Extraordinary Floods Research Articles

Extraordinary floods related to the climatic event at 4200 a BP on the Qishuihe River, middle reaches of the Yellow River, China

Palaeo-hydrological study was carried out in the Qishuihe River valley in the middle reaches of the Yellow River. Several bedsets of flood slackwater deposit were identified in the Holocene loess-soil sequences on the riverbanks. They were differentiated from aeolian loess and soils by the parallel and waving beddings and the distinctive stratigraphic breaks separating individual palaeoflood events. Chronology of the flood events was established by OSL dating, checked by archaeological identification of the anthropogenic remains retrieved from the sequences. The results show that successive floods occurred between 4300 and 4000 a BP in association with the abrupt climatic event of 4200 a BP. These overbank floods had the riverbank settlement inundated repeatedly. Another series of extraordinary floods occurred between 3200 and 3000 a BP when monsoonal climate shifted from the mid-Holocene Climatic Optimum toward late Holocene dry conditions. The climatic event of 4200 a BP and the climatic decline at 3100 a BP were believed to be characterized by droughts previously. This work provides solid evidence that both severe droughts and extreme floods were parts of the climatic variability during abrupt climatic event and climatic decline in the semi-arid to sub-humid zones over the world.

Extraordinary Floods of 4100−4000 a BP recorded at the Late Neolithic Ruins in the Jinghe River Gorges, Middle Reach of the Yellow River, China

Holocene palaeohydrological investigations were carried out in the middle reach of the Jinghe River that drains the central part of the Loess Plateau. A set of palaeoflood slackwater deposits was found interbedded in the Holocene loess-soil sequence within the cliff riverbanks. Both the sedimentary criteria and the analytical results show that this sediment was sourced from a suspended sediment load of floodwater. The major cultural layer of a late Neolithic settlement (4300−4000 a BP) occurring at the same site is blanketed by this flood deposit directly. Slopewash with pottery shards, charcoal and burnt earth occurs in between the palaeoflood slackwater deposit beds. It indicates that each of the slackwater deposit beds has recorded one individual flood event, and that these extraordinary floods occurred when the late Neolithic people occupied the riverbank terrace land. This pre-historical settlement was abandoned after the floods eventually due presumably to repeated inundation by overbank floodwater. The flood events were OSL dated to between 4100 and 4000 a BP and checked by archaeological dating of the anthropogenic remains retrieved from the sequences. Peak discharges of the floods were estimated to between 19,500 and 22,000 m 3 s − 1 , which is several times gauged maximum floods. During the 4200–4000 a BP climatic event, severe droughts were documented in China's monsoonal regions and great floods were known from an ancient legend. This study provides a well-dated sediment record of pre-historical floods which occurred at the transition from the Neolithic to the Bronze Age in the Yellow River basin. It shows that extraordinary floods were part of the abrupt climatic variability during the 4200−4000 a BP climatic event. The highly variable, unstable and catastrophic climate typified by both droughts and floods resulted in settlement abandonment, and possibly the decline of the highly developed late Neolithic civilizations in China's monsoonal regions.

Bayesian MCMC approach to regional flood frequency analyses involving extraordinary flood events at ungauged sites

summary This paper proposes a method for using major flash flood events occurred at ungauged catchments to reduce the uncertainties in estimating regional flood quantiles. The approach is based on standard regionalization methods assuming that the flood peak distribution rescaled by a site-dependent index flood is uniform within a homogeneous region. A likelihood formulation and a Bayesian Markov Chain Monte Carlo (MCMC) algorithm are used to infer the parameter values of the regional distributions. This statistical inference technique has been selected for its rigorousness – various hypotheses are explicitly formulated in the likelihood function, its flexibility as for the type of data that can be treated, and its ability to compute accurate estimates of the confidence intervals for the adjusted parameters and for the corresponding flood quantiles. The proposed method is applied to two data sets from Slovakia and the South of France that consist of series of annual peak discharges at gauged sites and estimated peak discharges of extreme flash flood events that have occurred at ungauged sites. The results suggest that the confidence intervals of the quantiles can be significantly narrowed down provided that the set of ungauged extremes is the result of a comprehensive sampling over the selected region. This remains valid, even if the uncertainties in the estimated ungauged extreme discharges are considered. The flood quantiles estimated by the proposed method are also consistent with the results of site specific flood frequency studies based on historic and paleoflood information.

Palaeoflood Records from Upper Kaveri River, Southern India: Evidence for Discrete Floods During Holocene

Palaeoflood Records from Upper Kaveri River, Southern India: Evidence for Discrete Floods During Holocene A record of six discrete middle Holocene floods has been established based on sedimentological and stratigraphical studies in the upper Kaveri catchment at Siddapur. The flood events are represented by six discrete, sharp-bounded, sand-silt couplets. Texturally and geochemically the suite of couplets is quite distinct from the overlying and underlying structureless fluvial deposits. Based on OSL ages the suite of couplets cover the Holocene from ~8 to ~2 ka. Such evidence is not present or reported from any other river originating in the Western Ghat in the Indian Peninsula. We argue that the six couplets represent short-term, high discharge events or flash floods. The initiation of this phase of flash floods broadly corresponds with the southward migration of ITCZ and a gradual decline in Indian summer monsoon precipitation starting at ~7.8 ka. Comparison of the elevation of the highest couplet with the high flood level (HFL) of the 1961 extraordinary flood on Kaveri demonstrates that the 20th century flood was higher than the mid-Holocene palaeofloods.

Changes in phytoplankton morpho-functional groups induced by extreme hydroclimatic events in the Middle Paraná River (Argentina)

The extreme hydrological fluctuations in the South American Parana River are unequivocally coupled with El Nino-Southern Oscillation’s (ENSO’s) global climatic phenomenon. In order to identify phytoplankton changes triggered by periods of extraordinary flood (November 1997–1998) and drought (November 1999–2000), the main channel of the Middle stretch was monthly analysed and compared with neutral hydrological conditions (November 1977–1978). These results show that water discharge plays a stirring role on phytoplankton dynamics, and that light availability acts as an important selective force. Phytoplankton transport, density, and biovolume were lower during El Nino and higher during La Nina (P < 0.01). A great development of small flagellate unicells belonging to morpho-functional groups Y (Cryptomonas spp.) and X2 (Chlamydomonas spp., Plagioselmis nannoplanctica and small Cryptophyceae) prevailed during both anomalous periods, accompanied by small centric diatoms and Skeletonema cf. potamos (D). This scenario significantly differs from those encountered during neutral conditions, where codon P (Aulacoseira granulata) dominated. The absence of these large filaments during drought and flood peaks could be explained by sedimentation processes in low waters, and by organisms’ retention by obstacles after water displacement from the plain in high waters periods; however, the disruption of the inocula from floodplain areas to the main flow may be the most important factor in both periods. The hydroclimatic anomalies provoked changes in the phytoplankton structure of the Parana River, favouring X2 and Y functional groups instead of the typical P and C. The interruption of the constant feedback between the main channel and the floodplain water bodies due to low connectivity during droughts and the homogeneity of environment during floods, govern phytoplankton dynamics in this large river. The rapid occurrence of community reorganization after the conclusion of these events and the persistence of certain variations lead to the hypothesis that the magnitude and duration of extreme water discharges will determine the intensity and duration of changes.

하천 협소부에서 하상 이동성과 형태와의 상관성에 관한 하도수리학적 평가

Each river in each country has peculiar channel characteristics at every section. Korea consists of mountains at the rate of 70%. Due to this, the sections that display unique channel form are scattered. One of the typical features is the narrow pass of channel section that presents in the process of the generation of alluvial channel and deformation channel. Around as this narrow pass of channel, it often comes to be regular flood disaster section. Regardless of this situation, investigations and plans that reflect channel characteristics at the narrow pass of channel have been wholly wanting until now. In accordance with this, we have investigated and analysed hydraulic significance and channel form of the narrow pass of channel in Seonsan in this study. The study has found real minute classification of sediment phenomenon at river bed of low flow channel on investigation section which is sand-bed river, but it was vaguely difficult to conclude that classification of sediment arises from explicit natural force. We were able to assume that the phenomenon comes from gentle bed slope, supply of river bed materials which is nearly uniformity. However, classification of sediment would come from collecting an aggregate rather than natural force. And we found that compound cross section conversion has been developing dramatically with channel form of movable bed section referring to movement which was active before at drainage district of the narrow pass of channel. With this, we could find the phenomenon that river width of low flow channel diminished largely. This kind of situation implies that it may cause compound section weighting, flood dimension decreasing, revetment at low flow channel or the local scour at bottom of levee when extraordinary flood occurs.

Regional distribution of native and exotic species in levees of the lower delta of the Paraná river

The distribution and abundance of exotic and native species in levee neo-ecosystems were analyzed. No invasive species were found in unit A; their absence could be explained by the fluvial action of the Parana river, extraordinary flood episodes and anthropic disturbances. Invasive species associated with the tidal regimen of the de la Plata river were present in units B and C, particularly Chinese privet ( L. sinense ), green ash ( F. pennsylvanica ), honey locust ( G. triacanthos ), Japanese honeysuckle ( L. Japonica ), blackberry ( Rubus spp.), box elder ( A. Negundo ) and glossy privet ( L. Lucidum ).Native species showed low recovery values, both at a regional level and within each unit, with the exception of A. The neo-ecosystems with the greater degree of abandonment of units B and C exhibited dominance of exotic tree species and, to a lesser extent, recovery of native species of the original gallery forest (seibo, Erythrina crista galli ; laurel, Nectandra falcifolia ; canelon, Rapanea spp. and arrayan, Blepharocalyx tweediei ).

Extreme flood events favour floodplain mollusc diversity

Floods are fundamental for the maintenance of floodplain biodiversity. As a result, well-functioning floodplains are characterized by a high spatio-temporal heterogeneity. Most floodplain-organisms need this shifting landscape mosaic to fulfil their environmental requirements and display a range of adaptations to survive floods. However, in temperate areas, where winter floods are common, extraordinary floods occurring in summer, a period of high physiological activity, may seriously impact the floodplain fauna. This is especially true for guilds characterized by low mobility, such as molluscs. Here we examined the immediate and longer-term response of Elbe grassland molluscs to the extreme 2002 Elbe summer flood in terms of abundance, diversity, and community composition by comparing pre- and post-flood data collected with identical methods. The flood favoured the colonization of aquatic species and led to a shift of the community towards a more hydrophilic composition. Both diversity and abundance increased significantly in the first year following the flood but decreased later gradually to the pre-flood levels. The high spatio-temporal habitat heterogeneity played an important part in the maintenance of mollusc diversity by increasing refuge opportunities and favouring the maintenance of various mollusc communities with different environmental requirements within the floodplain.

가배수 터널을 이용한 이상홍수 대비 단면확보에 관한 연구

The object of this study is the safety insurance of the dam to provide for the extraordinary flood. The safety insurance of the reservoir was taken by the preparatory discharge using the temporary division tunnel used during the reservoir construction. In this study, the Sungju reservoir was simulated. The existing discharge facilities of the intake tower of the Sungju reservoir could nat have influence on the flood control. When the Sungju reservoir operated to begin preparatory discharge for 48 hrs by the temporary diversion tunnel that have discharge of an 20-years frequency, the water level was lowered about 20 cm. When the Sungju reservoir operated to begin the continuous discharge after the preparatory discharge, the water level was lowered over 1m but the downstream at risk was caused by the resulted. If it is possible to operate to begin the preparatory discharge of the reservoir for 24 hrs by the temporary diversion tunnel, that will improve the flood control faculty of the reservoir without other hydraulic structure and safety of the Sungju reservoir will be higher.

A half-a-century record of annual energy expenditure and geomorphic effectiveness of the monsoon-fed Narmada River, central India

Abstract This case study presents quantitative data on the magnitude and variability of specific power and total energy expenditure over a period of 51 years for the monsoon-dominated Narmada River, which produced an impressive flood of the order of 69 400 m 3 s − 1 in 1970. Daily specific stream power ( ω ) for a gauging site located in the lower Narmada Basin was estimated by using daily discharge data available from 1949 to 1999, at-a-station hydraulic geometry equations and the relationship between discharge and water surface slope. The total amount of energy expended per unit area by all the monsoon flows was estimated by integrating the area under the ω -graph. The estimates of effective stream power were then checked against work thresholds. The analysis reveals high total energy expenditure within the monsoon season (43 to 380 MJ) as well as during large floods (40 to 145 MJ). Extraordinary floods have about 20–60% share in the total monsoon energy expenditure. In general, the daily ω was found to be above the threshold of pebble-movement for 80% of the time within the monsoon season, implying high competence of monsoon flows. The Miller–Magilligan threshold for major modification of channel or fluvial landscape (300 Wm − 2 ) was exceeded on 10 occasions within the gauge period. The main conclusion is that in spite of high total energy expenditure and occurrence of multiple threshold-crossing events, the main task of the Narmada River is to convey sediments supplied from upstream area. The channel morphology appears to be adjusted to catastrophic floods that occur at an interval of more than a century.

Natural hazards in the Bavarian Alps: a historical approach to risk assessment

The Bavarian Alps region is strongly affected by various natural hazards, mainly hydrological events (floods, debris flows), geomorphic/geological events (landslides, rock falls), and avalanches. Extraordinary floods, like in 2002 or in the summer of 2005 in south Bavaria, have again posed the question of the possible extent and frequency of recurrence of catastrophic events. To put risk assessment on a broader basis historical data about all kinds of past natural hazards were detected in the archives of local authorities and administrative offices for water management. More than 10,000 sources (written accounts, maps, and photographs) were collated in a database. The majority of this information reaches back to the middle of the 19th century. In addition, many documents referring to events dating back even as far as the middle age were found. The Historische Analyse von NaturGefahren (HANG, historical analysis of natural hazards) project at the University of Eichstaett mainly focuses on a small-scale examination of the data. Initial results of the data analysis show that most catastrophic events in the Bavarian Alps only affect parts of the area, but not the whole region. Therefore it is necessary to assess the risk potential on a local scale like valleys, the catchment areas of mountain streams, or even single streams. Firstly the presented data is aimed to help engineers in future planning of hazard-protection measures. Secondly the information can form a vital component to enhance our knowledge of hydrological and geomorphic/geological dynamics in the Alps.

An assessment of exceedance probabilities of envelope curves

Envelope curves are often used to provide summary accounts of our flood experience, but their operational use has been limited by our previous inability to assign to them an exceedance probability “EP.” General expressions are derived for the EP of an envelope curve at a particular site in a heterogeneous region, as well as measures of central tendency of EP across sites. Analytic results are reported for the case when floods follow a Gumbel or generalized extreme value distribution, and these results are contrasted with those of previous studies that sought to estimate the exceedance probability of extraordinary floods such as the flood of record (FOR) and the probable maximum flood (PMF). A case study involving FOR and PMF discharges for 226 rivers across the U.S.A. indicates that relatively consistent estimates of the average exceedance probability associated with both FOR and PMF envelope curves can be obtained using the theoretical approach introduced here.

The Palaeoflood record of the Gardon River, France: A comparison with the extreme 2002 flood event

A paleoflood study in the Gardon River gorge in southern France identified extreme floods larger than any modern or historically gauged flood. During the course of our study, an extreme flood on the 8–9th of September 2002 claimed the lives of 21 people and caused millions of Euros worth of damage to the towns and villages along the river. The magnitude of this flood was larger than any known historical flood on record,. However, there is evidence of greater magnitude flood events in the form of slack-water flood deposits preserved in caves elevated 17–19 m above the normal base flow, and up to 3 m above the level reached by the 2002 floodwaters. The stratigraphy and radiocarbon dating show that at least five extreme events occurred during the past 500 years. The discharge estimation associated with these flood units, achieved using the HEC-RAS one dimensional model, indicates that at least three floods were bracketed by discharges between 6850 and 7100 m 3 s − 1 , and at least two floods reached a magnitude above 8000 m 3 s − 1 . Therefore, the extraordinary flood of 2002 was not the largest in the basin.

Bank erosion history of a mountain stream determined by means of anatomical changes in exposed tree roots over the last 100 years (Bílá Opava River — Czech Republic)

The date of exposure of spruce roots as a result of bank erosion was investigated on the Bílá Opava River in the northeastern Czech Republic. Following the exposure of roots, wood cells in the tree rings divide into early wood and late wood. Root cells within the tree rings also become smaller and more numerous. These processes permit dating of the erosion episodes in which roots were exposed. Sixty root samples were taken from seven sampling sites selected on two riverbed reaches. The results of root exposure dating were compared to historical data on hydrological flooding. Using the root exposure dating method, several erosion episodes were recorded for the last 100 years. The greatest bank erosion was recorded as consequence of an extraordinary flood in July 1997. In the upper, rocky part of the valley studied, bank erosion often took place during large floods that occurred in the early 20th century. In the lower, alluvial part of the valley, erosion in the exposed roots was recorded only in 1973 and has been intensive ever since. It is suggested that banks in the lower part are more frequently undercut, which leads to the falling of trees within whose roots older erosion episodes were recorded. Locally, bank erosion is often intensified by the position of 1- to 2-m boulders in the riverbed, which direct water into the parts of the banks where erosion occurs. Selective bank erosion could be intensified by debris dams and hillslope material supply to the riverbed.

Dating of small gully formation and establishing erosion rates in old gullies under forest by means of anatomical changes in exposed tree roots (Southern Poland)

Small gullies occur in forested gully systems on the undulating loess plateau in southern Poland. The old gully hillslopes are mainly covered with 200-year old beech trees in contrast with the surface of the summit plateau, which is cultivated agricultural land. Beech roots are exposed in the gullies through erosion. Wood vessels in the root tree rings divide into early wood and late wood and, after the roots are exposed, start to make fewer vessels. These anatomical changes in root tree rings allow us to date erosion episodes. Small gullies form in a different manner on the valley floor and on hillslopes. In valley bottoms, erosion features are often formed at some distance from one another, and in time small gullies combine to form a single, longer one. Depending on local conditions, such as the hillslope profile, hillslopes may exhibit headward erosion or may be eroded downwards. Hilllope gullies may be transformed into side valleys as a result of gradual widening and deepening. Dating the exposure of roots indicates that small gullies had already formed in the valley system by 1949. Intensive gully erosion was recorded between 1984 and 2002, during intense precipitation in 1984 and, of particular note, during the extraordinary flood of 1997 which affected all of Central Europe. The mean rate of small gully erosion in the old gully system studied is 0.63 m/year. On hillslopes the mean gully erosion rate is 0.21–0.52 m/year, and on the valley bottoms 0.18–1.98 m/year. High bottom erosion rates resulted from the emergence of long gullies during the erosion episodes in 1984 and 1997. Sheet flow in valley floors intensifies at times of heavy rainfall which causes long gullies to form. Taking into account the fact that conditions favoured erosion, the rate at which the old gullies under forest were transformed should be considered slow. New side gullies form slowly within the valley and it appears that if erosion progressed at the rate observed, new side valleys would take a few hundred years to form.

Geomorphic effectiveness of extraordinary floods on three large rivers of the Indian Peninsula

The efficacy of extreme events is directly linked to the flood power and the total energy expended. The geomorphic effectiveness of floods is evaluated in terms of the distribution of stream power per unit boundary area ( ω) over time, for three very large floods of the 20th Century in the Indian Peninsula. These floods stand out as outliers when compared with the peak floods per unit drainage area recorded elsewhere in the world. We used flood hydrographs and at-a-station hydraulic geometry equations, computed for the same gauging site or a nearby site, to construct approximately stream-power curves and to estimate the total energy expended by each flood. Critical unit stream power values necessary to entrain cobbles and boulders were estimated on the basis of empirical relationships for coarse sediment transport developed by Williams [Williams, G.P., 1983. Paleohydrological methods and some examples from Swedish fluvial environments. I. Cobble and boulder deposits. Geografiska Annaler 65A, 227–243.] in order to determine the geomorphological effectiveness of the floods. The estimates indicate that the minimum power per unit area values for all three floods were sufficiently high, and stream energy was above the threshold of boulder movement (90 W m − 2 ) for several tens of hours. The peak unit stream power values and the total energy expended during each flood were in the range of 290–325 W m − 2 and 65–160 × 10 6 J respectively. The average and peak flood powers were found to be higher or comparable to those estimated for extreme palaeo or modern floods on low-gradient, alluvial rivers.

Seed deposition in drift lines during an extreme flooding event — Evidence for hydrochorous dispersal?

Extreme flooding events can be of major importance for dispersal processes in today's fragmented landscape. We studied long- and short-distance seed dispersal during an extraordinary flooding of the Elbe River in summer 2002. In addition we evaluated the effect of different species traits (seed buoyancy, dispersal type, Ellenberg moisture values) on dispersal and discussed the relevance of hydrochorous dispersal during extreme flooding events for nature conservation and restoration. Along a transect of 400 km of the Middle Elbe River (Eastern Germany) drift line material from three habitats (arable field, grassland, river bank) was collected at five locations. Its seed content was analysed and compared with vegetation communities of the same region with respect to species composition. One part of the drift line samples was scanned for seeds and seed fragments visually, while the other part was exposed for germination. A total of approximately 1500 seedlings of about 70 species emerged from the samples. The most frequent species were Deschampsia cespitosa , Urtica dioica, Ranunculus repens and Lycopus europaeus . Hand-sorting of drift-line material revealed that only 1.5% of the seeds occurring in the samples recruited in the germination trials. Although most seeds and seedlings from the drift line samples belonged to common species, some seeds of rare and endangered species were found. Species composition of the drift line samples differed only marginally between the studied habitats and locations, which is interpreted as evidence for short- and long-distance seed dispersal. In contrast, the vegetation of the analysed habitats differed significantly. The studied species traits did not differ between drift line material from different habitats, but rather between the differentiated vegetation communities. We conclude that seeds from different habitats and locations are transported together during heavy flooding and that these floodings might thus expand the usual dispersal ranges of plant species. Extreme Überflutungsereignisse können in unserer heutigen fragmentierten Landschaft von großer Bedeutung sein. Im Sommer 2002 haben wir nach Rückgang der “Jahrhundert-Flut” der Elbe hydrochore Nah- und Fernausbreitung pflanzlicher Diasporen untersucht. Zusätzlich wurde der Einfluss unterschiedlicher artspezifischer Charakteristika (Schwimmfähigkeit der Diasporen, Ausbreitungs-Typ, Ellenberg Feuchte-Werte) auf die Ausbreitung analysiert und die Relevanz hydrochorer Ausbreitung während extremer Überflutungen für den Naturschutz diskutiert. Entlang eines Transekts von insgesamt ca. 400 Flusskilometern der Mittleren Elbe (Ost-Deutschland) haben wir von jeweils drei Habitaten (Acker, Auen-Grünland, Flussufer der Elbe) an fünf Lokalitäten Spülsaummaterial entnommen. Wir untersuchten dessen Diasporengehalt und verglichen die Artenzusammensetzung des Spülsaums mit derjenigen charakteristischer Vegetationstypen derselben Region. Ein Teil der Spülsaumproben wurde visuell auf Diasporen durchsucht, während der übrige Teil zur Keimung ausgebracht wurde. Insgesamt liefen ca. 1500 Keimlinge von mehr als 70 Arten aus den Proben auf. Am häufigsten kamen Deschampsia cespitosa , Urtica dioica , Ranunculus repens und Lycopus europaeus vor. Das manuelle Sortieren des Spülsaummaterials ergab, dass nur ca. 1.5% der in den Proben enthaltenen Diasporen in den Keimungsuntersuchungen aufliefen. Obwohl die meisten Diasporen und Keimlinge aus den Spülsaumproben zu weit verbreiteten Arten gehörten, wurden einige Diasporen seltener und gefährdeter Arten gefunden. Die Artenzusammensetzung der Spülsaumproben unterschied sich nur geringfügig zwischen den untersuchten Habitaten und Lokalitäten, was als Hinweis sowohl auf Nah- als auch Fernausbreitungsprozesse gewertet wird. Im Gegensatz dazu unterschied sich die Vegetation der untersuchten Habitate signifikant. Die analysierten artspezifischen Charakteristika unterschieden sich nicht signifikant zwischen Spülsaummaterial verschiedener Habitate wohl aber zwischen den betrachteten Vegetationstypen. Wir schließen aus den Ergebnissen, dass während extremer Überflutungen Diasporen von Arten unterschiedlicher Habitate und Lokalitäten zusammen transportiert werden und dass derartige Überflutungen den normalen Ausbreitungsradius von Pflanzenarten ausweiten können.

Inventor, Entrepreneur, Rascal, Crank or Querulent?: Australia's Vexatious Litigant Sanction 75 Years On

Rupert Frederick Millane (1887-1969) was Australia's first declared vexatious litigant. An inventor, entrepreneur, land developer, transport pioneer and self-taught litigator, his extraordinary flood of unsuccessful litigation in the 1920s led Victoria to introduce the vexatious litigant sanction now available to most Australian superior courts. Once declared, a vexatious litigant cannot issue further legal proceedings without the leave of the court. Standing to seek the order is usually restricted to an Attorney-General. It is used as a sanction of 'last resort'. But who was Millane and what prompted his declaration in 1930? What does psychiatry have to say about the persistent complainant and vexatious litigant? How often is the sanction used anyway? What is its utility and the nature of the emerging legislative changes? Now, on the 75th anniversary of Millane's declaration, this article examines these issues.

Recovery and stability of Paraná river floodplain grasslands twenty years after a catastrophic flood

The floodplain herbaceous vegetation of the Parana River (Argentina) was destroyed by a catastrophic extraordinary flood in 1982-83. The main communities were Panicum prionitis tall grasslands. According to a succession model, they were seral communities that would have evolved to hygrophilous forest. After the flood, the area was surveyed in 1984, 1988 and 2002 and analyzed with numerical methods. First, the area was invaded by a community of annual species, which were the sparse species of tall grasslands, but five years after the colonization this community disappeared and was replaced by the original tall grasslands and turfs. The tall grasslands rapid recovery and the absence of woody species support the hypothesis that this community is a stable community which was rejuvenated by catastrophic floods and was prevented to develop into woody species communities.

Extraordinary Flood Response of a Small Urban Watershed to Short-Duration Convective Rainfall

Abstract 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.