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1.
Zhengyin Zhou Xiaoling Wang Ruirui Sun Xuefei Ao Xiaopei Sun Mingrui Song 《Natural Hazards》2014,72(2):675-700
The present model and methodology described in Part I of this work are applied to perform a comprehensive risk analysis of the dam-break flood of five reservoirs in the Haihe River Basin, China. The results indicate that the three-dimensional numerical simulation considering complex terrain can reflect the characteristics of flood routing and the three-dimensional phenomena. Based on the simulation results, it can be concluded that the risk grades of the consequences induced by a gradual or instantaneous dam break of the Dongwushi reservoir are extremely serious, as determined through the attribute synthetic approach. The results obtained from ranking the risk by the technique for order performance by similarity to ideal solution method are that the Dongwushi reservoir has the most serious consequences when the dam breaks followed by the Lincheng reservoir, the Miaogong reservoir and the Yunzhou reservoir, and the Youyi reservoir has the least severe consequences. Though the ranking of the relatively comprehensive risk coincides with that of the consequences, the dam safety measured by the dam failure probability plays an important role in ranking the risk. A sensitivity analysis is performed by individually increasing the weight of each criterion by 20 %, and the ranking order is not changed, suggesting that the evaluation model is reasonable, stable and reliable. 相似文献
2.
为了定量获取防洪保护区在多洪源和复杂边界条件下的溃堤洪水风险信息,以非恒定流控制方程为理论基础,建立了多洪源一维河网水动力学模型和防洪保护区二维洪水演进模型,利用溃坝模型实现河道与保护区的耦联,并采用局部网格加密和相似建筑物模拟等方法处理保护区内道路等复杂边界的导阻水作用。利用所建模型模拟了长江、汉江和东荆河3种不同洪水来源, 在4种不同位置溃堤情况下汉南至白庙长江干堤防洪保护区的洪水淹没情景,采用基于淹没水深的损失率关系法对比分析了4种计算方案的淹没面积、经济损失和受灾人口。结果表明:模型构建合理、稳定性和适应性好,复杂边界对洪水演进过程影响明显,不同洪源溃堤情形的风险信息差异较大;在计算条件下,以长江发生1954年型300年一遇洪水向新溃口情形下的淹没损失最严重,其淹没面积达3 790 km2,受灾人口为196.8万人,经济损失约802亿元。研究成果可为洪水风险管理与避洪转移决策提供有力的技术支撑。 相似文献
3.
受地形影响,西南山区水源以水库为主,由于大部分水库修建时间较早,在西南季风气候降水集中影响下,存在较大的溃坝风险。溃坝洪水突发性与破坏性极强,进行水库溃坝洪水计算及洪水演进分析,是在水库大坝发生突发性安全事故时科学应对的基础。结合西南山区实际,优选溃坝洪水计算与洪水演进模型,并以云南省昌宁县河西水库为例,分析确定相关参数,分析指出了西南山区水库溃坝形态以全溃为主,具有溃坝洪水量极大、洪水演进迅速的特点。研究不仅可为河西水库制定大坝安全管理应急预案提供技术支撑,也能为该地区水库溃坝洪水及其演进分析提供参考借鉴。 相似文献
4.
为定量评估分蓄洪工程启用过程中蓄滞洪区的洪水风险等级,创建了基于力学过程的蓄滞洪区洪水风险评估模型。该模型采用二维水动力学模块计算蓄滞洪区的洪水演进过程,利用洪水中人体跌倒失稳公式及洪水中房屋、农作物损失的计算关系式,评估各类受淹对象的洪水风险等级。然后将二维水动力学模块计算的洪水要素与两个物理模型试验值进行对比,表明二维水动力学模块的计算精度良好。最后计算了荆江分洪工程启用时分洪区内洪水的演进过程,并评估洪灾中群众的危险等级和财产损失。计算结果表明:洪水演进至140 h时,蓄滞洪区群众、房屋、水稻和棉花的平均损失率分别为85%、59%、63%和72%。模型中提出的采用基于受淹对象失稳机制的洪水风险分析方法,比以往经验水深法划分风险等级的适用性更好,不仅能为洪水风险管理及蓄滞洪区启用标准制定提供参考,也能推广应用于溃坝或堰塞湖溃决等极端洪水风险评估。 相似文献
5.
The risk analysis of reservoir regulation in the flood season is crucial and provides the valuable information for reservoir flood control, safety operation, and decision making, especially under climate change. The purpose of this study is to propose a framework for reasonably estimating the variation of reservoir regulation risk including the dam extreme risk and the overtopping risk during the flood season under climate change. The framework consists of an integrated diagnostic system for detecting the climate abrupt change time, a copula function-based bivariate statistical approach for modeling the dependence between the flood peak and flood volume, a Monte Carlo simulation for generating numerous random flood peak–volume pairs, and a risk calculation model for routing the design flood hydrographs to obtain the frequency curve of the maximum water level reached in front of dam and evaluating the reservoir regulation risk. The methodology was implemented in the Chengbihe reservoir in south China by using the 55-year (1963–2017) hydrometeorological data, including temperature, evaporation, precipitation, and streamflow, in the flood season. Results show that the hydrometeorological series during the flood season changed abruptly in 1992 and the entire data can be divided into two periods (1963–1992 and 1993–2017). The dam extreme risk and overtopping risk during the two periods are assessed, respectively, and a comparison analysis is made based on different flood limit water-level schemes (185.00–188.50 m). It demonstrates that both the dam extreme risk and the dam overtopping risk increase under the influence of climate change. The dam extreme risk increases by 22.91–95.03%, while the climate change-induced increase in the dam overtopping risk is between 38.62 and 123.59%, which indicates that the dam overtopping risk is more sensitive to climate change than the dam extreme risk. The risk evaluations in the study are of great significance in the safety operation and risk management of reservoirs under future climate change.
相似文献6.
Xiaoling Wang Wenlong Chen Zhengyin Zhou Yushan Zhu Cheng Wang Zhen Liu 《Natural Hazards》2017,86(3):1147-1174
Dense buildings are the major factor affecting urban flood routing. Currently, the study of urban dam-break flood routing primarily focuses on a simplified terrain model and 2D shallow water equations, which ignore the effects of dense urban buildings. Furthermore, the complex interactions between the dam-break wave and the wall surfaces of buildings are not reflected in the results. To tackle these problems, three-dimensional flood routing with a high-precision digital model of an urban area is studied in this paper. Firstly, the vector data of various land types is extracted from a remote sensing image, and the NURBS algorithm based on the TIN algorithm is introduced to construct a three-dimensional terrain model. Coupled with the vector data and the terrain model, a three-dimensional digital model of the urban area is established. Next, a three-dimensional \(k{-}\varepsilon\) turbulence model is proposed for the flood routing simulation. A polyhedral grid with a second-order accuracy and a discrete format is used to divide the digital model of the urban area, and the governing equations are solved using the PISO algorithm. Finally, the superiority of the 3D mathematical model and the computational efficiency of the polyhedral mesh model are validated according to the urban flood routing experiments of Testa and Soares-Frazão. An urban reservoir, located in SZ City, China, is modelled to show that a dam-break flood in an urban area exhibits significant three-dimensional characteristics. Moreover, due to the surrounding buildings, the flood exhibits complex three-dimensional turbulence phenomena, including collision, reflection and vortices. 相似文献
7.
Large-scale assessment of flood risk and the effects of mitigation measures along the Elbe River 总被引：2，自引：1，他引：1
The downstream effects of flood risk mitigation measures and the necessity to develop flood risk management strategies that
are effective on a basin scale call for a flood risk assessment methodology that can be applied at the scale of a large river.
We present an example of a rapid flood risk assessment methodology for the Elbe River. A 1D hydraulic routing model is extended
by including the effect of planned (regulated and unregulated) and unintended retention (dike breaches) on the peak water
levels. We further add an inundation model for dike breaches due to dike overtopping and a macroscale economic approach to
assess the flood damage. The flexible approach to model the effects of measures by means of volume storage functions allows
for rapid assessment of combinations of retention measures of various proposed dimensions and at multiple locations. The method
allows for the comparison of the flood risk at the scale of the main river trajectory, which has not been possible for the
Elbe River to date. The model is applied to a series of exemplary flood risk mitigation measures to show the downstream effects
and the additive effects of combinations of measures on the flood risk along the river. We further demonstrate the increase
in the downstream flood risk resulting from unilateral decisions to increase the dike height at upstream locations. As expected,
the results underline the potential effectiveness of increased retention along the river. The effects of controlled retention
at the most upstream possible location and largest possible extent generate the most pronounced reduction of average annual
damage. As expected, the effect of uncontrolled retention with dike relocations is significantly lower. 相似文献
8.
Jie Yin Zhan-e Yin Xiao-meng Hu Shi-yuan Xu Jun Wang Zhi-hua Li Hai-dong Zhong Fu-bin Gan 《Environmental Earth Sciences》2011,63(2):407-414
Shanghai is physically and socio-economically vulnerable to accelerated sea level rise because of its low elevation, flat
topography, highly developed economy and highly-dense population. In this paper, two scenarios of sea level rise and storm
surge flooding along the Shanghai coast are presented by forecasting 24 (year 2030) and 44 (year 2050) years into the future
and are applied to a digital elevation model to illustrate the extent to which coastal areas are susceptible to levee breach
and overtopping using previously developed inflow calculating and flood routing models. Further, the socio-economic impacts
are examined by combining the inundation areas with land use and land cover change simulated using GeoCA-Urban software package.
This analysis shows that levee breach inundation mainly occurs in the coastal zones and minimally intrudes inland with the
conservative protection of dike systems designed. However, storm surge flooding at the possible maximum tide level could cause
nearly total inundation of the landscape, and put approximately 24 million people in Shanghai under direct risk resulting
from consequences of flooding (e.g. contamination of potable water supplies, failure of septic systems, etc.). 相似文献
9.
Midstream of the Keelung River Basin in Northern Taiwan has become highly urbanized and densely populated area. Flood inundation
along riversides frequently occurred during typhoons or rainstorms. Three protection measures, including constructions of
high-level protection levees, a diversion channel, and a detention reservoir, were proposed for flood mitigation. The main
purpose of this study is to evaluate the flood mitigation performance of the three proposed structural measures by using combined
hydrologic analyses and hydraulic routings. A semi-distributed parallel-type linear reservoirs rainfall-runoff model was used
for estimating the surface runoff. Furthermore, a 1-D dynamic channel routing model was coupled with a two-dimensional inundation
model to simulate the hydraulic characteristics of river flooding and overland flow. Simulation results of flood stages, runoff
peak discharges, and inundation extent under design rainfall scenarios were chosen as the criteria for evaluation. The results
showed a diversion channel is superior to the other two measures for flood mitigation of the study area. After the process
of environmental impact assessment, a revised diversion channel approach has been approved for construction as the major structural
measure. 相似文献
10.
A real-time operation optimization model for flood management in river-reservoir systems 总被引：1，自引：1，他引：0
In this paper, a new methodology has been developed for real-time flood management in river-reservoir systems. This methodology
is based upon combining a Genetic Algorithm (GA) reservoir operation optimization model for a cascade of two reservoirs, a
hydraulic-based flood routing simulation model in downstream river system, a Geographical Information System (GIS) based database,
and application of K-Nearest Neighbor (K-NN) algorithm for development of optimal operating rules. The GA optimization model
estimates the optimal hourly reservoirs’ releases to minimize the flood damages in the downstream river. GIS tools have also
been used for specifying different land-uses and damage functions in the downstream floodplain and it has been linked to the
unsteady module of HEC-RAS flood routing model using Hec-GeoRAS module. An innovative approach has also been developed using
K-NN algorithm to formulate the optimal operating rules for a system of two cascade reservoirs based on optimal releases obtained
from the optimization model. During a flood event, the K-NN algorithm searches through the historical flood hydrographs and
optimal reservoir storages determined by the optimization model to find similar situations. The similarity between the hydrographs
is quantified based on the slopes of rising and falling limbs of inflow hydrographs and reservoir storages at the beginning
of each hourly time step during the flood events for two cascade reservoirs. The developed methodology have been applied to
the Bakhtiari and Dez River-Reservoir systems in southwest of Iran. The results show that the proposed models can be effectively
used for flood management and real-time operation of cascade river-reservoir systems. 相似文献
11.
12.
Assessment of flood hazard,vulnerability and risk of mid-eastern Dhaka using DEM and 1D hydrodynamic model 总被引：1，自引：0，他引：1
Floods are regular feature in rapidly urbanizing Dhaka, the capital city of Bangladesh. It is observed that about 60% of the
eastern Dhaka regularly goes under water every year in monsoon due to lack of flood protection. Experience gathered from past
devastating floods shows that, besides structural approach, non-structural approach such as flood hazard map and risk map
is effective tools for reducing flood damages. In this paper, assessment of flood hazard by developing a flood hazard map
for mid-eastern Dhaka (37.16 km2) was carried out by 1D hydrodynamic simulation on the basis of digital elevation model (DEM) data from Shuttle Radar Topography
Mission and the hydrologic field-observed data for 32 years (1972–2004). As the topography of the area has been considerably
changed due to rapid land-filling by land developers which was observed in recent satellite image (DigitalGlobe image; Date
of imagery: 7th March 2007), the acquired DEM data were modified to represent the current topography. The inundation simulation
was conducted using hydrodynamic program HEC-RAS for flood of 100-year return period. The simulation has revealed that the
maximum depth is 7.55 m at the southeastern part of that area and affected area is more than 50%. A flood hazard map was prepared
according to the simulation result using the software ArcGIS. Finally, to assess the flood risk of that area, a risk map was
prepared where risk was defined as the product of hazard (i.e., depth of inundation) and vulnerability (i.e., the exposure
of people or assets to flood). These two maps should be helpful in raising awareness of inhabitants and in assigning priority
for land development and for emergency preparedness including aid and relief operations in high-risk areas in the future. 相似文献
13.
Assessing flood risk associated with waste disposals: methodology,application and uncertainties 总被引：1，自引：0，他引：1
Waste disposal sites are mostly located in lowland areas close to residential areas inducing a long-term risk of potential
environmental contamination due to flooding. During recent flood events, these areas were reportedly exposed to inundations.
This paper aims to develop a qualitative approach to assess flood risk associated with flood-prone waste disposals at the
basis of Austrian case studies. Risk is investigated as a function of the probability of an event and the consequences of
that event. The presented assessment approach is characterized as qualitative as consequences are expressed in risk categories
but not in expected (monetary) losses. The probability of inundation, the hydrodynamic impacts on considered waste disposal
sites and the expected consequences to the environment (potential emissions of hazardous substances) were linked. Derived
risk categories from “minor risk” to “serious risk” were used to express flood risk to environmental goods like groundwater
bodies, nature reserves and recreation areas. A screening of 1,064 waste disposals yielded roughly 30% of sites located within
or close to flood risk zones. Three representative case study areas were selected and investigated in detail by applying 2D
hydrodynamic models to calculate flow depths and shear stress and by developing emission scenarios. The hydrodynamic modelling
covered three hydrologic scenarios with statistical recurrence intervals of 30, 100 and 300 years. Derived leaching scenarios
ranged from minor emissions up to total erosion of the waste disposal site. Based on four parameters representing flood characteristics,
the susceptibility to erosion (flow velocity and shear stress) and the estimated leaching behaviour, a flood risk evaluation
matrix (FREM) was elaborated. The study outlines that in case of flooding the hazardous emissions could lead to partly tremendous
impacts on environmental goods. Identified uncertainties associated with considered processes were considerably high. However,
the developed qualitative approach provides a decision support aid to identify waste disposals with imminent risk for humans
and the environment. 相似文献
14.
Considering the joint probability of occurrence of high sea levels and river discharges, as well as the interactions between these sources of flooding, is of major importance to produce realistic inundation maps in river reaches affected by the sea level. In this paper, we propose a continuous simulation method for the estimation of extreme inundation in coastal river reaches. The methodology combines the generation of synthetic long-term daily time series of river discharge and sea level, the downscaling of daily values to a time resolution of a few minutes, the computation of inundation levels with an unsteady high-resolution two-dimensional model and the use of interpolation techniques to reconstruct long-term time series of water surface from a limited number of characteristic cases. The method is especially suitable for small catchments with times of concentration of a few hours, since it considers the intradiurnal variation of river discharge and sea level. The methodology was applied to the coastal town of Betanzos (NW of Spain), located at a river confluence strongly affected by the sea level. Depending on the return period and on the control point considered, the results obtained with the proposed methodology show differences up to 50 cm when compared with the standard methodology used in this region for the elaboration of flood hazard maps in accordance with the requirements of the European Directives. These results indicate the need for adaption of the standard methodology in order to produce more realistic results and a more efficient evaluation of flood hazard mitigation measures. 相似文献
15.
主要介绍以三峡为中心的长江防洪系统联合调度运行的数学模型--洪水模拟模型和水库优化调度模型.前者包括水文学洪水演进模型,一维非恒定流模型,一维和二维组合洪水模拟模型,荆江分洪区与洪湖分洪区联合运用模型,用于反映洪水在河湖中的运动及防洪措施蓄泄效果;后者由总体控制模型与模糊决策,大系统解耦以及网络分析等模型组成,用于确定使库群起到最佳防洪效果的优化调度策略. 相似文献
16.
单一水库泄洪风险分析模式和计算方法 总被引：9，自引：0，他引：9
提出了考虑调洪作用情况下单一水库泄洪布置方案的可靠度和风险分析模式及计算方法。对不考虑调洪的泄洪风险模式从理论上进行了拓展。初步分析了国内外大坝应承担的风险目标值。提出了以风险分析为基础的水库设计洪水标准选择,为合理确定泄洪布置方案及节约工程投资提供了一条较好的途径。本模式可以用于任何单一水库泄洪风险分析,同时为梯级水库泄洪布置方案的可靠度及风险分析奠定了基础。 相似文献
17.
18.
城市内涝的高效模拟对于降低内涝灾害影响、制定防灾减灾措施具有极其重要的意义。本文提出了基于雨篦子耦合地表与管网的城市降雨-产汇流-内涝全过程高效模拟方法,结合常州市双桥浜城市产汇流与内涝试验基地监测数据,分别构建了基于高效模拟算法和二维水动力算法的城市内涝模型。根据监测数据对所构建的模型进行了率定与验证,并分析对比了2种算法在不同降雨事件中的精度与可靠性。结果表明：太湖流域模型中基于雨篦子的城市水文特征单元高效模拟方法能够较为真实地反映城市内涝的具体特征,且在模型参数一致的前提下,其计算效率约为二维水动力算法的780～1 275倍,能够对城市内涝情况进行快速模拟。 相似文献
19.
Modelling flash flood propagation in urban areas using a two-dimensional numerical model 总被引：1，自引：1，他引：0
This paper reports on the numerical modelling of flash flood propagation in urban areas after an excessive rainfall event or dam/dyke break wave. A two-dimensional (2-D) depth-averaged shallow-water model is used, with a refined grid of quadrilaterals and triangles for representing the urban area topography. The 2-D shallow-water equations are solved using the explicit second-order scheme that is adapted from MUSCL approach. Four applications are described to demonstrate the potential benefits and limits of 2-D modelling: (i) laboratory experimental dam-break wave in the presence of an isolated building; (ii) flash flood over a physical model of the urbanized Toce river valley in Italy; (iii) flash flood in October 1988 at the city of Nîmes (France) and (iv) dam-break flood in October 1982 at the town of Sumacárcel (Spain). Computed flow depths and velocities compare well with recorded data, although for the experimental study on dam-break wave some discrepancies are observed around buildings, where the flow is strongly 3-D in character. The numerical simulations show that the flow depths and flood wave celerity are significantly affected by the presence of buildings in comparison with the original floodplain. Further, this study confirms the importance of topography and roughness coefficient for flood propagation simulation. 相似文献
20.
Saeed Rahimi Majid Shadman Roodposhti Rahim Ali Abbaspour 《Environmental Earth Sciences》2014,72(6):1979-1992
Flood spreading is one of the suitable strategies to control and benefit from floods which in turn improve the groundwater recharge, makes soil more fertile, and increases nutrients in soil. It is also a method for reusing sediment, which is usually wasted. Thus, selection of suitable areas for flood spreading and directing the flood water into permeable formations are amongst the most effective strategies in flood spreading projects. Having combined analytic hierarchy process (AHP) of multi-criteria decision analysis and genetic algorithm (GA) of artificial intelligence approaches, this paper addresses the problem of finding the most suitable area location for flood spreading operation in the Gareh Bygone Plain of Iran. To this end, the nine effective geodata layers including slope, alluvium thickness, geology, morphology, electrical conductivity, land use, drainage density, aquifer transmissivity, and elevation were prepared in geographic information system environment. This stage was followed by elimination of the exclusionary areas for flood spreading while determining the potentially suitable ones. Having closely examined the potentially suitable areas using the proposed methodology, the land suitability map for flood spreading was produced. The AHP and GA were used for ranking all the alternatives and weighting the criteria involved, respectively. The results of the study showed that most suitable areas for the artificial groundwater recharge are located in Quaternary Qft 2 and Qsf geologic units and in morphological units of pediment and Alluvial fans with slopes not exceeding 2 %. Finally, further evidence for the acceptable efficiency of the integrated AHP–GA method in locating most suitable flood spreading areas have been provided by such significant spatial coincidence between the produced map and the control areas located near Kowsar research station, where the earlier flood spreading projects were successfully performed. 相似文献