Implementing the European “Floods Directive”: the Case of the Po River Basin

The European “Floods Directive” 2007/60/EC (FD) asks Member States to develop flood risk maps on the bases of most appropriate and advanced tools, with particular attention on limiting required economic efforts. The question arises on how these tools should be selected so as to supply all the knowledge that is required to develop Flood Risk Management Plans (FRMPs). By analysing the implementation of the FD in the Po River Basin (Italy), the paper describes and compares two different approaches for flood risk assessment: the expert driven-qualitative approach vs. the quantitative approach based on damage models. The comparison shows, as expected, that quantitative approaches supply more useful knowledge for the development of FRMPs (and for flood risk management in general) with respect to qualitative approaches. However, they still present limits which prevent their adoption without critically consider the peculiarities of the investigated area in terms of available knowledge on hazard, exposure and vulnerability. Accordingly, considerations are supplied on how effectiveness of quantitative approaches can be maximized, towards flood risk management objectives.     

Evaluating Flood Hazard for Land-Use Planning in Greater Dhaka of Bangladesh Using Remote Sensing and GIS Techniques

Floods are a common feature in rapidly urbanizing Dhaka and its adjoining areas. Though Greater Dhaka experiences flood almost in every year, flood management policies are mostly based on structural options including flood walls, dykes, embankments etc. Many shortcomings of the existing flood management systems are reported in numerous literatures. The objective of this paper is to assess flood hazard in Greater Dhaka for the historical flood event of 1998 using Synthetic Aperture Radar (SAR) data with GIS data. Flood-affected frequency and flood depth calculated from the multi-date SAR imageries were used as hydrologic parameters. Elevation heights, land cover classification, geomorphic division and drainage network data generated from optical remote sensing and analogue maps were used through GIS approach. Using a ranking matrix in three dimensional multiplication mode, flood hazard was assessed. All possible combination of flood hazard maps was prepared using land-cover, geomorphology and elevation heights for flood-affected frequency and floodwater depth. Using two hazard maps which produced the highest congruence for flood frequency and flood depth, a new flood hazard map was developed by considering the interactive effect of flood-affected frequency and floodwater depth, simultaneously. This new hazard map can provide more safety for flood countermeasures because pixels belonging to higher hazard degrees were increased due to the consideration of higher degrees of ranks. The estimation of flood hazard areas revealed that a major portion of Greater Dhaka comprised moderate to very high hazard zone. Only a little portion (8.04%) was found to be the least vulnerable to potential flood hazard. Conversely, 28.70% of Greater Dhaka was found within very high hazard zone. Based on this study, comprehensive flood hazard management strategies for land use planning decision were proposed for the efficient management of future flood disasters.     

Flood Risk Management in Flanders: Past Developments and Future Challenges

This paper presents the state of the art of flood risk management in Flanders, a low-lying region in the northern part of Belgium which is vulnerable to flooding. Possible flood hazard sources are not only the many rivers which pass through the Flemish inland, but also the North Sea, which is sensitive to the predicted sea level rise and which can affect large parts of the Flemish coastal area. Due to the expected increase in flood risks in the 21st century, the Flemish government has changed its flood management strategy from a flood control approach to a risk-based approach. Instead of focusing on protection against a certain water level, the objective now is to assure protection against the consequences of a flood, while considering its probability. In the first part, attention is given to the reasoning and functioning of the risk-based approach. Recent improvements to the approach are discussed, as well as the GIS-implementation of the entire model. The functioning of the approach is subsequently demonstrated in two case studies. The second part of the paper discusses future challenges for the flood risk management in Flanders. The driving force behind these challenges is the European Directive on the assessment and management of flood risks, which entered into force in 2007. The Flemish implementation of the directive is discussed and situated in the European landscape. Finally, attention is given to the communication of flood risks to the general public, since the “availability” of flood risk management plans is among the requirements of the EU Floods Directive.     

中国洪水灾害危险程度区划

洪灾的含义包括洪水和灾害两个方面。本文从气象、径流和地形三因素考虑，采用成因分析的方法，制成了洪水危险程度区划图。以耕地和人口为经济因素指标，考虑洪水造成的灾害，制作成洪灾危险程度区划图。本文制作的区划图是客观的，已得到了一些领域专家的认可，可以作为防洪规划等宏观决策的依据。     

关于我国洪水风险图编制工作的思考

我国第一张洪水风险图是1984年绘制完成的,到现在,无论是在洪水风险理论、洪水风险分析方法和模型、洪水风险特征展示和绘制技术,还是在洪水风险图编制规范的制订等方面都有了长足的进步,并运用二维非恒定流的洪水分析模型陆续研究绘制了部分城市、蓄滞洪区、洪泛区和防洪保护区约10万km2的洪水风险图,形成了具有较高水平的洪水风险图技术体系和一定规模的人才队伍,一些洪水风险图成果已开始运用于实际防洪工作之中.今后还应进一步明确洪水风险图的使用对象和用途,落实洪水风险图制作的行政管理机制、编制计划和经费投入,构建若干官方认可的规范化的风险分析和风险图制作平台,不断弥补基础信息的不足.     

洪水管理、风险评估和洪泛区区划

洪水风险评估包括洪峰、洪量、水位和洪水过程.从安全角度来看,洪水风险评估对于水电工程、防洪工程的设计和运行是十分重要的.洪水管理旨在最大限度地减少洪泛区的洪灾损失,因此根据洪水发生的量级和频率进行洪水风险评估、制作洪水风险图对于洪水管理至关重要.目前在印度采取的主要防洪措施有:进行堤坝溃决风险分析、发布洪水预警、制作洪水风险图或洪灾风险图等.根据洪灾风险评估确定不同的保险费用,并据此推行防洪保险计划,可能非常有助于洪泛区的区划工作.地形等高线图是进行洪泛区区划的前提条件.根据这些图集和洪水风险评估,洪泛区能够按照区划进行开发活动的分类管理.     

欧洲洪水风险图编制经验的启迪

从洪水风险图发展历程看,欧洲与我国比较相似,洪水风险图的起步时间比较接近,目前也都处在一个大的发展阶段.本文从洪水风险图的发展背景、洪水风险图的种类、洪水分析计算方法、洪水风险图的制作单位和运用方式等多个方面阐述了欧洲的主要做法,对比了与我国洪水风险图编制工作的异同.为进一步适应我国洪水风险管理工作的需要,建议我国尽早开展洪水危险等级划分标准的研究以及包含风险信息的洪水风险图绘制工作,规范参与洪水风险图绘制的洪水分析计算工具,进一步明确洪水风险图的角色和使用方法等问题.     

防洪减灾风险管理研究综述

主要对水文风险、水力风险、经济风险、风险决策和洪水保险五个方面的风险管理方法在防洪减灾中的研究现状进行归纳和评述 .其中水文风险的研究重点分为线型选择、参数估计、风险率计算三部分 ;水力风险的研究主要集中在水库泄洪风险及河道或洪泛区的洪水演进研究 ;经济风险分析主要集中在防洪费用效益的风险分析 ;风险决策研究通常表现为防洪问题的可靠性规划和多目标风险分析两种形式 ;洪水保险的研究主要是利用模拟模型来推导一个最优洪水保险策略 .文末阐述了防洪减灾风险管理的发展趋势     

我国推进洪水风险图编制工作基本思路的探讨

编制洪水风险图是推进洪水风险管理的一项重要的基础工作,也是一项技术性、政策性很强的工作."十一五"期间我国将大力加强洪水风险图的编制工作,为此迫切需要理清思路,明确怎么做.在总结近几十年国内外风险图制作经验教训的基础上,提出今后我国的洪水风险图编制工作应坚持分三步走,加强前期基础研究,并明确洪水风险图的法律地位.     

洪水灾害危险性评价方法的研究与改进

洪水风险分析是防洪非工程措施的重要组成部分,而洪水危险性评价是风险分析的基础。现有的洪水危险性评价方法由于需要获得淹没水深,在对洪水风险预测时要求复杂的水力学模型和高分辨率数据的支撑,但业务化过程中常常无法满足数据要求,为了简化洪水危险性评价的过程,确保评价结果的准确性,提出了一个新的简单且综合的洪水危险性评价指标(FHI,Flood Hazard Index)。该指标以GisNet和ArcGIS为软件平台,结合分布式水文模型,依据洪灾的形成机理,综合考虑分布式流量与地形指数。结合北京山区红螺谷流域的具体情况,对新指标进行了对比检验。结果显示,FHI能够真实地反映区域洪灾随空间变化的趋势,为未来洪水危险性评价与预测的研究,提供了一个全新的思路,对洪水风险研究体系的完善具有重要的现实意义。     

洪水灾害风险管理的理论框架探讨

洪水灾害管理是一项复杂的系统工程，在防洪减灾工程理论与实践中具有重要意义。根据洪水灾害风险的形成机制，提出并系统地阐述了由洪水灾害危险性，洪水灾害易损性和洪水灾害灾情组成的洪水灾害风险结构，在该风险结构基础上把洪水灾害风险管理的理论框架进一步展开为洪水灾害危险性分析，洪水灾害易损性分析，洪水灾害灾情分析和洪水灾害风险决策分析4个具有相互联系的部分。     

我国洪水风险图编制技术标准化的探讨

洪水风险管理需要将工程和非工程措施结合起来,编制洪水风险图是非工程措施中降低洪水风险的重要手段之一.我国洪水风险图编制已经进入全国试点阶段,但至今还没有建立一套指导和规范洪水风险图编制的技术标准.本文结合我国的国情和流域特征,对我国洪水风险图编制中的基础资料、洪水泛滥模拟模型、洪灾损失评价模型以及风险图的表现内容等基本技术和方法的标准化进行了探讨,并提出了我国洪水风险图编制技术标准化和规范化过程中急需解决的问题.     

A GIS-Based Spatial Multi-Criteria Approach for Flood Risk Assessment in the Dongting Lake Region,Hunan, Central China

Floods, the most common natural hazard in the world, cause serious loss in terms of lives, buildings, and infrastructures. As a consequence, the need for flood risk assessment has become critical. Using a semi-quantitative model and fuzzy analytic hierarchy process (FAHP) weighting approach, this paper assessed flood risk in the Dongting Lake region, Hunan Province, Central China, an area where flood hazards frequently occur. The model was designed using spatial multi-criteria analysis (SMCA) techniques in a Geographic Information System (GIS). A GIS database of indicators for the evaluation of hazard and vulnerability was created. Each indicator was analyzed, standardized, and weighted; after which, the weights of the indicators were combined to obtain the final flood risk index map. Using the flood risk index, the study area was classified into five categories of flood risk: very low, low, medium, high, and very high. The high and very high risk zones are mainly concentrated in the northern and central plains. The results obtained can provide useful information for decision makers and insurance companies.     

Morphodynamische Aspekte der Ökohydraulik und Habitatmodellierung im Kontext der rechtlichen Rahmenbedingungen

Hydromorphological status and risk assessments are crucial with regard to the planning of measures in keeping the aims of the EU’s Water Framework Directive. However, both status assessments and integrative habitat models are often based on one-time terrain measurements and therefore offer only limited potential for assessing dynamic potential. The aim of the paper is to address the importance of dynamic processes in rivers and to emphasize their importance for water management practice. In the context of an integrative habitat assessment, three different forms of dynamic processes need to be taken into account: (1) flow dynamics, (2) morphodynamics and (3) longer-term changes, e.g. those caused by global warming. However, given the various types of use, these dynamic processes are often affected by anthropogenic pressures. This paper describes to what extent and in which form these dynamic processes are/can be decisive for the quality and quantity of aquatic habitats. Here, the river-type-specific differences with regard to habitat assessment are also discussed. Case studies from rivers in southern Styria and Carinthia underline the significance of morphodynamics, both for the goals of the Water Framework Directive and with regard to the implementation of the Floods Directive, as self-forming processes may be as well important for flood protection issues     

资料匮乏山丘区山洪灾害风险区划分

由于目前山洪灾害风险分析计算的方法大多来源于丰富的水文资料和山洪资料,不太适用于资料匮乏的北方山丘区,为此提出了适合资料匮乏地区山洪灾害风险图的计算及划分方法,旨在供我国北方资料匮乏地区的山洪灾害的风险分析参考。     

考虑时间变化的洪涝灾害损失评估

洪涝灾害是对我国影响最大的自然灾害之一。聚焦灾害损失评估问题,本文构建了考虑时间变化的洪涝灾害损失函数。一方面,表征灾害损失随着致灾因子强度先递增、而后增幅趋缓的静态S型曲线关系;另一方面,通过量级、形状和位置三个参数综合考虑灾害损失随时间的动态变化情况。基于《中国水旱灾害防御公报》提供的受灾人口、直接经济损失数据,对于各省级行政区2006—2021年洪涝灾害损失进行评估分析。结果表明：通过拟合洪涝灾害损失函数,洪涝灾害损失关于致灾因子强度和时间的三维空间散点图可有效地拓展成为连续的三维空间曲面及二维空间热力图。各省级行政区受灾人口整体上呈现出逐年下降的特征,但随致灾因子强度的增加而趋于增加。各省级行政区直接经济损失则表现出明显的差异,随时间呈现出大幅下降、缓慢下降和略有增加等不同特征。考虑时间变化的洪涝灾害损失函数是变化环境下灾害评估的有效工具,可为区域洪涝灾情评估提供借鉴和参考。     

对洪水分级的浅见

洪水的等级划分应考虑流量、水位、防洪能力及灾害等因素,综合这些因素把洪水分成5个等级。1、2级洪水,洪水流量小,水位低,基本无灾;3级洪水,洪水流量较大或水位较高,有一定灾害;4级洪水,为大洪水或高水位,有较大灾害;5级洪水,为特大洪水或高水位,灾情严重。     

Flood risk assessment in the region surrounding the Bangkok Suvarnabhumi Airport

Flood hazard, vulnerability, and risk assessments were conducted in the area surrounding the new Bangkok International Airport. A hydrodynamic model was used to simulate the flood flow through the study area. Results show different levels of flood hazard for risk zones for 25-, 50- and 100-year return periods of rainfall.     

西林县山洪灾害分析评价

为全面和准确地掌握西林县山洪灾害威胁区小流域暴雨洪水基本特征,了解山丘区暴雨、山洪与灾害之间的关系,获知沿河村落的山洪暴发临界雨量,进一步提高区域山洪灾害防治能力,基于工作底图、小流域基础属性数据和山洪灾害调查成果,开展小流域暴雨洪水特性分析、沿河村落防洪现状评价和预警指标分析,获得了良好的山洪灾害分析评价成果。结合西林县实际情况,提出了针对性意见和建议,可供下一步山洪灾害防治参考。     

海南省五指山市山洪灾害分析评价

基于工作底图、基础数据和山洪灾害调查数据等资料,对五指山市进行了山洪灾害分析评价,并以通什水上游的军民村(TS06)小流域作为实例介绍山洪灾害分析评价流程,主要评价内容为小流域暴雨洪水计算、现状防洪能力分析和危险区划分、预警指标分析,最后,针对五指山市山洪灾害防治提出了建议。