An AMSR-E Data Unmixing Method for Monitoring Flood and Waterlogging Disaster

Spectral remote sensing technique is usually used to monitor flood and waterlogging disaster.Although spectral remote sensing data have many advantages for ground information observation,such as real time and high spatial resolution,they are often interfered by clouds,haze and rain.As a result,it is very difficult to retrieve ground information from spectral remote sensing data under those conditions.Compared with spectral remote sensing tech-nique,passive microwave remote sensing technique has obvious superiority in most weather conditions.However,the main drawback of passive microwave remote sensing is the extreme low spatial resolution.Considering the wide ap-plication of the Advanced Microwave Scanning Radiometer-Earth Observing System(AMSR-E) data,an AMSR-E data unmixing method was proposed in this paper based on Bellerby's algorithm.By utilizing the surface type classifi-cation results with high spatial resolution,the proposed unmixing method can obtain the component brightness tem-perature and corresponding spatial position distribution,which effectively improve the spatial resolution of passive microwave remote sensing data.Through researching the AMSR-E unmixed data of Yongji County,Jilin Provinc,Northeast China after the worst flood and waterlogging disaster occurred on July 28,2010,the experimental results demonstrated that the AMSR-E unmixed data could effectively evaluate the flood and waterlogging disaster.

Flood and Waterlogging Disaster Damage Evaluation in Middle-Lower Yangtze River by 3S technology

The evaluation method, model and process for the flood and waterlogging disaster condition by GIS,RS and GPS technology and the method for setting up disaster condition database, dyke database and historical disaster damage database are presented. An index of flood damage degree(FDD) used to evaluate the relative degree of disaster loss and divide flood and waterlogging area is suggested. The value of flood damage degree can be calculated as follows :taking the various disaster losses of sample area in a base year as standard value and computing the ratios of various disaster loss values in different areas and years to the standard flood disaster loss values, then summing up the weighted ratios. The computed results are the value of flood damage degree in the every year. The macroscopic flood disaster distribution can be evaluated by the values of flood loss degree.

Risk Identification for the Ecological Environment of Flood Disasters Based on the Life Cycle

Aiming at the complexity of ecological environment risk of flood disaster, the life cycle of flood disaster is defined based on the relevant literatures, which is divided into incubation period, development period, outbreak period, recession period and extinction period. The characteristics of each period are analyzed. Further, the main risks for ecological environment faced at each stage under the life cycle of flood disaster are studied systematically to form the systematic ecological environment risk system for flood disaster.

Urban Flood Disaster Risk Assessment and Planning Response: A Case Study of Handan, Hebei Province

Flood disaster is a serious threat to urban security,and flood control and drainage planning is an important measure to ensure urban security.This paper takes planning guidance to empirical research as the main axis.On the basis of meteorological data and spatial data,through the analysis on the risk of disaster-causing factors of flood disasters,the sensitivity of disaster-pregnant environment,the vulnerability of disaster-bearing bodies and the ability of disaster prevention and mitigation,12 indicators are selected to construct a comprehensive evaluation index system for flood disaster risk.Handan City is taken as an example to study the spatial distribution characteristics of flood disaster risk.Based on AHP,weights are assigned to the evaluation indicators of flood disasters in the system,and the risk visualization is carried out in GIS.According to comprehensive risk assessment results,it could put forward corresponding disaster prevention planning strategy for defending flood disaster in Handan City.

Analysis and Zoning of Rainstorm Flood Disaster Risk in Huaihe River Basin

Taking the rainstorm flood disaster of Huaihe River basin as the research object,according to the principles of risk assessment for natural disasters,starting from the fatalness of inducing factors and the vulnerability of hazard bearing body,the weight of each impact factor was calculated by using AHP. By using spatial analysis and statistical function of GIS,the integrated risk chart of rainstorm flood disaster in Huaihe River basin was obtained. The results showed that the high risk areas of rainstorm flood disaster in Huaihe River basin mainly distributed in the southern part of Henan,the central northern part of Anhui and eastern part of Jiangsu Province. Due to higher fatalness of inducing factors in southern Henan,there was high risk in the region. Central Anhui and east Jiangsu were not only high-fatalness zones but also high vulnerability zones of population and economy.

基于MIKE FLOOD耦合模型模拟的城市内涝对道路安全风险的影响评估

城市内涝风险评估对预防洪涝灾害有重要作用,但现有研究很少针对道路安全风险评估。以重庆市秀山县为研究对象,通过构建MIKE FLOOD耦合模型对道路安全风险进行评估。结果表明:地面积水深度主要集中在0.05~0.15 m,不同重现期(P=1%~20%)降雨下的水深在空间分布上大体呈一致状态,积水时间主要集中在60~90 min,积水流速主要大于0.8 m/s。其中,老城区部分区域的基础设施安全风险以极高风险(水深>0.4 m)为主,其余区域为轻微风险(水深<0.5 m)为主,而行人安全风险以Ⅲ级(危险性指数1.25~2)为主,其余区域则以Ⅰ级(危险性指数<0.75)为主。大部分路段的交通运行状况以畅通等级(保留系数>0.7)为主,但部分路段遇暴雨时中断(保留系数=0)。研究结果可为城市内涝发生前的交通管控和通行预警提供科学依据。

IMPACT OF FUTURE SEA LEVEL RISE ON FLOOD AND WATER LOGGING DISASTERS IN LIXIAHE REGION

Lixiahe region is one of the susceptible area to flood and waterlogging disasters in China due to its low topographic relief and having difficulty in draining floodwater away.The condition will be more serious if sea level rises in the future.The estimated results by some scientists indicate that the sea level could rise probably 20-100 cm by 2050.However,what the effect will future sea level rise exerts on flood drainage and on flood or waterlogging disasters? A hydrological system model has been developed to study the problem in the lower reaches of the Sheyang River basin.Predicted results from the model show that,if sea level rises,drainage capacity of each drainage river will decrease obviously,and the water level will also rise.From the change of drainage capacity of drainage rivers the trends of flood and waterlogging disasters are analyzed in the paper if the severe flood that happened in the past meets with future sea level rise.Some countermeasures for disaster reduction and prevention against sea-level rise are put forward.

Mainstreaming Disaster Risk Reduction into Housing Development in Keko Machungwa

In Tanzania 80% of the population live in informal settlements. Most of these settlements are built in areas that are susceptible to extreme weather conditions such as flooding. Such conditions have significantly contributed to the destruction of housing stock and other valuable properties. There is considerable awareness amongst people living in the informal settlements, government representatives and other key stakeholders about the various flood risks affecting informal settlements. Based on this understanding, several attempts to minimize flood risks have been initiated in Dar es Salaam, Tanzania, yet these initiatives have largely failed to deliver the desired impacts. This article aims to investigate core reasons for this through a case study of Keko Machungwa Informal settlement in Dar es Salaam City. The study explores the extent to which mainstreaming of disaster risk reduction (DRR) in housing development in informal settlements has been considered and implemented, and recommends measures for improvement. Key methods employed for the research included physical observation, household interviews, mapping, photographing, and in-depth interviews. Overall, the study found that mainstreaming of DRR in housing development was hardly practiced at the household level, as houses were predominantly being built without resistant building materials and supervision of relevant professionals. In order to mainstream DRR in housing development in informal settlements, it is recommended that mainstreaming DRR be embedded in laws and policies, highly vulnerable parts of the settlement be declared protected wetland and that the government direct its efforts towards regulating, controlling and monitoring the housing development sector. That letter can be achieved by emphasizing the use of flood resistant building materials and establishing resilient infrastructures for flood mitigation in every flood prone informal settlement.

基于LisFlood-SWMM耦合模型的城市停车场所积水风险评估

全球变暖气候变化导致特大暴雨频发,城市化水平提高下建成区面积不断增加,由此引发的洪涝灾害风险居高不下,城市内涝发生时市内车辆泡水现象频发。本文以深圳市福田区城市停车场为研究对象,利用POI(兴趣点)数据爬取方法构建了深圳市福田区的停车场数据库,根据LisFlood-SWMM模型模拟了不同降雨情景下的淹没情况。以此为基础,划分了内涝造成的积水风险等级,得到了不同降雨情景下城市停车场所积水风险评估,并提出了风险防范措施建议,对我国城市停车场积水风险评估具有一定参考意义。

GIS-based Risk Zone of Flood Hazard in Anhui Province

[Objective] The aim was to study the flood disaster risks in Anhui Province based on GIS. [Method] Taking country as basic unit, the 1∶ 250 000 basic geographic data in Anhui Province as basis, from the angle of flood disaster hazard and economic vulnerability, and by dint of the calculation of the weight of each impact factor with entropy-based fuzzy AHP method, flood risk assessment model was established to study the flood disaster risks zoning in Anhui Province. Using nearly 10 years of disaster information in Anhui Province, the flood risk zoning of Anhui Province was studied. And the risks evaluation results of flood disaster risks in Anhui Province in recent 10 years were checked. [Result] The regional difference of flood disaster in Anhui Province was large. The most serious area of flood disaster was in Lingquan in Fuyang and Lingbi in Huaibei. The risks degree degraded from south mountainous area in north Anhui Plain to the mountainous area of west Anhui Province, from Huaibei Plain to the hilly area of Jianghuai and mountainous area of south Anhui Province. The disaster situation in Anhui Province in recent 10 years suggested that the areas suffering from serious economic losses were in Lingbi, Guzheng and Huainan in the south part of Huaibei Plain. The places having serious agricultural crops damages were in Tangshan and Xiao County in Huaibei Plain. Besides, the Jingzhai area in the Dabieshan in west Anhui Province also had serious agricultural crops in Jinzhai. Other places had limited disaster-stricken impacts; the distribution of disaster-stricken population and impacted area of agricultural crops were basically consistent. Therefore, the risk evaluation of flood disaster of Anhui Province based on GIS was basically consistent with reality. [Conclusion] This GIS-based flood risk zoning method had good practicability.

Numerical Study on the Impact of GongJi Road Rain Pump on the Waterlogging in Huinan, Pudong District

To study the rainstorm waterlogging disaster in Huinan, Pudong District, an urban waterlogging model coupled with the rainfall runoff sub-model, underground network sub-model and the overland flow sub-model has been set up by MIKE FLOOD. After the validation with the actual reports of the waterlogging in Huinan on Oct. 8th, 2013, the model is adopted to simulate the overland flood before and after Gongji Road Rain Pump works to study the impact of Gongji Road Rain Pump on the waterlogging disaster. The results are analyzed and the conclusions are obtained: when Gongji Road Rain Pump runs, the total flooded area will significantly decrease to .49 km2, about 21%, meanwhile, the drowned duration will be shortened in 6 hours, ahead 10 hours. Therefore, Gongji Road Rain Pump can alleviate the waterlogging, but some other measures are still needed to be taken to solve the waterlogging disaster.

Global Aspects of Flood Risk Management

Various flood disasters in the last decade have confirmed that the risk from flooding has been increasing significantly worldwide. The driving factors for the risk are the unabated increase in global population, the concentration of people in high-risk areas such as coasts and flood plains, the rise in vulnerability of assets, infrastructure and social systems, and the consequences of climate change. Risk reduction is based on comprehensive risk management from identification of the hazard and assessing the risk to building defenses. To achieve this, general awareness at all levels in a society is key. It is not sufficient merely to be aware of the situation-findings must be acted upon with no significant delay. Flood-related computations have progressed considerably in recent years, but model results can only be as good as their input data. Modeling floods and flood losses is very complex, as model parameters are subject to change during an event and conditions sometimes greatly depend on small-scale factors.

我国沿海地区城市洪(潮)涝成因及应对策略——以深圳市为例

沿海地区受地理位置、全球气候变化和城市化快速发展等影响,城市洪(潮)涝灾害频发,已成为影响我国沿海地区城市公共安全的突出问题,严重制约经济社会可持续健康发展。根据城市水文循环过程,综合考虑致灾因子、孕灾环境和承灾体等,将沿海地区城市洪(潮)涝成因概括为“先天不足—后天变化”两个方面,并以深圳市为例进行了深入分析。在此基础上,从提高防洪(潮)和排涝能力,协调防洪、除涝、排水标准,科学规划城市发展,充分考虑地下空间竖向设计,全面加强流域统一管理5个方面提出沿海地区城市洪(潮)涝应对策略,为沿海地区城市防洪(潮)、除涝工程体系建设和城市洪(潮)涝风险管理提供支撑。

变化条件下长江下游地区防洪问题与韧性提升对策

长江下游地区圩区广布、城镇众多、水网稠密,汛期受长江上中游来水、长江口及沿海高潮和本地暴雨共同威胁。目前,该地区形成了以江河湖海堤防为基本屏障,以水库、湖泊和蓄滞洪区为洪涝调蓄空间,以长江及区域主要河道为洪涝行泄通道,各类闸站相配套的防洪治涝工程体系。但近年来长江流域大洪水事件表明,长江下游防洪工程薄弱环节仍然明显,蓄泄矛盾突出,空间统筹治理和工程协同调度不足,灾害风险预防管控存在盲区,同时还面临着气候水文和经济社会条件双重变化的复杂形势。为强化长江下游地区洪涝灾害风险集成调控、提升应对大洪水的韧性,需在稳固长江干流防洪屏障和行洪主通道的基础上,科学优化各水系洪涝蓄泄格局、加快补齐防洪基础设施短板、促进洪涝治理空间均衡协调、加强洪涝灾害风险管控预防、提升防洪管理智慧化水平。同时,还应针对长江下游地区重大防洪科技问题开展系统深入研究。

利比亚德尔纳2023年极端洪水模拟复盘分析

全球气候变化背景下,极端强降雨和洪涝等水文事件的极值屡屡刷新历史记录,造成重大损失。2023年9月10—11日,在地中海飓风“丹尼尔”的影响下,利比亚东北部地区发生罕见特大暴雨,引发德尔纳市上游两座水库接连溃决,造成巨大人员伤亡。本文对德尔纳市极端洪水事件进行了梳理,并以德尔纳市洪灾及受影响区域为研究对象,建立了二维水动力模型,对溃坝洪水进行了模拟和复盘分析。通过哥白尼应急管理服务(Copernicus Emergency Management Service,CEMS)提供的受灾数据对模型结果进行对比验证(CEMS持续监测欧洲和全球即将发生或实时发生的灾难事件)。结果显示,影响德尔纳市的溃坝洪水持续了2 h左右,对城市的破坏主要集中在前30 min。本次复盘分析了德尔纳市溃坝洪水演进与风险分布特征,可为我国城市地区大坝溃决风险防控、早期预警和应急管理提供参考借鉴,同时也可为世界其他地区的大坝溃决风险防控、早期预警和应急管理提供参考借鉴。

考虑人群活动的城市场所洪涝灾害风险动态评估——以深圳市为例

为了揭示人群动态活动对城市洪涝灾害风险的影响,本文引入场所视角,建立了考虑人群活动的城市场所洪涝灾害风险评估模型,以深圳市福田区4个典型社区为例分析了工作日和休息日的白天、晚上4个时段下不同类型场所的洪涝灾害风险变化。结果表明:①除危险性以外,频繁的人群活动亦会增加场所的洪涝灾害风险,与人群活动相关的指标权重达0.31;②不同类型场所的洪涝灾害风险差异显著,且随着人群活动动态变化,生活场所平均风险最高,在4个时段波动较小;居住型混合场所洪涝平均风险次之,但晚上时段比白天高25%左右;商业场所、公共服务场所和办公型混合场所平均风险也较高,在工作日白天高于其他时段;绿色休闲场所在4个时段风险都最低;③居住型社区和综合型社区的洪涝风险存在显著差异,居住型社区为持续性高风险社区,其高风险场所占比在4个时段均超过40%,尤其在晚上达60%,而综合型社区风险呈现出工作日白天高于其他时段的特征,其高风险场所比例最高达54%。

考虑降雨-洪水-泥沙作用下的淤地坝溃决致灾风险评估

淤地坝一旦遭遇极端降雨极易导致洪水漫顶溃决,将对下游人民群众造成极大威胁,亟需开展淤地坝溃决风险定量评估。现有研究忽略泥沙对溃决致灾过程的影响。本研究通过分析降雨诱发的泥沙对溃决致灾的影响过程,揭示降雨-洪水-泥沙作用下的溃决致灾机制,建立考虑降雨-洪水-泥沙作用下的淤地坝溃决致灾风险定量评估模型,将传统的“降雨-洪水”研究发展为“降雨-洪水-泥沙”,实现溃决坝体的精准判定和风险定量评估。将模型应用于王茂沟流域两次溃决案例,并评估不同重现期降雨量的溃决致灾风险。结果表明:考虑泥沙对溃决致灾过程的影响,判定关地沟3坝、背塔沟坝和康和沟3坝溃决,判定结果与实际溃决情况吻合,忽略泥沙影响则背塔沟坝的溃决判定存在差异。与忽略泥沙对溃决致灾的作用相比,考虑泥沙作用2017-7-26降雨下关地沟3坝、背塔沟坝和康和沟3坝起溃时间分别提前11 min、13 min和7 min,有利于及时发出预警,快速撤离两岸群众,提升了淤地坝预警的准确度。不同重现期降雨量下,关地沟3坝10年一遇溃决流量为4.82 m^(3)/s,200年一遇溃决流量为5.97m^(3)/s。黄柏沟2坝和关地沟4坝在目前淤积情况下,可抵御200年一遇降雨。

基于AHP-EWM的流域山洪风险综合评价研究

为合理评估并量化小流域山洪灾害风险,结合小流域山洪特点,从危险性、脆弱性和防灾减灾3个方面构建小流域山洪风险评价指标体系。采用层次分析法(AHP)、熵权法(EWM)分别确定指标的主、客观权重,结合博弈集结模型确定指标综合权重,最后基于幂指数法得到小流域山洪风险综合评价值,从而确定综合风险等级。以湖北省随州市柳林镇8·12山洪为例开展小流域山洪风险评价,最终得出其综合评价值为0.634 9,为较高风险,与柳林镇实际情况一致。该研究结果可为小流域山洪灾害预防提供理论指导,为灾害的应急救援提供决策支持。

基于空间信息格网的南京市洪水风险评估

分别采用MIKE模型和ArcGIS平台搭建洪水风险自然属性和社会属性空间信息格网并进行格网叠加,构建洪水风险评价指标体系,利用层次分析法和熵权法确定主客观权重,进而计算得出洪水风险综合指数并对南京市秦淮区3个相邻街道进行洪水风险评估。结果表明:不同降雨强度下,洪水风险综合指数西北部较高、东南部较低、易受损敏感区相对较高;随着降雨强度增大,洪水风险综合指数较高的区域范围不断扩大;研究区主要积淹点均处于洪水风险综合指数较高区域;基于空间信息格网的洪水风险评估可为精细化、动态化的洪水灾害风险评估与洪水管理提供参考。

Community-based scenario modelling and disaster risk assessment of urban rainstorm waterlogging

Scenario modelling and the risk assessment of natural disasters is one of the hotspots in disaster research. However, up until now, urban natural disaster risk assessments lack common procedures and programmes. This paper selects rainstorm waterlogging as a disaster to research, which is one of the most frequently occurring hazards for most cities in China. As an example, we used a small-scale integrated methodology to assess risks relating to rainstorm waterlogging hazards in the Jing＇an District of Shanghai. Based on the basic concept of disaster risk, this paper applies scenario modelling to express the risk of small-scale urban rainstorm waterlogging disasters in different return periods. Through this analysis of vulnerability and exposure, we simulate different disaster scenarios and propose a comprehensive analysis method and procedure for small-scale urban storm waterlogging disaster risk assessments. A grid-based Geographical Information System （GIS） approach, including an urban terrain model, an urban rainfall model and an urban drainage model, was applied to simulate inundation area and depth. Stage-damage curves for residential buildings and contents were then generated by the loss data of waterlogging from field surveys, which were further applied to analyse vulnerability, exposure and loss assessment. Finally, the exceedance probability curve for disaster damage was constructed using the damage of each simulated event and the respective exceedance probabilities. A framework was also developed for coupling the waterlogging risk with the risk planning and management through the exceedance probability curve and annual average waterlogging loss. This is a new exploration for small-scale urban natural disaster scenario simulation and risk assessment.