed based on flood curve number criteria (TR-55, USDA) with the aim of rapid flood peak capturing and gradual flood retuning back to the river. As a case study, the hydrologic condition of upper Ciliwung river basin with several presumed flood pond locations was conceptually designed. A fundamental tank model that reproducing the operation of interconnected ponds was elaborated to achieve the designed flood discharge that will flows to the downstream area. The flood hazard distribution status, as the model performance criteria, will be computed within Ciliwung river reach in Manggarai Sluice Gate spot. The predicted hazard reduction with the operation of the interconnected retention area result had been bench marked with the normal flow condition.

Long-term effects of flooding on mortality in England and Wales, 1994-2005: controlled interrupted time-series analysis

PubMed Central

2011-01-01

Background Limited evidence suggests that being flooded may increase mortality and morbidity among affected householders not just at the time of the flood but for months afterwards. The objective of this study is to explore the methods for quantifying such long-term health effects of flooding by analysis of routine mortality registrations in England and Wales. Methods Mortality data, geo-referenced by postcode of residence, were linked to a national database of flood events for 1994 to 2005. The ratio of mortality in the post-flood year to that in the pre-flood year within flooded postcodes was compared with that in non-flooded boundary areas (within 5 km of a flood). Further analyses compared the observed number of flood-area deaths in the year after flooding with the number expected from analysis of mortality trends stratified by region, age-group, sex, deprivation group and urban-rural status. Results Among the 319 recorded floods, there were 771 deaths in the year before flooding and 693 deaths in the year after (post-/pre-flood ratio of 0.90, 95% CI 0.82, 1.00). This ratio did not vary substantially by age, sex, population density or deprivation. A similar post-flood 'deficit' of deaths was suggested by the analyses based on observed/expected deaths. Conclusions The observed post-flood 'deficit' of deaths is counter-intuitive and difficult to interpret because of the possible influence of population displacement caused by flooding. The bias that might arise from such displacement remains unquantified but has important implications for future studies that use place of residence as a marker of exposure. PMID:21288358

Extent and frequency of floods on the Schuylkill River near Phoenixville and Pottstown, Pennsylvania

USGS Publications Warehouse

Busch, William F.; Shaw, Lewis C.

1973-01-01

Knowledge of the frequency and extent of flooding is an important requirement for the design of all works of man bordering or encroaching on flood plains. The proper design of bridges, culverts, dams, highways, levees, reservoirs, sewage-disposal systems, waterworks and all structures on the flood plains of streams requires careful consideration of flood hazards. -1- By use of relations presented in this report, the extent, depth, and frequency of flooding can be estimated for any site along the reach of the Schuylkill River from Oaks to Pottstown. These flood data are presented so that regulatory agencies, organizations, and individuals may have a technical basis for making decisions on the use of flood-prone areas. The Delaware River Basin Commission and the U. S. Geological Survey regard this program of flood-plain-inundation studies as a positive step toward flood-damage prevention. Flood-plaininundation studies are a prerequisite to flood-plain management which may include a mixture of flood-control structures and/or land-use regulations. Both physical works and flood-plain regulations are included in the Comprehensive Plan for development of the Delaware River basin, of which the Schuylkill River is a part. Recommendations for land use, or suggestions for limitations of land use, are not made herein. Other reports on use and regulation of land in flood-prone areas are available (Dola, 1961; White, 1961; American Society of Civil Engineers Task Force on Flood Plain Regulations, 1962; and Goddard, 1963). The primary responsibility for planning for optimum land use in the flood plain and the implementation of flood-plain zoning or other regulations to achieve such optimum use rests with State, and local interests.

Self-Reported and FEMA Flood Exposure Assessment after Hurricane Sandy: Association with Mental Health Outcomes.

PubMed

Lieberman-Cribbin, Wil; Liu, Bian; Schneider, Samantha; Schwartz, Rebecca; Taioli, Emanuela

2017-01-01

Hurricane Sandy caused extensive physical and economic damage; the long-term mental health consequences are unknown. Flooding is a central component of hurricane exposure, influencing mental health through multiple pathways that unfold over months after flooding recedes. Here we assess the concordance in self-reported and Federal Emergency Management (FEMA) flood exposure after Hurricane Sandy and determine the associations between flooding and anxiety, depression, and post-traumatic stress disorder (PTSD). Self-reported flood data and mental health symptoms were obtained through validated questionnaires from New York City and Long Island residents (N = 1231) following Sandy. Self-reported flood data was compared to FEMA data obtained from the FEMA Modeling Task Force Hurricane Sandy Impact Analysis. Multivariable logistic regressions were performed to determine the relationship between flooding exposure and mental health outcomes. There were significant discrepancies between self-reported and FEMA flood exposure data. Self-reported dichotomous flooding was positively associated with anxiety (ORadj: 1.5 [95% CI: 1.1-1.9]), depression (ORadj: 1.7 [1.3-2.2]), and PTSD (ORadj: 2.5 [1.8-3.4]), while self-reported continuous flooding was associated with depression (ORadj: 1.1 [1.01-1.12]) and PTSD (ORadj: 1.2 [1.1-1.2]). Models with FEMA dichotomous flooding (ORadj: 2.1 [1.5-2.8]) or FEMA continuous flooding (ORadj: 1.1 [1.1-1.2]) were only significantly associated with PTSD. Associations between mental health and flooding vary according to type of flood exposure measure utilized. Future hurricane preparedness and recovery efforts must integrate micro and macro-level flood exposures in order to accurately determine flood exposure risk during storms and realize the long-term importance of flooding on these three mental health symptoms.

An Integrated Urban Flood Analysis System in South Korea

NASA Astrophysics Data System (ADS)

Moon, Young-Il; Kim, Min-Seok; Yoon, Tae-Hyung; Choi, Ji-Hyeok

2017-04-01

Due to climate change and the rapid growth of urbanization, the frequency of concentrated heavy rainfall has caused urban floods. As a result, we studied climate change in Korea and developed an integrated flood analysis system that systematized technology to quantify flood risk and flood forecasting in urban areas. This system supports synthetic decision-making through real-time monitoring and prediction on flash rain or short-term rainfall by using radar and satellite information. As part of the measures to deal with the increase of inland flood damage, we have found it necessary to build a systematic city flood prevention system that systematizes technology to quantify flood risk as well as flood forecast, taking into consideration both inland and river water. This combined inland-river flood analysis system conducts prediction on flash rain or short-term rainfall by using radar and satellite information and performs prompt and accurate prediction on the inland flooded area. In addition, flood forecasts should be accurate and immediate. Accurate flood forecasts signify that the prediction of the watch, warning time and water level is precise. Immediate flood forecasts represent the forecasts lead time which is the time needed to evacuate. Therefore, in this study, in order to apply rainfall-runoff method to medium and small urban stream for flood forecasts, short-term rainfall forecasting using radar is applied to improve immediacy. Finally, it supports synthetic decision-making for prevention of flood disaster through real-time monitoring. Keywords: Urban Flood, Integrated flood analysis system, Rainfall forecasting, Korea Acknowledgments This research was supported by a grant (16AWMP-B066744-04) from Advanced Water Management Research Program (AWMP) funded by Ministry of Land, Infrastructure and Transport of Korean government.

Self-Reported and FEMA Flood Exposure Assessment after Hurricane Sandy: Association with Mental Health Outcomes

PubMed Central

Liu, Bian; Schneider, Samantha; Schwartz, Rebecca; Taioli, Emanuela

2017-01-01

Hurricane Sandy caused extensive physical and economic damage; the long-term mental health consequences are unknown. Flooding is a central component of hurricane exposure, influencing mental health through multiple pathways that unfold over months after flooding recedes. Here we assess the concordance in self-reported and Federal Emergency Management (FEMA) flood exposure after Hurricane Sandy and determine the associations between flooding and anxiety, depression, and post-traumatic stress disorder (PTSD). Self-reported flood data and mental health symptoms were obtained through validated questionnaires from New York City and Long Island residents (N = 1231) following Sandy. Self-reported flood data was compared to FEMA data obtained from the FEMA Modeling Task Force Hurricane Sandy Impact Analysis. Multivariable logistic regressions were performed to determine the relationship between flooding exposure and mental health outcomes. There were significant discrepancies between self-reported and FEMA flood exposure data. Self-reported dichotomous flooding was positively associated with anxiety (ORadj: 1.5 [95% CI: 1.1–1.9]), depression (ORadj: 1.7 [1.3–2.2]), and PTSD (ORadj: 2.5 [1.8–3.4]), while self-reported continuous flooding was associated with depression (ORadj: 1.1 [1.01–1.12]) and PTSD (ORadj: 1.2 [1.1–1.2]). Models with FEMA dichotomous flooding (ORadj: 2.1 [1.5–2.8]) or FEMA continuous flooding (ORadj: 1.1 [1.1–1.2]) were only significantly associated with PTSD. Associations between mental health and flooding vary according to type of flood exposure measure utilized. Future hurricane preparedness and recovery efforts must integrate micro and macro-level flood exposures in order to accurately determine flood exposure risk during storms and realize the long-term importance of flooding on these three mental health symptoms. PMID:28129410

Process-based selection of copula types for flood peak-volume relationships in Northwest Austria: a case study

NASA Astrophysics Data System (ADS)

Kohnová, Silvia; Gaál, Ladislav; Bacigál, Tomáš; Szolgay, Ján; Hlavčová, Kamila; Valent, Peter; Parajka, Juraj; Blöschl, Günter

2016-12-01

The case study aims at selecting optimal bivariate copula models of the relationships between flood peaks and flood volumes from a regional perspective with a particular focus on flood generation processes. Besides the traditional approach that deals with the annual maxima of flood events, the current analysis also includes all independent flood events. The target region is located in the northwest of Austria; it consists of 69 small and mid-sized catchments. On the basis of the hourly runoff data from the period 1976- 2007, independent flood events were identified and assigned to one of the following three types of flood categories: synoptic floods, flash floods and snowmelt floods. Flood events in the given catchment are considered independent when they originate from different synoptic situations. Nine commonly-used copula types were fitted to the flood peak - flood volume pairs at each site. In this step, two databases were used: i) a process-based selection of all the independent flood events (three data samples at each catchment) and ii) the annual maxima of the flood peaks and the respective flood volumes regardless of the flood processes (one data sample per catchment). The goodness-of-fit of the nine copula types was examined on a regional basis throughout all the catchments. It was concluded that (1) the copula models for the flood processes are discernible locally; (2) the Clayton copula provides an unacceptable performance for all three processes as well as in the case of the annual maxima; (3) the rejection of the other copula types depends on the flood type and the sample size; (4) there are differences in the copulas with the best fits: for synoptic and flash floods, the best performance is associated with the extreme value copulas; for snowmelt floods, the Frank copula fits the best; while in the case of the annual maxima, no firm conclusion could be made due to the number of copulas with similarly acceptable overall performances. The general conclusion from this case study is that treating flood processes separately is beneficial; however, the usually available sample size in such real life studies is not sufficient to give generally valid recommendations for engineering design tasks.

Developing a Global Database of Historic Flood Events to Support Machine Learning Flood Prediction in Google Earth Engine

NASA Astrophysics Data System (ADS)

Tellman, B.; Sullivan, J.; Kettner, A.; Brakenridge, G. R.; Slayback, D. A.; Kuhn, C.; Doyle, C.

2016-12-01

There is an increasing need to understand flood vulnerability as the societal and economic effects of flooding increases. Risk models from insurance companies and flood models from hydrologists must be calibrated based on flood observations in order to make future predictions that can improve planning and help societies reduce future disasters. Specifically, to improve these models both traditional methods of flood prediction from physically based models as well as data-driven techniques, such as machine learning, require spatial flood observation to validate model outputs and quantify uncertainty. A key dataset that is missing for flood model validation is a global historical geo-database of flood event extents. Currently, the most advanced database of historical flood extent is hosted and maintained at the Dartmouth Flood Observatory (DFO) that has catalogued 4320 floods (1985-2015) but has only mapped 5% of these floods. We are addressing this data gap by mapping the inventory of floods in the DFO database to create a first-of- its-kind, comprehensive, global and historical geospatial database of flood events. To do so, we combine water detection algorithms on MODIS and Landsat 5,7 and 8 imagery in Google Earth Engine to map discrete flood events. The created database will be available in the Earth Engine Catalogue for download by country, region, or time period. This dataset can be leveraged for new data-driven hydrologic modeling using machine learning algorithms in Earth Engine's highly parallelized computing environment, and we will show examples for New York and Senegal.

44 CFR 78.5 - Flood Mitigation Plan development.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true 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...

44 CFR 78.5 - Flood Mitigation Plan development.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 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...

44 CFR 78.5 - Flood Mitigation Plan development.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 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...

The European flood risk directive: challenges for research

NASA Astrophysics Data System (ADS)

Mostert, E.; Junier, S. J.

2009-07-01

In recent years, flood management has shifted from protection against floods to managing the risks of floods. In Europe, this shift is reflected in the Flood risk directive of October 2007 (2007/60/EC; FRD). The FRD requires EU Member States to undertake a preliminary assessment of flood risks and, for areas with a significant flood risk, to prepare flood hazard and flood risk maps and flood risk management plans. The purpose of this paper is to introduce the FRD and discuss the challenges that the FRD poses to research. These challenges include the issue how to define and measure ''flood risk'', the selection of alternatives to be assessed, coping with uncertainty, risk communication, nurturing trust and promoting collaboration. These research challenges cannot be addressed properly within any single discipline and without involving the flood risk managers and other stakeholders. The paper therefore concludes that there is a large need for interdisciplinary and participatory research. This constitutes in fact the biggest research challenge.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Ootegem, Luc; SHERPPA — Ghent University; Verhofstadt, Elsy

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-estimationmore » 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.« less

Communicating Flood Risk with Street-Level Data

NASA Astrophysics Data System (ADS)

Sanders, B. F.; Matthew, R.; Houston, D.; Cheung, W. H.; Karlin, B.; Schubert, J.; Gallien, T.; Luke, A.; Contreras, S.; Goodrich, K.; Feldman, D.; Basolo, V.; Serrano, K.; Reyes, A.

2015-12-01

Coastal communities around the world face significant and growing flood risks that require an accelerating adaptation response, and fine-resolution urban flood models could serve a pivotal role in enabling communities to meet this need. Such models depict impacts at the level of individual buildings and land parcels or "street level" - the same spatial scale at which individuals are best able to process flood risk information - constituting a powerful tool to help communities build better understandings of flood vulnerabilities and identify cost-effective interventions. To measure understanding of flood risk within a community and the potential impact of street-level models, we carried out a household survey of flood risk awareness in Newport Beach, California, a highly urbanized coastal lowland that presently experiences nuisance flooding from high tides, waves and rainfall and is expected to experience a significant increase in flood frequency and intensity with climate change. Interviews were completed with the aid of a wireless-enabled tablet device that respondents could use to identify areas they understood to be at risk of flooding and to view either a Federal Emergency Management Agency (FEMA) flood map or a more detailed map prepared with a hydrodynamic urban coastal flood model (UCI map) built with grid cells as fine as 3 m resolution and validated with historical flood data. Results indicate differences in the effectiveness of the UCI and FEMA maps at communicating the spatial distribution of flood risk, gender differences in how the maps affect flood understanding, and spatial biases in the perception of flood vulnerabilities.

Development of flood profiles and flood-inundation maps for the Village of Killbuck, Ohio

USGS Publications Warehouse

Ostheimer, Chad J.

2013-01-01

Digital flood-inundation maps for a reach of Killbuck Creek near the Village of Killbuck, Ohio, were created by the U.S. Geological Survey (USGS), in cooperation with Holmes County, Ohio. The inundation maps depict estimates of the areal extent of flooding corresponding to water levels (stages) at the USGS streamgage Killbuck Creek near Killbuck (03139000) and were completed as part of an update to Federal Emergency Management Agency Flood-Insurance Study. The maps were provided to the National Weather Service (NWS) for incorporation into a Web-based flood-warning system that can be used in conjunction with NWS flood-forecast data to show areas of predicted flood inundation associated with forecasted flood-peak stages. The digital maps also have been submitted for inclusion in the data libraries of the USGS interactive Flood Inundation Mapper. Data from the streamgage can be used by emergency-management personnel, in conjunction with the flood-inundation maps, to help determine a course of action when flooding is imminent. Flood profiles for selected reaches were prepared by calibrating a steady-state step-backwater model to an established streamgage rating curve. The step-backwater model then was used to determine water-surface-elevation profiles for 10 flood stages at the streamgage with corresponding streamflows ranging from approximately the 50- to 0.2-percent annual exceedance probabilities. The computed flood profiles were used in combination with digital elevation data to delineate flood-inundation areas.

An operational procedure for rapid flood risk assessment in Europe

NASA Astrophysics Data System (ADS)

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.

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

NASA Astrophysics Data System (ADS)

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.

Synoptic-scale atmospheric conditions associated with flash flooding in watersheds of the Catskill Mountains, New York, USA

NASA Astrophysics Data System (ADS)

Teale, N. G.; Quiring, S. M.

2015-12-01

Understanding flash flooding is important in unfiltered watersheds, such as portions of the New York City water supply system (NYCWSS), as water quality is degraded by turbidity associated with flooding. To further understand flash flooding in watersheds of the NYCWSS, synoptic-scale atmospheric conditions most frequently associated with flash flooding between 1987 and 2013 were examined. Flash floods were identified during this time period using USGS 15-minute discharge data at the Esopus Creek near Allaben, NY and Neversink River at Claryville, NY gauges. Overall, 25 flash floods were detected, occurring over 17 separate flash flood days. These flash flood days were compared to the days on which flash flood warnings encompassing the study area was issued by the National Weather Service. The success rate for which the flash flood warnings for Ulster County coincided with flash flood in the study watershed was 0.09, demonstrating the highly localized nature of flash flooding in the Catskill Mountain region. The synoptic-scale atmospheric patterns influencing the study area were characterized by a principal component analysis and k-means clustering of NCEP/NCAR 500 mb geopotential height reanalysis data. This procedure was executed in Spatial Synoptic Typer Tools 4.0. While 17 unique synoptic patterns were identified, only 3 types were strongly associated with flash flooding events. A strong southwesterly flow suggesting advection of moisture from the Atlantic Ocean and Gulf of Mexico is shown in composites of these 3 types. This multiscalar study thereby links flash flooding in the NYCWSS with synoptic-scale atmospheric circulation.Understanding flash flooding is important in unfiltered watersheds, such as portions of the New York City water supply system (NYCWSS), as water quality is degraded by turbidity associated with flooding. To further understand flash flooding in watersheds of the NYCWSS, synoptic-scale atmospheric conditions most frequently associated with flash flooding between 1987 and 2013 were examined. Flash floods were identified during this time period using USGS 15-minute discharge data at the Esopus Creek near Allaben, NY and Neversink River at Claryville, NY gauges. Overall, 25 flash floods were detected, occurring over 17 separate flash flood days. These flash flood days were compared to the days on which flash flood warnings encompassing the study area was issued by the National Weather Service. The success rate for which the flash flood warnings for Ulster County coincided with flash flood in the study watershed was 0.09, demonstrating the highly localized nature of flash flooding in the Catskill Mountain region. The synoptic-scale atmospheric patterns influencing the study area were characterized by a principal component analysis and k-means clustering of NCEP/NCAR 500 mb geopotential height reanalysis data. This procedure was executed in Spatial Synoptic Typer Tools 4.0. While 17 unique synoptic patterns were identified, only 3 types were strongly associated with flash flooding events. A strong southwesterly flow suggesting advection of moisture from the Atlantic Ocean and Gulf of Mexico is shown in composites of these 3 types. This multiscalar study thereby links flash flooding in the NYCWSS with synoptic-scale atmospheric circulation.

An Exploration of the Importance of Flood Heterogeneity for Regionalization in Arizona using the Expected Moments Algorithm

NASA Astrophysics Data System (ADS)

Zamora-Reyes, D.; Hirschboeck, K. K.; Paretti, N. V.

2012-12-01

Bulletin 17B (B17B) has prevailed for 30 years as the standard manual for determining flood frequency in the United States. Recently proposed updates to B17B include revising the issue of flood heterogeneity, and improving flood estimates by using the Expected Moments Algorithm (EMA) which can better address low outliers and accommodate information on historical peaks. Incorporating information on mixed populations, such as flood-causing mechanisms, into flood estimates for regions that have noticeable flood heterogeneity can be statistically challenging when systematic flood records are short. The problem magnifies when the population sample size is reduced by decomposing the record, especially if multiple flood mechanisms are involved. In B17B, the guidelines for dealing with mixed populations focus primarily on how to rule out any need to perform a mixed-population analysis. However, in some regions mixed flood populations are critically important determinants of regional flood frequency variations and should be explored from this perspective. Arizona is an area with a heterogeneous mixture of flood processes due to: warm season convective thunderstorms, cool season synoptic-scale storms, and tropical cyclone-enhanced convective activity occurring in the late summer or early fall. USGS station data throughout Arizona was compiled into a database and each flood peak (annual and partial duration series) was classified according to its meteorological cause. Using these data, we have explored the role of flood heterogeneity in Arizona flood estimates through composite flood frequency analysis based on mixed flood populations using EMA. First, for selected stations, the three flood-causing populations were separated out from the systematic annual flood series record and analyzed individually. Second, to create composite probability curves, the individual curves for each of the three populations were generated and combined using Crippen's (1978) composite probability equations for sites that have two or more independent flood populations. Finally, the individual probability curves generated for each of the three flood-causing populations were compared with both the site's composite probability curve and the standard B17B curve to explore the influence of heterogeneity using the 100-year and 200-year flood estimates as a basis of comparison. Results showed that sites located in southern Arizona and along the abrupt elevation transition zone of the Mogollon Rim exhibit a better fit to the systematic data using their composite probability curves than the curves derived from standard B17B analysis. Synoptic storm floods and tropical cyclone-enhanced floods had the greatest influence on 100-year and 200-year flood estimates. This was especially true in southern Arizona, even though summer convective floods are much more frequent and therefore dominate the composite curve. Using the EMA approach also influenced our results because all possible low outliers were censored by the built-in Multiple Grubbs-Beck Test, providing a better fit to the systematic data in the upper probabilities. In conclusion, flood heterogeneity can play an important role in regional flood frequency variations in Arizona and that understanding its influence is important when making projections about future flood variations.

Preparing for floods: flood forecasting and early warning

NASA Astrophysics Data System (ADS)

Cloke, Hannah

2016-04-01

Flood forecasting and early warning has continued to stride ahead in strengthening the preparedness phases of disaster risk management, saving lives and property and reducing the overall impact of severe flood events. For example, continental and global scale flood forecasting systems such as the European Flood Awareness System and the Global Flood Awareness System provide early information about upcoming floods in real time to various decisionmakers. Studies have found that there are monetary benefits to implementing these early flood warning systems, and with the science also in place to provide evidence of benefit and hydrometeorological institutional outlooks warming to the use of probabilistic forecasts, the uptake over the last decade has been rapid and sustained. However, there are many further challenges that lie ahead to improve the science supporting flood early warning and to ensure that appropriate decisions are made to maximise flood preparedness.

Karst flash floods: an example from the Dinaric karst (Croatia)

NASA Astrophysics Data System (ADS)

Bonacci, O.; Ljubenkov, I.; Roje-Bonacci, T.

2006-03-01

Flash floods constitute one of the deadliest and costliest natural disasters worldwide. This paper explains the karst flash flood phenomenon, which represents a special kind of flash flood. As the majority of flash floods karst flash floods are caused by intensive short-term precipitation in an area whose surface rarely exceeds a few square kilometres. The characteristics of all flash floods are their short duration, small areal extent, high flood peaks and rapid flows, and heavy loss of life and property. Karst flash floods have specific characteristics due to special conditions for water circulation, which exist in karst terrains. During karst flash floods a sudden rise of groundwater levels occurs, which causes the appearance of numerous, unexpected, abundant and temporary karst springs. This paper presents in detail an example of a karst flash flood in the Marina bay (Dinaric karst region of Croatia), which occurred in December 2004.

Defining Flood Zone Transitions in Low-Gradient Coastal Regions

NASA Astrophysics Data System (ADS)

Bilskie, M. V.; Hagen, S. C.

2018-03-01

Worldwide, coastal, and deltaic communities are susceptible to flooding from the individual and combined effects of rainfall excess and astronomic tide and storm surge inundation. Such flood events are a present (and future) cause of concern as observed from recent storms such as the 2016 Louisiana flood and Hurricanes Harvey, Irma, and Maria. To assess flood risk across coastal landscapes, it is advantageous to first delineate flood transition zones, which we define as areas susceptible to hydrologic and coastal flooding and their collective interaction. We utilize numerical simulations combining rainfall excess and storm surge for the 2016 Louisiana flood to describe a flood transition zone for southeastern Louisiana. We show that the interaction of rainfall excess with coastal surge is nonlinear and less than the superposition of their individual components. Our analysis provides a foundation to define flooding zones across coastal landscapes throughout the world to support flood risk assessments.

Study on reservoir time-varying design flood of inflow based on Poisson process with time-dependent parameters

NASA Astrophysics Data System (ADS)

Li, Jiqing; Huang, Jing; Li, Jianchang

2018-06-01

The time-varying design flood can make full use of the measured data, which can provide the reservoir with the basis of both flood control and operation scheduling. This paper adopts peak over threshold method for flood sampling in unit periods and Poisson process with time-dependent parameters model for simulation of reservoirs time-varying design flood. Considering the relationship between the model parameters and hypothesis, this paper presents the over-threshold intensity, the fitting degree of Poisson distribution and the design flood parameters are the time-varying design flood unit period and threshold discriminant basis, deduced Longyangxia reservoir time-varying design flood process at 9 kinds of design frequencies. The time-varying design flood of inflow is closer to the reservoir actual inflow conditions, which can be used to adjust the operating water level in flood season and make plans for resource utilization of flood in the basin.

7 CFR 1788.3 - Flood insurance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 12 2010-01-01 2010-01-01 false Flood insurance. 1788.3 Section 1788.3 Agriculture... Insurance Requirements § 1788.3 Flood insurance. (a) Borrowers shall purchase and maintain flood insurance for buildings in flood hazard areas to the extent available and required under the National Flood...

44 CFR 78.6 - Flood Mitigation Plan approval process.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 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...

44 CFR 78.6 - Flood Mitigation Plan approval process.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 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...

44 CFR 78.6 - Flood Mitigation Plan approval process.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 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...

Flood frequency analysis - the challenge of using historical data

NASA Astrophysics Data System (ADS)

Engeland, Kolbjorn

2015-04-01

Estimates of high flood quantiles are needed for many applications, .e.g. dam safety assessments are based on the 1000 years flood, whereas the dimensioning of important infrastructure requires estimates of the 200 year flood. The flood quantiles are estimated by fitting a parametric distribution to a dataset of high flows comprising either annual maximum values or peaks over a selected threshold. Since the record length of data is limited compared to the desired flood quantile, the estimated flood magnitudes are based on a high degree of extrapolation. E.g. the longest time series available in Norway are around 120 years, and as a result any estimation of a 1000 years flood will require extrapolation. One solution is to extend the temporal dimension of a data series by including information about historical floods before the stream flow was systematically gaugeded. Such information could be flood marks or written documentation about flood events. The aim of this study was to evaluate the added value of using historical flood data for at-site flood frequency estimation. The historical floods were included in two ways by assuming: (1) the size of (all) floods above a high threshold within a time interval is known; and (2) the number of floods above a high threshold for a time interval is known. We used a Bayesian model formulation, with MCMC used for model estimation. This estimation procedure allowed us to estimate the predictive uncertainty of flood quantiles (i.e. both sampling and parameter uncertainty is accounted for). We tested the methods using 123 years of systematic data from Bulken in western Norway. In 2014 the largest flood in the systematic record was observed. From written documentation and flood marks we had information from three severe floods in the 18th century and they were likely to exceed the 2014 flood. We evaluated the added value in two ways. First we used the 123 year long streamflow time series and investigated the effect of having several shorter series' which could be supplemented with a limited number of known large flood events. Then we used the three historical floods from the 18th century combined with the whole and subsets of the 123 years of systematic observations. In the latter case several challenges were identified: i) The possibility to transfer water levels to river streamflows due to man made changes in the river profile, (ii) The stationarity of the data might be questioned since the three largest historical floods occurred during the "little ice age" with different climatic conditions compared to today.

Paleohydrology of flash floods in small desert watersheds in western Arizona

NASA Astrophysics Data System (ADS)

House, P. Kyle; Baker, Victor R.

2001-06-01

In this study, geological, historical, and meteorological data were combined to produce a regional chronology of flood magnitude and frequency in nine small basins (7-70 km2). The chronology spans more than 1000 years and demonstrates that detailed records of flood magnitude and frequency can be compiled in arid regions with little to no conventional hydrologic information. The recent (i.e., post-1950) flood history was evaluated by comparing a 50-year series of aerial photographs with precipitation data, ages of flood-transported beer cans, anthropogenic horizons in flood sediments, postbomb 14C dates on flotsam, and anecdotal accounts. Stratigraphic analysis of paleoflood deposits extended the regional flood record in time, and associated flood magnitudes were determined by incorporating relict high-water evidence into a hydraulic model. The results reveal a general consistency among the magnitudes of the largest floods in the historical and the paleoflood records and indicate that the magnitudes and relative frequencies of actual large floods are at variance with "100-year" flood magnitudes predicted by regional flood frequency models. This suggests that the predictive equations may not be appropriate for regulatory, management, or design purposes in the absence of additional, real data on flooding. Augmenting conventional approaches to regional flood magnitude and frequency analysis with real information derived from the alternative methods described here is a viable approach to improving assessments of regional flood characteristics in sparsely gaged desert areas.

Analyzing Future Flooding under Climate Change Scenario using CMIP5 Streamflow Data

NASA Astrophysics Data System (ADS)

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.

Proteomic analysis of soybean hypocotyl during recovery after flooding stress.

PubMed

Khan, Mudassar Nawaz; Sakata, Katsumi; Komatsu, Setsuko

2015-05-21

Soybean is a nutritionally important crop, but exhibits reduced growth and yields under flooding stress. To investigate soybean responses during post-flooding recovery, a gel-free proteomic technique was used to examine the protein profile in the hypocotyl. Two-day-old soybeans were flooded for 2 days and hypocotyl was collected under flooding and during the post-flooding recovery period. A total of 498 and 70 proteins were significantly changed in control and post-flooding recovering soybeans, respectively. Based on proteomic and clustering analyses, three proteins were selected for mRNA expression and enzyme activity assays. Pyruvate kinase was increased under flooding, but gradually decreased during post-flooding recovery period at protein abundance, mRNA, and enzyme activity levels. Nucleotidylyl transferase was decreased under flooding and increased during post-flooding recovery at both mRNA expression and enzyme activity levels. Beta-ketoacyl reductase 1 was increased under flooding and decreased during recovery at protein abundance and mRNA expression levels, but its enzyme activity gradually increased during the post-flooding recovery period. These results suggest that pyruvate kinase, nucleotidylyl transferase, and beta-ketoacyl reductase play key roles in post-flooding recovery in soybean hypocotyl by promoting glycolysis for the generation of ATP and regulation of secondary metabolic pathways. This study analyzed post-flooding recovery response mechanisms in soybean hypocotyl, which is a model organ for studying secondary growth, using a gel-free proteomic technique. Mass spectrometry analysis of proteins extracted from soybean hypocotyls identified 20 common proteins between control and flooding-stressed soybeans that changed significantly in abundance over time. The hypocotyl proteins that changed during post-flooding recovery were assigned to protein, development, secondary metabolism, and glycolysis categories. The analysis revealed that three proteins, pyruvate kinase, nucleotidylyl transferase, and beta-ketoacyl reductase, were increased in hypocotyl under flooding conditions and during post-flooding recovery. The proteins are involved in glycolysis, nucleotide synthesis and amino acid activation, and complex fatty acid biosynthesis. Copyright © 2015 Elsevier B.V. All rights reserved.

Floods of 1971 and 1972 on Glover Creek and Little River in southeastern Oklahoma

USGS Publications Warehouse

Thomas, Wilbert O.; Corley, Robert K.

1973-01-01

Heavy rains of December 9-10, 1971, and Oct. 30-31, 1972, caused outstanding floods on Glover Creek and Little River in McCurtain County in southeastern Oklahoma. This report presents hydrologic data that document the extent of flooding, flood profiles, and frequency of flooding on reaches of both streams. The data presented provide a technical basis for formulating effective flood-plain zoning that will minimize existing and future flood problems. The report also can be useful for locating waste-disposal and water-treatment facilities, and for the development of recreational areas. The area studied includes the reach of Little River on the Garvin and Idabel 7 1/2-minute quadrangles (sheet 1) and the reach of Glover Creek on the southwest quarter of the Golden 15-minute quadrangle (sheet 2). The flood boundaries delineated on the maps are the limits of flooding during the December 1971 and October 1972 floods. Any attempt to delineate the flood boundaries on streams in the study area other than Glover Creek and Little River was considered to be beyond the scope of this report. The general procedure used in defining the flood boundaries was to construct the flood profiles from high-water marks obtained by field surveys and by records at three stream-gaging stations (two on Little River and one on Glover Creek.). The extent of flooding was delineated on the topographic maps by using the flood profiles to define the flood elevations at various points along the channel and locating the elevations on the map by interpolating between contours (lines of equal ground elevation). In addition, flood boundaries were defined in places by field survey, aerial photographs, and information from local residents. The accuracy of the flood boundaries is consistent with the scale and contour interval of the maps (1 inch = 2,000 feet; contour interval 10 and 20 feet), which means the flood boundaries are drawn as accurately as possible on maps having 10- and 20-foot contour intervals.

Going beyond the flood insurance rate map: insights from flood hazard map co-production

NASA Astrophysics Data System (ADS)

Luke, Adam; Sanders, Brett F.; Goodrich, Kristen A.; Feldman, David L.; Boudreau, Danielle; Eguiarte, Ana; Serrano, Kimberly; Reyes, Abigail; Schubert, Jochen E.; AghaKouchak, Amir; Basolo, Victoria; Matthew, Richard A.

2018-04-01

Flood hazard mapping in the United States (US) is deeply tied to the National Flood Insurance Program (NFIP). Consequently, publicly available flood maps provide essential information for insurance purposes, but they do not necessarily provide relevant information for non-insurance aspects of flood risk management (FRM) such as public education and emergency planning. Recent calls for flood hazard maps that support a wider variety of FRM tasks highlight the need to deepen our understanding about the factors that make flood maps useful and understandable for local end users. In this study, social scientists and engineers explore opportunities for improving the utility and relevance of flood hazard maps through the co-production of maps responsive to end users' FRM needs. Specifically, two-dimensional flood modeling produced a set of baseline hazard maps for stakeholders of the Tijuana River valley, US, and Los Laureles Canyon in Tijuana, Mexico. Focus groups with natural resource managers, city planners, emergency managers, academia, non-profit, and community leaders refined the baseline hazard maps by triggering additional modeling scenarios and map revisions. Several important end user preferences emerged, such as (1) legends that frame flood intensity both qualitatively and quantitatively, and (2) flood scenario descriptions that report flood magnitude in terms of rainfall, streamflow, and its relation to an historic event. Regarding desired hazard map content, end users' requests revealed general consistency with mapping needs reported in European studies and guidelines published in Australia. However, requested map content that is not commonly produced included (1) standing water depths following the flood, (2) the erosive potential of flowing water, and (3) pluvial flood hazards, or flooding caused directly by rainfall. We conclude that the relevance and utility of commonly produced flood hazard maps can be most improved by illustrating pluvial flood hazards and by using concrete reference points to describe flooding scenarios rather than exceedance probabilities or frequencies.

Integrating Local Experiential and Hydrometeorological Data to Understand Knowledge Uncertainties and to Build Resilience to Flooding in Two Puerto Rican Communities.

NASA Astrophysics Data System (ADS)

Ramsey, M.; Nytch, C. J.; Branoff, B.

2016-12-01

Socio-hydrological studies that explore feedbacks between social and biophysical processes related to flood risk can help managers identify strategies that increase a community's freshwater security. However, knowledge uncertainty due to coarse spatio-temporal coverage of hydrological monitoring data, missing riverine discharge and precipitation records, assumptions of flood risk models, and effects of urbanization, can limit the ability of these studies to isolate hydrological responses to social drivers of flooding and a changing climate. Local experiential knowledge can provide much needed information about 1) actual flood spatio-temporal patterns, 2) human impacts and perceptions of flood events, and 3) mechanisms to validate flood risk studies and understand key social elements of the system. We addressed these knowledge gaps by comparing the location and timing of flood events described in resident interviews and resident drawn maps (total = 97) from two San Juan communities with NOAA and USGS precipitation and riverine discharge data archives, and FEMA flood maps. Analyses of five focal flood events revealed 1) riverine monitoring data failed to record a major flood event caused by localized blockage of the river, 2) residents did not mention multiple extreme riverine discharge events, 3) resident and FEMA flood maps matched closely but resident maps provided finer spatial information about frequency of flooding, and 4) only a small percentage of residents remembered the dates of flood events. Local knowledge provided valuable social data about flood impacts on human economic and physical/psychological wellbeing, perceptions about factors causing flooding, and what residents use as sources of flood information. A simple mechanism or tool for residents to record their flood experiences in real-time will address the uncertainties in local knowledge and improve social memory. The integration of local experiential knowledge with simulated and empirical hydro-meteorological data can be a powerful approach to increase the quality of socio-hydrological studies about flooding and freshwater security.

Development of a flood-warning network and flood-inundation mapping for the Blanchard River in Ottawa, Ohio

USGS Publications Warehouse

Whitehead, Matthew T.

2011-01-01

Digital flood-inundation maps of the Blanchard River in Ottawa, Ohio, were created by the U.S. Geological Survey (USGS) in cooperation with the U.S. Department of Agriculture, Natural Resources Conservation Service and the Village of Ottawa, Ohio. The maps, which correspond to water levels (stages) at the USGS streamgage at Ottawa (USGS streamgage site number 04189260), were provided to the National Weather Service (NWS) for incorporation into a Web-based flood-warning Network that can be used in conjunction with NWS flood-forecast data to show areas of predicted flood inundation associated with forecasted flood-peak stages. Flood profiles were computed by means of a step-backwater model calibrated to recent field measurements of streamflow. The step-backwater model was then used to determine water-surface-elevation profiles for 12 flood stages with corresponding streamflows ranging from less than the 2-year and up to nearly the 500-year recurrence-interval flood. The computed flood profiles were used in combination with digital elevation data to delineate flood-inundation areas. Maps of the Village of Ottawa showing flood-inundation areas overlain on digital orthophotographs are presented for the selected floods. As part of this flood-warning network, the USGS upgraded one streamgage and added two new streamgages, one on the Blanchard River and one on Riley Creek, which is tributary to the Blanchard River. The streamgage sites were equipped with both satellite and telephone telemetry. The telephone telemetry provides dual functionality, allowing village officials and the public to monitor current stage conditions and enabling the streamgage to call village officials with automated warnings regarding flood stage and/or predetermined rates of stage increase. Data from the streamgages serve as a flood warning that emergency management personnel can use in conjunction with the flood-inundation maps by to determine a course of action when flooding is imminent.

Extent and frequency of floods on Delaware River in vicinity of Belvidere, New Jersey

USGS Publications Warehouse

Farlekas, George M.

1966-01-01

A stream overflowing its banks is a natural phenomenon. This natural phenomenon of flooding has occurred on the Delaware River in the past and will occur in the future. T' o resulting inundation of large areas can cause property damage, business losses and possible loss of life, and may result in emergency costs for protection, rescue, and salvage work. For optimum development of the river valley consistent with the flood risk, an evaluation of flood conditions is necessary. Basic data and the interpretation of the data on the regimen of the streams, particularly the magnitude of floods to be expected, the frequency of their occurrence, and the areas inundated, are essential for planning and development of flood-prone areas.This report presents information relative to the extent, depth, and frequency of floods on the Delaware River and its tributaries in the vicinity of Belvidere, N.J. Flooding on the tributaries detailed in the report pertains only to the effect of backwater from the Delaware River. Data are presented for several past floods with emphasis given to the floods of August 19, 1955 and May 24, 1942. In addition, information is given for a hypothetical flood based on the flood of August 19, 1955 modified by completed (since 1955) and planned flood-control works.By use of relations presented in this report the extent, depth, and frequency of flooding can be estimated for any site along the reach of the Delaware River under study. Flood data and the evaluation of the data are presented so that local and regional agencies, organizations, and individuals may have a technical basis for making decisions on the use of flood-prone areas. The Delaware River Basin Commission and the U.S. Geological Survey regard this program of flood-plain inundation studies as a positive step toward flood-damage prevention. Flood-plain inundation studies, when followed by appropriate land-use regulations, are a valuable and economical supplement to physical works for flood control, such as dams and levees. Both physical works and flood-plain regulations are included in the comprehensive plans for development of the Delaware River basin.Recommendations for land use, or suggestions for limitations of land use, are not made herein. Other reports on recommended general use and regulation of land in flood-prone areas are available (Dola, 1961; White, 1961; American Society of Civil Engineers Task Force on Flood Plain Regulations, 1962; and Goddard, 1963). The primary responsibility for planning for the optimum land use in the flood plain and the implementation of flood-plain zoning or other regulations to achieve such optimum use rest with the state and local interests. The preparation of this report was undertaken after consultation with representatives of the Lehigh-Northampton Counties, Pennsylvania, Joint Planning Commission and the Warren County, New Jersey, Regional Planning Board and after both had demonstrated their need for flood-plain information and their willingness to consider flood-plain regulations.

44 CFR 64.3 - Flood Insurance Maps.

Code of Federal Regulations, 2011 CFR

2011-10-01

... flood hazard that results from the decertification of a previously accredited flood protection system that is determined to be in the process of being restored to provide base flood protection V Area of... tidal floods (coastal high hazard area) V1-30, VE Area of special flood hazards, with water surface...

44 CFR 78.6 - Flood Mitigation Plan approval process.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Flood Mitigation Plan approval..., 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...

Proteomic analysis of the flooding tolerance mechanism in mutant soybean.

PubMed

Komatsu, Setsuko; Nanjo, Yohei; Nishimura, Minoru

2013-02-21

Flooding stress of soybean is a serious problem because it reduces growth; however, flooding-tolerant cultivars have not been identified. To analyze the flooding tolerance mechanism of soybean, the flooding-tolerant mutant was isolated and analyzed using a proteomic technique. Flooding-tolerance tests were repeated five times using gamma-ray irradiated soybeans, whose root growth (M6 stage) was not suppressed even under flooding stress. Two-day-old wild-type and mutant plants were subjected to flooding stress for 2days, and proteins were identified using a gel-based proteomic technique. In wild-type under flooding stress, levels of proteins related to development, protein synthesis/degradation, secondary metabolism, and the cell wall changed; however, these proteins did not markedly differ in the mutant. In contrast, an increased number of fermentation-related proteins were identified in the mutant under flooding stress. The root tips of mutant plants were not affected by flooding stress, even though the wild-type plants had damaged root. Alcohol dehydrogenase activity in the mutant increased at an early stage of flooding stress compared with that of the wild-type. Taken together, these results suggest that activation of the fermentation system in the early stages of flooding may be an important factor for the acquisition of flooding tolerance in soybean. Copyright © 2012 Elsevier B.V. All rights reserved.

Timing of floods in southeastern China: Seasonal properties and potential causes

NASA Astrophysics Data System (ADS)

Zhang, Qiang; Gu, Xihui; Singh, Vijay P.; Shi, Peijun; Luo, Ming

2017-09-01

Flood hazards and flood risks in southeastern China have been causing increasing concerns due to dense population and highly-developed economy. This study attempted to address changes of seasonality, timing of peak floods and variability of occurrence date of peak floods using circular statistical methods and the modified Mann-Kendall trend detection method. The causes of peak flood changes were also investigated. Results indicated that: (1) floods were subject to more seasonality and temporal clustering when compared to precipitation extremes. However, seasonality of floods and extreme precipitation was subject to spatial heterogeneity in northern Guangdong. Similar changing patterns of peak floods and extreme precipitation were found in coastal regions; (2) significant increasing/decreasing seasonality, but no confirmed spatial patterns, were observed for peak floods and extreme precipitation. Peak floods in northern Guangdong province had decreasing variability, but had larger variability in coastal regions; (3) tropical cyclones had remarkable impacts on extreme precipitation changes in coastal regions of southeastern China, and peak floods as well. The landfalling of tropical cyclones was decreasing and concentrated during June-September; this is the major reason for earlier but enhanced seasonality of peak floods in coastal regions. This study sheds new light on flood behavior in coastal regions in a changing environment.

The Importance of Studying Past Extreme Floods to Prepare for Uncertain Future Extremes

NASA Astrophysics Data System (ADS)

Burges, S. J.

2016-12-01

Hoyt and Langbein, 1955 in their book `Floods' wrote: " ..meteorologic and hydrologic conditions will combine to produce superfloods of unprecedented magnitude. We have every reason to believe that in most rivers past floods may not be an accurate measure of ultimate flood potentialities. It is this superflood with which we are always most concerned". I provide several examples to offer some historical perspective on assessing extreme floods. In one example, flooding in the Miami Valley, OH in 1913 claimed 350 lives. The engineering and socio-economic challenges facing the Morgan Engineering Co in how to mitigate against future flood damage and loss of life when limited information was available provide guidance about ways to face an uncertain hydroclimate future, particularly one of a changed climate. A second example forces us to examine mixed flood populations and illustrates the huge uncertainty in assigning flood magnitude and exceedance probability to extreme floods in such cases. There is large uncertainty in flood frequency estimates; knowledge of the total flood hydrograph, not the peak flood flow rate alone, is what is needed for hazard mitigation assessment or design. Some challenges in estimating the complete flood hydrograph in an uncertain future climate, including demands on hydrologic models and their inputs, are addressed.

Hazards of Extreme Weather: Flood Fatalities in Texas

NASA Astrophysics Data System (ADS)

Sharif, H. O.; Jackson, T.; Bin-Shafique, S.

2009-12-01

The Federal Emergency Management Agency (FEMA) considers flooding “America’s Number One Natural Hazard”. Despite flood management efforts in many communities, U.S. flood damages remain high, due, in large part, to increasing population and property development in flood-prone areas. Floods are the leading cause of fatalities related to natural disasters in Texas. Texas leads the nation in flash flood fatalities. There are three times more fatalities in Texas (840) than the following state Pennsylvania (265). This study examined flood fatalities that occurred in Texas between 1960 and 2008. Flood fatality statistics were extracted from three sources: flood fatality databases from the National Climatic Data Center, the Spatial Hazard Event and Loss Database for the United States, and the Texas Department of State Health Services. The data collected for flood fatalities include the date, time, gender, age, location, and weather conditions. Inconsistencies among the three databases were identified and discussed. Analysis reveals that most fatalities result from driving into flood water (about 65%). Spatial analysis indicates that more fatalities occurred in counties containing major urban centers. Hydrologic analysis of a flood event that resulted in five fatalities was performed. A hydrologic model was able to simulate the water level at a location where a vehicle was swept away by flood water resulting in the death of the driver.

On the objective identification of flood seasons

NASA Astrophysics Data System (ADS)

Cunderlik, Juraj M.; Ouarda, Taha B. M. J.; BobéE, Bernard

2004-01-01

The determination of seasons of high and low probability of flood occurrence is a task with many practical applications in contemporary hydrology and water resources management. Flood seasons are generally identified subjectively by visually assessing the temporal distribution of flood occurrences and, then at a regional scale, verified by comparing the temporal distribution with distributions obtained at hydrologically similar neighboring sites. This approach is subjective, time consuming, and potentially unreliable. The main objective of this study is therefore to introduce a new, objective, and systematic method for the identification of flood seasons. The proposed method tests the significance of flood seasons by comparing the observed variability of flood occurrences with the theoretical flood variability in a nonseasonal model. The method also addresses the uncertainty resulting from sampling variability by quantifying the probability associated with the identified flood seasons. The performance of the method was tested on an extensive number of samples with different record lengths generated from several theoretical models of flood seasonality. The proposed approach was then applied on real data from a large set of sites with different flood regimes across Great Britain. The results show that the method can efficiently identify flood seasons from both theoretical and observed distributions of flood occurrence. The results were used for the determination of the main flood seasonality types in Great Britain.

Fews-Risk: A step towards risk-based flood forecasting

NASA Astrophysics Data System (ADS)

Bachmann, Daniel; Eilander, Dirk; de Leeuw, Annemargreet; Diermanse, Ferdinand; Weerts, Albrecht; de Bruijn, Karin; Beckers, Joost; Boelee, Leonore; Brown, Emma; Hazlewood, Caroline

2015-04-01

Operational flood prediction and the assessment of flood risk are important components of flood management. Currently, the model-based prediction of discharge and/or water level in a river is common practice for operational flood forecasting. Based on the prediction of these values decisions about specific emergency measures are made within operational flood management. However, the information provided for decision support is restricted to pure hydrological or hydraulic aspects of a flood. Information about weak sections within the flood defences, flood prone areas and assets at risk in the protected areas are rarely used in a model-based flood forecasting system. This information is often available for strategic planning, but is not in an appropriate format for operational purposes. The idea of FEWS-Risk is the extension of existing flood forecasting systems with elements of strategic flood risk analysis, such as probabilistic failure analysis, two dimensional flood spreading simulation and the analysis of flood impacts and consequences. Thus, additional information is provided to the decision makers, such as: • Location, timing and probability of failure of defined sections of the flood defence line; • Flood spreading, extent and hydraulic values in the hinterland caused by an overflow or a breach flow • Impacts and consequences in case of flooding in the protected areas, such as injuries or casualties and/or damages to critical infrastructure or economy. In contrast with purely hydraulic-based operational information, these additional data focus upon decision support for answering crucial questions within an operational flood forecasting framework, such as: • Where should I reinforce my flood defence system? • What type of action can I take to mend a weak spot in my flood defences? • What are the consequences of a breach? • Which areas should I evacuate first? This presentation outlines the additional required workflows towards risk-based flood forecasting systems. In a cooperation between HR Wallingford and Deltares, the extended workflows are being integrated into the Delft-FEWS software system. Delft-FEWS provides modules for managing the data handling and forecasting process. Results of a pilot study that demonstrates the new tools are presented. The value of the newly generated information for decision support during a flood event is discussed.

Identification of flood-rich and flood-poor periods in flood series

NASA Astrophysics Data System (ADS)

Mediero, Luis; Santillán, David; Garrote, Luis

2015-04-01

Recently, a general concern about non-stationarity of flood series has arisen, as changes in catchment response can be driven by several factors, such as climatic and land-use changes. Several studies to detect trends in flood series at either national or trans-national scales have been conducted. Trends are usually detected by the Mann-Kendall test. However, the results of this test depend on the starting and ending year of the series, which can lead to different results in terms of the period considered. The results can be conditioned to flood-poor and flood-rich periods located at the beginning or end of the series. A methodology to identify statistically significant flood-rich and flood-poor periods is developed, based on the comparison between the expected sampling variability of floods when stationarity is assumed and the observed variability of floods in a given series. The methodology is applied to a set of long series of annual maximum floods, peaks over threshold and counts of annual occurrences in peaks over threshold series observed in Spain in the period 1942-2009. Mediero et al. (2014) found a general decreasing trend in flood series in some parts of Spain that could be caused by a flood-rich period observed in 1950-1970, placed at the beginning of the flood series. The results of this study support the findings of Mediero et al. (2014), as a flood-rich period in 1950-1970 was identified in most of the selected sites. References: Mediero, L., Santillán, D., Garrote, L., Granados, A. Detection and attribution of trends in magnitude, frequency and timing of floods in Spain, Journal of Hydrology, 517, 1072-1088, 2014.

Process-based model with flood control measures towards more realistic global flood modeling

NASA Astrophysics Data System (ADS)

Tang, Q.; Zhang, X.; Wang, Y.; Mu, M.; Lv, A.; Li, Z.

2017-12-01

In the profoundly human-influenced era, the Anthropocene, increased amount of land was developed in flood plains and many flood control measures were implemented to protect people and infrastructures placed in the flood-prone areas. These human influences (for example, dams and dykes) have altered peak streamflow and flood risk, and are already an integral part of flood. However, most of the process-based flood models have yet to taken into account the human influences. In this study, we used a hydrological model together with an advanced hydrodynamic model to assess flood risk at the Baiyangdian catchment. The Baiyangdian Lake is the largest shallow freshwater lake in North China, and it was used as a flood storage area in the past. A new development hub for the Beijing-Tianjin-Hebei economic triangle, namely the Xiongan new area, was recently established in the flood-prone area around the lake. The shuttle radar topography mission (SRTM) digital elevation model (DEMs) was used to parameterize the hydrodynamic model simulation, and the inundation estimates were compared with published flood maps and observed inundation area during the extreme historical flood events. A simple scheme was carried out to consider the impacts of flood control measures, including the reservoirs in the headwaters and the dykes to be built. By comparing model simulations with and without the influences of flood control measures, we demonstrated the importance of human influences in altering the inundated area and depth under design flood conditions. Based on the SRTM DEM and dam and reservoir data in the Global Reservoir and Dam (GRanD) database, we further discuss the potential to develop a global flood model with human influences.

Effects of a flooding event on a threatened black bear population in Louisiana

USGS Publications Warehouse

O'Connell-Goode, Kaitlin C.; Lowe, Carrie L.; Clark, Joseph D.

2014-01-01

The Louisiana black bear, Ursus americanus luteolus, is listed as threatened under the Endangered Species Act as a result of habitat loss and human-related mortality. Information on population-level responses of large mammals to flooding events is scarce, and we had a unique opportunity to evaluate the viability of the Upper Atchafalaya River Basin (UARB) black bear population before and after a significant flooding event. We began collecting black bear hair samples in 2007 for a DNA mark-recapture study to estimate abundance (N) and apparent survival (φ). In 2011, the Morganza Spillway was opened to divert floodwaters from the Mississippi River through the UARB, inundating > 50% of our study area, potentially impacting recovery of this important bear population. To evaluate the effects of this flooding event on bear population dynamics, we used a robust design multistate model to estimate changes in transition rates from the flooded area to non-flooded area (ψF→NF) before (2007–2010), during (2010–2011) and after (2011–2012) the flood. Average N across all years of study was 63.2 (SE = 5.2), excluding the year of the flooding event. Estimates of ψF→NF increased from 0.014 (SE = 0.010; meaning that 1.4% of the bears moved from the flooded area to non-flooded areas) before flooding to 0.113 (SE = 0.045) during the flood year, and then decreased to 0.028 (SE= 0.035) after the flood. Although we demonstrated a flood effect on transition rates as hypothesized, the effect was small (88.7% of the bears remained in the flooded area during flooding) and φ was unchanged, suggesting that the 2011 flooding event had minimal impact on survival and site fidelity.

A Global Geospatial Database of 5000+ Historic Flood Event Extents

NASA Astrophysics Data System (ADS)

Tellman, B.; Sullivan, J.; Doyle, C.; Kettner, A.; Brakenridge, G. R.; Erickson, T.; Slayback, D. A.

2017-12-01

A key dataset that is missing for global flood model validation and understanding historic spatial flood vulnerability is a global historical geo-database of flood event extents. Decades of earth observing satellites and cloud computing now make it possible to not only detect floods in near real time, but to run these water detection algorithms back in time to capture the spatial extent of large numbers of specific events. This talk will show results from the largest global historical flood database developed to date. We use the Dartmouth Flood Observatory flood catalogue to map over 5000 floods (from 1985-2017) using MODIS, Landsat, and Sentinel-1 Satellites. All events are available for public download via the Earth Engine Catalogue and via a website that allows the user to query floods by area or date, assess population exposure trends over time, and download flood extents in geospatial format.In this talk, we will highlight major trends in global flood exposure per continent, land use type, and eco-region. We will also make suggestions how to use this dataset in conjunction with other global sets to i) validate global flood models, ii) assess the potential role of climatic change in flood exposure iii) understand how urbanization and other land change processes may influence spatial flood exposure iv) assess how innovative flood interventions (e.g. wetland restoration) influence flood patterns v) control for event magnitude to assess the role of social vulnerability and damage assessment vi) aid in rapid probabilistic risk assessment to enable microinsurance markets. Authors on this paper are already using the database for the later three applications and will show examples of wetland intervention analysis in Argentina, social vulnerability analysis in the USA, and micro insurance in India.

Role of adventitious roots in water relations of tamarack (Larix laricina) seedlings exposed to flooding

PubMed Central

2012-01-01

Background Flooding reduces supply of oxygen to the roots affecting plant water uptake. Some flooding-tolerant tree species including tamarack (Larix laricina (Du Roi) K. Koch) produce adventitious roots in response to flooding. These roots were reported to have higher hydraulic conductivity under flooding conditions compared with non-adventitious roots. In the present study, we examined structural and functional modifications in adventitious roots of tamarack seedlings to explain their flooding tolerance. Results Seedlings were subjected to the flooding treatment for six months, which resulted in an almost complete disintegration of the existing root system and its replacement with adventitious roots. We compared gas exchange parameters and water relations of flooded plants with the plants growing in well-drained soil and examined the root structures and root water transport properties. Although flooded seedlings had lower needle chlorophyll concentrations, their stomatal conductance, net photosynthesis rates and shoot water potentials were similar to non-flooded plants, indicative of flooding tolerance. Flooded adventitious roots had higher activation energy and a higher ratio of apoplastic to cell-to-cell water flow compared with non-flooded control roots as determined with the 1-hydroxypirene 3,6,8-trisulfonic acid apoplastic tracer dye. The adventitious roots in flooded plants also exhibited retarded xylem and endodermal development and accumulated numerous starch grains in the cortex. Microscopic examination of root sections treated with the PIP1 and PIP2 antibodies revealed high immunoreactivity in the cortex of non-flooded roots, as compared with flooded roots. Conclusions Structural modifications of adventitious roots suggest increased contribution of apoplastic bypass to water flow. The reduced dependence of roots on the hypoxia-sensitive aquaporin-mediated water transport is likely among the main mechanisms allowing tamarack seedlings to maintain water balance and gas exchange under flooding conditions. PMID:22738296

Role of adventitious roots in water relations of tamarack (Larix laricina) seedlings exposed to flooding.

PubMed

Calvo-Polanco, Mónica; Señorans, Jorge; Zwiazek, Janusz J

2012-06-27

Flooding reduces supply of oxygen to the roots affecting plant water uptake. Some flooding-tolerant tree species including tamarack (Larix laricina (Du Roi) K. Koch) produce adventitious roots in response to flooding. These roots were reported to have higher hydraulic conductivity under flooding conditions compared with non-adventitious roots. In the present study, we examined structural and functional modifications in adventitious roots of tamarack seedlings to explain their flooding tolerance. Seedlings were subjected to the flooding treatment for six months, which resulted in an almost complete disintegration of the existing root system and its replacement with adventitious roots. We compared gas exchange parameters and water relations of flooded plants with the plants growing in well-drained soil and examined the root structures and root water transport properties. Although flooded seedlings had lower needle chlorophyll concentrations, their stomatal conductance, net photosynthesis rates and shoot water potentials were similar to non-flooded plants, indicative of flooding tolerance. Flooded adventitious roots had higher activation energy and a higher ratio of apoplastic to cell-to-cell water flow compared with non-flooded control roots as determined with the 1-hydroxypirene 3,6,8-trisulfonic acid apoplastic tracer dye. The adventitious roots in flooded plants also exhibited retarded xylem and endodermal development and accumulated numerous starch grains in the cortex. Microscopic examination of root sections treated with the PIP1 and PIP2 antibodies revealed high immunoreactivity in the cortex of non-flooded roots, as compared with flooded roots. Structural modifications of adventitious roots suggest increased contribution of apoplastic bypass to water flow. The reduced dependence of roots on the hypoxia-sensitive aquaporin-mediated water transport is likely among the main mechanisms allowing tamarack seedlings to maintain water balance and gas exchange under flooding conditions.

River flood seasonality in the Northeast United States and trends in annual timing

NASA Astrophysics Data System (ADS)

Collins, M. J.

2017-12-01

The New England and Mid-Atlantic regions of the Northeast United States have experienced climate-associated increases in both the magnitude and frequency of floods. However, a detailed understanding of flood seasonality across these regions, and how flood seasonality may have changed over the instrumental record, has not been established. The annual timing of river floods reflects the flood-generating mechanisms operating in a basin and many aquatic and riparian organisms are adapted to flood seasonality, as are human uses of river channels and floodplains. Changes in flood seasonality may indicate changes in flood-generating mechanisms, and their interactions, with important implications for habitats, floodplain infrastructure, and human communities. For example, changes in spring or fall flood timing may negatively or positively affect a vulnerable life stage for a migratory fish (e.g., egg setting) depending on whether floods occur more frequently before or after the life history event. In this study I apply an objective, probabilistic method for identifying flood seasons at a monthly resolution for 90 climate-sensitive watersheds in New England and the Mid-Atlantic (Hydrologic Unit Codes 01 and 02). Historical trends in flood timing during the year are also investigated. The analyses are based on partial duration flood series that are an average of 85 years long. The seasonality of flooding in these regions, and any historical changes, are considered in the context of other ongoing or expected phenological changes in the Northeast U.S. environment that affect flood generation—e.g., the timing of leaf-off/leaf-out for deciduous plants. How these factors interact will affect whether and how flood magnitudes and frequencies change in the future and associated impacts.

Statistical analysis of the uncertainty related to flood hazard appraisal

NASA Astrophysics Data System (ADS)

Notaro, Vincenza; Freni, Gabriele

2015-12-01

The estimation of flood hazard frequency statistics for an urban catchment is of great interest in practice. It provides the evaluation of potential flood risk and related damage and supports decision making for flood risk management. Flood risk is usually defined as function of the probability, that a system deficiency can cause flooding (hazard), and the expected damage, due to the flooding magnitude (damage), taking into account both the exposure and the vulnerability of the goods at risk. The expected flood damage can be evaluated by an a priori estimation of potential damage caused by flooding or by interpolating real damage data. With regard to flood hazard appraisal several procedures propose to identify some hazard indicator (HI) such as flood depth or the combination of flood depth and velocity and to assess the flood hazard corresponding to the analyzed area comparing the HI variables with user-defined threshold values or curves (penalty curves or matrixes). However, flooding data are usually unavailable or piecemeal allowing for carrying out a reliable flood hazard analysis, therefore hazard analysis is often performed by means of mathematical simulations aimed at evaluating water levels and flow velocities over catchment surface. As results a great part of the uncertainties intrinsic to flood risk appraisal can be related to the hazard evaluation due to the uncertainty inherent to modeling results and to the subjectivity of the user defined hazard thresholds applied to link flood depth to a hazard level. In the present work, a statistical methodology was proposed for evaluating and reducing the uncertainties connected with hazard level estimation. The methodology has been applied to a real urban watershed as case study.

Advancing flood risk analysis by integrating adaptive behaviour in large-scale flood risk assessments

NASA Astrophysics Data System (ADS)

Haer, T.; Botzen, W.; Aerts, J.

2016-12-01

In the last four decades the global population living in the 1/100 year-flood zone has doubled from approximately 500 million to a little less than 1 billion people. Urbanization in low lying -flood prone- cities further increases the exposed assets, such as buildings and infrastructure. Moreover, climate change will further exacerbate flood risk in the future. Accurate flood risk assessments are important to inform policy-makers and society on current- and future flood risk levels. However, these assessment suffer from a major flaw in the way they estimate flood vulnerability and adaptive behaviour of individuals and governments. Current flood risk projections commonly assume that either vulnerability remains constant, or try to mimic vulnerability through incorporating an external scenario. Such a static approach leads to a misrepresentation of future flood risk, as humans respond adaptively to flood events, flood risk communication, and incentives to reduce risk. In our study, we integrate adaptive behaviour in a large-scale European flood risk framework through an agent-based modelling approach. This allows for the inclusion of heterogeneous agents, which dynamically respond to each other and a changing environment. We integrate state-of-the-art flood risk maps based on climate scenarios (RCP's), and socio-economic scenarios (SSP's), with government and household agents, which behave autonomously based on (micro-)economic behaviour rules. We show for the first time that excluding adaptive behaviour leads to a major misrepresentation of future flood risk. The methodology is applied to flood risk, but has similar implications for other research in the field of natural hazards. While more research is needed, this multi-disciplinary study advances our understanding of how future flood risk will develop.

Cascade reservoir flood control operation based on risk grading and warning in the Upper Yellow River

NASA Astrophysics Data System (ADS)

Xuejiao, M.; Chang, J.; Wang, Y.

2017-12-01

Flood risk reduction with non-engineering measures has become the main idea for flood management. It is more effective for flood risk management to take various non-engineering measures. In this paper, a flood control operation model for cascade reservoirs in the Upper Yellow River was proposed to lower the flood risk of the water system with multi-reservoir by combining the reservoir flood control operation (RFCO) and flood early warning together. Specifically, a discharge control chart was employed to build the joint RFCO simulation model for cascade reservoirs in the Upper Yellow River. And entropy-weighted fuzzy comprehensive evaluation method was adopted to establish a multi-factorial risk assessment model for flood warning grade. Furthermore, after determining the implementing mode of countermeasures with future inflow, an intelligent optimization algorithm was used to solve the optimization model for applicable water release scheme. In addition, another model without any countermeasure was set to be a comparative experiment. The results show that the model developed in this paper can further decrease the flood risk of water system with cascade reservoirs. It provides a new approach to flood risk management by coupling flood control operation and flood early warning of cascade reservoirs.

Optimization of wetland restoration siting and zoning in flood retention areas of river basins in China: A case study in Mengwa, Huaihe River Basin

NASA Astrophysics Data System (ADS)

Zhang, Xiaolei; Song, Yuqin

2014-11-01

Wetland restoration in floodplains is an ecological solution that can address basin-wide flooding issues and minimize flooding and damages to riverine and downstream areas. High population densities, large economic outputs, and heavy reliance on water resources make flood retention and management pressing issues in China. To balance flood control and sustainable development economically, socially, and politically, flood retention areas have been established to increase watershed flood storage capacities and enhance the public welfare for the populace living in the areas. However, conflicts between flood storage functions and human habitation appear irreconcilable. We developed a site-specific methodology for identifying potential sites and functional zones for wetland restoration in a flood retention area in middle and eastern China, optimizing the spatial distribution and functional zones to maximize flood control and human and regional development. This methodology was applied to Mengwa, one of 21 flood retention areas in China's Huaihe River Basin, using nine scenarios that reflected different flood, climatic, and hydraulic conditions. The results demonstrated improved flood retention and ecological functions, as well as increased economic benefits.

Flood Hazard Mapping by Applying Fuzzy TOPSIS Method

NASA Astrophysics Data System (ADS)

Han, K. Y.; Lee, J. Y.; Keum, H.; Kim, B. J.; Kim, T. H.

2017-12-01

There are lots of technical methods to integrate various factors for flood hazard mapping. The purpose of this study is to suggest the methodology of integrated flood hazard mapping using MCDM(Multi Criteria Decision Making). MCDM problems involve a set of alternatives that are evaluated on the basis of conflicting and incommensurate criteria. In this study, to apply MCDM to assessing flood risk, maximum flood depth, maximum velocity, and maximum travel time are considered as criterion, and each applied elements are considered as alternatives. The scheme to find the efficient alternative closest to a ideal value is appropriate way to assess flood risk of a lot of element units(alternatives) based on various flood indices. Therefore, TOPSIS which is most commonly used MCDM scheme is adopted to create flood hazard map. The indices for flood hazard mapping(maximum flood depth, maximum velocity, and maximum travel time) have uncertainty concerning simulation results due to various values according to flood scenario and topographical condition. These kind of ambiguity of indices can cause uncertainty of flood hazard map. To consider ambiguity and uncertainty of criterion, fuzzy logic is introduced which is able to handle ambiguous expression. In this paper, we made Flood Hazard Map according to levee breach overflow using the Fuzzy TOPSIS Technique. We confirmed the areas where the highest grade of hazard was recorded through the drawn-up integrated flood hazard map, and then produced flood hazard map can be compared them with those indicated in the existing flood risk maps. Also, we expect that if we can apply the flood hazard map methodology suggested in this paper even to manufacturing the current flood risk maps, we will be able to make a new flood hazard map to even consider the priorities for hazard areas, including more varied and important information than ever before. Keywords : Flood hazard map; levee break analysis; 2D analysis; MCDM; Fuzzy TOPSIS Acknowlegement This research was supported by a grant (17AWMP-B079625-04) from Water Management Research Program funded by Ministry of Land, Infrastructure and Transport of Korean government.

An empirical assessment of which inland floods can be managed.

PubMed

Mogollón, Beatriz; Frimpong, Emmanuel A; Hoegh, Andrew B; Angermeier, Paul L

2016-02-01

Riverine flooding is a significant global issue. Although it is well documented that the influence of landscape structure on floods decreases as flood size increases, studies that define a threshold flood-return period, above which landscape features such as topography, land cover and impoundments can curtail floods, are lacking. Further, the relative influences of natural versus built features on floods is poorly understood. Assumptions about the types of floods that can be managed have considerable implications for the cost-effectiveness of decisions to invest in transforming land cover (e.g., reforestation) and in constructing structures (e.g., storm-water ponds) to control floods. This study defines parameters of floods for which changes in landscape structure can have an impact. We compare nine flood-return periods across 31 watersheds with widely varying topography and land cover in the southeastern United States, using long-term hydrologic records (≥20 years). We also assess the effects of built flow-regulating features (best management practices and artificial water bodies) on selected flood metrics across urban watersheds. We show that landscape features affect magnitude and duration of only those floods with return periods ≤10 years, which suggests that larger floods cannot be managed effectively by manipulating landscape structure. Overall, urban watersheds exhibited larger (270 m(3)/s) but quicker (0.41 days) floods than non-urban watersheds (50 m(3)/s and 1.5 days). However, urban watersheds with more flow-regulating features had lower flood magnitudes (154 m(3)/s), but similar flood durations (0.55 days), compared to urban watersheds with fewer flow-regulating features (360 m(3)/s and 0.23 days). Our analysis provides insight into the magnitude, duration and count of floods that can be curtailed by landscape structure and its management. Our findings are relevant to other areas with similar climate, topography, and land use, and can help ensure that investments in flood management are made wisely after considering the limitations of landscape features to regulate floods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Framework for National Flood Risk Assessment for Canada

NASA Astrophysics Data System (ADS)

Elshorbagy, A. A.; Raja, B.; Lakhanpal, A.; Razavi, S.; Ceola, S.; Montanari, A.

2016-12-01

Worldwide, floods have been identified as a standout amongst the most widely recognized catastrophic events, resulting in the loss of life and property. These natural hazards cannot be avoided, but their consequences can certainly be reduced by having prior knowledge of their occurrence and impact. In the context of floods, the terms occurrence and impact are substituted by flood hazard and flood vulnerability, respectively, which collectively define the flood risk. There is a high need for identifying the flood-prone areas and to quantify the risk associated with them. The present study aims at delivering flood risk maps, which prioritize the potential flood risk areas in Canada. The methodology adopted in this study involves integrating various available spatial datasets such as nightlights satellite imagery, land use, population and the digital elevation model, to build a flexible framework for national flood risk assessment for Canada. The flood risk framework assists in identifying the flood-prone areas and evaluating the associated risk. All these spatial datasets were brought to a common GIS platform for flood risk analysis. The spatial datasets deliver the socioeconomic and topographical information that is required for evaluating the flood vulnerability and flood hazard, respectively. Nightlights have been investigated as a tool to be used as a proxy for the human activities to identify areas with regard to economic investment. However, other datasets, including existing flood protection measures, we added to identify a realistic flood assessment framework. Furthermore, the city of Calgary was used as an example to investigate the effect of using Digital Elevation Models (DEMs) of varying resolutions on risk maps. Along with this, the risk map for the city was further enhanced by including the population data to give a social dimension to the risk map. Flood protection measures play a major role by significantly reducing the flood risk of events with a specific return period. An analysis to update the risk maps when information on protection measures is available was carried out for the city of Winnipeg, Canada. The proposed framework is a promising approach to identify and prioritize flood-prone areas, which are in need of intervention or detailed studies.

Development and application of an atmospheric-hydrologic-hydraulic flood forecasting model driven by TIGGE ensemble forecasts

NASA Astrophysics Data System (ADS)

Bao, Hongjun; Zhao, Linna

2012-02-01

A coupled atmospheric-hydrologic-hydraulic ensemble flood forecasting model, driven by The Observing System Research and Predictability Experiment (THORPEX) Interactive Grand Global Ensemble (TIGGE) data, has been developed for flood forecasting over the Huaihe River. The incorporation of numerical weather prediction (NWP) information into flood forecasting systems may increase forecast lead time from a few hours to a few days. A single NWP model forecast from a single forecast center, however, is insufficient as it involves considerable non-predictable uncertainties and leads to a high number of false alarms. The availability of global ensemble NWP systems through TIGGE offers a new opportunity for flood forecast. The Xinanjiang model used for hydrological rainfall-runoff modeling and the one-dimensional unsteady flow model applied to channel flood routing are coupled with ensemble weather predictions based on the TIGGE data from the Canadian Meteorological Centre (CMC), the European Centre for Medium-Range Weather Forecasts (ECMWF), the UK Met Office (UKMO), and the US National Centers for Environmental Prediction (NCEP). The developed ensemble flood forecasting model is applied to flood forecasting of the 2007 flood season as a test case. The test case is chosen over the upper reaches of the Huaihe River above Lutaizi station with flood diversion and retarding areas. The input flood discharge hydrograph from the main channel to the flood diversion area is estimated with the fixed split ratio of the main channel discharge. The flood flow inside the flood retarding area is calculated as a reservoir with the water balance method. The Muskingum method is used for flood routing in the flood diversion area. A probabilistic discharge and flood inundation forecast is provided as the end product to study the potential benefits of using the TIGGE ensemble forecasts. The results demonstrate satisfactory flood forecasting with clear signals of probability of floods up to a few days in advance, and show that TIGGE ensemble forecast data are a promising tool for forecasting of flood inundation, comparable with that driven by raingauge observations.

Biogeochemical and metabolic responses to the flood pulse in a semiarid floodplain

USGS Publications Warehouse

Valett, H.M.; Baker, M.A.; Morrice, J.A.; Crawford, C.S.; Molles, M.C.; Dahm, Clifford N.; Moyer, D.L.; Thibault, J.R.; Ellis, L.M.

2005-01-01

Flood pulse inundation of riparian forests alters rates of nutrient retention and organic matter processing in the aquatic ecosystems formed in the forest interior. Along the Middle Rio Grande (New Mexico, USA), impoundment and levee construction have created riparian forests that differ in their inter-flood intervals (IFIs) because some floodplains are still regularly inundated by the flood pulse (i.e., connected), while other floodplains remain isolated from flooding (i.e., disconnected). This research investigates how ecosystem responses to the flood pulse relate to forest IFI by quantifying nutrient and organic matter dynamics in the Rio Grande floodplain during three years of experimental flooding of the disconnected floodplain and during a single year of natural flooding of the connected floodplain. Surface and subsurface conditions in paired sites (control, flood) established in the two floodplain types were monitored to address metabolic and biogeochemical responses. Compared to dry controls, rates of respiration in the flooded sites increased by up to three orders of magnitude during the flood pulse. In the disconnected forest, month-long experimental floods produced widespread anoxia of four-week duration during each of the three years of flooding. In contrast, water in the connected floodplain remained well oxygenated (3-8 ppm). Material budgets for experimental floods showed the disconnected floodplain to be a sink for inorganic nitrogen and suspended solids, but a potential source of dissolved organic carbon (DOC). Compared to the main stem of the Rio Grande, flood-water on the connected floodplain contained less nitrate, but comparable concentrations of DOC, phosphate-phosphorus, and ammonium-nitrogen. Results suggest that floodplain IFI drives metabolic and biogeochemical responses during the flood pulse. Impoundment and fragmentation have altered floodplains from a mosaic of patches with variable IFI to a bimodal distribution. Relatively predictable flooding occurs in the connected forest, while inundation of the disconnected forest occurs only as the result of managed application of water. In semiarid floodplains, water is scarce except during the flood pulse. Ecosystem responses to the flood pulse are related to the IFI and other measures of flooding history that help describe spatial variation in ecosystem function.

A non-stationary cost-benefit analysis approach for extreme flood estimation to explore the nexus of 'Risk, Cost and Non-stationarity'

NASA Astrophysics Data System (ADS)

Qi, Wei

2017-11-01

Cost-benefit analysis is commonly used for engineering planning and design problems in practice. However, previous cost-benefit based design flood estimation is based on stationary assumption. This study develops a non-stationary cost-benefit based design flood estimation approach. This approach integrates a non-stationary probability distribution function into cost-benefit analysis, and influence of non-stationarity on expected total cost (including flood damage and construction costs) and design flood estimation can be quantified. To facilitate design flood selections, a 'Risk-Cost' analysis approach is developed, which reveals the nexus of extreme flood risk, expected total cost and design life periods. Two basins, with 54-year and 104-year flood data respectively, are utilized to illustrate the application. It is found that the developed approach can effectively reveal changes of expected total cost and extreme floods in different design life periods. In addition, trade-offs are found between extreme flood risk and expected total cost, which reflect increases in cost to mitigate risk. Comparing with stationary approaches which generate only one expected total cost curve and therefore only one design flood estimation, the proposed new approach generate design flood estimation intervals and the 'Risk-Cost' approach selects a design flood value from the intervals based on the trade-offs between extreme flood risk and expected total cost. This study provides a new approach towards a better understanding of the influence of non-stationarity on expected total cost and design floods, and could be beneficial to cost-benefit based non-stationary design flood estimation across the world.

River flood plains: Some observations on their formation

USGS Publications Warehouse

Wolman, M. Gordon; Leopold, Luna Bergere

1957-01-01

On many small rivers and most great rivers, the flood plain consists of channel and overbank deposits. The proportion of the latter is generally very small.Frequency studies indicate that the flood plains of many streams of different sizes flowing in diverse physiographic and climatic regions are subject to flooding about once a year.The uniform frequency of flooding of the flood-plain surface and the small amount of deposition observed in great floods (average 0.07 foot) support the conclusion that overbank deposition contributes only a minor part of the material constituting the flood plain. The relatively high velocities (1 to 4 fps) which can occur in overbank flows and the reduction in sediment concentration which often accompanies large floods may also help account for this. Although lateral migration of channels is important in controlling the elevation of the flood plain, rates of migration are extremely variable and alone cannot account for the uniform relation the flood-plain surface bears to the channel.Detailed studies of flood plains in Maryland and in North Carolina indicate that it is difficult to differentiate between channel and overbank deposits in a stratigraphic section alone.Because deposition on the flood plain does not continue indefinitely, the flood-plain surface can only be transformed into a terrace surface by some tectonic or climatic change which alters the regimen of the river and causes it to entrench itself below its established bed and associated flood plain. A terrace, then, is distinguished from a flood plain by the frequency with which each is overflowed.

Flood Extent Mapping for Namibia Using Change Detection and Thresholding with SAR

NASA Technical Reports Server (NTRS)

Long, Stephanie; Fatoyinbo, Temilola E.; Policelli, Frederick

2014-01-01

A new method for flood detection change detection and thresholding (CDAT) was used with synthetic aperture radar (SAR) imagery to delineate the extent of flooding for the Chobe floodplain in the Caprivi region of Namibia. This region experiences annual seasonal flooding and has seen a recent renewal of severe flooding after a long dry period in the 1990s. Flooding in this area has caused loss of life and livelihoods for the surrounding communities and has caught the attention of disaster relief agencies. There is a need for flood extent mapping techniques that can be used to process images quickly, providing near real-time flooding information to relief agencies. ENVISAT/ASAR and Radarsat-2 images were acquired for several flooding seasons from February 2008 to March 2013. The CDAT method was used to determine flooding from these images and includes the use of image subtraction, decision based classification with threshold values, and segmentation of SAR images. The total extent of flooding determined for 2009, 2011 and 2012 was about 542 km2, 720 km2, and 673 km2 respectively. Pixels determined to be flooded in vegetation were typically <0.5 % of the entire scene, with the exception of 2009 where the detection of flooding in vegetation was much greater (almost one third of the total flooded area). The time to maximum flooding for the 2013 flood season was determined to be about 27 days. Landsat water classification was used to compare the results from the new CDAT with SAR method; the results show good spatial agreement with Landsat scenes.

Review article: A review and critical analysis of the efforts towards urban flood risk management in the Lagos region of Nigeria

NASA Astrophysics Data System (ADS)

Nkwunonwo, U. C.; Whitworth, M.; Baily, B.

2016-02-01

Urban flooding has been and will continue to be a significant problem for many cities across the developed and developing world. Crucial to the amelioration of the effects of these floods is the need to formulate a sound flood management policy, which is driven by knowledge of the frequency and magnitude of impacts of these floods. Within the area of flood research, attempts are being made to gain a better understanding of the causes, impacts, and pattern of urban flooding. According to the United Nations office for disaster reduction (UNISDR), flood risk is conceptualized on the basis of three integral components which are frequently adopted during flood damage estimation. These components are: probability of flood hazard, the level of exposure, and vulnerabilities of elements at risk. Reducing the severity of each of these components is the objective of flood risk management under the UNISDR guideline and idea of "living with floods". On the basis of this framework, the present research reviews flood risk within the Lagos area of Nigeria over the period 1968-2012. During this period, floods have caused harm to millions of people physically, emotionally, and economically. Arguably over this period the efforts of stakeholders to address the challenges appear to have been limited by, amongst other things, a lack of reliable data, a lack of awareness amongst the population affected, and a lack of knowledge of flood risk mitigation. It is the aim of this research to assess the current understanding of flood risk and management in Lagos and to offer recommendations towards future guidance.

Floods in the Raccoon River basin, Iowa

USGS Publications Warehouse

Heinitz, Albert J.

1980-01-01

Evaluation of flood hazards, and the planning, design, and operation of various facilities on flood plains requires information on floods. This report provides information on flood stages and discharges, flood magnitude and frequency, bench mark data, and flood profiles for the Raccoon River and some of its tributaries. Ir covers the Raccoon River, the North Raccoon River to the northern boundary of Sac County and the lower reaches of the Middle and South Raccoon Rivers.

Risk reduction in a changing insurance climate: examples from the US and UK

NASA Astrophysics Data System (ADS)

Horn, Diane; McShane, Michael

2015-04-01

Coastal cities 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. Insurance can be used as a risk-sharing mechanism to encourage adaptation to sea level rise, using pricing or restrictions on availability of cover to discourage new development in flood risk areas or to encourage the uptake of flood resilience measures. We draw on flood insurance policy lessons learned from the United States and the United Kingdom to propose risk-sharing among private insurers/reinsurers, government, and policyholders to alleviate major issues of the current programs, while still maintaining a holistic approach to managing flood risk. The UK and the US are almost polar opposites in the way flood insurance is implemented. Flood insurance in the US is fully public and in the UK fully private; however, in both countries the participants feel that the established system is unsustainable. In the US, flood coverage is excluded from property policies provided by private insurers, and is only available through the National Flood Insurance Program (NFIP), with the federal government acting as insurer of last resort. Flood risk reduction has been part of the NFIP remit since the introduction of the program in 1968. Following massive payments for flood claims related primarily to Hurricanes Katrina and Sandy, the NFIP is approximately 26 billion in debt, prompting calls to bring private insurance back into the flood insurance business. Two major Congressional modifications to the NFIP in 2012 and 2014 have pushed the contradictory goals of fully risk-based, yet affordable premiums. The private market has not been significantly involved in a risk-bearing role, but that is changing as private insurers enter as competitors, which is likely to increase NFIP flood risk portfolio volatility and undermine the NFIP goal of integrated flood risk management and risk reduction. In the UK, flood coverage is available only from private insurers, and is bundled with other perils in property policies. This approach is unusual in not passing all or part of the flood risk to government, with the financial costs of floods borne entirely by the private sector. Although the UK flood insurance market will change significantly in 2015 with the introduction of Flood Re, a subsidized flood insurance pool for high-risk households, flood cover will continue to be provided solely by the private sector. Flood Re does not reduce flood loss, but spreads the risk, protecting some policyholders from the costs of flooding at the expense of others. In contrast to the NFIP, Flood Re does not provide any incentives for policyholders or communities to improve the flood resilience of their properties.

12 CFR 614.4945 - Forced placement of flood insurance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Forced placement of flood insurance. 614.4945... OPERATIONS Flood Insurance Requirements § 614.4945 Forced placement of flood insurance. If a System... not covered by flood insurance or are covered by flood insurance in an amount less than the amount...

18 CFR 801.8 - Flood plain management and protection.

Code of Federal Regulations, 2014 CFR

2014-04-01

... nonstructural nature for the protection of flood plains subject to frequent flooding. (3) Assist in the study and classification of flood prone lands to ascertain the relative risk of flooding, and establish...

18 CFR 801.8 - Flood plain management and protection.

Code of Federal Regulations, 2012 CFR

2012-04-01

... nonstructural nature for the protection of flood plains subject to frequent flooding. (3) Assist in the study and classification of flood prone lands to ascertain the relative risk of flooding, and establish...

18 CFR 801.8 - Flood plain management and protection.

Code of Federal Regulations, 2013 CFR

2013-04-01

... nonstructural nature for the protection of flood plains subject to frequent flooding. (3) Assist in the study and classification of flood prone lands to ascertain the relative risk of flooding, and establish...

Benchmarking an operational procedure for rapid flood mapping and risk assessment in Europe

NASA Astrophysics Data System (ADS)

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

2016-04-01

The development of real-time methods for rapid flood mapping and risk assessment is crucial to improve emergency response and mitigate flood impacts. This work describes the benchmarking of an operational procedure for rapid flood risk assessment based on the flood predictions issued by the European Flood Awareness System (EFAS). The daily forecasts produced for the major European river networks are translated into event-based flood hazard maps using a large map catalogue derived from high-resolution hydrodynamic simulations, based on the hydro-meteorological dataset of EFAS. Flood hazard maps are then combined with exposure and vulnerability information, and the impacts of the forecasted flood events are evaluated in near real-time in terms of flood prone areas, potential economic damage, affected population, infrastructures and cities. An extensive testing of the operational procedure is carried out using the catastrophic floods of May 2014 in Bosnia-Herzegovina, Croatia and Serbia. The reliability of the flood mapping methodology is tested against satellite-derived flood footprints, while ground-based estimations of economic damage and affected population is compared against modelled estimates. We evaluated the skill of flood hazard and risk estimations derived from EFAS flood forecasts with different lead times and combinations. The assessment includes a comparison of several alternative approaches to produce and present the information content, in order to meet the requests of EFAS users. The tests provided good results and showed the potential of the developed real-time operational procedure in helping emergency response and management.

An Agent-Based Model of Evolving Community Flood Risk.

PubMed

Tonn, Gina L; Guikema, Seth D

2018-06-01

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.

Identification of Dominant Flood Drivers across Canada

NASA Astrophysics Data System (ADS)

Singh, J.; Karmakar, S.; Ghosh, S.; Simonovic, S.; Gusain, A.

2016-12-01

In recent past, flooding has taken a devastating form causing societal, economic, and environmental losses over the Globe. Reliable information on the cause of occurrence, time, and magnitude of flood events might be useful for effective planning, design and operation of hydraulic structures to minimize losses. In the present study, we used circular statistics to understand the pattern and seasonality in flooding across Canada. A set of analyses is performed on unregulated daily stream flow data from 318 stream gage stations (procure from HYDAT database) with a record of at least 40 years between 1951-2010. Further, an attempt is also made to identify possible primary drivers of flooding across Canada. To accomplish this, daily precipitation record from 561 stations and 10 resolution snowmelt data from ECMWF ERA 20C during 1951-2010 have been used. Majority of stations reported statistically significant negative trend in flood magnitude in south western part, whereas, an increasing trend in frequency of flooding observed in south eastern part of Canada. The results show a strong evidence of regional patterns of seasonality and inter-annual variability in flooding. It is observed, about 42% of flood events occur during spring (March-May) over south eastern part of Canada and are not associated with extreme precipitation, where snowmelt is found to be primary factor for occurrence of flood events. Further, about 44% of flood events occur during summer (June-August) in southwestern region and having strong association with extreme precipitation. Additionally, we observe the negative trend in precipitation driven flood events (summer flooding) in south western part of Canada. The present study on identification of major flood drivers across Canada shows a need to examine the influence of various climate indices quantifying variation of surface temperature anomalies, which will improve flood prediction and consequently flood risk management. Keywords: Canada, Flood drivers, Flood management, Precipitation, Snowmelt

An exhaustive approach for identification of flood risk hotspots in data poor regions enforcing combined geomorphic and socio-economic indicators

NASA Astrophysics Data System (ADS)

Mohanty, M. P.; Karmakar, S.; Ghosh, S.

2017-12-01

Many countries across the Globe are victims of floods. To monitor them, various sophisticated algorithms and flood models are used by the scientific community. However, there still lies a gap to efficiently mapping flood risk. The limitations being: (i) scarcity of extensive data inputs required for precise flood modeling, (ii) fizzling performance of models in large and complex terrains (iii) high computational cost and time, and (iv) inexpertise in handling model simulations by civic bodies. These factors trigger the necessity of incorporating uncomplicated and inexpensive, yet precise approaches to identify areas at different levels of flood risk. The present study addresses this issue by utilizing various easily available, low cost data in a GIS environment for a large flood prone and data poor region. A set of geomorphic indicators of Digital Elevation Model (DEM) are analysed through linear binary classification, and are used to identify the flood hazard. The performance of these indicators is then investigated using receiver operating characteristics (ROC) curve, whereas the calibration and validation of the derived flood maps are accomplished through a comparison with dynamically coupled 1-D 2-D flood model outputs. A high degree of similarity on flood inundation proves the reliability of the proposed approach in identifying flood hazard. On the other hand, an extensive list of socio-economic indicators is selected to represent the flood vulnerability at a very finer forward sortation level using multivariate Data Envelopment Analysis (DEA). A set of bivariate flood risk maps is derived combining the flood hazard and socio-economic vulnerability maps. Given the acute problem of floods in developing countries, the proposed methodology which may be characterized by low computational cost, lesser data requirement and limited flood modeling complexity may facilitate local authorities and planners for deriving effective flood management strategies.

Child malnutrition and recurrent flooding in rural eastern India: a community-based survey

PubMed Central

Ranjan-Dash, Shisir; Degomme, Olivier; Mukhopadhyay, Alok; Guha-Sapir, Debarati

2011-01-01

Objectives This study aims to improve the understanding of the relationship between exposure to floods and malnutrition in children aged 6–59 months in rural India. Research has focused exclusively on Bangladeshi children, and few controlled epidemiological studies are available. Method A community-based cross-sectional study of child nutritional status was carried out in 14 flooded and 18 non-flooded villages of Jagatsinghpur district (Orissa) within one month of the September 2008 floods, and similarly affected by flooding in August 2006. Face-to-face interviews were conducted in 757 households in the flooded villages and 816 in the non-flooded communities. Data used in this study were from those households with children aged 6–59 months. In total, 191 and 161 children were measured, respectively. The association between various malnutrition indicators and the exposure to floods was assessed by univariate and multivariate logistic regression. Results Adjusted analyses revealed that children in flooded households were more likely stunted compared with those in non-flooded ones (adjusted prevalence ratio 1.60; 95% CI 1.05 to 2.44). The prevalence of underweight was also higher in children living in the flooded communities (adjusted prevalence ratio 1.86; 95% CI 1.04 to 3.30). Further analyses found that the 26–36-month flooded cohort, thus those children younger than 1 year during the precedent flood in August 2006, attained the largest difference in levels of stunting compared with the unexposed group of the same age. Conclusion Exposure to floods is associated with long-term malnutrition in these rural communities of Orissa, India. Children exposed to floods during their first year of life presented higher levels of chronic malnutrition. Long-term malnutrition prevention programmes after floods should be implemented in flood-prone areas. PMID:22080535

Flood-rich and flood-poor periods in Spain in 1942-2009

NASA Astrophysics Data System (ADS)

Mediero, Luis; Santillán, David; Garrote, Luis

2016-04-01

Several studies to detect trends in flood series at either national or trans-national scales have been conducted. Mediero et al. (2015) studied flood trends by using the longest streamflow records available in Europe. They found a decreasing trend in the Atlantic, Continental and Scandinavian regions. More specifically, Mediero et al. (2014) found a general decreasing trend in flood series in Spain in the period 1959-2009. Trends in flood series are usually detected by the Mann-Kendall test applied to a given period. However, the result of the Mann-Kendall test can change in terms of the starting and ending year of the series. Flood oscillations can occur and flood-rich and flood-poor periods could condition the results, especially when they are located at the beginning or end of the series. A methodology to identify statistically significant flood-rich and flood-poor periods is developed, based on the comparison between the expected sampling variability of floods when stationarity is assumed and the observed variability of floods in a given series. The methodology is applied to the longest series of annual maximum floods, peaks over threshold and counts of annual occurrences in peaks over threshold series observed in Spain in the period 1942-2009. A flood-rich period in 1950-1970 and a flood-poor period in 1970-1990 are identified in most of the selected sites. The generalised decreasing trend in flood series found by Mediero et al. (2014) could be explained by a flood-rich period placed at the beginning of the series and a flood-poor period located at the end of the series. References: Mediero, L., Kjeldsen, T.R., Macdonald, N., Kohnova, S., Merz, B., Vorogushyn, S., Wilson, D., Alburquerque, T., Blöschl, G., Bogdanowicz, E., Castellarin, A., Hall, J., Kobold, M., Kriauciuniene, J., Lang, M., Madsen, H., Onuşluel Gül, G., Perdigão, R.A.P., Roald, L.A., Salinas, J.L., Toumazis, A.D., Veijalainen, N., Óðinn Þórarinsson. Identification of coherent flood regions across Europe using the longest streamflow records, Journal of Hydrology, 528, 341-360, 2015. Mediero, L., Santillán, D., Garrote, L., Granados, A. Detection and attribution of trends in magnitude, frequency and timing of floods in Spain, Journal of Hydrology, 517, 1072-1088, 2014.

Remote-sensing-based rapid assessment of flood crop loss to support USDA flooding decision-making

NASA Astrophysics Data System (ADS)

Di, L.; Yu, G.; Yang, Z.; Hipple, J.; Shrestha, R.

2016-12-01

Floods often cause significant crop loss in the United States. Timely and objective assessment of flood-related crop loss is very important for crop monitoring and risk management in agricultural and disaster-related decision-making in USDA. Among all flood-related information, crop yield loss is particularly important. Decision on proper mitigation, relief, and monetary compensation relies on it. Currently USDA mostly relies on field surveys to obtain crop loss information and compensate farmers' loss claim. Such methods are expensive, labor intensive, and time consumptive, especially for a large flood that affects a large geographic area. Recent studies have demonstrated that Earth observation (EO) data are useful in post-flood crop loss assessment for a large geographic area objectively, timely, accurately, and cost effectively. There are three stages of flood damage assessment, including rapid assessment, early recovery assessment, and in-depth assessment. EO-based flood assessment methods currently rely on the time-series of vegetation index to assess the yield loss. Such methods are suitable for in-depth assessment but are less suitable for rapid assessment since the after-flood vegetation index time series is not available. This presentation presents a new EO-based method for the rapid assessment of crop yield loss immediately after a flood event to support the USDA flood decision making. The method is based on the historic records of flood severity, flood duration, flood date, crop type, EO-based both before- and immediate-after-flood crop conditions, and corresponding crop yield loss. It hypotheses that a flood of same severity occurring at the same pheonological stage of a crop will cause the similar damage to the crop yield regardless the flood years. With this hypothesis, a regression-based rapid assessment algorithm can be developed by learning from historic records of flood events and corresponding crop yield loss. In this study, historic records of MODIS-based flood and vegetation products and USDA/NASS crop type and crop yield data are used to train the regression-based rapid assessment algorithm. Validation of the rapid assessment algorithm indicates it can predict the yield loss at 90% accuracy, which is accurate enough to support USDA on flood-related quick response and mitigation.

Assessment of flood risk in Tokyo metropolitan area

NASA Astrophysics Data System (ADS)

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 This study is conducted as part of the research subject "Vulnerability and Adaptation to Climate Change in Water Hazard Assessed Using Regional Climate Scenarios in the Tokyo Region' (National Research Institute for Earth Science and Disaster Prevention; PI: Koji Dairaku) of Research Program on Climate Change Adaptation (RECCA) and was supported by the SOUSEI Program, funded by Ministry of Education, Culture, Sports, Science and Technology, Government of Japan

Real-time flood extent maps based on social media

NASA Astrophysics Data System (ADS)

Eilander, Dirk; van Loenen, Arnejan; Roskam, Ruud; Wagemaker, Jurjen

2015-04-01

During a flood event it is often difficult to get accurate information about the flood extent and the people affected. This information is very important for disaster risk reduction management and crisis relief organizations. In the post flood phase, information about the flood extent is needed for damage estimation and calibrating hydrodynamic models. Currently, flood extent maps are derived from a few sources such as satellite images, areal images and post-flooding flood marks. However, getting accurate real-time or maximum flood extent maps remains difficult. With the rise of social media, we now have a new source of information with large numbers of observations. In the city of Jakarta, Indonesia, the intensity of unique flood related tweets during a flood event, peaked at 8 tweets per second during floods in early 2014. A fair amount of these tweets also contains observations of water depth and location. Our hypothesis is that based on the large numbers of tweets it is possible to generate real-time flood extent maps. In this study we use tweets from the city of Jakarta, Indonesia, to generate these flood extent maps. The data-mining procedure looks for tweets with a mention of 'banjir', the Bahasa Indonesia word for flood. It then removes modified and retweeted messages in order to keep unique tweets only. Since tweets are not always sent directly from the location of observation, the geotag in the tweets is unreliable. We therefore extract location information using mentions of names of neighborhoods and points of interest. Finally, where encountered, a mention of a length measure is extracted as water depth. These tweets containing a location reference and a water level are considered to be flood observations. The strength of this method is that it can easily be extended to other regions and languages. Based on the intensity of tweets in Jakarta during a flood event we can provide a rough estimate of the flood extent. To provide more accurate flood extend information, we project the water depth observations in tweets on a digital elevation model using a flood-fill algorithm. Based on statistical methods we combine the large numbers of observations in order to create time series of flood extent maps. Early results indicate this method is very promising.

Floods in the Iowa River basin upstream from Coralville Lake, Iowa

USGS Publications Warehouse

Heinitz, Albert J.

1973-01-01

Flood profiles for the main stem include those for the 1947, 1954, 1969, the computed 25- and 50-year floods, and a partial profile for the June 1972 flood. On the West Branch Iowa River, profiles are shown for the 1944, 1969, the computed 25- and 50-year floods, and a partial profile for the June 1954 flood. On the East Branch Iowa River, profiles are shown for the 1954, 1969, the computed 25- and 50-year floods, and a partial profile for the June 1944 flood. Low-water profiles are shown for all reaches.

Understanding flood risk sensitivity and uncertainty in a subcatchment of the Thames River (United Kingdom)

NASA Astrophysics Data System (ADS)

Theofanidi, Sofia; Cloke, Hannah Louise; Clark, Joanna

2017-04-01

Floods are a global threat to social, economic and environmental development and there is a likelihood, that they could occur more frequently in the future due to climatic change. The severity of their impacts, which can last for years, has led to the urgent need for local communities and national authorities to develop flood warning systems for a better flood preparedness and emergency response. The flood warning systems often rely on hydrological forecasting tools to predict the hydrological response of a watershed before or during a flood event. Hydrological models have been substantially upgraded since the first use of hydrographs and the use of simple conceptual models. Hydrodynamic and hydraulic routing enables the spatial and temporal prediction of flow rates (peak discharges) and water levels. Moreover, the hydrodynamic modeling in 2D permits the estimation of the flood inundation area. This can be particularly useful because the flood zones can provide essential information about the flood risk and the flood damage. In this study, we use a hydrodynamic model which can simulate water levels and river flows in open channel conditions. The model can incorporate the effect of several river structures in the flood modeling process, such as the existence of bridges and weirs. The flood routing method is based on the solution of continuity and energy momentum equations. In addition, the floodplain inundation modeling which is based on the solution of shallow water equations along the channel's banks, will be used for the mapping of flood extent. A GIS interface will serve as a database, including high resolution topography, vector layers of river network, gauging stations, land use and land cover, geology and soil information. The flood frequency analysis, together with historical records on flood warnings, will enable the understanding on the flow regimes and the selection of particular flood events for modeling. One dimensional and two dimensional simulations of the flood events will follow, using simple hydrological boundary conditions. The sensitivity testing of the model, will permit to assess which parameters have the potential to alter significantly the peak discharge during the flood, flood water levels and flood inundation extent. Assessing the model's sensitivity and uncertainty, contributes to the improvement of the flood risk knowledge. The area of study is a subcatchment of the River Thames in the southern part of the United Kingdom. The Thames with its tributaries, support a wide range of social, economic and recreational activities. In addition, the historical and environmental importance of the Thames valley highlights the need for a sustainable flood mitigation planning which includes the better understanding of the flood mechanisms and flood risks.

The framing of two major flood episodes in the Irish print news media: Implications for societal adaptation to living with flood risk.

PubMed

Devitt, Catherine; O'Neill, Eoin

2017-10-01

Societal adaptation to flooding is a critical component of contemporary flood policy. Using content analysis, this article identifies how two major flooding episodes (2009 and 2014) are framed in the Irish broadsheet news media. The article considers the extent to which these frames reflect shifts in contemporary flood policy away from protection towards risk management, and the possible implications for adaptation to living with flood risk. Frames help us make sense of the social world, and within the media, framing is an essential tool for communication. Five frames were identified: flood resistance and structural defences, politicisation of flood risk, citizen as risk manager, citizen as victim and emerging trade-offs. These frames suggest that public debates on flood management do not fully reflect shifts in contemporary flood policy, with negative implications for the direction of societal adaptation. Greater discussion is required on the influence of the media on achieving policy objectives.

Spatial and Temporal Flood Risk Assessment for Decision Making Approach

NASA Astrophysics Data System (ADS)

Azizat, Nazirah; Omar, Wan-Mohd-Sabki Wan

2018-03-01

Heavy rainfall, adversely impacting inundation areas, depends on the magnitude of the flood. Significantly, location of settlements, infrastructure and facilities in floodplains result in many regions facing flooding risks. A problem faced by the decision maker in an assessment of flood vulnerability and evaluation of adaptation measures is recurrent flooding in the same areas. Identification of recurrent flooding areas and frequency of floods should be priorities for flood risk management. However, spatial and temporal variability become major factors of uncertainty in flood risk management. Therefore, dynamic and spatial characteristics of these changes in flood impact assessment are important in making decisions about the future of infrastructure development and community life. System dynamics (SD) simulation and hydrodynamic modelling are presented as tools for modelling the dynamic characteristics of flood risk and spatial variability. This paper discusses the integration between spatial and temporal information that is required by the decision maker for the identification of multi-criteria decision problems involving multiple stakeholders.

Study on the water flooding in the cathode of direct methanol fuel cells.

PubMed

Im, Hun Suk; Kim, Sang-Kyung; Lim, Seongyop; Peck, Dong-Hyun; Jung, Doohwan; Hong, Won Hi

2011-07-01

Water flooding phenomena in the cathode of direct methanol fuel cells were analyzed by using electrochemical impedance spectroscopy. Two kinds of commercial gas diffusion layers with different PTFE contents of 5 wt% (GDL A5) and 20 wt% (GDL B20) were used to investigate the water flooding under various operating conditions. Water flooding was divided into two types: catalyst flooding and backing flooding. The cathode impedance spectra of each gas diffusion layer was obtained and compared under the same conditions. The diameter of the capacitive semicircle became larger with increasing current density for both, and this increase was greater for GDL B20 than GDL A5. Catalyst flooding is dominant and backing flooding is negligible when the air flow rate is high and current density is low. An equivalent model was suggested and fitted to the experimental data. Parameters for catalyst flooding and backing flooding were individually obtained. The capacitance of the catalyst layer decreases as the air flow rate decreases when the catalyst flooding is dominant.

Use of documentary sources on past flood events for flood risk management and land planning

NASA Astrophysics Data System (ADS)

Cœur, Denis; Lang, Michel

2008-09-01

The knowledge of past catastrophic events can improve flood risk mitigation policy, with a better awareness against risk. As such historical information is usually available in Europe for the past five centuries, historians are able to understand how past society dealt with flood risk, and hydrologists can include information on past floods into an adapted probabilistic framework. In France, Flood Risk Mitigation Maps are based either on the largest historical known flood event or on the 100-year flood event if it is greater. Two actions can be suggested in terms of promoting the use of historical information for flood risk management: (1) the development of a regional flood data base, with both historical and current data, in order to get a good feedback on recent events and to improve the flood risk education and awareness; (2) the commitment to keep a persistent/perennial management of a reference network of hydrometeorological observations for climate change studies.

Flood resilience and uncertainty in flood risk assessment

NASA Astrophysics Data System (ADS)

Beven, K.; Leedal, D.; Neal, J.; Bates, P.; Hunter, N.; Lamb, R.; Keef, C.

2012-04-01

Flood risk assessments do not normally take account of the uncertainty in assessing flood risk. There is no requirement in the EU Floods Directive to do so. But given the generally short series (and potential non-stationarity) of flood discharges, the extrapolation to smaller exceedance potentials may be highly uncertain. This means that flood risk mapping may also be highly uncertainty, with additional uncertainties introduced by the representation of flood plain and channel geometry, conveyance and infrastructure. This suggests that decisions about flood plain management should be based on exceedance probability of risk rather than the deterministic hazard maps that are common in most EU countries. Some examples are given from 2 case studies in the UK where a framework for good practice in assessing uncertainty in flood risk mapping has been produced as part of the Flood Risk Management Research Consortium and Catchment Change Network Projects. This framework provides a structure for the communication and audit of assumptions about uncertainties.

Influence of solid waste and topography on urban floods: The case of Mexico City.

PubMed

Zambrano, Luis; Pacheco-Muñoz, Rodrigo; Fernández, Tania

2018-02-24

Floods in cities are increasingly common as a consequence of multifactor watershed dynamics, including geomorphology, land-use changes and land subsidence. However, urban managers have focused on infrastructure to address floods by reducing blocked sewage infrastructure, without significant success. Using Mexico City as a case study, we generated a spatial flood risk model with geomorphology and anthropogenic variables. The results helped contrast the implications of different public policies in land use and waste disposal, and correlating them with flood hazards. Waste disposal was only related to small floods. 58% of the city has a high risk of experiencing small floods, and 24% of the city has a risk for large floods. Half of the population with the lowest income is located in the high-risk areas for large floods. These models are easy to build, generate fast results and are able to help to flood policies, by understanding flood interactions in urban areas within the watershed.

Rapid flood loss estimation for large scale floods in Germany

NASA Astrophysics Data System (ADS)

Schröter, Kai; Kreibich, Heidi; Merz, Bruno

2013-04-01

Rapid evaluations of flood events are needed for efficient responses both in emergency management and financial appraisal. Beyond that, closely monitoring and documenting the formation and development of flood events and their impacts allows for an improved understanding and in depth analyses of the interplay between meteorological, hydrological, hydraulic and societal causes leading to flood damage. This contribution focuses on the development of a methodology for the rapid assessment of flood events. In the first place, the focus is on the prediction of damage to residential buildings caused by large scale floods in Germany. For this purpose an operational flood event analysis system is developed. This system has basic spatial thematic data available and supports data capturing about the current flood situation. This includes the retrieval of online gauge data and the integration of remote sensing data. Further, it provides functionalities to evaluate the current flood situation, to assess the hazard extent and intensity and to estimate the current flood impact using the flood loss estimation model FLEMOps+r. The operation of the flood event analysis system will be demonstrated for the past flood event from January 2011 with a focus on the Elbe/Saale region. On this grounds, further requirements and potential for improving the information basis as for instance by including hydrological and /or hydraulic model results as well as information from social sensors will be discussed.

Nutrient Budgets Calculated in Floodwaters Using a Whole-Ecosystem Experimental Manipulation

NASA Astrophysics Data System (ADS)

Talbot, C. J.; Paterson, M. J.; Xenopoulos, M. A.

2017-12-01

Flooding provides pathways for nutrients to move into surface waters and alter nutrient concentrations, therefore influencing downstream ecosystems and increasing events of eutrophication. Nutrient enrichment will likely affect water quality, primary production, and overall ecosystem function. Quantifying nutrient movement post-flood will help evaluate the risks or advantages that flooding will have on ecosystem processes. Here we constructed nutrient budgets using data collected as part of the Flooded Upland Dynamics Experiment (FLUDEX) at the Experimental Lakes Area (ELA) in northwestern Ontario. Three experimental reservoirs with varying amounts of stored carbon were created by flooding forested land from May through September annually from 1999 to 2003. Organic matter became a significant source of nutrients under flooded conditions and elevated reservoir total nitrogen (TN) and total phosphorus (TP) concentrations within one week of flooding. The highest TN (2.6 mg L-1) and TP (579 µg L-1) concentrations throughout the entire flooding experiment occurred in the medium carbon reservoir within the first two weeks of flooding in 1999. TN and TP fluxes were positive in all years of flooding. TP fluxes decreased after each flooding season therefore, TP production may be less problematic in floodplains subject to frequent repeated flooding. However, TN fluxes remained large even after repeated flooding. Therefore, flooding, whether naturally occurring or from anthropogenic flow alteration, may be responsible for producing significant amounts of nitrogen and phosphorus in aquatic ecosystems.

Simulation of Flood Profiles for Fivemile Creek at Tarrant, Alabama, 2006

USGS Publications Warehouse

Lee, K.G.; Hedgecock, T.S.

2007-01-01

A one-dimensional step-backwater model was used to simulate flooding conditions for Fivemile Creek at Tarrant, Alabama. The 100-year flood stage published in the current flood insurance study for Tarrant by the Federal Emergency Management Agency was significantly exceeded by the March 2000 and May 2003 floods in this area. A peak flow of 14,100 cubic feet per second was computed by the U.S. Geological Survey for the May 2003 flood in the vicinity of Lawson Road. Using this estimated peak flow, flood-plain surveys with associated roughness coefficients, and the surveyed high-water profile for the May 2003 flood, a flow model was calibrated to closely match this known event. The calibrated model was then used to simulate flooding for the 10-, 50-, 100-, and 500-year recurrence interval floods. The results indicate that for the 100-year recurrence interval, the flood profile is about 2.5 feet higher, on average, than the profile published by the Federal Emergency Management Agency. The absolute maximum and minimum difference is 6.80 feet and 0.67 foot, respectively. All water-surface elevations computed for the 100-year flood are higher than those published by the Federal Emergency Management Agency, except for cross section H. The results of this study provide the community with flood-profile information that can be used for existing flood-plain mitigation, future development, and safety plans for the city.

Comparing flood loss models of different complexity

NASA Astrophysics Data System (ADS)

Schröter, Kai; Kreibich, Heidi; Vogel, Kristin; Riggelsen, Carsten; Scherbaum, Frank; Merz, Bruno

2013-04-01

Any deliberation on flood risk requires the consideration of potential flood losses. In particular, reliable flood loss models are needed to evaluate cost-effectiveness of mitigation measures, to assess vulnerability, for comparative risk analysis and financial appraisal during and after floods. In recent years, considerable improvements have been made both concerning the data basis and the methodological approaches used for the development of flood loss models. Despite of that, flood loss models remain an important source of uncertainty. Likewise the temporal and spatial transferability of flood loss models is still limited. This contribution investigates the predictive capability of different flood loss models in a split sample cross regional validation approach. For this purpose, flood loss models of different complexity, i.e. based on different numbers of explaining variables, are learned from a set of damage records that was obtained from a survey after the Elbe flood in 2002. The validation of model predictions is carried out for different flood events in the Elbe and Danube river basins in 2002, 2005 and 2006 for which damage records are available from surveys after the flood events. The models investigated are a stage-damage model, the rule based model FLEMOps+r as well as novel model approaches which are derived using data mining techniques of regression trees and Bayesian networks. The Bayesian network approach to flood loss modelling provides attractive additional information concerning the probability distribution of both model predictions and explaining variables.

Assessment of big floods in the Eastern Black Sea Basin of Turkey.

PubMed

Yüksek, Ömer; Kankal, Murat; Üçüncü, Osman

2013-01-01

In this study, general knowledge and some details of the floods in Eastern Black Sea Basin of Turkey are presented. Brief hydro-meteorological analysis of selected nine floods and detailed analysis of the greatest flood are given. In the studied area, 51 big floods have taken place between 1955-2005 years, causing 258 deaths and nearly US $500,000,000 of damage. Most of the floods have occurred in June, July and August. It is concluded that especially for the rainstorms that have caused significantly damages, the return periods of the rainfall heights and resultant flood discharges have gone up to 250 and 500 years, respectively. A general agreement is observed between the return periods of rains and resultant floods. It is concluded that there has been no significant climate change to cause increases in flood harms. The most important human factors to increase the damage are determined as wrong and illegal land use, deforestation and wrong urbanization and settlement, psychological and technical factors. Some structural and non-structural measures to mitigate flood damages are also included in the paper. Structural measures include dykes and flood levees. Main non-structural measures include flood warning system, modification of land use, watershed management and improvement, flood insurance, organization of flood management studies, coordination between related institutions and education of the people and informing of the stakeholders.

Prevention, adaptation, and threat denial: flooding experiences in the Netherlands.

PubMed

Zaalberg, Ruud; Midden, Cees; Meijnders, Anneloes; McCalley, Teddy

2009-12-01

Delta areas such as the Netherlands are more and more at risk of future flooding due to global climate change. Motivating residents living in flood-prone areas to effectively cope with local floods may lead to minimization of material losses and loss of life. The aim of this research was to investigate whether the extent to which residents had been exposed to flooding in the past was a key factor in motivating residents to effectively cope with future flooding. We also focused on the psychological variables that mediated this relationship. We conducted a survey (N = 516) among flood victims and nonvictims. We assessed subjective experiences due to past flooding, affective and cognitive appraisals, and coping responses. Results show that victims reported stronger emotions (negative and positive), and the receipt of more social support due to past flooding than did nonvictims. Moreover, victims worry more about future flooding, perceive themselves as more vulnerable to future flooding, perceive the consequences of future flooding as more severe, and have stronger intentions to take adaptive actions in the future than nonvictims. Structural equation modeling reveals that the latter effect was fully mediated by specific experiences and appraisals. Insights into factors and processes that have the potential to motivate residents to effectively cope with future floods may prove helpful in developing interventions to inform residents how to act effectively in case of an imminent flood.

Impacts of adaptive flood management strategies on the Socio-Hydrological system in Ganges - Brahmaputra river basin, Bangladesh

NASA Astrophysics Data System (ADS)

Sung, K.; Jeong, H.; Sangwan, N.; Yu, D. J.

2017-12-01

Human societies have tried to prevent floods by building robust infrastructure such as levees or dams. However, some scholars raise a doubt to this approach because of a lack of adaptiveness to environmental and societal changes in a long-term. Thus, a growing number of studies now suggest adopting new strategies in flood management to reinforce an adapt capacity to the long-term flood risk. This study addresses this issue by developing a conceptual mathematical model exploring how flood management strategies effect to the dynamics human-flood interaction, ultimately the flood resilience in a long-term. Especially, our model is motivated by the community-based flood protection system in southwest coastal area in Bangladesh. We developed several conceptual flood management strategies and investigated the interplay between those strategies and community's capacity to cope with floods. We additionally analyzed how external disturbances (sea level rise, water tide level change, and outside economic development) alter the adaptive capacity to flood risks. The results of this study reveal that the conventional flood management has potential vulnerabilities as external disturbances increase. Our results also highlight the needs of the adaptive strategy as a new paradigm in flood management which is able to feedback to the social and hydrological conditions. These findings provide insights on the resilience-based, adaptive strategies which can build flood resilience under global change.

Development of Integrated Flood Analysis System for Improving Flood Mitigation Capabilities in Korea

NASA Astrophysics Data System (ADS)

Moon, Young-Il; Kim, Jong-suk

2016-04-01

Recently, the needs of people are growing for a more safety life and secure homeland from unexpected natural disasters. Flood damages have been recorded every year and those damages are greater than the annual average of 2 trillion won since 2000 in Korea. It has been increased in casualties and property damages due to flooding caused by hydrometeorlogical extremes according to climate change. Although the importance of flooding situation is emerging rapidly, studies related to development of integrated management system for reducing floods are insufficient in Korea. In addition, it is difficult to effectively reduce floods without developing integrated operation system taking into account of sewage pipe network configuration with the river level. Since the floods result in increasing damages to infrastructure, as well as life and property, structural and non-structural measures should be urgently established in order to effectively reduce the flood. Therefore, in this study, we developed an integrated flood analysis system that systematized technology to quantify flood risk and flood forecasting for supporting synthetic decision-making through real-time monitoring and prediction on flash rain or short-term rainfall by using radar and satellite information in Korea. Keywords: Flooding, Integrated flood analysis system, Rainfall forecasting, Korea Acknowledgments This work was carried out with the support of "Cooperative Research Program for Agriculture Science & Technology Development (Project No. PJ011686022015)" Rural Development Administration, Republic of Korea

33 CFR 203.50 - Nonstructural alternatives to rehabilitation of flood control works.

Code of Federal Regulations, 2014 CFR

2014-07-01

... DISASTER PROCEDURES Rehabilitation Assistance for Flood Control Works Damaged by Flood or Coastal Storm... rehabilitation, repair, or restoration of flood control works damaged by floods or coastal storms. (b) Policy. (1...

Flood control surveys in the northeast

Treesearch

Arthur Bevan

1947-01-01

Floods are a grave danger to our Nation's resources. It is estimated that floods cost the United States at least $100 million every year. The recent Mississippi floods, which dramatically brought the seriousness of the situation to public attention, cost half a billion dollars in direct-damages. The Northeast carries a heavy burden of flood losses. In 1936, floods...

12 CFR 339.7 - Forced placement of flood insurance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 4 2010-01-01 2010-01-01 false Forced placement of flood insurance. 339.7... GENERAL POLICY LOANS IN AREAS HAVING SPECIAL FLOOD HAZARDS § 339.7 Forced placement of flood insurance. If... not covered by flood insurance or is covered by flood insurance in an amount less than the amount...

12 CFR 572.7 - Forced placement of flood insurance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Forced placement of flood insurance. 572.7... HAVING SPECIAL FLOOD HAZARDS § 572.7 Forced placement of flood insurance. If a savings association, or a... not covered by flood insurance or is covered by flood insurance in an amount less than the amount...

25 CFR 256.24 - Will I need flood insurance?

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Will I need flood insurance? 256.24 Section 256.24... Will I need flood insurance? You will need flood insurance if your dwelling is located in an area identified as having special flood hazards under the Flood Disaster Protection Act of 1973 (Pub. L. 93-234...

12 CFR 760.7 - Forced placement of flood insurance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Forced placement of flood insurance. 760.7... LOANS IN AREAS HAVING SPECIAL FLOOD HAZARDS § 760.7 Forced placement of flood insurance. If a credit... not covered by flood insurance, or is covered by flood insurance in an amount less than the amount...

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

Code of Federal Regulations, 2010 CFR

2010-10-01

... from flooding.” (6) Data to substantiate the base flood elevation. If we complete a Flood Insurance Study (FIS), we will use those data to substantiate the base flood elevation. Otherwise, the community... technical data prepared and certified by a registered professional engineer. If base flood elevations have...

Learning about Flood Risk: Comparing the Web-Based and Physical Flood-Walk Learning Environments

ERIC Educational Resources Information Center

Chang Rundgren, Shu-Nu; Nyberg, Lars; Evers, Mariele; Alexandersson, Jan

2015-01-01

Numerous of sustainable development related challenges are emerging today, e.g. flooding problems. Our group has developed "the flood walk" project since 2010 to convey flood risk knowledge in an authentic context. Considering the limitation of time and space to educate people the flood risk knowledge, we tried to transform the physical…

High-resolution urban flood modelling - a joint probability approach

NASA Astrophysics Data System (ADS)

Hartnett, Michael; Olbert, Agnieszka; Nash, Stephen

2017-04-01

The hydrodynamic modelling of rapid flood events due to extreme climatic events in urban environment is both a complex and challenging task. The horizontal resolution necessary to resolve complexity of urban flood dynamics is a critical issue; the presence of obstacles of varying shapes and length scales, gaps between buildings and the complex geometry of the city such as slopes affect flow paths and flood levels magnitudes. These small scale processes require a high resolution grid to be modelled accurately (2m or less, Olbert et al., 2015; Hunter et al., 2008; Brown et al., 2007) and, therefore, altimetry data of at least the same resolution. Along with availability of high-resolution LiDAR data and computational capabilities, as well as state of the art nested modelling approaches, these problems can now be overcome. Flooding and drying, domain definition, frictional resistance and boundary descriptions are all important issues to be addressed when modelling urban flooding. In recent years, the number of urban flood models dramatically increased giving a good insight into various modelling problems and solutions (Mark et al., 2004; Mason et al., 2007; Fewtrell et al., 2008; Shubert et al., 2008). Despite extensive modelling work conducted for fluvial (e.g. Mignot et al., 2006; Hunter et al., 2008; Yu and Lane, 2006) and coastal mechanisms of flooding (e.g. Gallien et al., 2011; Yang et al., 2012), the amount of investigations into combined coastal-fluvial flooding is still very limited (e.g. Orton et al., 2012; Lian et al., 2013). This is surprising giving the extent of flood consequences when both mechanisms occur simultaneously, which usually happens when they are driven by one process such as a storm. The reason for that could be the fact that the likelihood of joint event is much smaller than those of any of the two contributors occurring individually, because for fast moving storms the rainfall-driven fluvial flood arrives usually later than the storm surge (Divoky et al., 2005). Nevertheless, such events occur and in Ireland alone there are several cases of serious damage due to flooding resulting from a combination of high sea water levels and river flows driven by the same meteorological conditions (e.g. Olbert et al. 2015). A November 2009 fluvial-coastal flooding of Cork City bringing €100m loss was one such incident. This event was used by Olbert et al. (2015) to determine processes controlling urban flooding and is further explored in this study to elaborate on coastal and fluvial flood mechanisms and their roles in controlling water levels. The objective of this research is to develop a methodology to assess combined effect of multiple source flooding on flood probability and severity in urban areas and to establish a set of conditions that dictate urban flooding due to extreme climatic events. These conditions broadly combine physical flood drivers (such as coastal and fluvial processes), their mechanisms and thresholds defining flood severity. The two main physical processes controlling urban flooding: high sea water levels (coastal flooding) and high river flows (fluvial flooding), and their threshold values for which flood is likely to occur, are considered in this study. Contribution of coastal and fluvial drivers to flooding and their impacts are assessed in a two-step process. The first step involves frequency analysis and extreme value statistical modelling of storm surges, tides and river flows and ultimately the application of joint probability method to estimate joint exceedence return periods for combination of surges, tide and river flows. In the second step, a numerical model of Cork Harbour MSN_Flood comprising a cascade of four nested high-resolution models is used to perform simulation of flood inundation under numerous hypothetical coastal and fluvial flood scenarios. The risk of flooding is quantified based on a range of physical aspects such as the extent and depth of inundation (Apel et al., 2008) The methodology includes estimates of flood probabilities due to coastal- and fluvial-driven processes occurring individually or jointly, mechanisms of flooding and their impacts on urban environment. Various flood scenarios are examined in order to demonstrate that this methodology is necessary to quantify the important physical processes in coastal flood predictions. Cork City, located on the south of Ireland subject to frequent coastal-fluvial flooding, is used as a study case.

Framework for probabilistic flood risk assessment in an Alpine region

NASA Astrophysics Data System (ADS)

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 historic and synthetic flood events have to be spatially interpolated from point scale (i.e. river gauges) to the river network. Therefore, topological kriging (Top-kriging) proposed by Skøien et al. (2006) is applied. Top-kriging considers the nested structure of river networks and is therefore suitable to regionalise flood characteristics. Thus, the characteristics of a large number of possible flood events can be transferred to arbitrary locations (e.g. community level) at the river network within a study region. This framework has been used to generate a set of spatial correlated river flood events in the Austrian Federal Province of Vorarlberg. In addition, loss-probability-curves for each community has been calculated based on official inundation maps of public authorities, elements at risks and their vulnerability. One location along the river network within each community refers as interface between the set of flood events and the individual loss-probability relationships for the individual communities. Consequently, every flood event from the historic and synthetic generated dataset can be monetary evaluated. Thus, a time series comprising a large number of flood events and their corresponding monetary losses serves as basis for a probabilistic flood risk assessment. This includes expected annual losses and estimates of extreme event losses, which occur over the course of a certain time period. The gained results are essential decision-support for primary insurers, reinsurance companies and public authorities in order to setup a scale adequate risk management.

A National Assessment of Changes in Flood Exposure in the United States

NASA Astrophysics Data System (ADS)

Lam, N.; Qiang, Y.; Cai, H.; Zou, L.

2017-12-01

Analyzing flood exposure and its temporal trend is the first step toward understanding flood risk, flood hazard, and flood vulnerability. This presentation is based on a national, county-based study assessing the changes in population and urban areas in high-risk flood zones from 2001-2011 in the contiguous United States. Satellite land use land cover data, Federal Emergency Management Agency (FEMA)'s 100-year flood maps, and census data were used to extract the proportion of developed (urban) land in flood zones by county in the two time points, and indices of difference were calculated. Local Moran's I statistic was applied to identify hotspots of increase in urban area in flood zones, and geographically weighted regression was used to estimate the population in flood zones from the land cover data. Results show that in 2011, an estimate of about 25.3 million people (8.3% of the total population) lived in the high-risk flood zones. Nationally, the ratio of urban development in flood zones is less than the ratio of land in flood zones, implying that Americans were responsive to flood hazards by avoiding development in flood zones. However, this trend varied from place to place, with coastal counties having less urban development in flood zones than the inland counties. Furthermore, the contrast between coastal and inland counties increased during 2001-2011. Finally, several exceptions from the trend (hotspots) were detected, most notably New York City and Miami where significant increases in urban development in flood zones were found. This assessment provides important baseline information on the spatial patterns of flood exposure and their changes from 2001-2011. The study pinpoints regions that may need further investigations and better policy to reduce the overall flood risks. Methodologically, the study demonstrates that pixelated land cover data can be integrated with other natural and human data to investigate important societal problems. The same methodology can be easily extended worldwide to assess the overall trend as well as identify hotspots that need further attention.

Assessing the impact of climate change on flood types in the Austrian and French Alps using the stochastic weather generator TripleM and rainfall-runoff modeling

NASA Astrophysics Data System (ADS)

Breinl, Korbinian; Turkington, Thea

2017-04-01

We developed a new methodology for classifying flood types, which appears to be particularly suitable for climate change impact studies. Climate change is not only expected to change the magnitude and frequency of Alpine floods but also the types of floods. The distribution of existing flood types may change and new flood types may develop. A shift away from solely focusing on the magnitude and frequency of floods in flood hazard assessment and disaster risk management towards the causal types of floods is required as the types and therefore also timing and characteristics of floods will have implications on both the local social and ecological systems. The flood types are classified using k-means clustering of temperature and precipitation indicators, capturing differences in rainfall amounts, antecedent rainfall, snow-cover, and the day of the year. In a first step, we used the open-source multi-site weather generator TripleM coupled with the fast conceptual rainfall-runoff model HBV to extrapolate the observed discharge time series and generate a large inventory of different types of observed flood events and flood types. The weather generator was then parameterized based on projections of rainfall and temperature to simulate future flood types and events. We selected four climate projections (mild dry, mild wet, warm dry and warm wet conditions) from a set of 15, which originated from the EURO-CORDEX dataset. We worked in two catchments in the Austrian and French Alps that have been affected by floods in the past: the medium-sized Salzach catchment in Austria, which is dominated by rainfall driven flooding during the summer and autumn period, and the small Ubaye catchment in the Southern French Alps, which is dominated by rain-on-snow floods in the spring period. The analysis of the simulated future flood types shows clear changes in the distribution and characteristics of flood types in both study areas under the different climate projections examined.

Challenges in estimating the health impact of Hurricane Sandy using macro-level flood data.

NASA Astrophysics Data System (ADS)

Lieberman-Cribbin, W.; Liu, B.; Schneider, S.; Schwartz, R.; Taioli, E.

2016-12-01

Background: Hurricane Sandy caused extensive physical and economic damage but the long-term health impacts are unknown. Flooding is a central component of hurricane exposure, influencing health through multiple pathways that unfold over months after flooding recedes. This study assesses concordance in Federal Emergency Management (FEMA) and self-reported flood exposure after Hurricane Sandy to elucidate discrepancies in flood exposure assessments. Methods: Three meter resolution New York State flood data was obtained from the FEMA Modeling Task Force Hurricane Sandy Impact Analysis. FEMA data was compared to self-reported flood data obtained through validated questionnaires from New York City and Long Island residents following Sandy. Flooding was defined as both dichotomous and continuous variables and analyses were performed in SAS v9.4 and ArcGIS 10.3.1. Results: There was a moderate agreement between FEMA and self-reported flooding (Kappa statistic 0.46) and continuous (Spearman's correlation coefficient 0.50) measures of flood exposure. Flooding was self-reported and recorded by FEMA in 23.6% of cases, while agreement between the two measures on no flooding was 51.1%. Flooding was self-reported but not recorded by FEMA in 8.5% of cases, while flooding was not self-reported but indicated by FEMA in 16.8% of cases. In this last instance, 84% of people (173/207; 83.6%) resided in an apartment (no flooding reported). Spatially, the most concordance resided in the interior of New York City / Long Island, while the greatest areas of discordance were concentrated in the Rockaway Peninsula and Long Beach, especially among those living in apartments. Conclusions: There were significant discrepancies between FEMA and self-reported flood data. While macro-level FEMA flood data is a relatively less expensive and faster way to provide exposure estimates spanning larger geographic areas affected by Hurricane Sandy than micro-level estimates from cohort studies, macro-level exposure estimates may underestimate the full flooding and health impacts of the hurricane. Future disaster preparedness efforts must integrate micro and macro-level flood exposures to produce the most accurate evaluation of health impacts in affected populations.

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

NASA Astrophysics Data System (ADS)

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/

Mapping Daily and Maximum Flood Extents at 90-m Resolution During Hurricanes Harvey and Irma Using Passive Microwave Remote Sensing

NASA Astrophysics Data System (ADS)

Galantowicz, J. F.; Picton, J.; Root, B.

2017-12-01

Passive microwave remote sensing can provided a distinct perspective on flood events by virtue of wide sensor fields of view, frequent observations from multiple satellites, and sensitivity through clouds and vegetation. During Hurricanes Harvey and Irma, we used AMSR2 (Advanced Microwave Scanning Radiometer 2, JAXA) data to map flood extents starting from the first post-storm rain-free sensor passes. Our standard flood mapping algorithm (FloodScan) derives flooded fraction from 22-km microwave data (AMSR2 or NASA's GMI) in near real time and downscales it to 90-m resolution using a database built from topography, hydrology, and Global Surface Water Explorer data and normalized to microwave data footprint shapes. During Harvey and Irma we tested experimental versions of the algorithm designed to map the maximum post-storm flood extent rapidly and made a variety of map products available immediately for use in storm monitoring and response. The maps have several unique features including spanning the entire storm-affected area and providing multiple post-storm updates as flood water shifted and receded. From the daily maps we derived secondary products such as flood duration, maximum flood extent (Figure 1), and flood depth. In this presentation, we describe flood extent evolution, maximum extent, and local details as detected by the FloodScan algorithm in the wake of Harvey and Irma. We compare FloodScan results to other available flood mapping resources, note observed shortcomings, and describe improvements made in response. We also discuss how best-estimate maps could be updated in near real time by merging FloodScan products and data from other remote sensing systems and hydrological models.

Mapping technological and biophysical capacities of watersheds to regulate floods

USGS Publications Warehouse

Mogollón, Beatriz; Villamagna, Amy M.; Frimpong, Emmanuel A.; Angermeier, Paul

2016-01-01

Flood regulation is a widely valued and studied service provided by watersheds. Flood regulation benefits people directly by decreasing the socio-economic costs of flooding and indirectly by its positive impacts on cultural (e.g., fishing) and provisioning (e.g., water supply) ecosystem services. Like other regulating ecosystem services (e.g., pollination, water purification), flood regulation is often enhanced or replaced by technology, but the relative efficacy of natural versus technological features in controlling floods has scarcely been examined. In an effort to assess flood regulation capacity for selected urban watersheds in the southeastern United States, we: (1) used long-term flood records to assess relative influence of technological and biophysical indicators on flood magnitude and duration, (2) compared the widely used runoff curve number (RCN) approach for assessing the biophysical capacity to regulate floods to an alternative approach that acknowledges land cover and soil properties separately, and (3) mapped technological and biophysical flood regulation capacities based on indicator importance-values derived for flood magnitude and duration. We found that watersheds with high biophysical (via the alternative approach) and technological capacities lengthened the duration and lowered the peak of floods. We found the RCN approach yielded results opposite that expected, possibly because it confounds soil and land cover processes, particularly in urban landscapes, while our alternative approach coherently separates these processes. Mapping biophysical (via the alternative approach) and technological capacities revealed great differences among watersheds. Our study improves on previous mapping of flood regulation by (1) incorporating technological capacity, (2) providing high spatial resolution (i.e., 10-m pixel) maps of watershed capacities, and (3) deriving importance-values for selected landscape indicators. By accounting for technology that enhances or replaces natural flood regulation, our approach enables watershed managers to make more informed choices in their flood-control investments.

Flood risk analysis for flood control and sediment transportation in sandy regions: A case study in the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Guo, Aijun; Chang, Jianxia; Wang, Yimin; Huang, Qiang; Zhou, Shuai

2018-05-01

Traditional flood risk analysis focuses on the probability of flood events exceeding the design flood of downstream hydraulic structures while neglecting the influence of sedimentation in river channels on regional flood control systems. This work advances traditional flood risk analysis by proposing a univariate and copula-based bivariate hydrological risk framework which incorporates both flood control and sediment transport. In developing the framework, the conditional probabilities of different flood events under various extreme precipitation scenarios are estimated by exploiting the copula-based model. Moreover, a Monte Carlo-based algorithm is designed to quantify the sampling uncertainty associated with univariate and bivariate hydrological risk analyses. Two catchments located on the Loess plateau are selected as study regions: the upper catchments of the Xianyang and Huaxian stations (denoted as UCX and UCH, respectively). The univariate and bivariate return periods, risk and reliability in the context of uncertainty for the purposes of flood control and sediment transport are assessed for the study regions. The results indicate that sedimentation triggers higher risks of damaging the safety of local flood control systems compared with the event that AMF exceeds the design flood of downstream hydraulic structures in the UCX and UCH. Moreover, there is considerable sampling uncertainty affecting the univariate and bivariate hydrologic risk evaluation, which greatly challenges measures of future flood mitigation. In addition, results also confirm that the developed framework can estimate conditional probabilities associated with different flood events under various extreme precipitation scenarios aiming for flood control and sediment transport. The proposed hydrological risk framework offers a promising technical reference for flood risk analysis in sandy regions worldwide.

Re-assessing the flood risk in Scotland.

PubMed

Black, Andrew R; Burns, John C

2002-07-22

This paper presents a review of changes in flood risk estimation on Scottish rivers resulting from re-analysis of flood records or from the application of new methods. The review arises at a time when flood damages have received recent prominence through the occurrence of a number of extreme floods in Scotland, and when the possible impacts of climate change on flood risk are receiving considerable attention. An analysis of the nine longest available peaks-over-threshold (POT) flood series for Scottish rivers reveals that, for thresholds yielding two events per year on average, annual POT frequencies on western rivers have increased in the 1980s/1990s to maximum recorded values, while in the east, values were highest in the 1950s/1960s. These results support the results of flood modelling work based on rainfall and temperature records from the 1870s, which indicate that, in western catchments, annual POT frequencies in the 1980s/1990s are unprecedented. No general trends in flood magnitude series were found, but an unexpected cluster of extreme floods is identified as having occurred since 1988, resulting in eight of Scotland's 16 largest gauged rivers producing their maximum recorded flows since then. These shifts are related to recent increases in the dominance of westerly airflows, share similarities with the results of climate change modelling, and collectively point to increases in flood risk in many parts of Scotland. The paper also reviews advances in flood risk estimation arising from the publication of the UK Flood Estimation Handbook, developments in the collection and use of historic flood estimation and the production of maps of 100-year flood areal extent. Finally the challenges in flood risk estimation posed by climate change are examined, particularly in relation to the assumption of stationarity.

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

NASA Astrophysics Data System (ADS)

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.

The complexities of urban flood response: Flood frequency analyses for the Charlotte metropolitan region

NASA Astrophysics Data System (ADS)

Zhou, Zhengzheng; Smith, James A.; Yang, Long; Baeck, Mary Lynn; Chaney, Molly; Ten Veldhuis, Marie-Claire; Deng, Huiping; Liu, Shuguang

2017-08-01

We examine urban flood response through data-driven analyses for a diverse sample of "small" watersheds (basin scale ranging from 7.0 to 111.1 km2) in the Charlotte Metropolitan region. These watersheds have experienced extensive urbanization and suburban development since the 1960s. The objective of this study is to develop a broad characterization of land surface and hydrometeorological controls of urban flood hydrology. Our analyses are based on peaks-over-threshold flood data developed from USGS streamflow observations and are motivated by problems of flood hazard characterization for urban regions. We examine flood-producing rainfall using high-resolution (1 km2 spatial resolution and 15 min time resolution), bias-corrected radar rainfall fields that are developed through the Hydro-NEXRAD system. The analyses focus on the 2001-2015 period. The results highlight the complexities of urban flood response. There are striking spatial heterogeneities in flood peak magnitudes, response times, and runoff ratios across the study region. These spatial heterogeneities are mainly linked to watershed scale, the distribution of impervious cover, and storm water management. Contrasting land surface properties also determine the mixture of flood-generating mechanisms for a particular watershed. Warm-season thunderstorm systems and tropical cyclones are main flood agents in Charlotte, with winter/spring storms playing a role in less-urbanized watersheds. The mixture of flood agents exerts a strong impact on the upper tail of flood frequency distributions. Antecedent watershed wetness plays a minor role in urban flood response, compared with less-urbanized watersheds. Implications for flood hazard characterization in urban watersheds and for advances in flood science are discussed.

Evaluation of levee setbacks for flood-loss reduction, Middle Mississippi River, USA

NASA Astrophysics Data System (ADS)

Dierauer, Jennifer; Pinter, Nicholas; Remo, Jonathan W. F.

2012-07-01

SummaryOne-dimensional hydraulic modeling and flood-loss modeling were used to test the effectiveness of levee setbacks for flood-loss reduction along the Middle Mississippi River (MMR). Four levee scenarios were assessed: (1) the present-day levee configuration, (2) a 1000 m levee setback, (3) a 1500 m levee setback, and (4) an optimized setback configuration. Flood losses were estimated using FEMA's Hazus-MH (Hazards US Multi-Hazard) loss-estimation software on a structure-by-structure basis for a range of floods from the 2- to the 500-year events. These flood-loss estimates were combined with a levee-reliability model to calculate probability-weighted damage estimates. In the simplest case, the levee setback scenarios tested here reduced flood losses compared to current conditions for large, infrequent flooding events but increased flood losses for smaller, more frequent flood events. These increases occurred because levee protection was removed for some of the existing structures. When combined with buyouts of unprotected structures, levee setbacks reduced flood losses for all recurrence intervals. The "optimized" levee setback scenario, involving a levee configuration manually planned to protect existing high-value infrastructure, reduced damages with or without buyouts. This research shows that levee setbacks in combination with buyouts are an economically viable approach for flood-risk reduction along the study reach and likely elsewhere where levees are widely employed for flood control. Designing a levee setback around existing high-value infrastructure can maximize the benefit of the setback while simultaneously minimizing the costs. The optimized levee setback scenario analyzed here produced payback periods (costs divided by benefits) of less than 12 years. With many aging levees failing current inspections across the US, and flood losses spiraling up over time, levee setbacks are a viable solution for reducing flood exposure and flood levels.

Assessment of Vulnerability to Extreme Flash Floods in Design Storms

PubMed Central

Kim, Eung Seok; Choi, Hyun Il

2011-01-01

There has been an increase in the occurrence of sudden local flooding of great volume and short duration caused by heavy or excessive rainfall intensity over a small area, which presents the greatest potential danger threat to the natural environment, human life, public health and property, etc. Such flash floods have rapid runoff and debris flow that rises quickly with little or no advance warning to prevent flood damage. This study develops a flash flood index through the average of the same scale relative severity factors quantifying characteristics of hydrographs generated from a rainfall-runoff model for the long-term observed rainfall data in a small ungauged study basin, and presents regression equations between rainfall characteristics and the flash flood index. The aim of this study is to develop flash flood index-duration-frequency relation curves by combining the rainfall intensity-duration-frequency relation and the flash flood index from probability rainfall data in order to evaluate vulnerability to extreme flash floods in design storms. This study is an initial effort to quantify the flash flood severity of design storms for both existing and planned flood control facilities to cope with residual flood risks due to extreme flash floods that have ocurred frequently in recent years. PMID:21845165

Factors Increasing Vulnerability to Health Effects before, during and after Floods

PubMed Central

Lowe, Dianne; Ebi, Kristie L.; Forsberg, Bertil

2013-01-01

Identifying the risk factors for morbidity and mortality effects pre-, during and post-flood may aid the appropriate targeting of flood-related adverse health prevention strategies. We conducted a systematic PubMed search to identify studies examining risk factors for health effects of precipitation-related floods, among Organisation for Economic Co-Operation and Development (OECD) member countries. Research identifying flood-related morbidity and mortality risk factors is limited and primarily examines demographic characteristics such as age and gender. During floods, females, elderly and children appear to be at greater risk of psychological and physical health effects, while males between 10 to 29 years may be at greater risk of mortality. Post-flood, those over 65 years and males are at increased risk of physical health effects, while females appear at greater risk of psychological health effects. Other risk factors include previous flood experiences, greater flood depth or flood trauma, existing illnesses, medication interruption, and low education or socio-economic status. Tailoring messages to high-risk groups may increase their effectiveness. Target populations differ for morbidity and mortality effects, and differ pre-, during, and post-flood. Additional research is required to identify the risk factors associated with pre- and post-flood mortality and post-flood morbidity, preferably using prospective cohort studies. PMID:24336027

Factors increasing vulnerability to health effects before, during and after floods.

PubMed

Lowe, Dianne; Ebi, Kristie L; Forsberg, Bertil

2013-12-11

Identifying the risk factors for morbidity and mortality effects pre-, during and post-flood may aid the appropriate targeting of flood-related adverse health prevention strategies. We conducted a systematic PubMed search to identify studies examining risk factors for health effects of precipitation-related floods, among Organisation for Economic Co-Operation and Development (OECD) member countries. Research identifying flood-related morbidity and mortality risk factors is limited and primarily examines demographic characteristics such as age and gender. During floods, females, elderly and children appear to be at greater risk of psychological and physical health effects, while males between 10 to 29 years may be at greater risk of mortality. Post-flood, those over 65 years and males are at increased risk of physical health effects, while females appear at greater risk of psychological health effects. Other risk factors include previous flood experiences, greater flood depth or flood trauma, existing illnesses, medication interruption, and low education or socio-economic status. Tailoring messages to high-risk groups may increase their effectiveness. Target populations differ for morbidity and mortality effects, and differ pre-, during, and post-flood. Additional research is required to identify the risk factors associated with pre- and post-flood mortality and post-flood morbidity, preferably using prospective cohort studies.

Assessment of vulnerability to extreme flash floods in design storms.

PubMed

Kim, Eung Seok; Choi, Hyun Il

2011-07-01

There has been an increase in the occurrence of sudden local flooding of great volume and short duration caused by heavy or excessive rainfall intensity over a small area, which presents the greatest potential danger threat to the natural environment, human life, public health and property, etc. Such flash floods have rapid runoff and debris flow that rises quickly with little or no advance warning to prevent flood damage. This study develops a flash flood index through the average of the same scale relative severity factors quantifying characteristics of hydrographs generated from a rainfall-runoff model for the long-term observed rainfall data in a small ungauged study basin, and presents regression equations between rainfall characteristics and the flash flood index. The aim of this study is to develop flash flood index-duration-frequency relation curves by combining the rainfall intensity-duration-frequency relation and the flash flood index from probability rainfall data in order to evaluate vulnerability to extreme flash floods in design storms. This study is an initial effort to quantify the flash flood severity of design storms for both existing and planned flood control facilities to cope with residual flood risks due to extreme flash floods that have ocurred frequently in recent years.

The world's largest floods, past and present: Their causes and magnitudes

USGS Publications Warehouse

O'Connor, Jim E.; Costa, John E.

2004-01-01

Floods are among the most powerful forces on earth. Human societies worldwide have lived and died with floods from the very beginning, spawning a prominent role for floods within legends, religions, and history. Inspired by such accounts, geologists, hydrologists, and historians have studied the role of floods on humanity and its supporting ecosystems, resulting in new appreciation for the many-faceted role of floods in shaping our world. Part of this appreciation stems from ongoing analysis of long-term streamflow measurements, such as those recorded by the U.S. Geological Survey's (USGS) streamflow gaging network. But the recognition of the important role of flooding in shaping our cultural and physical landscape also owes to increased understanding of the variety of mechanisms that cause floods and how the types and magnitudes of floods can vary with time and space. The USGS has contributed to this understanding through more than a century of diverse research activities on many aspects of floods, including their causes, effects, and hazards. This Circular summarizes a facet of this research by describing the causes and magnitudes of the world's largest floods, including those measured and described by modern methods in historic times, as well as floods of prehistoric times, for which the only records are those left by the floods themselves.

The August 1975 Flood over Central China

NASA Astrophysics Data System (ADS)

Yang, Long; Smith, James; Liu, Maofeng; Baeck, MaryLynn

2016-04-01

The August 1975 flood in Central China was one of the most destructive floods in history, resulting in 26 000 fatalities, leaving about 10 million people with insufficient shelter, and producing long-lasting famine and disease. Extreme rainfall responsible for this flood event was associated with typhoon Nina during 5-7 August 1975. Despite the prominence of the August 1975 flood, analyses of the storms producing the flood and the resulting flood are sparse. Even fewer attempts were made from the perspective of numerical simulations. We examine details of extreme rainfall for the August 1975 flood based on downscaling simulations using the Weather Research and Forecasting (WRF) model driven by 20th Century Reanalysis fields. We further placed key hydrometeorological features for the flood event in a climatological context through the analyses of the 20th Century Reanalysis fields. Results indicate interrelated roles of multiple mesoscale ingredients for deep, moist convection in producing extreme rainfall for the August 1975 flood, superimposed over an anomalous synoptic environment. Attribution analyses on the source of water vapor for this flood event will be conducted based on a Lagrangian parcel tracking algorithm LAGRANTO. Analytical framework developed in this study aims to explore utilization of hydrometeorological approach in flood-control engineering designs by providing details on key elements of flood-producing storms.

Impacts of flood damage on airborne bacteria and fungi in homes after the 2013 Colorado Front Range flood.

PubMed

Emerson, Joanne B; Keady, Patricia B; Brewer, Tess E; Clements, Nicholas; Morgan, Emily E; Awerbuch, Jonathan; Miller, Shelly L; Fierer, Noah

2015-03-03

Flood-damaged homes typically have elevated microbial loads, and their occupants have an increased incidence of allergies, asthma, and other respiratory ailments, yet the microbial communities in these homes remain under-studied. Using culture-independent approaches, we characterized bacterial and fungal communities in homes in Boulder, CO, USA 2-3 months after the historic September, 2013 flooding event. We collected passive air samples from basements in 50 homes (36 flood-damaged, 14 non-flooded), and we sequenced the bacterial 16S rRNA gene (V4-V5 region) and the fungal ITS1 region from these samples for community analyses. Quantitative PCR was used to estimate the abundances of bacteria and fungi in the passive air samples. Results indicate significant differences in bacterial and fungal community composition between flooded and non-flooded homes. Fungal abundances were estimated to be three times higher in flooded, relative to non-flooded homes, but there were no significant differences in bacterial abundances. Penicillium (fungi) and Pseudomonadaceae and Enterobacteriaceae (bacteria) were among the most abundant taxa in flooded homes. Our results suggest that bacterial and fungal communities continue to be affected by flooding, even after relative humidity has returned to baseline levels and remediation has removed any visible evidence of flood damage.

Analysis of regional natural flow for evaluation of flood risk according to RCP climate change scenarios

NASA Astrophysics Data System (ADS)

Lee, J. Y.; Chae, B. S.; Wi, S.; KIm, T. W.

2017-12-01

Various climate change scenarios expect the rainfall in South Korea to increase by 3-10% in the future. The future increased rainfall has significant effect on the frequency of flood in future as well. This study analyzed the probability of future flood to investigate the stability of existing and new installed hydraulic structures and the possibility of increasing flood damage in mid-sized watersheds in South Korea. To achieve this goal, we first clarified the relationship between flood quantiles acquired from the flood-frequency analysis (FFA) and design rainfall-runoff analysis (DRRA) in gauged watersheds. Then, after synthetically generating the regional natural flow data according to RCP climate change scenarios, we developed mathematical formulas to estimate future flood quantiles based on the regression between DRRA and FFA incorporated with regional natural flows in unguaged watersheds. Finally, we developed a flood risk map to investigate the change of flood risk in terms of the return period for the past, present, and future. The results identified that the future flood quantiles and risks would increase in accordance with the RCP climate change scenarios. Because the regional flood risk was identified to increase in future comparing with the present status, comprehensive flood control will be needed to cope with extreme floods in future.

Influence of flood risk characteristics on flood insurance demand: a comparison between Germany and the Netherlands

NASA Astrophysics Data System (ADS)

Seifert, I.; Botzen, W. J. W.; Kreibich, H.; Aerts, J. C. J. H.

2013-07-01

The existence of sufficient demand for insurance coverage against infrequent losses is important for the adequate function of insurance markets for natural disaster risks. This study investigates how characteristics of flood risk influence household flood insurance demand based on household surveys undertaken in Germany and the Netherlands. Our analyses confirm the hypothesis that willingness to pay (WTP) for insurance against medium-probability medium-impact flood risk in Germany is higher than WTP for insurance against low-probability high-impact flood risk in the Netherlands. These differences in WTP can be related to differences in flood experience, individual risk perceptions, and the charity hazard. In both countries there is a need to stimulate flood insurance demand if a relevant role of private insurance in flood loss compensation is regarded as desirable, for example, by making flood insurance compulsory or by designing information campaigns.

Seasonal characteristics of flood regimes across the Alpine-Carpathian range.

PubMed

Parajka, J; Kohnová, S; Bálint, G; Barbuc, M; Borga, M; Claps, P; Cheval, S; Dumitrescu, A; Gaume, E; Hlavčová, K; Merz, R; Pfaundler, M; Stancalie, G; Szolgay, J; Blöschl, G

2010-11-17

The aim of this paper is to analyse the differences in the long-term regimes of extreme precipitation and floods across the Alpine-Carpathian range using seasonality indices and atmospheric circulation patterns to understand the main flood-producing processes. This is supported by cluster analyses to identify areas of similar flood processes, both in terms of precipitation forcing and catchment processes. The results allow to isolate regions of similar flood generation processes including southerly versus westerly circulation patterns, effects of soil moisture seasonality due to evaporation and effects of soil moisture seasonality due to snow melt. In many regions of the Alpine-Carpathian range, there is a distinct shift in flood generating processes with flood magnitude as evidenced by a shift from summer to autumn floods. It is argued that the synoptic approach proposed here is valuable in both flood analysis and flood estimation.

Seasonal characteristics of flood regimes across the Alpine–Carpathian range

PubMed Central

Parajka, J.; Kohnová, S.; Bálint, G.; Barbuc, M.; Borga, M.; Claps, P.; Cheval, S.; Dumitrescu, A.; Gaume, E.; Hlavčová, K.; Merz, R.; Pfaundler, M.; Stancalie, G.; Szolgay, J.; Blöschl, G.

2010-01-01

Summary The aim of this paper is to analyse the differences in the long-term regimes of extreme precipitation and floods across the Alpine–Carpathian range using seasonality indices and atmospheric circulation patterns to understand the main flood-producing processes. This is supported by cluster analyses to identify areas of similar flood processes, both in terms of precipitation forcing and catchment processes. The results allow to isolate regions of similar flood generation processes including southerly versus westerly circulation patterns, effects of soil moisture seasonality due to evaporation and effects of soil moisture seasonality due to snow melt. In many regions of the Alpine–Carpathian range, there is a distinct shift in flood generating processes with flood magnitude as evidenced by a shift from summer to autumn floods. It is argued that the synoptic approach proposed here is valuable in both flood analysis and flood estimation. PMID:25067854

Temporal clustering of floods in Germany: Do flood-rich and flood-poor periods exist?

NASA Astrophysics Data System (ADS)

Merz, Bruno; Nguyen, Viet Dung; Vorogushyn, Sergiy

2016-10-01

The repeated occurrence of exceptional floods within a few years, such as the Rhine floods in 1993 and 1995 and the Elbe and Danube floods in 2002 and 2013, suggests that floods in Central Europe may be organized in flood-rich and flood-poor periods. This hypothesis is studied by testing the significance of temporal clustering in flood occurrence (peak-over-threshold) time series for 68 catchments across Germany for the period 1932-2005. To assess the robustness of the results, different methods are used: Firstly, the index of dispersion, which quantifies the departure from a homogeneous Poisson process, is investigated. Further, the time-variation of the flood occurrence rate is derived by non-parametric kernel implementation and the significance of clustering is evaluated via parametric and non-parametric tests. Although the methods give consistent overall results, the specific results differ considerably. Hence, we recommend applying different methods when investigating flood clustering. For flood estimation and risk management, it is of relevance to understand whether clustering changes with flood severity and time scale. To this end, clustering is assessed for different thresholds and time scales. It is found that the majority of catchments show temporal clustering at the 5% significance level for low thresholds and time scales of one to a few years. However, clustering decreases substantially with increasing threshold and time scale. We hypothesize that flood clustering in Germany is mainly caused by catchment memory effects along with intra- to inter-annual climate variability, and that decadal climate variability plays a minor role.

Flood of April 1975 at Williamston, Michigan

USGS Publications Warehouse

Knutilla, R.L.; Swallow, L.A.

1975-01-01

On April 18 between 5 p.m. and 12 p.m. the city of Williamston experienced an intense rain storm that caused the Red Cedar River and the many small streams in the area to overflow their banks and resulted in the most devastating flood since at least 1904. Local officials estimated a loss of \\$775,000 in property damage. Damage from flooding by the Red Cedar River was caused primarily by inundation, rather than by water moving at high velocity, as is common when many streams are flooded. During the flood of April 1975 many basements were flooded as well as the lower floors of some homes in the flood plain. Additional damage occurred in places when sewers backed up and flooded basements, and when ground water seeped through basement walls and floors—situations that affected many homes including those that were well outside of the flood plain.During the time of flooding the U.S. Geological Survey obtained aerial photography and data on a streamflow to document the disaster. This report shows on a photomosaic base map the extent of flooding along the Red Cedar River at Williamston, during the flood. It also presents data obtained at stream-gaging stations near Williamston, as well as the results of peak-flow discharge measurements made on the Red Cedar River at Michigan State Highway M-52 east of the city. Information on the magnitude of the flood can guide in making decisions pertaining to the use of flood-plains in the area. It is one of a series of reports on the April 1975 flood in the Lansing metropolitan area.

Characteristics of the April 2007 Flood at 10 Streamflow-Gaging Stations in Massachusetts

USGS Publications Warehouse

Zarriello, Phillip J.; Carlson, Carl S.

2009-01-01

A large 'nor'easter' storm on April 15-18, 2007, brought heavy rains to the southern New England region that, coupled with normal seasonal high flows and associated wet soil-moisture conditions, caused extensive flooding in many parts of Massachusetts and neighboring states. To characterize the magnitude of the April 2007 flood, a peak-flow frequency analysis was undertaken at 10 selected streamflow-gaging stations in Massachusetts to determine the magnitude of flood flows at 5-, 10-, 25-, 50-, 100-, 200-, and 500-year return intervals. The magnitude of flood flows at various return intervals were determined from the logarithms of the annual peaks fit to a Pearson Type III probability distribution. Analysis included augmenting the station record with longer-term records from one or more nearby stations to provide a common period of comparison that includes notable floods in 1936, 1938, and 1955. The April 2007 peak flow was among the highest recorded or estimated since 1936, often ranking between the 3d and 5th highest peak for that period. In general, the peak-flow frequency analysis indicates the April 2007 peak flow has an estimated return interval between 25 and 50 years; at stations in the northeastern and central areas of the state, the storm was less severe resulting in flows with return intervals of about 5 and 10 years, respectively. At Merrimack River at Lowell, the April 2007 peak flow approached a 100-year return interval that was computed from post-flood control records and the 1936 and 1938 peak flows adjusted for flood control. In general, the magnitude of flood flow for a given return interval computed from the streamflow-gaging station period-of-record was greater than those used to calculate flood profiles in various community flood-insurance studies. In addition, the magnitude of the updated flood flow and current (2008) stage-discharge relation at a given streamflow-gaging station often produced a flood stage that was considerably different than the flood stage indicated in the flood-insurance study flood profile at that station. Equations for estimating the flow magnitudes for 5-, 10-, 25-, 50-, 100-, 200-, and 500-year floods were developed from the relation of the magnitude of flood flows to drainage area calculated from the six streamflow-gaging stations with the longest unaltered record. These equations produced a more conservative estimate of flood flows (higher discharges) than the existing regional equations for estimating flood flows at ungaged rivers in Massachusetts. Large differences in the magnitude of flood flows for various return intervals determined in this study compared to results from existing regional equations and flood insurance studies indicate a need for updating regional analyses and equations for estimating the expected magnitude of flood flows in Massachusetts.

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

NASA Astrophysics Data System (ADS)

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 perception of risk and, consequently, people preparedness remains high. Conversely, long periods without floods will serve to diminish awareness, since the memory of floods tends to be short (i.e., people tend to forget quickly), finally leading communities to take too high risks. Di Baldassarre, G., A. Viglione, G. Carr, L. Kuil, J.L. Salinas and G. Blöschl (2013) Socio-hydrology: conceptualising human-flood interactions, Hydrology and Earth System Sciences, 17, 3295-3303, doi:10.5194/hess-17-3295-2013. Viglione, A., G. Di Baldassarre, L. Brandimarte, L. Kuil, G. Carr, J.L. Salinas, A. Scolobig and G. Blöschl (2013) Insights from socio-hydrology modelling on dealing with flood risk: roles of collective memory, risk-taking attitude and trust, Journal of Hydrology, accepted.

Anthropogenic impact on flood-risk: a large-scale assessment for planning controlled inundation strategies along the River Po

NASA Astrophysics Data System (ADS)

Domeneghetti, Alessio; Castellarin, Attilio; Brath, Armando

2013-04-01

The European Flood Directive (2007/60/EC) has fostered the development of innovative and sustainable approaches and methodologies for flood-risk mitigation and management. Furthermore, concerning flood-risk mitigation, the increasing awareness of how the anthropogenic pressures (e.g. demographic and land-use dynamics, uncontrolled urban and industrial expansion on flood-prone area) could strongly increase potential flood damages and losses has triggered a paradigm shift from "defending the territory against flooding" (e.g. by means of levee system strengthening and heightening) to "living with floods" (e.g. promoting compatible land-uses or adopting controlled flooding strategies of areas located outside the main embankments). The assessment of how socio-economic dynamics may influence flood-risk represents a fundamental skill that should be considered for planning a sustainable industrial and urban development of flood-prone areas, reducing their vulnerability and therefore minimizing socio-economic and ecological losses due to large flood events. These aspects, which are of fundamental importance for Institutions and public bodies in charge of Flood Directive requirements, need to be considered through a holistic approach at river basin scale. This study focuses on the evaluation of large-scale flood-risk mitigation strategies for the middle-lower reach of River Po (~350km), the longest Italian river and the largest in terms of streamflow. Due to the social and economical importance of the Po River floodplain (almost 40% of the total national gross product results from this area), our study aims at investigating the potential of combining simplified vulnerability indices with a quasi-2D model for the definition of sustainable and robust flood-risk mitigation strategies. Referring to past (1954) and recent (2006) land-use data sets (e.g. CORINE) we propose simplified vulnerability indices for assessing potential flood-risk of industrial and urbanized flood prone areas taking into account altimetry and population density, and we analyze the modification of flood-risk occurred during last decades due to the demographic dynamics of the River Po floodplains. Flood hazard associated to a high magnitude event (i.e. return period of about 500 year) was estimated by means of a quasi-2D hydraulic model set up for the middle-lower portion of the Po River and for its major tributaries. The results of the study highlight how coupling a large-scale numerical model with the proposed flood-vulnerability indices could be a useful tool for decision-makers when they are called to define sustainable spatial development plans for the study area, or when they need to identify priorities in the organization of civil protection actions during a major flood event that could include the necessity of controlled flooding of flood-prone areas located outside the main embankment system.

44 CFR 65.14 - Remapping of areas for which local flood protection systems no longer provide base flood protection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... local flood protection systems no longer provide base flood protection. 65.14 Section 65.14 Emergency... § 65.14 Remapping of areas for which local flood protection systems no longer provide base flood protection. (a) General. (1) This section describes the procedures to follow and the types of information...

44 CFR 65.14 - Remapping of areas for which local flood protection systems no longer provide base flood protection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... local flood protection systems no longer provide base flood protection. 65.14 Section 65.14 Emergency... § 65.14 Remapping of areas for which local flood protection systems no longer provide base flood protection. (a) General. (1) This section describes the procedures to follow and the types of information...

44 CFR 65.14 - Remapping of areas for which local flood protection systems no longer provide base flood protection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... local flood protection systems no longer provide base flood protection. 65.14 Section 65.14 Emergency... § 65.14 Remapping of areas for which local flood protection systems no longer provide base flood protection. (a) General. (1) This section describes the procedures to follow and the types of information...

SERVIR-Africa: Developing an Integrated Platform for Floods Disaster Management in Africa

NASA Technical Reports Server (NTRS)

Macharia, Daniel; Korme, Tesfaye; Policelli, Fritz; Irwin, Dan; Adler, Bob; Hong, Yang

2010-01-01

SERVIR-Africa is an ambitious regional visualization and monitoring system that integrates remotely sensed data with predictive models and field-based data to monitor ecological processes and respond to natural disasters. It aims addressing societal benefits including floods and turning data into actionable information for decision-makers. Floods are exogenous disasters that affect many parts of Africa, probably second only to drought in terms of social-economic losses. This paper looks at SERVIR-Africa's approach to floods disaster management through establishment of an integrated platform, floods prediction models, post-event flood mapping and monitoring as well as flood maps dissemination in support of flood disaster management.

The Incidence of Posttraumatic Stress Disorder After Floods: A Meta-Analysis.

PubMed

Chen, Long; Liu, Aizhong

2015-06-01

This study analyzes the incidence of posttraumatic stress disorder (PTSD) among flood victims, between different flood intensities, and between different time points after a flood. A search of several electronic literature databases was conducted to collect data on the incidence of PTSD after a flood. Loney criteria for research quality were used to evaluate the quality of selected search results. The combined incidence of PTSD was estimated using the Freeman-Tukey double arcsine transformation method. Subgroup analyses were conducted on different trauma intensities and different time points after a flood. Sensitivity analysis was performed to evaluate the impact of research quality. Fourteen articles were included in this meta-analysis, including a total of 40 600 flood victims; 3862 victims were diagnosed with PTSD. The combined incidence of PTSD was 15.74%. The subgroup analyses showed that the incidence of PTSD in victims who experienced severe and moderate flood intensity was higher than that in victims who experienced mild flood intensity. The incidence of PTSD was lower at 6 or more months after a flood (11.45%) than within 6 months (16.01%) of a flood. In conclusion, the incidence of PTSD among floods of different trauma intensities was statistically significant.

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

NASA Astrophysics Data System (ADS)

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.

Application of satellite products and hydrological modelling for flood early warning

NASA Astrophysics Data System (ADS)

Koriche, Sifan A.; Rientjes, Tom H. M.

2016-06-01

Floods have caused devastating impacts to the environment and society in Awash River Basin, Ethiopia. Since flooding events are frequent, this marks the need to develop tools for flood early warning. In this study, we propose a satellite based flood index to identify the runoff source areas that largely contribute to extreme runoff production and floods in the basin. Satellite based products used for development of the flood index are CMORPH (Climate Prediction Center MORPHing technique: 0.25° by 0.25°, daily) product for calculation of the Standard Precipitation Index (SPI) and a Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) for calculation of the Topographic Wetness Index (TWI). Other satellite products used in this study are for rainfall-runoff modelling to represent rainfall, potential evapotranspiration, vegetation cover and topography. Results of the study show that assessment of spatial and temporal rainfall variability by satellite products may well serve in flood early warning. Preliminary findings on effectiveness of the flood index developed in this study indicate that the index is well suited for flood early warning. The index combines SPI and TWI, and preliminary results illustrate the spatial distribution of likely runoff source areas that cause floods in flood prone areas.

floodX: urban flash flood experiments monitored with conventional and alternative sensors

NASA Astrophysics Data System (ADS)

Moy de Vitry, Matthew; Dicht, Simon; Leitão, João P.

2017-09-01

The data sets described in this paper provide a basis for developing and testing new methods for monitoring and modelling urban pluvial flash floods. Pluvial flash floods are a growing hazard to property and inhabitants' well-being in urban areas. However, the lack of appropriate data collection methods is often cited as an impediment for reliable flood modelling, thereby hindering the improvement of flood risk mapping and early warning systems. The potential of surveillance infrastructure and social media is starting to draw attention for this purpose. In the floodX project, 22 controlled urban flash floods were generated in a flood response training facility and monitored with state-of-the-art sensors as well as standard surveillance cameras. With these data, it is possible to explore the use of video data and computer vision for urban flood monitoring and modelling. The floodX project stands out as the largest documented flood experiment of its kind, providing both conventional measurements and video data in parallel and at high temporal resolution. The data set used in this paper is available at https://doi.org/10.5281/zenodo.830513.

Palaeoflood hydrology in Europe: towards a better understanding of extreme floods

NASA Astrophysics Data System (ADS)

Benito, G.; Thorndycraft, V. R.; Rico, M.; Sheffer, N.; Enzel, Y.

2003-04-01

Floods are the most common natural disasters in Europe and, in terms of economic damage, costs are increasing spectacularly with time. Flood risk assessment associated with extreme floods is difficult due to the scarcity of hydrological measurements, that rarely go beyond 1000 years, which is clearly not sufficient for flood management in urban and industrial areas. Besides the use of conventional hydrologic data, the pre-instrumental record can be completed from palaeoflood hydrology or from documentary flood information, or through the combined use of both these tools. Recent developments of palaeoflood hydrology in Europe provide (1) major improvements in flood risk assessment, and (2) a better understanding of long-term flood-climate relationships. Palaeoflood hydrology has been successfully applied in large, medium rivers as well as small ungauged mountain drainage basins. Long-term palaeoflood records from Spain and France show that recent extraordinary flooding (causing huge economic damages) are not the largest ones, but that similar or even greater floods occurred several times in the past. In addition, clusters of floods coinciding in time at several European rivers point out to climatic factors as responsible mechanisms, although in recent time flood magnitude can be magnified by increasing human activity.

Global-scale river flood vulnerability in the last 50 years.

PubMed

Tanoue, Masahiro; Hirabayashi, Yukiko; Ikeuchi, Hiroaki

2016-10-26

The impacts of flooding are expected to rise due to population increases, economic growth and climate change. Hence, understanding the physical and spatiotemporal characteristics of risk drivers (hazard, exposure and vulnerability) is required to develop effective flood mitigation measures. Here, the long-term trend in flood vulnerability was analysed globally, calculated from the ratio of the reported flood loss or damage to the modelled flood exposure using a global river and inundation model. A previous study showed decreasing global flood vulnerability over a shorter period using different disaster data. The long-term analysis demonstrated for the first time that flood vulnerability to economic losses in upper-middle, lower-middle and low-income countries shows an inverted U-shape, as a result of the balance between economic growth and various historical socioeconomic efforts to reduce damage, leading to non-significant upward or downward trends. We also show that the flood-exposed population is affected by historical changes in population distribution, with changes in flood vulnerability of up to 48.9%. Both increasing and decreasing trends in flood vulnerability were observed in different countries, implying that population growth scenarios considering spatial distribution changes could affect flood risk projections.

Global-scale river flood vulnerability in the last 50 years

PubMed Central

Tanoue, Masahiro; Hirabayashi, Yukiko; Ikeuchi, Hiroaki

2016-01-01

The impacts of flooding are expected to rise due to population increases, economic growth and climate change. Hence, understanding the physical and spatiotemporal characteristics of risk drivers (hazard, exposure and vulnerability) is required to develop effective flood mitigation measures. Here, the long-term trend in flood vulnerability was analysed globally, calculated from the ratio of the reported flood loss or damage to the modelled flood exposure using a global river and inundation model. A previous study showed decreasing global flood vulnerability over a shorter period using different disaster data. The long-term analysis demonstrated for the first time that flood vulnerability to economic losses in upper-middle, lower-middle and low-income countries shows an inverted U-shape, as a result of the balance between economic growth and various historical socioeconomic efforts to reduce damage, leading to non-significant upward or downward trends. We also show that the flood-exposed population is affected by historical changes in population distribution, with changes in flood vulnerability of up to 48.9%. Both increasing and decreasing trends in flood vulnerability were observed in different countries, implying that population growth scenarios considering spatial distribution changes could affect flood risk projections. PMID:27782160

Beyond 'flood hotspots': Modelling emergency service accessibility during flooding in York, UK

NASA Astrophysics Data System (ADS)

Coles, Daniel; Yu, Dapeng; Wilby, Robert L.; Green, Daniel; Herring, Zara

2017-03-01

This paper describes the development of a method that couples flood modelling with network analysis to evaluate the accessibility of city districts by emergency responders during flood events. We integrate numerical modelling of flood inundation with geographical analysis of service areas for the Ambulance Service and the Fire & Rescue Service. The method was demonstrated for two flood events in the City of York, UK to assess the vulnerability of care homes and sheltered accommodation. We determine the feasibility of emergency services gaining access within the statutory 8- and 10-min targets for high-priority, life-threatening incidents 75% of the time, during flood episodes. A hydrodynamic flood inundation model (FloodMap) simulates the 2014 pluvial and 2015 fluvial flood events. Predicted floods (with depth >25 cm and areas >100 m2) were overlain on the road network to identify sites with potentially restricted access. Accessibility of the city to emergency responders during flooding was quantified and mapped using; (i) spatial coverage from individual emergency nodes within the legislated timeframes, and; (ii) response times from individual emergency service nodes to vulnerable care homes and sheltered accommodation under flood and non-flood conditions. Results show that, during the 2015 fluvial flood, the area covered by two of the three Fire & Rescue Service stations reduced by 14% and 39% respectively, while the remaining station needed to increase its coverage by 39%. This amounts to an overall reduction of 6% and 20% for modelled and observed floods respectively. During the 2014 surface water flood, 7 out of 22 care homes (32%) and 15 out of 43 sheltered accommodation nodes (35%) had modelled response times above the 8-min threshold from any Ambulance station. Overall, modelled surface water flooding has a larger spatial footprint than fluvial flood events. Hence, accessibility of emergency services may be impacted differently depending on flood mechanism. Moreover, we expect emergency services to face greater challenges under a changing climate with a growing, more vulnerable population. The methodology developed in this study could be applied to other cities, as well as for scenario-based evaluation of emergency preparedness to support strategic decision making, and in real-time forecasting to guide operational decisions where heavy rainfall lead-time and spatial resolution are sufficient.

Estimated flood-inundation maps for Cowskin Creek in western Wichita, Kansas

USGS Publications Warehouse

Studley, Seth E.

2003-01-01

The October 31, 1998, flood on Cowskin Creek in western Wichita, Kansas, caused millions of dollars in damages. Emergency management personnel and flood mitigation teams had difficulty in efficiently identifying areas affected by the flooding, and no warning was given to residents because flood-inundation information was not available. To provide detailed information about future flooding on Cowskin Creek, high-resolution estimated flood-inundation maps were developed using geographic information system technology and advanced hydraulic analysis. Two-foot-interval land-surface elevation data from a 1996 flood insurance study were used to create a three-dimensional topographic representation of the study area for hydraulic analysis. The data computed from the hydraulic analyses were converted into geographic information system format with software from the U.S. Army Corps of Engineers' Hydrologic Engineering Center. The results were overlaid on the three-dimensional topographic representation of the study area to produce maps of estimated flood-inundation areas and estimated depths of water in the inundated areas for 1-foot increments on the basis of stream stage at an index streamflow-gaging station. A Web site (http://ks.water.usgs.gov/Kansas/cowskin.floodwatch) was developed to provide the public with information pertaining to flooding in the study area. The Web site shows graphs of the real-time streamflow data for U.S. Geological Survey gaging stations in the area and monitors the National Weather Service Arkansas-Red Basin River Forecast Center for Cowskin Creek flood-forecast information. When a flood is forecast for the Cowskin Creek Basin, an estimated flood-inundation map is displayed for the stream stage closest to the National Weather Service's forecasted peak stage. Users of the Web site are able to view the estimated flood-inundation maps for selected stages at any time and to access information about this report and about flooding in general. Flood recovery teams also have the ability to view the estimated flood-inundation map pertaining to the most recent flood. The availability of these maps and the ability to monitor the real-time stream stage through the U.S. Geological Survey Web site provide emergency management personnel and residents with information that is critical for evacuation and rescue efforts in the event of a flood as well as for post-flood recovery efforts.

Epic Flooding in Georgia, 2009

USGS Publications Warehouse

Gotvald, Anthony J.; McCallum, Brian E.

2010-01-01

Metropolitan Atlanta-September 2009 Floods The epic floods experienced in the Atlanta area in September 2009 were extremely rare. Eighteen streamgages in the Metropolitan Atlanta area had flood magnitudes much greater than the estimated 0.2-percent (500-year) annual exceedance probability. The Federal Emergency Management Agency (FEMA) reported that 23 counties in Georgia were declared disaster areas due to this flood and that 16,981 homes and 3,482 businesses were affected by floodwaters. Ten lives were lost in the flood. The total estimated damages exceed $193 million (H.E. Longenecker, Federal Emergency Management Agency, written commun., November 2009). On Sweetwater Creek near Austell, Ga., just north of Interstate 20, the peak stage was more than 6 feet higher than the estimated peak stage of the 0.2-percent (500-year) flood. Flood magnitudes in Cobb County on Sweetwater, Butler, and Powder Springs Creeks greatly exceeded the estimated 0.2-percent (500-year) floods for these streams. In Douglas County, the Dog River at Ga. Highway 5 near Fairplay had a peak stage nearly 20 feet higher than the estimated peak stage of the 0.2-percent (500-year) flood. On the Chattahoochee River, the U.S. Geological Survey (USGS) gage at Vinings reached the highest level recorded in the past 81 years. Gwinnett, De Kalb, Fulton, and Rockdale Counties also had record flooding.South Georgia March and April 2009 FloodsThe March and April 2009 floods in South Georgia were smaller in magnitude than the September floods but still caused significant damage. No lives were lost in this flood. Approximately $60 million in public infrastructure damage occurred to roads, culverts, bridges and a water treatment facility (Joseph T. McKinney, Federal Emergency Management Agency, written commun., July 2009). Flow at the Satilla River near Waycross, exceeded the 0.5-percent (200-year) flood. Flows at seven other stations in South Georgia exceeded the 1-percent (100-year) flood.

A prediction and damage assessment model for snowmelt flood events in middle and high latitudes Region

NASA Astrophysics Data System (ADS)

Qiao, C.; Huang, Q.; Chen, T.; Zhang, X.

2017-12-01

In the context of global warming, the snowmelt flood events in the mountainous area of the middle and high latitudes are increasingly frequent and create severe casualties and property damages. Carrying out the prediction and risk assessment of the snowmelt flood is of great importance in the water resources management, the flood warning and prevention. Based on the remote sensing and GIS techniques, the relationships of the variables influencing the snowmelt flood such as the snow area, the snow depth, the air temperature, the precipitation, the land topography and land covers are analyzed and a prediction and damage assessment model for snowmelt floods is developed. This model analyzes and predicts the flood submerging area, flood depth, flood grade, and the damages of different underlying surfaces in the study area in a given time period based on the estimation of snowmelt amount, the snowmelt runoff, the direction and velocity of the flood. Then it was used to predict a snowmelt flood event in the Ertis River Basin in northern Xinjiang, China, during March and June, 2005 and to assess its damages including the damages of roads, transmission lines, settlements caused by the floods and the possible landslides using the hydrological and meteorological data, snow parameter data, DEM data and land use data. A comparison was made between the prediction results from this model and observation data including the flood measurement and its disaster loss data, which suggests that this model performs well in predicting the strength and impact area of snowmelt flood and its damage assessment. This model will be helpful for the prediction and damage assessment of snowmelt flood events in the mountainous area in the middle and high latitudes in spring, which has great social and economic significance because it provides a relatively reliable method for snowmelt flood prediction and reduces the possible damages caused by snowmelt floods.

Evaluation of urban flood damages in climate and land use changes: Case Studies from Southeast Asia

NASA Astrophysics Data System (ADS)

Kefi, M.; Binaya, M. K.; Kumar, P.; Fukushi, K.

2017-12-01

Urbanization, changes in land use and global warming increase the threat of natural disasters such as flooding. In recent decades, it was observed a rise of intensity and frequency of flood events. The exposure both of people and the national economy to flood hazards is amplified and can induce serious economic and social damages. For this reason, local governments adopted several strategies to cope with flood risk in urban areas in particular, but a better comprehension of the flood hazard factors may enhance the efficiency of mitigating measures overall. For this research, a spatial analysis is applied to estimate future direct flood damage for 2030 in three Southeast Asian megacities: Jakarta (Indonesia), Metro-Manila (Philippines) and Hanoi (Vietnam). This comprehensive method combined flood characteristics (flood depth) obtained from flood simulation using FLO-2D, land use generated from supervised classification and remote sensing products, property value of affected buildings and flood damage rate derived from flood depth function. This function is established based on field surveys with local people affected by past flood events. Additionally, two scenarios were analyzed to simulate the future conditions. The first one is related to climate change and it is based on several General Circulation Models (GCMs). However, the second one is establish to point out the effect of adaptation strategies. The findings shows that the climate change combined with the expansion of built-up areas increase the vulnerability of urban areas to flooding and the economic damage. About 16%, 8% and 19% of flood inundation areas are expected to increase respectively in Metro-Manila, Jakarta and Hanoi. However, appropriate flood control measures can be helpful to reduce the impact of natural disaster. Furthermore, flood damage maps are generated at a large scale, which can be helpful to local stakeholders when prioritizing their mitigation strategies on urban disaster resilience.

Utah Flooding Hazard: Raising Public Awareness through the Creation of Multidisciplinary Web-Based Maps

NASA Astrophysics Data System (ADS)

Castleton, J.; Erickson, B.; Bowman, S. D.; Unger, C. D.

2014-12-01

The Utah Geological Survey's (UGS) Geologic Hazards Program has partnered with the U.S. Army Corps of Engineers to create geologically derived web-based flood hazard maps. Flooding in Utah communities has historically been one of the most damaging geologic hazards. The most serious floods in Utah have generally occurred in the Great Salt Lake basin, particularly in the Weber River drainage on the western slopes of the Wasatch Range, in areas of high population density. With a growing population of 2.9 million, the state of Utah is motivated to raise awareness about the potential for flooding. The process of increasing community resiliency to flooding begins with identification and characterization of flood hazards. Many small communities in areas experiencing rapid growth have not been mapped completely by the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRM). Existing FIRM maps typically only consider drainage areas that are greater than one square mile in determining flood zones and do not incorporate geologic data, such as the presence of young, geologically active alluvial fans that indicate a high potential for debris flows and sheet flooding. Our new flood hazard mapping combines and expands on FEMA data by incorporating mapping derived from 1:24,000-scale UGS geologic maps, LiDAR data, digital elevation models, and historical aerial photography. Our flood hazard maps are intended to supplement the FIRM maps to provide local governments and the public with additional flood hazard information so they may make informed decisions, ultimately reducing the risk to life and property from flooding hazards. Flooding information must be widely available and easily accessed. One of the most effective ways to inform the public is through web-based maps. Web-based flood hazard maps will not only supply the public with the flood information they need, but also provides a platform to add additional geologic hazards to an easily accessible format.

How frequently will the Surface Water and Ocean Topography (SWOT) observe floods?

NASA Astrophysics Data System (ADS)

Frasson, R. P. M.; Schumann, G.

2017-12-01

The SWOT mission will measure river width and water surface elevations of rivers wider than 100 m. As the data gathered by this mission will be freely available, it can be of great use for flood modeling, especially in areas where streamgage networks are exceedingly sparse, or when data sharing barriers prevent the timely access to information. Despite having world-wide coverage, SWOT's temporal sampling is limited, with most locations being revisited once or twice every 21 days. Our objective is to evaluate which fraction of world-wide floods SWOT will observe and how many observations per event the satellite will likely obtain. We take advantage of the extensive database of floods constructed by the Dartmouth Flood Observatory, who, since 1985, searches through news sources and governmental agencies, and more recently remote sensing imagery for flood information, including flood duration, location and affected area. We cross-referenced the flood locations in the DFO archive with the SWOT prototype prior database of river centerlines and the anticipated satellite's orbit to identify how many of the SWOT swaths were located within 10 km, 20 km, and 50 km from a flood centroid. Subsequently, we estimated the probability that SWOT would have at least one observation of a flood event per distance bin by multiplying the number of swaths in the distance bin by the flood duration divided by the SWOT orbit repeat period. Our analysis contemplated 132 world-wide floods recorded between May 2016 and May 2017. From these, 29, 52, and 86 floods had at least a 50% probability of having one overpass within 10 km, 20 km, and 50 km respectively. Moreover, after excluding flood events with no river centerlines within 10 km of its centroid, the average number of swaths within 10 km of a flood centroid was 1.79, indicating that in the 37 flood events that were likely caused by river flooding, at least one measurement was guaranteed to happen during the event.

Urban flood early warning systems: approaches to hydrometeorological forecasting and communicating risk

NASA Astrophysics Data System (ADS)

Cranston, Michael; Speight, Linda; Maxey, Richard; Tavendale, Amy; Buchanan, Peter

2015-04-01

One of the main challenges for the flood forecasting community remains the provision of reliable early warnings of surface (or pluvial) flooding. The Scottish Flood Forecasting Service has been developing approaches for forecasting the risk of surface water flooding including capitalising on the latest developments in quantitative precipitation forecasting from the Met Office. A probabilistic Heavy Rainfall Alert decision support tool helps operational forecasters assess the likelihood of surface water flooding against regional rainfall depth-duration estimates from MOGREPS-UK linked to historical short-duration flooding in Scotland. The surface water flood risk is communicated through the daily Flood Guidance Statement to emergency responders. A more recent development is an innovative risk-based hydrometeorological approach that links 24-hour ensemble rainfall forecasts through a hydrological model (Grid-to-Grid) to a library of impact assessments (Speight et al., 2015). The early warning tool - FEWS Glasgow - presents the risk of flooding to people, property and transport across a 1km grid over the city of Glasgow with a lead time of 24 hours. Communication of the risk was presented in a bespoke surface water flood forecast product designed based on emergency responder requirements and trialled during the 2014 Commonwealth Games in Glasgow. The development of new approaches to surface water flood forecasting are leading to improved methods of communicating the risk and better performance in early warning with a reduction in false alarm rates with summer flood guidance in 2014 (67%) compared to 2013 (81%) - although verification of instances of surface water flooding remains difficult. However the introduction of more demanding hydrometeorological capabilities with associated greater levels of uncertainty does lead to an increased demand on operational flood forecasting skills and resources. Speight, L., Cole, S.J., Moore, R.J., Pierce, C., Wright, B., Golding, B., Cranston, M., Tavendale, A., Ghimire, S., and Dhondia, J. (2015) Developing surface water flood forecasting capabilities in Scotland: an operational pilot for the 2014 Commonwealth Games in Glasgow. Journal of Flood Risk Management, In Press.

Variation in flooding-induced morphological traits in natural populations of white clover (Trifolium repens) and their effects on plant performance during soil flooding

PubMed Central

Huber, Heidrun; Jacobs, Elke; Visser, Eric J. W.

2009-01-01

Background and Aims Soil flooding leads to low soil oxygen concentrations and thereby negatively affects plant growth. Differences in flooding tolerance have been explained by the variation among species in the extent to which traits related to acclimation were expressed. However, our knowledge of variation within natural species (i.e. among individual genotypes) in traits related to flooding tolerance is very limited. Such data could tell us on which traits selection might have taken place, and will take place in future. The aim of the present study was to show that variation in flooding-tolerance-related traits is present among genotypes of the same species, and that both the constitutive variation and the plastic variation in flooding-induced changes in trait expression affect the performance of genotypes during soil flooding. Methods Clones of Trifolium repens originating from a river foreland were subjected to either drained, control conditions or to soil flooding. Constitutive expression of morphological traits was recorded on control plants, and flooding-induced changes in expression were compared with these constitutive expression levels. Moreover, the effect of both constitutive and flooding-induced trait expression on plant performance was determined. Key Results Constitutive and plastic variation of several morphological traits significantly affected plant performance. Even relatively small increases in root porosity and petiole length contributed to better performance during soil flooding. High specific leaf area, by contrast, was negatively correlated with performance during flooding. Conclusions The data show that different genotypes responded differently to soil flooding, which could be linked to variation in morphological trait expression. As flooded and drained conditions exerted different selection pressures on trait expression, the optimal value for constitutive and plastic traits will depend on the frequency and duration of flooding. These data will help us understanding the mechanisms affecting short- and long-term dynamics in flooding-prone ecosystems. PMID:18713824

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

NASA Astrophysics Data System (ADS)

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 be developed based on the identified hazard zones and geomorphic processes of macrochannel systems.

Robust flood area detection using a L-band synthetic aperture radar: Preliminary application for Florida, the U.S. affected by Hurricane Irma

NASA Astrophysics Data System (ADS)

Nagai, H.; Ohki, M.; Abe, T.

2017-12-01

Urgent crisis response for a hurricane-induced flood needs urgent providing of a flood map covering a broad region. However, there is no standard threshold values for automatic flood identification from pre-and-post images obtained by satellite-based synthetic aperture radars (SARs). This problem could hamper prompt data providing for operational uses. Furthermore, one pre-flood SAR image does not always represent potential water surfaces and river flows especially in tropical flat lands which are greatly influenced by seasonal precipitation cycle. We are, therefore, developing a new method of flood mapping using PALSAR-2, an L-band SAR, which is less affected by temporal surface changes. Specifically, a mean-value image and a standard-deviation image are calculated from a series of pre-flood SAR images. It is combined with a post-flood SAR image to obtain normalized backscatter amplitude difference (NoBADi), with which a difference between a post-flood image and a mean-value image is divided by a standard-deviation image to emphasize anomalous water extents. Flooding areas are then automatically obtained from the NoBADi images as lower-value pixels avoiding potential water surfaces. We applied this method to PALSAR-2 images acquired on Sept. 8, 10, and 12, 2017, covering flooding areas in a central region of Dominican Republic and west Florida, the U.S. affected by Hurricane Irma. The output flooding outlines are validated with flooding areas manually delineated from high-resolution optical satellite images, resulting in higher consistency and less uncertainty than previous methods (i.e., a simple pre-and-post flood difference and pre-and-post coherence changes). The NoBADi method has a great potential to obtain a reliable flood map for future flood hazards, not hampered by cloud cover, seasonal surface changes, and "casual" thresholds in the flood identification process.

Implementing the EU Floods Directive (2007/60/EC) in Austria: Flood Risk Management Plans

NASA Astrophysics Data System (ADS)

Neuhold, Clemens

2013-04-01

he Directive 2007/60/EC of the European Parliament and of the Council of 23 October 2007 on the assessment and management of flood risks (EFD) aims at the reduction of the adverse consequences for human health, the environment, cultural heritage and economic activity associated with floods in the Community. This task is to be achieved based on three process steps (1) preliminary flood risk assessment (finalised by the end of 2011), (2) flood hazard maps and flood risk maps (due 2013) and (3) flood risk management plans (due 2015). Currently, an interdisciplinary national working group is defining the methodological framework for flood risk management plans in Austria supported by a constant exchange with international bodies and experts. Referring to the EFD the components of the flood risk management plan are (excerpt): 1. conclusions of the preliminary flood risk assessment 2. flood hazard maps and flood risk maps and the conclusions that can be drawn from those maps 3. a description of the appropriate objectives of flood risk management 4. a summary of measures and their prioritisation aiming to achieve the appropriate objectives of flood risk management The poster refers to some of the major challenges in this process, such as the legal provisions, coordination of administrative units, definition of public relations, etc. The implementation of the EFD requires the harmonisation of legal instruments of various disciplines (e.g. water management, spatial planning, civil protection) enabling a coordinated - and ideally binding - practice of flood risk management. This process is highly influenced by the administrative organisation in Austria - federal, provincial and municipality level. The Austrian approach meets this organisational framework by structuring the development of the flood risk management plan into 3 time-steps: (a) federal blueprint, (b) provincial editing and (c) federal finishing as well as reporting to the European Commission. Each time-step addresses different administrative levels and spatial scales accompanied by the active involvement of interested parties.

Flood protection diversification to reduce probabilities of extreme losses.

PubMed

Zhou, Qian; Lambert, James H; Karvetski, Christopher W; Keisler, Jeffrey M; Linkov, Igor

2012-11-01

Recent catastrophic losses because of floods require developing resilient approaches to flood risk protection. This article assesses how diversification of a system of coastal protections might decrease the probabilities of extreme flood losses. The study compares the performance of portfolios each consisting of four types of flood protection assets in a large region of dike rings. A parametric analysis suggests conditions in which diversifications of the types of included flood protection assets decrease extreme flood losses. Increased return periods of extreme losses are associated with portfolios where the asset types have low correlations of economic risk. The effort highlights the importance of understanding correlations across asset types in planning for large-scale flood protection. It allows explicit integration of climate change scenarios in developing flood mitigation strategy. © 2012 Society for Risk Analysis.

Probabilistic mapping of flood-induced backscatter changes in SAR time series

NASA Astrophysics Data System (ADS)

Schlaffer, Stefan; Chini, Marco; Giustarini, Laura; Matgen, Patrick

2017-04-01

The information content of flood extent maps can be increased considerably by including information on the uncertainty of the flood area delineation. This additional information can be of benefit in flood forecasting and monitoring. Furthermore, flood probability maps can be converted to binary maps showing flooded and non-flooded areas by applying a threshold probability value pF = 0.5. In this study, a probabilistic change detection approach for flood mapping based on synthetic aperture radar (SAR) time series is proposed. For this purpose, conditional probability density functions (PDFs) for land and open water surfaces were estimated from ENVISAT ASAR Wide Swath (WS) time series containing >600 images using a reference mask of permanent water bodies. A pixel-wise harmonic model was used to account for seasonality in backscatter from land areas caused by soil moisture and vegetation dynamics. The approach was evaluated for a large-scale flood event along the River Severn, United Kingdom. The retrieved flood probability maps were compared to a reference flood mask derived from high-resolution aerial imagery by means of reliability diagrams. The obtained performance measures indicate both high reliability and confidence although there was a slight under-estimation of the flood extent, which may in part be attributed to topographically induced radar shadows along the edges of the floodplain. Furthermore, the results highlight the importance of local incidence angle for the separability between flooded and non-flooded areas as specular reflection properties of open water surfaces increase with a more oblique viewing geometry.

The Emergence of Flood Insurance in Canada: Navigating Institutional Uncertainty.

PubMed

Thistlethwaite, Jason

2017-04-01

Flood insurance has remained unavailable in Canada based on an assessment that it lacks economic viability. In response to Canada's costliest flood event to date in 2013, the Canadian insurance industry has started to develop a framework to expand existing property insurance to cover flood damage. Research on flood insurance has overlooked why and how insurance systems transition to expand insurance coverage without evidence of economic viability. This article will address this gap through a case study on the emergence of flood insurance in Canada, and the approach to its expansion. Between 2013 and 2016, insurance industry officials representing over 60% of premiums collected in Canada were interviewed. These interviews revealed that flood insurance is being expanded in response to institutional pressure, specifically external stakeholder expectations that the insurance industry will adopt a stronger role in managing flood risk through coverage of flood damage. Further evidence of this finding is explored by assessing the emergence of a unique flood insurance model that involves a risk-adjusted and optional product along with an expansion of government policy supporting flood risk mitigation. This approach attempts to balance industry concerns about economic viability with institutional pressure to reduce flood risk through insurance. This analysis builds on existing research by providing the first scholarly analysis of flood insurance in Canada, important "empirical" teeth to existing conceptual analysis on the availability of flood insurance, and the influence of institutional factors on risk analysis within the insurance sector. © 2016 Society for Risk Analysis.

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

NASA Astrophysics Data System (ADS)

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.

Modeling flood reduction effects of low impact development at a watershed scale.

PubMed

Ahiablame, Laurent; Shakya, Ranish

2016-04-15

Low impact development (LID) is a land development approach that seeks to mimic a site's pre-development hydrology. This study is a case study that assessed flood reduction capabilities of large-scale adoption of LID practices in an urban watershed in central Illinois using the Personal Computer Storm Water Management Model (PCSWMM). Two flood metrics based on runoff discharge were developed to determine action flood (43 m(3)/s) and major flood (95 m(3)/s). Four land use scenarios for urban growth were evaluated to determine the impacts of urbanization on runoff and flooding. Flood attenuation effects of porous pavement, rain barrel, and rain garden at various application levels were also evaluated as retrofitting technologies in the study watershed over a period of 30 years. Simulation results indicated that increase in urban land use from 50 to 94% between 1992 and 2030 increased average annual runoff and flood events by more than 30%, suggesting that urbanization without sound management would increase flood risks. The various implementation levels of the three LID practices resulted in 3-47% runoff reduction in the study watershed. Flood flow events that include action floods and major floods were also reduced by 0-40%, indicating that LID practices can be used to mitigate flood risk in urban watersheds. The study provides an insight into flood management with LID practices in existing urban areas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Flood Discharge Analysis with Nakayasu Method Using Combination of HEC-RAS Method on Deli River in Medan City

NASA Astrophysics Data System (ADS)

Harahap, Rumilla; Jeumpa, Kemala; Hadibroto, Bambang

2018-03-01

The problem in this research is how in the rainy season the water does not overflow, does not occur flood and during the dry season does not occur drought so it can adjust the condition or existence of Deli river which is around Medan city. Deli River floods often occur, either caused by a smaller capacity than the existing discharge, lack of maintenance and drainage and disposal systems that do not fit with the environment, resulting in flood subscriptions every year. The purpose of this research is to know flood discharge at Deli river as Flood control in Medan city. This research is analyzed on several methods such as log Pearson, Gumbel and hydrograph unit, while HEC-RAS method is modeling conducted in analyzing the water profile of the Deli River. Furthermore, the calculation of the periodic flood discharge using the Nakayasu Method. Calculation result at Deli River return period flood discharge 2 years with an area of 14.8 km2 annual flood hydrograph the total is 26.79 m3/sec on the hours at the 4th time. Return period flood discharge 5 years with an area of 14.8 km2 annual flood hydrograph the total is 73,44 m3/sec. While 25 annual return period total flood hydrograph is 146.50 m3/sec. With flood analysis can reduce and minimize the risk of losses and land can be mapped if in the area there is flooding.

Analysis of the linkage between rain and flood regime and its application to regional flood frequency estimation

NASA Astrophysics Data System (ADS)

Cunderlik, Juraj M.; Burn, Donald H.

2002-04-01

Improving techniques of flood frequency estimation at ungauged sites is one of the foremost goals of contemporary hydrology. River flood regime is a resultant reflection of a composite catchment hydrologic response to flood producing processes. In this sense the process of identifying homogeneous pooling groups can be plausibly based on catchment similarity in flood regime. Unfortunately the application of any pooling approach that is based on flood regime is restricted to gauged sites. Because flood regime can be markedly determined by rainfall regime, catchment similarity in rainfall regime can be an alternative option for identifying flood frequency pooling groups. An advantage of such a pooling approach is that rainfall data are usually spatially and temporary more abundant than flood data and the approach can also be applied at ungauged sites. Therefore in this study we have quantified the linkage between rainfall and flood regime and explored the appropriateness of substituting rainfall regime for flood regime in regional pooling schemes. Two different approaches to describing rainfall regime similarity using tools of directional statistics have been tested and used for evaluation of the potential of rainfall regime for identification of hydrologically homogeneous pooling groups. The outputs were compared to an existing pooling framework adopted in the Flood Estimation Handbook. The results demonstrate that regional pooling based on rainfall regime information leads to a high number of initially homogeneous groups and seems to be a sound pooling alternative for catchments with a close linkage between rain and flood regimes.

Socio-economic Impact Analysis for Near Real-Time Flood Detection in the Lower Mekong River Basin

NASA Astrophysics Data System (ADS)

Oddo, P.; Ahamed, A.; Bolten, J. D.

2017-12-01

Flood events pose a severe threat to communities in the Lower Mekong River Basin. The combination of population growth, urbanization, and economic development exacerbate the impacts of these flood events. Flood damage assessments are frequently used to quantify the economic losses in the wake of storms. These assessments are critical for understanding the effects of flooding on the local population, and for informing decision-makers about future risks. Remote sensing systems provide a valuable tool for monitoring flood conditions and assessing their severity more rapidly than traditional post-event evaluations. The frequency and severity of extreme flood events are projected to increase, further illustrating the need for improved flood monitoring and impact analysis. In this study we implement a socio-economic damage model into a decision support tool with near real-time flood detection capabilities (NASA's Project Mekong). Surface water extent for current and historical floods is found using multispectral Moderate-resolution Imaging Spectroradiometer (MODIS) 250-meter imagery and the spectral Normalized Difference Vegetation Index (NDVI) signatures of permanent water bodies (MOD44W). Direct and indirect damages to populations, infrastructure, and agriculture are assessed using the 2011 Southeast Asian flood as a case study. Improved land cover and flood depth assessments result in a more refined understanding of losses throughout the Mekong River Basin. Results suggest that rapid initial estimates of flood impacts can provide valuable information to governments, international agencies, and disaster responders in the wake of extreme flood events.

Mapping flood hazards under uncertainty through probabilistic flood inundation maps

NASA Astrophysics Data System (ADS)

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

2017-12-01

Changing precipitation, rapid urbanization, and population growth interact to create unprecedented challenges for flood mitigation and management. Standard methods for estimating risk from flood inundation maps generally involve simulations of floodplain hydraulics for an established regulatory discharge of specified frequency. Hydraulic model results are then geospatially mapped and depicted as a discrete boundary of flood extents and a binary representation of the probability of inundation (in or out) that is assumed constant over a project's lifetime. Consequently, existing methods utilized to define flood hazards and assess risk management are hindered by deterministic approaches that assume stationarity in a nonstationary world, failing to account for spatio-temporal variability of climate and land use as they translate to hydraulic models. This presentation outlines novel techniques for portraying flood hazards and the results of multiple flood inundation maps spanning hydroclimatic regions. Flood inundation maps generated through modeling of floodplain hydraulics are probabilistic reflecting uncertainty quantified through Monte-Carlo analyses of model inputs and parameters under current and future scenarios. The likelihood of inundation and range of variability in flood extents resulting from Monte-Carlo simulations are then compared with deterministic evaluations of flood hazards from current regulatory flood hazard maps. By facilitating alternative approaches of portraying flood hazards, the novel techniques described in this presentation can contribute to a shifting paradigm in flood management that acknowledges the inherent uncertainty in model estimates and the nonstationary behavior of land use and climate.

Understanding high magnitude flood risk: evidence from the past

NASA Astrophysics Data System (ADS)

MacDonald, N.

2009-04-01

The average length of gauged river flow records in the UK is ~25 years, which presents a problem in determining flood risk for high-magnitude flood events. Severe floods have been recorded in many UK catchments during the past 10 years, increasing the uncertainty in conventional flood risk estimates based on river flow records. Current uncertainty in flood risk has implications for society (insurance costs), individuals (personal vulnerability) and water resource managers (flood/drought risk). An alternative approach is required which can improve current understanding of the flood frequency/magnitude relationship. Historical documentary accounts are now recognised as a valuable resource when considering the flood frequency/magnitude relationship, but little consideration has been given to the temporal and spatial distribution of these records. Building on previous research based on British rivers (urban centre): Ouse (York), Trent (Nottingham), Tay (Perth), Severn (Shrewsbury), Dee (Chester), Great Ouse (Cambridge), Sussex Ouse (Lewes), Thames (Oxford), Tweed (Kelso) and Tyne (Hexham), this work considers the spatial and temporal distribution of historical flooding. The selected sites provide a network covering many of the largest river catchments in Britain, based on urban centres with long detailed documentary flood histories. The chronologies offer an opportunity to assess long-term patterns of flooding, indirectly determining periods of climatic variability and potentially increased geomorphic activity. This research represents the first coherent large scale analysis undertaken of historical multi-catchment flood chronologies, providing an unparalleled network of sites, permitting analysis of the spatial and temporal distribution of historical flood patterns on a national scale.

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

NASA Astrophysics Data System (ADS)

Merz, B.; Aerts, J.; Arnbjerg-Nielsen, K.; Baldi, M.; Becker, A.; Bichet, A.; Blöschl, G.; Bouwer, L. M.; Brauer, A.; Cioffi, F.; Delgado, J. M.; Gocht, M.; Guzzetti, F.; Harrigan, S.; Hirschboeck, K.; Kilsby, C.; Kron, W.; Kwon, H.-H.; Lall, U.; Merz, R.; Nissen, K.; Salvatti, P.; Swierczynski, T.; Ulbrich, U.; Viglione, A.; Ward, P. J.; Weiler, M.; Wilhelm, B.; Nied, M.

2014-07-01

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 of local, catchment-specific characteristics, such as meteorology, topography and geology. These traditional views have been beneficial, but they have a narrow framing. In this paper we contrast traditional views with broader perspectives that are emerging from an improved understanding of the climatic 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 approaches in flood estimation need to be complemented by the search for the causal mechanisms and dominant processes in the atmosphere, catchment and river system that leave their fingerprints on flood characteristics. (3) Natural climate variability leads to time-varying flood characteristics, 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 the interactions between society and floods. (5) Given the global scale and societal importance, we call for the organization of an international multidisciplinary collaboration and data-sharing initiative to further understand the links between climate and flooding and to advance flood research.

78 FR 14584 - Proposed Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-06

...; Internal Agency Docket No. FEMA-B-1296] Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard..., Special Flood Hazard Area (SFHA) boundary or zone designation, or regulatory floodway on the Flood...

A new automatic SAR-based flood mapping application hosted on the European Space Agency's grid processing on demand fast access to imagery environment

NASA Astrophysics Data System (ADS)

Hostache, Renaud; Chini, Marco; Matgen, Patrick; Giustarini, Laura

2013-04-01

There is a clear need for developing innovative processing chains based on earth observation (EO) data to generate products supporting emergency response and flood management at a global scale. Here an automatic flood mapping application is introduced. The latter is currently hosted on the Grid Processing on Demand (G-POD) Fast Access to Imagery (Faire) environment of the European Space Agency. The main objective of the online application is to deliver flooded areas using both recent and historical acquisitions of SAR data in an operational framework. It is worth mentioning that the method can be applied to both medium and high resolution SAR images. The flood mapping application consists of two main blocks: 1) A set of query tools for selecting the "crisis image" and the optimal corresponding pre-flood "reference image" from the G-POD archive. 2) An algorithm for extracting flooded areas using the previously selected "crisis image" and "reference image". The proposed method is a hybrid methodology, which combines histogram thresholding, region growing and change detection as an approach enabling the automatic, objective and reliable flood extent extraction from SAR images. The method is based on the calibration of a statistical distribution of "open water" backscatter values inferred from SAR images of floods. Change detection with respect to a pre-flood reference image helps reducing over-detection of inundated areas. The algorithms are computationally efficient and operate with minimum data requirements, considering as input data a flood image and a reference image. Stakeholders in flood management and service providers are able to log onto the flood mapping application to get support for the retrieval, from the rolling archive, of the most appropriate pre-flood reference image. Potential users will also be able to apply the implemented flood delineation algorithm. Case studies of several recent high magnitude flooding events (e.g. July 2007 Severn River flood, UK and March 2010 Red River flood, US) observed by high-resolution SAR sensors as well as airborne photography highlight advantages and limitations of the online application. A mid-term target is the exploitation of ESA SENTINEL 1 SAR data streams. In the long term it is foreseen to develop a potential extension of the application for systematically extracting flooded areas from all SAR images acquired on a daily, weekly or monthly basis. On-going research activities investigate the usefulness of the method for mapping flood hazard at global scale using databases of historic SAR remote sensing-derived flood inundation maps.

Proteomic and metabolomic analyses of soybean root tips under flooding stress.

PubMed

Komatsu, Setsuko; Nakamura, Takuji; Sugimoto, Yurie; Sakamoto, Kazunori

2014-01-01

Flooding is one of the serious problems for soybean plants because it inhibits growth. Proteomic and metabolomic techniques were used to determine whether proteins and metabolites are altered in the root tips of soybeans under flooding stress. Two-day-old soybean plants were flooded for 2 days, and proteins and metabolites were extracted from root tips. Flooding-responsive proteins were identified using two-dimensional- or SDS-polyacrylamide gel electrophoresis- based proteomics techniques. Using both techniques, 172 proteins increased and 105 proteins decreased in abundance in the root tips of flood-stressed soybean. The abundance of methionine synthase, heat shock cognate protein, urease, and phosphoenol pyruvate carboxylase was significantly increased by flooding stress. Furthermore, 73 flooding-responsive metabolites were identified using capillary electrophoresis-mass spectrometry. The levels of gamma-aminobutyric acid, glycine, NADH2, and phosphoenol pyruvate were increased by flooding stress. Taken together, these results suggest that synthesis of phosphoenol pyruvate by way of oxaloacetate produced in the tricarboxylic acid cycle is activated in soybean root tips in response to flooding stress, and that flooding stress also leads to modulation of the urea cycle in the root tips.

Quantification of increased flood risk due to global climate change for urban river management planning.

PubMed

Morita, M

2011-01-01

Global climate change is expected to affect future rainfall patterns. These changes should be taken into account when assessing future flooding risks. This study presents a method for quantifying the increase in flood risk caused by global climate change for use in urban flood risk management. Flood risk in this context is defined as the product of flood damage potential and the probability of its occurrence. The study uses a geographic information system-based flood damage prediction model to calculate the flood damage caused by design storms with different return periods. Estimation of the monetary damages these storms produce and their return periods are precursors to flood risk calculations. The design storms are developed from modified intensity-duration-frequency relationships generated by simulations of global climate change scenarios (e.g. CGCM2A2). The risk assessment method is applied to the Kanda River basin in Tokyo, Japan. The assessment provides insights not only into the flood risk cost increase due to global warming, and the impact that increase may have on flood control infrastructure planning.

Repetitive flood victims and acceptance of FEMA mitigation offers: an analysis with community-system policy implications.

PubMed

Kick, Edward L; Fraser, James C; Fulkerson, Gregory M; McKinney, Laura A; De Vries, Daniel H

2011-07-01

Of all natural disasters, flooding causes the greatest amount of economic and social damage. The United States' Federal Emergency Management Agency (FEMA) uses a number of hazard mitigation grant programmes for flood victims, including mitigation offers to relocate permanently repetitive flood loss victims. This study examines factors that help to explain the degree of difficulty repetitive flood loss victims experience when they make decisions about relocating permanently after multiple flood losses. Data are drawn from interviews with FEMA officials and a survey of flood victims from eight repetitive flooding sites. The qualitative and quantitative results show the importance of rational choices by flood victims in their mitigation decisions, as they relate to financial variables, perceptions of future risk, attachments to home and community, and the relationships between repetitive flood loss victims and the local flood management officials who help them. The results offer evidence to suggest the value of a more community-system approach to FEMA relocation practices. © 2011 The Author(s). Disasters © Overseas Development Institute, 2011.

Demand analysis of flood insurance by using logistic regression model and genetic algorithm

NASA Astrophysics Data System (ADS)

Sidi, P.; Mamat, M. B.; Sukono; Supian, S.; Putra, A. S.

2018-03-01

Citarum River floods in the area of South Bandung Indonesia, often resulting damage to some buildings belonging to the people living in the vicinity. One effort to alleviate the risk of building damage is to have flood insurance. The main obstacle is not all people in the Citarum basin decide to buy flood insurance. In this paper, we intend to analyse the decision to buy flood insurance. It is assumed that there are eight variables that influence the decision of purchasing flood assurance, include: income level, education level, house distance with river, building election with road, flood frequency experience, flood prediction, perception on insurance company, and perception towards government effort in handling flood. The analysis was done by using logistic regression model, and to estimate model parameters, it is done with genetic algorithm. The results of the analysis shows that eight variables analysed significantly influence the demand of flood insurance. These results are expected to be considered for insurance companies, to influence the decision of the community to be willing to buy flood insurance.

Risk-trading in flood management: An economic model.

PubMed

Chang, Chiung Ting

2017-09-15

Although flood management is no longer exclusively a topic of engineering, flood mitigation continues to be associated with hard engineering options. Flood adaptation or the capacity to adapt to flood risk, as well as a demand for internalizing externalities caused by flood risk between regions, complicate flood management activities. Even though integrated river basin management has long been recommended to resolve the above issues, it has proven difficult to apply widely, and sometimes even to bring into existence. This article explores how internalization of externalities as well as the realization of integrated river basin management can be encouraged via the use of a market-based approach, namely a flood risk trading program. In addition to maintaining efficiency of optimal resource allocation, a flood risk trading program may also provide a more equitable distribution of benefits by facilitating decentralization. This article employs a graphical analysis to show how flood risk trading can be implemented to encourage mitigation measures that increase infiltration and storage capacity. A theoretical model is presented to demonstrate the economic conditions necessary for flood risk trading. Copyright © 2017 Elsevier Ltd. All rights reserved.

Flood Risk and Probabilistic Benefit Assessment to Support Management of Flood-Prone Lands: Evidence From Candaba Floodplains, Philippines

NASA Astrophysics Data System (ADS)

Juarez, A. M.; Kibler, K. M.; Sayama, T.; Ohara, M.

2016-12-01

Flood management decision-making is often supported by risk assessment, which may overlook the role of coping capacity and the potential benefits derived from direct use of flood-prone land. Alternatively, risk-benefit analysis can support floodplain management to yield maximum socio-ecological benefits for the minimum flood risk. We evaluate flood risk-probabilistic benefit tradeoffs of livelihood practices compatible with direct human use of flood-prone land (agriculture/wild fisheries) and nature conservation (wild fisheries only) in Candaba, Philippines. Located north-west to Metro Manila, Candaba area is a multi-functional landscape that provides a temporally-variable mix of possible land uses, benefits and ecosystem services of local and regional value. To characterize inundation from 1.3- to 100-year recurrence intervals we couple frequency analysis with rainfall-runoff-inundation modelling and remotely-sensed data. By combining simulated probabilistic floods with both damage and benefit functions (e.g. fish capture and rice yield with flood intensity) we estimate potential damages and benefits over varying probabilistic flood hazards. We find that although direct human uses of flood-prone land are associated with damages, for all the investigated magnitudes of flood events with different frequencies, the probabilistic benefits ( 91 million) exceed risks by a large margin ( 33 million). Even considering risk, probabilistic livelihood benefits of direct human uses far exceed benefits provided by scenarios that exclude direct "risky" human uses (difference of 85 million). In addition, we find that individual coping strategies, such as adapting crop planting periods to the flood pulse or fishing rather than cultivating rice in the wet season, minimize flood losses ( 6 million) while allowing for valuable livelihood benefits ($ 125 million) in flood-prone land. Analysis of societal benefits and local capacities to cope with regular floods demonstrate the relevance of accounting for the full range of flood events and their relation to both potential damages and benefits in risk assessments. Management measures may thus be designed to reflect local contexts and support benefits of natural hydrologic processes, while minimizing flood damage.

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

USGS Publications Warehouse

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 maps of the 100-year and 500-year flood plains and the 100-year floodway for each tributary and the main stem of Blackberry Creek were compiled.

Estimating Paleoflood Magnitude From Tree-Ring Anatomy and the Height of Abrasion Scars

NASA Astrophysics Data System (ADS)

Yanosky, T. M.; Jarrett, R. D.

2003-12-01

Evidence of floods preserved in the growth rings of trees can be used to extend the historical record of flooding or to estimate the magnitude of extraordinary floods on ungaged streams. Floods that damage the aerial parts of trees during the growing season sometimes induce striking anatomical changes in subsequent growth of rings in the lower trunk. In ring-porous species, this growth most commonly produces concentric bands of atypically large vessels within the latewood. The number and diameter of anomalous vessels seem positively related to the amount of flood damage, and thus can be used to refine estimates of flood magnitude when also considering the position of the tree relative to the channel and its approximate height during the flood. Floods of long duration on low-gradient streams are less likely to damage trees directly, but prolonged root flooding often results in the formation of narrow rings with atypically small vessels; shorter-duration floods, sometimes inundating roots for as little as several days, are followed by the production of fibers (non-conducting cells) with large lumens and thin walls that appear as light-colored bands compared to earlier-formed tissue. In these instances, a series of trees increasingly distant from the channel can be used to estimate a minimum flood elevation. Abrasion scars from flood-borne debris often are the most easily observed evidence of flood damage and, like anatomical abnormalities, can be precisely dated. The relation between the heights of scars and maximum flood stages depends in part upon channel slope. Previous studies have indicated that scar heights along low-gradient streams are the same or slightly lower than maximum flood elevations. Along the high-gradient (6% maximum slope) Buffalo Creek, Colorado USA, scar heights measured in 102 trees following a flood in 1996 ranged from -0.6 to +1.5 m relative to the actual crest elevation. Scar elevations exceeding flood elevations by 3-4 m, however, were observed following a flood in 2002 along a small Colorado stream with slopes ranging from 6 to 15%.

City-scale accessibility of emergency responders operating during flood events

NASA Astrophysics Data System (ADS)

Green, Daniel; Yu, Dapeng; Pattison, Ian; Wilby, Robert; Bosher, Lee; Patel, Ramila; Thompson, Philip; Trowell, Keith; Draycon, Julia; Halse, Martin; Yang, Lili; Ryley, Tim

2017-01-01

Emergency responders often have to operate and respond to emergency situations during dynamic weather conditions, including floods. This paper demonstrates a novel method using existing tools and datasets to evaluate emergency responder accessibility during flood events within the city of Leicester, UK. Accessibility was quantified using the 8 and 10 min legislative targets for emergency provision for the ambulance and fire and rescue services respectively under "normal" no-flood conditions, as well as flood scenarios of various magnitudes (1 in 20-year, 1 in 100-year and 1 in 1000-year recurrence intervals), with both surface water and fluvial flood conditions considered. Flood restrictions were processed based on previous hydrodynamic inundation modelling undertaken and inputted into a Network Analysis framework as restrictions for surface water and fluvial flood events. Surface water flooding was shown to cause more disruption to emergency responders operating within the city due to its widespread and spatially distributed footprint when compared to fluvial flood events of comparable magnitude. Fire and rescue 10 min accessibility was shown to decrease from 100, 66.5, 39.8 and 26.2 % under the no-flood, 1 in 20-year, 1 in 100-year and 1 in 1000-year surface water flood scenarios respectively. Furthermore, total inaccessibility was shown to increase with flood magnitude from 6.0 % under the 1 in 20-year scenario to 31.0 % under the 1 in 100-year flood scenario. Additionally, the evolution of emergency service accessibility throughout a surface water flood event is outlined, demonstrating the rapid impact on emergency service accessibility within the first 15 min of the surface water flood event, with a reduction in service coverage and overlap being observed for the ambulance service during a 1 in 100-year flood event. The study provides evidence to guide strategic planning for decision makers prior to and during emergency response to flood events at the city scale. It also provides a readily transferable method for exploring the impacts of natural hazards or disruptions in other cities or regions based on historic, scenario-based events or real-time forecasting, if such data are available.

Dynamic Flood Vulnerability Mapping with Google Earth Engine

NASA Astrophysics Data System (ADS)

Tellman, B.; Kuhn, C.; Max, S. A.; Sullivan, J.

2015-12-01

Satellites capture the rate and character of environmental change from local to global levels, yet integrating these changes into flood exposure models can be cost or time prohibitive. We explore an approach to global flood modeling by leveraging satellite data with computing power in Google Earth Engine to dynamically map flood hazards. Our research harnesses satellite imagery in two main ways: first to generate a globally consistent flood inundation layer and second to dynamically model flood vulnerability. Accurate and relevant hazard maps rely on high quality observation data. Advances in publicly available spatial, spectral, and radar data together with cloud computing allow us to improve existing efforts to develop a comprehensive flood extent database to support model training and calibration. This talk will demonstrate the classification results of algorithms developed in Earth Engine designed to detect flood events by combining observations from MODIS, Landsat 8, and Sentinel-1. Our method to derive flood footprints increases the number, resolution, and precision of spatial observations for flood events both in the US, recorded in the NCDC (National Climatic Data Center) storm events database, and globally, as recorded events from the Colorado Flood Observatory database. This improved dataset can then be used to train machine learning models that relate spatial temporal flood observations to satellite derived spatial temporal predictor variables such as precipitation, antecedent soil moisture, and impervious surface. This modeling approach allows us to rapidly update models with each new flood observation, providing near real time vulnerability maps. We will share the water detection algorithms used with each satellite and discuss flood detection results with examples from Bihar, India and the state of New York. We will also demonstrate how these flood observations are used to train machine learning models and estimate flood exposure. The final stage of our comprehensive approach to flood vulnerability couples inundation extent with social data to determine which flood exposed communities have the greatest propensity for loss. Specifically, by linking model outputs to census derived social vulnerability estimates (Indian and US, respectively) to predict how many people are at risk.

The impact of flood variables on riparian vegetation

NASA Astrophysics Data System (ADS)

Dzubakova, Katarina; Molnar, Peter

2016-04-01

The riparian vegetation of Alpine rivers often grows in temporally dynamic riverine environments which are characterized by pronounced meteorological and hydrological fluctuations and high resource competition. Within these relatively rough conditions, riparian vegetation fulfils essential ecosystem functions such as water retention, biomass production and habitat to endangered species. The identification of relevant flood attributes impacting riparian vegetation is crucial for a better understanding of the vegetation dynamics in the riverine ecosystem. Hence, in this contribution we aim to quantify the ecological effects of flood attributes on riparian vegetation and to analyze the spatial coherence of flood-vegetation interaction patterns. We analyzed a 500 m long and 300-400 m wide study reach located on the Maggia River in southern Switzerland. Altogether five floods between 2008 and 2011 with return periods ranging from 1.4 to 20.1 years were studied. To assess the significance of the flood attributes, we compared post-flood to pre-flood vegetation vigour to flood intensity. Pre- and post-flood vegetation vigour was represented by the Normalized Difference Vegetation Index (NDVI) which was computed from images recorded by high resolution ground-based cameras. Flood intensity was expressed in space in the study reach by six flood attributes (inundation duration, maximum depth, maximum and total velocity, maximum and total shear stress) which were simulated by the 2D hydrodynamic model BASEMENT (VAW, ETH Zurich). We considered three floodplain units separately (main bar, secondary bar, transitional zone). Based on our results, pre-flood vegetation vigour largely determined vegetation reaction to the less intense floods (R = 0.59-0.96). However for larger floods with a strong erosive effect, its contribution was significantly lower (R = 0.59-0.68). Using multivariate regression analysis we show that pre-flood vegetation vigour and maximum velocity proved to be the most significant variables impacting vegetation response. Generally, maximal flood attributes had more significant impacts than integrated attributes over the flood duration. Additional explanatory variables in the model should account for vegetation heterogeneity, groundwater conditions and different effects of lateral and surface erosion.

Flood triggering in Switzerland: the role of daily to monthly preceding precipitation

NASA Astrophysics Data System (ADS)

Froidevaux, P.; Schwanbeck, J.; Weingartner, R.; Chevalier, C.; Martius, O.

2015-09-01

Determining the role of different precipitation periods for peak discharge generation is crucial for both projecting future changes in flood probability and for short- and medium-range flood forecasting. In this study, catchment-averaged daily precipitation time series are analyzed prior to annual peak discharge events (floods) in Switzerland. The high number of floods considered - more than 4000 events from 101 catchments have been analyzed - allows to derive significant information about the role of antecedent precipitation for peak discharge generation. Based on the analysis of precipitation times series, a new separation of flood-related precipitation periods is proposed: (i) the period 0 to 1 day before flood days, when the maximum flood-triggering precipitation rates are generally observed, (ii) the period 2 to 3 days before flood days, when longer-lasting synoptic situations generate "significantly higher than normal" precipitation amounts, and (iii) the period from 4 days to 1 month before flood days when previous wet episodes may have already preconditioned the catchment. The novelty of this study lies in the separation of antecedent precipitation into the precursor antecedent precipitation (4 days before floods or earlier, called PRE-AP) and the short range precipitation (0 to 3 days before floods, a period when precipitation is often driven by one persistent weather situation like e.g., a stationary low-pressure system). A precise separation of "antecedent" and "peak-triggering" precipitation is not attempted. Instead, the strict definition of antecedent precipitation periods permits a direct comparison of all catchments. The precipitation accumulating 0 to 3 days before an event is the most relevant for floods in Switzerland. PRE-AP precipitation has only a weak and region-specific influence on flood probability. Floods were significantly more frequent after wet PRE-AP periods only in the Jura Mountains, in the western and eastern Swiss plateau, and at the outlet of large lakes. As a general rule, wet PRE-AP periods enhance the flood probability in catchments with gentle topography, high infiltration rates, and large storage capacity (karstic cavities, deep soils, large reservoirs). In contrast, floods were significantly less frequent after wet PRE-AP periods in glacial catchments because of reduced melt. For the majority of catchments however, no significant correlation between precipitation amounts and flood occurrences is found when the last 3 days before floods are omitted in the precipitation amounts. Moreover, the PRE-AP was not higher for extreme floods than for annual floods with a high frequency and was very close to climatology for all floods. The fact that floods are not significantly more frequent nor more intense after wet PRE-AP is a clear indicator of a short discharge memory of Pre-Alpine, Alpine and South Alpine Swiss catchments. Our study poses the question whether the impact of long-term precursory precipitation for floods in such catchments is not overestimated in the general perception. The results suggest that the consideration of a 3-4 days precipitation period should be sufficient to represent (understand, reconstruct, model, project) Swiss Alpine floods.

Flood triggering in Switzerland: the role of daily to monthly preceding precipitation

NASA Astrophysics Data System (ADS)

Froidevaux, P.; Schwanbeck, J.; Weingartner, R.; Chevalier, C.; Martius, O.

2015-03-01

Determining the role of different precipitation periods for peak discharge generation is crucial for both projecting future changes in flood probability and for short- and medium-range flood forecasting. We analyze catchment-averaged daily precipitation time series prior to annual peak discharge events (floods) in Switzerland. The high amount of floods considered - more than 4000 events from 101 catchments have been analyzed - allows to derive significant information about the role of antecedent precipitation for peak discharge generation. Based on the analysis of precipitation times series, we propose a new separation of flood-related precipitation periods: (i) the period 0 to 1 day before flood days, when the maximum flood-triggering precipitation rates are generally observed, (ii) the period 2 to 3 days before flood days, when longer-lasting synoptic situations generate "significantly higher than normal" precipitation amounts, and (iii) the period from 4 days to one month before flood days when previous wet episodes may have already preconditioned the catchment. The novelty of this study lies in the separation of antecedent precipitation into the precursor antecedent precipitation (4 days before floods or earlier, called PRE-AP) and the short range precipitation (0 to 3 days before floods, a period when precipitation is often driven by one persistent weather situation like e.g. a stationary low-pressure system). Because we consider a high number of events and because we work with daily precipitation values, we do not separate the "antecedent" and "peak-triggering" precipitation. The whole precipitation recorded during the flood day is included in the short-range antecedent precipitation. The precipitation accumulating 0 to 3 days before an event is the most relevant for floods in Switzerland. PRE-AP precipitation has only a weak and region-specific influence on flood probability. Floods were significantly more frequent after wet PRE-AP periods only in the Jura Mountains, in the western and eastern Swiss plateau, and at the exit of large lakes. As a general rule, wet PRE-AP periods enhance the flood probability in catchments with gentle topography, high infiltration rates, and large storage capacity (karstic cavities, deep soils, large reservoirs). In contrast, floods were significantly less frequent after wet PRE-AP periods in glacial catchments because of reduced melt. For the majority of catchments however, no significant correlation between precipitation amounts and flood occurrences is found when the last three days before floods are omitted in the precipitation amounts. Moreover, the PRE-AP was not higher for extreme floods than for annual floods with a high frequency and was very close to climatology for all floods. The weak influence of PRE-AP is a clear indicator of a short discharge memory of Prealpine, Alpine and Southalpine Swiss catchments. Our study nevertheless poses the question whether the impact of long-term precursory precipitation for floods in such catchments is not overestimated in the general perception. We conclude that the consideration of a 3-4 days precipitation period should be sufficient to represent (understand, reconstruct, model, project) Swiss Alpine floods.

Potential flood hazard assessment by integration of ALOS PALSAR and ASTER GDEM: a case study for the Hoa Chau commune, Hoa Vang district, in central Vietnam

NASA Astrophysics Data System (ADS)

Huong, Do Thi Viet; Nagasawa, Ryota

2014-01-01

The potential flood hazard was assessed for the Hoa Chau commune in central Vietnam in order to identify the high flood hazard zones for the decision makers who will execute future rural planning. A new approach for deriving the potential flood hazard based on integration of inundation and flow direction maps is described. Areas inundated in the historical flood event of 2007 were extracted from Advanced Land Observing Satellite (ALOS) phased array L-band synthetic aperture data radar (PALSAR) images, while flow direction characteristics were derived from the ASTER GDEM to extract the depressed surfaces. Past flood experience and the flow direction were then integrated to analyze and rank the potential flood hazard zones. The land use/cover map extracted from LANDSAT TM and flood depth point records from field surveys were utilized to check the possibility of susceptible inundated areas, extracting data from ALOS PALSAR and ranking the potential flood hazard. The estimation of potential flood hazard areas revealed that 17.43% and 17.36% of Hoa Chau had high and medium potential flood hazards, respectively. The flow direction and ALOS PALSAR data were effectively integrated for determining the potential flood hazard when hydrological and meteorological data were inadequate and remote sensing images taken during flood times were not available or were insufficient.

Analysis of flood inundation in ungauged basins based on multi-source remote sensing data.

PubMed

Gao, Wei; Shen, Qiu; Zhou, Yuehua; Li, Xin

2018-02-09

Floods are among the most expensive natural hazards experienced in many places of the world and can result in heavy losses of life and economic damages. The objective of this study is to analyze flood inundation in ungauged basins by performing near-real-time detection with flood extent and depth based on multi-source remote sensing data. Via spatial distribution analysis of flood extent and depth in a time series, the inundation condition and the characteristics of flood disaster can be reflected. The results show that the multi-source remote sensing data can make up the lack of hydrological data in ungauged basins, which is helpful to reconstruct hydrological sequence; the combination of MODIS (moderate-resolution imaging spectroradiometer) surface reflectance productions and the DFO (Dartmouth Flood Observatory) flood database can achieve the macro-dynamic monitoring of the flood inundation in ungauged basins, and then the differential technique of high-resolution optical and microwave images before and after floods can be used to calculate flood extent to reflect spatial changes of inundation; the monitoring algorithm for the flood depth combining RS and GIS is simple and easy and can quickly calculate the depth with a known flood extent that is obtained from remote sensing images in ungauged basins. Relevant results can provide effective help for the disaster relief work performed by government departments.

Disastrous torrential floods in mountain areas in Serbia

NASA Astrophysics Data System (ADS)

Gavrilovic, Z.

2009-04-01

In Serbia, the relief is predominantly hilly and mountainous, intersected with numerous rivers. The greatest number of watercourses are small torrents; however the proportionally large rivers also have a distinctive torrential character. The highest parts of the catchments are at the altitudes above 1500 m, while their confluences are at the altitudes of 200 - 300 m. The catchment and channel slopes are extremely steep. So, as the initial natural preconditions are satisfied, torrential floods are the consequence. Although the Južna Morava catchments were regulated by erosion control works, during the last decades there were numerous torrential floods. Some of the floods had disastrous proportions, not recorded in Serbia or in Europe. The flood of river Vlasina in 1988 was presented to the professional public several times. This flood was not an isolated case. Many large-scale torrential floods occurred in Serbia from 1994 to 2007. As there were floods also in 2007, the causes of the recorded floods had to be analysed. The analysis pointed out a series of scenarios which were the causes of disastrous torrential floods, and also the disadvantages of the actual system of torrent and erosion control. Special attention was focused on the floods which resulted from sudden snow melting. This paper will present the results of the analyses of the extreme torrential floods of the rivers Nišava and Vlasina. Key words: Flood, torrents, torrent control, erosion control

Flooding Hazard Maps of Different Land Uses in Subsidence Area

NASA Astrophysics Data System (ADS)

Lin, Yongjun; Chang, Hsiangkuan; Tan, Yihchi

2017-04-01

This study aims on flooding hazard maps of different land uses in the subsidence area of southern Taiwan. Those areas are low-lying due to subsidence resulting from over pumping ground water for aquaculture. As a result, the flooding due to storm surges and extreme rainfall are frequent in this area and are expected more frequently in the future. The main land uses there include: residence, fruit trees, and aquaculture. The hazard maps of the three land uses are investigated. The factors affecting hazards of different land uses are listed below. As for residence, flooding depth, duration of flooding, and rising rate of water surface level are factors affecting its degree of hazard. High flooding depth, long duration of flooding, and fast rising rate of water surface make residents harder to evacuate. As for fruit trees, flooding depth and duration of flooding affects its hazard most due to the root hypoxia. As for aquaculture, flooding depth affects its hazard most because the high flooding depth may cause the fish flush out the fishing ponds. An overland flow model is used for simulations of hydraulic parameters for factors such as flooding depth, rising rate of water surface level and duration of flooding. As above-mentioned factors, the hazard maps of different land uses can be made and high hazardous are can also be delineated in the subsidence areas.

77 FR 55784 - Proposed Flood Elevation Determinations; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

... the flooding sources for Franklin County, North Carolina and Incorporated Areas. The flooding source... ``Franklin County, North Carolina, and Incorporated Areas'' addressed several flooding sources, including Taylors Creek. The proposed rule incorrectly listed the flooding source name as Taylors Branch instead of...

44 CFR 67.4 - Proposed flood elevation determination.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Proposed flood elevation..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program APPEALS FROM PROPOSED FLOOD ELEVATION DETERMINATIONS § 67.4 Proposed flood elevation determination. The Federal...

77 FR 18844 - Proposed Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-28

...: Internal Agency Docket No. FEMA-B-1236] Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood depth...

44 CFR 79.1 - Purpose.

Code of Federal Regulations, 2011 CFR

2011-10-01

... INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION GRANTS § 79.1 Purpose. (a... the hazard mitigation grant programs made available under the National Flood Insurance Act of 1968, as... Repetitive Loss (SRL) and Flood Mitigation Assistance (FMA) grant programs mitigate losses from floods...

44 CFR 79.1 - Purpose.

Code of Federal Regulations, 2014 CFR

2014-10-01

... INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION GRANTS § 79.1 Purpose. (a... the hazard mitigation grant programs made available under the National Flood Insurance Act of 1968, as... Repetitive Loss (SRL) and Flood Mitigation Assistance (FMA) grant programs mitigate losses from floods...

44 CFR 67.4 - Proposed flood elevation determination.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program APPEALS FROM PROPOSED FLOOD ELEVATION DETERMINATIONS § 67.4 Proposed flood elevation determination. The Federal... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Proposed flood elevation...

78 FR 43899 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-22

..., ``Flood Insurance.'') Dated: July 2, 2013. Roy E. Wright, Deputy Associate Administrator for Mitigation...] Changes in Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final notice. SUMMARY: New or modified Base (1% annual-chance) Flood Elevations (BFEs), base flood depths...

44 CFR 67.4 - Proposed flood elevation determination.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program APPEALS FROM PROPOSED FLOOD ELEVATION DETERMINATIONS § 67.4 Proposed flood elevation determination. The Federal... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Proposed flood elevation...

44 CFR 79.1 - Purpose.

Code of Federal Regulations, 2012 CFR

2012-10-01

... INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION GRANTS § 79.1 Purpose. (a... the hazard mitigation grant programs made available under the National Flood Insurance Act of 1968, as... Repetitive Loss (SRL) and Flood Mitigation Assistance (FMA) grant programs mitigate losses from floods...

78 FR 49277 - Proposed Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-13

...: Internal Agency Docket No. FEMA-B-1345] Proposed Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: Comments are requested on proposed flood hazard determinations, which may include additions or modifications of any Base Flood Elevation (BFE), base flood depth...

44 CFR 79.1 - Purpose.

Code of Federal Regulations, 2013 CFR

2013-10-01

... INSURANCE AND HAZARD MITIGATION National Flood Insurance Program FLOOD MITIGATION GRANTS § 79.1 Purpose. (a... the hazard mitigation grant programs made available under the National Flood Insurance Act of 1968, as... Repetitive Loss (SRL) and Flood Mitigation Assistance (FMA) grant programs mitigate losses from floods...

Response to Comments on "Outburst flood at 1920 BCE supports historicity of China's Great Flood and the Xia dynasty".

PubMed

Wu, Qinglong; Zhao, Zhijun; Liu, Li; Granger, Darryl E; Wang, Hui; Cohen, David J; Wu, Xiaohong; Ye, Maolin; Bar-Yosef, Ofer; Lu, Bin; Zhang, Jin; Zhang, Peizhen; Yuan, Daoyang; Qi, Wuyun; Cai, Linhai; Bai, Shibiao

2017-03-31

Wu et al , Han, and Huang et al question our reconstruction of a large outburst flood and its possible relationship to China's Great Flood and the Xia dynasty. Here, we clarify misconceptions concerning geologic evidence of the flood, its timing and magnitude, and the complex social-cultural response. We also further discuss how this flood may be related to ancient accounts of the Great Flood and origins of the Xia dynasty. Copyright © 2017, American Association for the Advancement of Science.

Hydrologic, Hydraulic, and Flood Analyses of the Blackberry Creek Watershed, Kendall County, Illinois

USGS Publications Warehouse

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

2007-01-01

Results of the hydrologic model, flood-frequency, hydraulic model, and flood-hazard analysis of the Blackberry Creek watershed in Kendall County, Illinois, indicate that the 100-year and 500-year flood plains cover approximately 3,699 and 3,762 acres of land, respectively. On the basis of land-cover data for 2003, most of the land in the flood plains was cropland and residential land. Although many acres of residential land were included in the flood plain, this land was mostly lawns, with 25 homes within the 100-year flood plain, and 41 homes within the 500-year flood plain in the 2003 aerial photograph. This report describes the data collection activities to refine the hydrologic and hydraulic models used in an earlier study of the Kane County part of the Blackberry Creek watershed and to extend the flood-frequency analysis through water year 2003. The results of the flood-hazard analysis are presented in graphical and tabular form. The hydrologic model, Hydrological Simulation Program - FORTRAN (HSPF), was used to simulate continuous water movement through various land-use patterns 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 the 100-year floodway. The hydraulic model was calibrated and verified using observations during three storms at two crest-stage gages and the U.S. Geological Survey streamflowgaging station near Yorkville. Digital maps of the 100-year and 500-year flood plains and the 100-year floodway for each tributary and the main stem of Blackberry Creek were compiled.

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

NASA Astrophysics Data System (ADS)

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.

Automatic domain updating technique for improving computational efficiency of 2-D flood-inundation simulation

NASA Astrophysics Data System (ADS)

Tanaka, T.; Tachikawa, Y.; Ichikawa, Y.; Yorozu, K.

2017-12-01

Flood is one of the most hazardous disasters and causes serious damage to people and property around the world. To prevent/mitigate flood damage through early warning system and/or river management planning, numerical modelling of flood-inundation processes is essential. In a literature, flood-inundation models have been extensively developed and improved to achieve flood flow simulation with complex topography at high resolution. With increasing demands on flood-inundation modelling, its computational burden is now one of the key issues. Improvements of computational efficiency of full shallow water equations are made from various perspectives such as approximations of the momentum equations, parallelization technique, and coarsening approaches. To support these techniques and more improve the computational efficiency of flood-inundation simulations, this study proposes an Automatic Domain Updating (ADU) method of 2-D flood-inundation simulation. The ADU method traces the wet and dry interface and automatically updates the simulation domain in response to the progress and recession of flood propagation. The updating algorithm is as follow: first, to register the simulation cells potentially flooded at initial stage (such as floodplains nearby river channels), and then if a registered cell is flooded, to register its surrounding cells. The time for this additional process is saved by checking only cells at wet and dry interface. The computation time is reduced by skipping the processing time of non-flooded area. This algorithm is easily applied to any types of 2-D flood inundation models. The proposed ADU method is implemented to 2-D local inertial equations for the Yodo River basin, Japan. Case studies for two flood events show that the simulation is finished within two to 10 times smaller time showing the same result as that without the ADU method.

Annual timing of river floods in the Northeast United States: seasonal characterization and temporal trends

NASA Astrophysics Data System (ADS)

Collins, M. J.

2016-12-01

Increases in flood magnitude and frequency have been documented in climate-sensitive watersheds in the Northeast United States. Associated changes in inundation frequency and/or magnitude, or changes in stream channel form and function, can affect human uses of floodplain environments (e.g., dwellings or transportation infrastructure) as well as aquatic and riparian habitats. Historical changes in flood magnitude and frequency also have important implications for designing floodplain infrastructure and channel modifications because well-accepted statistical methods for design-flood prediction require flood records with stationary means and variances. Changes in flood timing during the year may also be impactful, but have not been studied in detail for the Northeast United States. For example, relatively modest shifts in the timing of winter/spring floods can affect the incidence of ice jam complications. Or, changes in spring or fall flood timing may positively or negatively affect a vulnerable life stage for a migratory fish (e.g., egg setting) depending on whether floods occur more frequently before or after the life history event. With this study I apply an objective, probabilistic method for identifying flood seasonality in climate-sensitive watersheds of the Mid-Atlantic and New England regions (Hydrologic Unit Codes 01 and 02). Temporal trends in the timing of floods within significant flood seasons at a site are then analyzed using a method that employs directional statistics. The analyses are based on partial duration flood series that are an average of 85 years long. Documented changes in flood timing during the year are considered in the context of both potential historical impacts and expectations for future flood timing given regional climate change projections.

Flood hazards studies in the Mississippi River basin using remote sensing

NASA Technical Reports Server (NTRS)

Rango, A.; Anderson, A. T.

1974-01-01

The Spring 1973 Mississippi River flood was investigated using remotely sensed data from ERTS-1. Both manual and automatic analyses of the data indicated that ERTS-1 is extremely useful as a regional tool for flood mamagement. Quantitative estimates of area flooded were made in St. Charles County, Missouri and Arkansas. Flood hazard mapping was conducted in three study areas along the Mississippi River using pre-flood ERTS-1 imagery enlarged to 1:250,000 and 1:100,000 scale. Initial results indicate that ERTS-1 digital mapping of flood prone areas can be performed at 1:62,500 which is comparable to some conventional flood hazard map scales.

Study on Public Flood Risk Cognition and Behavioral Response Based on IEC Strategy

NASA Astrophysics Data System (ADS)

Shen, Xin; Xu, Xiaofeng; Zhou, Guilin; Pan, Shaolin; Mi, Tengfei

2017-11-01

In order to disseminate knowledge and information on flood risks in flood-prone areas, raise public awareness of flood risks and reduce possible damage to the public, a questionnaire survey was coducted among 260 residents of nine selected communities in Jiaozhou City to learn the public awareness and behavioral response to flood risks at different early warning levels. IEC key information of flood risk awareness was modified and formulated through group discussions, in-depth individual interviews and on-site observation. The awareness of residents in the project area was enhanced through the public participation, environmental management and flood management training, which plays a very important role in reducing flood losses.

Impact of urbanization on flood of Shigu creek in Dongguan city

NASA Astrophysics Data System (ADS)

Pan, Luying; Chen, Yangbo; Zhang, Tao

2018-06-01

Shigu creek is a highly urbanized small watershed in Dongguan City. Due to rapid urbanization, quick flood response has been observed, which posted great threat to the flood security of Dongguan City. To evaluate the impact of urbanization on the flood changes of Shigu creek is very important for the flood mitigation of Shigu creek, which will provide insight for flood planners and managers for if to build a larger flood mitigation system. In this paper, the Land cover/use changes of Shigu creek from 1987-2015 induced by urbanization was first extracted from a local database, then, the Liuxihe model, a physically based distributed hydrological model, is employed to simulate the flood processes impacted by urbanization. Precipitation of 3 storms was used for flood processes simulation. The results show that the runoff coefficient and peak flow have increased sharply.

Flood susceptibility analysis through remote sensing, GIS and frequency ratio model

NASA Astrophysics Data System (ADS)

Samanta, Sailesh; Pal, Dilip Kumar; Palsamanta, Babita

2018-05-01

Papua New Guinea (PNG) is saddled with frequent natural disasters like earthquake, volcanic eruption, landslide, drought, flood etc. Flood, as a hydrological disaster to humankind's niche brings about a powerful and often sudden, pernicious change in the surface distribution of water on land, while the benevolence of flood manifests in restoring the health of the thalweg from excessive siltation by redistributing the fertile sediments on the riverine floodplains. In respect to social, economic and environmental perspective, flood is one of the most devastating disasters in PNG. This research was conducted to investigate the usefulness of remote sensing, geographic information system and the frequency ratio (FR) for flood susceptibility mapping. FR model was used to handle different independent variables via weighted-based bivariate probability values to generate a plausible flood susceptibility map. This study was conducted in the Markham riverine precinct under Morobe province in PNG. A historical flood inventory database of PNG resource information system (PNGRIS) was used to generate 143 flood locations based on "create fishnet" analysis. 100 (70%) flood sample locations were selected randomly for model building. Ten independent variables, namely land use/land cover, elevation, slope, topographic wetness index, surface runoff, landform, lithology, distance from the main river, soil texture and soil drainage were used into the FR model for flood vulnerability analysis. Finally, the database was developed for areas vulnerable to flood. The result demonstrated a span of FR values ranging from 2.66 (least flood prone) to 19.02 (most flood prone) for the study area. The developed database was reclassified into five (5) flood vulnerability zones segmenting on the FR values, namely very low (less that 5.0), low (5.0-7.5), moderate (7.5-10.0), high (10.0-12.5) and very high susceptibility (more than 12.5). The result indicated that about 19.4% land area as `very high' and 35.8% as `high' flood vulnerable class. The FR model output was validated with remaining 43 (30%) flood points, where 42 points were marked as correct predictions which evinced an accuracy of 97.7% in prediction. A total of 137292 people are living in those vulnerable zones. The flood susceptibility analysis using this model will be very useful and also an efficient tool to the local government administrators, researchers and planners for devising flood mitigation plans.

77 FR 74142 - Proposed Flood Elevation Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-13

...-2011-0002; Internal Agency Docket No. FEMA-B-1100 and FEMA-B-1222] Proposed Flood Elevation... Base (1% annual-chance) Flood Elevations (BFEs) and modified BFEs for communities participating in the National Flood Insurance Program (NFIP), in accordance with section 110 of the Flood Disaster Protection...

Factors affecting flood insurance purchase in residential properties in Johor, Malaysia

NASA Astrophysics Data System (ADS)

Aliagha, U. G.; Jin, T. E.; Choong, W. W.; Nadzri Jaafar, M.; Ali, H. M.

2014-12-01

High-impact floods have become a virtually annual experience in Malaysia, yet flood insurance has remained a grossly neglected part of comprehensive integrated flood risk management. Using discriminant analysis, this study seeks to identify the demand-side variables that best predict flood insurance purchase and risk aversion between two groups of residential homeowners in three districts of Johor State, Malaysia: those who purchased flood insurance and those who did not. Our results revealed an overall 34% purchase rate, with Kota Tinggi district having the highest (44%) and thus the highest degree of flood risk aversion. The Wilks' lambda F test for equality of group means, standardised discriminant function coefficients, structure correlation, and canonical correlation has clearly shown that there are strong significant attribute differences between the two groups of homeowners, based on the measures of objective flood risk exposure, subjective risk perception, and socio-economic cum demographic variables. However, the measures of subjective risk perception were found to be more predictive of flood insurance purchase and flood risk aversion.

The influence of antecedent conditions on flood risk in sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Bischiniotis, Konstantinos; van den Hurk, Bart; Jongman, Brenden; Coughlan de Perez, Erin; Veldkamp, Ted; de Moel, Hans; Aerts, Jeroen

2018-01-01

Most flood early warning systems have predominantly focused on forecasting floods with lead times of hours or days. However, physical processes during longer timescales can also contribute to flood generation. In this study, we follow a pragmatic approach to analyse the hydro-meteorological pre-conditions of 501 historical damaging floods from 1980 to 2010 in sub-Saharan Africa. These are separated into (a) weather timescale (0-6 days) and (b) seasonal timescale conditions (up to 6 months) before the event. The 7-day precipitation preceding a flood event (PRE7) and the standardized precipitation evapotranspiration index (SPEI) are analysed for the two timescale domains, respectively. Results indicate that high PRE7 does not always generate floods by itself. Seasonal SPEIs, which are not directly correlated with PRE7, exhibit positive (wet) values prior to most flood events across different averaging times, indicating a relationship with flooding. This paper provides evidence that bringing together weather and seasonal conditions can lead to improved flood risk preparedness.

Comparison of floods non-stationarity detection methods: an Austrian case study

NASA Astrophysics Data System (ADS)

Salinas, Jose Luis; Viglione, Alberto; Blöschl, Günter

2016-04-01

Non-stationarities in flood regimes have a huge impact in any mid and long term flood management strategy. In particular the estimation of design floods is very sensitive to any kind of flood non-stationarity, as they should be linked to a return period, concept that can be ill defined in a non-stationary context. Therefore it is crucial when analyzing existent flood time series to detect and, where possible, attribute flood non-stationarities to changing hydroclimatic and land-use processes. This works presents the preliminary results of applying different non-stationarity detection methods on annual peak discharges time series over more than 400 gauging stations in Austria. The kind of non-stationarities analyzed include trends (linear and non-linear), breakpoints, clustering beyond stochastic randomness, and detection of flood rich/flood poor periods. Austria presents a large variety of landscapes, elevations and climates that allow us to interpret the spatial patterns obtained with the non-stationarity detection methods in terms of the dominant flood generation mechanisms.

Reconstruction of the 1945 Wieringermeer Flood

NASA Astrophysics Data System (ADS)

Hoes, O. A. C.; Hut, R. W.; van de Giesen, N. C.; Boomgaard, M.

2013-03-01

The present state-of-the-art in flood risk assessment focuses on breach models, flood propagation models, and economic modelling of flood damage. However, models need to be validated with real data to avoid erroneous conclusions. Such reference data can either be historic data, or can be obtained from controlled experiments. The inundation of the Wieringermeer polder in the Netherlands in April 1945 is one of the few examples for which sufficient historical information is available. The objective of this article is to compare the flood simulation with flood data from 1945. The context, the breach growth process and the flood propagation are explained. Key findings for current flood risk management addresses the importance of the drainage canal network during the inundation of a polder, and the uncertainty that follows from not knowing the breach growth parameters. This case study shows that historical floods provide valuable data for the validation of models and reveal lessons that are applicable in current day flood risk management.

Factors affecting flood insurance penetration in residential properties in Johor Malaysia

NASA Astrophysics Data System (ADS)

Godwin Aliagha, U.; Ewe Jin, T.; Weng Choong, W.; Nadzri Jaafar, M.

2014-04-01

High impact flood has virtually become an annual experience in Malaysia, yet flood insurance has remained a grossly neglected part of comprehensive integrated flood risk management. Using discriminant analysis, this study seeks to indentify the demand-side variables that best predict flood insurance penetration and risk aversion between two groups of residential homeowners in three districts of Johor State, Malaysia: those who purchased flood insurance and the group that did not. Our result revealed 34% penetration rate with Kota Tinggi district having the highest penetration (44%) and thus, the highest degree of flood risk aversion. The Wilks' Lambda F test for equality of group means, SCDFC, structure correlation and canonical correlation have clearly shown that there are strong significant attribute differences between the two groups of homeowners based on measures of objective flood risk exposure, subjective risk perception, and socio-economic cum demographic variables. However, measures of subjective risk perception were found more predictive of flood insurance penetration and flood risk aversion.

Managing runoff and flow pathways in a small rural catchment to reduce flood risk with other multi-purpose benefits

NASA Astrophysics Data System (ADS)

Wilkinson, Mark; Welton, Phil; Kerr, Peter; Quinn, Paul; Jonczyk, Jennine

2010-05-01

From 2000 to 2009 there have been a high number of flood events throughout Northern Europe. Meanwhile, there is a demand for land in which to construct homes and businesses on, which is encroaching on land which is prone to flooding. Nevertheless, flood defences usually protect us from this hazard. However, the severity of floods and this demand for land has increased the number of homes which have been flooded in the past ten years. Public spending on flood defences can only go so far which targets the large populations first. Small villages and communities, where in many cases normal flood defences are not cost effective, tend to wait longer for flood mitigation strategies. The Belford Burn (Northumberland, UK) catchment is a small rural catchment that drains an area of 6 km2. It flows through the village of Belford. There is a history of flooding in Belford, with records of flood events dating back to 1877. Normal flood defences are not suitable for this catchment as it failed the Environment Agency (EA) cost benefit criteria for support. There was a desire by the local EA Flood Levy Team and the Northumbria Regional Flood Defence Committee at the Environment Agency to deliver an alternative catchment-based solution to the problem. The EA North East Flood Levy team and Newcastle University have created a partnership to address the flood problem using soft engineered runoff management features. Farm Integrated Runoff Management (FIRM) plans manage flow paths directly by storing slowing and filtering runoff at source on farms. The features are multipurpose addressing water quality, trapping sediment, creating new habitats and storing and attenuating flood flow. Background rainfall and stream stage data have been collected since November 2007. Work on the first mitigation features commenced in July 2008. Since that date five flood events have occurred in the catchment. Two of these flood events caused widespread damage in other areas of the county. However, in Belford only two houses were flooded. Data from the catchment and mitigation features showed that the defence measures resulted in an increase in travel time of the peak and attenuated high flows which would have usually travelled quickly down the channel to the village. For example, the pilot feature appears to have increased the travel time of a flood peak at the top of the catchment from 20 minutes to 35 minutes over a 1 km stretch of channel. There are currently ten active mitigation features present in the catchment. More features are planned for construction this year. Early data from the catchment indicates that the runoff attenuation features are having an impact on reducing flood flows in the channel and also slowing down the flood peak. At the same time the multi-purpose aspects of the features are apparent.

12 CFR Appendix A to Part 339 - Sample Form of Notice of Special Flood Hazards and Availability of Federal Disaster Relief...

Code of Federal Regulations, 2011 CFR

2011-01-01

... SPECIAL FLOOD HAZARDS Pt. 339, App. A Appendix A to Part 339—Sample Form of Notice of Special Flood... you do not purchase flood insurance. The flood insurance must be maintained for the life of the loan. If you fail to purchase or renew flood insurance on the property, Federal law authorizes and requires...

12 CFR Appendix A to Part 339 - Sample Form of Notice of Special Flood Hazards and Availability of Federal Disaster Relief...

Code of Federal Regulations, 2010 CFR

2010-01-01

... SPECIAL FLOOD HAZARDS Pt. 339, App. A Appendix A to Part 339—Sample Form of Notice of Special Flood... you do not purchase flood insurance. The flood insurance must be maintained for the life of the loan. If you fail to purchase or renew flood insurance on the property, Federal law authorizes and requires...

Transcriptomic analysis reveals the flooding tolerant mechanism in flooding tolerant line and abscisic acid treated soybean.

PubMed

Yin, Xiaojian; Hiraga, Susumu; Hajika, Makita; Nishimura, Minoru; Komatsu, Setsuko

2017-03-01

Soybean is highly sensitive to flooding stress and exhibits markedly reduced plant growth and grain yield under flooding conditions. To explore the mechanisms underlying initial flooding tolerance in soybean, RNA sequencing-based transcriptomic analysis was performed using a flooding-tolerant line and ABA-treated soybean. A total of 31 genes included 12 genes that exhibited similar temporal patterns were commonly changed in these plant groups in response to flooding and they were mainly involved in RNA regulation and protein metabolism. The mRNA expression of matrix metalloproteinase, glucose-6-phosphate isomerase, ATPase family AAA domain-containing protein 1, and cytochrome P450 77A1 was up-regulated in wild-type soybean under flooding conditions; however, no changes were detected in the flooding-tolerant line or ABA-treated soybean. The mRNA expression of cytochrome P450 77A1 was specifically up-regulated in root tips by flooding stress, but returned to the level found in control plants following treatment with the P450 inhibitor uniconazole. The survival ratio and root fresh weight of plants were markedly improved by 3-h uniconazole treatment under flooding stress. Taken together, these results suggest that cytochrome P450 77A1 is suppressed by uniconazole treatment and that this inhibition may enhance soybean tolerance to flooding stress.

Early physiological flood tolerance is followed by slow post-flooding root recovery in the dryland riparian tree Eucalyptus camaldulensis subsp. refulgens.

PubMed

Argus, R E; Colmer, T D; Grierson, P F

2015-06-01

We investigated physiological and morphological responses to flooding and recovery in Eucalyptus camaldulensis subsp. refulgens, a riparian tree species from a dryland region prone to intense episodic floods. Seedlings in soil flooded for 88 d produced extensive adventitious roots, displayed stem hypertrophy (stem diameter increased by 93%) and increased root porosity owing to aerenchyma formation. Net photosynthesis (Pn) and stomatal conductance (gs) were maintained for at least 2 weeks of soil flooding, contrasting with previous studies of other subspecies of E. camaldulensis. Gradual declines followed in both gs (30% less than controls) and Pn (19% less). Total leaf soluble sugars did not differ between flooded and control plants. Root mass did not recover 32 d after flooding ceased, but gs was not lower than controls, suggesting the root system was able to functionally compensate. However, the limited root growth during recovery after flooding was surprising given the importance of extensive root systems in dryland environments. We conclude that early flood tolerance could be an adaptation to capitalize on scarce water resources in a water-limited environment. Overall, our findings highlight the need to assess flooding responses in relation to a species' fitness for particular flood regimes or ecological niches. © 2014 John Wiley & Sons Ltd.

Quantitative Proteomics Reveals the Flooding-Tolerance Mechanism in Mutant and Abscisic Acid-Treated Soybean.

PubMed

Yin, Xiaojian; Nishimura, Minoru; Hajika, Makita; Komatsu, Setsuko

2016-06-03

Flooding negatively affects the growth of soybean, and several flooding-specific stress responses have been identified; however, the mechanisms underlying flooding tolerance in soybean remain unclear. To explore the initial flooding tolerance mechanisms in soybean, flooding-tolerant mutant and abscisic acid (ABA)-treated plants were analyzed. In the mutant and ABA-treated soybeans, 146 proteins were commonly changed at the initial flooding stress. Among the identified proteins, protein synthesis-related proteins, including nascent polypeptide-associated complex and chaperonin 20, and RNA regulation-related proteins were increased in abundance both at protein and mRNA expression. However, these proteins identified at the initial flooding stress were not significantly changed during survival stages under continuous flooding. Cluster analysis indicated that glycolysis- and cell wall-related proteins, such as enolase and polygalacturonase inhibiting protein, were increased in abundance during survival stages. Furthermore, lignification of root tissue was improved even under flooding stress. Taken together, these results suggest that protein synthesis- and RNA regulation-related proteins play a key role in triggering tolerance to the initial flooding stress in soybean. Furthermore, the integrity of cell wall and balance of glycolysis might be important factors for promoting tolerance of soybean root to flooding stress during survival stages.

Dependence of flood risk perceptions on socioeconomic and objective risk factors

NASA Astrophysics Data System (ADS)

Botzen, W. J. W.; Aerts, J. C. J. H.; van den Bergh, J. C. J. M.

2009-10-01

This study examines flood risk perceptions of individuals in the Netherlands using a survey of approximately 1000 homeowners. Perceptions of a range of aspects of flood risk are elicited. Various statistical models are used to estimate the influence of socioeconomic and geographical characteristics, personal experience with flooding, knowledge of flood threats, and individual risk attitudes on shaping risk belief. The study shows that in general, perceptions of flood risk are low. An analysis of the factors determining risk perceptions provides four main insights relevant for policy makers and insurers. First, differences in expected risk are consistently related to actual risk levels, since individuals in the vicinity of a main river and low-lying areas generally have elevated risk perceptions. Second, individuals in areas unprotected by dikes tend to underestimate their risk of flooding. Third, individuals with little knowledge of the causes of flood events have lower perceptions of flood risk. Fourth, there is some evidence that older and more highly educated individuals have a lower flood risk perception. The findings indicate that increasing knowledge of citizens about the causes of flooding may increase flood risk awareness. It is especially important to target individuals who live in areas unprotected by dike infrastructure, since they tend to be unaware of or ignore the high risk exposure faced.

Flooding and Atmospheric Rivers across the Western United States

NASA Astrophysics Data System (ADS)

Villarini, G.; Barth, N. A.; White, K. D.

2017-12-01

Flood frequency analysis across the western United States is complicated by annual peak flow records that frequently contain flows generated from distinctly different flood generating mechanisms. Among the different flood agents, atmospheric rivers (ARs) are responsible for large, regional scale floods. USGS streamgaging stations in the central Columbia River Basin in the Pacific Northwest, the Sierra Nevada, the central and southern California coast, and central Arizona show a mixture of 30-70% AR-generated flood peaks among the complete period of record. Bulletin17B and its proposed update (Draft Bulletin 17C) continue to recognize difficulties in determining flood frequency estimates among streamflow records that contain flood peaks coming from different flood-generating mechanisms, as is the case in the western United States. They recommend developing separate frequency curves when the hydrometeorologic mechanisms that generated the annual peak flows can be separated into distinct subpopulations. Yet challenges arise when trying to consistently quantify the physical (hydrometeorologic) processes that generated the observed flows, and even more when trying to account for them in flood frequency estimation. This study provides a general statistical framework to perform a process-driven flood frequency analysis using a weighted mixed population approach, highlighting the role that ARs play on the flood peak distribution.

Detecting seasonal flood changes in the Upper Danube River basin

NASA Astrophysics Data System (ADS)

Kohnová, Silvia; Jeneiová, Katarína; Parajka, Juraj; Hall, Julia; Marková, Romana

2017-04-01

Due to a number of large-scale floods observed worldwide in recent years, the analysis of changes in long-term hydrological time series is becoming increasingly important. This study focuses on the Upper Danube region, which was struck by many flood events in the past decade. The flood seasonality of the study region, defined as the area of Germany, the Czech Republic, Switzerland, Austria and Slovakia, is examined to interpret the dominant flood processes. A spatial assessment of the seasonality indices of the annual maximum discharges and the seasonal discharges (derived from daily average discharges) was conducted for 117 gauging stations. Hot spots for potential changes in the mean dates of occurrence of the discharges were identified, and the results were linked with derived spatial characteristics for the catchments. The first results of the study of the seasonal discharges revealed that the variability of occurrence of summer floods is higher than winter floods in lowlands of the upper Danube catchment. In high Alpine catchments the winter floods variability of occurrence is the same or higher than for the summer floods. The summer season floods tend to appear for all catchment sizes in the same time period. With increased magnitude of floods in the summer season, the variability of occurrence of the floods is higher.

Development of high-resolution multi-scale modelling system for simulation of coastal-fluvial urban flooding

NASA Astrophysics Data System (ADS)

Comer, Joanne; Indiana Olbert, Agnieszka; Nash, Stephen; Hartnett, Michael

2017-02-01

Urban developments in coastal zones are often exposed to natural hazards such as flooding. In this research, a state-of-the-art, multi-scale nested flood (MSN_Flood) model is applied to simulate complex coastal-fluvial urban flooding due to combined effects of tides, surges and river discharges. Cork city on Ireland's southwest coast is a study case. The flood modelling system comprises a cascade of four dynamically linked models that resolve the hydrodynamics of Cork Harbour and/or its sub-region at four scales: 90, 30, 6 and 2 m. Results demonstrate that the internalization of the nested boundary through the use of ghost cells combined with a tailored adaptive interpolation technique creates a highly dynamic moving boundary that permits flooding and drying of the nested boundary. This novel feature of MSN_Flood provides a high degree of choice regarding the location of the boundaries to the nested domain and therefore flexibility in model application. The nested MSN_Flood model through dynamic downscaling facilitates significant improvements in accuracy of model output without incurring the computational expense of high spatial resolution over the entire model domain. The urban flood model provides full characteristics of water levels and flow regimes necessary for flood hazard identification and flood risk assessment.

Multi-dimensional flood vulnerability assessment using data envelopment analysis

NASA Astrophysics Data System (ADS)

Zahid, Zalina; Saharizan, Nurul Syuhada; Hamzah, Paezah; Hussin, Siti Aida Sheikh; Khairi, Siti Shaliza Mohd

2017-11-01

Malaysia has been greatly impacted by flood during monsoon seasons. Even though flood prone areas are well identified, assessment on the vulnerability of the disaster is lacking. Assessment of flood vulnerability, defined as the potential for loss when a disaster occurs, is addressed in this paper. The focus is on the development of flood vulnerability measurement in 11 states in Peninsular Malaysia using a non-parametric approach of Data Envelopment Analysis. Scores for three dimensions of flood vulnerability (Population Vulnerability, Social Vulnerability and Biophysical) were calculated using secondary data of selected input and output variables across an 11-year period from 2004 to 2014. The results showed that Johor and Pahang were the most vulnerable to flood in terms of Population Vulnerability, followed by Kelantan, the most vulnerable to flood in terms of Social Vulnerability and Kedah, Pahang and Terengganu were the most vulnerable to flood in terms of Biophysical Vulnerability among the eleven states. The results also showed that the state of Johor, Pahang and Kelantan to be most vulnerable across the three dimensions. Flood vulnerability assessment is important as it provides invaluable information that will allow the authority to identify and develop plans for flood mitigation and to reduce the vulnerability of flood at the affected regions.

Risk of Flood-Related Diseases of Eyes, Skin and Gastrointestinal Tract in Taiwan: A Retrospective Cohort Study

PubMed Central

Huang, Ling-Ya; Wang, Yu-Chun; Wu, Chin-Ching

2016-01-01

Floods are known to cause serious environmental damage and health impacts. Studies on flood-related diseases have been primarily on individual events, and limited evidence could be drawn on potential health impacts from floods using large population data. This study used reimbursement records of one million people of the Taiwan National Health Insurance program to compare incident diseases of the eyes, skin and gastrointestinal (GI) tract associated with floods. Incidence rates for the selected diseases were calculated according to outpatient/emergency visit data. The incidence rates were evaluated by flood status: in 10 days before floods, during floods and within 10 days after the floods receded. Outpatient/emergency visit rates for the eye, skin and GI tract diseases were highest after floods and lowest during floods. Results from multivariate Poisson regression analyses showed that, when compared with the incidence in 10 days before floods, the incidence rate ratios (IRR) of diseases within 10 days after floods were 1.15 (95% confidence interval (CI) = 1.10–1.20) for eyes, 1.08 (95% C.I. = 1.05–1.10) for skin, and 1.11 (95% CI = 1.08–1.14) for GI tract, after controlling for covariates. All risks increased with ambient temperature. V-shaped trends were found between age and eye diseases, and between age and GI tract diseases. In contrast, the risk of skin diseases increased with age. In conclusion, more diseases of eyes, skin and GI tract could be diagnosed after the flood. PMID:27171415

A Vulnerability-Based, Bottom-up Assessment of Future Riverine Flood Risk Using a Modified Peaks-Over-Threshold Approach and a Physically Based Hydrologic Model

NASA Astrophysics Data System (ADS)

Knighton, James; Steinschneider, Scott; Walter, M. Todd

2017-12-01

There is a chronic disconnection among purely probabilistic flood frequency analysis of flood hazards, flood risks, and hydrological flood mechanisms, which hamper our ability to assess future flood impacts. We present a vulnerability-based approach to estimating riverine flood risk that accommodates a more direct linkage between decision-relevant metrics of risk and the dominant mechanisms that cause riverine flooding. We adapt the conventional peaks-over-threshold (POT) framework to be used with extreme precipitation from different climate processes and rainfall-runoff-based model output. We quantify the probability that at least one adverse hydrologic threshold, potentially defined by stakeholders, will be exceeded within the next N years. This approach allows us to consider flood risk as the summation of risk from separate atmospheric mechanisms, and supports a more direct mapping between hazards and societal outcomes. We perform this analysis within a bottom-up framework to consider the relevance and consequences of information, with varying levels of credibility, on changes to atmospheric patterns driving extreme precipitation events. We demonstrate our proposed approach using a case study for Fall Creek in Ithaca, NY, USA, where we estimate the risk of stakeholder-defined flood metrics from three dominant mechanisms: summer convection, tropical cyclones, and spring rain and snowmelt. Using downscaled climate projections, we determine how flood risk associated with a subset of mechanisms may change in the future, and the resultant shift to annual flood risk. The flood risk approach we propose can provide powerful new insights into future flood threats.

Impact of the timing of a SAR image acquisition on the calibration of a flood inundation model

NASA Astrophysics Data System (ADS)

Gobeyn, Sacha; Van Wesemael, Alexandra; Neal, Jeffrey; Lievens, Hans; Eerdenbrugh, Katrien Van; De Vleeschouwer, Niels; Vernieuwe, Hilde; Schumann, Guy J.-P.; Di Baldassarre, Giuliano; Baets, Bernard De; Bates, Paul D.; Verhoest, Niko E. C.

2017-02-01

Synthetic Aperture Radar (SAR) data have proven to be a very useful source of information for the calibration of flood inundation models. Previous studies have focused on assigning uncertainties to SAR images in order to improve flood forecast systems (e.g. Giustarini et al. (2015) and Stephens et al. (2012)). This paper investigates whether the timing of a SAR acquisition of a flood has an important impact on the calibration of a flood inundation model. As no suitable time series of SAR data exists, we generate a sequence of consistent SAR images through the use of a synthetic framework. This framework uses two available ERS-2 SAR images of the study area, one taken during the flood event of interest, the second taken during a dry reference period. The obtained synthetic observations at different points in time during the flood event are used to calibrate the flood inundation model. The results of this study indicate that the uncertainty of the roughness parameters is lower when the model is calibrated with an image taken before rather than during or after the flood peak. The results also show that the error on the modelled extent is much lower when the model is calibrated with a pre-flood peak image than when calibrated with a near-flood peak or a post-flood peak image. It is concluded that the timing of the SAR image acquisition of the flood has a clear impact on the model calibration and consequently on the precision of the predicted flood extent.

Flood risk analysis for flood control and sediment transportation: a case study in the catchments of the Loess Plateau, China

NASA Astrophysics Data System (ADS)

Wang, Y.; Chang, J.; Guo, A.

2017-12-01

Traditional flood risk analysis focuses on the probability of flood events exceeding the design flood of downstream hydraulic structures while neglecting the influence of sedimentation in river channels on flood control systems. Given this focus, a univariate and copula-based bivariate hydrological risk framework focusing on flood control and sediment transport is proposed in the current work. Additionally, the conditional probabilities of occurrence of different flood events under various extreme precipitation scenarios are estimated by exploiting the copula model. Moreover, a Monte Carlo-based algorithm is used to evaluate the uncertainties of univariate and bivariate hydrological risk. Two catchments located on the Loess plateau are selected as study regions: the upper catchments of the Xianyang and Huaxian stations (denoted as UCX and UCH, respectively). The results indicate that (1) 2-day and 3-day consecutive rainfall are highly correlated with the annual maximum flood discharge (AMF) in UCX and UCH, respectively; and (2) univariate and bivariate return periods, risk and reliability for the purposes of flood control and sediment transport are successfully estimated. Sedimentation triggers higher risks of damaging the safety of local flood control systems compared with the AMF, exceeding the design flood of downstream hydraulic structures in the UCX and UCH. Most importantly, there was considerable sampling uncertainty in the univariate and bivariate hydrologic risk analysis, which would greatly challenge measures of future flood mitigation. The proposed hydrological risk framework offers a promising technical reference for flood risk analysis in sandy regions worldwide.

Nonstationary frequency analysis for the trivariate flood series of the Weihe River

NASA Astrophysics Data System (ADS)

Jiang, Cong; Xiong, Lihua

2016-04-01

Some intensive human activities such as water-soil conservation can significantly alter the natural hydrological processes of rivers. In this study, the effect of the water-soil conservation on the trivariate flood series from the Weihe River located in the Northwest China is investigated. The annual maxima daily discharge, annual maxima 3-day flood volume and annual maxima 5-day flood volume are chosen as the study data and used to compose the trivariate flood series. The nonstationarities in both the individual univariate flood series and the corresponding antecedent precipitation series generating the flood events are examined by the Mann-Kendall trend test. It is found that all individual univariate flood series present significant decreasing trend, while the antecedent precipitation series can be treated as stationary. It indicates that the increase of the water-soil conservation land area has altered the rainfall-runoff relationship of the Weihe basin, and induced the nonstationarities in the three individual univariate flood series. The time-varying moments model based on the Pearson type III distribution is applied to capture the nonstationarities in the flood frequency distribution with the water-soil conservation land area introduced as the explanatory variable of the flood distribution parameters. Based on the analysis for each individual univariate flood series, the dependence structure among the three univariate flood series are investigated by the time-varying copula model also with the water-soil conservation land area as the explanatory variable of copula parameters. The results indicate that the dependence among the trivariate flood series is enhanced by the increase of water-soil conservation land area.

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

PubMed

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.

"Know What to Do If You Encounter a Flash Flood": Mental Models Analysis for Improving Flash Flood Risk Communication and Public Decision Making.

PubMed

Lazrus, Heather; Morss, Rebecca E; Demuth, Julie L; Lazo, Jeffrey K; Bostrom, Ann

2016-02-01

Understanding how people view flash flood risks can help improve risk communication, ultimately improving outcomes. This article analyzes data from 26 mental models interviews about flash floods with members of the public in Boulder, Colorado, to understand their perspectives on flash flood risks and mitigation. The analysis includes a comparison between public and professional perspectives by referencing a companion mental models study of Boulder-area professionals. A mental models approach can help to diagnose what people already know about flash flood risks and responses, as well as any critical gaps in their knowledge that might be addressed through improved risk communication. A few public interviewees mentioned most of the key concepts discussed by professionals as important for flash flood warning decision making. However, most interviewees exhibited some incomplete understandings and misconceptions about aspects of flash flood development and exposure, effects, or mitigation that may lead to ineffective warning decisions when a flash flood threatens. These include important misunderstandings about the rapid evolution of flash floods, the speed of water in flash floods, the locations and times that pose the greatest flash flood risk in Boulder, the value of situational awareness and environmental cues, and the most appropriate responses when a flash flood threatens. The findings point to recommendations for ways to improve risk communication, over the long term and when an event threatens, to help people quickly recognize and understand threats, obtain needed information, and make informed decisions in complex, rapidly evolving extreme weather events such as flash floods. © 2015 Society for Risk Analysis.

Impact of the Timing of a SAR Image Acquisition on the Calibration of a Flood Inundation Model

NASA Technical Reports Server (NTRS)

Gobeyn, Sacha; Van Wesemael, Alexandra; Neal, Jeffrey; Lievens, Hans; Van Eerdenbrugh, Katrien; De Vleeschouwer, Niels; Vernieuwe, Hilde; Schumann, Guy J.-P.; Di Baldassarre, Giuliano; De Baets, Bernard;

Formation and evolution of valley-bottom and channel features, Lower Deschutes River, Oregon

USGS Publications Warehouse

Curran, Janet H.; O'Conner, Jim E.; O'Conner, Jim E.; Grant, Gordon E.

2003-01-01

Primary geologic and geomorphic processes that formed valley-bottom and channel features downstream from the Pelton-Round Butte dam complex are inferred from a canyon-long analysis of feature morphology, composition, location, and spatial distribution. Major controls on valley-bottom morphology are regional tectonics, large landslides, and outsized floods (floods with return periods greater than 1000 yrs), which include the late Holocene Outhouse Flood and several Quaternary landslide dam failures. Floods with a return period on the order of 100 yrs, including historical floods in 1996, 1964, and 1861, contribute to fan building and flood plain formation only within the resistant framework established by the major controls. Key processes in the formation of channel features, in particular the 153 islands and 23 large rapids, include long-term bedrock erosion, outsized floods, and century-scale floods. Historical analysis of channel conditions since 1911 indicates that the largest islands, which are cored by outsized-flood deposits, locally control channel location, although their margins are substantially modified during annual- to century-scale floods. Islands cored by bedrock have changed little. Islands formed by annual- to century-scale floods are more susceptible to dynamic interactions between tributary sediment inputs, mainstem flow hydraulics, and perhaps riparian vegetation. Temporal patterns of island change in response to the sequence of 20th century flooding indicate that many islands accreted sediment during annual- to decadal-scale floods, but eroded during larger century-scale floods. There is, however, no clear trend of long-term changes in patterns of island growth, movement, or erosion either spatially or temporally within the lower Deschutes River.

Dynamics of flood water infiltration and ground water recharge in hyperarid desert.

PubMed

Dahan, Ofer; Tatarsky, Boaz; Enzel, Yehouda; Kulls, Christoph; Seely, Mary; Benito, Gererdo

2008-01-01

A study on flood water infiltration and ground water recharge of a shallow alluvial aquifer was conducted in the hyperarid section of the Kuiseb River, Namibia. The study site was selected to represent a typical desert ephemeral river. An instrumental setup allowed, for the first time, continuous monitoring of infiltration during a flood event through the channel bed and the entire vadose zone. The monitoring system included flexible time domain reflectometry probes that were designed to measure the temporal variation in vadose zone water content and instruments to concurrently measure the levels of flood and ground water. A sequence of five individual floods was monitored during the rainy season in early summer 2006. These newly generated data served to elucidate the dynamics of flood water infiltration. Each flood initiated an infiltration event which was expressed in wetting of the vadose zone followed by a measurable rise in the water table. The data enabled a direct calculation of the infiltration fluxes by various independent methods. The floods varied in their stages, peaks, and initial water contents. However, all floods produced very similar flux rates, suggesting that the recharge rates are less affected by the flood stages but rather controlled by flow duration and available aquifer storage under it. Large floods flood the stream channel terraces and promote the larger transmission losses. These, however, make only a negligible contribution to the recharge of the ground water. It is the flood duration within the active streambed, which may increase with flood magnitude that is important to the recharge process.

Simulations of Flooding on Pea River and Whitewater Creek in the Vicinity of the Proposed Elba Bypass at Elba, Alabama

USGS Publications Warehouse

Hedgecock, T. Scott

2003-01-01

A two-dimensional finite-element surface-water model was used to study the effects of proposed modifications to the State Highway 203 corridor (proposed Elba Bypass/relocated U.S. Highway 84) on water-surface elevations and flow distributions during flooding in the Pea River and Whitewater Creek Basins at Elba, Coffee County, Alabama. Flooding was first simulated for the March 17, 1990, flood, using the 1990 flood-plain conditions to calibrate the model to match measured data collected by the U.S. Geological Survey and the U.S. Army Corps of Engineers after the flood. After model calibration, the effects of flooding were simulated for four scenarios: (1) floods having the 50- and 100-year recurrence intervals for the existing flood-plain, bridge, highway, and levee conditions; (2) floods having the 50- and 100-year recurrence intervals for the existing flood-plain and levee conditions with the State Highway 203 embankment and bridge removed; (3) floods having the 50- and 100-year recurrence intervals for the existing flood-plain, bridge, and highway conditions with proposed modifications (elevating) to the levee; and (4) floods having the 50- and 100-year recurrence intervals for the proposed conditions reflecting the Elba Bypass and modified levee. The simulation of floodflow for the Pea River and Whitewater Creek flood of March 17, 1990, in the study reach compared closely to flood profile data obtained after the flood. The flood of March 17, 1990, had an estimated peak discharge of 58,000 cubic feet per second at the gage (just below the confluence) and was estimated to be between a 50-year and 100-year flood event. The estimated peak discharge for Pea River and Whitewater Creek was 40,000 and 42,000 cubic feet per second, respectively. Simulation of floodflows for the 50-year flood (51,400 cubic feet per second) at the gage for existing flood-plain, bridge, highway, and levee conditions indicated that about 31 percent of the peak flow was conveyed by the State Highway 203 bridge over Whitewater Creek, approximately 12 percent overtopped the State Highway 203 embankment, and about 57 percent was conveyed by the Pea River flood plain east of State Highway 125. For this simulation, flow from Pea River (2,380 cubic feet per second) overtopped State Highway 125 and crossed over into the Whitewater Creek flood plain north of State Highway 203, creating one common flood plain. The water-surface elevation estimated at the downstream side of the State Highway 203 bridge crossing Whitewater Creek was 202.82 feet. The girders for both the State Highway 203 and U.S. Highway 84 bridges were partially submerged, but U.S. Highway 84 was not overtopped. For the 100-year flood (63,500 cubic feet per second) at the gage, the simulation indicated that about 25 percent of the peak flow was conveyed by the State Highway 203 bridge over Whitewater Creek, approximately 24 percent overtopped the State Highway 203 embankment, and about 51 percent was conveyed by the Pea River flood plain east of State Highway 125. The existing levee adjacent to Whitewater Creek was overtopped by a flow of 3,200 cubic feet per second during the 100-year flood. For this simulation, flow from Pea River (6,710 cubic feet per second) overtopped State Highway 125 and crossed over into the Whitewater Creek flood plain north of State Highway 203. The water-surface elevation estimated at the downstream side of the State Highway 203 bridge crossing Whitewater Creek was 205.60 feet. The girders for both the State Highway 203 and U.S. Highway 84 bridges were partially submerged, and the west end of the U.S. Highway 84 bridge was overtopped. Simulation of floodflows for the 50-year flood at the gage for existing flood-plain and levee conditions, but with the State Highway 203 embankment and bridge removed, yielded a lower water-surface elevation (202.90 feet) upstream of this bridge than that computed for the existing conditions. For the 100-year flood, the simulation indi

Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees

PubMed Central

Ranger, Christopher M.; Schultz, Peter B.; Frank, Steven D.; Chong, Juang H.; Reding, Michael E.

2015-01-01

Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves detection of stress-induced ethanol emission and early colonization of living but weakened trees. PMID:26134522

Non-Native Ambrosia Beetles as Opportunistic Exploiters of Living but Weakened Trees.

PubMed

Ranger, Christopher M; Schultz, Peter B; Frank, Steven D; Chong, Juang H; Reding, Michael E

2015-01-01

Exotic Xylosandrus spp. ambrosia beetles established in non-native habitats have been associated with sudden and extensive attacks on a diverse range of living trees, but factors driving their shift from dying/dead hosts to living and healthy ones are not well understood. We sought to characterize the role of host physiological condition on preference and colonization by two invaders, Xylosandrus germanus and Xylosandrus crassiusculus. When given free-choice under field conditions among flooded and non-flooded deciduous tree species of varying intolerance to flooding, beetles attacked flood-intolerant tree species over more tolerant species within 3 days of initiating flood stress. In particular, flood-intolerant flowering dogwood (Cornus florida) sustained more attacks than flood-tolerant species, including silver maple (Acer saccharinum) and swamp white oak (Quercus bicolor). Ethanol, a key host-derived attractant, was detected at higher concentrations 3 days after initiating flooding within stems of flood intolerant species compared to tolerant and non-flooded species. A positive correlation was also detected between ethanol concentrations in stem tissue and cumulative ambrosia beetle attacks. When adult X. germanus and X. crassiusculus were confined with no-choice to stems of flood-stressed and non-flooded C. florida, more ejected sawdust resulting from tunneling activity was associated with the flood-stressed trees. Furthermore, living foundresses, eggs, larvae, and pupae were only detected within galleries created in stems of flood-stressed trees. Despite a capability to attack diverse tree genera, X. germanus and X. crassiusculus efficiently distinguished among varying host qualities and preferentially targeted trees based on their intolerance of flood stress. Non-flooded trees were not preferred or successfully colonized. This study demonstrates the host-selection strategy exhibited by X. germanus and X. crassiusculus in non-native habitats involves detection of stress-induced ethanol emission and early colonization of living but weakened trees.

Comparison of Alaskan Flood Stages: Annual Exceedance Probability vs. Impact Based Stages and Recommendations for the Future

NASA Astrophysics Data System (ADS)

Anderson, B. J.

2016-12-01

The Alaska River Forecasting Center (APRFC) issues water level forecasts that are used in conjunction with established flood stages to provide flood warning and advisory information to the public. The APRFC typically establishes flood stages based on observed impacts but Alaska has sparse empirical data (e.g., few impact surveys). Thus service hydrologists in Alaska use flood frequency analysis (LP3 distribution) to estimate flood stages from annual exceedance probabilities (AEPs) (Curran et al, 2016). Previously, the APRFC has maintained that bankfull stage corresponds to the 50% AEP, minor to 10-20% AEP, moderate to 2.5-7% AEP, and major to 1-2% AEP, but we now need to statistically verify this relationship. Our objective is therefore to validate the relationship between flood stages and stage associated with the 50, 20, 10, 4, 2, 1, 0.2, and 0.5 AEPs to provide recommendations for improved flood forecasting. We studied the relationship between AEP and flood stage for all gages (56) used by the APRFC that had rating curves not older than 3 years, flood stages based on observed impacts, and at least 10 years of peak annual stage data. The analysis found relatively strong relationships for all flood stages, except for bankfull stage, but with some differences when compared to the traditionally referenced relationship. Major flood stage appears to be most similar to the 1-.2% AEP (100-500 year RI) while moderate flood stage best fits the 2-4% AEP (25-50 year interval). Gages showing a difference in stage of 2 ft or greater exhibited this difference across all flood stages, which we link to site specific qualities such as susceptibility to ice-jam flooding. We present this method as a possible application to Alaskan Rivers as a general flood stage guideline.

Climate, orography and scale controls on flood frequency in Triveneto (Italy)

NASA Astrophysics Data System (ADS)

Persiano, Simone; Castellarin, Attilio; Salinas, Jose Luis; Domeneghetti, Alessio; Brath, Armando

2016-05-01

The growing concern about the possible effects of climate change on flood frequency regime is leading Authorities to review previously proposed reference procedures for design-flood estimation, such as national flood frequency models. Our study focuses on Triveneto, a broad geographical region in North-eastern Italy. A reference procedure for design flood estimation in Triveneto is available from the Italian NCR research project "VA.PI.", which considered Triveneto as a single homogeneous region and developed a regional model using annual maximum series (AMS) of peak discharges that were collected up to the 1980s by the former Italian Hydrometeorological Service. We consider a very detailed AMS database that we recently compiled for 76 catchments located in Triveneto. All 76 study catchments are characterized in terms of several geomorphologic and climatic descriptors. The objective of our study is threefold: (1) to inspect climatic and scale controls on flood frequency regime; (2) to verify the possible presence of changes in flood frequency regime by looking at changes in time of regional L-moments of annual maximum floods; (3) to develop an updated reference procedure for design flood estimation in Triveneto by using a focused-pooling approach (i.e. Region of Influence, RoI). Our study leads to the following conclusions: (1) climatic and scale controls on flood frequency regime in Triveneto are similar to the controls that were recently found in Europe; (2) a single year characterized by extreme floods can have a remarkable influence on regional flood frequency models and analyses for detecting possible changes in flood frequency regime; (3) no significant change was detected in the flood frequency regime, yet an update of the existing reference procedure for design flood estimation is highly recommended and we propose the RoI approach for properly representing climate and scale controls on flood frequency in Triveneto, which cannot be regarded as a single homogeneous region.

Characterization of floods in the United States

NASA Astrophysics Data System (ADS)

Saharia, Manabendra; Kirstetter, Pierre-Emmanuel; Vergara, Humberto; Gourley, Jonathan J.; Hong, Yang

2017-05-01

Floods have gained increasing global significance in the recent past due to their devastating nature and potential for causing significant economic and human losses. Until now, flood characterization studies in the United States have been limited due to the lack of a comprehensive database matching flood characteristics such as peak discharges and flood duration with geospatial and geomorphologic information. The availability of a representative and long archive of flooding events spanning 78 years over a variety of hydroclimatic regions results in a spatially and temporally comprehensive flood characterization over the continental U.S. This study, for the first time, employs a large-event database that is based on actual National Weather Service (NWS) definitions of floods instead of the frequently-adopted case study or frequentist approach, allowing us to base our findings on real definitions of floods. It examines flooding characteristics to identify how space and time scales of floods vary with climatic regimes and geomorphology. Flood events were characterized by linking flood response variables in gauged basins to spatially distributed variables describing climatology, geomorphology, and topography. The primary findings of this study are that the magnitude of flooding is highest is regions such as West Coast and southeastern U.S. which experience the most extraordinary precipitation. The seasonality of flooding varies greatly from maxima during the cool season on the West Coast, warm season in the desert Southwest, and early spring in the Southeast. The fastest responding events tend to be in steep basins of the arid Southwest caused by intense monsoon thunderstorms and steep terrain. The envelope curves of unit peak discharge are consistent with those reported for Europe and worldwide. But significant seasonal variability was observed in floods of the U.S. compared to Europe that is attributed to the diversity of causative rainfall ranging from synoptic scales with orographic enhancements in the West Coast, monsoon thunderstorms in the desert Southwest, to land-falling tropical storms and localized, intense thunderstorms in the Southeast.

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

NASA Astrophysics Data System (ADS)

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 risk statistical characterization, the proposed procedure could be applied straightforward outside the national borders, particularly in areas with similar geo-environmental settings.

Changing flood frequencies under opposing late Pleistocene eastern Mediterranean climates.

PubMed

Ben Dor, Yoav; Armon, Moshe; Ahlborn, Marieke; Morin, Efrat; Erel, Yigal; Brauer, Achim; Schwab, Markus Julius; Tjallingii, Rik; Enzel, Yehouda

2018-05-31

Floods comprise a dominant hydroclimatic phenomenon in aridlands with significant implications for humans, infrastructure, and landscape evolution worldwide. The study of short-term hydroclimatic variability, such as floods, and its forecasting for episodes of changing climate therefore poses a dominant challenge for the scientific community, and predominantly relies on modeling. Testing the capabilities of climate models to properly describe past and forecast future short-term hydroclimatic phenomena such as floods requires verification against suitable geological archives. However, determining flood frequency during changing climate is rarely achieved, because modern and paleoflood records, especially in arid regions, are often too short or discontinuous. Thus, coeval independent climate reconstructions and paleoflood records are required to further understand the impact of climate change on flood generation. Dead Sea lake levels reflect the mean centennial-millennial hydrological budget in the eastern Mediterranean. In contrast, floods in the large watersheds draining directly into the Dead Sea, are linked to short-term synoptic circulation patterns reflecting hydroclimatic variability. These two very different records are combined in this study to resolve flood frequency during opposing mean climates. Two 700-year-long, seasonally-resolved flood time series constructed from late Pleistocene Dead Sea varved sediments, coeval with significant Dead Sea lake level variations are reported. These series demonstrate that episodes of rising lake levels are characterized by higher frequency of floods, shorter intervals between years of multiple floods, and asignificantly larger number of years that experienced multiple floods. In addition, floods cluster into intervals of intense flooding, characterized by 75% and 20% increased frequency above their respective background frequencies during rising and falling lake-levels, respectively. Mean centennial precipitation in the eastern Mediterranean is therefore coupled with drastic changes in flood frequencies. These drastic changes in flood frequencies are linked to changes in the track, depth, and frequency of mid-latitude eastern Mediterranean cyclones, determining mean climatology resulting in wetter and drier regional climatic episodes.

78 FR 29760 - Final Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-21

... accordance with section 110 of the Flood Disaster Protection Act of 1973, 42 U.S.C. 4104, and 44 CFR part 67...] Final Flood Hazard Determinations AGENCY: Federal Emergency Management Agency, DHS. ACTION: Final Notice. SUMMARY: Flood hazard determinations, which may include additions or modifications of Base Flood...

How Can Flood Affect the Real Estate Market?

NASA Astrophysics Data System (ADS)

Trejo Rangel, Miguel Angel; Sapač, Klaudija; Brilly, Mitja

2016-04-01

The purpose of this paper is to examine how actual flood events can affect the real estate for different case studies. Therefore, we have analysed the impact for two cases, the first is the flood event which occurred in 2013 in Boulder, Colorado, United States, city that is located in the eastern part of the Rocky Mountains, and the second event was the flood which occurred in 2010 the city of Ljubljana, capital and largest city of Slovenia, that is located between the Alpine and Balkan mountains.. The methodology that was used is comparison of mean prices of real estate, taking into account the flood events which have been chosen in accordance with the available data and previous studies, furthermore for the case study of Ljubljana, Slovenia questionnaires were sent through one civil organization which is actively working in the area (Civil Initiative for Flood Security SW part of Ljubljana). Analysed sales prices during the period 2009-2014 in the case study of Boulder, Colorado, United States showed that the flood event in 2013 did not significantly affect the mean price of real estate within the flooded area, besides prices inside the flood plain tended to stay above the prices outside the floodplain. Nevertheless, we have found that the flood event affected the real estate sector in terms of number of sales, being that after the flood event in 2013 sales decreased 52% regarding the previous years. For the case study of Ljubljana, Slovenia the results were unexpected somehow. In fact we expected that the prices of real estate located within the flooded areas, on average, would be lower than those located outside the flooded areas, and that was what shown in the results, which is actually opposite to what occurred for the case study of Boulder City. However the research showed that the flood event in 2010 did not affect the change in prices of real estate within the flooded areas and the trend was considerable similar to previous years the flood event in 2010, where property prices within the flooded area were during the whole period for approximately 10.6% lower than those outside the flooded area. This shows that there is a constant influence of the flood-prone area which is also confirm by the respondents of the questionnaires which were sent, however they tended to underestimate even more the actual value of the properties inside this area almost half the price of a similar property outside the flood-prone area.

The flood of 2011 in the lower Chao Phraya valley, Thailand: Study of a long-duration flood through satellite images

NASA Astrophysics Data System (ADS)

Liew, Soo Chin; Gupta, Avijit; Chia, Aik Song; Ang, Wu Chye

2016-06-01

The paper illustrates application of satellite images for studying the anatomy of a long-duration, extensive, and slow flood on the Chao Phraya River in 2011 that inundated Bangkok in its lower reach. The spread of floods in the valley was mapped with MODIS, month by month, from July 2011 to February 2012. A subsampled WorldView-2 mosaic was used to observe part of the valley in detail. The flood in Bangkok was studied with four higher-resolution images from Spot 4, WorldView-2, and GeoEye-1 satellites. We suspect that the floodwaters jumped the banks of the Chao Phraya south of Chai Nat, and then travelled overland and along river channels. The overland passage made it difficult to protect settlements. We also studied sedimentation from the images of this shallow overland flow across the country, which was complicated by the presence of preexisting embankments, other anthropogenic structures, and smaller stream channels. This is a descriptive study but it highlights the nature of flooding that is likely to be repeated in this low flat valley from high rainfall. The pattern of flooding was similar to that of a previous large flood in 1996 recorded in a SPOT 2 image. These floods impact Bangkok periodically, a city of about 10 million people, which started on a levee in a low flat delta, then expanded into backswamps, and is marked with local depressions from groundwater extraction. These slow extensive floods can be mapped from satellite images and properly recorded as an early step in analysis of large floods. Mapping of such floods on ground is logistically impossible. Slow, extensive, and long-lasting floods affect lower valleys and deltas of a number of major rivers, impacting agricultural fields and large populations. These floods are especially disastrous for cities located on low deltas. We submit that basic exercises on satellite images provide valuable introductory information for understanding geomorphology of such floods, and also for structuring plans for flood amelioration. Satellite images at very high resolutions, also used in this study, provide complimentary data to mapping and ground observation. Basin environments that are inundated by large shallow extensive floods are not unusual. In future, climate change is expected to raise the frequency of floods in lower parts of a number of river valleys and deltas, so that for such an environment slow extensive floods may become common and need to be studied. In that sense this is a template for studying large slow floods, arguably more frequent in future.

Establishment and Practical Application of Flood Warning Stage in Taiwan's River

NASA Astrophysics Data System (ADS)

Yang, Sheng-Hsueh; Chia Yeh, Keh-

2017-04-01

In the face of extreme flood events or the possible impact of climate change, non-engineering disaster prevention and early warning work is particularly important. Taiwan is an island topography with more than 3,900 meters of high mountains. The length of the river is less than 100 kilometers. Most of the watershed catchment time is less than 24 hours, which belongs to the river with steep slope and rapid flood. Every year in summer and autumn, several typhoon events invade Taiwan. Typhoons often result in rainfall events in excess of 100 mm/hr or 250 mm/3hr. In the face of Taiwan's terrain and extreme rainfall events, flooding is difficult to avoid. Therefore, most of the river has embankment protection, so that people do not have to face every year flooding caused by economic and life and property losses. However, the river embankment protection is limited. With the increase of the hydrological data, the design criteria for the embankment protection standards in the past was 100 year of flood return period and is now gradually reduced to 25 or 50 year of flood return period. The river authorities are not easy to rise the existing embankment height. The safety of the river embankment in Taiwan is determined by the establishment of the flood warning stage to cope with the possible increase in annual floods and the impact of extreme hydrological events. The flood warning stage is equal to the flood control elevation minus the flood rise rate multiply by the flood early warning time. The control elevation can be the top of the embankment, the design flood level of the river, the embankment gap of the river section, the height of the bridge beam bottom, etc. The flood rise rate is consider the factors such as hydrological stochastic and uncertain rainfall and the effect of flood discharge operation on the flood in the watershed catchment area. The maximum value of the water level difference between the two hours or five hours before the peak value of the analysis result is decided by this rate. The flood early warning time is divided into two levels, the first level is 2 hours, evacuation time for the public, the second level is 5 hours for the implementation of unit preparation time. Finally, The flood warning stages are practical application in 20 water level stations have been incorporated into the flood early warning system of the Danshuei river basin in Taiwan.

46 CFR 62.35-10 - Flooding safety.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Flooding safety. 62.35-10 Section 62.35-10 Shipping... Requirements for Specific Types of Automated Vital Systems § 62.35-10 Flooding safety. (a) Automatic bilge.... (b) Remote controls for flooding safety equipment must remain functional under flooding conditions to...

46 CFR 62.35-10 - Flooding safety.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Flooding safety. 62.35-10 Section 62.35-10 Shipping... Requirements for Specific Types of Automated Vital Systems § 62.35-10 Flooding safety. (a) Automatic bilge.... (b) Remote controls for flooding safety equipment must remain functional under flooding conditions to...

46 CFR 62.35-10 - Flooding safety.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Flooding safety. 62.35-10 Section 62.35-10 Shipping... Requirements for Specific Types of Automated Vital Systems § 62.35-10 Flooding safety. (a) Automatic bilge.... (b) Remote controls for flooding safety equipment must remain functional under flooding conditions to...

44 CFR 64.3 - Flood Insurance Maps.

Code of Federal Regulations, 2012 CFR

2012-10-01

... tidal floods (coastal high hazard area) V1-30, VE Area of special flood hazards, with water surface elevations determined and with velocity, that is inundated by tidal floods (coastal high hazard area) V0 Area..., but possible, mudslide hazards E Area of special flood-related erosion hazards. Areas identified as...

44 CFR 64.3 - Flood Insurance Maps.

Code of Federal Regulations, 2013 CFR

2013-10-01

... tidal floods (coastal high hazard area) V1-30, VE Area of special flood hazards, with water surface elevations determined and with velocity, that is inundated by tidal floods (coastal high hazard area) V0 Area..., but possible, mudslide hazards E Area of special flood-related erosion hazards. Areas identified as...

44 CFR 64.3 - Flood Insurance Maps.

Code of Federal Regulations, 2014 CFR

2014-10-01

... tidal floods (coastal high hazard area) V1-30, VE Area of special flood hazards, with water surface elevations determined and with velocity, that is inundated by tidal floods (coastal high hazard area) V0 Area..., but possible, mudslide hazards E Area of special flood-related erosion hazards. Areas identified as...

46 CFR 62.35-10 - Flooding safety.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Flooding safety. 62.35-10 Section 62.35-10 Shipping... Requirements for Specific Types of Automated Vital Systems § 62.35-10 Flooding safety. (a) Automatic bilge.... (b) Remote controls for flooding safety equipment must remain functional under flooding conditions to...

44 CFR 206.252 - Insurance requirements for facilities damaged by flood.

Code of Federal Regulations, 2010 CFR

2010-10-01

... facilities damaged by flood. 206.252 Section 206.252 Emergency Management and Assistance FEDERAL EMERGENCY... Assistance Insurance Requirements § 206.252 Insurance requirements for facilities damaged by flood. (a) Where an insurable building damaged by flooding is located in a special flood hazard area identified for...

44 CFR 73.4 - Restoration of flood insurance coverage.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Restoration of flood... AGENCY, DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program IMPLEMENTATION OF SECTION 1316 OF THE NATIONAL FLOOD INSURANCE ACT OF 1968 § 73.4 Restoration of flood insurance...

7 CFR 650.25 - Flood-plain management.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 6 2010-01-01 2010-01-01 false Flood-plain management. 650.25 Section 650.25... Flood-plain management. Through proper planning, flood plains can be managed to reduce the threat to... encourages sound flood-plain management decisions by land users. (a) Policy—(1) General. NRCS provides...

Safety in the Chemical Laboratory: Flood Control.

ERIC Educational Resources Information Center

Pollard, Bruce D.

1983-01-01

Describes events leading to a flood in the Wehr Chemistry Laboratory at Marquette University, discussing steps taken to minimize damage upon discovery. Analyzes the problem of flooding in the chemical laboratory and outlines seven steps of flood control: prevention; minimization; early detection; stopping the flood; evaluation; clean-up; and…

Floods in the Wapsipinicon River Basin, Iowa

USGS Publications Warehouse

Schwob, Harlan H.

1971-01-01

Flood-profile sheets show profiles of actual flood occurrences and computed profiles of the 25- and 50-year floods at most locations. These sheets also contain tabulations of the flood discharges profiled. A low-water profile and tabulated discharge indicate the range in elevation and discharge along the streams.

Nutrient response of Bacopa monnieri (water hyssop) to varying degrees of soil saturation

USDA-ARS?s Scientific Manuscript database

Tissue concentrations of N and P were measured in Bacopa monnieri subjected to four progressive levels of flooding: well-drained Control, Intermittently Flooded, Partially Flooded, and Continuously Flooded. Soil redox potential (Eh) decreased in all flooded treatments at 30 cm depth, becoming anoxic...

44 CFR 9.7 - Determination of proposed action's location.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Regional Administrator shall consult the FEMA Flood Insurance Rate Map (FIRM) the Flood Boundary Floodway Map (FBFM) and the Flood Insurance Study (FIS). (ii) If a detailed map (FIRM or FBFM) is not available, the Regional Administrator shall consult an FEMA Flood Hazard Boundary Map (FHBM) . If data on flood...

Root traits of a soybean (Glycinemax) recombinant inbred population segregating for flooding tolerance.

USDA-ARS?s Scientific Manuscript database

Soybeans (Glycine max) are known to be sensitive to flooding stress. Flooding at the reproductive stage can reduce soybean yield by 50%. However, recent screening efforts have resulted in the identification of genotypes differing in susceptibility to flooding. The flooding tolerant genotype PI 40810...

Flooding and Schools

ERIC Educational Resources Information Center

National Clearinghouse for Educational Facilities, 2011

2011-01-01

According to the Federal Emergency Management Agency, flooding is the nation's most common natural disaster. Some floods develop slowly during an extended period of rain or in a warming trend following a heavy snow. Flash floods can occur quickly, without any visible sign of rain. Catastrophic floods are associated with burst dams and levees,…

46 CFR 62.35-10 - Flooding safety.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Flooding safety. 62.35-10 Section 62.35-10 Shipping... Requirements for Specific Types of Automated Vital Systems § 62.35-10 Flooding safety. (a) Automatic bilge.... (b) Remote controls for flooding safety equipment must remain functional under flooding conditions to...

7 CFR 650.25 - Flood-plain management.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 6 2011-01-01 2011-01-01 false Flood-plain management. 650.25 Section 650.25... Flood-plain management. Through proper planning, flood plains can be managed to reduce the threat to... encourages sound flood-plain management decisions by land users. (a) Policy—(1) General. NRCS provides...

Magnitude and frequency of floods in Nebraska

USGS Publications Warehouse

Beckman, Emil W.

1976-01-01

Observed maximum flood peaks at 303 gaging stations with 13 or more years of record and significant peaks at 57 short-term stations and 31 miscellaneous sites are useful in designing flood-control works for maximum safety from flood damage. Comparison is made with maximum observed floods in the United States.

44 CFR 61.5 - Special terms and conditions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.5 Special terms and conditions. (a) No new flood insurance or renewal of flood... other authority to be in violation of any flood plain, mudslide (i.e., mudflow) or flood-related erosion...

44 CFR 61.17 - Group Flood Insurance Policy.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.17 Group Flood Insurance Policy. (a) A Group Flood Insurance Policy (GFIP) is a... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Group Flood Insurance Policy...

44 CFR 61.17 - Group Flood Insurance Policy.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.17 Group Flood Insurance Policy. (a) A Group Flood Insurance Policy (GFIP) is a... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Group Flood Insurance Policy...

44 CFR 67.3 - Establishment and maintenance of a flood elevation determination docket (FEDD).

Code of Federal Regulations, 2014 CFR

2014-10-01

... MITIGATION National Flood Insurance Program APPEALS FROM PROPOSED FLOOD ELEVATION DETERMINATIONS § 67.3 Establishment and maintenance of a flood elevation determination docket (FEDD). The Federal Insurance... of a flood elevation determination docket (FEDD). 67.3 Section 67.3 Emergency Management and...

44 CFR 67.3 - Establishment and maintenance of a flood elevation determination docket (FEDD).

Code of Federal Regulations, 2012 CFR

2012-10-01

... MITIGATION National Flood Insurance Program APPEALS FROM PROPOSED FLOOD ELEVATION DETERMINATIONS § 67.3 Establishment and maintenance of a flood elevation determination docket (FEDD). The Federal Insurance... of a flood elevation determination docket (FEDD). 67.3 Section 67.3 Emergency Management and...

44 CFR 73.3 - Denial of flood insurance coverage.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program IMPLEMENTATION OF SECTION 1316 OF THE NATIONAL FLOOD INSURANCE ACT OF 1968 § 73.3 Denial of flood insurance... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Denial of flood insurance...

44 CFR 61.17 - Group Flood Insurance Policy.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.17 Group Flood Insurance Policy. (a) A Group Flood Insurance Policy (GFIP) is a... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Group Flood Insurance Policy...

44 CFR 61.17 - Group Flood Insurance Policy.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.17 Group Flood Insurance Policy. (a) A Group Flood Insurance Policy (GFIP) is a... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Group Flood Insurance Policy...

44 CFR 61.17 - Group Flood Insurance Policy.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.17 Group Flood Insurance Policy. (a) A Group Flood Insurance Policy (GFIP) is a... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Group Flood Insurance Policy...

44 CFR 73.4 - Restoration of flood insurance coverage.

Code of Federal Regulations, 2014 CFR

2014-10-01

... AGENCY, DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program IMPLEMENTATION OF SECTION 1316 OF THE NATIONAL FLOOD INSURANCE ACT OF 1968 § 73.4 Restoration of flood insurance... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Restoration of flood...

44 CFR 61.5 - Special terms and conditions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.5 Special terms and conditions. (a) No new flood insurance or renewal of flood... other authority to be in violation of any flood plain, mudslide (i.e., mudflow) or flood-related erosion...

44 CFR 73.3 - Denial of flood insurance coverage.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program IMPLEMENTATION OF SECTION 1316 OF THE NATIONAL FLOOD INSURANCE ACT OF 1968 § 73.3 Denial of flood insurance... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Denial of flood insurance...

44 CFR 61.5 - Special terms and conditions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program INSURANCE COVERAGE AND RATES § 61.5 Special terms and conditions. (a) No new flood insurance or renewal of flood... other authority to be in violation of any flood plain, mudslide (i.e., mudflow) or flood-related erosion...

44 CFR 73.4 - Restoration of flood insurance coverage.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF HOMELAND SECURITY INSURANCE AND HAZARD MITIGATION National Flood Insurance Program IMPLEMENTATION OF SECTION 1316 OF THE NATIONAL FLOOD INSURANCE ACT OF 1968 § 73.4 Restoration of flood insurance... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Restoration of flood insurance...

The "Prediflood" database of historical floods in Catalonia (NE Iberian Peninsula) AD 1035-2013, and its potential applications in flood analysis

NASA Astrophysics Data System (ADS)

Barriendos, M.; Ruiz-Bellet, J. L.; Tuset, J.; Mazón, J.; Balasch, J. C.; Pino, D.; Ayala, J. L.

2014-07-01

"Prediflood" is a database of historical floods occurred in Catalonia (NE Iberian Peninsula), between 10th Century and 21th Century. More than 2700 flood cases are catalogued, and more than 1100 flood events. This database contains information acquired under modern historiographical criteria and it is, therefore, apt to be used in multidisciplinary flood analysis techniques, as meteorological or hydraullic reconstructions.

Digital technologies in support of flood resilience: A case study from Nepal

NASA Astrophysics Data System (ADS)

Liu, Wei; McCallum, Ian; See, Linda; Dugar, Sumit; Laso-Bayas, Juan-Carlos

2016-04-01

This paper presents ongoing efforts to support flood resilience in the Karnali basin in Nepal through the provision of different forms of digital technology. Flood Risk Geo-Wiki is an online visualization and crowdsourcing tool, which has been adapted to display flood risk maps at the global scale as well as information of relevance to planners and the community at the local level. Community-based flood risk maps, which have traditionally been drawn on paper, are being digitized and integrated with OpenStreetMap to provide better access to this collective knowledge base. Mobile phones, using the GeoODK (Geographical Open Data Kit) questionnaire builder, are being deployed to collect georeferenced information on flood risks and vulnerability, which can be used to validate flood models and design action plans and strategies for coping with future flood events. These types of digital technologies are simple to implement yet together can help support flood prone communities.

Winter water; the flooding at Boise, Idaho, January 11-12, 1979

USGS Publications Warehouse

Harper, Robert William; Hubbard, E.F.

1980-01-01

On January 11 and 12, 1979, unseasonally warm temperatures and rain on several inches of snow lying on frozen ground caused widespread flooding in and around Boise, Idaho. Streams north of Boise crested on January 11, flooding neighborhoods in and adjacent to the mountain foothills. On January 12, streams south and west of the city reached their highest stages. Flooding was confined to ground levels and basements of homes and businesses in low-lying areas. The U.S. Geological Survey made indirect measurements of peak dicharges at selected sites on streams that had the worst flooding. The peak discharges were relatively low in comparison with data from historic floods. Much more severe flooding than this event is likely to occur in the future. More data are needed on the occurrence of flooding in Boise Valley to aid in flood-protection planning. (USGS)

Flood-inundation maps and updated components for a flood-warning system or the City of Marietta, Ohio and selected communities along the Lower Muskingum River and Ohio River

USGS Publications Warehouse

Whitehead, Matthew T.; Ostheimer, Chad J.

2014-01-01

Flood profiles for selected reaches were prepared by calibrating steady-state step-backwater models to selected streamgage rating curves. The step-backwater models were used to determine water-surface-elevation profiles for up to 12 flood stages at a streamgage with corresponding stream-flows ranging from approximately the 10- to 0.2-percent chance annual-exceedance probabilities for each of the 3 streamgages that correspond to the flood-inundation maps. Additional hydraulic modeling was used to account for the effects of backwater from the Ohio River on water levels in the Muskingum River. The computed longitudinal profiles of flood levels were used with a Geographic Information System digital elevation model (derived from light detection and ranging) to delineate flood-inundation areas. Digital maps showing flood-inundation areas overlain on digital orthophotographs were prepared for the selected floods.

Cane Creek flood-flow characteristics at State Route 30 near Spencer, Tennessee

USGS Publications Warehouse

Gamble, Charles R.

1983-01-01

The Tennessee Department of Transportation has constructed a new bridge and approaches on State Route 30 over Cane Creek near Spencer, Tennessee. The old bridge and its approaches were fairly low, permitting considerable flow over the road during high floods. The new bridge and its approaches are considerably higher, causing different flow conditions at the site. Analysis of the effects of the new bridge, as compared to the old bridge, on floods of the magnitude of the May 27, 1973, flood is presented. The May 27, 1973, flood was greater than a 100-year flood. Analysis of the 50- and 100-year floods for the new bridge are also presented. Results of the study indicate that the new construction will increase the water-surface elevation for a flood equal to the May 27, 1973, flood by approximately 1 foot upstream from bridge. (USGS)

The role of interactions along the flood process chain and implications for risk assessment

NASA Astrophysics Data System (ADS)

Vorogushyn, Sergiy; Apel, Heiko; Viet Nguyen, Dung; Guse, Björn; Kreibich, Heidi; Lüdtke, Stefan; Schröter, Kai; Merz, Bruno

2017-04-01

Floods with their manifold characteristics are shaped by various processes along the flood process chain - from triggering meteorological extremes through catchment and river network process down to impacts on societies. In flood risk systems numerous interactions and feedbacks along the process chain may occur which finally shape spatio-temporal flood patterns and determine the ultimate risk. In this talk, we review some important interactions in the atmosphere-catchment, river-dike-floodplain and vulnerability compartments of the flood risk system. We highlight the importance of spatial interactions for flood hazard and risk assessment. For instance, the role of spatial rainfall structure or wave superposition in river networks is elucidated with selected case studies. In conclusion, we show the limits of current methods in assessment of large-scale flooding and outline the approach to more comprehensive risk assessment based on our regional flood risk model (RFM) for Germany.

Methods for Estimating Magnitude and Frequency of Floods in Rural Basins in the Southeastern United States: South Carolina

USGS Publications Warehouse

Feaster, Toby D.; Gotvald, Anthony J.; Weaver, J. Curtis

2009-01-01

For more than 50 years, the U.S. Geological Survey (USGS) has been developing regional regression equations that can be used to estimate flood magnitude and frequency at ungaged sites. Flood magnitude relates to the volume of flow that occurs over some period of time and usually is presented in cubic feet per second. Flood frequency relates to the probability of occurrence of a flood; that is, on average, what is the likelihood that a flood with a specified magnitude will occur in any given year (1 percent chance, 10 percent chance, 50 percent chance, and so on). Such flood estimates are needed for the efficient design of bridges, highway embankments, levees, and other structures near streams. In addition, these estimates are needed for the effective planning and management of land and water resources, to protect lives and property in flood-prone areas, and to determine flood-insurance rates.

Microbial and chemical contamination during and after flooding in the Ohio River-Kentucky, 2011.

PubMed

Yard, Ellen E; Murphy, Matthew W; Schneeberger, Chandra; Narayanan, Jothikumar; Hoo, Elizabeth; Freiman, Alexander; Lewis, Lauren S; Hill, Vincent R

2014-09-19

Surface water contaminants in Kentucky during and after 2011 flooding were characterized. Surface water samples were collected during flood stage (May 2-4, 2011; n = 15) and after (July 25-26, 2011; n = 8) from four different cities along the Ohio River and were analyzed for the presence of microbial indicators, pathogens, metals, and chemical contaminants. Contaminant concentrations during and after flooding were compared using linear and logistic regression. Surface water samples collected during flooding had higher levels of E. coli, enterococci, Salmonella, Campylobacter, E. coli O157:H7, adenovirus, arsenic, copper, iron, lead, and zinc compared to surface water samples collected 3-months post-flood (P < 0.05). These results suggest that flooding increases microbial and chemical loads in surface water. These findings reinforce commonly recommended guidelines to limit exposure to flood water and to appropriately sanitize contaminated surfaces and drinking wells after contamination by flood water.

Microbial and chemical contamination during and after flooding in the Ohio River—Kentucky, 2011

PubMed Central

Yard, Ellen E.; Murphy, Matthew W.; Schneeberger, Chandra; Narayanan, Jothikumar; Hoo, Elizabeth; Freiman, Alexander; Lewis, Lauren S.; Hill, Vincent R.

2017-01-01

Surface water contaminants in Kentucky during and after 2011 flooding were characterized. Surface water samples were collected during flood stage (May 2–4, 2011; n = 15) and after (July 25–26, 2011; n = 8) from four different cities along the Ohio River and were analyzed for the presence of microbial indicators, pathogens, metals, and chemical contaminants. Contaminant concentrations during and after flooding were compared using linear and logistic regression. Surface water samples collected during flooding had higher levels of E. coli, enterococci, Salmonella, Campylobacter, E. coli O157:H7, adenovirus, arsenic, copper, iron, lead, and zinc compared to surface water samples collected 3-months post-flood (P < 0.05). These results suggest that flooding increases microbial and chemical loads in surface water. These findings reinforce commonly recommended guidelines to limit exposure to flood water and to appropriately sanitize contaminated surfaces and drinking wells after contamination by flood water. PMID:24967556

Changing climate shifts timing of European floods.

PubMed

Blöschl, Günter; Hall, Julia; Parajka, Juraj; Perdigão, Rui A P; Merz, Bruno; Arheimer, Berit; Aronica, Giuseppe T; Bilibashi, Ardian; Bonacci, Ognjen; Borga, Marco; Čanjevac, Ivan; Castellarin, Attilio; Chirico, Giovanni B; Claps, Pierluigi; Fiala, Károly; Frolova, Natalia; Gorbachova, Liudmyla; Gül, Ali; Hannaford, Jamie; Harrigan, Shaun; Kireeva, Maria; Kiss, Andrea; Kjeldsen, Thomas R; Kohnová, Silvia; Koskela, Jarkko J; Ledvinka, Ondrej; Macdonald, Neil; Mavrova-Guirguinova, Maria; Mediero, Luis; Merz, Ralf; Molnar, Peter; Montanari, Alberto; Murphy, Conor; Osuch, Marzena; Ovcharuk, Valeryia; Radevski, Ivan; Rogger, Magdalena; Salinas, José L; Sauquet, Eric; Šraj, Mojca; Szolgay, Jan; Viglione, Alberto; Volpi, Elena; Wilson, Donna; Zaimi, Klodian; Živković, Nenad

2017-08-11

A warming climate is expected to have an impact on the magnitude and timing of river floods; however, no consistent large-scale climate change signal in observed flood magnitudes has been identified so far. We analyzed the timing of river floods in Europe over the past five decades, using a pan-European database from 4262 observational hydrometric stations, and found clear patterns of change in flood timing. Warmer temperatures have led to earlier spring snowmelt floods throughout northeastern Europe; delayed winter storms associated with polar warming have led to later winter floods around the North Sea and some sectors of the Mediterranean coast; and earlier soil moisture maxima have led to earlier winter floods in western Europe. Our results highlight the existence of a clear climate signal in flood observations at the continental scale. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Flood risk governance arrangements in Europe

NASA Astrophysics Data System (ADS)

Matczak, P.; Lewandowski, J.; Choryński, A.; Szwed, M.; Kundzewicz, Z. W.

2015-06-01

The STAR-FLOOD (Strengthening and Redesigning European Flood Risk Practices Towards Appropriate and Resilient Flood Risk Governance Arrangements) project, funded by the European Commission, investigates strategies for dealing with flood risk in six European countries: Belgium, the UK, France, the Netherlands, Poland and Sweden and in 18 vulnerable urban regions in these countries. The project aims to describe, analyse, explain, and evaluate the main similarities and differences between the selected EU Member States in terms of development and performance of flood risk governance arrangements. It also discusses the scientific and societal importance of these similarities and differences. Attention is paid to identification and characterization of shifts in flood risk governance arrangements and in flood risk management strategies and to determination of triggering factors and restraining factors. An assessment of a change of resilience and appropriateness (legitimacy, effectiveness, efficiency) of flood risk governance arrangements in Poland is presented and comparison with other European countries is offered.

Beyond the Floodplain: Drivers of Flood Risk in Coastal Cities

NASA Astrophysics Data System (ADS)

Rosenzweig, B.; McPhearson, T.; Rosi, E. J.

2017-12-01

While the catastrophic impacts of Hurricane Katrina increased awareness of coastal flood risk, conventional approaches to flood risk assessment do not adequately represent the drivers of flood risk in the unique, highly engineered landscape of dense cities. We review the recent (1996-2016) history of flooding events and current regional climate change projection for 4 diverse coastal cities in the United States: San Juan, Miami, Baltimore and New York. Our review suggests that while all 4 of these cities face increased risk from direct coastal flooding with climate change, pluvial flooding will be an additional, important driver of risk that is currently poorly quantified. Unlike other types of flooding, pluvial flood risk is not limited to a contiguous riverine or coastal floodplain, but is instead driven by interactions between spatially variable geophysical drivers (intense rainfall, shallow groundwater, and influent tidal water), social drivers (patterns of land use) and technical drivers (urban stormwater and coastal infrastructure). We discuss approaches for quantitative assessment of pluvial flood risk, the challenges presented by the lack of data on geophysical flooding drivers in dense cities, and opportunities for integrated research to provide the scientific information needed by practitioners.

Analyses of flooding tolerance of soybean varieties at emergence and varietal differences in their proteomes.

PubMed

Nanjo, Yohei; Jang, Hee-Young; Kim, Hong-Sig; Hiraga, Susumu; Woo, Sun-Hee; Komatsu, Setsuko

2014-10-01

Flooding of fields due to heavy and/or continuous rainfall influences soybean production. To identify soybean varieties with flooding tolerance at the seedling emergence stage, 128 soybean varieties were evaluated using a flooding tolerance index, which is based on plant survival rates, the lack of apparent damage and lateral root development, and post-flooding radicle elongation rate. The soybean varieties were ranked according to their flooding tolerance index, and it was found that the tolerance levels of soybean varieties exhibit a continuum of differences between varieties. Subsequently, tolerant, moderately tolerant and sensitive varieties were selected and subjected to comparative proteomic analysis to clarify the tolerance mechanism. Proteomic analysis of the radicles, combined with correlation analysis, showed that the ratios of RNA binding/processing related proteins and flooding stress indicator proteins were significantly correlated with flooding tolerance index. The RNA binding/processing related proteins were positively correlated in untreated soybeans, whereas flooding stress indicator proteins were negatively correlated in flooded soybeans. These results suggest that flooding tolerance is regulated by mechanisms through multiple factors and is associated with abundance levels of the identified proteins. Copyright © 2014 Elsevier Ltd. All rights reserved.

Flood-inundation map and water-surface profiles for floods of selected recurrence intervals, Consumnes River and Deer Creek, Sacramento County, California

USGS Publications Warehouse

Guay, Joel R.; Harmon, Jerry G.; McPherson, Kelly R.

1998-01-01

The damage caused by the January 1997 floods along the Cosumnes River and Deer Creek generated new interest in planning and managing land use in the study area. The 1997 floodflow peak, the highest on record and considered to be a 150-year flood, caused levee failures at 24 locations. In order to provide a technical basis for floodplain management practices, the U.S. Goelogical Survey, in cooperation with the Federal Emergency Management Agency, completed a flood-inundation map of the Cosumnes River and Deer Creek drainage from Dillard Road bridge to State Highway 99. Flood frequency was estimated from streamflow records for the Cosumnes River at Michigan Bar and Deer Creek near Sloughhouse. Cross sections along a study reach, where the two rivers generally flow parallel to one another, were used with a step-backwater model (WSPRO) to estimate the water-surface profile for floods of selected recurrence intervals. A flood-inundation map was developed to show flood boundaries for the 100-year flood. Water-surface profiles were developed for the 5-, 10-, 50-, 100-, and 500-year floods.

Evaluation of the flood hydrology in the Colorado Front Range using precipitation, streamflow, and paleoflood data for the Big Thompson River basin

USGS Publications Warehouse

Jarrett, R.D.; Costa, J.E.

1988-01-01

A multidisciplinary study of precipitation and streamflow data and paleohydrologic studies of channel features was made to analyze the flood hydrology of foothill and mountain streams in the Front Range of Colorado, with emphasis on the Big Thompson River basin, because conventional hydrologic analyses do not adequately characterize the flood hydrology. In the foothills of Colorado, annual floodflows are derived from snowmelt at high elevations in the mountain regions, from rainfall at low elevation in the plains or plateau regions, or from a combination of rain falling on snow or mixed population hydrology. Above approximately 7,500 ft, snowmelt dominates; rain does not contribute to the flood potential. Regional flood-frequency relations were developed and compared with conventional flood-estimating technique results, including an evaluation of the magnitude and frequency of the probable maximum flood. Evaluation of streamflow data and paleoflood investigations provide an alternative for evaluating flood hydrology and the safety of dams. The study indicates the need for additional data collection and research to understand the complexities of the flood hydrology in mountainous regions, especially its effects on flood-plain management and the design of structures in the flood plain. (USGS)

Response of plant productivity to experimental flooding in a stable and a submerging marsh

USGS Publications Warehouse

Kirwan, Matthew L.; Guntenspergen, Glenn R.

2015-01-01

Recent models of tidal marsh evolution rely largely on the premise that plants are most productive at an optimal flooding regime that occurs when soil elevations are somewhere between mean sea level and mean high tide. Here, we use 4 years of manipulative “marsh organ” flooding experiments to test the generality of this conceptual framework and to examine how the optimal flooding frequency may change between years and locations. In our experiments, above and belowground growth of Schoenoplectus americanus was most rapid when flooded about 40% of the time in a rapidly submerging marsh and when flooded about 25% of the time in a historically stable marsh. Optimum flooding durations were nearly identical in each year of the experiment and did not differ for above and belowground growth. In contrast, above and belowground growth of Spartina patensdecreased monotonically with increased flooding in all years and at both sites, indicating no optimal flooding frequency or elevation relative to sea level. Growth patterns in both species suggest a wider tolerance to flooding, and greater biomass for a given flooding duration, in the rapidly deteriorating marsh.

How Flood Experience and Risk Perception Influences Protective Actions and Behaviours among Canadian Homeowners

NASA Astrophysics Data System (ADS)

Thistlethwaite, Jason; Henstra, Daniel; Brown, Craig; Scott, Daniel

2018-02-01

Canada is a country in the midst of a flood management policy transition that is shifting part of the flood damage burden from the state to homeowners. This transition—as well as the large financial losses resulting from flooding—have created a window of opportunity for Canada to implement strategies that increase property owners' capacity to avoid and absorb the financial and physical risks associated with flooding. This work presents foundational research into the extent to which Canadians' flood experience, perceptions of flood risks and socio-demographics shape their intentions and adoption of property level flood protection (PLFP). A bilingual, national survey was deployed in Spring 2016 and was completed by 2300 respondents across all 10 Canadian provinces. The survey was developed using assumptions in existing literature on flood risk behaviours and the determinants of flood risk management in similar jurisdictions. The paper argues that property owners are not willing to accept greater responsibility for flood risk as envisioned by recent policy changes. This finding is consistent with other OECD jurisdictions, where flood risk engagement strategies have been developed that could be replicated in Canada to encourage risk-sharing behaviour.

Using risk-based analysis and geographic information systems to assess flooding problems in an urban watershed in Rhode Island.

PubMed

Hardmeyer, Kent; Spencer, Michael A

2007-04-01

This article provides an overview of the use of risk-based analysis (RBA) in flood damage assessment, and it illustrates the use of Geographic Information Systems (GIS) in identifying flood-prone areas, which can aid in flood-mitigation planning assistance. We use RBA to calculate expected annual flood damages in an urban watershed in the state of Rhode Island, USA. The method accounts for the uncertainty in the three primary relationships used in computing flood damage: (1) the probability that a given flood will produce a given amount of floodwater, (2) the probability that a given amount of floodwater will reach a certain stage or height, and (3) the probability that a certain stage of floodwater will produce a given amount of damage. A greater than 50% increase in expected annual flood damage is estimated for the future if previous development patterns continue and flood-mitigation measures are not taken. GIS is then used to create a map that shows where and how often floods might occur in the future, which can help (1) identify priority areas for flood-mitigation planning assistance and (2) disseminate information to public officials and other decision-makers.

Importance of record length with respect to estimating the 1-percent chance flood

USGS Publications Warehouse

Feaster, Toby D.

2010-01-01

U.S. Geological Survey (USGS) streamflow gages have been established in every State in the Nation, Puerto Rico, and the Trust Territory of the Pacific Islands. From these st reamflow records, estimates of the magnitude and frequency of floods are often developed and used to design transportation and water- conveyance structures to protect lives and property, and to determine flood-insurance rates. Probably the most recognizable flood statistic computed from USGS stream gaging records is the 1- percent (%) chance flood; better known has the 100-year flood. By definition, this is a flood that has a 1% chance of occurring in any given year. The 1% chance flood is a statistical estimate that can be significantly influenced by length of record and extreme flood events captured in that record. Consequently, it is typically recommended that flood statistics be updated on some regular interval such as every 10 years. This paper examines the influence of record length on the 1% chance flood for the Broad River in Georgia and the substantial difference that can occur in the estimate based on record length and the hydrologic conditions under which that record was collected. 

Flood disaster risk assessment of rural housings--a case study of Kouqian Town in China.

PubMed

Zhang, Qi; Zhang, Jiquan; Jiang, Liupeng; Liu, Xingpeng; Tong, Zhijun

2014-04-03

Floods are a devastating kind of natural disaster. About half of the population in China lives in rural areas. Therefore, it is necessary to assess the flood disaster risk of rural housings. The results are valuable for guiding the rescue and relief goods layout. In this study, we take the severe flood disaster that happened at Kouqian Town in Jilin, China in 2010 as an example to build an risk assessment system for flood disaster on rural housings. Based on the theory of natural disaster risk formation and "3S" technology (remote sensing, geography information systems and global positioning systems), taking the rural housing as the bearing body, we assess the flood disaster risk from three aspects: hazard, exposure and vulnerability. The hazard presented as the flood submerging range and depth. The exposure presented as the values of the housing and the property in it. The vulnerability presented as the relationship between the losses caused by flood and flood depth. We validate the model by the field survey after the flood disaster. The risk assessment results highly coincide with the field survey losses. This model can be used to assess the risk of other flood events in this area.

Transcriptome profiling of the floating-leaved aquatic plant Nymphoides peltata in response to flooding stress.

PubMed

Wu, Jinwei; Zhao, Hua-Bin; Yu, Dan; Xu, Xinwei

2017-01-31

Waterlogging or flooding is one of the most challenging abiotic stresses experienced by plants. Unlike many flooding-tolerant plants, floating-leaved aquatic plants respond actively to flooding stress by fast growth and elongation of its petioles to make leaves re-floating. However, the molecular mechanisms of this plant group responding to flood have not been investigated before. Here, we investigated the genetic basis of this adaptive response by characterizing the petiole transcriptomes of a floating-leaved species Nymphoides peltata under normal and flooding conditions. Clean reads under normal and flooding conditions with pooled sampling strategy were assembled into 124,302 unigenes. A total of 8883 unigenes were revealed to be differentially expressed between normal and flooding conditions. Among them, top ranked differentially expressed genes were mainly involved in antioxidant process, photosynthesis process and carbohydrate metabolism, including the glycolysis and a modified tricarboxylic acid cycle - alanine metabolism. Eight selected unigenes with significantly differentiated expression changes between normal and flooding conditions were validated by qRT-PCR. Among these processes, antioxidant process and glycolysis are commonly induced by waterlogging or flooding environment in plants, whereas photosynthesis and alanine metabolism are rarely occurred in other flooding-tolerant plants, suggesting the significant contributions of the two processes in the active response of N. peltata to flooding stress. Our results provide a valuable genomic resource for future studies on N. peltata and deepen our understanding of the genetic basis underlying the response to flooding stress in aquatic plants.

Direct local building inundation depth determination in 3-D point clouds generated from user-generated flood images

NASA Astrophysics Data System (ADS)

Griesbaum, Luisa; Marx, Sabrina; Höfle, Bernhard

2017-07-01

In recent years, the number of people affected by flooding caused by extreme weather events has increased considerably. In order to provide support in disaster recovery or to develop mitigation plans, accurate flood information is necessary. Particularly pluvial urban floods, characterized by high temporal and spatial variations, are not well documented. This study proposes a new, low-cost approach to determining local flood elevation and inundation depth of buildings based on user-generated flood images. It first applies close-range digital photogrammetry to generate a geo-referenced 3-D point cloud. Second, based on estimated camera orientation parameters, the flood level captured in a single flood image is mapped to the previously derived point cloud. The local flood elevation and the building inundation depth can then be derived automatically from the point cloud. The proposed method is carried out once for each of 66 different flood images showing the same building façade. An overall accuracy of 0.05 m with an uncertainty of ±0.13 m for the derived flood elevation within the area of interest as well as an accuracy of 0.13 m ± 0.10 m for the determined building inundation depth is achieved. Our results demonstrate that the proposed method can provide reliable flood information on a local scale using user-generated flood images as input. The approach can thus allow inundation depth maps to be derived even in complex urban environments with relatively high accuracies.

Near Real Time Flood Warning System for National Capital Territory of Delhi

NASA Astrophysics Data System (ADS)

Goyal, A.; Yadav, H.; Tyagi, H.; Gosain, A. K.

2017-12-01

Extreme floods are common phenomena during Indian Monsoons. The National Capital Territory area of India, Delhi, frequently experiences fluvial as well as pluvial inundation due to its proximity to river Yamuna and poor functioning of its stormwater drainage system. The urban floods result in severe waterlogging and heavy traffic snarls, bringing life in this megapolis to a halt. The city has witnessed six major floods since 1900 and thus its residents are well conscious of potential flood risks but the city still lacks a flood warning system. The flood related risks can be considerably reduced, if not eliminated, by issuing timely warnings and implementing adaptive measures. Therefore, the present study attempts to develop a web based platform that integrates Web-GIS technology and mathematical simulation modelling to provide an effective and reliable early flood warning service for Delhi. The study makes use of India Metorological Department's Doppler radar-derived near real time rainfall estimates of 15 minutes time step. The developed SWMM model has been validated using information from gauges, monitoring sensors and crowd sourcing techniques and utilises capabilities of cloud computing on server side for fast processing. This study also recommends safe evacuation policy and remedial measures for flooding hotspots as part of flood risk management plan. With heightened risk of floods in fast urbanizing areas, this work becomes highly pertinent as flood warning system with adequate lead time can not only save precious lives but can also substantially reduce flood damages.

Rethinking the relationship between flood risk perception and flood management.

PubMed

Birkholz, S; Muro, M; Jeffrey, P; Smith, H M

2014-04-15

Although flood risk perceptions and their concomitant motivations for behaviour have long been recognised as significant features of community resilience in the face of flooding events, there has, for some time now, been a poorly appreciated fissure in the accompanying literature. Specifically, rationalist and constructivist paradigms in the broader domain of risk perception provide different (though not always conflicting) contexts for interpreting evidence and developing theory. This contribution reviews the major constructs that have been applied to understanding flood risk perceptions and contextualises these within broader conceptual developments around risk perception theory and contemporary thinking around flood risk management. We argue that there is a need to re-examine and re-invigorate flood risk perception research, in a manner that is comprehensively underpinned by more constructivist thinking around flood risk management as well as by developments in broader risk perception research. We draw attention to an historical over-emphasis on the cognitive perceptions of those at risk to the detriment of a richer understanding of a wider range of flood risk perceptions such as those of policy-makers or of tax-payers who live outside flood affected areas as well as the linkages between these perspectives and protective measures such as state-supported flood insurance schemes. Conclusions challenge existing understandings of the relationship between risk perception and flood management, particularly where the latter relates to communication strategies and the extent to which those at risk from flooding feel responsible for taking protective actions. Copyright © 2014 Elsevier B.V. All rights reserved.

Stationarity analysis of historical flood series in France and Spain (14th-20th centuries)

NASA Astrophysics Data System (ADS)

Barriendos, M.; Coeur, D.; Lang, M.; Llasat, M. C.; Naulet, R.; Lemaitre, F.; Barrera, A.

Interdisciplinary frameworks for studying natural hazards and their temporal trends have an important potential in data generation for risk assessment, land use planning, and therefore the sustainable management of resources. This paper focuses on the adjustments required because of the wide variety of scientific fields involved in the reconstruction and characterisation of flood events for the past 1000 years. The aim of this paper is to describe various methodological aspects of the study of flood events in their historical dimension, including the critical evaluation of old documentary and instrumental sources, flood-event classification and hydraulic modelling, and homogeneity and quality control tests. Standardized criteria for flood classification have been defined and applied to the Isère and Drac floods in France, from 1600 to 1950, and to the Ter, the Llobregat and the Segre floods, in Spain, from 1300 to 1980. The analysis on the Drac and Isère data series from 1600 to the present day showed that extraordinary and catastrophic floods were not distributed uniformly in time. However, the largest floods (general catastrophic floods) were homogeneously distributed in time within the period 1600-1900. No major flood occurred during the 20th century in these rivers. From 1300 to the present day, no homogeneous behaviour was observed for extraordinary floods in the Spanish rivers. The largest floods were uniformly distributed in time within the period 1300-1900, for the Segre and Ter rivers.

A global assessment of the societal impacts of glacier outburst floods

NASA Astrophysics Data System (ADS)

Carrivick, Jonathan L.; Tweed, Fiona S.

2016-09-01

Glacier outburst floods are sudden releases of large amounts of water from a glacier. They are a pervasive natural hazard worldwide. They have an association with climate primarily via glacier mass balance and their impacts on society partly depend on population pressure and land use. Given the ongoing changes in climate and land use and population distributions there is therefore an urgent need to discriminate the spatio-temporal patterning of glacier outburst floods and their impacts. This study presents data compiled from 20 countries and comprising 1348 glacier floods spanning 10 centuries. Societal impacts were assessed using a relative damage index based on recorded deaths, evacuations, and property and infrastructure destruction and disruption. These floods originated from 332 sites; 70% were from ice-dammed lakes and 36% had recorded societal impact. The number of floods recorded has apparently reduced since the mid-1990s in all major world regions. Two thirds of sites that have produced > 5 floods (n = 32) have floods occurring progressively earlier in the year. Glacier floods have directly caused at least: 7 deaths in Iceland, 393 deaths in the European Alps, 5745 deaths in South America and 6300 deaths in central Asia. Peru, Nepal and India have experienced fewer floods yet higher levels of damage. One in five sites in the European Alps has produced floods that have damaged farmland, destroyed homes and damaged bridges; 10% of sites in South America have produced glacier floods that have killed people and damaged infrastructure; 15% of sites in central Asia have produced floods that have inundated farmland, destroyed homes, damaged roads and damaged infrastructure. Overall, Bhutan and Nepal have the greatest national-level economic consequences of glacier flood impacts. We recommend that accurate, full and standardised monitoring, recording and reporting of glacier floods is essential if spatio-temporal patterns in glacier flood occurrence, magnitude and societal impact are to be better understood. We note that future modelling of the global impact of glacier floods cannot assume that the same trends will continue and will need to consider combining land-use change with probability distributions of geomorphological responses to climate change and to human activity.

Observed and forecast flood-inundation mapping application-A pilot study of an eleven-mile reach of the White River, Indianapolis, Indiana

USGS Publications Warehouse

Kim, Moon H.; Morlock, Scott E.; Arihood, Leslie D.; Kiesler, James L.

2011-01-01

Near-real-time and forecast flood-inundation mapping products resulted from a pilot study for an 11-mile reach of the White River in Indianapolis. The study was done by the U.S. Geological Survey (USGS), Indiana Silver Jackets hazard mitigation taskforce members, the National Weather Service (NWS), the Polis Center, and Indiana University, in cooperation with the City of Indianapolis, the Indianapolis Museum of Art, the Indiana Department of Homeland Security, and the Indiana Department of Natural Resources, Division of Water. The pilot project showed that it is technically feasible to create a flood-inundation map library by means of a two-dimensional hydraulic model, use a map from the library to quickly complete a moderately detailed local flood-loss estimate, and automatically run the hydraulic model during a flood event to provide the maps and flood-damage information through a Web graphical user interface. A library of static digital flood-inundation maps was created by means of a calibrated two-dimensional hydraulic model. Estimated water-surface elevations were developed for a range of river stages referenced to a USGS streamgage and NWS flood forecast point colocated within the study reach. These maps were made available through the Internet in several formats, including geographic information system, Keyhole Markup Language, and Portable Document Format. A flood-loss estimate was completed for part of the study reach by using one of the flood-inundation maps from the static library. The Federal Emergency Management Agency natural disaster-loss estimation program HAZUS-MH, in conjunction with local building information, was used to complete a level 2 analysis of flood-loss estimation. A Service-Oriented Architecture-based dynamic flood-inundation application was developed and was designed to start automatically during a flood, obtain near real-time and forecast data (from the colocated USGS streamgage and NWS flood forecast point within the study reach), run the two-dimensional hydraulic model, and produce flood-inundation maps. The application used local building data and depth-damage curves to estimate flood losses based on the maps, and it served inundation maps and flood-loss estimates through a Web-based graphical user interface.

RASOR flood modelling

NASA Astrophysics Data System (ADS)

Beckers, Joost; Buckman, Lora; Bachmann, Daniel; Visser, Martijn; Tollenaar, Daniel; Vatvani, Deepak; Kramer, Nienke; Goorden, Neeltje

2015-04-01

Decision making in disaster management requires fast access to reliable and relevant information. We believe that online information and services will become increasingly important in disaster management. Within the EU FP7 project RASOR (Rapid Risk Assessment and Spatialisation of Risk) an online platform is being developed for rapid multi-hazard risk analyses to support disaster management anywhere in the world. The platform will provide access to a plethora of GIS data that are relevant to risk assessment. It will also enable the user to run numerical flood models to simulate historical and newly defined flooding scenarios. The results of these models are maps of flood extent, flood depths and flow velocities. The RASOR platform will enable to overlay historical event flood maps with observations and Earth Observation (EO) imagery to fill in gaps and assess the accuracy of the flood models. New flooding scenarios can be defined by the user and simulated to investigate the potential impact of future floods. A series of flood models have been developed within RASOR for selected case study areas around the globe that are subject to very different flood hazards: • The city of Bandung in Indonesia, which is prone to fluvial flooding induced by heavy rainfall. The flood hazard is exacerbated by land subsidence. • The port of Cilacap on the south coast of Java, subject to tsunami hazard from submarine earthquakes in the Sunda trench. • The area south of city of Rotterdam in the Netherlands, prone to coastal and/or riverine flooding. • The island of Santorini in Greece, which is subject to tsunamis induced by landslides. Flood models have been developed for each of these case studies using mostly EO data, augmented by local data where necessary. Particular use was made of the new TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) product from the German Aerospace centre (DLR) and EADS Astrium. The presentation will describe the flood models and the flooding scenarios that can be defined by the RASOR end user to support risk management in each area. Ongoing work for three more case studies (Haiti, Po valley in Italy and Jakarta, Indonesia) will also be discussed.

Influence Assessment of Multiple Large-sized Reservoirs on Flooding in the Huai River Watershed, China

NASA Astrophysics Data System (ADS)

Wan, X. Y.

2017-12-01

The extensive constructions of reservoirs change the hydrologic characteristics of the associated watersheds, which obviously increases the complexity of watershed flood control decisions. By evaluating the impacts of the multi-reservoir system on the flood hydrograph, it becomes possible to improve the effectiveness of the flood control decisions. In this paper we compare the non-reservoir flood hydrograph with the actual observed flood hydrograph using the Lutaizi upstream of Huai river in East China as a representative case, where 20 large-scale/large-sized reservoirs have been built. Based on the total impact of the multi-reservoir system, a novel strategy, namely reservoir successively added (RSA) method, is presented to evaluate the contribution of each reservoir to the total impact. According each reservoir contribution, the "highly effective" reservoirs for watershed flood control are identified via hierarchical clustering. Moreover, we estimate further the degree of impact of the reservoir current operation rules on the flood hydrograph on the base of the impact of dams themselves. As a result, we find that the RSA method provides a useful method for analysis of multi-reservoir systems by partitioning the contribution of each reservoir to the total impacts on the flooding at the downstream section. For all the historical large floods examined, the multi-reservoir system in the Huai river watershed has a significant impact on flooding at the downstream Lutaizi section, on average reducing the flood volume and peak discharge by 13.92 × 108 m3 and 18.7% respectively. It is more informative to evaluate the maximum impact of each reservoir (on flooding at the downstream section) than to examine the average impact. Each reservoir has a different impact on the flood hydrograph at the Lutaizi section. In particular, the Meishan, Xianghongdian, Suyahu, Nanwan, Nianyushan and Foziling reservoirs exert a strong influence on the flood hydrograph, and are therefore important for flood control on the Huai river. Under the current operation rules, the volume and peak discharge of flooding at the Lutaizi section are reduced by 13.69 × 108m3 and 1429 m3/s respectively, accounting for 98% and 80.5% of the real reduction respectively.

Towards a Flood Severity Index

NASA Astrophysics Data System (ADS)

Kettner, A.; Chong, A.; Prades, L.; Brakenridge, G. R.; Muir, S.; Amparore, A.; Slayback, D. A.; Poungprom, R.

2017-12-01

Flooding is the most common natural hazard worldwide, affecting 21 million people every year. In the immediate moments following a flood event, humanitarian actors like the World Food Program need to make rapid decisions ( 72 hrs) on how to prioritize affected areas impacted by such an event. For other natural disasters like hurricanes/cyclones and earthquakes, there are industry-recognized standards on how the impacted areas are to be classified. Shake maps, quantifying peak ground motion, from for example the US Geological Survey are widely used for assessing earthquakes. Similarly, cyclones are tracked by Joint Typhoon Warning Center (JTWC) and Global Disaster Alert and Coordination System (GDACS) who release storm nodes and tracks (forecasted and actual), with wind buffers and classify the event according to the Saffir-Simpson Hurricane Wind Scale. For floods, the community is usually able to acquire unclassified data of the flood extent as identified from satellite imagery. Most often no water discharge hydrograph is available to classify the event into recurrence intervals simply because there is no gauging station, or the gauging station was unable to record the maximum discharge due to overtopping or flood damage. So, the question remains: How do we methodically turn a flooded area into classified areas of different gradations of impact? Here, we present a first approach towards developing a global applicable flood severity index. The flood severity index is set up such that it considers relatively easily obtainable physical parameters in a short period of time like: flood frequency (relating the current flood to historical events) and magnitude, as well as land cover, slope, and where available pre-event simulated flood depth. The scale includes categories ranging from very minor flooding to catastrophic flooding. We test and evaluate the postulated classification scheme against a set of past flood events. Once a severity category is determined, socio-economic data, such as population density, infrastructure, urbanization or equivalent information, is required for humanitarian actors to respond properly. In the end, expanded monitoring of floods, improved mitigation measures, but also effective communication of the severity of an event has the potential to reduce loss of life in future flood events.

Flood Damage and Loss Estimation for Iowa on Web-based Systems using HAZUS

NASA Astrophysics Data System (ADS)

Yildirim, E.; Sermet, M. Y.; Demir, I.

2016-12-01

Importance of decision support systems for flood emergency response and loss estimation increases with its social and economic impacts. To estimate the damage of the flood, there are several software systems available to researchers and decision makers. HAZUS-MH is one of the most widely used desktop program, developed by FEMA (Federal Emergency Management Agency), to estimate economic loss and social impacts of disasters such as earthquake, hurricane and flooding (riverine and coastal). HAZUS used loss estimation methodology and implements through geographic information system (GIS). HAZUS contains structural, demographic, and vehicle information across United States. Thus, it allows decision makers to understand and predict possible casualties and damage of the floods by running flood simulations through GIS application. However, it doesn't represent real time conditions because of using static data. To close this gap, an overview of a web-based infrastructure coupling HAZUS and real time data provided by IFIS (Iowa Flood Information System) is presented by this research. IFIS is developed by the Iowa Flood Center, and a one-stop web-platform to access community-based flood conditions, forecasts, visualizations, inundation maps and flood-related data, information, and applications. Large volume of real-time observational data from a variety of sensors and remote sensing resources (radars, rain gauges, stream sensors, etc.) and flood inundation models are staged on a user-friendly maps environment that is accessible to the general public. Providing cross sectional analyses between HAZUS-MH and IFIS datasets, emergency managers are able to evaluate flood damage during flood events easier and more accessible in real time conditions. With matching data from HAZUS-MH census tract layer and IFC gauges, economical effects of flooding can be observed and evaluated by decision makers. The system will also provide visualization of the data by using augmented reality for see-through displays. Emergency management experts can take advantage of this visualization mode to manage flood response activities in real time. Also, forecast system developed by the Iowa Flood Center will be used to predict probable damage of the flood.

Coupling Radar Rainfall Estimation and Hydrological Modelling For Flash-flood Hazard Mitigation

NASA Astrophysics Data System (ADS)

Borga, M.; Creutin, J. D.

Flood risk mitigation is accomplished through managing either or both the hazard and vulnerability. Flood hazard may be reduced through structural measures which alter the frequency of flood levels in the area. The vulnerability of a community to flood loss can be mitigated through changing or regulating land use and through flood warning and effective emergency response. When dealing with flash-flood hazard, it is gener- ally accepted that the most effective way (and in many instances the only affordable in a sustainable perspective) to mitigate the risk is by reducing the vulnerability of the involved communities, in particular by implementing flood warning systems and community self-help programs. However, both the inherent characteristics of the at- mospheric and hydrologic processes involved in flash-flooding and the changing soci- etal needs provide a tremendous challenge to traditional flood forecasting and warning concepts. In fact, the targets of these systems are traditionally localised like urbanised sectors or hydraulic structures. Given the small spatial scale that characterises flash floods and the development of dispersed urbanisation, transportation, green tourism and water sports, human lives and property are exposed to flash flood risk in a scat- tered manner. This must be taken into consideration in flash flood warning strategies and the investigated region should be considered as a whole and every section of the drainage network as a potential target for hydrological warnings. Radar technology offers the potential to provide information describing rain intensities almost contin- uously in time and space. Recent research results indicate that coupling radar infor- mation to distributed hydrologic modelling can provide hydrologic forecasts at all potentially flooded points of a region. Nevertheless, very few flood warning services use radar data more than on a qualitative basis. After a short review of current under- standing in this area, two issues are examined: advantages and caveats of using radar rainfall estimates in operational flash flood forecasting, methodological problems as- sociated to the use of hydrological models for distributed flash flood forecasting with rainfall input estimated from radar.

An exploration of factors affecting the long term psychological impact and deterioration of mental health in flooded households.

PubMed

Lamond, Jessica Elizabeth; Joseph, Rotimi D; Proverbs, David G

2015-07-01

The long term psychological effect of the distress and trauma caused by the memory of damage and losses associated with flooding of communities remains an under researched impact of flooding. This is particularly important for communities that are likely to be repeatedly flooded where levels of mental health disorder will damage long term resilience to future flooding. There are a variety of factors that affect the prevalence of mental health disorders in the aftermath of flooding including pre-existing mental health, socio-economic factors and flood severity. However previous research has tended to focus on the short term impacts immediately following the flood event and much less focus has been given to the longer terms effects of flooding. Understanding of factors affecting the longer term mental health outcomes for flooded households is critical in order to support communities in improving social resilience. Hence, the aim of this study was to explore the characteristics associated with psychological distress and mental health deterioration over the longer term. The research examined responses from a postal survey of households flooded during the 2007 flood event across England. Descriptive statistics, correlation analysis and binomial logistic regression were applied to data representing household characteristics, flood event characteristics and post-flood stressors and coping strategies. These factors were related to reported measures of stress, anxiety, depression and mental health deterioration. The results showed that household income, depth of flooding; having to move out during reinstatement and mitigating actions are related to the prevalence of psycho-social symptoms in previously flooded households. In particular relocation and household income were the most predictive factors. The practical implication of these findings for recovery after flooding are: to consider the preferences of households in terms of the need to move out during restorative building works and the financial resource constraints that may lead to severe mental hardship. In addition the findings suggest that support with installing mitigation measures may lead to improved mental health outcomes for communities at risk. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

The Influence Of Antecedent Conditions On Flood Risk In Sub-Saharan Africa

NASA Astrophysics Data System (ADS)

Bischiniotis, K.

2017-12-01

Flood risk management has traditionally focused on long-term flood protection measures. However, due to high investment costs many lower-income countries are not able to afford hard infrastructure that provides the desired safety levels. Consequently, timely warning of not only extreme events is crucial in risk mitigation at these places. Most flood warning systems have predominantly focused on precipitation as the main predictive factor with lead times of hours or days. Nevertheless, other factors such as anomalous positive water storage, soil saturation and evapotranspiration also affect the flood build-up period. Gaining insights in the processes occurring during this period can increase warning lead times, resulting in more effective preparation. This study follows a pragmatic approach to analyse the hydro-meteorological pre-conditions of 501 damaging floods over the period 1980 to 2010 in sub-Saharan Africa. These are separated into a) weather scale (0-7 days) and b) seasonal scale conditions (up to 6 months) before each event in a way that the two periods do not overlap. The 7-day preceding precipitation (PRE7) and the Standardized Precipitation Evapotranspiration Index (SPEI) reflect the conditions in the two time scale domains, respectively. Using the flood onset date and the location derived from NatCatSERVICE database, the antecedent conditions of each flood are systematically compared to the same conditions during the other years of the dataset, during which no floods were reported. Results indicate that high PRE7 does not always justify the flood generation by itself since there were several cases where similar magnitude precipitation events did not lead to flooding. The SPEI in the end of the flood onset month seems to be a good flood monitoring tool as in most cases it well reflects the wet conditions (80% of the floods). The SPEIs of different averaging times prior to flood events also show that many floods were preceded by wet conditions (70% , 65%, and 57% for averaging time of 1, 3 and 6 months, respectively. Finally, we show that bringing together weather and seasonal-scale conditions can result in an increased flooding likelihood, which in turn might help humanitarian organizations and decision-makers extend the period of the preventive flood risk management planning.

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

NASA Astrophysics Data System (ADS)

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 coincidence into account. All hazards - fluvial, pluvial and combined - were accompanied by an uncertainty estimation taking into account 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 percentile maps. The results are critically discussed and their usage in flood risk management are outlined.

Impacts of floods on dysentery in Xinxiang city, China, during 2004-2010: a time-series Poisson analysis.

PubMed

Ni, Wei; Ding, Guoyong; Li, Yifei; Li, Hongkai; Jiang, Baofa

2014-01-01

Xinxiang, a city in Henan Province, suffered from frequent floods due to persistent and heavy precipitation from 2004 to 2010. In the same period, dysentery was a common public health problem in Xinxiang, with the proportion of reported cases being the third highest among all the notified infectious diseases. We focused on dysentery disease consequences of different degrees of floods and examined the association between floods and the morbidity of dysentery on the basis of longitudinal data during the study period. A time-series Poisson regression model was conducted to examine the relationship between 10 times different degrees of floods and the monthly morbidity of dysentery from 2004 to 2010 in Xinxiang. Relative risks (RRs) of moderate and severe floods on the morbidity of dysentery were calculated in this paper. In addition, we estimated the attributable contributions of moderate and severe floods to the morbidity of dysentery. A total of 7591 cases of dysentery were notified in Xinxiang during the study period. The effect of floods on dysentery was shown with a 0-month lag. Regression analysis showed that the risk of moderate and severe floods on the morbidity of dysentery was 1.55 (95% CI: 1.42-1.670) and 1.74 (95% CI: 1.56-1.94), respectively. The attributable risk proportions (ARPs) of moderate and severe floods to the morbidity of dysentery were 35.53 and 42.48%, respectively. This study confirms that floods have significantly increased the risk of dysentery in the study area. In addition, severe floods have a higher proportional contribution to the morbidity of dysentery than moderate floods. Public health action should be taken to avoid and control a potential risk of dysentery epidemics after floods.

Impacts of floods on dysentery in Xinxiang city, China, during 2004–2010: a time-series Poisson analysis

PubMed Central

Ni, Wei; Ding, Guoyong; Li, Yifei; Li, Hongkai; Jiang, Baofa

2014-01-01

Background Xinxiang, a city in Henan Province, suffered from frequent floods due to persistent and heavy precipitation from 2004 to 2010. In the same period, dysentery was a common public health problem in Xinxiang, with the proportion of reported cases being the third highest among all the notified infectious diseases. Objectives We focused on dysentery disease consequences of different degrees of floods and examined the association between floods and the morbidity of dysentery on the basis of longitudinal data during the study period. Design A time-series Poisson regression model was conducted to examine the relationship between 10 times different degrees of floods and the monthly morbidity of dysentery from 2004 to 2010 in Xinxiang. Relative risks (RRs) of moderate and severe floods on the morbidity of dysentery were calculated in this paper. In addition, we estimated the attributable contributions of moderate and severe floods to the morbidity of dysentery. Results A total of 7591 cases of dysentery were notified in Xinxiang during the study period. The effect of floods on dysentery was shown with a 0-month lag. Regression analysis showed that the risk of moderate and severe floods on the morbidity of dysentery was 1.55 (95% CI: 1.42–1.670) and 1.74 (95% CI: 1.56–1.94), respectively. The attributable risk proportions (ARPs) of moderate and severe floods to the morbidity of dysentery were 35.53 and 42.48%, respectively. Conclusions This study confirms that floods have significantly increased the risk of dysentery in the study area. In addition, severe floods have a higher proportional contribution to the morbidity of dysentery than moderate floods. Public health action should be taken to avoid and control a potential risk of dysentery epidemics after floods. PMID:25098726

The Complex Relationship Between Heavy Storms and Floods: Implication on Stormwater Drainage design and Management

NASA Astrophysics Data System (ADS)

Demissie, Y.; Mortuza, M. R.; Moges, E.; Yan, E.; Li, H. Y.

2017-12-01

Due to the lack of historical and future streamflow data for flood frequency analysis at or near most drainage sites, it is a common practice to directly estimate the design flood (maximum discharge or volume of stream for a given return period) based on storm frequency analysis and the resulted Intensity-Duration-Frequency (IDF) curves. Such analysis assumes a direct relationship between storms and floods with, for example, the 10-year rainfall expected to produce the 10-year flood. However, in reality, a storm is just one factor among the many other hydrological and metrological factors that can affect the peak flow and hydrograph. Consequently, a heavy storm does not necessarily always lead to flooding or a flood events with the same frequency. This is evident by the observed difference in the seasonality of heavy storms and floods in most regions. In order to understand site specific causal-effect relationship between heavy storms and floods and improve the flood analysis for stormwater drainage design and management, we have examined the contributions of various factors that affect floods using statistical and information theory methods. Based on the identified dominant causal-effect relationships, hydrologic and probability analyses were conducted to develop the runoff IDF curves taking into consideration the snowmelt and rain-on-snow effect, the difference in the storm and flood seasonality, soil moisture conditions, and catchment potential for flash and riverine flooding. The approach was demonstrated using data from military installations located in different parts of the United States. The accuracy of the flood frequency analysis and the resulted runoff IDF curves were evaluated based on the runoff IDF curves developed from streamflow measurements.

Swiss Re Global Flood Hazard Zones: Know your flood risk

NASA Astrophysics Data System (ADS)

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.

Amplification of flood frequencies with local sea level rise and emerging flood regimes

NASA Astrophysics Data System (ADS)

Buchanan, Maya K.; Oppenheimer, Michael; Kopp, Robert E.

2017-06-01

The amplification of flood frequencies by sea level rise (SLR) is expected to become one of the most economically damaging impacts of climate change for many coastal locations. Understanding the magnitude and pattern by which the frequency of current flood levels increase is important for developing more resilient coastal settlements, particularly since flood risk management (e.g. infrastructure, insurance, communications) is often tied to estimates of flood return periods. The Intergovernmental Panel on Climate Change’s Fifth Assessment Report characterized the multiplication factor by which the frequency of flooding of a given height increases (referred to here as an amplification factor; AF). However, this characterization neither rigorously considered uncertainty in SLR nor distinguished between the amplification of different flooding levels (such as the 10% versus 0.2% annual chance floods); therefore, it may be seriously misleading. Because both historical flood frequency and projected SLR are uncertain, we combine joint probability distributions of the two to calculate AFs and their uncertainties over time. Under probabilistic relative sea level projections, while maintaining storm frequency fixed, we estimate a median 40-fold increase (ranging from 1- to 1314-fold) in the expected annual number of local 100-year floods for tide-gauge locations along the contiguous US coastline by 2050. While some places can expect disproportionate amplification of higher frequency events and thus primarily a greater number of historically precedented floods, others face amplification of lower frequency events and thus a particularly fast growing risk of historically unprecedented flooding. For example, with 50 cm of SLR, the 10%, 1%, and 0.2% annual chance floods are expected respectively to recur 108, 335, and 814 times as often in Seattle, but 148, 16, and 4 times as often in Charleston, SC.

How do we best estimate fluvial flood risk in urban environments? : The case of the city of Eilenburg, Germany

NASA Astrophysics Data System (ADS)

Longo, Elisa; Tito Aronica, Giuseppe; Di Baldassarre, Giuliano; Mukolwe, Micah

2015-04-01

Flooding is one of the most impactful natural hazards. In particular, by looking at the data of damages from natural hazards in Europe collected in the International Disaster Database (EM-DAT) one can see a significant increase over the past four decades of both frequency of floods and associated economic damages. Similarly, dramatic trends are also found by analyzing other types of flood losses, such as the number of people affected by floods, homeless, injured or killed. To deal with the aforementioned increase of flood risk, more and more efforts are being made to promote integrated flood risk management, for instance, at the end of 2007, the European Community (EC) issued the Flood Directive (F.D.) 2007/60/EC. One of the major innovations was that the F.D. 2007/60/C requires Member State to carry out risk maps and then take appropriate measures to reduce the evaluated risk. The main goal of this research was to estimate flood damaging using a computer code based on a recently developed method (KULTURisk, www.kulturisk.eu) and to compare the estimated damage with the observed one. The study area was the municipality of Eilenburg, which in 2002 was subjected to a destructive flood event. Were produced flood damage maps with new procedures (e.g. KULTURisk) and compared the estimates with observed data. This study showed the possibility to extend the lesson learned with the Eilenburg case study in other similar contexts. The outcomes of this test provided interesting insights about the flood risk mapping, which are expected to contribute to raise awareness to the flooding issues,to plan (structural and/or non-structural) measures of flood risk reduction and to support better land-use and urban planning.

Recent trends in the frequency and duration of global floods

NASA Astrophysics Data System (ADS)

Najibi, Nasser; Devineni, Naresh

2018-06-01

Frequency and duration of floods are analyzed using the global flood database of the Dartmouth Flood Observatory (DFO) to explore evidence of trends during 1985-2015 at global and latitudinal scales. Three classes of flood duration (i.e., short: 1-7, moderate: 8-20, and long: 21 days and above) are also considered for this analysis. The nonparametric Mann-Kendall trend analysis is used to evaluate three hypotheses addressing potential monotonic trends in the frequency of flood, moments of duration, and frequency of specific flood duration types. We also evaluated if trends could be related to large-scale atmospheric teleconnections using a generalized linear model framework. Results show that flood frequency and the tails of the flood duration (long duration) have increased at both the global and the latitudinal scales. In the tropics, floods have increased 4-fold since the 2000s. This increase is 2.5-fold in the north midlatitudes. However, much of the trend in frequency and duration of the floods can be placed within the long-term climate variability context since the Atlantic Multidecadal Oscillation, North Atlantic Oscillation, and Pacific Decadal Oscillation were the main atmospheric teleconnections explaining this trend. There is no monotonic trend in the frequency of short-duration floods across all the global and latitudinal scales. There is a significant increasing trend in the annual median of flood durations globally and each latitudinal belt, and this trend is not related to these teleconnections. While the DFO data come with a certain level of epistemic uncertainty due to imprecision in the estimation of floods, overall, the analysis provides insights for understanding the frequency and persistence in hydrologic extremes and how they relate to changes in the climate, organization of global and local dynamical systems, and country-scale socioeconomic factors.

The Use of LIDAR and Volunteered Geographic Information to Map Flood Extents and Inundation

NASA Astrophysics Data System (ADS)

McDougall, K.; Temple-Watts, P.

2012-07-01

Floods are one of the most destructive natural disasters that threaten communities and properties. In recent decades, flooding has claimed more lives, destroyed more houses and ruined more agricultural land than any other natural hazard. The accurate prediction of the areas of inundation from flooding is critical to saving lives and property, but relies heavily on accurate digital elevation and hydrologic models. The 2011 Brisbane floods provided a unique opportunity to capture high resolution digital aerial imagery as the floods neared their peak, allowing the capture of areas of inundation over the various city suburbs. This high quality imagery, together with accurate LiDAR data over the area and publically available volunteered geographic imagery through repositories such as Flickr, enabled the reconstruction of flood extents and the assessment of both area and depth of inundation for the assessment of damage. In this study, approximately 20 images of flood damaged properties were utilised to identify the peak of the flood. Accurate position and height values were determined through the use of RTK GPS and conventional survey methods. This information was then utilised in conjunction with river gauge information to generate a digital flood surface. The LiDAR generated DEM was then intersected with the flood surface to reconstruct the area of inundation. The model determined areas of inundation were then compared to the mapped flood extent from the high resolution digital imagery to assess the accuracy of the process. The paper concludes that accurate flood extent prediction or mapping is possible through this method, although its accuracy is dependent on the number and location of sampled points. The utilisation of LiDAR generated DEMs and DSMs can also provide an excellent mechanism to estimate depths of inundation and hence flood damage

The Two Edged Sword; Illinois' Risk Reduction Success Through Managed Retreat And Strong Regulations

NASA Astrophysics Data System (ADS)

Osman, P.

2017-12-01

Illinois has the nation's largest inland system of rivers, lakes, and streams. Two thirds of the continental US and two Canadian provinces drain thru Illinois. Although a blessing, these waterways also result in frequent flooding. Historically, Illinois ranked among the top five states in the nation for flood losses. However, using a combination of strong floodplain regulations and proactive flood mitigation programs, Illinois now ranks near the bottom of flood loss states. Following the 1993 flood, the State of Illinois began an aggressive program to remove flood prone structures from the floodplain. Using a combination of state, federal, and local funds, towns like Valmeyer and Grafton have largely been relocated outside of the floodplain. Likewise, in dozens of communities across the state, thousands of structures have been have purchased to create open space in the floodplain. In addition, new structures in the floodplain must meet strict state and local floodplain construction standards. Major floods now routinely pass Illinois unnoticed. Many communities once ravaged by flooding now pass large floods unscathed. Due largely to climate change, flood losses in many areas are evolving. The majority of flood losses in Illinois now occur outside of the mapped floodplain. The State of Illinois has recently completed a detailed analysis of the state's urban flood exposure. Flood risk is changing and methods to address that risk must evolve accordingly. Accurate climate change data on major inland waterways and urban areas remain elusive. This presentation will highlight simple steps any state or community can take to reduce existing flood losses and be better prepared to address changing impacts due to climate change.

Impact of Flooding on Land Use/ Land Cover Transformation in Wular Lake and its Environs, Kashmir Valley, India Using Geoinformatics

NASA Astrophysics Data System (ADS)

Ahmad, T.; Pandey, A. C.; Kumar, A.

2017-11-01

Wular lake, located at an elevation of 1520 m above sea level in Kashmir valley, India. In the present study, the immediate and long term impact of flood (2014) over the Wular lake environs was analyzed by using satellite images and employing supervised classification technique in GIS environment. The LULC classification was performed on the images of 25th August 2014 (pre flood) and 13th September 2015 (post flood) and was compared, which indicated marked decrease in terrestrial vegetation (23.7 %), agriculture (43.7 %) and water bodies (39.9 %). Overlaying analysis was performed with pre and post flood classified images with reference to the satellite image of 10th September 2014(during flood) which indicated total area inundated during flood was 88.77 km2. With the pre-flood situation, the aquatic vegetation of 34.06 km2, 13.89 km2 of agriculture land and terrestrial vegetation of 3.13 km2 was inundated. In the post flood situation, it was also came into focus that more than the half of the area under water bodies was converted into sand deposits (22.76 km2) due to anomalous increase in siltation. The overlay analysis on post flood classified image indicated that aquatic vegetation followed by agriculture and sand deposits lie within the flood inundated area. Further spatial analysis was performed within the flood inundated area (88.77 km2) with pre and post classified image to understand the situation before and after the flood and to calculate the changes. These land use-land cover transformations signifies the ill effect of flooding on the biodiversity of Wular Lake.

Evaluation of the magnitude and frequency of floods in urban watersheds in Phoenix and Tucson, Arizona

USGS Publications Warehouse

Kennedy, Jeffrey R.; Paretti, Nicholas V.

2014-01-01

Flooding in urban areas routinely causes severe damage to property and often results in loss of life. To investigate the effect of urbanization on the magnitude and frequency of flood peaks, a flood frequency analysis was carried out using data from urbanized streamgaging stations in Phoenix and Tucson, Arizona. Flood peaks at each station were predicted using the log-Pearson Type III distribution, fitted using the expected moments algorithm and the multiple Grubbs-Beck low outlier test. The station estimates were then compared to flood peaks estimated by rural-regression equations for Arizona, and to flood peaks adjusted for urbanization using a previously developed procedure for adjusting U.S. Geological Survey rural regression peak discharges in an urban setting. Only smaller, more common flood peaks at the 50-, 20-, 10-, and 4-percent annual exceedance probabilities (AEPs) demonstrate any increase in magnitude as a result of urbanization; the 1-, 0.5-, and 0.2-percent AEP flood estimates are predicted without bias by the rural-regression equations. Percent imperviousness was determined not to account for the difference in estimated flood peaks between stations, either when adjusting the rural-regression equations or when deriving urban-regression equations to predict flood peaks directly from basin characteristics. Comparison with urban adjustment equations indicates that flood peaks are systematically overestimated if the rural-regression-estimated flood peaks are adjusted upward to account for urbanization. At nearly every streamgaging station in the analysis, adjusted rural-regression estimates were greater than the estimates derived using station data. One likely reason for the lack of increase in flood peaks with urbanization is the presence of significant stormwater retention and detention structures within the watershed used in the study.

Utilizing NASA Earth Observations to Enhance Flood Impact Products and Mitigation in the Lower Mekong Water Basin

NASA Astrophysics Data System (ADS)

Doyle, C.; Gao, M.; Spruce, J.; Bolten, J. D.; Weber, S.

2014-12-01

This presentation discusses results of a project to develop a near real time flood monitoring capability for the Lower Mekong Water Basin (LMB), the largest river basin in Southeast Asia and home to more than sixty million people. The region has seen rapid population growth and socio-economic development, fueling unsustainable deforestation, agricultural expansion, and stream-flow regulation. The basin supports substantial rice farming and other agrarian activities, which heavily depend upon seasonal flooding. But, floods due to typhoons and other severe weather events can result in disasters that cost millions of dollars and cause hardships to millions of people. This study uses near real time and historical Aqua and Terra MODIS 250-m resolution Normalized Difference Vegetation Index (NDVI) products to map flood and drought impact within the LMB. In doing so, NDVI change products are derived by comparing from NDVI during the wet season to a baseline NDVI from the dry season. The method records flood events, which cause drastic decreases in NDVI compared to non-flooded conditions. NDVI change product computation was automated for updating a near real-time system, as part of the Committee on Earth Observing Satellites Disaster Risk Management Observation Strategy. The system is a web-based 'Flood Dashboard that will showcase MODIS flood monitoring products, along with other flood mapping and weather data products. This flood dashboard enables end-users to view and assess a variety of geospatial data to monitor floods and flood impacts in near real-time, as well provides a platform for further data aggregation for flood prediction modeling and post-event assessment.

Simulation of Flood Profiles for Catoma Creek near Montgomery, Alabama, 2008

USGS Publications Warehouse

Lee, K.G.; Hedgecock, T.S.

2008-01-01

A one-dimensional step-backwater model was used to simulate flooding conditions for Catoma Creek near Montgomery, Alabama. A peak flow of 50,000 cubic feet per second was computed by the U.S. Geological Survey for the March 1990 flood at the Norman Bridge Road gaging station. Using this estimated peak flow, flood-plain surveys with associated roughness coefficients, and surveyed high-water marks for the March 1990 flood, a flow model was calibrated to closely match the known event. The calibrated model then was used to simulate flooding for the 10-, 50-, 100-, and 500-year recurrence-interval floods. The 100-year flood stage for the Alabama River also was computed in the vicinity of the Catoma Creek confluence using observed high-water profiles from the 1979 and 1990 floods and gaging-station data. The results indicate that the 100-year flood profile for Catoma Creek within the 15-mile study reach is about 2.5 feet higher, on average, than the profile published by the Federal Emergency Management Agency. The maximum and minimum differences are 6.0 feet and 0.8 foot, respectively. All water-surface elevations computed for the 100-year flood are higher than those published by the Federal Emergency Management Agency. The 100-year flood stage computed for the Alabama River in the vicinity of the Catoma Creek confluence was about 4.5 feet lower than the elevation published by the Federal Emergency Management Agency. The results of this study provide the community with flood-profile information that can be used for flood-plain mitigation, future development, and safety plans for the city.

Extraordinary flood response of a small urban watershed to short-duration convective rainfall

USGS Publications Warehouse

Smith, J.A.; Miller, A.J.; Baeck, M.L.; Nelson, P.A.; Fisher, G.T.; Meierdiercks, K.L.

2005-01-01

The 9.1 km2 Moores Run watershed in Baltimore, Maryland, experiences floods with unit discharge peaks exceeding 1 m3 s-1 km-2 12 times yr-1, on average. Few, if any, drainage basins in the continental United States have a higher frequency. A thunderstorm system on 13 June 2003 produced the record flood peak (13.2 m3 s-1 km-2) during the 6-yr stream gauging record of Moores Run. In this paper, the hydrometeorology, hydrology, and hydraulics of extreme floods in Moores Run are examined through analyses of the 13 June 2003 storm and flood, as well as other major storm and flood events during the 2000-03 time period. The 13 June 2003 flood, like most floods in Moores Run, was produced by an organized system of thunderstorms. Analyses of the 13 June 2003 storm, which are based on volume scan reflectivity observations from the Sterling, Virginia, WSR-88D radar, are used to characterize the spatial and temporal variability of flash flood producing rainfall. Hydrology of flood response in Moores Run is characterized by highly efficient concentration of runoff through the storm drain network and relatively low runoff ratios. A detailed survey of high-water marks for the 13 June 2003 flood is used, in combination with analyses based on a 2D, depth-averaged open channel flow model (TELEMAC 2D) to examine hydraulics of the 13 June 2003 flood. Hydraulic analyses are used to examine peak discharge estimates for the 13 June flood peak, propagation of flood waves in the Moores Run channel, and 2D flow features associated with channel and floodplain geometry. ?? 2005 American Meteorological Society.

Effect of catchment properties and flood generation regime on copula selection for bivariate flood frequency analysis

NASA Astrophysics Data System (ADS)

Filipova, Valeriya; Lawrence, Deborah; Klempe, Harald

2018-02-01

Applying copula-based bivariate flood frequency analysis is advantageous because the results provide information on both the flood peak and volume. More data are, however, required for such an analysis, and it is often the case that only data series with a limited record length are available. To overcome this issue of limited record length, data regarding climatic and geomorphological properties can be used to complement statistical methods. In this paper, we present a study of 27 catchments located throughout Norway, in which we assess whether catchment properties, flood generation processes and flood regime have an effect on the correlation between flood peak and volume and, in turn, on the selection of copulas. To achieve this, the annual maximum flood events were first classified into events generated primarily by rainfall, snowmelt or a combination of these. The catchments were then classified into flood regime, depending on the predominant flood generation process producing the annual maximum flood events. A contingency table and Fisher's exact test were used to determine the factors that affect the selection of copulas in the study area. The results show that the two-parameter copulas BB1 and BB7 are more commonly selected in catchments with high steepness, high mean annual runoff and rainfall flood regime. These findings suggest that in these types of catchments, the dependence structure between flood peak and volume is more complex and cannot be modeled effectively using a one-parameter copula. The results illustrate that by relating copula types to flood regime and catchment properties, additional information can be supplied for selecting copulas in catchments with limited data.

Using integrated modeling for generating watershed-scale dynamic flood maps for Hurricane Harvey

NASA Astrophysics Data System (ADS)

Saksena, S.; Dey, S.; Merwade, V.; Singhofen, P. J.

2017-12-01

Hurricane Harvey, which was categorized as a 1000-year return period event, produced unprecedented rainfall and flooding in Houston. Although the expected rainfall was forecasted much before the event, there was no way to identify which regions were at higher risk of flooding, the magnitude of flooding, and when the impacts of rainfall would be highest. The inability to predict the location, duration, and depth of flooding created uncertainty over evacuation planning and preparation. This catastrophic event highlighted that the conventional approach to managing flood risk using 100-year static flood inundation maps is inadequate because of its inability to predict flood duration and extents for 500-year or 1000-year return period events in real-time. The purpose of this study is to create models that can dynamically predict the impacts of rainfall and subsequent flooding, so that necessary evacuation and rescue efforts can be planned in advance. This study uses a 2D integrated surface water-groundwater model called ICPR (Interconnected Channel and Pond Routing) to simulate both the hydrology and hydrodynamics for Hurricane Harvey. The methodology involves using the NHD stream network to create a 2D model that incorporates rainfall, land use, vadose zone properties and topography to estimate streamflow and generate dynamic flood depths and extents. The results show that dynamic flood mapping captures the flood hydrodynamics more accurately and is able to predict the magnitude, extent and time of occurrence for extreme events such as Hurricane Harvey. Therefore, integrated modeling has the potential to identify regions that are more susceptible to flooding, which is especially useful for large-scale planning and allocation of resources for protection against future flood risk.

The 1965 Mississippi River flood in Iowa

USGS Publications Warehouse

Schwob, Harlan H.; Myers, Richard E.

1965-01-01

Flood data compiled for the part of the River along the eastern border include flood discharges, flood elevations, and the frequency of floods of varying magnitudes. They also include the daily or more frequent stage and discharge data for both the Mississippi River and the downstream gaging stations on Iowa tributaries for the period March-May 1965. Sufficient data are presented to permit studied for preparation of plans for protective works and plans for zoning or for flood plain regulation.

The "Prediflood" database of historical floods in Catalonia (NE Iberian Peninsula) AD 1035-2013, and its potential applications in flood analysis

NASA Astrophysics Data System (ADS)

Barriendos, M.; Ruiz-Bellet, J. L.; Tuset, J.; Mazón, J.; Balasch, J. C.; Pino, D.; Ayala, J. L.

2014-12-01

"Prediflood" is a database of historical floods that occurred in Catalonia (NE Iberian Peninsula), between the 11th century and the 21st century. More than 2700 flood cases are catalogued, and more than 1100 flood events. This database contains information acquired under modern historiographical criteria and it is, therefore, suitable for use in multidisciplinary flood analysis techniques, such as meteorological or hydraulic reconstructions.

Progressive incision of the Channeled Scablands by outburst floods.

PubMed

Larsen, Isaac J; Lamb, Michael P

2016-10-13

The surfaces of Earth and Mars contain large bedrock canyons that were carved by catastrophic outburst floods. Reconstructing the magnitude of these canyon-forming floods is essential for understanding the ways in which floods modify planetary surfaces, the hydrology of early Mars and abrupt changes in climate. Flood discharges are often estimated by assuming that the floods filled the canyons to their brims with water; however, an alternative hypothesis is that canyon morphology adjusts during incision such that bed shear stresses exceed the threshold for erosion by a small amount. Here we show that accounting for erosion thresholds during canyon incision results in near-constant discharges that are five- to ten-fold smaller than full-to-the-brim estimates for Moses Coulee, a canyon in the Channeled Scablands, which was carved during the Pleistocene by the catastrophic Missoula floods in eastern Washington, USA. The predicted discharges are consistent with flow-depth indicators from gravel bars within the canyon. In contrast, under the assumption that floods filled canyons to their brims, a large and monotonic increase in flood discharge is predicted as the canyon was progressively incised, which is at odds with the discharges expected for floods originating from glacial lake outbursts. These findings suggest that flood-carved landscapes in fractured rock might evolve to a threshold state for bedrock erosion, thus implying much lower flood discharges than previously thought.

Effect of depth of flooding on the rice water weevil, Lissorhoptrus oryzophilus, and yield of rice.

PubMed

Tindall, Kelly V; Bernhardt, John L; Stout, Michael J; Beighley, Donn H

2013-01-01

The rice water weevil, Lissorhoptrus oryzophilus (Kuschel) (Coleoptera: Curculionidae), is a semi-aquatic pest of rice and is the most destructive insect pest of rice in the United States. Adults oviposit after floods are established, and greenhouse studies have shown that plants exposed to deep floods have more eggs oviposited in leaf sheaths than plants exposed to a shallow flood. Experiments were conducted in three mid-southern states in the USA to determine if the depth of flooding would impact numbers of L. oryzophilus on rice plants under field conditions. Rice was flooded at depths of approximately 5 or 10 cm in Arkansas in 2007 and 2008 and Louisiana in 2008, and at depths between 0-20 cm in Missouri in 2008. Plants were sampled three and four weeks after floods were established in all locations, and also two weeks after flood in Missouri. On all sampling dates in four experiments over two years and at three field sites, fewer L. oryzophilus larvae were collected from rice in shallow-flooded plots than from deep-flooded plots. The number of L. oryzophilus was reduced by as much as 27% in shallow-flooded plots. However, the reduction in insect numbers did not translate to a significant increase in rice yield. We discuss how shallow floods could be used as a component of an integrated pest management program for L. oryzophilus.

Geospatial Tools for Prevention of Urban Floods Case Study: River of EL Maleh (city of Mohammedia - Morocco)

NASA Astrophysics Data System (ADS)

Chaabane, M. S.; Abouali, N.; Boumeaza, T.; Zahouily, M.

2017-11-01

Today, the prevention and the risk management occupy an important part of public policy activities and are considered as major components in the process of sustainable development of territories. Due to the expansion of IT processes, in particular the geomatics sciences, decision-makers are increasingly requesting for digital tools before, during and after the risks of natural disasters. Both, the geographic information system (GIS) and the remote sensing are considered as geospatial and fundamental tools which help to understand the evolution of risks, to analyze their temporality and to make the right decisions. The historic events (on 1996, 2002 and 2010) which struck the city of Mohammedia and having caused the consequent damage to vital infrastructure and private property, require a thorough and rational analyze to benefit from it and well manage the floods phenomena. This article present i) the contribution of the geospatial tools for the floods simulation of Oued of el Maleh city at various return periods. These tools allow the demarcation of flood-risk areas and so to make floods simulations in several scenarios (decadal flood, 20-year flood, 50-year flood, 100-year flood, 500-year flood & also millennial flood) and besides (ii) present a synthesis map combining the territorial stakes superposed on the flood scenarios at different periods of return.

Main drivers of flood-risk dynamics along the Po River

NASA Astrophysics Data System (ADS)

Domeneghetti, Alessio; Carisi, Francesca; Castellarin, Attilio; Brath, Armando

2017-04-01

The increasing frequency with which floods damages are recorded, or reported by media, strengthen the common perception that the flood risk is dramatically increasing in Europe and other areas of the world, due to a combination of different causes, among which climate change is often described as the major factor. However, there is a growing awareness of how anthropogenic pressures, such as uncontrolled urban and industrial expansion on flood-prone areas, may strongly impact the evolution of flood-risk in a given area, increasing potential flood damages and losses. Starting from these considerations, our study aims at shedding some light on the impact and relative importance of different factors controlling the flood risk. Focusing in particular on the middle-lower portion of the River Po, we analyze the evolution of flood hazard in the last half century referring to long streamflow series for different gauging stations located along the study reach ( 450 km), while the modification of anthropogenic pressure is evaluated by referring to land-use and demographic dynamics observed from 1950s. Our study proposes simplified flood-vulnerability indices to be used for large scale flood-risk assessments and, on the basis of these indices, (1) we assess the importance of the different elements contributing to the definition of flood risk and (2) represent the evolution of flood risk in time along the middle and lower portion of the River Po.

A non-stationary cost-benefit based bivariate extreme flood estimation approach

NASA Astrophysics Data System (ADS)

Qi, Wei; Liu, Junguo

2018-02-01

Cost-benefit analysis and flood frequency analysis have been integrated into a comprehensive framework to estimate cost effective design values. However, previous cost-benefit based extreme flood estimation is based on stationary assumptions and analyze dependent flood variables separately. A Non-Stationary Cost-Benefit based bivariate design flood estimation (NSCOBE) approach is developed in this study to investigate influence of non-stationarities in both the dependence of flood variables and the marginal distributions on extreme flood estimation. The dependence is modeled utilizing copula functions. Previous design flood selection criteria are not suitable for NSCOBE since they ignore time changing dependence of flood variables. Therefore, a risk calculation approach is proposed based on non-stationarities in both marginal probability distributions and copula functions. A case study with 54-year observed data is utilized to illustrate the application of NSCOBE. Results show NSCOBE can effectively integrate non-stationarities in both copula functions and marginal distributions into cost-benefit based design flood estimation. It is also found that there is a trade-off between maximum probability of exceedance calculated from copula functions and marginal distributions. This study for the first time provides a new approach towards a better understanding of influence of non-stationarities in both copula functions and marginal distributions on extreme flood estimation, and could be beneficial to cost-benefit based non-stationary bivariate design flood estimation across the world.

Improving Flash Flood Prediction in Multiple Environments

NASA Astrophysics Data System (ADS)

Broxton, P. D.; Troch, P. A.; Schaffner, M.; Unkrich, C.; Goodrich, D.; Wagener, T.; Yatheendradas, S.

2009-12-01

Flash flooding is a major concern in many fast responding headwater catchments . There are many efforts to model and to predict these flood events, though it is not currently possible to adequately predict the nature of flash flood events with a single model, and furthermore, many of these efforts do not even consider snow, which can, by itself, or in combination with rainfall events, cause destructive floods. The current research is aimed at broadening the applicability of flash flood modeling. Specifically, we will take a state of the art flash flood model that is designed to work with warm season precipitation in arid environments, the KINematic runoff and EROSion model (KINEROS2), and combine it with a continuous subsurface flow model and an energy balance snow model. This should improve its predictive capacity in humid environments where lateral subsurface flow significantly contributes to streamflow, and it will make possible the prediction of flooding events that involve rain-on-snow or rapid snowmelt. By modeling changes in the hydrologic state of a catchment before a flood begins, we can also better understand the factors or combination of factors that are necessary to produce large floods. Broadening the applicability of an already state of the art flash flood model, such as KINEROS2, is logical because flash floods can occur in all types of environments, and it may lead to better predictions, which are necessary to preserve life and property.

The 100-year flood seems to be changing. Can we really tell?

NASA Astrophysics Data System (ADS)

Ceres, R. L., Jr.; Forest, C. E.; Keller, K.

2017-12-01

Widespread flooding from Hurricane Harvey greatly exceeded the Federal Emergency Management Agency's 100-year flood levels. In the US, this flood level is often used as an important line of demarcation where areas above this level are considered safe, while areas below the line are at risk and require additional flood risk mitigation. In the wake of Harvey's damage, the US media has highlighted at least two important questions. First, has the 100-year flood level changed? Second, is the 100-year flood level a good metric for determining flood risk? To address the first question, we use an Observation System Simulation Experiment of storm surge flood levels and find that gradual changes to the 100-year storm surge level may not be reliably detected over the long lifespans expected of major flood risk mitigation strategies. Additionally, we find that common extreme value analysis models lead to biased results and additional uncertainty when incorrect assumptions are used for the underlying statistical model. These incorrect assumptions can lead to examples of negative learning. Addressing the second question, these findings further challenge the validity of using simple return levels such as the 100-year flood as a decision tool for assessing flood risk. These results indicate risk management strategies must account for such uncertainties to build resilient and robust planning tools that stakeholders desperately need.

Summary of floods in the United States during 1960

USGS Publications Warehouse

Rostvedt, J.O.

1965-01-01

This report describes the most outstanding floods in the United States during 1960. No major floods occurred during the year, although two floods caused severe damage the first in March and April in eastern Nebraska and adjacent areas, and the second in September in Puerto Rico.Unseasonal rains in mid-March caused extensive flooding in north-central Florida. Several thousand persons were evacuated from their homes, and damage to homes, roads, and crops was extensive.The most widespread flooding ever known in Nebraska occurred late in March and early in April as a result of rapid melting of a heavy snow cover. Most of the flood damage, estimated at about $3 million, was to roads and bridges. The flood area extended into South Dakota, Iowa, Kansas, Missouri, and Wisconsin.Snowmelt in April supplemented by rains and later heavy rains in early May caused severe flooding in northern Wisconsin and in Michigan Upper Peninsula.The most destructive flood of the year was in eastern Puerto Rico as the result of hurricane Donna. More than one hundred persons died, and considerably more than one hundred persons were injured; property damage was f.bout $7 million. Hurricane Donna also caused severe flooding as it passed over Florida and along the Atlantic coastline.In addition to these floods mentioned, 31 others of lesser magnitude were significant enough to report in this annual summary.

Predicting the microbial exposure risks in urban floods using GIS, building simulation, and microbial models.

PubMed

Taylor, Jonathon; Biddulph, Phillip; Davies, Michael; Lai, Ka man

2013-01-01

London is expected to experience more frequent periods of intense rainfall and tidal surges, leading to an increase in the risk of flooding. Damp and flooded dwellings can support microbial growth, including mould, bacteria, and protozoa, as well as persistence of flood-borne microorganisms. The amount of time flooded dwellings remain damp will depend on the duration and height of the flood, the contents of the flood water, the drying conditions, and the building construction, leading to particular properties and property types being prone to lingering damp and human pathogen growth or persistence. The impact of flooding on buildings can be simulated using Heat Air and Moisture (HAM) models of varying complexity in order to understand how water can be absorbed and dry out of the building structure. This paper describes the simulation of the drying of building archetypes representative of the English building stock using the EnergyPlus based tool 'UCL-HAMT' in order to determine the drying rates of different abandoned structures flooded to different heights and during different seasons. The results are mapped out using GIS in order to estimate the spatial risk across London in terms of comparative flood vulnerability, as well as for specific flood events. Areas of South and East London were found to be particularly vulnerable to long-term microbial exposure following major flood events. Copyright © 2012 Elsevier Ltd. All rights reserved.

Progressive incision of the Channeled Scablands by outburst floods

NASA Astrophysics Data System (ADS)

Larsen, Isaac J.; Lamb, Michael P.

2016-10-01

The surfaces of Earth and Mars contain large bedrock canyons that were carved by catastrophic outburst floods. Reconstructing the magnitude of these canyon-forming floods is essential for understanding the ways in which floods modify planetary surfaces, the hydrology of early Mars and abrupt changes in climate. Flood discharges are often estimated by assuming that the floods filled the canyons to their brims with water; however, an alternative hypothesis is that canyon morphology adjusts during incision such that bed shear stresses exceed the threshold for erosion by a small amount. Here we show that accounting for erosion thresholds during canyon incision results in near-constant discharges that are five- to ten-fold smaller than full-to-the-brim estimates for Moses Coulee, a canyon in the Channeled Scablands, which was carved during the Pleistocene by the catastrophic Missoula floods in eastern Washington, USA. The predicted discharges are consistent with flow-depth indicators from gravel bars within the canyon. In contrast, under the assumption that floods filled canyons to their brims, a large and monotonic increase in flood discharge is predicted as the canyon was progressively incised, which is at odds with the discharges expected for floods originating from glacial lake outbursts. These findings suggest that flood-carved landscapes in fractured rock might evolve to a threshold state for bedrock erosion, thus implying much lower flood discharges than previously thought.

The impact of bathymetry input on flood simulations

NASA Astrophysics Data System (ADS)

Khanam, M.; Cohen, S.

2017-12-01

Flood prediction and mitigation systems are inevitable for improving public safety and community resilience all over the worldwide. Hydraulic simulations of flood events are becoming an increasingly efficient tool for studying and predicting flood events and susceptibility. A consistent limitation of hydraulic simulations of riverine dynamics is the lack of information about river bathymetry as most terrain data record water surface elevation. The impact of this limitation on the accuracy on hydraulic simulations of flood has not been well studies over a large range of flood magnitude and modeling frameworks. Advancing our understanding of this topic is timely given emerging national and global efforts for developing automated flood predictions systems (e.g. NOAA National Water Center). Here we study the response of flood simulation to the incorporation of different bathymetry and floodplain surveillance source. Different hydraulic models are compared, Mike-Flood, a 2D hydrodynamic model, and GSSHA, a hydrology/hydraulics model. We test a hypothesis that the impact of inclusion/exclusion of bathymetry data on hydraulic model results will vary in its magnitude as a function of river size. This will allow researcher and stake holders more accurate predictions of flood events providing useful information that will help local communities in a vulnerable flood zone to mitigate flood hazards. Also, it will help to evaluate the accuracy and efficiency of different modeling frameworks and gage their dependency on detailed bathymetry input data.

Quantitative proteomics reveals the effect of protein glycosylation in soybean root under flooding stress

PubMed Central

Mustafa, Ghazala; Komatsu, Setsuko

2014-01-01

Flooding stress has a negative impact on soybean cultivation because it severely impairs growth and development. To understand the flooding responsive mechanism in early stage soybeans, a glycoproteomic technique was used. Two-day-old soybeans were treated with flooding for 2 days and roots were collected. Globally, the accumulation level of glycoproteins, as revealed by cross-reaction with concanavalin A decreased by 2 days of flooding stress. Glycoproteins were enriched from total protein extracts using concanavalin A lectin resin and analyzed using a gel-free proteomic technique. One-hundred eleven and 69 glycoproteins were identified without and with 2 days of flooding stress, respectively. Functional categorization of these identified glycoproteins indicated that the accumulation level of proteins related to protein degradation, cell wall, and glycolysis increased, while stress-related proteins decreased under flooding stress. Also the accumulation level of glycoproteins localized in the secretory pathway decreased under flooding stress. Out of 23 common glycoproteins between control and flooding conditions, peroxidases and glycosyl hydrolases were decreased by 2 days of flooding stress. mRNA expression levels of proteins in the endoplasmic reticulum and N-glycosylation related proteins were downregulated by flooding stress. These results suggest that flooding might negatively affect the process of N-glycosylation of proteins related to stress and protein degradation; however glycoproteins involved in glycolysis are activated. PMID:25477889

Effect of Depth of Flooding on the Rice Water Weevil, Lissorhoptrus oryzophilus, and Yield of Rice

PubMed Central

Tindall, Kelly V.; Bernhardt, John L.; Stout, Michael J.; Beighley, Donn H.

2013-01-01

The rice water weevil, Lissorhoptrus oryzophilus (Kuschel) (Coleoptera: Curculionidae), is a semi-aquatic pest of rice and is the most destructive insect pest of rice in the United States. Adults oviposit after floods are established, and greenhouse studies have shown that plants exposed to deep floods have more eggs oviposited in leaf sheaths than plants exposed to a shallow flood. Experiments were conducted in three mid-southern states in the USA to determine if the depth of flooding would impact numbers of L. oryzophilus on rice plants under field conditions. Rice was flooded at depths of approximately 5 or 10 cm in Arkansas in 2007 and 2008 and Louisiana in 2008, and at depths between 0–20 cm in Missouri in 2008. Plants were sampled three and four weeks after floods were established in all locations, and also two weeks after flood in Missouri. On all sampling dates in four experiments over two years and at three field sites, fewer L. oryzophilus larvae were collected from rice in shallow-flooded plots than from deep-flooded plots. The number of L. oryzophilus was reduced by as much as 27% in shallow-flooded plots. However, the reduction in insect numbers did not translate to a significant increase in rice yield. We discuss how shallow floods could be used as a component of an integrated pest management program for L. oryzophilus. PMID:23906324

An experimental system for flood risk forecasting at global scale

NASA Astrophysics Data System (ADS)

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.

Reinforcing flood-risk estimation.

PubMed

Reed, Duncan W

2002-07-15

Flood-frequency estimation is inherently uncertain. The practitioner applies a combination of gauged data, scientific method and hydrological judgement to derive a flood-frequency curve for a particular site. The resulting estimate can be thought fully satisfactory only if it is broadly consistent with all that is reliably known about the flood-frequency behaviour of the river. The paper takes as its main theme the search for information to strengthen a flood-risk estimate made from peak flows alone. Extra information comes in many forms, including documentary and monumental records of historical floods, and palaeological markers. Meteorological information is also useful, although rainfall rarity is difficult to assess objectively and can be a notoriously unreliable indicator of flood rarity. On highly permeable catchments, groundwater levels present additional data. Other types of information are relevant to judging hydrological similarity when the flood-frequency estimate derives from data pooled across several catchments. After highlighting information sources, the paper explores a second theme: that of consistency in flood-risk estimates. Following publication of the Flood estimation handbook, studies of flood risk are now using digital catchment data. Automated calculation methods allow estimates by standard methods to be mapped basin-wide, revealing anomalies at special sites such as river confluences. Such mapping presents collateral information of a new character. Can this be used to achieve flood-risk estimates that are coherent throughout a river basin?

Study of flood defense structural measures priorities using Compromise Programming technique

NASA Astrophysics Data System (ADS)

Lim, D.; Jeong, S.

2017-12-01

Recent climate change of global warming has led to the frequent occurrence of heavy regional rainfalls. As such, inundation vulnerability increases in urban areas with high population density due to the low runoff carrying capacity. This study selects a sample area (Janghang-eup, the Republic of Korea), which is one of the most vulnerable areas to flooding, analyzing the urban flood runoff model (XP-SWMM) and using the MCDM (Multi-Criteria Decision Making) technique to establish flood protection structural measures. To this end, we compare the alternatives and choose the optimal flood defense measure: our model is utilized with three flood prevention structural measures; (i) drainage pipe construction; (ii) water detention; and (iii) flood pumping station. Dividing the target area into three small basins, we propose flood evaluations for an inundation decrease by studying the flooded area, the maximum inundation depth, the damaged residential area, and the construction cost. In addition, Compromise Programming determines the priority of the alternatives. As a consequent, this study suggests flood pumping station for Zone 1 and drainage pipe construction for Zone 2 and Zone 3, respectively, as the optimal flood defense alternative. Keywords : MCDM; Compromise Programming; Urban Flood Prevention; This research was supported by a grant [MPSS-DP-2013-62] through the Disaster and Safety Management Institute funded by Ministry of Public Safety and Security of Korean government.

Flood inundation mapping in the Logone floodplain from multi temporal Landsat ETM+ imagery

NASA Astrophysics Data System (ADS)

Jung, H.; Alsdorf, D. E.; Moritz, M.; Lee, H.; Vassolo, S.

2011-12-01

Yearly flooding in the Logone floodplain makes an impact on agricultural, pastoral, and fishery systems in the Lake Chad Basin. Since the flooding extent and depth are highly variable, flood inundation mapping helps us make better use of water resources and prevent flood hazards in the Logone floodplain. The flood maps are generated from 33 multi temporal Landsat Enhanced Thematic Mapper Plus (ETM+) during three years 2006 to 2008. Flooded area is classified using a short-wave infrared band whereas open water is classified by Iterative Self-organizing Data Analysis (ISODATA) clustering. The maximum flooding extent in the study area increases up to ~5.8K km2 in late October 2008. The study also provides strong correlation of the flooding extents with water height variations in both the floodplain and the river based on a second polynomial regression model. The water heights are from ENIVSAT altimetry in the floodplain and gauge measurements in the river. Coefficients of determination between flooding extents and water height variations are greater than 0.91 with 4 to 36 days in phase lag. Floodwater drains back to the river and to the northeast during the recession period in December and January. The study supports understanding of the Logone floodplain dynamics in detail of spatial pattern and size of the flooding extent and assists the flood monitoring and prediction systems in the catchment.

Geographical information system (GIS) application for flood prediction at Sungai Sembrong

NASA Astrophysics Data System (ADS)

Kamin, Masiri; Ahmad, Nor Farah Atiqah; Razali, Siti Nooraiin Mohd; Hilaham, Mashuda Mohamad; Rahman, Mohamad Abdul; Ngadiman, Norhayati; Sahat, Suhaila

2017-10-01

The occurrence of flood is one of natural disaster that often beset Malaysia. The latest incident that happened in 2007 was the worst occurrence of floods ever be set in Johor. Reporting floods mainly focused on rising water rising levels, so about once a focus on the area of flood delineation. A study focused on the effectiveness of using Geographic Information System (GIS) to predict the flood by taking Sg. Sembrong, Batu Pahat, Johor as study area. This study combined hydrological model and water balance model in the display to show the expected flood area for future reference. The minimum, maximum and average rainfall data for January 2007 at Sg Sembrong were used in this study. The data shows that flood does not occurs at the minimum and average rainfall of 17.2mm and 2mm respectively. At maximum rainfall, 203mm, shows the flood area was 9983 hectares with the highest level of the water depth was 2m. The result showed that the combination of hydrological models and water balance model in GIS is very suitable to be used as a tool to obtain preliminary information on flood immediately. Besides that, GIS system is a very powerful tool used in hydrology engineering to help the engineer and planner to imagine the real situation of flood events, doing flood analysis, problem solving and provide a rational, accurate and efficient decision making.

Flood Inundation Mapping in the Logone Floodplain from Multi Temporal Landsat ETM+Imagery

NASA Technical Reports Server (NTRS)

Jung, Hahn Chul; Alsdorf, Douglas E.; Moritz, Mark; Lee, Hyongki; Vassolo, Sara

2011-01-01

Yearly flooding in the Logone floodplain makes an impact on agricultural, pastoral, and fishery systems in the Lake Chad Basin. Since the flooding extent and depth are highly variable, flood inundation mapping helps us make better use of water resources and prevent flood hazards in the Logone floodplain. The flood maps are generated from 33 multi temporal Landsat Enhanced Thematic Mapper Plus (ETM+) during three years 2006 to 2008. Flooded area is classified using a short-wave infrared band whereas open water is classified by Iterative Self-organizing Data Analysis (ISODATA) clustering. The maximum flooding extent in the study area increases up to approximately 5.8K km2 in late October 2008. The study also provides strong correlation of the flooding extents with water height variations in both the floodplain and the river based on a second polynomial regression model. The water heights are from ENIVSAT altimetry in the floodplain and gauge measurements in the river. Coefficients of determination between flooding extents and water height variations are greater than 0.91 with 4 to 36 days in phase lag. Floodwater drains back to the river and to the northeast during the recession period in December and January. The study supports understanding of the Logone floodplain dynamics in detail of spatial pattern and size of the flooding extent and assists the flood monitoring and prediction systems in the catchment.

Flood regimes in a changing world: What do we know?

NASA Astrophysics Data System (ADS)

Bloeschl, G.

2015-12-01

There has been a surprisingly large number of major floods in the last years around the world which suggests that floods may have increased and will continue to increase in the next decades. However, the realism of such changes is still hotly discussed in the literature. In this presentation I will argue that a fresh look is needed at the flood change problem in terms of the causal factors including river training, land use changes and climate variability. Analysing spatial patterns of dynamic flood characteristics helps learn form the rich diversity of flood processes across the landscape. I will present a number of examples across Europe to illustrate the range of flood generation processes and the causal factors of changes in the flood regime. On the basis of these examples, I will demonstrate how comparative hydrology can assist in learning from the differences of flood characteristics between catchments both for present and future conditions. Focus on the interactions of the natural and human water system will be instrumental in making meaningful statements about future floods in a changing world. References Hall et al. (2014) Understanding Flood Regime Changes in Europe: A state of the art assessment. Hydrol. Earth Sys. Sc., 18, 2735-2772. Blöschl et al. (2015) Increasing river floods: fiction or reality? Wiley Interdisciplinary Reviews: Water. doi: 10.1002/wat2.1079

Insurance against climate change and flood risk: Insurability and decision processes of insurers

NASA Astrophysics Data System (ADS)

Hung, Hung-Chih; Hung, Jia-Yi

2016-04-01

1. Background Major portions of the Asia-Pacific region is facing escalating exposure and vulnerability to climate change and flood-related extremes. This highlights an arduous challenge for public agencies to improve existing risk management strategies. Conventionally, governmental funding was majorly responsible and accountable for disaster loss compensation in the developing countries in Asia, such as Taiwan. This is often criticized as an ineffective and inefficient measure of dealing with flood risk. Flood insurance is one option within the toolkit of risk-sharing arrangement and adaptation strategy to flood risk. However, there are numerous potential barriers for insurance companies to cover flood damage, which would cause the flood risk is regarded as uninsurable. This study thus aims to examine attitudes within the insurers about the viability of flood insurance, the decision-making processes of pricing flood insurance and their determinants, as well as to examine potential solutions to encourage flood insurance. 2. Methods and data Using expected-utility theory, an insurance agent-based decision-making model was developed to examine the insurers' attitudes towards the insurability of flood risk, and to scrutinize the factors that influence their decisions on flood insurance premium-setting. This model particularly focuses on how insurers price insurance when they face either uncertainty or ambiguity about the probability and loss of a particular flood event occurring. This study considers the factors that are expected to affect insures' decisions on underwriting and pricing insurance are their risk perception, attitudes towards flood insurance, governmental measures (e.g., land-use planning, building codes, risk communication), expected probabilities and losses of devastating flooding events, as well as insurance companies' attributes. To elicit insurers' utilities about premium-setting for insurance coverage, the 'certainty equivalent,' 'probability equivalent,' and 'gamble tradeoff' methods were used. We then synthesized a Tobit and an OLS regression analysis to identify and examine the determinants of insurers' decisions on insurability and pricing for flood risk. Furthermore, the data were collected through a questionnaire survey, which was conducted with the assistance from the Non-life Underwriters Society, Taiwan and the Actuarial Institute, Taiwan. After pretesting, questionnaires were mailed to 410 randomly chosen commercial property-and-casualty insurance firms' actuaries and underwriters. The final sample consisted of 179 questionnaires for a 43.8% response rate. 3. Results Results of the questionnaire survey reveal that flood risk tends to be more uninsurable when there is ambiguity regarding the probability of a particular flood event loss. The presence of insurers' risk aversion appears to be robust. Insurers would charge a significantly higher price for a flood insurance policy than normal property insurance. The findings also show that the insurers who perceived higher levels of flood risk, or/and had a company with smaller size or higher financial leverage, would trigger a higher premium for flood insurance. Governmental risk management strategies, such as land-use planning, building codes, flood-hazard zone regulations, also played a prominent role in enhancing insurability and decreasing insurance premium. Therefore, appropriate incentives should be combined with better public risk communication and mitigation strategies to stimulate insurance coverage in reducing flood loss.

44 CFR 10.14 - Flood plains and wetlands.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood plains and wetlands. 10... Flood plains and wetlands. For any action taken by FEMA in a flood plain or wetland, the provisions of... Executive Order 11988, Flood Plain Management, and Executive Order 11990, Protection of Wetlands (44 CFR...

12 CFR 22.3 - Requirement to purchase flood insurance where available.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Requirement to purchase flood insurance where... IN AREAS HAVING SPECIAL FLOOD HAZARDS § 22.3 Requirement to purchase flood insurance where available... building or mobile home and any personal property securing the loan is covered by flood insurance for the...

12 CFR 22.7 - Forced placement of flood insurance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Forced placement of flood insurance. 22.7... HAVING SPECIAL FLOOD HAZARDS § 22.7 Forced placement of flood insurance. If a bank, or a servicer acting... or mobile home and any personal property securing the designated loan is not covered by flood...

12 CFR 614.4940 - Required use of standard flood hazard determination form.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Required use of standard flood hazard... LOAN POLICIES AND OPERATIONS Flood Insurance Requirements § 614.4940 Required use of standard flood hazard determination form. (a) Use of form. System institutions must use the standard flood hazard...

12 CFR 572.3 - Requirement to purchase flood insurance where available.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Requirement to purchase flood insurance where... LOANS IN AREAS HAVING SPECIAL FLOOD HAZARDS § 572.3 Requirement to purchase flood insurance where... loan unless the building or mobile home and any personal property securing the loan is covered by flood...

12 CFR 572.6 - Required use of standard flood hazard determination form.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 5 2010-01-01 2010-01-01 false Required use of standard flood hazard... TREASURY LOANS IN AREAS HAVING SPECIAL FLOOD HAZARDS § 572.6 Required use of standard flood hazard determination form. (a) Use of form. A savings association shall use the standard flood hazard determination...

12 CFR 614.4930 - Requirement to purchase flood insurance where available.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Requirement to purchase flood insurance where... POLICIES AND OPERATIONS Flood Insurance Requirements § 614.4930 Requirement to purchase flood insurance... flood insurance for the term of the loan. The amount of insurance must be at least equal to the...

Flood disturbance in a forested mountain landscape: interactions of land use and floods.

Treesearch

F.J. Swanson; S.L. Johnson; S.V. Gregory; S.A. Acker

1998-01-01

Recent flooding in the Pacific Northwest vividly illustrates the complexity of watershed and ecosystem responses to floods, especially in steep forest landscapes. Flooding involves a sequence of interactions that begins with climatic drivers. These drivers, generally rain and snowmelt, interact with landscape conditions, such as vegetation pattern and topography, to...

Floods in the Rock River basin, Iowa

USGS Publications Warehouse

Heinitz, Albert J.

1973-01-01

Flood profiles for the Rock River include those for the 1962, 1964, 1965, 1969, and the computed 25- and 50-year floods. On the Little Rock River and Otter Creek, profiles include those for the 1969 flood and the computed 25- and 50-year floods. Low-water profiles are shown for all reaches.

44 CFR 60.12 - Flood plain management criteria for State-owned properties in special hazard areas.

Code of Federal Regulations, 2012 CFR

2012-10-01

... MITIGATION National Flood Insurance Program CRITERIA FOR LAND MANAGEMENT AND USE Requirements for State Flood Plain Management Regulations § 60.12 Flood plain management criteria for State-owned properties in... 44 Emergency Management and Assistance 1 2012-10-01 2011-10-01 true Flood plain management...

44 CFR 60.12 - Flood plain management criteria for State-owned properties in special hazard areas.

Code of Federal Regulations, 2014 CFR

2014-10-01

... MITIGATION National Flood Insurance Program CRITERIA FOR LAND MANAGEMENT AND USE Requirements for State Flood Plain Management Regulations § 60.12 Flood plain management criteria for State-owned properties in... 44 Emergency Management and Assistance 1 2014-10-01 2014-10-01 false Flood plain management...

44 CFR 60.12 - Flood plain management criteria for State-owned properties in special hazard areas.

Code of Federal Regulations, 2013 CFR

2013-10-01

... MITIGATION National Flood Insurance Program CRITERIA FOR LAND MANAGEMENT AND USE Requirements for State Flood Plain Management Regulations § 60.12 Flood plain management criteria for State-owned properties in... 44 Emergency Management and Assistance 1 2013-10-01 2013-10-01 false Flood plain management...

44 CFR 60.12 - Flood plain management criteria for State-owned properties in special hazard areas.

Code of Federal Regulations, 2010 CFR

2010-10-01

... MITIGATION National Flood Insurance Program CRITERIA FOR LAND MANAGEMENT AND USE Requirements for State Flood Plain Management Regulations § 60.12 Flood plain management criteria for State-owned properties in... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Flood plain management...

44 CFR 60.12 - Flood plain management criteria for State-owned properties in special hazard areas.

Code of Federal Regulations, 2011 CFR

2011-10-01

... MITIGATION National Flood Insurance Program CRITERIA FOR LAND MANAGEMENT AND USE Requirements for State Flood Plain Management Regulations § 60.12 Flood plain management criteria for State-owned properties in... 44 Emergency Management and Assistance 1 2011-10-01 2011-10-01 false Flood plain management...

Quantifying the Impact of Floods on Bacillary Dysentery in Dalian City, China, From 2004 to 2010.

PubMed

Xu, Xin; Ding, Guoyong; Zhang, Ying; Liu, Zhidong; Liu, Qiyong; Jiang, Baofa

2017-04-01

Studies quantifying relationships between floods and diarrheal diseases have mainly been conducted in low-latitude regions. It's therefore increasingly important to examine these relationships in midlatitude regions, where they may have significant public health implications. This study aimed to examine the association between floods and bacillary dysentery in the city of Dalian, China. A generalized additive mixed model was applied to examine the association between floods and bacillary dysentery. The relative risk (RR) of flood impact on bacillary dysentery was estimated. A total of 18,976 cases of bacillary dysentery were reported in Dalian during the study period. Two weeks' lagged effect was detected from the impact of floods on bacillary dysentery. The RR of flood impact on bacillary dysentery was 1.17 (95% CI: 1.03-1.33). Floods have significantly increased the risk of bacillary dysentery in Dalian. More studies should focus on the association between floods and infectious diseases in different regions. Our findings have significant implications for managing the negative health impact of floods in the midlatitude region of China. (Disaster Med Public Health Preparedness. 2017;11:190-195).

Germany wide seasonal flood risk analysis for agricultural crops

NASA Astrophysics Data System (ADS)

Klaus, Stefan; Kreibich, Heidi; Kuhlmann, Bernd; Merz, Bruno; Schröter, Kai

2016-04-01

In recent years, large-scale flood risk analysis and mapping has gained attention. Regional to national risk assessments are needed, for example, for national risk policy developments, for large-scale disaster management planning and in the (re-)insurance industry. Despite increasing requests for comprehensive risk assessments some sectors have not received much scientific attention, one of these is the agricultural sector. In contrast to other sectors, agricultural crop losses depend strongly on the season. Also flood probability shows seasonal variation. Thus, the temporal superposition of high flood susceptibility of crops and high flood probability plays an important role for agricultural flood risk. To investigate this interrelation and provide a large-scale overview of agricultural flood risk in Germany, an agricultural crop loss model is used for crop susceptibility analyses and Germany wide seasonal flood-frequency analyses are undertaken to derive seasonal flood patterns. As a result, a Germany wide map of agricultural flood risk is shown as well as the crop type most at risk in a specific region. The risk maps may provide guidance for federal state-wide coordinated designation of retention areas.

Satellites, tweets, forecasts: the future of flood disaster management?

NASA Astrophysics Data System (ADS)

Dottori, Francesco; Kalas, Milan; Lorini, Valerio; Wania, Annett; Pappenberger, Florian; Salamon, Peter; Ramos, Maria Helena; Cloke, Hannah; Castillo, Carlos

2017-04-01

Floods have devastating effects on lives and livelihoods around the world. Structural flood defence measures such as dikes and dams can help protect people. However, it is the emerging science and technologies for flood disaster management and preparedness, such as increasingly accurate flood forecasting systems, high-resolution satellite monitoring, rapid risk mapping, and the unique strength of social media information and crowdsourcing, that are most promising for reducing the impacts of flooding. Here, we describe an innovative framework which integrates in real-time two components of the Copernicus Emergency mapping services, namely the European Flood Awareness System and the satellite-based Rapid Mapping, with new procedures for rapid risk assessment and social media and news monitoring. The integrated framework enables improved flood impact forecast, thanks to the real-time integration of forecasting and monitoring components, and increases the timeliness and efficiency of satellite mapping, with the aim of capturing flood peaks and following the evolution of flooding processes. Thanks to the proposed framework, emergency responders will have access to a broad range of timely and accurate information for more effective and robust planning, decision-making, and resource allocation.

The efficiency of asset management strategies to reduce urban flood risk.

PubMed

ten Veldhuis, J A E; Clemens, F H L R

2011-01-01

In this study, three asset management strategies were compared with respect to their efficiency to reduce flood risk. Data from call centres at two municipalities were used to quantify urban flood risks associated with three causes of urban flooding: gully pot blockage, sewer pipe blockage and sewer overloading. The efficiency of three flood reduction strategies was assessed based on their effect on the causes contributing to flood risk. The sensitivity of the results to uncertainty in the data source, citizens' calls, was analysed through incorporation of uncertainty ranges taken from customer complaint literature. Based on the available data it could be shown that increasing gully pot blockage is the most efficient action to reduce flood risk, given data uncertainty. If differences between cause incidences are large, as in the presented case study, call data are sufficient to decide how flood risk can be most efficiently reduced. According to the results of this analysis, enlargement of sewer pipes is not an efficient strategy to reduce flood risk, because flood risk associated with sewer overloading is small compared to other failure mechanisms.

Insurability and mitigation of flood losses in private households in Germany.

PubMed

Thieken, Annegret H; Petrow, Theresia; Kreibich, Heidi; Merz, Bruno

2006-04-01

In Germany, flood insurance is provided by private insurers as a supplement to building or contents insurance. This article presents the results of a survey of insurance companies with regard to eligibility conditions for flood insurance changes after August 2002, when a severe flood caused 1.8 billion euro of insured losses in the Elbe and the Danube catchment areas, and the general role of insurance in flood risk management in Germany. Besides insurance coverage, governmental funding and public donations played an important role in loss compensation after the August 2002 flood. Therefore, this article also analyzes flood loss compensation, risk awareness, and mitigation in insured and uninsured private households. Insured households received loss compensation earlier. They also showed slightly better risk awareness and mitigation strategies. Appropriate incentives should be combined with flood insurance in order to strengthen future private flood loss mitigation. However, there is some evidence that the surveyed insurance companies do little to encourage precautionary measures. To overcome this problem, flood hazards and mitigation strategies should be better communicated to both insurance companies and property owners.

Social vulnerability and the natural and built environment: a model of flood casualties in Texas.

PubMed

Zahran, Sammy; Brody, Samuel D; Peacock, Walter Gillis; Vedlitz, Arnold; Grover, Himanshu

2008-12-01

Studies on the impacts of hurricanes, tropical storms, and tornados indicate that poor communities of colour suffer disproportionately in human death and injury.(2) Few quantitative studies have been conducted on the degree to which flood events affect socially vulnerable populations. We address this research void by analysing 832 countywide flood events in Texas from 1997-2001. Specifically, we examine whether geographic localities characterised by high percentages of socially vulnerable populations experience significantly more casualties due to flood events, adjusting for characteristics of the natural and built environment. Zero-inflated negative binomial regression models indicate that the odds of a flood casualty increase with the level of precipitation on the day of a flood event, flood duration, property damage caused by the flood, population density, and the presence of socially vulnerable populations. Odds decrease with the number of dams, the level of precipitation on the day before a recorded flood event, and the extent to which localities have enacted flood mitigation strategies. The study concludes with comments on hazard-resilient communities and protection of casualty-prone populations.

Fault tree analysis for urban flooding.

PubMed

ten Veldhuis, J A E; Clemens, F H L R; van Gelder, P H A J M

2009-01-01

Traditional methods to evaluate flood risk generally focus on heavy storm events as the principal cause of flooding. Conversely, fault tree analysis is a technique that aims at modelling all potential causes of flooding. It quantifies both overall flood probability and relative contributions of individual causes of flooding. This paper presents a fault model for urban flooding and an application to the case of Haarlem, a city of 147,000 inhabitants. Data from a complaint register, rainfall gauges and hydrodynamic model calculations are used to quantify probabilities of basic events in the fault tree. This results in a flood probability of 0.78/week for Haarlem. It is shown that gully pot blockages contribute to 79% of flood incidents, whereas storm events contribute only 5%. This implies that for this case more efficient gully pot cleaning is a more effective strategy to reduce flood probability than enlarging drainage system capacity. Whether this is also the most cost-effective strategy can only be decided after risk assessment has been complemented with a quantification of consequences of both types of events. To do this will be the next step in this study.

Magnitude and frequency of flooding on the Myakka River, Southwest Florida

USGS Publications Warehouse

Hammett, K.M.; Turner, J.F.; Murphy, W.R.

1978-01-01

Increasing numbers of urban and agricultural developments are being located on waterfront property in the Myakka River flood plain in southwest Florida. Under natural conditions, a large depression, Tatum Sawgrass, was available as a flood storage area in the upper Myakka River basin. Construction of dikes across the lower part of Tatum Sawgrass has restricted use of the depression for temporary storage of Myakka River flood water overflow, and has resulted in increased flood-peak discharges and flood heights in downstream reaches of the Myakka River. The difference between natural and diked condition flood-peak discharges and flood heights is presented to illustrate the effects of the dikes. Flood-peak discharges, water-surface elevations and flood profiles also are provided for diked conditions. Analytical procedures used to evaluate diking effects are described in detail. The study reach includes Myakka River main stem upstream from U.S. Highway 41, near Myakka Shores in Sarasota County, to State Road 70 near Myakka City in Manatee County (including Tatum Sawgrass and Clay Gully), and Blackburn Canal from Venice By-Way to Myakka River. (Woodard-USGS)

Prehistoric floods on the Tennessee River—Assessing the use of stratigraphic records of past floods for improved flood-frequency analysis

USGS Publications Warehouse

Harden, Tessa M.; O'Connor, Jim E.

2017-06-14

Stratigraphic analysis, coupled with geochronologic techniques, indicates that a rich history of large Tennessee River floods is preserved in the Tennessee River Gorge area. Deposits of flood sediment from the 1867 peak discharge of record (460,000 cubic feet per second at Chattanooga, Tennessee) are preserved at many locations throughout the study area at sites with flood-sediment accumulation. Small exposures at two boulder overhangs reveal evidence of three to four other floods similar in size, or larger, than the 1867 flood in the last 3,000 years—one possibly as much or more than 50 percent larger. Records of floods also are preserved in stratigraphic sections at the mouth of the gorge at Williams Island and near Eaves Ferry, about 70 river miles upstream of the gorge. These stratigraphic records may extend as far back as about 9,000 years ago, giving a long history of Tennessee River floods. Although more evidence is needed to confirm these findings, a more in-depth comprehensive paleoflood study is feasible for the Tennessee River.

Proteomic and Biochemical Analyses of the Cotyledon and Root of Flooding-Stressed Soybean Plants

PubMed Central

Komatsu, Setsuko; Makino, Takahiro; Yasue, Hiroshi

2013-01-01

Background Flooding significantly reduces the growth and grain yield of soybean plants. Proteomic and biochemical techniques were used to determine whether the function of cotyledon and root is altered in soybean under flooding stress. Results Two-day-old soybean plants were flooded for 2 days, after which the proteins from root and cotyledon were extracted for proteomic analysis. In response to flooding stress, the abundance of 73 and 28 proteins was significantly altered in the root and cotyledon, respectively. The accumulation of only one protein, 70 kDa heat shock protein (HSP70) (Glyma17g08020.1), increased in both organs following flooding. The ratio of protein abundance of HSP70 and biophoton emission in the cotyledon was higher than those detected in the root under flooding stress. Computed tomography and elemental analyses revealed that flooding stress decreases the number of calcium oxalate crystal the cotyledon, indicating calcium ion was elevated in the cotyledon under flooding stress. Conclusion These results suggest that calcium might play one role through HSP70 in the cotyledon under flooding stress. PMID:23799004

Flood-Exposure Is Associated with Higher Prevalence of Child Undernutrition in Rural Eastern India

PubMed Central

Rodriguez-Llanes, Jose Manuel; Ranjan-Dash, Shishir; Mukhopadhyay, Alok; Guha-Sapir, Debarati

2016-01-01

Background: Child undernutrition and flooding are highly prevalent public health issues in Asia, yet epidemiological studies investigating this association are lacking. Methods: To investigate to what extent floods exacerbate poor nutritional status in children and identify most vulnerable groups, we conducted a population-based survey of children aged 6–59 months inhabiting flooded and non-flooded communities of the Jagatsinghpur district, Odisha (India), one year after large floods in 2008. Anthropometric measurements on 879 children and child, parental and household level variables were collected through face-to-face interviews in September 2009. The association between flooding and the prevalence of wasting, stunting and underweight was examined using weighted multivariate logistic regression for children inhabiting communities exposed solely to floods in 2008 and those communities repeatedly flooded (2006 and 2008) controlling for parental education and other relevant variables. We examined the influence of age on this association. Propensity score matching was conducted to test the robustness of our findings. Results: The prevalence of wasting among children flooded in 2006 and 2008 was 51.6%, 41.4% in those flooded only in 2008, and 21.2% in children inhabiting non-flooded communities. Adjusting by confounders, the increased prevalence relative to non-flooded children in the exposed groups were 2.30 (adjusted prevalence ratio (aPR); 95% CI: 1.86, 2.85) and 1.94 (95% CI: 1.43, 2.63), respectively. Among repeatedly flooded communities, cases of severe wasting in children were 3.37 times more prevalent than for children inhabiting in those non-flooded (95% CI: 2.34, 4.86) and nearly twice more prevalent relative to those flooded only once. Those children younger than one year during previous floods in 2006 showed the largest difference in prevalence of wasting compared to their non-flooded counterparts (aPR: 4.01; 95% CI: 1.51, 10.63). Results were robust to alternative adjusted models and in propensity score matching analyses. For similar analyses, no significant associations were found for child stunting, and more moderate effects were observed in the case of child underweight. Conclusions: Particularly in low-resource or subsistence-farming rural settings, long-lasting nutritional response in the aftermath of floods should be seriously considered to counteract the long-term nutritional effects on children, particularly infants, and include their mothers on whom they are dependent. The systematic monitoring of nutritional status in these groups might help to tailor efficient responses in each particular context. PMID:26861372

Damage-reducing measures to manage flood risks in a changing climate

NASA Astrophysics Data System (ADS)

Kreibich, Heidi; Bubeck, Philip; Van Vliet, Mathijs; De Moel, Hans

2014-05-01

Damage due to floods has increased during the last few decades, and further increases are expected in several regions due to climate change and a growing vulnerability. To address the projected increase in flood risk, a combination of structural and non-structural flood risk mitigation measures is considered as a promising adaptation strategy. Such a combination takes into account that flood defence systems may fail, and prepare for unexpected crisis situations via land-use planning, building construction, evacuation and disaster response. Non-structural flood risk mitigation measures like shielding with water shutters or sand bags, building fortification or safeguarding of hazardous substances are often voluntary: they demand self-dependent action by the population at risk (Bubeck et al. 2012; 2013). It is believed that these measures are especially effective in areas with frequent flood events and low flood water levels, but some types of measures showed a significant damage-reducing effect also during extreme flood events, such as the Elbe River flood in August 2002 in Germany (Kreibich et al. 2005; 2011). Despite the growing importance of damage-reducing measures, information is still scarce about factors that motivate people to undertake such measures, the state of implementation of various non-structural measures in different countries and their damage reducing effects. Thus, we collected information and undertook an international review about this topic in the framework of the Dutch KfC project "Climate proof flood risk management". The contribution will present an overview about the available information on damage-reducing measures and draw conclusions for practical flood risk management in a changing climate. References: Bubeck, P., Botzen, W. J. W., Suu, L. T. T., Aerts, J. C. J. H. (2012): Do flood risk perceptions provide useful insights for flood risk management? Findings from central Vietnam. Journal of Flood Risk Management, 5, 4, 295-302 Bubeck, P., Botzen, W. J. W., Kreibich, H., Aerts, J. C. J. H. (2013) Detailed insights into the influence of flood-coping appraisals on mitigation behaviour. Global Environmental Change. DOI:10.1016/j.gloenvcha.2013.05.009. Kreibich, H., Thieken, A. H., Petrow, T., Müller, M., Merz, B. (2005): Flood loss reduction of private households due to building precautionary measures - Lessons Learned from the Elbe flood in August 2002. NHESS, 5, 1, 117-126. Kreibich, H., Christenberger, S., Schwarze, R. (2011) Economic motivation of households to undertake private precautionary measures against floods. NHESS, 11, 2, 309-321.

Flood-Exposure is Associated with Higher Prevalence of Child Undernutrition in Rural Eastern India.

PubMed

Rodriguez-Llanes, Jose Manuel; Ranjan-Dash, Shishir; Mukhopadhyay, Alok; Guha-Sapir, Debarati

2016-02-06

Child undernutrition and flooding are highly prevalent public health issues in Asia, yet epidemiological studies investigating this association are lacking. To investigate to what extent floods exacerbate poor nutritional status in children and identify most vulnerable groups, we conducted a population-based survey of children aged 6-59 months inhabiting flooded and non-flooded communities of the Jagatsinghpur district, Odisha (India), one year after large floods in 2008. Anthropometric measurements on 879 children and child, parental and household level variables were collected through face-to-face interviews in September 2009. The association between flooding and the prevalence of wasting, stunting and underweight was examined using weighted multivariate logistic regression for children inhabiting communities exposed solely to floods in 2008 and those communities repeatedly flooded (2006 and 2008) controlling for parental education and other relevant variables. We examined the influence of age on this association. Propensity score matching was conducted to test the robustness of our findings. The prevalence of wasting among children flooded in 2006 and 2008 was 51.6%, 41.4% in those flooded only in 2008, and 21.2% in children inhabiting non-flooded communities. Adjusting by confounders, the increased prevalence relative to non-flooded children in the exposed groups were 2.30 (adjusted prevalence ratio (aPR); 95% CI: 1.86, 2.85) and 1.94 (95% CI: 1.43, 2.63), respectively. Among repeatedly flooded communities, cases of severe wasting in children were 3.37 times more prevalent than for children inhabiting in those non-flooded (95% CI: 2.34, 4.86) and nearly twice more prevalent relative to those flooded only once. Those children younger than one year during previous floods in 2006 showed the largest difference in prevalence of wasting compared to their non-flooded counterparts (aPR: 4.01; 95% CI: 1.51, 10.63). RESULTS were robust to alternative adjusted models and in propensity score matching analyses. For similar analyses, no significant associations were found for child stunting, and more moderate effects were observed in the case of child underweight. Particularly in low-resource or subsistence-farming rural settings, long-lasting nutritional response in the aftermath of floods should be seriously considered to counteract the long-term nutritional effects on children, particularly infants, and include their mothers on whom they are dependent. The systematic monitoring of nutritional status in these groups might help to tailor efficient responses in each particular context.

Flood-inundation maps for the West Branch Delaware River, Delhi, New York, 2012

USGS Publications Warehouse

Coon, William F.; Breaker, Brian K.

2012-01-01

Digital flood-inundation maps for a 5-mile reach of the West Branch Delaware River through the Village and part of the Town of Delhi, New York, were created by the U.S. Geological Survey (USGS) in cooperation with the Village of Delhi, the Delaware County Soil and Water Conservation District, and the Delaware County Planning Department. The inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science Web site at http://water.usgs.gov/osw/flood_inundation/ and the Federal Flood Inundation Mapper Web site at http://wim.usgs.gov/FIMI/FloodInundationMapper.html, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) referenced to the USGS streamgage at West Branch Delaware River upstream from Delhi, N.Y. (station number 01421900). In this study, flood profiles were computed for the stream reach by means of a one-dimensional step-backwater model that had been used to produce the flood insurance rate maps for the most recent flood insurance study for the Town and Village of Delhi. This hydraulic model was used to compute 10 water-surface profiles for flood stages at 1-foot (ft) intervals referenced to the streamgage datum and ranging from 7 ft or near bankfull to 16 ft, which exceeds the stages that correspond to both the estimated 0.2-percent annual-exceedance-probability flood (500-year recurrence interval flood) and the maximum recorded peak flow. The simulated water-surface profiles were then combined with a geographic information system (GIS) digital elevation model, which was derived from Light Detection and Ranging (LiDAR) data with a 1.2-ft (0.61-ft root mean squared error) vertical accuracy and 3.3-ft (1-meter) horizontal resolution, to delineate the area flooded at each water level. A map that was produced using this method to delineate the inundated area for the flood that occurred on August 28, 2011, agreed well with highwater marks that had been located in the field using a global positioning system. The availability of the 10 flood-inundation maps on the USGS Flood Inundation Mapping Science Web site, along with Internet information regarding current stage from the USGS streamgage, will provide emergency management personnel and residents with information that is critical for flood-response activities, such as evacuations and road closures, as well as for post-flood recovery efforts.

44 CFR 65.3 - Requirement to submit new technical data.

Code of Federal Regulations, 2012 CFR

2012-10-01

... base flood elevations may increase or decrease resulting from physical changes affecting flooding... physical changes affecting flooding conditions, risk premium rates and flood plain management requirements...

44 CFR 65.3 - Requirement to submit new technical data.

Code of Federal Regulations, 2013 CFR

2013-10-01

... base flood elevations may increase or decrease resulting from physical changes affecting flooding... physical changes affecting flooding conditions, risk premium rates and flood plain management requirements...

44 CFR 65.3 - Requirement to submit new technical data.

Code of Federal Regulations, 2014 CFR

2014-10-01

... base flood elevations may increase or decrease resulting from physical changes affecting flooding... physical changes affecting flooding conditions, risk premium rates and flood plain management requirements...

Flood of May 5 and 6, 1981, Mobile, Alabama

USGS Publications Warehouse

Ming, C.O.; Nelson, G.H.

1981-01-01

Heavy and intense rainfall in the late evening and early morning hours, May 5 and 6, 1981, caused widespread flooding along streams and low-lying areas in the port city of Mobile, Ala. More than 12 inches of rain fell between 6 p.m. May 5, and 3 a.m. May 6. Damage caused by flooding was estimated by the Mobile Department of Public Works to be millions of dollars. Maximum water surface elevations on streams in the area were 2 to 3 feet higher than those that occurred during a similar flood in April 1980. The approximate extent of flooding delineated on maps using flood profiles obtained by field surveys will provide a basis for formulating effective flood plain zoning that could minimize existing and future flood problems. (USGS)

Flood characteristics of the Haor area in Bangladesh

NASA Astrophysics Data System (ADS)

Suman, Asadusjjaman; Bhattacharya, Biswa

2013-04-01

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. Bangladesh is a country, which is frequently suffering from flooding. The current research is conducted in the framework of a project, which focuses on the flooding issues in the Haor region in the north-east of Bangladesh. A haor is a saucer-shaped depression, which is used during the dry period (December to mid-May) for agriculture and as a fishery during the wet period (June-November), and thereby presents a very interesting socio-economic perspective of flood risk management. Pre-monsoon flooding till mid-May causes agricultural loss and lot of distress whereas monsoon flooding brings benefits. The area is bordering India, thereby presenting trans-boundary issues as well, and is fed by some flashy Indian catchments. The area is drained mainly through 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 impact of climate changes. A 1D2D model, with one-dimensional model for the rivers (based on MIKE 11 modelling tool from Danish Hydraulic Institute) and a two-dimensional model (based on MIKE 21 modelling tool from Danish Hydraulic Institute) for the haors were developed. While the 1D model was calibrated well the calibration of 2D model was an issue due to the non-availability of measured data. The flood extent of the 2D model was calibrated to a limited extent with the remote sensing images. In order to keep the computing load within feasible limits the most-flood prone area of the region, often loosely defined as the deeply flooded area, consisting of about 15 haors was chosen as the model domain. Based on the simulation results corresponding to the 2004 pre-monsoon and monsoon floods the flood propagation within the model domain was studied and the characteristics of rivers (and areas) with fast and slow responses to flood waves were identified. The following three characteristics of a flood hydrograph were considered: i) rising curve gradient ii) flood magnitude ratio (in terms of the average discharge) and iii) time to peak. The parameters were normalised in a scale of 0 to 1 and summed up to compute the normalised flood index. The normalised flood index is an aggregated indicator based on the flood hydrograph characteristics. The spatial and temporal distribution of the index have been studied. Initial studies on climate change indicate substantial impact on the region. Future studies will evolve around making use of remotely sensed data in improving the understanding of the hydro-meteorological characterisation of the area. Keywords: flood characteristics, flood index, Haor, Bangladesh.

Using ensemble rainfall predictions in a countrywide flood forecasting model in Scotland

NASA Astrophysics Data System (ADS)

Cranston, M. D.; Maxey, R.; Tavendale, A. C. W.; Buchanan, P.

2012-04-01

Improving flood predictions for all sources of flooding is at the centre of flood risk management policy in Scotland. With the introduction of the Flood Risk Management (Scotland) Act providing a new statutory basis for SEPA's flood warning responsibilities, the pressures on delivering hydrological science developments in support of this legislation has increased. Specifically, flood forecasting capabilities need to develop in support of the need to reduce the impact of flooding through the provision of actively disseminated, reliable and timely flood warnings. Flood forecasting in Scotland has developed significantly in recent years (Cranston and Tavendale, 2012). The development of hydrological models to predict flooding at a catchment scale has relied upon the application of rainfall runoff models utilising raingauge, radar and quantitative precipitation forecasts in the short lead time (less than 6 hours). Single or deterministic forecasts based on highly uncertain rainfall predictions have led to the greatest operational difficulties when communicating flood risk with emergency responders, therefore the emergence of probability-based estimates offers the greatest opportunity for managing uncertain predictions. This paper presents operational application of a physical-conceptual distributed hydrological model on a countrywide basis across Scotland. Developed by CEH Wallingford for SEPA in 2011, Grid-to-Grid (G2G) principally runs in deterministic mode and employs radar and raingauge estimates of rainfall together with weather model predictions to produce forecast river flows, as gridded time-series at a resolution of 1km and for up to 5 days ahead (Cranston, et al., 2012). However the G2G model is now being run operationally using ensemble predictions of rainfall from the MOGREPS-R system to provide probabilistic flood forecasts. By presenting a range of flood predictions on a national scale through this approach, hydrologists are now able to consider an objective measure of the likelihood of flooding impacts to help with risk based emergency communication.

Quality control of the RMS US flood model

NASA Astrophysics Data System (ADS)

Jankowfsky, Sonja; Hilberts, Arno; Mortgat, Chris; Li, Shuangcai; Rafique, Farhat; Rajesh, Edida; Xu, Na; Mei, Yi; Tillmanns, Stephan; Yang, Yang; Tian, Ye; Mathur, Prince; Kulkarni, Anand; Kumaresh, Bharadwaj Anna; Chaudhuri, Chiranjib; Saini, Vishal

2016-04-01

The RMS US flood model predicts the flood risk in the US with a 30 m resolution for different return periods. The model is designed for the insurance industry to estimate the cost of flood risk for a given location. Different statistical, hydrological and hydraulic models are combined to develop the flood maps for different return periods. A rainfall-runoff and routing model, calibrated with observed discharge data, is run with 10 000 years of stochastic simulated precipitation to create time series of discharge and surface runoff. The 100, 250 and 500 year events are extracted from these time series as forcing for a two-dimensional pluvial and fluvial inundation model. The coupling of all the different models which are run on the large area of the US implies a certain amount of uncertainty. Therefore, special attention is paid to the final quality control of the flood maps. First of all, a thorough quality analysis of the Digital Terrain model and the river network was done, as the final quality of the flood maps depends heavily on the DTM quality. Secondly, the simulated 100 year discharge in the major river network (600 000 km) is compared to the 100 year discharge derived using extreme value distribution of all USGS gauges with more than 20 years of peak values (around 11 000 gauges). Thirdly, for each gauge the modelled flood depth is compared to the depth derived from the USGS rating curves. Fourthly, the modelled flood depth is compared to the base flood elevation given in the FEMA flood maps. Fifthly, the flood extent is compared to the FEMA flood extent. Then, for historic events we compare flood extents and flood depths at given locations. Finally, all the data and spatial layers are uploaded on geoserver to facilitate the manual investigation of outliers. The feedback from the quality control is used to improve the model and estimate its uncertainty.

High resolution mapping of flood hazard for South Korea

NASA Astrophysics Data System (ADS)

Ghosh, Sourima; Nzerem, Kechi; Zovi, Francesco; Li, Shuangcai; Mei, Yi; Assteerawatt, Anongnart; Hilberts, Arno; Tillmanns, Stephan; Mitas, Christos

2015-04-01

Floods are one of primary natural hazards that affect South Korea. During the past 15 years, catastrophic flood events which mainly have occurred during the rainy and typhoon seasons - especially under condition where soils are already saturated, have triggered substantial property damage with an average annual loss of around US1.2 billion (determined from WAter Management Information System's flood damage database for years 2002-2011) in South Korea. According to Seoul Metropolitan Government, over 16,000 households in the capital city Seoul were inundated during 2010 flood events. More than 10,000 households in Seoul were apparently flooded during one major flood event due to torrential rain in July 2011. Recently in August 2014, a serious flood event due to heavy rainfall hit the Busan region in the south east of South Korea. Addressing the growing needs, RMS has recently released country-wide high resolution combined flood return period maps for post-drainage local "pluvial" inundation and undefended large-scale "fluvial" inundation to aid the government and the insurance industry in the evaluation of comprehensive flood risk. RMS has developed a flood hazard model for South Korea to generate inundation depths and extents for a range of flood return periods. The model is initiated with 30 years of historical meteorological forcing data and calibrated to daily observations at over 100 river gauges across the country. Simulations of hydrologic processes are subsequently performed based on a 2000 year set of stochastic forcing. Floodplain inundation processes are modelled by numerically solving the shallow water equations using finite volume method on GPUs. Taking into account the existing stormwater drainage standards, economic exposure densities, etc., reasonable flood maps are created from inundation model output. Final hazard maps at one arcsec grid resolution can be the basis for both evaluating and managing flood risk, its economic impacts, and insured flood losses in South Korea.

The influence of major dams on hydrology through the drainage network of the Sacramento River basin, California

USGS Publications Warehouse

Singer, M.B.

2007-01-01

This paper reports basinwide patterns of hydrograph alteration via statistical and graphical analysis from a network of long-term streamflow gauges located various distances downstream of major dams and confluences in the Sacramento River basin in California, USA. Streamflow data from 10 gauging stations downstream of major dams were divided into hydrologic series corresponding to the periods before and after dam construction. Pre- and post-dam flows were compared with respect to hydrograph characteristics representing frequency, magnitude and shape: annual flood peak, annual flow trough, annual flood volume, time to flood peak, flood drawdown time and interarrival time. The use of such a suite of characteristics within a statistical and graphical framework allows for generalising distinct strategies of flood control operation that can be identified without any a priori knowledge of operations rules. Dam operation is highly dependent on the ratio of reservoir capacity to annual flood volume (impounded runoff index). Dams with high values of this index generally completely cut off flood peaks thus reducing time to peak, drawdown time and annual flood volume. Those with low values conduct early and late flow releases to extend the hydrograph, increasing time to peak, drawdown time and annual flood volume. The analyses reveal minimal flood control benefits from foothill dams in the lower Sacramento River (i.e. dissipation of the down-valley flood control signal). The lower part of the basin is instead reliant on a weir and bypass system to control lowland flooding. Data from a control gauge (i.e. with no upstream dams) suggest a background signature of global climate change expressed as shortened flood hydrograph falling limbs and lengthened flood interarrival times at low exceedence probabilities. This research has implications for flood control, water resource management, aquatic and riparian ecosystems and for rehabilitation strategies involving flow alteration and/or manipulation of sediment supplies. Copyright ?? 2006 John Wiley & Sons, Ltd.

A new concept to study the effect of climate change on different flood types

NASA Astrophysics Data System (ADS)

Nissen, Katrin; Nied, Manuela; Pardowitz, Tobias; Ulbrich, Uwe; Merz, Bruno

2014-05-01

Flooding is triggered by the interaction of various processes. Especially important are the hydrological conditions prior to the event (e.g. soil saturation, snow cover) and the meteorological conditions during flood development (e.g. rainfall, temperature). Depending on these (pre-) conditions different flood types may develop such as long-rain floods, short-rain floods, flash floods, snowmelt floods and rain-on-snow floods. A new concept taking these factors into account is introduced and applied to flooding in the Elbe River basin. During the period September 1957 to August 2002, 82 flood events are identified and classified according to their flood type. The hydrological and meteorological conditions at each day during the analysis period are detemined. In case of the hydrological conditions, a soil moisture pattern classification is carried out. Soil moisture is simulated with a rainfall-runoff model driven by atmospheric observations. Days of similar soil moisture patterns are identified by a principle component analysis and a subsequent cluster analysis on the leading principal components. The meteorological conditions are identified by applying a cluster analysis to the geopotential height, temperature and humidity fields of the ERA40 reanalysis data set using the SANDRA cluster algorithm. We are able to identify specific pattern combinations of hydrological pre-conditions and meteorological conditions which favour different flood types. Based on these results it is possible to analyse the effect of climate change on different flood types. As an example we show first results obtained using an ensemble of climate scenario simulations of ECHAM5 MPIOM model, taking only the changes in the meteorological conditions into account. According to the simulations, the frequency of the meteorological patterns favouring long-rain, short-rain and flash floods will not change significantly under future climate conditions. A significant increase is, however, predicted for the amount of precipitation associated with many of the relevant meteorological patterns. The increase varies between 12 and 67% depending on the weather pattern.

Paleohydrologic techniques used to define the spatial occurrence of floods

USGS Publications Warehouse

Jarrett, R.D.

1990-01-01

Defining the cause and spatial characteristics of floods may be difficult because of limited streamflow and precipitation data. New paleohydrologic techniques that incorporate information from geomorphic, sedimentologic, and botanic studies provide important supplemental information to define homogeneous hydrologic regions. These techniques also help to define the spatial structure of rainstorms and floods and improve regional flood-frequency estimates. The occurrence and the non-occurrence of paleohydrologic evidence of floods, such as flood bars, alluvial fans, and tree scars, provide valuable hydrologic information. The paleohydrologic research to define the spatial characteristics of floods improves the understanding of flood hydrometeorology. This research was used to define the areal extent and contributing drainage area of flash floods in Colorado. Also, paleohydrologic evidence was used to define the spatial boundaries for the Colorado foothills region in terms of the meteorologic cause of flooding and elevation. In general, above 2300 m, peak flows are caused by snowmelt. Below 2300 m, peak flows primarily are caused by rainfall. The foothills region has an upper elevation limit of about 2300 m and a lower elevation limit of about 1500 m. Regional flood-frequency estimates that incorporate the paleohydrologic information indicate that the Big Thompson River flash flood of 1976 had a recurrence interval of approximately 10,000 years. This contrasts markedly with 100 to 300 years determined by using conventional hydrologic analyses. Flood-discharge estimates based on rainfall-runoff methods in the foothills of Colorado result in larger values than those estimated with regional flood-frequency relations, which are based on long-term streamflow data. Preliminary hydrologic and paleohydrologic research indicates that intense rainfall does not occur at higher elevations in other Rocky Mountain states and that the highest elevations for rainfall-producing floods vary by latitude. The study results have implications for floodplain management and design of hydraulic structures in the mountains of Colorado and other Rocky Mountain States. ?? 1990.

Climate change impacts on flood risk and asset damages within mapped 100-year floodplains of the contiguous United States

NASA Astrophysics Data System (ADS)

Wobus, Cameron; Gutmann, Ethan; Jones, Russell; Rissing, Matthew; Mizukami, Naoki; Lorie, Mark; Mahoney, Hardee; Wood, Andrew W.; Mills, David; Martinich, Jeremy

2017-12-01

A growing body of work suggests that the extreme weather events that drive inland flooding are likely to increase in frequency and magnitude in a warming climate, thus potentially increasing flood damages in the future. We use hydrologic projections based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) to estimate changes in the frequency of modeled 1 % annual exceedance probability (1 % AEP, or 100-year) flood events at 57 116 stream reaches across the contiguous United States (CONUS). We link these flood projections to a database of assets within mapped flood hazard zones to model changes in inland flooding damages throughout the CONUS over the remainder of the 21st century. Our model generates early 21st century flood damages that reasonably approximate the range of historical observations and trajectories of future damages that vary substantially depending on the greenhouse gas (GHG) emissions pathway. The difference in modeled flood damages between higher and lower emissions pathways approaches USD 4 billion per year by 2100 (in undiscounted 2014 dollars), suggesting that aggressive GHG emissions reductions could generate significant monetary benefits over the long term in terms of reduced flood damages. Although the downscaled hydrologic data we used have been applied to flood impacts studies elsewhere, this research expands on earlier work to quantify changes in flood risk by linking future flood exposure to assets and damages on a national scale. Our approach relies on a series of simplifications that could ultimately affect damage estimates (e.g., use of statistical downscaling, reliance on a nationwide hydrologic model, and linking damage estimates only to 1 % AEP floods). Although future work is needed to test the sensitivity of our results to these methodological choices, our results indicate that monetary damages from inland flooding could be significantly reduced through substantial GHG mitigation.

A new automatic synthetic aperture radar-based flood mapping application hosted on the European Space Agency's Grid Processing of Demand Fast Access to Imagery environment

NASA Astrophysics Data System (ADS)

Matgen, Patrick; Giustarini, Laura; Hostache, Renaud

2012-10-01

This paper introduces an automatic flood mapping application that is hosted on the Grid Processing on Demand (GPOD) Fast Access to Imagery (Faire) environment of the European Space Agency. The main objective of the online application is to deliver operationally flooded areas using both recent and historical acquisitions of SAR data. Having as a short-term target the flooding-related exploitation of data generated by the upcoming ESA SENTINEL-1 SAR mission, the flood mapping application consists of two building blocks: i) a set of query tools for selecting the "crisis image" and the optimal corresponding "reference image" from the G-POD archive and ii) an algorithm for extracting flooded areas via change detection using the previously selected "crisis image" and "reference image". Stakeholders in flood management and service providers are able to log onto the flood mapping application to get support for the retrieval, from the rolling archive, of the most appropriate reference image. Potential users will also be able to apply the implemented flood delineation algorithm. The latter combines histogram thresholding, region growing and change detection as an approach enabling the automatic, objective and reliable flood extent extraction from SAR images. Both algorithms are computationally efficient and operate with minimum data requirements. The case study of the high magnitude flooding event that occurred in July 2007 on the Severn River, UK, and that was observed with a moderateresolution SAR sensor as well as airborne photography highlights the performance of the proposed online application. The flood mapping application on G-POD can be used sporadically, i.e. whenever a major flood event occurs and there is a demand for SAR-based flood extent maps. In the long term, a potential extension of the application could consist in systematically extracting flooded areas from all SAR images acquired on a daily, weekly or monthly basis.

Bayesian Non-Stationary Flood Frequency Estimation at Ungauged Basins Using Climate Information and a Scaling Model

NASA Astrophysics Data System (ADS)

Lima, C. H.; Lall, U.

2010-12-01

Flood frequency statistical analysis most often relies on stationary assumptions, where distribution moments (e.g. mean, standard deviation) and associated flood quantiles do not change over time. In this sense, one expects that flood magnitudes and their frequency of occurrence will remain constant as observed in the historical information. However, evidence of inter-annual and decadal climate variability and anthropogenic change as well as an apparent increase in the number and magnitude of flood events across the globe have made the stationary assumption questionable. Here, we show how to estimate flood quantiles (e.g. 100-year flood) at ungauged basins without needing to consider stationarity. A statistical model based on the well known flow-area scaling law is proposed to estimate flood flows at ungauged basins. The slope and intercept scaling law coefficients are assumed time varying and a hierarchical Bayesian model is used to include climate information and reduce parameter uncertainties. Cross-validated results from 34 streamflow gauges located in a nested Basin in Brazil show that the proposed model is able to estimate flood quantiles at ungauged basins with remarkable skills compared with data based estimates using the full record. The model as developed in this work is also able to simulate sequences of flood flows considering global climate changes provided an appropriate climate index developed from the General Circulation Model is used as a predictor. The time varying flood frequency estimates can be used for pricing insurance models, and in a forecast mode for preparations for flooding, and finally, for timing infrastructure investments and location. Non-stationary 95% interval estimation for the 100-year Flood (shaded gray region) and 95% interval for the 100-year flood estimated from data (horizontal dashed and solid lines). The average distribution of the 100-year flood is shown in green in the right side.

Improving Flood Risk Management for California's Central Valley: How the State Developed a Toolbox for Large, System-wide Studies

NASA Astrophysics Data System (ADS)

Pingel, N.; Liang, Y.; Bindra, A.

2016-12-01

More than 1 million Californians live and work in the floodplains of the Sacramento-San Joaquin Valley where flood risks are among the highest in the nation. In response to this threat to people, property and the environment, the Department of Water Resources (DWR) has been called to action to improve flood risk management. This has transpired through significant advances in development of flood information and tools, analysis, and planning. Senate Bill 5 directed DWR to prepare the Central Valley Flood Protection Plan (CVFPP) and update it every 5 years. A key component of this aggressive planning approach is answering the question: What is the current flood risk, and how would proposed improvements change flood risk throughout the system? Answering this question is a substantial challenge due to the size and complexity of the watershed and flood control system. The watershed is roughly 42,000 sq mi, and flows are controlled by numerous reservoirs, bypasses, and levees. To overcome this challenge, the State invested in development of a comprehensive analysis "tool box" through various DWR programs. Development of the tool box included: collection of hydro-meteorological, topographic, geotechnical, and economic data; development of rainfall-runoff, reservoir operation, hydraulic routing, and flood risk analysis models; and development of specialized applications and computing schemes to accelerate the analysis. With this toolbox, DWR is analyzing flood hazard, flood control system performance, exposure and vulnerability of people and property to flooding, consequence of flooding for specific events, and finally flood risk for a range of CVFPP alternatives. Based on the results, DWR will put forward a State Recommended Plan in the 2017 CVFPP. Further, the value of the analysis tool box extends beyond the CVFPP. It will serve as a foundation for other flood studies for years to come and has already been successfully applied for inundation mapping to support emergency response, reservoir operation analysis, and others.

Life cycle stage and water depth affect flooding-induced adventitious root formation in the terrestrial species Solanum dulcamara

PubMed Central

Zhang, Qian; Visser, Eric J. W.; de Kroon, Hans; Huber, Heidrun

2015-01-01

Background and Aims Flooding can occur at any stage of the life cycle of a plant, but often adaptive responses of plants are only studied at a single developmental stage. It may be anticipated that juvenile plants may respond differently from mature plants, as the amount of stored resources may differ and morphological changes can be constrained. Moreover, different water depths may require different strategies to cope with the flooding stress, the expression of which may also depend on developmental stage. This study investigated whether flooding-induced adventitious root formation and plant growth were affected by flooding depth in Solanum dulcamara plants at different developmental stages. Methods Juvenile plants without pre-formed adventitious root primordia and mature plants with primordia were subjected to shallow flooding or deep flooding for 5 weeks. Plant growth and the timing of adventitious root formation were monitored during the flooding treatments. Key Results Adventitious root formation in response to shallow flooding was significantly constrained in juvenile S. dulcamara plants compared with mature plants, and was delayed by deep flooding compared with shallow flooding. Complete submergence suppressed adventitious root formation until up to 2 weeks after shoots restored contact with the atmosphere. Independent of developmental stage, a strong positive correlation was found between adventitious root formation and total biomass accumulation during shallow flooding. Conclusions The potential to deploy an escape strategy (i.e. adventitious root formation) may change throughout a plant’s life cycle, and is largely dependent on flooding depth. Adaptive responses at a given stage of the life cycle thus do not necessarily predict how the plant responds to flooding in another growth stage. As variation in adventitious root formation also correlates with finally attained biomass, this variation may form the basis for variation in resistance to shallow flooding among plants. PMID:26105188

Life cycle stage and water depth affect flooding-induced adventitious root formation in the terrestrial species Solanum dulcamara.

PubMed

Zhang, Qian; Visser, Eric J W; de Kroon, Hans; Huber, Heidrun

2015-08-01

Flooding can occur at any stage of the life cycle of a plant, but often adaptive responses of plants are only studied at a single developmental stage. It may be anticipated that juvenile plants may respond differently from mature plants, as the amount of stored resources may differ and morphological changes can be constrained. Moreover, different water depths may require different strategies to cope with the flooding stress, the expression of which may also depend on developmental stage. This study investigated whether flooding-induced adventitious root formation and plant growth were affected by flooding depth in Solanum dulcamara plants at different developmental stages. Juvenile plants without pre-formed adventitious root primordia and mature plants with primordia were subjected to shallow flooding or deep flooding for 5 weeks. Plant growth and the timing of adventitious root formation were monitored during the flooding treatments. Adventitious root formation in response to shallow flooding was significantly constrained in juvenile S. dulcamara plants compared with mature plants, and was delayed by deep flooding compared with shallow flooding. Complete submergence suppressed adventitious root formation until up to 2 weeks after shoots restored contact with the atmosphere. Independent of developmental stage, a strong positive correlation was found between adventitious root formation and total biomass accumulation during shallow flooding. The potential to deploy an escape strategy (i.e. adventitious root formation) may change throughout a plant's life cycle, and is largely dependent on flooding depth. Adaptive responses at a given stage of the life cycle thus do not necessarily predict how the plant responds to flooding in another growth stage. As variation in adventitious root formation also correlates with finally attained biomass, this variation may form the basis for variation in resistance to shallow flooding among plants. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Analysis of floods, including the tropical storm Irene inundation, of the Ottauquechee River in Woodstock, Bridgewater, and Killington and of Reservoir Brook in Bridgewater and Plymouth, Vermont

USGS Publications Warehouse

Flynn, Robert H.

2014-01-01

In addition to the two digital flood inundation maps, flood profiles were created that depict the study reach flood elevation of tropical storm Irene of August 2011 and the 10-, 2-, 1-, and 0.2-percent AEP floods, also known as the 10-, 50-, 100-, and 500-year floods, respectively. The 10-, 2-, 1-, and 0.2-percent AEP flood discharges were determined using annual peak flow data from the USGS Ottauquechee River near West Bridgewater, Vt. streamgage (station 01150900). Flood profiles were computed for the Ottauquechee River and Reservoir Brook by means of a one-dimensional step-backwater model. The model was calibrated using documented high-water marks of the peak of the tropical storm Irene flood of August 2011 as well as stage discharge data as determined for USGS Ottauquechee River near West Bridgewater, Vt. streamgage (station 01150900). The simulated water-surface profiles were combined with a digital elevation model within a geographic information system to delineate the areas flooded during tropical storm Irene and for the 1-percent AEP water-surface profile. The digital elevation model data were derived from light detection and ranging (lidar) data obtained for a 3,281-foot (1,000-meter) corridor along the Ottauquechee River study reach and were augmented with 33-foot (10- meter) contour interval data in the modeled flood-inundation areas outside the lidar corridor. The 33-foot (10-meter) contour interval USGS 15-minute quadrangle topographic digital raster graphics map used to augment lidar data was produced at a scale of 1:24,000. The digital flood inundation maps and flood profiles along with information regarding current stage from USGS streamgages on the Internet provide emergency management personnel and residents with information that is critical for flood response activities, such as evacuations and road closures, as well as for post-flood recovery efforts.

Modeled changes in 100 year Flood Risk and Asset Damages within Mapped Floodplains of the Contiguous United States

NASA Astrophysics Data System (ADS)

Wobus, C. W.; Gutmann, E. D.; Jones, R.; Rissing, M.; Mizukami, N.; Lorie, M.; Mahoney, H.; Wood, A.; Mills, D.; Martinich, J.

2017-12-01

A growing body of recent work suggests that the extreme weather events that drive inland flooding are likely to increase in frequency and magnitude in a warming climate, thus increasing monetary damages from flooding in the future. We use hydrologic projections based on the Coupled Model Intercomparison Project Phase 5 (CMIP5) to estimate changes in the frequency of modeled 1% annual exceedance probability flood events at 57,116 locations across the contiguous United States (CONUS). We link these flood projections to a database of assets within mapped flood hazard zones to model changes in inland flooding damages throughout the CONUS over the remainder of the 21st century, under two greenhouse gas (GHG) emissions scenarios. Our model generates early 21st century flood damages that reasonably approximate the range of historical observations, and trajectories of future damages that vary substantially depending on the GHG emissions pathway. The difference in modeled flood damages between higher and lower emissions pathways approaches $4 billion per year by 2100 (in undiscounted 2014 dollars), suggesting that aggressive GHG emissions reductions could generate significant monetary benefits over the long-term in terms of reduced flood risk. Although the downscaled hydrologic data we used have been applied to flood impacts studies elsewhere, this research expands on earlier work to quantify changes in flood risk by linking future flood exposure to assets and damages at a national scale. Our approach relies on a series of simplifications that could ultimately affect damage estimates (e.g., use of statistical downscaling, reliance on a nationwide hydrologic model, and linking damage estimates only to 1% AEP floods). Although future work is needed to test the sensitivity of our results to these methodological choices, our results suggest that monetary damages from inland flooding could be substantially reduced through more aggressive GHG mitigation policies.

Floods at Mount Clemens, Michigan

USGS Publications Warehouse

Wiitala, S.W.; Ash, Arlington D.

1962-01-01

The approximate areas inundated during the flood of April 5-6, 1947, by Clinton River, North Branch and Middle Branch of Clinton River, and Harrington Drain, in Clinton Township, Macomb County, Mich., are shown on a topographic map base to record the flood hazard in graphical form. The flood of April 1947 is the highest known since 1934 and probably since 1902. Greater floods are possible, but no attempt was made to define their probable overflow limits.The Clinton River Cut-Off Canal, a flood-relief channel which diverts flow directly into Lake St. Clair from a point about 1500 feet downstream from Gratiot Avenue (about 9 miles upstream from the mouth) has been in operation since October 1951. The approximate limits of overflow that would results from a flood equivalent in discharge to that of April 1947, and occurring with the Cut-Off Canal in operation, are also shown. Although the Cut-Off Canal may reduce the frequency and depth of flooding it will not necessarily eliminate future flooding in the area. Improvements and additions to the drainage systems in the basin, expanding urbanization, new highways, and other cultural changes may influence the inundation pattern of future floods.The preparation of this flood inundation map was financed through a cooperative agreement between Clinton Township, Macomb County, Mich., and the U.S. Geological Survey.Backwater curves used to define the profile for a hypothetical flood on the Clinton River downstream from Moravian Drive, equivalent in discharge to the 1947 flood, but occurring with the present Cut-Off Canal in operation; flood stage established at the gaging station on Clinton River at Mount Clemens; and supplementary floodmark elevations were furnished by the Corps of Engineers.Bench-mark elevations and field survey data, used in the analysis of floods on Harrington Drain, were furnished by the Macomb County Drain Commission.

Projections of hepatitis A virus infection associated with flood events by 2020 and 2030 in Anhui Province, China

NASA Astrophysics Data System (ADS)

Gao, Lu; Zhang, Ying; Ding, Guoyong; Liu, Qiyong; Wang, Changke; Jiang, Baofa

2016-12-01

Assessing and responding to health risk of climate change is important because of its impact on the natural and societal ecosystems. More frequent and severe flood events will occur in China due to climate change. Given that population is projected to increase, more people will be vulnerable to flood events, which may lead to an increased incidence of HAV infection in the future. This population-based study is going to project the future health burden of HAV infection associated with flood events in Huai River Basin of China. The study area covered four cities of Anhui province in China, where flood events were frequent. Time-series adjusted Poisson regression model was developed to quantify the risks of flood events on HAV infection based on the number of daily cases during summer seasons from 2005 to 2010, controlling for other meteorological variables. Projections of HAV infection in 2020 and 2030 were estimated based on the scenarios of flood events and demographic data. Poisson regression model suggested that compared with the periods without flood events, the risks of severe flood events for HAV infection were significant (OR = 1.28, 95 % CI 1.05-1.55), while risks were not significant from moderate flood events (OR = 1.16, 95 % CI 0.72-1.87) and mild flood events (OR = 1.14, 95 % CI 0.87-1.48). Using the 2010 baseline data and the flood event scenarios (one severe flood event), increased incidence of HAV infection were estimated to be between 0.126/105 and 0.127/105 for 2020. Similarly, the increased HAV infection incidence for 2030 was projected to be between 0.382/105 and 0.399/105. Our study has, for the first time, quantified the increased incidence of HAV infection that will result from flood events in Anhui, China, in 2020 and 2030. The results have implications for public health preparation for developing public health responses to reduce HAV infection during future flood events.

Modeling tools for the assessment of microbiological risks during floods: a review

NASA Astrophysics Data System (ADS)

Collender, Philip; Yang, Wen; Stieglitz, Marc; Remais, Justin

2015-04-01

Floods are a major, recurring source of harm to global economies and public health. Projected increases in the frequency and intensity of heavy precipitation events under future climate change, coupled with continued urbanization in areas with high risk of floods, may exacerbate future impacts of flooding. Improved flood risk management is essential to support global development, poverty reduction and public health, and is likely to be a crucial aspect of climate change adaptation. Importantly, floods can facilitate the transmission of waterborne pathogens by changing social conditions (overcrowding among displaced populations, interruption of public health services), imposing physical challenges to infrastructure (sewerage overflow, reduced capacity to treat drinking water), and altering fate and transport of pathogens (transport into waterways from overland flow, resuspension of settled contaminants) during and after flood conditions. Hydrological and hydrodynamic models are capable of generating quantitative characterizations of microbiological risks associated with flooding, while accounting for these diverse and at times competing physical and biological processes. Despite a few applications of such models to the quantification of microbiological risks associated with floods, there exists limited guidance as to the relative capabilities, and limitations, of existing modeling platforms when used for this purpose. Here, we review 17 commonly used flood and water quality modeling tools that have demonstrated or implicit capabilities of mechanistically representing and quantifying microbial risk during flood conditions. We compare models with respect to their capabilities of generating outputs that describe physical and microbial conditions during floods, such as concentration or load of non-cohesive sediments or pathogens, and the dynamics of high flow conditions. Recommendations are presented for the application of specific modeling tools for assessing particular flood-related microbial risks, and model improvements are suggested that may better characterize key microbial risks during flood events. The state of current tools are assessed in the context of a changing climate where the frequency, intensity and duration of flooding are shifting in some areas.

Flood-inundation maps for the Hoosic River, North Adams and Williamstown, Massachusetts, from the confluence with the North Branch Hoosic River to the Vermont State line

USGS Publications Warehouse

Lombard, Pamela J.; Bent, Gardner C.

2015-01-01

The availability of the flood-inundation maps, combined with information regarding current (near real-time) stage from USGS streamgage Hoosic River near Williamstown, and forecasted flood stages from the National Weather Service Advanced Hydrologic Prediction Service will provide emergency management personnel and residents with information that is critical for flood response activities such as evacuations and road closures, and post-flood recovery efforts. The flood-inundation maps are nonregulatory, but provide Federal, State, and local agencies and the public with estimates of the potential extent of flooding during selected peak-flow events.

Integrating adaptive behaviour in large-scale flood risk assessments: an Agent-Based Modelling approach

NASA Astrophysics Data System (ADS)

Haer, Toon; Aerts, Jeroen

2015-04-01

Between 1998 and 2009, Europe suffered over 213 major damaging floods, causing 1126 deaths, displacing around half a million people. In this period, floods caused at least 52 billion euro in insured economic losses making floods the most costly natural hazard faced in Europe. In many low-lying areas, the main strategy to cope with floods is to reduce the risk of the hazard through flood defence structures, like dikes and levees. However, it is suggested that part of the responsibility for flood protection needs to shift to households and businesses in areas at risk, and that governments and insurers can effectively stimulate the implementation of individual protective measures. However, adaptive behaviour towards flood risk reduction and the interaction between the government, insurers, and individuals has hardly been studied in large-scale flood risk assessments. In this study, an European Agent-Based Model is developed including agent representatives for the administrative stakeholders of European Member states, insurers and reinsurers markets, and individuals following complex behaviour models. The Agent-Based Modelling approach allows for an in-depth analysis of the interaction between heterogeneous autonomous agents and the resulting (non-)adaptive behaviour. Existing flood damage models are part of the European Agent-Based Model to allow for a dynamic response of both the agents and the environment to changing flood risk and protective efforts. By following an Agent-Based Modelling approach this study is a first contribution to overcome the limitations of traditional large-scale flood risk models in which the influence of individual adaptive behaviour towards flood risk reduction is often lacking.

The Effects of Floods on the Incidence of Bacillary Dysentery in Baise (Guangxi Province, China) from 2004 to 2012.

PubMed

Liu, Xuena; Liu, Zhidong; Zhang, Ying; Jiang, Baofa

2017-02-12

Research shows potential effects of floods on intestinal infections. Baise, a city in Guangxi Province (China) had experienced several floods between 2004 and 2012 due to heavy and constant precipitation. This study aimed to examine the relationship between floods and the incidence of bacillary dysentery in Baise. A mixed generalized additive model and Spearman correlation were applied to analyze the relationship between monthly incidence of bacillary dysentery and 14 flood events with two severity levels. Data collected from 2004 to 2010 were utilized to estimate the parameters, whereas data from 2011 to 2012 were used to validate the model. There were in total 9255 cases of bacillary dysentery included in our analyses. According to the mixed generalized additive model, the relative risks (RR) of moderate and severe floods on the incidence of bacillary dysentery were 1.40 (95% confidence interval (CI): 1.16-1.69) and 1.78 (95% CI: 1.61-1.97), respectively. The regression analysis also indicated that the flood duration was negatively associated with the incidence of bacillary dysentery (with RR: 0.57, 95% CI: 0.40-0.86). Therfore, this research suggests that floods exert a significant part in enhancing the risk of bacillary dysentery in Baise. Moreover, severe floods have a higher proportional contribution to the incidence of bacillary dysentery than moderate floods. In addition, short-term floods may contribute more to the incidence of bacillary dysentery than a long-term flood. The findings from this research will provide more evidence to reduce health risks related to floods.

The Effects of Floods on the Incidence of Bacillary Dysentery in Baise (Guangxi Province, China) from 2004 to 2012

PubMed Central

Liu, Xuena; Liu, Zhidong; Zhang, Ying; Jiang, Baofa

2017-01-01

Research shows potential effects of floods on intestinal infections. Baise, a city in Guangxi Province (China) had experienced several floods between 2004 and 2012 due to heavy and constant precipitation. This study aimed to examine the relationship between floods and the incidence of bacillary dysentery in Baise. A mixed generalized additive model and Spearman correlation were applied to analyze the relationship between monthly incidence of bacillary dysentery and 14 flood events with two severity levels. Data collected from 2004 to 2010 were utilized to estimate the parameters, whereas data from 2011 to 2012 were used to validate the model. There were in total 9255 cases of bacillary dysentery included in our analyses. According to the mixed generalized additive model, the relative risks (RR) of moderate and severe floods on the incidence of bacillary dysentery were 1.40 (95% confidence interval (CI): 1.16–1.69) and 1.78 (95% CI: 1.61–1.97), respectively. The regression analysis also indicated that the flood duration was negatively associated with the incidence of bacillary dysentery (with RR: 0.57, 95% CI: 0.40–0.86). Therfore, this research suggests that floods exert a significant part in enhancing the risk of bacillary dysentery in Baise. Moreover, severe floods have a higher proportional contribution to the incidence of bacillary dysentery than moderate floods. In addition, short-term floods may contribute more to the incidence of bacillary dysentery than a long-term flood. The findings from this research will provide more evidence to reduce health risks related to floods. PMID:28208681

Hydrologic risk analysis in the Yangtze River basin through coupling Gaussian mixtures into copulas

NASA Astrophysics Data System (ADS)

Fan, Y. R.; Huang, W. W.; Huang, G. H.; Li, Y. P.; Huang, K.; Li, Z.

2016-02-01

In this study, a bivariate hydrologic risk framework is proposed through coupling Gaussian mixtures into copulas, leading to a coupled GMM-copula method. In the coupled GMM-Copula method, the marginal distributions of flood peak, volume and duration are quantified through Gaussian mixture models and the joint probability distributions of flood peak-volume, peak-duration and volume-duration are established through copulas. The bivariate hydrologic risk is then derived based on the joint return period of flood variable pairs. The proposed method is applied to the risk analysis for the Yichang station on the main stream of the Yangtze River, China. The results indicate that (i) the bivariate risk for flood peak-volume would keep constant for the flood volume less than 1.0 × 105 m3/s day, but present a significant decreasing trend for the flood volume larger than 1.7 × 105 m3/s day; and (ii) the bivariate risk for flood peak-duration would not change significantly for the flood duration less than 8 days, and then decrease significantly as duration value become larger. The probability density functions (pdfs) of the flood volume and duration conditional on flood peak can also be generated through the fitted copulas. The results indicate that the conditional pdfs of flood volume and duration follow bimodal distributions, with the occurrence frequency of the first vertex decreasing and the latter one increasing as the increase of flood peak. The obtained conclusions from the bivariate hydrologic analysis can provide decision support for flood control and mitigation.

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

NASA Astrophysics Data System (ADS)

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.

2010-2011 Queensland floods: using Haddon's Matrix to define and categorise public safety strategies.

PubMed

Zhong, Shuang; Clark, Michele; Hou, Xiang-Yu; Zang, Yu-Li; FitzGerald, Gerry

2013-08-01

The 2010-2011 Queensland floods resulted in the most deaths from a single flood event in Australia since 1916. This article analyses the information on these deaths for comparison with those from previous floods in modern Australia in an attempt to identify factors that have contributed to those deaths. Haddon's Matrix, originally designed for prevention of road trauma, offers a framework for understanding the interplay between contributing factors and helps facilitate a clearer understanding of the varied strategies required to ensure people's safety for particular flood types. Public reports and flood relevant literature were searched using key words 'flood', 'fatality', 'mortality', 'death', 'injury' and 'victim' through Google Scholar, PubMed, ProQuest and EBSCO. Data relating to reported deaths during the 2010-2011 Queensland floods, and relevant data of previous Australian flood fatality (1997-2009) were collected from these available sources. These sources were also used to identify contributing factors. There were 33 deaths directly attributed to the event, of which 54.5% were swept away in a flash flood on 10 January 2011. A further 15.1% of fatalities were caused by inappropriate behaviours. This is different to floods in modern Australia where over 90% of deaths are related to the choices made by individuals. There is no single reason why people drown in floods, but rather a complex interplay of factors. The present study and its integration of research findings and conceptual frameworks might assist governments and communities to develop policies and strategies to prevent flood injury and fatalities. © 2013 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

The index-flood and the GRADEX methods combination for flood frequency analysis.

NASA Astrophysics Data System (ADS)

Fuentes, Diana; Di Baldassarre, Giuliano; Quesada, Beatriz; Xu, Chong-Yu; Halldin, Sven; Beven, Keith

2017-04-01

Flood frequency analysis is used in many applications, including flood risk management, design of hydraulic structures, and urban planning. However, such analysis requires of long series of observed discharge data which are often not available in many basins around the world. In this study, we tested the usefulness of combining regional discharge and local precipitation data to estimate the event flood volume frequency curve for 63 catchments in Mexico, Central America and the Caribbean. This was achieved by combining two existing flood frequency analysis methods, the regionalization index-flood approach with the GRADEX method. For up to 10-years return period, similar shape of the scaled flood frequency curve for catchments with similar flood behaviour was assumed from the index-flood approach. For return periods larger than 10-years the probability distribution of rainfall and discharge volumes were assumed to be asymptotically and exponential-type functions with the same scale parameter from the GRADEX method. Results showed that if the mean annual flood (MAF), used as index-flood, is known, the index-flood approach performed well for up to 10 years return periods, resulting in 25% mean relative error in prediction. For larger return periods the prediction capability decreased but could be improved by the use of the GRADEX method. As the MAF is unknown at ungauged and short-period measured basins, we tested predicting the MAF using catchments climate-physical characteristics, and discharge statistics, the latter when observations were available for only 8 years. Only the use of discharge statistics resulted in acceptable predictions.

Effects of changes along the risk chain on flood risk

NASA Astrophysics Data System (ADS)

Duha Metin, Ayse; Apel, Heiko; Viet Dung, Nguyen; Guse, Björn; Kreibich, Heidi; Schröter, Kai; Vorogushyn, Sergiy; Merz, Bruno

2017-04-01

Interactions of hydrological and socio-economic factors shape flood disaster risk. For this reason, assessment of flood risk ideally takes into account the whole flood risk chain from atmospheric processes, through the catchment and river system processes to the damage mechanisms in the affected areas. Since very different processes at various scales are interacting along the flood risk, the impact of the single components is rather unclear. However for flood risk management, it is required to know the controlling factor of flood damages. The present study, using the flood-prone Mulde catchment in Germany, discusses the sensitivity of flood risk to disturbances along the risk chain: How do disturbances propagate through the risk chain? How do different disturbances combine or conflict and affect flood risk? In this sensitivity analysis, the five components of the flood risk change are included. These are climate, catchment, river system, exposure and vulnerability. A model framework representing the complete risk chain is combined with observational data to understand how the sensitivities evolve along the risk chain by considering three plausible change scenarios for each of five components. The flood risk is calculated by using the Regional Flood Model (RFM) which is based on a continuous simulation approach, including rainfall-runoff, 1D river network, 2D hinterland inundation and damage estimation models. The sensitivity analysis covers more than 240 scenarios with different combinations of the five components. It is investigated how changes in different components affect risk indicators, such as the risk curve and expected annual damage (EAD). In conclusion, it seems that changes in exposure and vulnerability seem to outweigh changes in hazard.

Assessing surface water flood risk and management strategies under future climate change: Insights from an Agent-Based Model.

PubMed

Jenkins, K; Surminski, S; Hall, J; Crick, F

2017-10-01

Climate change and increasing urbanization are projected to result in an increase in surface water flooding and consequential damages in the future. In this paper, we present insights from a novel Agent Based Model (ABM), applied to a London case study of surface water flood risk, designed to assess the interplay between different adaptation options; how risk reduction could be achieved by homeowners and government; and the role of flood insurance and the new flood insurance pool, Flood Re, in the context of climate change. The analysis highlights that while combined investment in property-level flood protection and sustainable urban drainage systems reduce surface water flood risk, the benefits can be outweighed by continued development in high risk areas and the effects of climate change. In our simulations, Flood Re is beneficial in its function to provide affordable insurance, even under climate change. However, the scheme does face increasing financial pressure due to rising surface water flood damages. If the intended transition to risk-based pricing is to take place then a determined and coordinated strategy will be needed to manage flood risk, which utilises insurance incentives, limits new development, and supports resilience measures. Our modelling approach and findings are highly relevant for the ongoing regulatory and political approval process for Flood Re as well as for wider discussions on the potential of insurance schemes to incentivise flood risk management and climate adaptation in the UK and internationally. Copyright © 2017 Elsevier B.V. All rights reserved.

Floods of 1952 in California. Flood of January 1952 in the south San Francisco Bay region; Snowmelt flood of 1952 in Kern River, Tulare Lake, and San Joaquin River basins

USGS Publications Warehouse

Rantz, S.E.; Stafford, H.M.

1956-01-01

Two major floods occurred in California in 1952. The first was the flood of January 11-13 in the south San Francisco Bay region that resulted from heavy rains which began on the morning of January 11 and ended about noon January 13. This flood was notable for the magnitude of the peak discharges, although these discharges were reduced by the controlling effect of reservoirs for conservation and flood-control purposes. The flood damage was thereby reduced, and no lives were lost; damage, nevertheless, amounted to about $1.400.000. The second flood was due, not to the immediate runoff of heavy rain, but to the melting of one of the largest snow packs ever recorded in the Sierra Nevada range. In the spring and summer of 1952, flood runoff occurred on all the major streams draining the Sierra Nevada. In the northern half of the Central Valley basin?the Sacramento River basin?flood volumes and maximum daily discharges were not exceptional. and flood damage was not appreciable. However, in the southern half, which is formed by the Kern River, Tulare Lake, and San Joaquin River basins, new records for snowmelt runoff were established for some streams; but for below-normal temperatures and shorter, less warm hot spells, record flood discharges would have occurred on many others. In the three basins an area of 200,000 acres. largely cropland. was inundated, and damage was estimated at $11,800,000.

Climate-driven variability in the occurrence of major floods across North America and Europe

NASA Astrophysics Data System (ADS)

Hodgkins, Glenn A.; Whitfield, Paul H.; Burn, Donald H.; Hannaford, Jamie; Renard, Benjamin; Stahl, Kerstin; Fleig, Anne K.; Madsen, Henrik; Mediero, Luis; Korhonen, Johanna; Murphy, Conor; Wilson, Donna

2017-09-01

Concern over the potential impact of anthropogenic climate change on flooding has led to a proliferation of studies examining past flood trends. Many studies have analysed annual-maximum flow trends but few have quantified changes in major (25-100 year return period) floods, i.e. those that have the greatest societal impacts. Existing major-flood studies used a limited number of very large catchments affected to varying degrees by alterations such as reservoirs and urbanisation. In the current study, trends in major-flood occurrence from 1961 to 2010 and from 1931 to 2010 were assessed using a very large dataset (>1200 gauges) of diverse catchments from North America and Europe; only minimally altered catchments were used, to focus on climate-driven changes rather than changes due to catchment alterations. Trend testing of major floods was based on counting the number of exceedances of a given flood threshold within a group of gauges. Evidence for significant trends varied between groups of gauges that were defined by catchment size, location, climate, flood threshold and period of record, indicating that generalizations about flood trends across large domains or a diversity of catchment types are ungrounded. Overall, the number of significant trends in major-flood occurrence across North America and Europe was approximately the number expected due to chance alone. Changes over time in the occurrence of major floods were dominated by multidecadal variability rather than by long-term trends. There were more than three times as many significant relationships between major-flood occurrence and the Atlantic Multidecadal Oscillation than significant long-term trends.

Climate-driven variability in the occurrence of major floods across North America and Europe

USGS Publications Warehouse

Hodgkins, Glenn A.; Whitfield, Paul H.; Burn, Donald H.; Hannaford, Jamie; Renard, Benjamin; Stahl, Kerstin; Fleig, Anne K.; Madsen, Henrik; Mediero, Luis; Korhonen, Johanna; Murphy, Conor; Wilson, Donna

2017-01-01

Concern over the potential impact of anthropogenic climate change on flooding has led to a proliferation of studies examining past flood trends. Many studies have analysed annual-maximum flow trends but few have quantified changes in major (25–100 year return period) floods, i.e. those that have the greatest societal impacts. Existing major-flood studies used a limited number of very large catchments affected to varying degrees by alterations such as reservoirs and urbanisation. In the current study, trends in major-flood occurrence from 1961 to 2010 and from 1931 to 2010 were assessed using a very large dataset (>1200 gauges) of diverse catchments from North America and Europe; only minimally altered catchments were used, to focus on climate-driven changes rather than changes due to catchment alterations. Trend testing of major floods was based on counting the number of exceedances of a given flood threshold within a group of gauges. Evidence for significant trends varied between groups of gauges that were defined by catchment size, location, climate, flood threshold and period of record, indicating that generalizations about flood trends across large domains or a diversity of catchment types are ungrounded. Overall, the number of significant trends in major-flood occurrence across North America and Europe was approximately the number expected due to chance alone. Changes over time in the occurrence of major floods were dominated by multidecadal variability rather than by long-term trends. There were more than three times as many significant relationships between major-flood occurrence and the Atlantic Multidecadal Oscillation than significant long-term trends.

Some floods in the Rocky Mountain region: Chapter G in Contributions to the hydrology of the United States, 1923-1924

USGS Publications Warehouse

Follansbee, Robert; Hodges, Paul V.

1925-01-01

In 1923 severe floods occurred on the larger streams in Wyoming and a number of cloudburst floods on small streams in Wyoming and especially in Colorado. An investigation of the principal floods in each State was made, and the results are given in this paper, together with descriptions of two Colorado floods of 1922. In addition a study was made of all cloudburst floods to determine the areas chiefly subject to them.

Floods in the English River basin, Iowa

USGS Publications Warehouse

Heinitz, A.J.; Riddle, D.E.

1981-01-01

Information describing floods is essential for proper planning, design, and operation of bridges and other structures on or over streams and their flood plains. This report provides information on flood stages and discharges, flood magnitude and frequency, bench mark data, and flood profiles for the English River and some of its tributaries. It covers the English River, the North English River to near Guernsey, the south Eaglish River to Barnes City and the lower reaches of the Biddle English and Deep Rivers

Predictability of state-level flood damage in the conterminous United States: the role of hazard, exposure and vulnerability

DOE PAGES

Zhou, Qianqian; Leng, Guoyong; Feng, Leyang

2017-07-13

Understanding historical changes in flood damage and the underlying mechanisms is critical for predicting future changes for better adaptations. In this study, a detailed assessment of flood damage for 1950–1999 is conducted at the state level in the conterminous United States (CONUS). Geospatial datasets on possible influencing factors are then developed by synthesizing natural hazards, population, wealth, cropland and urban area to explore the relations with flood damage. A considerable increase in flood damage in CONUS is recorded for the study period which is well correlated with hazards. Comparably, runoff indexed hazards simulated by the Variable Infiltration Capacity (VIC) modelmore » can explain a larger portion of flood damage variations than precipitation in 84% of the states. Cropland is identified as an important factor contributing to increased flood damage in central US while urbanland exhibits positive and negative relations with total flood damage and damage per unit wealth in 20 and 16 states, respectively. Altogether, flood damage in 34 out of 48 investigated states can be predicted at the 90% confidence level. In extreme cases, ~76% of flood damage variations can be explained in some states, highlighting the potential of future flood damage prediction based on climate change and socioeconomic scenarios.« less

Plants are less negatively affected by flooding when growing in species-rich plant communities.

PubMed

Wright, Alexandra J; de Kroon, Hans; Visser, Eric J W; Buchmann, Tina; Ebeling, Anne; Eisenhauer, Nico; Fischer, Christine; Hildebrandt, Anke; Ravenek, Janneke; Roscher, Christiane; Weigelt, Alexandra; Weisser, Wolfgang; Voesenek, Laurentius A C J; Mommer, Liesje

2017-01-01

Flooding is expected to increase in frequency and severity in the future. The ecological consequences of flooding are the combined result of species-specific plant traits and ecological context. However, the majority of past flooding research has focused on individual model species under highly controlled conditions. An early summer flooding event in a grassland biodiversity experiment in Jena, Germany, provided the opportunity to assess flooding responses of 60 grassland species in monocultures and 16-species mixtures. We examined plant biomass, species-specific traits (plant height, specific leaf area (SLA), root aerenchyma, starch content) and soil porosity. We found that, on average, plant species were less negatively affected by the flood when grown in higher-diversity plots in July 2013. By September 2013, grasses were unaffected by the flood regardless of plant diversity, and legumes were severely negatively affected regardless of plant diversity. Plants with greater SLA and more root aerenchyma performed better in September. Soil porosity was higher in higher-diversity plots and had a positive effect on plant performance. As floods become more frequent and severe in the future, growing flood-sensitive plants in higher-diversity communities and in soil with greater soil aeration may attenuate the most negative effects of flooding. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Strong shift in the diazotrophic endophytic bacterial community inhabiting rice (Oryza sativa) plants after flooding.

PubMed

Ferrando, Lucía; Fernández Scavino, Ana

2015-09-01

Flooding impacts soil microbial communities, but its effect on endophytic communities has rarely been explored. This work addresses the effect of flooding on the abundance and diversity of endophytic diazotrophic communities on rice plants established in a greenhouse experiment. The nifH gene was significantly more abundant in roots after flooding, whereas the nifH gene copy numbers in leaves were unaffected and remained low. The PCA (principal component analysis) of T-RFLP (terminal restriction fragment length polymorphism) profiles indicated that root communities of replicate plots were more similar and diverse after flooding than before flooding. The nifH libraries obtained by cloning and 454 pyrosequencing consistently showed a remarkable shift in the diazotrophic community composition after flooding. Gammaproteobacteria (66-98%), mainly of the genus Stenotrophomonas, prevailed in roots before flooding, whereas Betaproteobacteria was the dominant class (26-34%) after flooding. A wide variety of aerotolerant and anaerobic diazotrophic bacteria (e.g. Dechloromonas, Rhodopseudomonas, Desulfovibrio, Geobacter, Chlorobium, Spirochaeta, Selenomonas and Dehalobacter) with diverse metabolic traits were retrieved from flooded rice roots. These findings suggest that endophytic communities could be significantly impacted by changes in plant-soil conditions derived from flooding during rice cropping. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Flood hazards in the Seattle-Tacoma urban complex and adjacent areas, Washington

USGS Publications Warehouse

Foxworthy, B.L.; Nassar, E.G.

1975-01-01

Floods are natural hazards that have complicated man's land-use planning for as long as we have had a history. Although flood hzards are a continuing danger, the year-to-year threat cannot be accurately predicted. Also, on any one stream, the time since the last destructive flood might be so long that most people now living near the stream have not experienced such a flood. Because of the unpredictability and common infrequency of disastrous flooding, or out of ignorance about the danger, or perhaps because of an urge to gamble, man tends to focus his attention on only the advantages of the flood-prone areas, rather than the risk due to the occasional major flood. The purposes of this report are to: (1) briefly describe flood hazards in this region, including some that may be unique to the Puget Sound basin, (2) indicate the parts of the area for which flood-hazard data are available, and (3) list the main sources of hydrologic information that is useful for flood-hazard analysis in conjuction with long-range planning. This map-type report is one of a series being prepared by the U.S. Geological Survey to present basic environmental information and interpretations to assist land-use planning in the Puget Sound region.

Prediction of Flood Warning in Taiwan Using Nonlinear SVM with Simulated Annealing Algorithm

NASA Astrophysics Data System (ADS)

Lee, C.

2013-12-01

The issue of the floods is important in Taiwan. It is because the narrow and high topography of the island make lots of rivers steep in Taiwan. The tropical depression likes typhoon always causes rivers to flood. Prediction of river flow under the extreme rainfall circumstances is important for government to announce the warning of flood. Every time typhoon passed through Taiwan, there were always floods along some rivers. The warning is classified to three levels according to the warning water levels in Taiwan. The propose of this study is to predict the level of floods warning from the information of precipitation, rainfall duration and slope of riverbed. To classify the level of floods warning by the above-mentioned information and modeling the problems, a machine learning model, nonlinear Support vector machine (SVM), is formulated to classify the level of floods warning. In addition, simulated annealing (SA), a probabilistic heuristic algorithm, is used to determine the optimal parameter of the SVM model. A case study of flooding-trend rivers of different gradients in Taiwan is conducted. The contribution of this SVM model with simulated annealing is capable of making efficient announcement for flood warning and keeping the danger of flood from residents along the rivers.

Policy tenure under the U.S. National Flood Insurance Program (NFIP).

PubMed

Michel-Kerjan, Erwann; Lemoyne de Forges, Sabine; Kunreuther, Howard

2012-04-01

In the United States, insurance against flood hazard (inland flooding or storm surge from hurricanes) has been provided mainly through the National Flood Insurance Program (NFIP) since 1968. The NFIP covers $1.23 trillion of assets today. This article provides the first analysis of flood insurance tenure ever undertaken: that is, the number of years that people keep their flood insurance policy before letting it lapse. Our analysis of the entire portfolio of the NFIP over the period 2001-2009 reveals that the median tenure of new policies during that time is between two and four years; it is also relatively stable over time and levels of flood hazard. Prior flood experience can affect tenure: people who have experienced small flood claims tend to hold onto their insurance longer; people who have experienced large flood claims tend to let their insurance lapse sooner. To overcome the policy and governance challenges posed by homeowners' inadequate insurance coverage, we discuss policy recommendations that include for banks and government-sponsored enterprises (GSEs) strengthening their requirements and the introduction of multiyear flood insurance contracts attached to the property, both of which are likely to provide more coverage stability and encourage investments in risk-reduction measures. © 2011 Society for Risk Analysis.

Methods for estimating magnitude and frequency of floods in Montana based on data through 1983

USGS Publications Warehouse

Omang, R.J.; Parrett, Charles; Hull, J.A.

1986-01-01

Equations are presented for estimating flood magnitudes for ungaged sites in Montana based on data through 1983. The State was divided into eight regions based on hydrologic conditions, and separate multiple regression equations were developed for each region. These equations relate annual flood magnitudes and frequencies to basin characteristics and are applicable only to natural flow streams. In three of the regions, equations also were developed relating flood magnitudes and frequencies to basin characteristics and channel geometry measurements. The standard errors of estimate for an exceedance probability of 1% ranged from 39% to 87%. Techniques are described for estimating annual flood magnitude and flood frequency information at ungaged sites based on data from gaged sites on the same stream. Included are curves relating flood frequency information to drainage area for eight major streams in the State. Maximum known flood magnitudes in Montana are compared with estimated 1 %-chance flood magnitudes and with maximum known floods in the United States. Values of flood magnitudes for selected exceedance probabilities and values of significant basin characteristics and channel geometry measurements for all gaging stations used in the analysis are tabulated. Included are 375 stations in Montana and 28 nearby stations in Canada and adjoining States. (Author 's abstract)

Predictability of state-level flood damage in the conterminous United States: the role of hazard, exposure and vulnerability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Qianqian; Leng, Guoyong; Feng, Leyang

Understanding historical changes in flood damage and the underlying mechanisms is critical for predicting future changes for better adaptations. In this study, a detailed assessment of flood damage for 1950–1999 is conducted at the state level in the conterminous United States (CONUS). Geospatial datasets on possible influencing factors are then developed by synthesizing natural hazards, population, wealth, cropland and urban area to explore the relations with flood damage. A considerable increase in flood damage in CONUS is recorded for the study period which is well correlated with hazards. Comparably, runoff indexed hazards simulated by the Variable Infiltration Capacity (VIC) modelmore » can explain a larger portion of flood damage variations than precipitation in 84% of the states. Cropland is identified as an important factor contributing to increased flood damage in central US while urbanland exhibits positive and negative relations with total flood damage and damage per unit wealth in 20 and 16 states, respectively. Altogether, flood damage in 34 out of 48 investigated states can be predicted at the 90% confidence level. In extreme cases, ~76% of flood damage variations can be explained in some states, highlighting the potential of future flood damage prediction based on climate change and socioeconomic scenarios.« less

Flood boundaries and water-surface profile for the computed 100-year flood, Swift Creek at Afton, Wyoming, 1986

USGS Publications Warehouse

Rankl, James G.; Wallace, Joe C.

1989-01-01

Flood flows on Swift Creek near Afton, Wyoming, were analyzed. Peak discharge with an average recurrence interval of 100 years was computed and used to determine the flood boundaries and water surface profile in the study reach. The study was done in cooperation with Lincoln County and the Town of Afton to determine the extent of flooding in the Town of Afton from a 100-year flood on Swift Creek. The reach of Swift Creek considered in the analysis extends upstream from the culvert at Allred County Road No. 12-135 to the US Geological Survey streamflow-gaging station located in the Bridger National Forest , a distance of 3.2 miles. Boundaries of the 100-year flood are delineated on a map using the computed elevation of the flood at each cross section, survey data, and a 1983 aerial photograph. The computed water surface elevation for the 100-year flood was plotted at each cross section, then the lateral extent of the flood was transferred to the flood map. Boundaries between cross sections were sketched using information taken from the aerial photograph. Areas that are inundated, but not part of the active flow, are designated on the cross sections. (Lantz-PTT)

Floods of May and June 2008 in Iowa

USGS Publications Warehouse

Buchmiller, Robert C.; Eash, David A.

2010-01-01

An unusually wet winter and spring of 2007 to 2008 resulted in extremely wet antecedent conditions throughout most of Iowa. Rainfall of 5 to 15 inches was observed in eastern Iowa during May 2008, and an additional 5 to 15 inches of rain was observed throughout most of Iowa in June. Because of the severity of the May and June 2008 flooding, the U.S. Geological Survey, in cooperation with other Federal, State, and local agencies, has summarized the meteorological and hydrological conditions leading to the flooding, compiled flood-peak stages and discharges, and estimated revised flood probabilities for 62 selected streamgages. Record peak discharges or flood probabilities of 1 percent or smaller (100-year flooding or greater) occurred at more than 60 streamgage locations, particularly in eastern Iowa. Cedar Rapids, Decorah, Des Moines, Iowa City, Mason City, and Waterloo were among the larger urban areas affected by this flooding. High water and flooding in small, headwater streams in north-central and eastern Iowa, particularly in June, combined and accumulated in large, mainstem rivers and resulted in flooding of historic proportions in the Cedar and Iowa Rivers. Previous flood-peak discharges at many locations were exceeded by substantial amounts, in some cases nearly doubling the previous record peak discharge at locations where more than 100 years of streamflow record are available.

Examining the effects of urban agglomeration polders on flood events in Qinhuai River basin, China with HEC-HMS model.

PubMed

Gao, Yuqin; Yuan, Yu; Wang, Huaizhi; Schmidt, Arthur R; Wang, Kexuan; Ye, Liu

2017-05-01

The urban agglomeration polders type of flood control pattern is a general flood control pattern in the eastern plain area and some of the secondary river basins in China. A HEC-HMS model of Qinhuai River basin based on the flood control pattern was established for simulating basin runoff, examining the impact of urban agglomeration polders on flood events, and estimating the effects of urbanization on hydrological processes of the urban agglomeration polders in Qinhuai River basin. The results indicate that the urban agglomeration polders could increase the peak flow and flood volume. The smaller the scale of the flood, the more significant the influence of the polder was to the flood volume. The distribution of the city circle polder has no obvious impact on the flood volume, but has effect on the peak flow. The closer the polder is to basin output, the smaller the influence it has on peak flows. As the level of urbanization gradually improving of city circle polder, flood volumes and peak flows gradually increase compared to those with the current level of urbanization (the impervious rate was 20%). The potential change in flood volume and peak flow with increasing impervious rate shows a linear relationship.

Incidence of and risk factors for musculoskeletal symptoms in the neck and low-back during severe flooding in Bangkok in 2011.

PubMed

Sihawong, Rattaporn; Janwantanakul, Prawit; Pensri, Praneet

2012-07-01

To examine whether the incidences of neck and low-back symptoms were elevated during the severe floods that occurred in Bangkok, Thailand in 2011, and to explore flood-related risk factors for neck and low-back symptoms. Prospective cohort design. Severe flooding occurred in Bangkok and surrounding neighbourhoods between October and December, 2011. After the flood had subsided (January 2012), 377 healthy office workers, who were already taking part in a study on musculoskeletal symptoms, were asked about their contact with floodwater. Data were gathered from subjects, who had reported no neck and low-back symptoms at the end of September 2011 and who were affected by the flood. Two regression models for the outcomes of 3-month incidence of neck and low-back symptoms, respectively, were performed. Eighty-two percent of the subjects were affected by the flood. No flood-related factor was found to associate significantly with either neck or low-back symptoms. However, neck symptoms may be associated with commuting frequently through flooded areas, and low-back symptoms may be associated with the subjects' homes or workplaces being flooded. These findings indicate that more attention needs to be paid to the problem of musculoskeletal symptoms during flooding in urban areas, and that preventive measures are required.

The Effect of Seasonal Floods on Health: Analysis of Six Years of National Health Data and Flood Maps

PubMed Central

Saulnier, Dell D.; Hanson, Claudia; Ir, Por; Mölsted Alvesson, Helle; von Schreeb, Johan

2018-01-01

There is limited knowledge on the effect of seasonal flooding on health over time. We quantified the short- and long-term effects of floods on selected health indicators at public healthcare facilities in 11 districts in Cambodia, a flood-prone setting. Counts of inpatient discharge diagnoses and outpatient consultations for diarrhea, acute respiratory infections, skin infections, injuries, noncommunicable diseases and vector-borne diseases were retrieved from public healthcare facilities for each month between January 2008 and December 2013. Flood water was mapped by month, in square kilometers, from satellite data. Poisson regression models with three lag months were constructed for the health problems in each district, controlled for seasonality and long-term trends. During times of flooding and three months after, there were small to moderate increases in visits to healthcare facilities for skin infections, acute respiratory infections, and diarrhea, while no association was seen at one to two months. The associations were small to moderate, and a few of our results were significant. We observed increases in care seeking for diarrhea, skin infections, and acute respiratory infections following floods, but the associations are uncertain. Additional research on previous exposure to flooding, using community- and facility-based data, would help identify expected health risks after floods in flood-prone settings. PMID:29614051

Towards River Rehabilitation as AN Integrated Approach to Flood Management in Asian Cities

NASA Astrophysics Data System (ADS)

Higgitt, David L.

Flood management in Asian cities has conventionally been approached through structural intervention where floods are regarded as a threat requiring control through engineering infrastructure. Such a command and control paradigm represents a marked transition from the way that monsoon flood regimes have been traditionally perceived across Asia. Rapid urbanization and climate change has imposed increasingly difficult flood management challenges as an extension of impermeable surfaces generates rapid runoff and flash flooding, while cities expand into flood-prone areas. Property and communities are placed at enhanced risk. Urbanization reallocates risk as channel and floodplain modification influences flood regimes, while demands for flood protection at certain locations can redistribute risk to other areas. An increasing concern about flood hazard across Asian cities questions whether conventional solutions reliant on structural intervention are sustainable. Such questioning is mirrored by an alternative paradigm of rehabilitation in integrated river basin management — a recognition that restoring and sustaining functional river ecosystems with high biodiversity is one of the greatest challenges facing society. Rehabilitation initiatives demand a new approach to river basin management which encourage interdisciplinary activity, particularly between engineers, hydrologists, geomorphologists and ecologists. The paper sets out some preliminary ideas from a research project investigating the potential for river rehabilitation as a central tenet of flood management, with a particular focus on Asian cities.

Statewide Floods in Pennsylvania, January 1996

USGS Publications Warehouse

Thompson, R.E.

1996-01-01

Rivers and streams throughout Pennsylvania (fig. 1) experienced major flooding during January 1996. Flood stages (water-surface heights) and discharges (flows) in many of the Commonwealth's waterways were measured by the U.S. Geological Survey (USGS) and approached or exceeded record levels established during previous floods. Setting the stage for the flooding was an unusually cold beginning to the winter of 1995-96, which resulted in the early formation of ice in streams statewide. The anomaly of early ice was followed by a sequence of unusual meteorological events in January 1996, which, in many areas, resulted in the most widespread and severe flooding since that produced by tropical storm Agnes in June 1972. Locally, the flooding was the worst since August 1955 and, in some areas, since March 1936. In approximately 50 localities throughout Pennsylvania, flood effects were magnified when ice jams caused temporary damming of stream channels, resulting in the rapid rise of water levels and the subsequent overflow of water and ice onto flood plains. During the floods, the USGS collected stream-stage information on a near real- 42°-GffEAWa/CESJ DRWNAG. time basis at 189 streamflow-gaging stations across the Commonwealth. This information was used by various Federal, State, and local agencies to prepare flood forecasts and develop plans for emergency response.

Flood Disaster Risk Assessment of Rural Housings — A Case Study of Kouqian Town in China

PubMed Central

Zhang, Qi; Zhang, Jiquan; Jiang, Liupeng; Liu, Xingpeng; Tong, Zhijun

2014-01-01

Floods are a devastating kind of natural disaster. About half of the population in China lives in rural areas. Therefore, it is necessary to assess the flood disaster risk of rural housings. The results are valuable for guiding the rescue and relief goods layout. In this study, we take the severe flood disaster that happened at Kouqian Town in Jilin, China in 2010 as an example to build an risk assessment system for flood disaster on rural housings. Based on the theory of natural disaster risk formation and “3S” technology (remote sensing, geography information systems and global positioning systems), taking the rural housing as the bearing body, we assess the flood disaster risk from three aspects: hazard, exposure and vulnerability. The hazard presented as the flood submerging range and depth. The exposure presented as the values of the housing and the property in it. The vulnerability presented as the relationship between the losses caused by flood and flood depth. We validate the model by the field survey after the flood disaster. The risk assessment results highly coincide with the field survey losses. This model can be used to assess the risk of other flood events in this area. PMID:24705363

Large floods and climatic change during the Holocene on the Ara River, Central Japan

NASA Astrophysics Data System (ADS)

Grossman, Michael J.

2001-07-01

A reconstruction of part of the Holocene large flood record for the Ara River in central Japan is presented. Maximum intermediate gravel-size dimensions of terrace and modern floodplain gravels were measured along an 18-km reach of the river and were used in tractive force equations to estimate minimum competent flood depths. Results suggest that the magnitudes of large floods on the Ara River have varied in a non-random fashion since the end of the last glacial period. Large floods with greater magnitudes occurred during the warming period of the post-glacial and the warmer early to middle Holocene (to ˜5500 years BP). A shift in the magnitudes of large floods occurred ˜5500-5000 years BP. From this time, during the cooler middle to late Holocene, large floods generally had lower magnitudes. In the modern period, large flood magnitudes are the largest in the data set. As typhoons are the main cause of large floods on the Ara River in the modern record, the variation in large flood magnitudes suggests that the incidence of typhoon visits to the central Japan changed as the climate changed during the Holocene. Further, significant dates in the large flood record on the Ara River correspond to significant dates in Europe and the USA.

Characterization of proteins in soybean roots under flooding and drought stresses.

PubMed

Oh, MyeongWon; Komatsu, Setsuko

2015-01-30

Flooding and drought affect soybean growth because soybean is a stress-sensitive crop. In 2-day-old plants exposed to 2-day flooding or drought, the fresh weight of roots was markedly suppressed, although the root morphology clearly differed between two conditions. To understand the response mechanisms of soybean to flooding and drought stresses, a gel-free proteomic technique was used. A total of 97 and 48 proteins were significantly changed in response to flooding and drought stresses, respectively. Proteins involved in protein synthesis were decreased by flooding stress and increased by drought. Glycolysis-related proteins were increased in roots by both flooding and drought stresses. Fermentation, stress, and cell wall-related proteins were increased in response to flooding stress, whereas cell organization and redox-related proteins were increased under drought stress. Among the identified proteins, three S-adenosylmethionine synthetases were commonly decreased and increased in response to flooding and drought stresses, respectively. The mRNA expression levels of S-adenosylmethionine synthetase genes displayed a similar tendency to the changes in protein abundance. These results suggest that S-adenosylmethionine synthetase is involved in the regulation of stress response because it was changed in response to flooding and drought stresses. This study reported on the response mechanisms of soybean to flooding and drought stresses using the gel-free proteomic technique. Proteins involved in protein synthesis were decreased by flooding stress and increased by drought. Glycolysis-related proteins were increased in roots by both flooding and drought stresses. Fermentation, stress, and cell wall-related proteins were increased in response to flooding stress, whereas cell organization and redox-related proteins were increased under drought stress. Among the identified proteins, three S-adenosylmethionine synthetases were commonly decreased and increased in response to flooding and drought stresses, respectively. The mRNA expression levels of S-adenosylmethionine synthetase genes displayed a similar tendency to the changes in protein abundance. These results suggest that S-adenosylmethionine synthetase is involved in the regulation of stress response because it was changed in response to flooding and drought stresses. Copyright © 2014 Elsevier B.V. All rights reserved.

General characteristics of causes of urban flood damage and flood forecasting/warning system in Seoul, Korea Young-Il Moon1, 2, Jong-Suk Kim1, 2 1 Department of Civil Engineering, University of Seoul, Seoul 130-743, South Korea 2 Urban Flood Research Inst

NASA Astrophysics Data System (ADS)

Moon, Young-Il; Kim, Jong-Suk

2015-04-01

Due to rapid urbanization and climate change, the frequency of concentrated heavy rainfall has increased, causing urban floods that result in casualties and property damage. As a consequence of natural disasters that occur annually, the cost of damage in Korea is estimated to be over two billion US dollars per year. As interest in natural disasters increase, demands for a safe national territory and efficient emergency plans are on the rise. In addition to this, as a part of the measures to cope with the increase of inland flood damage, it is necessary to build a systematic city flood prevention system that uses technology to quantify flood risk as well as flood forecast based on both rivers and inland water bodies. Despite the investment and efforts to prevent landside flood damage, research and studies of landside-river combined hydro-system is at its initial stage in Korea. Therefore, the purpose of this research introduces the causes of flood damage in Seoul and shows a flood forecasting and warning system in urban streams of Seoul. This urban flood forecasting and warning system conducts prediction on flash rain or short-term rainfall by using radar and satellite information and performs prompt and accurate prediction on the inland flooded area and also supports synthetic decision-making for prevention through real-time monitoring. Although we cannot prevent damage from typhoons or localized heavy rain, we can minimize that damage with accurate and timely forecast and a prevention system. To this end, we developed a flood forecasting and warning system, so in case of an emergency there is enough time for evacuation and disaster control. Keywords: urban flooding, flood risk, inland-river system, Korea Acknowledgments This research was supported by a grant (13AWMP-B066744-01) from Advanced Water Management Research Program (AWMP) funded by Ministry of Land, Infrastructure and Transport of Korean government.

Potential of high resolution satellite imagery, remote weather data and 1D hydraulic modeling to evaluate flood areas in Gonaives, Haiti

NASA Astrophysics Data System (ADS)

Bozza, Andrea; Durand, Arnaud; Allenbach, Bernard; Confortola, Gabriele; Bocchiola, Daniele

2013-04-01

We present a feasibility study to explore potential of high-resolution imagery, coupled with hydraulic flood modeling to predict flooding risks, applied to the case study of Gonaives basins (585 km²), Haiti. We propose a methodology working at different scales, providing accurate results and a faster intervention during extreme flood events. The 'Hispaniola' island, in the Caribbean tropical zone, is often affected by extreme floods events. Floods are caused by tropical springs and hurricanes, and may lead to several damages, including cholera epidemics, as recently occurred, in the wake of the earthquake upon January 12th 2010 (magnitude 7.0). Floods studies based upon hydrological and hydraulic modeling are hampered by almost complete lack of ground data. Thenceforth, and given the noticeable cost involved in the organization of field measurement campaigns, the need for exploitation of remote sensing images data. HEC-RAS 1D modeling is carried out under different scenarios of available Digital Elevation Models. The DEMs are generated using optical remote sensing satellite (WorldView-1) and SRTM, combined with information from an open source database (Open Street Map). We study two recent flood episodes, where flood maps from remote sensing were available. Flood extent and land use have been assessed by way of data from SPOT-5 satellite, after hurricane Jeanne in 2004 and hurricane Hanna in 2008. A semi-distributed, DEM based hydrological model is used to simulate flood flows during the hurricanes. Precipitation input is taken from daily rainfall data derived from TRMM satellite, plus proper downscaling. The hydraulic model is calibrated using floodplain friction as tuning parameters against the observed flooded area. We compare different scenarios of flood simulation, and the predictive power of model calibration. The method provide acceptable results in depicting flooded areas, especially considering the tremendous lack of ground data, and show the potential of remote sensing information in prediction of flood events in this area, for the purpose of risk assessment and land use planning, and possibly for flood forecast during extreme events.

Can global hydrological models reproduce large scale river flood regimes?

NASA Astrophysics Data System (ADS)

Eisner, Stephanie; Flörke, Martina

2013-04-01

River flooding remains one of the most severe natural hazards. On the one hand, major flood events pose a serious threat to human well-being, causing deaths and considerable economic damage. On the other hand, the periodic occurrence of flood pulses is crucial to maintain the functioning of riverine floodplains and wetlands, and to preserve the ecosystem services the latter provide. In many regions, river floods reveal a distinct seasonality, i.e. they occur at a particular time during the year. This seasonality is related to regionally dominant flood generating processes which can be expressed in river flood types. While in data-rich regions (esp. Europe and North America) the analysis of flood regimes can be based on observed river discharge time series, this data is sparse or lacking in many other regions of the world. This gap of knowledge can be filled by global modeling approaches. However, to date most global modeling studies have focused on mean annual or monthly water availability and their change over time while simulating discharge extremes, both floods and droughts, still remains a challenge for large scale hydrological models. This study will explore the ability of the global hydrological model WaterGAP3 to simulate the large scale patterns of river flood regimes, represented by seasonal pattern and the dominant flood type. WaterGAP3 simulates the global terrestrial water balance on a 5 arc minute spatial grid (excluding Greenland and Antarctica) at a daily time step. The model accounts for human interference on river flow, i.e. water abstraction for various purposes, e.g. irrigation, and flow regulation by large dams and reservoirs. Our analysis will provide insight in the general ability of global hydrological models to reproduce river flood regimes and thus will promote the creation of a global map of river flood regimes to provide a spatially inclusive and comprehensive picture. Understanding present-day flood regimes can support both flood risk analysis and the assessment of potential regional impacts of climate change on river flooding.

New developments at the Flood Forecasting Centre: operational flood risk assessment and guidance

NASA Astrophysics Data System (ADS)

Pilling, Charlie

2017-04-01

The Flood Forecasting Centre (FFC) is a partnership between the UK Met Office, the Environment Agency and Natural Resources Wales. The FFC was established in 2009 to provide an overview of flood risk across England and Wales and to provide flood guidance services primarily for the emergency response community. The FFC provides forecasts for all natural sources of flooding, these being fluvial, surface water, coastal and groundwater. This involves an assessment of possible hydrometeorological events and their impacts over the next five days. During times of heightened flood risk, the close communication between the FFC, the Environment Agency and Natural Resources Wales allows mobilization and deployment of staff and flood defences. Following a number of severe flood events during winters 2013-14 and 2015-16, coupled with a drive from the changing landscape in national incident response, there is a desire to identify flood events at even longer lead time. This earlier assessment and mobilization is becoming increasingly important and high profile within Government. For example, following the exceptional flooding across the north of England in December 2015 the Environment Agency have invested in 40 km of temporary barriers that will be moved around the country to help mitigate against the impacts of large flood events. Efficient and effective use of these barriers depends on identifying the broad regions at risk well in advance of the flood, as well as scaling the magnitude and duration of large events. Partly in response to this, the FFC now produce a flood risk assessment for a month ahead. In addition, since January 2017, the 'new generation' daily flood guidance statement includes an assessment of flood risk for the 6 to 10 day period. Examples of both these new products will be introduced, as will some of the new developments in science and technical capability that underpin these assessments. Examples include improvements to fluvial forecasting from 'fluvial decider', and downscaled hydrometeorological data that generates probabilistic river flows at 6 days lead time using the Delft-FEWS / Grid-to-Grid modelling system. Advances in coastal forecasting from surge and wave ensembles and also the longer range 'coastal decider' approach will also be presented.

Floods on White Rock Creek above White Rock Lake at Dallas, Texas

USGS Publications Warehouse

Gilbert, Clarence R.

1963-01-01

The White Rock Creek watershed within the city limits of Dallas , Texas, presents problems not unique in the rapid residential and industrial development encountered by many cities throughout the United States. The advantages of full development of the existing area within a city before expanding city boundaries, are related to both economics and civic pride. The expansion of city boundaries usually results in higher per capital costs for the operation of city governments. Certainly no responsible city official would oppose reasonable development of watersheds and flood plains and thus sacrifice an increase in tax revenue. Within the words "reasonable development" lies the problem faced by these officials. They are aware that the natural function of a stream channel, and its associated flood plain is to carry away excess water in time of flood. They are also aware that failure to recognize this has often led to haphazard development on flood plains with a consequent increase in flood damages. In the absence of factual data defining the risk involved in occupying flood plains, stringent corrective and preventative measures must be taken to regulate man's activities on flood plains to a point beyond normal precaution. Flood-flow characteristics in the reach of White Rock Creek that lies between the northern city boundary of Dallas and Northwest Highway (Loop 12) at the upper end of White Rock Lake, are presented in this report. Hydrologic data shown include history and magnitude of floods, flood profiles, outlines of areas inundated by three floods, and estimates of mean velocities of flow at selected points. Approximate areas inundated by floods of April 1942 and July 1962 along White Rock Creek and by the flood of October 1962 along Cottonwood Creek, Floyd Branch, and Jackson Branch, are delineated on maps. Greater floods have undoubtedly occurred in the past but no attempt is made to show their probable overflow limits because basic data on such floods could not be obtained. Depths of inundation can be estimated from the information shown. Elevations shown are in feet above mean sea level, datum of 1929. The data and computations supporting the results given herein are in the files of the Geological Survey in Austin, Texas.

An integrated approach to flood hazard assessment on alluvial fans using numerical modeling, field mapping, and remote sensing

USGS Publications Warehouse

Pelletier, J.D.; Mayer, L.; Pearthree, P.A.; House, P.K.; Demsey, K.A.; Klawon, J.K.; Vincent, K.R.

2005-01-01

Millions of people in the western United States live near the dynamic, distributary channel networks of alluvial fans where flood behavior is complex and poorly constrained. Here we test a new comprehensive approach to alluvial-fan flood hazard assessment that uses four complementary methods: two-dimensional raster-based hydraulic modeling, satellite-image change detection, fieldbased mapping of recent flood inundation, and surficial geologic mapping. Each of these methods provides spatial detail lacking in the standard method and each provides critical information for a comprehensive assessment. Our numerical model simultaneously solves the continuity equation and Manning's equation (Chow, 1959) using an implicit numerical method. It provides a robust numerical tool for predicting flood flows using the large, high-resolution Digital Elevation Models (DEMs) necessary to resolve the numerous small channels on the typical alluvial fan. Inundation extents and flow depths of historic floods can be reconstructed with the numerical model and validated against field- and satellite-based flood maps. A probabilistic flood hazard map can also be constructed by modeling multiple flood events with a range of specified discharges. This map can be used in conjunction with a surficial geologic map to further refine floodplain delineation on fans. To test the accuracy of the numerical model, we compared model predictions of flood inundation and flow depths against field- and satellite-based flood maps for two recent extreme events on the southern Tortolita and Harquahala piedmonts in Arizona. Model predictions match the field- and satellite-based maps closely. Probabilistic flood hazard maps based on the 10 yr, 100 yr, and maximum floods were also constructed for the study areas using stream gage records and paleoflood deposits. The resulting maps predict spatially complex flood hazards that strongly reflect small-scale topography and are consistent with surficial geology. In contrast, FEMA Flood Insurance Rate Maps (FIRMs) based on the FAN model predict uniformly high flood risk across the study areas without regard for small-scale topography and surficial geology. ?? 2005 Geological Society of America.

Assessment of channel changes, model of historical floods, and effects of backwater on flood stage, and flood mitigation alternatives for the Wichita River at Wichita Falls, Texas

USGS Publications Warehouse

Winters, Karl E.; Baldys, Stanley

2011-01-01

In cooperation with the City of Wichita Falls, the U.S. Geological Survey assessed channel changes on the Wichita River at Wichita Falls, Texas, and modeled historical floods to investigate possible causes and potential mitigation alternatives to higher flood stages in recent (2007 and 2008) floods. Extreme flooding occurred on the Wichita River on June 30, 2007, inundating 167 homes in Wichita Falls. Although a record flood stage was reached in June 2007, the peak discharge was much less than some historical floods at Wichita Falls. Streamflow and stage data from two gages on the Wichita River and one on Holliday Creek were used to assess the interaction of the two streams. Changes in the Wichita River channel were evaluated using historical aerial and ground photography, comparison of recent and historical cross sections, and comparison of channel roughness coefficients with those from earlier studies. The floods of 2007 and 2008 were modeled using a one-dimensional step-backwater model. Calibrated channel roughness was larger for the 2007 flood compared to the 2008 flood, and the 2007 flood peaked about 4 feet higher than the 2008 flood. Calibration of the 1941 flood yielded a channel roughness coefficient (Manning's n) of 0.030, which represents a fairly clean natural channel. The step-backwater model was also used to evaluate the following potential mitigation alternatives: (1) increasing the capacity of the bypass channel near River Road in Wichita Falls, Texas; (2) removal of obstructions near the Scott Avenue and Martin Luther King Junior Boulevard bridges in Wichita Falls, Texas; (3) widening of aggraded channel banks in the reach between Martin Luther King Junior Boulevard and River Road; and (4) reducing channel bank and overbank roughness. Reductions in water-surface elevations ranged from 0.1 foot to as much as 3.0 feet for the different mitigation alternatives. The effects of implementing a combination of different flood-mitigation alternatives were not investigated.