Flood Series Research Articles

Flood frequency analysis based on simulated peak discharges

Flood frequency approaches vary from statistical methods, directly applied on the observed annual maximum flood series, to adopting rainfall–runoff simulation models that transform design rainfalls to flood discharges. Reliance on statistical flood frequency analysis depends on several factors such as the selected probability distribution function, estimation of the function parameters, possible outliers, and length of the observed flood series. Through adopting the simulation approach in this paper, watershed-average rainfalls of various occurrence probabilities were transformed into the corresponding peak discharges using a calibrated hydrological model. A Monte Carlo scheme was employed to consider the uncertainties involved in rainfall spatial patterns and antecedent soil moisture condition (AMC). For any given rainfall depth, realizations of rainfall spatial distribution and AMC conditions were entered as inputs to the model. Then, floods of different return periods were simulated by transforming rainfall to runoff. The approach was applied to Tangrah watershed in northeastern Iran. It was deduced that the spatial rainfall distribution and the AMCs exerted a varying influence on the peak discharge of different return periods. Comparing the results of the simulation approach with those of the statistical frequency analysis revealed that, for a given return period, flood quantiles based on the observed series were greater than the corresponding simulated discharges. It is also worthy to note that existence of outliers and the selection of the statistical distribution function has a major effect in increasing the differences between the results of the two approaches.

Hydrogeomorphic variability due to dam constructions and emerging problems: a case study of Damodar River, West Bengal, India

In the first multipurpose river valley planning of India, the vast resources of Damodar River Basin (DRB) (eastern India) are not only to be envisioned in their entirety but also to be developed in a unified manner where the water, land, and people are simultaneously bounded in a seamless web. Four large dams (Konar, Tilaiya, Maithon, and Panchet), Durgapur barrage, and Tenughat reservoir are built to tamp the flood-prone Damodar River using water resource in an integrated method. The functionality of Damodar fluvial system is controlled by dams, barrage, weirs, sluices, embankments, and canals, maintaining a dynamic equilibrium between fluvial processes and anthropogenic processes. Carrying more than 50 years of legacy, the existing drainage and flood control system of Damodar Valley Corporation has aggravated a number of hydrogeomorphic problems especially in lower DRB, viz. siltation of river bed and reservoirs, uncontrolled monsoonal stream flow, declining carrying capacity of lower course, drainage congestion, low-magnitude annual floods, channel shifting, de-functioned canals, decay of paleochannels, decline of ground water level, and less replenishing of soils with fresh silts. The present paper is mainly tried to investigate the pre-dam and post-dam hydrogeomorphic variability in relation to flood risk and drawbacks of Damodar Valley Multipurpose Project. Specifically, the annual peak flow of Damodar shifts from August to September due to dam construction and reservoir storage. Applying the annual flood series of log Pearson type III distribution, we have estimated post-dam 5-year peak discharge of above 5,300 m3 s−1 and 100-year flood of above 11,000 m3 s−1. Due to siltation, the bankfull discharges of sample segments are gradually declined up to 4,011 m3 s−1, 2,366 m3 s−1, and 1,542 m3 s−1, respectively, having recurrence interval of 1.18–3.18 years only. With the regulation of monsoon flow, the standard sinuosity index is gradually increased downstream, having high dominance of hydraulic factors in respect of topographic factors. The upstream section of study area (Rhondia to Paikpara) now shows the dominance of aggradational landforms, braiding, avulsion, high width–depth ratio, breaching of right bank, and valley widening, but downstream of Barsul the phenomena of bank erosion, confined sinuosity, low width–depth ratio, and narrowness are more pronounced.

Mapping spatio-temporal flood inundation dynamics at large river basin scale using time-series flow data and MODIS imagery

Flood inundation is crucial to the survival and prosperity of flora and fauna communities in floodplain and wetland ecosystems. This study tried to map flood inundation characteristics in the Murray-Darling Basin, Australia, utilizing hydrological and remotely sensed data. It integrated river flow time series and Moderate Resolution Imaging Spectroradiometer (MODIS) images to map inundation dynamics over the study area on both temporal and spatial dimensions. Flow data were analyzed to derive flow peaks and Annual Exceedance Probabilities (AEPs) using the annual flood series method. The peaks were linked with MODIS images for inundation detection. Ten annual maximum inundation maps were generated for water years 2001–2010, which were then overlaid to derive an inundation frequency map. AEPs were also combined with the annual maximum inundation maps to derive an inundation probability map. The resultant maps revealed spatial and temporal patterns of flood inundation in the basin, which will benefit ecological and environmental studies when considering response of floodplain and wetland ecosystems to flood inundation.

A generalized Grubbs‐Beck test statistic for detecting multiple potentially influential low outliers in flood series

The Grubbs‐Beck test is recommended by the federal guidelines for detection of low outliers in flood flow frequency computation in the United States. This paper presents a generalization of the Grubbs‐Beck test for normal data (similar to the Rosner (1983) test; see also Spencer and McCuen (1996)) that can provide a consistent standard for identifying multiple potentially influential low flows. In cases where low outliers have been identified, they can be represented as “less‐than” values, and a frequency distribution can be developed using censored‐data statistical techniques, such as the Expected Moments Algorithm. This approach can improve the fit of the right‐hand tail of a frequency distribution and provide protection from lack‐of‐fit due to unimportant but potentially influential low flows (PILFs) in a flood series, thus making the flood frequency analysis procedure more robust.

Assessment of Hydrologic Controls on Applicability of Routing Methods

Various applicability criteria have been developed to determine the appropriateness of different hydraulic routing methods (e.g., kinematic, diffusive, or dynamic) a priori (i.e., before any routing is done). However, little has been done to account for hydrologic variability and basin size in these criteria. To account for hydrologic variability and basin size in this paper, an existing applicability criteria for routing methods is linked analytically to a model of peak flow, a simple stochastic representation of rainfall, and relationships of river basin geomorphology. This linkage provides a novel way for understanding and quantifying the interrelationship between basin-scale hydrologic phenomena and routing methods. Using this linkage, the aim of this paper is to explore and assess the applicability of routing methods in strongly coupled systems or headwater basins. To illustrate and assess the linkage, the Illinois River basin is used. From this assessment, the diffusive and dynamic contributions are both found to increase for the general condition of an increasing peak flow and decreasing time to peak at a given basin size. After accounting for scale dependencies, the mean diffusive and dynamic contributions are found to increase with the basin size. The rate of increase seems controlled by the interplay between the slope-area relationship and the scaling of the time to peak, which in turn depends on both the mean rainfall duration and the time of concentration in this paper. In terms of the annual maximum flood series, the dynamic and diffusive contributions show decreasing and increasing trends, respectively, as a function of the basin size for a fixed return period. The latter is found to depend on the scaling of peak floods and the slope-area relationship. For a fixed basin size, both the diffusive and dynamic contributions are found to increase with the return period. The developed framework is able to provide insight at the basin scale into the influence of hydrologic controls arising from climate, runoff, and geomorphology on the applicability of routing methods.

Fish movement strategies in an ephemeral river in the Simpson Desert, Australia

AbstractArid zone catchments experience extreme hydrological variability and some rivers are entirely ephemeral, replenished only by intermittent flooding. The ecological roles of ephemeral systems are rarely studied. This paper describes movement patterns of fish in the Mulligan River, an ephemeral system in the Lake Eyre Basin, central Australia. Several sites were sampled along a temporal gradient encompassing floods and dry periods. After a single major flood in 2007 up to seven fish species were found at sites up to 300 km from the closest permanent waterhole. Following a series of floods (when waterholes were replenished and remained wet between 2009 and 2011) a further five species were recorded including the first records for the Lake Eyre hardyhead, Craterocephalus eyresii, from the rivers of far western Queensland. The presence of all species known from the parent catchment (the Georgina, where permanent waterholes occur) in the ephemeral catchment (the Mulligan) suggests that many fish species present in the river systems of central Australia are capable of dispersing long distances following the opening of movement pathways during flooding. However, two distinct groups of species were identified: extreme dispersing species, that move as far as possible into intermittently wetted habitats, and conservative dispersing species, that do not move as far, tending to inhabit deeper waterholes within mid‐reaches of the river that are more likely to hold water for longer. Preservation of the natural flow regime of Australia's arid‐zone rivers is important for maintaining these fish communities and facilitating study of their adaptations to ephemerality.

Flow characteristics and morphological changes in open-channel flows with alternate vegetation zones

In this study, turbulent flows and morphological changes in an open-channel that has alternate vegetated zones are numerically simulated by using a three-dimensional model. The Reynolds-averaged Navier-Stokes Equations are solved with the k-ɛ model. The simulated flow structures compared well with the measured data in the literature. Through numerical experiments, the evolution of the mean flow and turbulence structures for different vegetation densities is presented. The vegetation was found to curve the flow, and the meandering flow pattern becomes more definite with increasing vegetation density. When the channel morphological changes are simulated with a series of floods, the initial rectangular channel becomes a compound channel and the flow pattern changes from a straight stream to a meandering stream. The evolution of vegetation zones after the floods indicates that vegetation zones are expanded in the leeward of the initial vegetation zones, and that the size of the vegetation zone is increased about 2.5 times.

The chronology and the hydrometeorology of catastrophic floods on Dartmoor, South West England

AbstractExtreme floods are the most widespread and often the most fatal type of natural hazard experienced in Europe, particularly in upland and mountainous areas. These ‘flash flood’ type events are particularly dangerous because extreme rainfall totals in a short space of time can lead to very high flow velocities and little or no time for flood warning. Given the danger posed by extreme floods, there are concerns that catastrophic hydrometeorological events could become more frequent in a warming world. However, analysis of longer term flood frequency is often limited by the use of short instrumental flow records (last 30–40 years) that do not adequately cover alternating flood‐rich and flood‐poor periods over the last 2 to 3 centuries. In contrast, this research extends the upland flood series of South West England (Dartmoor) back to ca AD 1800 using lichenometry. Results show that the period 1820 to mid‐1940s was characterized by widespread flooding, with particularly large and frequent events in the mid‐to‐late 19th and early 20th centuries. Since ca 1850 to 1900, there has been a general decline in flood magnitude that was particularly marked after the 1930s/mid‐1940s. Local meteorological records show that: (1) historical flood‐rich periods on Dartmoor were associated with high annual, seasonal and daily rainfall totals in the last quarter of the 19th century and between 1910 and 1946, related to sub‐decadal variability of the North Atlantic Oscillation and receipt of cyclonic and southerly weather types over the southwest peninsula; and (2) the incidence of heavy daily rainfall declined notably after 1946, similar to sedimentary archives of flooding. The peak period of flooding on Dartmoor predates the beginning of gauged flow records, which has practical implications for understanding and managing flood risk on rivers that drain Dartmoor. Copyright © 2013 John Wiley & Sons, Ltd.

Transformation of a lowland river from a meandering and multi-channel pattern into an artificial canal: retracing a path of river channel changes (the Middle Obra River, W Poland)

At the beginning of the nineteenth century, a significant change in sedimentation took place along the middle course of the Obra River (W Poland): a “natural” channel bed was replaced by three artificial canals. Before that time the Obra River bed had been characterized by various river patterns (braided, meandering and disappearing in wetlands). GPR (ground-penetrating radar) surveys and the analysis of satellite and aerial images were carried out to retrace the natural river course near the village of Kopanica. The GPR, ground-truthed with core data, revealed that at least two types of the river pattern had been functioning here before the period of the hydrotechnical works: a large-scale meandering pattern (width-to-depth (w/d) ratio ranging from 15 to 40) and a relatively smaller-scale multi-channel pattern (w/d = 11–22). Possibly, the transformation was caused by forming a series of large floods followed by in-channel aggradation and avulsions. Next, the multi-channel pattern was artificially transformed into the North Obra Canal. This paper discusses possibilities of a creation of network of channels that were active after the construction of the North Obra Canal in the beginning of the nineteenth century. Such intervention would increase natural values of the presented section of the Obra valley. The presented study also shows that a detailed analysis of history and evolution of a given river course is needed before undertaking any restoration works.

Dynamical Structure of Extreme Floods in the U.S. Midwest and the United Kingdom

AbstractTwenty extreme spring floods that occurred in the Ohio basin between 1901 and 2008, identified from daily river discharge data, are investigated and compared to the April 2011 Ohio River flood event. Composites of synoptic fields for the flood events show that all of these floods are associated with a similar pattern of sustained advection of low-level moisture and warm air from the tropical Atlantic Ocean and the Gulf of Mexico. The typical flow conditions are governed by an anomalous semistationary ridge, situated east of the U.S. East Coast, that steers the moisture and converges it into the Ohio River valley. Significantly, the moisture path common to all of the 20 cases studied here as well as the case of April 2011 is distinctly different from the normal path of Atlantic moisture during spring, which occurs farther west. It is shown further that the Ohio basin moisture convergence responsible for the floods is caused primarily by the atmospheric circulation anomaly advecting the climatological mean moisture field. Transport and related convergence due to the covariance between moisture anomalies and circulation anomalies are of secondary but nonnegligible importance. The importance of atmospheric circulation anomalies to floods is confirmed by conducting a similar analysis for a series of winter floods on the river Eden in northwest England.

Flooding in Texas: Examination of Temporal Changes and Impacts of Tropical Cyclones

AbstractAnnual maximum peak discharge measurements from 62 stations with a record of at least 70 years are used to assess extreme flooding in Texas at the regional scale. This work focuses on examination of the validity of the stationarity assumption and on the impact of tropical cyclones (TCs) on the upper tail of the flood peak distribution. We assess the validity of the stationarity assumption by testing the records for abrupt and gradual changes. The presence of abrupt changes in the first two moments of the flood peak distribution is assessed using the Lombard test. We use the Mann‐Kendall test to examine the presence of monotonic trends. Results indicate that violations of the stationarity assumption are most commonly caused by abrupt changes, which are often associated with river regulation. We fit the time series of stationary flood records with the generalized extreme value distribution to investigate whether TCs control the upper tail of the flood peak distribution. Our results indicate that TCs play a diminished role in shaping the upper tail of the flood peak distribution compared with areas of the eastern United States subject to frequent TCs.

An analysis of extreme flood events during the past 400 years at Taihu Lake, China

Summary Considerable attention has been paid to the extreme floods affecting Taihu Lake and the lower reaches of the Yangtze River (China) since they have caused serious socio-economic problems past and present. To fully understand these low probability events, it is necessary to build longtime-series of flood occurrence using flood-level proxies from archaeology and sedimentology that extends the period of observation beyond that of instrumental data. Using historical stele flood markers relicts and lacustrine sediment records from Taihu Lake, this paper attempts to reconstruct the historical flood events, to compare the stele-measured flood levels with those recorded by the modern gauges, and to identify the extreme flood signals among the flood events over the past 400 years. Results indicate that the lowest lake level of the 15 extreme floods by stele-records in the period 1600–1954 AD was 4.07 m a.s.l., equivalent to the 80th percentile of hydrological-gauged lake levels during 1921–2004 AD; this comparison provides a quantitative analogue for the floods reconstructed from lake sediments. Flood signals from coarse silt–sand sediments and low-frequency magnetic susceptibility profiles captured 85% of flood years in the historical period, and five extreme flood years that were missed in the stele flood records were found. There were three flood years that were identified from the historical documents in 1766, 1875 and 1882 AD, respectively, when lake-flood levels were estimated at 4.0–4.1 m, 4.1–4.2 m and 4.13–4.23 m, respectively. Spectral analysis was used to identify return periods from the three time series of the stele flood records, grain flood index and magnetic flood index, respectively; these analyses indicated some synchronous patterns and showed common return periods of 90–102 years, 60–62 years and 42–44 years. To test if the historical extreme floods have statistical relationships with climate variability, a two-variables-conditional test following Poisson’s distribution was applied: the estimated probabilities of 0.17–0.20 between a proxy of the Pacific Decadal Osculation (PDO) and the flood events were obtained. These estimates indicate that the hypothesis that the two variables have significant correlations can be accepted, suggesting that the Taihu historical extreme floods were significantly linked with the changes in the Pacific monsoon and summer precipitation. This study demonstrate the possibility of reconstructing past extreme floods where gauge data are not available and has relevance to the prediction of future extreme floods which will have possible disastrous socio-economic impacts on the Taihu catchment.

Flood Mapping and Flood Dynamics of the Mekong Delta: ENVISAT-ASAR-WSM Based Time Series Analyses

Satellite remote sensing is a valuable tool for monitoring flooding. Microwave sensors are especially appropriate instruments, as they allow the differentiation of inundated from non-inundated areas, regardless of levels of solar illumination or frequency of cloud cover in regions experiencing substantial rainy seasons. In the current study we present the longest synthetic aperture radar-based time series of flood and inundation information derived for the Mekong Delta that has been analyzed for this region so far. We employed overall 60 Envisat ASAR Wide Swath Mode data sets at a spatial resolution of 150 meters acquired during the years 2007–2011 to facilitate a thorough understanding of the flood regime in the Mekong Delta. The Mekong Delta in southern Vietnam comprises 13 provinces and is home to 18 million inhabitants. Extreme dry seasons from late December to May and wet seasons from June to December characterize people’s rural life. In this study, we show which areas of the delta are frequently affected by floods and which regions remain dry all year round. Furthermore, we present which areas are flooded at which frequency and elucidate the patterns of flood progression over the course of the rainy season. In this context, we also examine the impact of dykes on floodwater emergence and assess the relationship between retrieved flood occurrence patterns and land use. In addition, the advantages and shortcomings of ENVISAT ASAR-WSM based flood mapping are discussed. The results contribute to a comprehensive understanding of Mekong Delta flood dynamics in an environment where the flow regime is influenced by the Mekong River, overland water-flow, anthropogenic floodwater control, as well as the tides.

Sedimentological and hydrological studies of the palaeoflood events in the Ankang east section in the upper reaches of the Hanjiang River

通过沿汉江上游河谷深入的考察,在安康东段发现了典型的古洪水滞流沉积剖面.通过采集样品、实验分析,确定它们是古洪水在高水位滞流环境当中的悬移质沉积物.根据地层对比、OSL测年和相关文化层年代,确定它们分别记录了发生在BL+AL与YD事件转折阶段(12500 a B.P.)的古洪水事件和发生在1000-900 a B.P.(1000-1100AD),即北宋后期的洪水事件.根据古洪水SWD的高程恢复其洪峰水位,结合相关参数,利用面积比降法计算恢复流量.结果表明在万年尺度,汉江上游古洪水洪峰流量介于35970~47400 m³/s之间.同时,利用2010年大洪水洪痕恢复计算洪峰流量,对古洪水洪峰流量计算结果进行了验证.进而结合历史洪水和观测洪水数据,获得了汉江上游万年尺度洪水洪峰流量与频率关系.这为汉江上游的水利水电和交通工程建设以及沿岸城镇防洪减灾提供了基础性数据.;Through field investigation in the upper reaches of the Hanjiang River,palaeoflood slackwater deposits were found in the Ankang east section.The results of sedimentary analyses indicate that these slackwater deposits are typical suspended sediment load deposits of floodwater.By stratigraphic correlation,OSL dating and archaeological dating,the palaeoflood events represented by SWD1 were dated to be between the palaeo-climatic stage of BL+AL and Younger Dryas Event (YD,12500 a B.P.).During this period,the upper reaches of the Hanjiang River experienced a series of rainstorm flood events.The pollen records from the Southern Lake of Shennongjia area in the upper reaches of the Hanjiang River also suggest that this was the period of high climatic fluctuation frequency.The SWD2 in the east Ankang section appears in the bottom of well-developed modern topsoil layer.At the edges of Ankang-Yunxian river terrace,the set of SWD layers often cover the culture layer which belongs the Northern Song Dynasty when climate condition was very unstable,and serious drought and flood disaster occurred based upon historical records.The palaeoflood events recorded by SWD2 were dated to be AD 1000-1100 (i.e.1000-1100 a).Based on the reconstruction of palaeoflood peak stages and the hydrological parameters for the river section,the palaeoflood peak discharges were between 35970 and 47400 m³/s.These values were checked with the the reconstruction of the flood in 2010 based on the stage indicator identified during the fieldwork,and the results showed the Ankang hydrologic station measured data error is only 4.52%.Thus we believe that the peak flow calculation for the upper reaches of the Hanjiang River canyon ancient flood is reasonably accurate,the calculation results are reliable.Based on our calculation from sedimentological perspective the historical flood investigation results were combined with observed flood series,with a large value of the complete sequence of frequency calculation method,and the upper reaches of Hanjiang River in the eastern part of Ankang section million-years-scale peak flow and frequency relations were established.The results provide data for establishing flood discharge-frequency relationship at a 10000-year time-scale in the upper reaches of the Hanjiang River.This is very critic and will provides key data for hydraulic engineering and flood control in the upper reaches of the Hanjiang River and the flood control and disaster mitigation engineering construction along the waterfront towns in the region,except the scientific value of the Hanjiang River's regional changes in climate and hydrology in response to the global climate changes.

Hydrological Design of Nonstationary Flood Extremes and Durations in Wujiang River, South China: Changing Properties, Causes, and Impacts

The flood-duration-frequency (QDF) analysis is performed using annual maximum streamflow series of 1–10 day durations observed at Pingshi and Lishi stations in southern China. The trends and change point of annual maximum flood flow and flood duration are also investigated by statistical tests. The results indicate that (1) the annual maximum flood flow only has a marginally increasing trend, whereas the flood duration exhibits a significant decreasing trend at the 0.10 significant level. The change point for the annual maximum flood flow series was found in 1991 and after which the mean maximum flood flow increased by 45.26%. (2) The period after 1991 is characterized by frequent and shorter duration floods due to increased rainstorm. However, land use change in the basin was found intensifying the increased tendency of annual maximum flow after 1991. And (3) under nonstationary environmental conditions, alternative definitions of return period should be adapted. The impacts on curve fitting of flood series showed an overall change of upper tail from “gentle” to “steep,” and the design flood magnitude became larger. Therefore, a nonstationary frequency analysis taking account of change point in the data series is highly recommended for future studies.

Analysis of the Marmara flood in Turkey, 7–10 September 2009: an assessment from hydrometeorological perspective

Turkey often suffers from flood-related damages and causalities as a result of intense and prolonged storms that are usually convective or cyclonic in origin. The impact is more distinctive in Aegean and Mediterranean coasts of the country where quantity and distribution of rainfall is influenced by Mediterranean cyclones, especially in late autumn and early winter. The floods sometimes became very hazardous when combined with urbanization effects, especially in the densely populated coastal communities and major cities. Severe weather was marked in the early parts of September 2009 that produced record-setting rainfall amounts across the Marmara region of Turkey and led a series of flash floods which affected Istanbul and Tekirdag provinces especially. The overall flooding was the result of successive and persistent intense rainfall episodes over a 3-day period which produced more than 250-mm rainfall over portions of the region. The floods resulted in death of 32 people and caused extensive environmental and infrastructural damage in the region. This study provides in-depth analysis of hydrometeorological conditions that led to the occurrence of flash floods in Marmara region during 7–10 September 2009 period and also discusses non-meteorological factors that exacerbated the flooding conditions. Main meteorological settings that led to intense storms were presence of cold air in the upper atmosphere, a slow-moving quasi-stationary trough, and continuous resupply of moisture to the surface low from the warm Aegean Sea. Radar images showed the development of clusters of convective cells that remained quasi-stationary over portions of the region. The 24-h rainfall amounts varied between 100 and 253 mm in most parts of the region during the flooding period with diverse spatial patterns. The southern locations received the highest amount of the rainfall as compared to stations located in northern slopes of the region. Typical effects of orography that enhance rainfall in the coastal areas, however, were not observed during the Marmara flood. Some features of the synoptic pattern observed prior and during the flooding period, supported the back door cold front concept. This is characterized with easterly to northeasterly surface flows forced by an anticyclone, advection of cold continental air over the warm Black Sea which provided anomalous moisture to trigger cyclogenesis over the Marmara region, and falling of core of the intense rainfall over the Marmara Sea. The study concluded that although the meteorological settings were favorable for the convective rainfalls, urbanization factors, such as land use changes and occupation of flood plains, played major role in aggravating the worst flood observed in the region in recent decades.

Spatial Dynamics and Growth of Two Native Species of Catostomids: are Movements Restricted?

Abstract We investigated movement and growth of two common suckers, Catostomus clarki and Catostomus insignis, in three streams that represent the broad environmental tolerances of these species. There was limited evidence of restricted movement in C. clarki, with many individuals moving 600 m and 50–90% of recaptured individuals detected outside the original location of capture. Catostomus insignis was more sedentary than C. clarki with only 25% recaptured outside of the original location of capture. Movement patterns of the two species also varied among streams, with C. clarki moving further in Sonoita Creek than Bonita Creek or West Fork Black River, Arizona. Sonoita Creek experienced a series of floods and while movements after flooding were predominately downstream, rates of recapture were similar to those during pre-flood sampling. Rates of growth and body condition also varied among streams.

Comprehensive Diagnosis of Kuyehe Flood Series Change-Point

The comprehensive diagnosis method can avoid the unreasonable of single analysis method and inconsistency of various analysis methods. This paper used the method to diagnosis the change-point of Kuyehe flood series. The result is consistent with the hydrological investigated results, which can provide the basis of quantifying the impact of changes of underlying surface conditions on the watershed runoff.

Gender and building homes in disaster in Sindh, Pakistan

During 2010 and 2011, Pakistan experienced a series of catastrophic floods. Sindh was the worst affected province, where people already living with chronic poverty and accompanying vulnerability were still recovering from the 2010 mega floods. Women, elderly people, minority groups, differently abled people, and children were among those hit hardest. This study examines and evaluates the gender aspects of the early recovery housing/one–two-room shelters provided by humanitarian organisations to replace destroyed houses in two districts (Dadu and Thatta) of Sindh Province. It draws on examples from the field in order to understand the experiences of vulnerable people, especially women, in participating in housing programmes and projects. Results show that international and national standards related to gender were not, in this case, properly taken up in the implementation of the response.

The Thames flood series: a lack of trend in flood magnitude and a decline in maximum levels

The flow series for the River Thames near its tidal limit is one of the most studied in the world. Its length and completeness, and the richness of the historical information which augments the formal flow record, ensures that the series is of immense value. However, the variability in flood magnitude and frequency that it captures needs to be interpreted with caution. The homogeneity of the time series is influenced by a wide range of factors, including changes in the hydrometric capability of the gauging station and the impact of differing water, river and land management practices on the flow regime. Nevertheless, both the daily flow series and the record of lock levels provide some reassuring signals regarding the resilience of the Thames to fluvial flood risk in a warming world. Since routine flow measurement began in 1883, the Thames basin has seen a substantial rise in air temperature and a tendency for both winter rainfall and annual runoff to increase. There is no trend in fluvial flood magnitude however, partly reflecting a decline in snowmelt contributions to major floods and annual maximum lock levels show a significant decline, reflecting a highly sustained programme of river management.