scholarly journals Analysis of Flood Risk of Urban Agglomeration Polders Using Multivariate Copula

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1470 ◽  
Author(s):  
Yuqin Gao ◽  
Dongdong Wang ◽  
Zhenxing Zhang ◽  
Zhenzhen Ma ◽  
Zichen Guo ◽  
...  

Urban agglomeration polders (UAPs) are often used to control flooding in eastern China. The impacts of UAPs on individual flood events have been extensively examined, but how flood risks are influenced by UAPs is much less examined. This study aimed to explore a three-dimensional joint distribution of annual flood volume, peak flow and water level to examine UAPs’ impact on flood risks based on hydrological simulations. The dependence between pairwise hydrological characteristics are measured by rank correlation coefficients and graphs. An Archimedean Copula is applied to model the dependence structure. This approach is applied to the Qinhuai River Basin where UAPs are used proactively for flood control. The result shows that the Frank Copula can better represent the dependence structure in the Qinhuai River Basin. UAPs increase risks of individual flood characteristics and integrated risks. UAPs have a relatively greater impact on water level than the other two flood characteristics. It is noted that the impact on flood risk levels off for greater floods.

2017 ◽  
Vol 75 (9) ◽  
pp. 2130-2138 ◽  
Author(s):  
Yuqin Gao ◽  
Yu Yuan ◽  
Huaizhi Wang ◽  
Arthur R. Schmidt ◽  
Kexuan Wang ◽  
...  

The urban agglomeration polders type of flood control pattern is a general flood control pattern in the eastern plain area and some of the secondary river basins in China. A HEC-HMS model of Qinhuai River basin based on the flood control pattern was established for simulating basin runoff, examining the impact of urban agglomeration polders on flood events, and estimating the effects of urbanization on hydrological processes of the urban agglomeration polders in Qinhuai River basin. The results indicate that the urban agglomeration polders could increase the peak flow and flood volume. The smaller the scale of the flood, the more significant the influence of the polder was to the flood volume. The distribution of the city circle polder has no obvious impact on the flood volume, but has effect on the peak flow. The closer the polder is to basin output, the smaller the influence it has on peak flows. As the level of urbanization gradually improving of city circle polder, flood volumes and peak flows gradually increase compared to those with the current level of urbanization (the impervious rate was 20%). The potential change in flood volume and peak flow with increasing impervious rate shows a linear relationship.


2018 ◽  
Vol 28 (2) ◽  
pp. 68-75
Author(s):  
Magda Hudak ◽  
Urszula Kołodziejczyk ◽  
Jakub Kostecki ◽  
Ireneusz Nowogoński ◽  
Marta Żebrowska

Abstract This paper presents the impact of rainfall on the degree of flood risk in the basin of the middle Bobr River in western Poland. When the average rainfall level reaches 15 to 20 mm, this apparently calm river may dramatically change its character within just one week. The most important flood risks are flood waves in the headwaters. Because of the mountain character of the river basin, during intensive rainfall there is a huge surface runoff and the water level rises rapidly in the river. This phenomenon was observed in June 2017 in the town of Zagan (Lubuskie Voivodeship). It has been shown that the course and dynamics of hydrological processes occurring in the Bobr River basin depend on its physical and geographical characteristics and the influence of anthropogenic factors. The location is one of the main cause of numerous floods for Zagan, on the other hand changes in land development plays significant meaning in flood hazards. Continuous monitoring of the river is the basis for a comprehensive forecast of flood risks.


2018 ◽  
Vol 18 (5) ◽  
pp. 1852-1860 ◽  
Author(s):  
Yuqin Gao ◽  
Yu Yuan ◽  
Huaizhi Wang ◽  
Zhenxing Zhang ◽  
Liu Ye

Abstract Flood control with polders is prevalent in East China. Their impact on flood processes is critically important for flood control, but has not been well documented. The Qinhuai River Basin was selected as the study area. A Hydrologic Engineering Center – River Analysis System (HEC-RAS) hydraulic model was developed to simulate and predict storm flood processes and the associated impact of polders. The study shows that the HEC-RAS model is capable of simulating the impact of polders on flood processes in the Qinhuai River Basin. The polders increased the water level outside of the polders. The polders in upstream watersheds have a greater impact on the water level than polders close to basin outlets when individually distributed. The maximum water level at Dongshan section shows an increasing trend for different sized flood with the increasing number of polders in the basin, and a linear increasing trend associated with urbanization. The smaller the flood scale is, the greater the maximum water level changes.


2021 ◽  
Author(s):  
Remi Meynadier ◽  
Hugo Rakotoarimanga ◽  
Madeleine-Sophie Deroche ◽  
Sylvain Buisine

<p>The large-scale and complex nature of climate change makes it difficult to assess and quantify the impact on insurance activities. Climate change is likely affecting the probability of natural hazard occurrence in terms of severity and/or frequency.</p><p>Natural catastrophe risk is a function of hazard, exposure and vulnerability. As a (re)-insurer it is seen that changes in year-on-year losses are a function of all these components and not just the hazard.</p><p>The present study focuses, in a first step, on assessing impacts of climate change on fluvial flood risks in Europe solely due to changes in hazard itself. A stochastic catalogue of future flood risk events is derived from Pan-European data sets of river flood probability of occurrence produced within EU FP7 RAIN project. The loss modelling framework internally developed at AXA is then used to provide a geographical view of changes in future flood risks.</p><p> </p>


Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2174 ◽  
Author(s):  
Jingcai Wang ◽  
Hui Lin ◽  
Jinbai Huang ◽  
Chenjuan Jiang ◽  
Yangyang Xie ◽  
...  

Huai River Basin (HRB) is an important food and industrial production area and a frequently drought-affected basin in eastern China. It is necessary to consider the future drought development for reducing the impact of drought disasters. Three global circulation models (GCMs) from Coupled Model Intercomparison Project phase 5 (CMIP5), such as CNRM-CM5 (CNR), HadGEM2-ES (Had) and MIROC5 (MIR), were used to assessment the future drought conditions under two Representative Concentration Pathways (RCPs) scenarios, namely, RCP4.5 and RCP8.5. The standardized precipitation evapotranspiration index (SPEI), statistical method, Mann-Kendall test, and run theory were carried out to study the variations of drought tendency, frequency, and characteristics and their responses to climate change. The research showed that the three CMIP5 models differ in describing the future seasonal and annual variations of precipitation and temperature in the basin and thus lead to the differences in describing drought trends, frequency, and drought characteristics, such as drought severity, drought duration, and drought intensity. However, the drought trend, frequency, and characteristics in the future are more serious than the history. The drought frequency and characteristics tend to be strengthened under the scenario of high concentration of RCP8.5, and the drought trend is larger than that of low concentration of RCP4.5. The lower precipitation and the higher temperature are the main factors affecting the occurrence of drought. All three CMIP5 models show that precipitation would increase in the future, but it could not offset the evapotranspiration loss caused by significant temperature rise. The serious risk of drought in the future is still higher. Considering the uncertainty of climate models for simulation and prediction, attention should be paid to distinguish the effects of different models in the future drought assessment.


2018 ◽  
Vol 7 (4.34) ◽  
pp. 473
Author(s):  
Nurul Afiqa Adila Zakaria ◽  
Ahmad Shakir Mohd Saudi ◽  
Mohd Khairul Amri Kamarudin ◽  
Muhammad Hafiz Md Saad

The objective of this research is to determine the correlation of selected hydrological variables, to analyzed the significance factors influenced the occurrences of flood, to propose the flood control limit system and establish new flood risk index model in Lenggor River Basin based on secondary data derived from Department of Drainage and Irrigation (DID). Application of Chemometric technique such as Spearman’s Correlation Test, Principle Component Analysis, Statistical Process Control and Flood Risk Index created the most efficient results. Result shows water level has strong factor loading of 0.78 and significant for flood warning alert system application. The Upper Control Limit (UCL) for the water level in study area is 33.23m while the risk index for the water level set by the constructed formula of flood risk index consisting 0-100. The results show 20.6% classified as High Risk Class with index range from 70 and above. Thus, these findings are able to facilitate state government to come out with a comprehensive plan of action in strengthening the flood risk management at Lenggor River basin, Johor.  


2018 ◽  
Vol 7 (4.34) ◽  
pp. 473
Author(s):  
Nurul Afiqa Adila Zakaria ◽  
Ahmad Shakir Mohd Saudi ◽  
Mohd Khairul Amri Kamarudin ◽  
Muhammad Hafiz Md Saad

The objective of this research is to determine the correlation of selected hydrological variables, to analyzed the significance factors influenced the occurrences of flood, to propose the flood control limit system and establish new flood risk index model in Lenggor River Basin based on secondary data derived from Department of Drainage and Irrigation (DID). Application of Chemometric technique such as Spearman’s Correlation Test, Principle Component Analysis, Statistical Process Control and Flood Risk Index created the most efficient results. Result shows water level has strong factor loading of 0.78 and significant for flood warning alert system application. The Upper Control Limit (UCL) for the water level in study area is 33.23m while the risk index for the water level set by the constructed formula of flood risk index consisting 0-100. The results show 20.6% classified as High Risk Class with index range from 70 and above. Thus, these findings are able to facilitate state government to come out with a comprehensive plan of action in strengthening the flood risk management at Lenggor River basin, Johor.  


2021 ◽  
Author(s):  
Sazzad Hossain ◽  
Hannah L. Cloke ◽  
Andrea Ficchì ◽  
Andrew G. Turner ◽  
Elisabeth M. Stephens

Abstract. While flooding is an annual occurrence in the Brahmaputra basin during the South Asian summer monsoon, there is large variability in the flood characteristics that drive risk: flood duration, rate of water level rise and peak water level. The aim of this study is to understand the key hydrometeorological drivers influencing these flood characteristics. We analyse hydrometeorological time series of the last 33 years to understand flood dynamics focusing on three extraordinary floods in 1998 (long duration), 2017 (rapid rise) and 2019 (high water level). We find that long duration floods in the basin have been driven by basin-wide seasonal rainfall extremes associated with the development phase of strong La Niña events, whereas floods with a rapid rate of rise have been driven by more localized rainfall falling in a hydrological ‘sweet spot’ that leads to a concurrent contribution from the tributaries into the main stem of the river. We find that recent record high water levels are not coincident with extreme river flows, hinting that sedimentation and morphological changes are also important drivers of flood risk that should be further investigated. Understanding these drivers is essential for flood forecasting and early warning and also to study the impact of future climate change on flood.


2019 ◽  
Vol 40 (3) ◽  
pp. 427-443 ◽  
Author(s):  
Timo Assmuth ◽  
Tanja Dubrovin ◽  
Jari Lyytimäki

AbstractHuman health risks in dealing with floods in a river basin in South-Western Finland are analysed as an example of scientific and practical challenges in systemic adaptation to climate change and in integrated governance of water resources. The analysis is based on case reports and plans, on literature studies and on conceptual models of risks and risk management. Flood risks in the Northern European study area are aggravated by melt- and storm-water runoff, ice jams and coastal flooding. Flood risk assessment is linked with management plans based on EU directives as applied in the case area. National risk management policies and procedures of increasing scope and depth have been devised for climate change, water resources and overall safety, but an integrated approach to health risks is still largely missing. The same is true of surveys of perceived flood risks, and participatory deliberation and collaborative planning procedures for flood risk management in the case area, specifically for adaptive lake regulation. Health impacts, risks and benefits, socio-economic and systemic risks, and over-arching prevention, adaptation and compensation measures are not fully included. We propose a systematic framework for these extensions. Particular attention needs to be given to health risks due to flooding, e.g. from water contamination, moist buildings, mental stress and infrastructure damage and also from management actions. Uncertainties and ambiguities about risks present continuing challenges. It is concluded that health aspects of flooding are complex and need to be better included in assessment and control, to develop more integrated and adaptive systemic risk governance.


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