Flood Chronology Research Articles

Gauged and historical abrupt wave front floods (‘walls of water’) in Pennine rivers, northern England

AbstractExtremely rapid rates of rise in level and discharge in a subset of flash floods (‘abrupt wave front floods’, AWF) are separate hazards from peak level. Such flood events are investigated for Pennine catchments in northern England using both gauged and historical information. Gauged level and flow digital records at 15‐min intervals provide recent data. Historical information for 122 AWF events is extracted from a chronology of flash floods for Britain. Historical AWF events are mapped and found to occur on every major Pennine catchment; catchment descriptors are derived as a basis for assessing catchment vulnerability. We discuss the disputed origin of AWF. Using gauged data, we contrast the rising limb of AWF and ‘normal’ floods. We investigate time series of historical AWF, noting a puzzling peak in the late 19th century. Current rainfall and river monitoring does not provide a reliable basis for understanding AWF processes or for operational response and we suggest improvements. Similarly, current models for design flood estimation and forecasting do not generate the observed rapid increase in level in AWF floods.

The NADI Mathematical Model on the Danger Level of the Bili-Bili Dam

The research discusses the NADI mathematical model due to the overflow of the Bili-Bili dam, using secondary data obtained through online literature review by collecting various information related to the Bili-Bili Dam, starting from the Jeberang River Scheme, the chronology of floods, normal or dry conditions, and dam operation patterns. The aim of this study is to predict the level of danger of Bili-bili dam overflow over time, considering extreme weather factors and standard operating procedures performed by humans. The research uses analytical and computational methods. The study obtained the NADI mathematical model due to the overflow of the Bili-Bili dam, with two equilibrium points: (1) the equilibrium point free of disaster, (2) the disaster equilibrium point, and a basic disaster reproduction number of R0 = 1.219. This indicates that the water discharge from the dam is high and has an impact on the overflowing water for communities around the Jeneberang river. Therefore, it can be concluded that the NADI model can be used to simulate the Bili-bili dam process based on extreme weather and dam SOP, and predict the level of danger of Bili-bili dam overflow, which is also a novelty that has not been done in previous studies.

Chronology and paleoclimatic implications of the upper Ganga catchment floods since Marine Isotopic Stage-2

The present study aims at understanding the chronology and pattern of extreme flood events in the upper Ganga catchment. Towards this, we explored relict alluvial sequences, particularly the sand bodies overlying the fluvial gravels and underlain by the source proximal alluvial fans and debris flows, supported by geochemistry, and optical chronology. Based on the accretionary pattern of sand bodies, the progressive increase in the flood magnitude since the beginning of Marine Isotopic Phase-2 (MIS-2) has been identified. The oldest flood is dated to 30 ± 4 ka and the subsequent floods are dated to the post-glacial transitional climate (16 ± 4 ka) and during the early Holocene (between 14 ± 2 ka and 12 ± 2 ka), and the late mid-Holocene (7 ± 1 ka). Based on the temporal changes in the major element geochemistry (detrital and weathering proxies) the study indicate that during early to mid-MIS-2, the upper Ganga catchment witnessed high frequency-low magnitude floods. Further, the absence of flood sediment, the development of calcrete, and a sharp decrease in the detrital proxies, a significant reduction in high-magnitude floods during the Last Glacial Maximum (LGM) is inferred. The isotopic fingerprinting, based on 87Sr/86Sr and ɛNd(0), indicates that the majority of the floods during the MIS-2 originated from the Higher Himalayan lithologies, whereas the inner Lesser Himalayan lithology dominates the mid to late Holocene floods. Climatically, the floods were triggered neither during too-wet nor too-dry climatic conditions, but instead during the transitional climate caused due to the mesoscale atmospheric coupling between Indian Summer Monsoon (ISM) and mid-latitude westerlies.

A new flood chronology for KwaZulu-Natal (1836–2022): the April 2022 Durban floods in historical context

ABSTRACT In April 2022, flooding and associated geohazards caused major loss of life and extensive damage in the greater Durban region and large areas of the KwaZulu-Natal (KZN) coastal zone. Heavy rainfall that triggered the flooding and mass movement events was reported in national and international media as having ‘smashed weather records’. However, no systematic and up-to-date flood record exists for KZN to allow the April 2022 floods to be viewed within their full historical context. This study presents an historical geographic account of flooding in KZN, with a particular focus on the greater Durban region. The flood record expands upon available databases held by the South African Weather Service, drawing on missionary accounts, newspapers and personal diaries to identify all significant flood events in KZN since the mid-nineteenth century. We document 53 significant flood events from 1850-1899 (average ~1.1 per annum) and 210 from 1900-2022 (average ~1.7 per annum). Within the limits of our data, we suggest that the frequency of flooding in Durban has likely doubled over the last century. Our research confirms that the April 2022 floods were likely the most catastrophic natural disaster yet recorded in KZN, in collective terms of lives lost and overall economic impact.

Incorporating alluvial hydrogeomorphic complexities into paleoflood hydrology, magnitude estimation and flood frequency analysis, Tennessee River, Alabama

• Improvements to paleoflood hydrologic methods for alluvial rivers are explored. • Minimum paleodischarges were estimated using deposit d90 grain sizes. • Flood deposit depths were used to adjust channel geometries to reflect aggradation. • Paleodischarge estimation methods applicable to rivers lacking streamflow records. • Paleoflood record length and ‘completeness’ impacted flood frequency estimates. Extreme floods are underrepresented in stream gauge records. Sedimentological evidence of past floods (paleofloods) yields longer records, allowing extreme floods to be examined over several Holocene climate periods. This study examines the influence of hydrogeomorphic complexity (floodplain aggradation and spatially variable flood deposition) on paleoflood record “completeness” and their implications for flood magnitude estimates made with paleoflood hydrologic data. We collected two sediment cores 500 m apart from the same elevation on a natural levee along a bank of the Tennessee River near Guntersville, Alabama. We measured grain size from each core at a 1-cm resolution using a Malvern 3000 laser granulometer. Optically stimulated luminescence dating of flood deposits revealed approximate age ranges of 50 – 6500 years calibrated before present (yrs. B.P.) for the downstream 3.5 m core (i.e., BO1) and 190 – 8500 yrs. B.P. for the upstream 4.18 m core (i.e., EL2). First, a sensitivity analysis revealed adjusted floodplain elevations (AFE) for each paleoflood cross-sectional geometry to reflect floodplain aggradation over time enabled the detection of paleoflood magnitude differences, suggesting floodplain aggradation should be considered in paleoflood reconstruction within alluvial settings. Minimum paleodischarge intervals were estimated in a 1D HEC-RAS step backwater model by calculating the minimum paleoflood stage needed to transport the d90 of each paleoflood deposit. Big Oak and East Levee 2 sediment cores each contained 15 high magnitude, identifiable paleofloods. The majority of the BO1 paleofloods occurred in the last 2,000 years, while most EL2 paleofloods occurred between 2,000 and 5,000 yrs. B.P., suggesting localized geomorphic complexity produced distinct paleoflood records for the same hydrogeomorphic surface. Four paleoflood events correlate across the two cores based on their ages and grain size distributions, and we combined these four floods to create a ‘harmonized’ flood chronology for the site. The timing of these four floods corresponds with paleofloods that occurred in the last 2000 years in the middle section of the Tennessee River identified by prior paleoflood hydrologic studies. Flood frequency analysis (Bayesian Markov Chain Monte Carlo method) scenarios with ten configurations of paleoflood hydrologic data revealed differences in the number and timing of paleofloods in three paleoflood chronologies (BO1, EL2, and the harmonized) resulting from hydrogeomorphic complexities affected model distribution parameters, goodness-of-fit, and the estimated discharges of annual exceedance probabilities used to inform the design of critical flood infrastructure. As a consequence of longer records containing smaller floods, the estimated discharge of the 0.01 (100-yr), 0.001 (1000-yr), and 0.0001 (10,000-years) AEPs for EL2 were 16%, 11%, and 5% smaller, respectively, than BO1 estimates. Alluvial rivers present more challenges for reconstructing paleoflood records than bedrock, confined channel settings. The strategies presented in this paper can help integrate paleoflood hydrologic data into flood frequency analyses for alluvial rivers identifying and minimizing error stemming from hydrogeomorphic complexity. These strategies offer opportunities to expand the use of paleoflood hydrologic data in flood frequency analyses to include more rivers located in temperate environments where climate change is intensifying precipitation and a compelling need exists to anticipate and plan for changes in extreme flood occurrence.

Professor Kenneth John Gregory (1938–2020): The career, contributions and legacy of an eminent geographer and fluvial geomorphologist

AbstractThis paper provides the editorial to accompany a Special Issue of Earth Surface Processes and Landforms produced to honour the memory of Professor Ken Gregory, a key figure in late 20th‐ and early 21st‐century geography and geomorphology. It provides an overview of Ken Gregory's career in research, teaching, and university administration, and elaborates on his key research contributions and legacy across geography and geomorphology. Ten interrelated research themes are identified where Ken made particular impacts: (1) river catchment processes and process–form relationships; (2) wood in rivers; (3) anthropogenic impacts on rivers and catchments; (4) approaches to river management that better respect natural processes; (5) public perceptions of rivers; (6) quantitative palaeohydrology; (7) chronology of river floods and deposits; (8) key physical geography/geomorphology concepts and their metrics; (9) the nature of the discipline of physical geography; and (10) concepts in physical geography teaching. These themes provide a framework to introduce the papers in this Special Issue. Through his publications, leadership style, personality, and positive influence on the many people with whom he interacted, Ken Gregory has left a legacy that will continue to inspire present and future generations of geographers and geomorphologists.

Noachic traditions in the Book of Parables: Two parallels from the Dead Sea Scrolls

This note draws attention to two passages from the so-called Noachic interpolations in the Book of Parables where Noah traditions embedded in Qumran scrolls may provide helpful parallels. First, it suggests that the dating of the vision in 1 En. 60:1 is illuminated by a comparison to the Flood chronology in 4Q252. Second, it points out a similar use of Isa 24:18–20 in 1 En. 65:1–5, 9 and 4Q370. In both instances, the suggested parallels highlight the Parables’ use of the Flood as a prototype of an eschatological judgment.

A historical flash flood chronology for Britain

AbstractThe chronology provides a record of flash flood events in Britain based on data collated mainly between 1700 and 2020. The primary purpose of the chronology is to improve the risk assessment of flash floods of given magnitude. It is divided into 18 regions of the country and contains descriptions of nearly 8000 events. It extends a previous chronology covering northern and southwest England which is provided as an online resource in (http://ceg-fepsys.ncl.ac.uk/outputs/). Flash floods have had a variety of previous definitions but are here defined in terms of the speed of onset which can apply to both river floods and surface water floods. The chronology for the first time provides a comprehensive list of surface water floods and their recorded impact on cities, towns and villages. It also draws attention to the prevalence of very rapid rates of rise in river level either as ‘walls of water’, or at a rate likely to endanger life as a result of intense rainfall. Nearly 300 such events have been identified mainly in upland areas of northern England, Wales and Scotland. Practical and theoretical issues with respect to flood risk assessment and warning are discussed. The chronology is available to download and is hosted onhttps://www.jbatrust.org/how-we-help/publications-resources/rivers-and-coasts/uk-chronology-of-flash-floods-1/

Intra-annual dendrogeomorphic dating and climate linkages of flood events in headwaters of central Europe

Unlike large rivers, floods in headwaters have been poorly documented despite the fact that greater discharges are expected in such areas due to ongoing rainfall intensification. The purpose of this study is to carry out intra-annual dating of past floods combined with analysis of their climate linkages which may point on distribution and origin of floods. To this end, we applied dendrogeomorphic dating of impact scars on riparian vegetation to provide flood chronologies in twelve headwaters of eastern Czechia and determined their seasonal occurrences. Furthermore, we analyzed the precipitation indices and evaluated the flood events using reanalysis of pressure fields and the climate oscillation indices, particularly those representing the North Atlantic, Scandinavian, and East Atlantic/Western Russian patterns. Based on 434 dated trees, we identified 22–31 flood event years in each region over the last 70 years. The most frequent floods occurred from May to July. In addition, in ten event years it was possible to identify multiple flood events: for example May and July–August floods in 2010, 2014, and 2016. The monthly precipitation showed the strongest, but still weak, correlation with indices of Scandinavian climate oscillation during summer months (Rs = 0.23–0.42; p < 0.00), suggesting the influence of a blocking anticyclone over Scandinavia and wet air propagation to central Europe. This finding was also confirmed by the most frequent positions of low-pressure centers located east of the study sites except for the region with western orographic enhancement. In addition, timing shift of extreme precipitation to earlier period was identified at two out of three regions. We conclude that intra-annual dating of floods supported by analyses of climate extremes provides new data from sparsely gauged headwaters, thereby supplementing the information on possible changes in flood occurrences during ongoing climate change.

Chronology and sediment provenance of extreme floods of Siang River (Tsangpo‐Brahmaputra River valley), northeast Himalaya

AbstractThis study explores paleoflood deposits of the Siang River, known as the Tsangpo in Tibet. The river that often experiences large floods brings down huge amount of sediment and water that adversely affect the downstream regions with large human populations in the states of northeast Himalaya and its foreland. Along it's ~300 km mountainous stretch we collected samples for sedimentological, petrographic and Sr–Nd isotopic study to explore sediment provenance and dated the paleofloods (via optically stimulated luminescence, OSL). Geomorphic indices including precipitation and a geomorphic swath profile across the Brahmaputra catchment were studied to understand the interplay of mountain relief and rainfall that determine potential zones of high erosion and sediment supply. The OSL technique indicated the Siang River experienced at least eight large floods between 7 and 1 ka, possibly under the influence of warm and wet climatic conditions. The petrographic and isotopic data suggests that the eastern Himalayan syntaxis, which has the highest uplift and exhumation rate in the area, is not always the highest sediment producing zone. In some instances, the Tibetan plateau produces higher fluxes of sediments via glacial and landslide lake outburst floods (GLOFs and LLOFs). © 2020 John Wiley &amp; Sons, Ltd.

Early Medieval Place-Names and Riverine Flood Histories: A New Approach and New Chronostratigraphic Records for Three English Rivers

Environmental information from place-names has largely been overlooked by geoarchaeologists and fluvial geomorphologists in analyses of the depositional histories of rivers and floodplains. Here, new flood chronologies for the rivers Teme, Severn, and Wye are presented, modelled from stable river sections excavated at Broadwas, Buildwas, and Rotherwas. These are connected by the Old English term *wæsse, interpreted as ‘land by a meandering river which floods and drains quickly’. The results reveal that, in all three places, flooding during the early medieval period occurred more frequently between AD 350–700 than between AD 700–1100, but that over time each river's flooding regime became more complex including high magnitude single events. In the sampled locations, the fluvial dynamics of localized flood events had much in common, and almost certainly differed in nature from other sections of their rivers, refining our understanding of the precise nature of flooding which their names sought to communicate. This study shows how the toponymic record can be helpful in the long-term reconstruction of historic river activity and for our understanding of past human perceptions of riverine environments.

Recent flood hazards in Kashmir put into context with millennium-long historical and tree-ring records

In September 2014, the Kashmir valley (north-west India) experienced a massive flood causing significant economic losses and fatalities. This disaster underlined the high vulnerability of the local population and raised questions regarding the resilience of Kashmiris to future floods. Although the magnitude of the 2014 flood has been considered unprecedented within the context of existing measurements, we argue that the short flow series may lead to spurious misinterpretation of the probability of such extreme events. Here we use a millennium-long record of past floods in Kashmir based on historical and tree-ring records to assess the probability of 2014-like flood events in the region. Our flood chronology (635 CE–nowadays) provides key insights into the recurrence of flood disasters and propels understanding of flood variability in this region over the last millennium, showing enhanced activity during the Little Ice Age. We find that high-impact floods have frequently disrupted the Kashmir valley in the past. Thus, the inclusion of historical records reveals large flood hazard levels in the region. The newly gained information also underlines the critical need to take immediate action in the region, so as to reduce the exposure of local populations and to increase their resilience, despite existing constraints in watershed management related to the Indus Water Treaty.

Flash flood reconstruction in the Eastern Mediterranean: Regional tree ring-based chronology and assessment of climate triggers on the island of Crete

The past geomorphic activity of flash floods in the Eastern Mediterranean has been poorly understood. Despite the general increase in mean annual temperature and decrease in annual precipitation totals, intense rainfall during strong cyclogenesis is still expected under a changing climate. The aim of this study was to identify past flash flood events on the island of Crete (Greece) to (i) create a regional chronology of flash floods using dendrogeomorphic dating and (ii) describe climate triggers responsible for the most distinct events. The sampling of 398 trees and shrubs from eight catchments enabled the reconstruction of 76 flash flood events over 43 different years. The length of the chronologies ranged from 27 to 125 years, and the most distinct events were recorded in the 1993–94, 2000–01, and 2006–07. Significant differences (p < 0.00001) in the ages of sampled trees and the bark thickness among the catchments resulted in different lengths of chronologies and numbers of identified events. Records from selected rain gauges were used to identify precipitation patterns associated with flash floods. The low propagation velocities of cyclones originating south and west of Crete characterised the most distinct flash flood events, based on synoptic scale analyses.

A record of flooding on the White River, Arkansas derived from tree-ring anatomical variability and vessel width

ABSTRACTTree rings preserve important records of past flooding. We present the results of an examination of inter-annual tree-ring anatomical variability and vessel width in overcup oak (Quercus lyrata) and river flooding at a bottomland hardwood forest site near the confluence of the White and Mississippi Rivers. We developed two flood chronologies based on (1) visual identification of “flood-ring” anatomical anomalies and (2) a simple method for quantitative measurements of earlywood vessel width (VW). Using visual flood rings, we have developed a response index (RI) chronology of floods from 1780–2013 and, using the VW measurements, we have developed a quantitative reconstruction of spring river levels from 1800–2013. Both the RI and VW chronologies are strongly related to spring river flooding and indicate that major floods such as those in 1805, 1826, 1844, 1852, 1858, occurred in the period prior to the systematic collection of stage data, and that the frequency of extreme events has greatly varied over the past two centuries. These chronologies provide important new information about Lower Mississippi River flooding in past centuries, and our simple method of measuring VW is a potentially useful new approach to the development of tree-ring records of flooding.

Retention of alluvial sediment in the tidal delta of a river draining a small, mountainous coastal watershed

Small mountainous coastal watersheds are thought to be responsible for transporting disproportionately large volumes of sediment to the global ocean. In comparison with low-relief passive margin rivers, their geologic setting is associated with high rates of sediment production, high peak flows due to uniformity in runoff lag-times, and limited floodplain development. However, mountainous watersheds are often associated with estuarine deltas, and because the stream gauges used to calculate water and sediment fluxes tend to be located above the head of tides, the relative magnitude of sediment discharged to the ocean vs. retained in deltas is uncertain. The aim of this study was to determine the estuarine trap efficiency for the Salinas River in central California (USA), a watershed known both for its extremely high rate of sediment production and its extensive lowland delta, thereby helping to resolve the role of estuarine deltas in ocean sediment discharge. Sediment retention rates were calculated for the Late Holocene, using soil maps to estimate the areal extent of the delta prior to land reclamation, and radionuclide, pollen, pollution, and flood chronologies in concert with sediment bulk density measurements to constrain deposition rates. Results suggest that less than 1% of the sediment delivered to the coastal zone by the river was retained in the estuarine delta. Deposition rates distant from distributary channels matched long-term rates of sea level rise, suggesting that the formation of accommodation space acted as a primary control on sediment accretion. However, along tidal-fluvial distributary channels, accretion rates were much greater, and discrete flood layers were present, suggesting that accretion along distributaries was driven by flood events. In addition, long-term variability in sediment accretion rates broadly matched other records of alluvial flooding in central and southern California, suggesting that high precipitation intervals leave an imprint – although subtle – in the sedimentary record of estuaries. By documenting high sediment discharge to the ocean (99% of fluvial load), this study highlights the importance of small mountainous watersheds in global oceanic sediment transport, and further emphasizes the joint roles of accommodation space formation and sediment supply in controlling rates of estuarine sediment accretion.

Historical flash floods in England: New regional chronologies and database

There is increasing interest in past occurrences of flooding from intense rainfall, commonly referred to as “flash flooding,” and the associated socioeconomic consequences. Historical information can help us to place recent events in context and to understand the effect of low frequency climate variability on changing flash flood frequencies. Previous studies have focussed on fluvial flooding to reconstruct the temporal and spatial patterns of past events. Here, we provide an online flood chronology for the north and south‐west of England for flash floods, including both surface water and fluvial flooding, with coverage from ~1700 to ~2013 (http://ceg-fepsys.ncl.ac.uk/fc). The primary source of documentary material is local newspaper reports, which often give detailed descriptions of impacts. This provides a new resource to inform communities and first responders of flood risks, especially those from rapid rise in water level whose severity may be greater than those of accompanying peak flow. Examples are provided of historical flash floods that exemplify how the chronologies can help to place recent floods in the context of the preinstrumental record for: (a) more robust estimates of event return period, (b) identification of catchment or settlement susceptibility to flash flood events, and (c) characterisation of events in ungauged catchments.

Flood hazard assessment of the Kashmir Valley using historical hydrology

Studies aimed at reconstructing the chronology of historical floods in a region assume an important role in flood hazard assessment, especially for flood prone regions like the Kashmir Valley. This is usually done through the review of historical documents and/or palaeohydrological studies; the latter allows access far beyond historical records. While as, archival scribes offer particularly valuable insights into attributes of hydrological extremes in the recent past. The Kashmir Valley has contours of its own in the field of historical hydrology, hitherto scattered across multiple textual scribes, making them obscure. Nevertheless, information collated and analysed made these contours visible in a specific way. The critical evaluation of historical flood records revealed that the Kashmir Valley was beleaguered with a series of catastrophic inundations. In addition, calibration of historical records against instrumental data spanning for ~1400 years were linked to quantifiable attributes to simulate their discharge, water surface elevation, and spatial extent using the Hydrologic Engineering Center's (HEC) River Analysis System (RAS) program. The deliverables of this study are expected to be valuable for flood hazard mitigation in the Kashmir Valley and for further research in this direction.

Magnitude and chronology of extreme floods in the last 2 ka based on the stratigraphy of a riverine archeological site (Schurovo settlement, middle Oka River, Central European Russia)

Magnitude and chronology of extreme floods in the last 2 ka based on the stratigraphy of a riverine archeological site (Schurovo settlement, middle Oka River, Central European Russia)

Storm-generated Holocene and historical floods in the Manawatu River, New Zealand

This paper reports the first reconstruction of storm-generated late Holocene and historical river floods in the North Island of New Zealand. The sedimentary infills of nine palaeochannels were studied in the lower alluvial reaches of the Manawatu River. Floods in these palaeochannels were recorded as a series of sand-rich units set within finer-grained fills. Flood chronologies were constrained using a combination of radiocarbon dating, documentary sources, geochemical markers, and palynological information. Flood units were sedimentologically and geochemically characterised using high resolution ITRAX™ X-Ray Fluorescence (XRF) core scanning and laser diffraction grain-size analysis. The longest palaeoflood record extends back ca.3000 years. The temporal resolution and length of the Manawatu record reflects accommodation space for fluvial deposits, channel dynamics and mobility, and high sediment supply. Floods that occurred in the Manawatu during the mid-1800s at the time of European land clearance and in the first decade of the twentieth century appear to be among the largest recorded in the last 3000 years.

A Flood Chronology for Cork City and its Climatological Background

A flood chronology for the city of Cork is presented for the period 1841 -1988. The 292 floods which are reported are classified into six flood types primarily based on the relative role of rainfall and tidal conditions in each flood event. Changes over the 148 years in flood frequencies and flood types are outlined and assessed, primarily with respect to the significance of the atmospheric circulation patterns and wind direction, but also with reference to the occurrence of river discharge levels and tidal surges. The major cause of flooding is shown to be excessive rainfall, although high tides are also of considerable significance, especially those accompanied by storm surges.