Catastrophic Flood Events Research Articles

Integration of multi-archive datasets for the development of a four-dimensional paleoflood model of alpine catchments

Both natural and documentary evidence of severe and catastrophic floods are of tremendous value for completing multidimensional flood calendars, as well as for mapping the most extreme riverine flooding phenomena in a river basin, over centennial and millennial time scales. Here, the integration of multi-archive flood series from the Hasli-Aare, Lütschine, Kander, Simme, Lombach, and Eistlenbach catchments in the Bernese Alps constitutes a unique approach to the reconstruction of flooding events over the last six centuries and to the development of a temporal-spatial model of past flood behavior. Different types of flood archive, be they of natural or anthropogenic origin, record different processes and legacies of these physical phenomena. In this study, paleoflood records obtained from floodplains (four flood series) and lake sediments (four series), together with documentary data (six series), were analyzed and compared with instrumental measurements (four series) and the profiles of lichenometric-dated flood heights (four series) to i) determine common flood pulses, ii) identify events that are out-of-phase, iii) investigate the sensitivity of the different natural archives to flood drivers and forcing, iv) locate past flooding in an alpine region of 2117 km2, and v) simulate atmospheric modes of climate variability during flood-rich periods from 1400 to 2005 CE. Asynchronous flood response across the sites is attributed to differences in their local hydrologic regimes, influenced by (i) their physiographic parameters, including size, altitude, storage capacity and connectivity of basins, and (ii) their climate parameters, including type, spatial distribution, duration, and intensity of precipitation. The most accurate, continuous series, corresponding to the period from 1400 to 2005 CE, were integrated into a synthetic flood master curve that defines ten dominant flood pulses. Six of these correspond to cooler climate pulses (around 1480, 1570, 1760, 1830, 1850 and 1870 CE), three to intermediate temperatures (around 1410, 1650 and 1710 CE), while the most recent corresponds to the current pulse of Global Warming (2005 CE). Furthermore, five coincide with the positive mode of the Summer North Atlantic Oscillation, characterized by a strong blocking anticyclone between the Scandinavia Peninsula and Great Britain. For two of the most catastrophic flood events in the Bernese Alps (those of 1762 and 1831 CE), the location and magnitude of all the flood records compiled were plotted to provide an accurate mapping of the spatial pattern of flooding. This was then compared to the pattern of atmospheric variability. The comprehensive 4-D picture of paleofloods thus achieved should facilitate an in-depth understanding of the floods and flood forcing in mountain catchments.

Sub-seasonal Levee Deformation Observed Using Satellite Radar Interferometry to Enhance Flood Protection

Levees are critical in providing protection against catastrophic flood events, and thus require continuous monitoring. Current levee inspection methods rely on limited information obtained by visual inspection, resulting in infrequent, localized, mostly qualitative and subjective assessments. This hampers the timely detection of problematic locations and the assessment of levee safety in general. Satellite radar interferometry yields weekly observations of levee conditions with high precision which complement current inspection methods. Here we show that levees are susceptible to short-term swelling and shrinkage associated with meteorological conditions, and assess how deformations can be related to the geohydrological properties and the safety of the levee. Our findings allow to understand the sub-seasonal behaviour of the levee in greater detail and to predict swelling and shrinkage due to variation of the loading conditions. This will improve the detection of anomalous levee responses which contributes to the development of reliable early warning methods using continuous deformation monitoring.

A Bayesian Approach to Prediction of Flood Risks

Flood is a temporary overflow of a dry area due to overflow of excess water, runoff surface waters or undermining of shoreline. In 2014, Malaysia grieved with the catastrophic flood event in Kuala Krai, Kelantan, which sacrificed human lives, public assets and a total of RM 2 billion loss. Due to uncertainties in flooding event, this research is set to compare three variations of Bayesian approaches in classifying the risk of flood into two classes; flood or no flood. The study involved data from Kuala Krai, which serves as the main observation point. The dataset contains six attributes, which are water level, rainfall daily, rainfall monthly, wind, humidity, and temperature. The classification experiment will be conducted using three variants of Bayesian approaches, which are Bayesian Networks (BN), Naïve Bayes (NB), and Tree Augmented Naive Bayes (TAN). The outcomes of this research will show the best algorithm performance in term of accuracy for three Bayesian-based learning prediction algorithms. In the future, this prediction system is hoped to assist related agencies in Malaysia to categorize land areas that face high risk of flood so preventive actions can be planned in place.

Applicability of satellite radar imaging to monitor the conditions of levees

Levees are critical systems in safeguarding an area against catastrophic flooding events with potential fatalities and economic losses. Current monitoring methods of levees highly rely on expert judgement, resulting in infrequent and subjective assessments of their status. Satellite radar imaging, in particular using interferometry (InSAR), holds a large potential to monitor the condition of levees with millimetre‐level precision, anywhere on the planet. However, for levee management, the usability of the technique requires significant radar expert knowledge. Here, we provide a comprehensive overview of the state of the art in using time‐series InSAR for systematic levee deformation monitoring. We explore its use to complement existing approaches for assessing levee deformation and failure investigations in a fast, systematic, and cost‐effective way. The applicability of imaging radar satellites is discussed, supported by case studies on levee monitoring in the Netherlands. We elaborate on the technical aspects with respect to levee monitoring using SAR technology, such as estimating deformation in different directions, satellite characteristics, precision, and reliability. We conclude that InSAR is becoming an operational deformation monitoring system, which allows for the detection, tracking, and analysis of irregularities on levee sections with increased efficiency and quality, thus contributing to improved risk management.

Cohabitants, Captives, or Trade

Abstract The Marseton #2 site is a Weaver ring midden in the Mississippi Valley of Mercer County, Illinois, that was buried by a catastrophic flood event a few centuries after the site had been abandoned. Analysis of the more than 740,000 ceramic items from the village provides insights as to Weaver interactions with other non-Weaver early Late Woodland groups of the region. While the presence of non-Weaver ceramics at the village might represent trade items, or vessels manufactured by potters peacefully or forcibly brought to the site, it is suggested that a non-Weaver household producing Levsen-like ceramics was coexisting at Marseton #2 alongside multiple Weaver households.

Exposing Practical, Psychological, and Pedagogical Shadow Sides of Experiential Learning

This article is based first-person experience with experiential learning (EL) practices in an undergraduate introductory management course. We consider how a challenging EL activity, based on volunteering during recovery from a catastrophic flood event, exposed three shadow sides of EL. These shadow sides of EL, which often remain hidden to educators, are practical, psychological, and pedagogical. We provide a characterization of each of these shadow sides and outline strategies for managing them. We also discuss the general applicability of our insights, including tentative theoretical extensions to Kolb’s EL theory. We conclude by considering the potential for the shadow sides of EL to emerge in circumstances that are less confronting and extreme than those encountered by our students.

Bottom-up citizen initiatives as emergent actors in flood risk management: Mapping roles, relations and limitations.

The recent shift to individualisation of flood risk calls for a stronger involvement of private actors. Bottom‐up citizen initiatives (BUIs) may bring together governmental bodies with people at risk. Drawing on a screening of existing BUIs in Europe, North America, and Australia and an in‐depth analysis of three study sites, this paper maps BUI activities to stages in the risk management cycle and discusses the institutional, relational and social proximity between BUIs and other stakeholders. Flood BUIs often take over roles that the authorities are not willing or able to fulfil. BUIs emerge out of frustration with current risk policies, after a catastrophic flood event, government‐initiated engagement projects or targeted funding opportunities. BUIs can take different forms, ranging from oppositional pressure groups, self‐help movements for disaster response and recovery, to initiatives formally installed by law. While self‐organised BUIs benefit from high proximity to their home communities, formalised BUIs are deeper embedded in existing institutional structures. In order to gain a stronger voice in the risk debate, BUIs need to expand from the local level to catchment areas and exchange expertise and resources in nationwide or cross‐border networks. However, BUIs may create parallel political structures that are not democratically legitimised.

Nighttime light data reveal how flood protection shapes human proximity to rivers.

To understand the spatiotemporal changes of flood risk, we need to determine the way in which humans adapt and respond to flood events. One adaptation option consists of resettling away from flood-prone areas to prevent or reduce future losses. We use satellite nighttime light data to discern the relationship between long-term changes in human proximity to rivers and the occurrence of catastrophic flood events. Moreover, we explore how these relationships are influenced by different levels of structural flood protection. We found that societies with low protection levels tend to resettle further away from the river after damaging flood events. Conversely, societies with high protection levels show no significant changes in human proximity to rivers. Instead, such societies continue to rely heavily on structural measures, reinforcing flood protection and quickly resettling in flood-prone areas after a flooding event. Our work reveals interesting aspects of human adaptation to flood risk and offers key insights for comparing different risk reduction strategies. In addition, this study provides a framework that can be used to further investigate human response to floods, which is relevant as urbanization of floodplains continues and puts more people and economic assets at risk.

Cohabitants, Captives, or Trade: The Early Late Woodland Non-Weaver Ceramic Assemblage at the Marseton #2 Weaver Village in Mercer County, Illinois

The Marseton #2 site is a Weaver ring midden in the Mississippi Valley of Mercer County, Illinois, that was buried by a catastrophic flood event a few centuries after the site had been abandoned. A...

Seismic signature of turbulence during the 2017 Oroville Dam spillway erosion crisis

Abstract. Knowing the location of large-scale turbulent eddies during catastrophic flooding events improves predictions of erosive scour. The erosion damage to the Oroville Dam flood control spillway in early 2017 is an example of the erosive power of turbulent flow. During this event, a defect in the simple concrete channel quickly eroded into a 47 m deep chasm. Erosion by turbulent flow is difficult to evaluate in real time, but near-channel seismic monitoring provides a tool to evaluate flow dynamics from a safe distance. Previous studies have had limited ability to identify source location or the type of surface wave (i.e., Love or Rayleigh wave) excited by different river processes. Here we use a single three-component seismometer method (frequency-dependent polarization analysis) to characterize the dominant seismic source location and seismic surface waves produced by the Oroville Dam flood control spillway, using the abrupt change in spillway geometry as a natural experiment. We find that the scaling exponent between seismic power and release discharge is greater following damage to the spillway, suggesting additional sources of turbulent energy dissipation excite more seismic energy. The mean azimuth in the 5–10 Hz frequency band was used to resolve the location of spillway damage. Observed polarization attributes deviate from those expected for a Rayleigh wave, though numerical modeling indicates these deviations may be explained by propagation up the uneven hillside topography. Our results suggest frequency-dependent polarization analysis is a promising approach for locating areas of increased flow turbulence. This method could be applied to other erosion problems near engineered structures as well as to understanding energy dissipation, erosion, and channel morphology development in natural rivers, particularly at high discharges.

Financing Flood Losses: A Discussion of the National Flood Insurance Program

The National Flood Insurance Program (NFIP), housed in the Federal Emergency Management Agency (FEMA), has been providing flood insurance to households and businesses for almost 50 years. To inform the policy discussion leading up to reauthorization, this paper analyzes five aspects of the NFIP: (1) risk modeling and risk communication; (2) the roles of the public and private sector; (3) take-up rates; (4) incentives for risk reduction; and (5) rate setting and the financing of catastrophic flood events. Suggestions for reform are discussed.

Financing Flood Losses: A Discussion of the National Flood Insurance Program

AbstractThe National Flood Insurance Program (NFIP), housed in the Federal Emergency Management Agency, has been providing flood insurance to households and businesses for almost 50 years. To inform the policy discussion leading up to reauthorization, this article analyzes five aspects of the NFIP: (1) risk modeling and risk communication, (2) the roles of the public and private sector, (3) take‐up rates, (4) incentives for risk reduction, and (5) rate setting and the financing of catastrophic flood events. Suggestions for reform are discussed.

Natural disasters written in historical woods: Floods, a thunderbolt fire and an earthquake

Abstract The present paper analyzes different types of natural disasters recorded in the woody elements from reconstruction or repair works in two World Heritage buildings (the Old Mint and the Cathedral) in Segovia (Central Spain). We employed architectural and historical documentation, along with archaeoseismological analysis techniques in order to frame the events and processes. We analyzed several woody elements from the wooden deck of the Old Mint, including beams, planks and support blocks; and for the Cathedral roof the structural elements analyzed were tiebeams, raised aisles, rafter braces, common rafters and roof battens, as well as many planks and soulaces. For the dating, we combined two methodological approaches based upon dendrochronological techniques (dendroarchaeology and dendrogeomorphology) in an integrated study of the tree-rings series obtained. Furthermore, four wood samples (one from the Old Mint and three from the Cathedral) were dated by means of radiocarbon techniques. The results enable us to detect and corroborate the dates of at least two catastrophic flood events that affected the Old Mint (1695 and 1733). Additionally, we establish the unknown effects to date upon the Cathedral roof of the fire caused by the thunderbolt in 1614 and by the Lisbon earthquake in 1755. From the point of view of cultural heritage, these data are of great interest for the history of the reconstruction of the Old Mint and of the Cathedral of Segovia.

Flash Flood Risk Assessment for Kyushu Island, Japan

Using advanced geospatial analysis technologies, flash flood risk is assessed for the island of Kyushu, Japan. In this study, the flash flood risk is redefined in terms of the flash flood potential index (FFPI) and the flash flood residential hazard (FFRH). The island experiences rainy weather, especially in the summer (June–August), when catastrophic flash flood events have historically occurred. Studies of the surface hydrological properties of the island are very rare and localized; hence, geospatial techniques are most appropriate for the assessment process. The Soil Conservation Service rainfall-runoff model was used to estimate hydrological responses on the island. Four factors were included in the flash flood assessment. A multi-criteria analysis was carried out to map the FFPI and FFRH from the evaluation factors. The results show that the highest flash flood risk occurs in the northern parts of the island, where the soil displays relatively low infiltration rates and relatively high curve numbers, despite the comparatively low precipitation rates that occur there. The results indicate that soil hydrological properties are the main driving forces of flash floods, especially in regions with low precipitation rates. The results of this research are consistent with previous in situ measurements of runoff made at several sites on the island. The results also show a strong geographic correlation with historical flash flood events on the island. This research validates the use of geospatial analysis for large geographic regions where in situ measurements cannot be taken due to time or cost constraints. The results of this study provide decision makers with the information needed to select a management strategy to address possible future flash flood events that considers safety and water harvesting.

Flow Characteristics of the Jamuna River: During the 1988 and 1998 Catastrophic Flood Events in Bangladesh

The 1988 and 1998 flood events hit Bangladesh which was more catastrophic in the present study area, Manikganj district. The Jamuna River has great locational influences to cause severe flood situations in the study area. Bangladesh Water Development Board (BWDB) provided the river stage data of the Jamuna for pivot table analysis and drawing hydrographs. The Jamuna River attained its highest peak 10.55 m in August and 10.58 m in September in 1988 flood at Arichaghat station which flowed 141 cm and 144 cm above its danger level (9.14 m). In 1998 flood event, the Jamuna rose up to 10.02 m in July, 10.35 m in August and 10.76 m in September that flowed respectively 88 cm, 121 cm and 162 cm above the danger level (9.14 m). As a whole, the Jamuna flowed above the danger level for 43 days in 1988 and 68 days in 1998 causing the devastating flood in the study area. A total of 2518 people lost their lives and damage to crops fisheries, livestock, was over 120 billion US dollar. About 125 km of local roads, national highways and several hundred bridges, over 250 educational institutions and 140 health structures were affected by the flood events.

A new Late Pennsylvanian floral assemblage from the Douro Basin, Portugal

The Douro Basin (lower Gzhelian/lower Stephanian C, Upper Pennsylvanian; NW Portugal) is one of the richest continental sedimentary basins in fossil floras of late Carboniferous age in Portugal. Recent field work carried out in the Douro Basin allowed to report a new fossil site, of potential Lagerstätte quality, found in the Montes da Costa (Ermesinde) region. This new fossil locality preserves exceptional palaeontological, stratigraphic, lithological, and tectonic structural features of great scientific interest. An exceptional record of sudden catastrophic flooding events represents one of the most remarkable geological records documented in this new locality. In the palaeontological context, the plant assemblage described comprises a well‐preserved and very diversified macroflora of early Gzhelian age, consisting of several fossil taxa belonging mainly to genera and species of Pteridopsida, Pteridospermopsida, and Sphenopsida. Its fossil records are essentially parautochthonous deposits, but several Calamites trunks preserved in autochthonous position were documented. Within the studied plant assemblage, a new species of arborescent marattialean fern, Acitheca murphyi sp. nov., is described, and several new floral occurrences are first reported in the Portuguese Carboniferous. Here, we analyse the palaeoecological, palaeoenvironmental, and palaeoclimatic conditions of the new palaeobotanical data. Additionally, there was undertaken an extensive comparative study of Gzhelian (Stephanian C–early Autunian) age macrofloras from different localities of Europe and North America. Together with these results, a significant macrofloral biostratigraphic gap for the Kasimovian stage in the Appalachian region (West Virginia, USA) is demonstrated to be correlated to the Late Pennsylvanian of Portugal, and its palaeogeographic significance is assessed.

Circulation weather types associated with extreme flood events in Northwestern Mediterranean

ABSTRACTThe aim of this work was to identify the circulation weather types associated with flood events that occurred in Catalonia (Northeastern Spain) during the period 1900–2010. To achieve this objective, 261 extraordinary and catastrophic flood and flash flood events that were recorded during this period were characterized and classified based on impact data. A preliminary analysis of maximum precipitation and discharge was conducted in order to have some quantitative hydrometeorological indicators associated with these kinds of events. The objective classification developed by Jenkinson and Collison, which is based on differences in synoptic patterns according to surface pressure, was implemented. Once the weather regimes for each flood event had been established, a statistical and comparative analysis was performed that allowed us to determine which synoptic patterns were more frequently associated with the different flood types, their differences and their similarities. The results show that most synoptic situations were pure cyclonic structures, in both extraordinary and catastrophic events, although they were more frequent in the latter. Catastrophic floods generally had a synoptic origin enhanced by certain mesoscale factors, while extraordinary floods were usually associated with local flash floods that occurred primarily in summer and early autumn, highlighting the undetermined types that were not reflected at a synoptic scale. As the Mediterranean basin is a region where floods cause serious socio‐economic impacts, this work will help improve prevention measures and provide information for policymakers, mainly for land‐use planning and early warning systems.

Rival framings: A framework for discovering how problem formulation uncertainties shape risk management trade‐offs in water resources systems

AbstractManaging water resources systems requires coordinated operation of system infrastructure to mitigate the impacts of hydrologic extremes while balancing conflicting multisectoral demands. Traditionally, recommended management strategies are derived by optimizing system operations under a single problem framing that is assumed to accurately represent the system objectives, tacitly ignoring the myriad of effects that could arise from simplifications and mathematical assumptions made when formulating the problem. This study illustrates the benefits of a rival framings framework in which analysts instead interrogate multiple competing hypotheses of how complex water management problems should be formulated. Analyzing rival framings helps discover unintended consequences resulting from inherent biases of alternative problem formulations. We illustrate this on the monsoonal Red River basin in Vietnam by optimizing operations of the system's four largest reservoirs under several different multiobjective problem framings. In each rival framing, we specify different quantitative representations of the system's objectives related to hydropower production, agricultural water supply, and flood protection of the capital city of Hanoi. We find that some formulations result in counterintuitive behavior. In particular, policies designed to minimize expected flood damages inadvertently increase the risk of catastrophic flood events in favor of hydropower production, while min‐max objectives commonly used in robust optimization provide poor representations of system tradeoffs due to their instability. This study highlights the importance of carefully formulating and evaluating alternative mathematical abstractions of stakeholder objectives describing the multisectoral water demands and risks associated with hydrologic extremes.

Large-scale modification of submarine geomorphic features on the Cascadia accretionary wedge caused by catastrophic flooding events

Large-scale modification of submarine geomorphic features on the Cascadia accretionary wedge caused by catastrophic flooding events

Does flooding effect the apparent survival and body condition of a ground foraging migrant passerine?

Natural disturbances play a fundamental role in maintaining habitat and landscape heterogeneity; however, these events can also have negative effects on some species. While we know that disturbances can reduce habitat quality for many species, leading to diminished populations and altered community structure, the effect of these events on individuals that continue to occupy affected areas remains unknown. We focused on understanding the impact of flood-mediated reduction of habitat quality on Swainson’s Warblers (Limnothlypis swainsonii). In 2008, a catastrophic flood event occurred on the Mississippi River and its tributaries, severely affecting one of two locations where we had studied territorial males since 2004. To determine the impact of flooding on this species, we evaluated how body condition and apparent survival of males differed between locations and in pre-flood (2004–2007) and post-flood (2008–2010) periods. Body condition did not differ between locations after the flood, suggesting that flooding did not cause food limitation for this obligate ground forager. Apparent survival in the post-flood period was lower at both locations and led to near population extirpation at the heavily flood-impacted site. Overall, this study demonstrates the vulnerability of species to extreme hydrological events, an increasing threat due to climate change. Future research should focus on identifying species that are vulnerable to these events and determining appropriate conservation strategies. Conservation for the Swainson’s Warbler should focus on identifying and conserving the highest elevation, least flood prone areas within bottomland hardwood forests and managing those areas for thick understory vegetation.