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.     

日本综合防洪减灾对策及洪水风险图制作

洪水灾害是我国最频繁发生和最严重威胁国民安全与经济发展的自然灾害之一.我国洪泛区的面积、洪泛区内的人口和资产占全国的比例以及大都市周边的城市化进程与日本十分相似.日本在洪水管理方面的一些先进理念、技术和实践,特别是在洪水风险图编制方面的成熟经验,值得我们参考和借鉴.     

Uncertainty Estimation in Flood Inundation Mapping: An Application of Non‐parametric Bootstrapping

Disaster prevention planning is affected in a significant way by a lack of in‐depth understanding of the numerous uncertainties involved with flood delineation and related estimations. Currently, flood inundation extent is represented as a deterministic map without in‐depth consideration of the inherent uncertainties associated with variables such as precipitation, streamflow, topographic representation, modelling parameters and techniques, and geospatial operations. The motivation of this study is to estimate uncertainties in flood inundation mapping based on a non‐parametric bootstrapping method. The uncertainty is addressed through the application of non‐parametric bootstrap sampling to the hydrodynamic modelling software, HEC‐RAS, integrated with Geographic Information System (GIS). This approach was used to simulate different water levels and flow rates corresponding to different return periods from the available database. The study area was the Langat River Basin in Malaysia. The results revealed that the inundated land and infrastructure are subject to a flooding hazard of high‐frequency events and that the flood damage potential is increasing significantly for residential areas and valuable land‐use classes with higher return periods. The proposed methodology, as well as the study outcomes, of this paper could be beneficial to policymakers, water resources managers, insurance companies and other flood‐related stakeholders. Copyright © 2017 John Wiley & Sons, Ltd.     

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.     

湖北省山洪灾害防治区划研究

根据湖北省现有的小河流域山洪灾害资料，分析其发生的特点及频率，参照当地降雨分布、地形地质条件、社会经济情况等，以小流域为单元，以GIS为技术手段，编制出山洪灾害防治区划图，图中分为重点防治区与一般防治区，对各区的特殊问题作出分析总结。     

论抵御''98洪水与洪水风险管理

1998年长江流域发生了自1954年以来又一次全流域性大洪水，嫩江和松花江流域也发生了超历史记录的特大洪水．从抵御’98洪水中得出，必须改变单纯的抵御洪水的观念，要对洪水实行全过程风险管理．进行洪水风险管理，最主要的是制定针对洪水灾害的政策．并进一步分析了蓄滞洪区的管理，应加强以下几方面的建设：（1）控制和减少人口；（2）加强安全设施建设；（3）绘制洪水风险留，建立和完善避难的预报和预警系统；（4）建设分蓄洪控制工程；（5）严格土地利用规划及管理，调整产业结构；（6）实行洪水保险制度．     

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。     

基于MIKE FLOOD的中小河流溃堤洪水风险分析

近年来洪水引发的中小河流堤防溃决等洪水灾害风险问题凸显,因此进行溃堤洪水风险分析对于加强中小河流的洪水管理及减少溃堤洪水带来的损失具有十分重要的意义。以江西省罗塘河为例,借助MIKE软件中的MIKE 11、MIKE 21及其耦合模块对罗塘河遭遇10a一遇及20a一遇洪水进行溃堤洪水演进模拟。然后依据灾害系统理论从洪水的危险性和易损性两方面选择淹没水深、淹没流速、淹没历时等7个指标构建溃堤洪水风险评价指标体系。最后利用GIS技术与层次分析法对罗塘河洪水风险进行了评价。结果表明:洪水危险区面积为0.19 km~2,占研究区总面积的2.18%,主要分布在地势低洼的富港地区;重灾区和中灾区面积为1.25 km~2,占研究区总面积的14.37%,主要分布在重文和蒋元乐家;安全区为研究区域内洪水没有到达并且地物覆盖价值较低的地区,包括游家店、下胡、大塘杨家和马山等处。研究成果可为中小河流防洪规划、避洪转移等提供参考依据。     

阳澄淀泖区动态洪水风险图的编制及其管理系统的开发

基于大量的实测和调研资料,建立了能反映阳澄淀泖区现状河网、圩区分布及水工建筑物调度的水动力模型,经率定和验证后能够用于该区域的洪水模拟。基于Web技术、GIS技术和数据库技术,研发了嵌套水动力模型的动态洪水风险图管理系统。针对任意降雨、边界条件、水工建筑物参数及调度参数,系统能快速调用模型进行模拟计算并生成动态洪水风险图。与在线预报数据结合,可实现洪水预报预警,为洪水风险图在防洪减灾、洪水管理、洪水预报等方面提供技术支撑和应用借鉴。     

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.     

Floodplain Management in Urban Developing Areas. Part II. GIS-Based Flood Analysis and Urban Growth Modelling

In Part I of this article the very dynamic nature of floodplain management was discussed and the need for modelling the urban growth processes and formulating scenarios of urban development was emphasised. In this second part, the use of Geographic Information Systems (GIS) for addressing those problems is presented. GIS have been recognised as a powerful means to integrate and analyse data from various sources in the context of comprehensive floodplain management. Adequate information and prediction capability is vital to evaluate alternative scenarios for flood mitigation policies and to improve decision making processes associated with flood management. A framework for the comprehensive evaluation of flood hazard management policies is also addressed in this article. This comprehensive approach to flood problems is more than an attitude or a philosophical starting point. It makes use of specific technological tools conceived to be used by different actors, some of them being nonexperts in flood analysis. These tools, based on GIS, are very appropriate for a participatory approach to flood policy formulation and floodplain management because they help communicating with the public in a scientifically correct and yet rather simple manner.     

Flood hazard assessment of Atrato River in Colombia

The flood hazard caused by Atrato River in Quibdó, northwest of Colombia is assessed using statistical modeling techniques (Gumbel and GRADEX), hydraulic modeling with HEC-RAS and the Geographic Information Systems (GIS). Three flood hazard maps for return periods of 10, 20 and 50 years are generated. The flood hazard modeling reveals that the flooded zone is more significant out of the left (West) bank than out of the right (East) bank of Atrato River. For the three return periods the maximum depth of water reached by the river and extent of flooding are estimated. Sensitivity analysis on roughness coefficient and peak discharge is performed. For 50 year return period (Q =3054 m³/s), water depth on the left and right bank of Atrato River is 3.7 m and 3.1 m, respectively. This information is useful in defining the minimum height of flood protection structures such as dikes to protect the area from flooding. The results can be useful for evacuation planning, estimation of damages and post flood recovery efforts.     

Flood inundation mapping using NOAA AVHRR data

The river Brahmputra flowing through the state of Assam (India) floods every year. The analysis of spatial extent and temporal pattern of flood-inundated areas is of prime importance for mitigation of floods. With the development of remote sensing techniques, flood mapping for large areas can be done easily. In case of flood affected area mapping of large area it will not be feasible to use high-resolution data, because the whole area will be covered in number of scenes. Therefore use of NOAA (National Oceaongraphic Atmospheric Administrative) data is quite useful in such type of studies. NOAA-AVHRR (Advanced Very High Resolution Radiometer) data have the potential for flood monitoring due to high frequency of global coverage, wide swath, high repetivity and low cost. In this study, NOAA-AVHRR data have been used for mapping of flood-affected area during the year 2003. On the basis of spectral characteristics of land and water, a methodology for water identification is presented. The maximum spatial extent of floods, generated by compiling the available cloud free maps, is informative about flood damages. Analysis of results reveals that in the months of July and August almost 25-30% of the area was flood affected. Also the result indicates that in some districts, the flood-affected area is very high.     

Floodplain Inundation Analysis Combined with Contingent Valuation: Implications for Sustainable Flood Risk Management

This study presents the results of open-ended contingent valuation method (CVM) to estimate the residents’ maximum willingness to pay (WTP) for flood insurance and structural flood control measures in the Neka River Basin in Northern Iran. Flood inundation analysis and floodplain risk mapping were conducted by applying the HEC-RAS model combined with GIS analysis. A calibrated 100-year flood risk inundation map was considered as a basis for this research. This paper demonstrates applicability of CVM combined with flood inundation analysis to understand public participation for flood risk management, and their perception of flooding, considering associated socioeconomic and environmental factors. The results have shown that stated WTPs significantly varies with household income, distance people live from the river and the land use type of properties. Findings of this study suggest that the majority of respondents view flood hazard as the most important natural disaster. Furthermore, WTPs are significantly higher for those who have high level of flood risk perception. Three policy options for flood risk management are discussed, which include flood zoning and land use regulation, flood insurance program, and structural measure of levee construction. The advantages and disadvantages of each option are explored. It was concluded that a combination of possible mitigation options should be considered in order to achieve sustainable flood risk management in the Neka River Floodplain.     

FLOOD INUNDATION MAPPING FOR INTEGRATED FLOODPLAIN MANAGEMENT: UPPER MISSISSIPPI RIVER SYSTEM

Natural hydrogeomorphic characteristics and hydrologic alterations are important ecological drivers, and hydrology is also a common ecological, flood control and navigation system indicator. Hydrologic characteristics change dramatically from one end of the Upper Mississippi River System to the other, and hydraulic characteristics also differ spatially across the river channels and floodplain in response to dams, levees and diversions. Low flow surface water spatial change in response to navigation and flood control has been well known for many years, but little information was available on the spatial distribution of frequent floods. The flow frequency data presented here were developed to better estimate contemporary floods after historic flooding in 1993. Flood stage estimates are enhanced in GIS to help quantify and map potential floodplain inundation for more than 1000 river miles on the Upper Mississippi and Illinois Rivers. Potential flood inundation is mapped for the 50% to 0.2% annual exceedance probability flood stage (i.e. 2‐ to 500‐year expected recurrence interval flood) and also for alternative floodplain management scenarios within the existing flood protection infrastructure. Our analysis documents: (i) impoundment effects, (ii) a hydrologic gradient within the navigation pools that creates repeating patterns of riverine, backwater and impounded aquatic habitat conditions, (iii) potential floodplain inundation patterns for over 2 million acres and (iv) several integrated floodplain management scenarios. Extreme flood events are more common in recent decades, and they are expected to continue to occur at greater frequency in response to climate change. Floodplain managers can use the results presented here to help optimize land management and flood damage reduction on the Upper Mississippi River System. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.     

宁夏防汛防凌三维电子沙盘系统建设

本文介绍了宁夏防汛防凌三维电子沙盘系统建设背景和需求,并在系统分析宁夏防汛防凌工 作的基础上,提出了该系统建设的框架体系和功能结构。在该系统建设中,利用地理信息系统、遥 感、海量数据管理、数据库等技术建立了宁夏回族自治区三维空间数字地图,再现了全区的三维地 形、地貌场景,在三维场景中实现了防洪防凌工程信息查询,汛情和凌情信息的实时监控与管理,为 宁夏防汛防凌工作提供了一个三维的基础数字化平台。     

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。     

基于GIS和遥感数据的洪水风险分析

随着城市化进程的不断深化,洪涝灾害已经成为威胁人类生存的一种主要自然灾害。人们逐步认识到,仅仅使用工程措施来防御洪水是远远不够的,非工程措施近年来已进入到防洪领域。管理洪水、分析洪水灾害是非工程措施的一个重要方面。应用GIS工具研究ASAR数据和DEM数据获取研究区域的水深信息。以东洞庭湖区域为研究对象,运用3种常用的插值方法（IDW、Kriging和Topo to Raster）进行水面插值．但这些方法的插值效果不是很好。一种新的插值方法（ADDM,基于平均距离插值方法）被用来进行水面插值。相互比较的结果表明,ADDM方法在水深精度和水面连续性方面都优于其他3种方法。最后,根据ADDM方法获取的水深信息和洪水频率图制作东洞庭湖区洪水风险图。     

基于GIS的避洪转移分析技术研究

为减少洪水溃堤造成的洪灾生命损失,快速高效组织人员撤离避险,详细介绍了避洪转移分析流程,探讨了GIS网络分析技术在避洪转移分析中的应用方法。该方法包括路网数据的拓扑检查与处理、路网数据集的建立、转移单元与安置点的合理配置、避险最优路径计算分析等。并以浑河右岸某段堤防溃堤为例,实现了避洪转移最短路径搜索,绘制避洪转移路线图。结果表明应用GIS技术可方便得出避险转移最优路径、提高转移效率、节约转移成本,绘制的避险转移图及方法等能为防洪应急预案的制定提供科学参考。