scholarly journals Response of flood events to extreme precipitation: two case studies in Taihu Basin, China

2021 ◽  
Author(s):  
Feiqing Jiang ◽  
Zengchuan Dong ◽  
Yun Luo ◽  
Moyang Liu ◽  
Tao Zhou ◽  
...  
Keyword(s):  
Flood Risk ◽  
Extreme Precipitation ◽  
Flood Control ◽  
Return Periods ◽  
Flood Events ◽  
Copula Functions ◽  
Taihu Basin ◽  
Extreme Flood ◽  
Genetic Mechanisms ◽  
Precipitation Events

Abstract Flood events are typically triggered by extreme precipitation in rain-dominant basins. In this study, to better understand the genetic mechanisms and characteristics of floods, copula functions are used to analyze the response of flood events to extreme precipitation. The coincidence probabilities of the typical extreme flood and precipitation events are calculated; different return periods of their arbitrary combinations are calculated, whereas the dangerous domains for flood control under different return periods are identified; furthermore, flood risk analysis under different extreme precipitation scenarios is performed via their conditional exceedance probabilities. The Xitiaoxi catchment (XC) and Dongtiaoxi catchment (DC) in the Zhexi Region of the Taihu Basin are selected as the study area. The results show that in four scenarios with precipitation frequencies of 80%, 90%, 93.33%, and 95%, the probabilities of the dangerous flood are 9.72%, 10.57%, 10.86%, and 11.01% in the XC, respectively, and 5.91%, 6.31%, 6.44%, and 6.51% in the DC, respectively. This study provides a practical basis and guidance for the computation of rainstorm designs, management of flood control safety, and water resource scheduling in the Taihu Basin.

scholarly journals Quantitative Agricultural Flood Risk Assessment Using Vulnerability Surface and Copula Functions

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1229 ◽  
Author(s):  
Yongfang Wang ◽  
Guixiang Liu ◽  
Enliang Guo ◽  
Xiangjun Yun
Keyword(s):  
Flood Risk ◽  
Extreme Precipitation ◽  
Joint Distribution ◽  
Disaster Risk ◽  
Flood Disaster ◽  
Surface Model ◽  
Copula Functions ◽  
Extreme Precipitation Events ◽  
Flood Disasters ◽  
Precipitation Events

Agricultural flood disaster risk assessment plays a vital role in agricultural flood disaster risk management. Extreme precipitation events are the main causes of flood disasters in the Midwest Jilin province (MJP). Therefore, it is important to analyse the characteristics of extreme precipitation events and assess the flood risk. In this study, the Multifractal Detrended Fluctuation Analysis (MF-DFA) method was used to determine the threshold of extreme precipitation events. The total duration of extreme precipitation and the total extreme precipitation were selected as flood indicators. The copula functions were then used to determine the joint distribution to calculate the bivariate joint return period, which is the flood hazard. Historical data and flood indicators were used to build an agricultural flood disaster vulnerability surface model. Finally, the risk curve for agricultural flood disasters was established to assess the flood risk in the MJP. The results show that the proposed approaches precisely describe the joint distribution of the flood indicators. The results of the vulnerability surface model are in accordance with the spatiotemporal distribution pattern of the agricultural flood disaster loss in this area. The agricultural flood risk of the MJP gradually decreases from east to west. The results provide a firm scientific basis for flood control and drainage plans in the area.

scholarly journals Brief Communication: Critical Infrastructure impacts of the 2021 mid-July western European flood event

2021 ◽  
Author(s):  
Elco Koks ◽  
Kees Van Ginkel ◽  
Margreet Van Marle ◽  
Anne Lemnitzer
Keyword(s):  
The Netherlands ◽  
Flood Risk ◽  
Extreme Precipitation ◽  
Large Scale ◽  
Critical Infrastructure ◽  
Risk Assessments ◽  
Flood Events ◽  
Infrastructure Systems ◽  
River Flood ◽  
Sewage Systems

Abstract. Germany, Belgium and The Netherlands were hit by extreme precipitation and flooding in July 2021. This Brief Communication provides an overview of the impacts to large-scale critical infrastructure systems and how recovery has progressed during the first six months after the event. The results show that Germany and Belgium were particularly affected, with many infrastructure assets severely damaged or completely destroyed. Impacts range from completely destroyed bridges and sewage systems, to severely damaged schools and hospitals. We find that large-scale risk assessments, often focused on larger (river) flood events, do not find these local, but severe, impacts. This may be the result of limited availability of validation material. As such, this study will not only help to better understand how critical infrastructure can be affected by flooding, but can also be used as validation material for future flood risk assessments.

scholarly journals Ocupación de la llanura aluvial e inundaciones en el Pirineo Central

2017 ◽  
Vol 43 (1) ◽  
pp. 309 ◽  
Author(s):  
R. Serrano-Notivoli ◽  
D. Mora ◽  
A. Ollero ◽  
M. Sánchez-Fabre ◽  
P. Sanz ◽  
...  
Keyword(s):  
Land Use ◽  
Urban Areas ◽  
Return Periods ◽  
Flood Events ◽  
Mountain Regions ◽  
Human Occupation ◽  
The Past ◽  
Precipitation Characteristics ◽  
Natural Dynamics ◽  
Precipitation Events

Floods modify the natural dynamics of river environments and greatly affect urban areas, especially in mountain regions where flooding is frequent because of the precipitation characteristics and orographic configuration. In this study the vulnerability of the central sector of the Pyrenees to flood events was investigated using frequency analysis of daily flow and precipitation data for the period from 1940 to 2012 for the headwaters of the Aragón and Ésera rivers. The land use evolution over the past 60 years was also analyzed. The return periods showed that floods have not been exceptional, and the high flow frequency has been large and closely related to precipitation events. This, combined with a large increase in human occupation, particularly since the 1990s, of fluvial areas associated with the land use evolution since 1956, has increased exposure to flood risks.

scholarly journals Sensitivity of Heavy Precipitation Forecasts to Small Modifications of Large-Scale Weather Patterns for the Elbe River

2010 ◽  
Vol 11 (3) ◽  
pp. 770-780 ◽  
Author(s):  
Ingo Schlüter ◽  
Gerd Schädler
Keyword(s):  
Extreme Precipitation ◽  
Large Scale ◽  
Spatiotemporal Variability ◽  
Small Scale ◽  
Synoptic Situation ◽  
Flood Events ◽  
Weather Patterns ◽  
Extreme Precipitation Events ◽  
The Impact ◽  
Precipitation Events

Abstract Extreme flood events are caused by long-lasting and/or intensive precipitation. The detailed knowledge of the distribution, intensity, and spatiotemporal variability of precipitation is, therefore, a prerequisite for hydrological flood modeling and flood risk management. For hydrological modeling, temporal and spatial high-resolution precipitation data can be provided by meteorological models. This study deals with the question of how small changes in the synoptic situation affect the characteristics of extreme forecasts. For that purpose, two historic extreme precipitation events were hindcasted using the Consortium for Small Scale Modeling (COSMO) model of the German Weather Service (DWD) with different grid resolutions (28, 7, and 2.8 km), where the domains with finer resolutions were nested into the ones with coarser resolution. The results show that the model is capable of simulating such extreme precipitation events in a satisfactory way. To assess the impact of small changes in the synoptic situations on extreme precipitation events, the large-scale atmospheric fields were shifted to north, south, east, and west with respect to the orography by about 28 and 56 km, respectively, in one series of runs while in another series, the relative humidity and temperature were increased to modify the amount of precipitable water. Both series were performed for the Elbe flood events in August 2002 and January 2003, corresponding to two very different synoptic situations. The results show that the modeled precipitation can be quite sensitive to small changes of the synoptic situation with changes in the order of 20% for the maximum daily precipitation and that the types of synoptic situations play an important role. While van Bebber weather conditions, of Mediterranean origin, were quite sensitive to modifications, more homogeneous weather patterns were less sensitive.

scholarly journals Flood Risk Evaluation in Urban Spaces: The Study Case of Tormes River (Salamanca, Spain)

2018 ◽  
Vol 16 (1) ◽  
pp. 5 ◽  
Author(s):  
Marco Criado ◽  
Antonio Martínez-Graña ◽  
Javier San Román ◽  
Fernando Santos-Francés
Keyword(s):  
Flood Risk ◽  
Risk Evaluation ◽  
Urban Spaces ◽  
Return Periods ◽  
Hazard Maps ◽  
Flood Events ◽  
Hazard Exposure ◽  
Preventive Actions ◽  
Study Case ◽  
Different Levels

The expansion of cities towards flood zones, and the increasingly frequent episodes of torrential rains arising from global warming, mean that the population is becoming more exposed to floods. Due to this, a correct assessment of flood events is of great help in the development of preventive actions, planning and resource management, or interventions. For this reason, in this work we aim to establish guidelines to assess the hazard, exposure, and vulnerability of the population and its properties to flood events, using Hec-Ras for the simulation of the flood and ArcGis and GeoHecRas to treat geographic information and prepare the cartography. The study was focused on the Tormes River in Salamanca (Spain). We studied three return periods with different probabilities of occurrence and intensity, corresponding to 5, 100, and 500 years. The flow corresponding to each episode was calculated, along with the extension, speed, and depth that would be achieved in each case. Then, the probability of occurrence was delimited, as well as the magnitude, allowing us to obtain different hazard maps. In addition, the areas of greatest hazard to people and property were established for each event. Regarding the exposure, the areas and land use, infrastructure, and buildings that would be flooded in each case were identified, quantifying the extension or length of the affected properties at the different levels of hazard in each case. Additionally, the vulnerability of the different buildings and exposed infrastructure was studied. Finally, the flood risk was estimated by combining these three components.

scholarly journals Spatiotemporal variation characteristics of extreme precipitation in the upper reaches of the Hongshui River Basin during 1959–2016

2021 ◽  
Author(s):  
Ya Huang ◽  
Ling Yi ◽  
Weihua Xiao ◽  
Guibing Hou ◽  
Yuyan Zhou
Keyword(s):  
River Basin ◽  
Extreme Precipitation ◽  
Water Resource Management ◽  
Flood Control ◽  
Southern Oscillation ◽  
Disaster Mitigation ◽  
Eastern Region ◽  
Extreme Precipitation Indices ◽  
Precipitation Indices ◽  
Precipitation Events

Abstract Understanding changes in the intensity and frequency of extreme precipitation is vital for flood control, disaster mitigation, and water resource management. In this study, 12 extreme precipitation indices and the best-fitting extreme value distribution were used to analyze the spatiotemporal characteristics of extreme precipitation in the upper reaches of the Hongshui River Basin (UHRB). The possible links between extreme precipitation and large-scale circulation were also investigated. Most extreme precipitation indices increased from west to east in the UHRB, indicating that the eastern region is a humid area with abundant precipitation. The indices for consecutive wet days (CWD) and precipitation events (R0.1) decreased significantly, indicating that the UHRB tends to be dry, with few precipitation events. The probability distribution functions of most extreme precipitation indices, especially that of R0.1, shifted significantly to the left in 1988–2016 compared with 1959–1987, further indicating that the UHRB has experienced a significant drying trend in recent decades. The East Asian summer monsoon and the El Niño–Southern Oscillation/Pacific Decadal Oscillation were confirmed to influence extreme precipitation in the UHRB. These findings are helpful for understanding extreme precipitation variation trends in the UHRB and provide references for further research.

scholarly journals Extensive spatio-temporal assessment of flood events by application of pair-copulas

2015 ◽  
Vol 370 ◽  
pp. 177-181 ◽  
Author(s):  
M. Schulte ◽  
A. H. Schumann
Keyword(s):  
River Basin ◽  
Flood Risk ◽  
Dependence Structure ◽  
Flood Events ◽  
Multivariate Statistical ◽  
Local Conditions ◽  
Extreme Flood ◽  
Multivariate Statistical Approach ◽  
Spatio Temporal ◽  
Peak Discharges

Abstract. Although the consequences of floods are strongly related to their peak discharges, a statistical classification of flood events that only depends on these peaks may not be sufficient for flood risk assessments. In many cases, the flood risk depends on a number of event characteristics. In case of an extreme flood, the whole river basin may be affected instead of a single watershed, and there will be superposition of peak discharges from adjoining catchments. These peaks differ in size and timing according to the spatial distribution of precipitation and watershed-specific processes of flood formation. Thus, the spatial characteristics of flood events should be considered as stochastic processes. Hence, there is a need for a multivariate statistical approach that represents the spatial interdependencies between floods from different watersheds and their coincidences. This paper addresses the question how these spatial interdependencies can be quantified. Each flood event is not only assessed with regard to its local conditions but also according to its spatio-temporal pattern within the river basin. In this paper we characterise the coincidence of floods by trivariate Joe-copula and pair-copulas. Their ability to link the marginal distributions of the variates while maintaining their dependence structure characterizes them as an adequate method. The results indicate that the trivariate copula model is able to represent the multivariate probabilities of the occurrence of simultaneous flood peaks well. It is suggested that the approach of this paper is very useful for the risk-based design of retention basins as it accounts for the complex spatio-temporal interactions of floods.

scholarly journals More frequent flash flood events and extreme precipitation favouring atmospheric conditions in temperate regions of Europe

2021 ◽  
Author(s):  
Judith Meyer ◽  
Malte Neuper ◽  
Luca Mathias ◽  
Erwin Zehe ◽  
Laurent Pfister
Keyword(s):  
Extreme Precipitation ◽  
Western Europe ◽  
Flash Flood ◽  
Flash Floods ◽  
Water Levels ◽  
Specific Humidity ◽  
Atmospheric Conditions ◽  
Flood Events ◽  
Extreme Precipitation Events ◽  
Precipitation Events

Abstract. In recent years, flash floods repeatedly occurred in temperate regions of central western Europe. Unlike in Mediterranean catchments, this flooding behaviour is unusual. In the past, and especially in the 1990s, floods were characterized by predictable, slowly rising water levels during winter and driven by westerly atmospheric fluxes (Pfister et al., 2004). The intention of this study is to link the recent occurrence of flash floods in central western Europe to extreme precipitation and specific atmospheric conditions to identify the cause for this apparent shift. Therefore, we hypothesise that an increase in extreme precipitation events has subsequently led to an increase in the occurrence of flash flood events in central western Europe and all that being caused by a change in the occurrence of flash flood favouring atmospheric conditions. To test this hypothesis, we compiled data on flash floods in central western Europe and selected precipitation events above 40 mm h−1 from radar data (RADOLAN, DWD). Moreover, we identified proxy parameters representative for flash flood favouring atmospheric conditions from the ERA5 reanalysis dataset. High specific humidity in the lower troposphere (q ≥ 0.004 kg kg−1), sufficient latent instability (CAPE ≥ 100 J kg−1) and weak deep-layer wind shear (DLS ≤ 10 m s−1) proved to be characteristic for long-lasting intense rainfall that can potentially trigger flash floods. These atmospheric parameters, as well as the flash flood and precipitation events were then analysed using linear models. Thereby we found significant increases in atmospheric moisture contents and increases in atmospheric instability. Parameters representing the motion and organisation of convective systems occurred slightly more often or remained unchanged in the time period from 1981–2020. Moreover, a trend in the occurrence of flash floods was confirmed. The number of precipitation events, their maximum 5-minute intensities as well as their hourly sums were however characterized by large inter-annual variations and no trends could be identified between 2002–2020. This study therefore shows that the link from atmospheric conditions via precipitation to flash floods cannot be traced down in an isolated way. The complexity of interactions is likely higher and future analyses should include other potentially relevant factors such as intra-annual precipitation patterns or catchment specific parameters.

scholarly journals Evaluation of precipitation extremes and floods and comparison between their temporal distributions

2015 ◽  
Vol 12 (1) ◽  
pp. 281-310 ◽  
Author(s):  
M. Müller ◽  
M. Kašpar ◽  
A. Valeriánová ◽  
L. Crhová ◽  
E. Holtanová
Keyword(s):  
Precipitation Extremes ◽  
Precipitation Data ◽  
Hydrological Response ◽  
Spatial Averaging ◽  
Flood Events ◽  
The Czech Republic ◽  
Extreme Precipitation Events ◽  
Extreme Flood ◽  
Abnormality Index ◽  
Precipitation Events

Abstract. We proposed three analogous extremity indices based on the estimated return periods at individual sites and spatial averaging of the values; we optimized both the areal extent and the duration of individual events. The weather extremity index (WEI), the weather abnormality index (WAI), and the flood extremity index (FEI) were applied to the original precipitation data, the seasonally transformed precipitation data, and the runoff data to identify extreme precipitation events (EPEs), abnormal precipitation events (APEs), and extreme flood events (EFEs), respectively. We present 50 events of each type from the period of 1961–2010 in the Czech Republic and compare their inter-annual and seasonal distributions. Most of EFEs were produced by an EPE in warmer half-years, whereas fewer than half of the EFEs were produced by an APE in the remainders of the years because thawing can substantially enhance the discharge at those times. Most significant EPEs occurred in July and the first half of August, although their hydrological responses were also significantly influenced by the antecedent saturation and other factors. As a result, the accumulation of precipitation extremes during the 1977–1986 period produced less significant flooding than another accumulation after 1996. In general, the primary discrepancies between the magnitudes of EPEs and EFEs occurred in May and September, when consequent floods were usually much larger and smaller in relation to the WEI, respectively. The hydrological response to APEs was usually strong in December, whereas another accumulation of EFEs in March was usually not due to APEs. Neither precipitation nor flood extremes occurred from early April through early May. This study confirms that variations in the frequency and/or magnitude of floods can be due not only to variations in the magnitude of precipitation events but also to variations in their seasonal distribution and other factors, primarily the antecedent saturation. The differences could be further studied with respect to circulation conditions.

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