2002 年8 月欧洲特大洪水概述——兼议我国水灾应急管理体制的完善

2002年8月,德国、奥地利、捷克三国发生了百年未遇的特大洪水,涉及易北河与多瑙河两大流域。各国政府与民众奋起抗灾自救,及时启动了应急管理体系,大大减少了人员的伤亡。已有防洪工程体系经历了超标准洪水的严峻考验,水库及时应急泄洪,确保无一溃坝事故发生。蓄滞洪区适时运用,减轻了下游的防洪压力。由于河流洪水特性不同,经济发展水平不一,且受社会体制沿革变化的影响,各国处理重大危急事件的行动也各有特点。本文通过对比分析,提出完善我国水灾应急管理体系的建议。     

Prediction of the future flood severity in plain river network region based on numerical model: A case study

Suzhou is one of China's most developed regions, located in the eastern part of the Yangtze Delta. Due to its location and river features, it may at a high risk of flood under the climate change background in the future. In order to investigate the flood response to the extreme scenario in this region, 1-D hydrodynamic model with real-time operations of sluices and pumps is established. The rain-runoff processes of the urban and rural areas are simulated by two lumped hydrologic models, respectively. Indicators for a quantitative assessment of the flood severity in this region are proposed. The results indicate that the existing flood control system could prevent the Suzhou Downtown from inundation in the future. The difficulty of draining the Taihu Lake floods should be given attention to avoid the flood hazard. The modelling approach based on the in-bank model and the evaluation parameters could be effective for the flood severity estimation in the plain river network catchment. The insights from this study of the possible future extreme flood events may assist the policy making and the flood control planning.     

长江洪水特性及防洪对策探讨

长江洪水可分为全流域型大洪水和区域性大洪水两种类型，洪灾基本上由暴雨洪水形成，长江防洪对策有：确保重点，兼顾一般；正确处理江湖关系，做到江湖两利；合理处理蓄与泄的关系；协调处理干、支流关系；近期治理与远期规划相协调；实行防洪统一调度．     

Impacts of Projected Climate Changes on Streamflow and Sediment Transport for Three Snowmelt‐Dominated Rivers in the Interior Pacific Northwest

Anthropogenic climate change is likely to have significant impacts on river systems, particularly on rivers dominated by seasonal snowmelt. In addition to altering the timing and magnitude of streamflow, climate change can affect the energy available to transport sediment, as well as the availability of sediment to be transported. These hydrologic changes are sensitive to local climate, which is largely controlled by topography, but climate models cannot resolve processes at these scales. Here, I investigate impacts of climate change on streamflow and suspended‐sediment transport for three snowmelt‐dominated rivers in the interior Pacific Northwest – the Tucannon River in Washington and the South Fork Coeur d'Alene and Red rivers in Idaho – using downscaled climate simulations from regional climate models (a range of three models plus an ensemble average) to drive a basin‐scale hydrologic model. The results indicate that climate change is likely to amplify the annual cycle of river discharge, producing higher winter discharge (increases in ensemble mean January discharge ranging from 4.1% to 34.4% for the three rivers), an earlier spring snowmelt peak (by approximately one month), and lower summer discharge (decreases in ensemble mean July discharge ranging from 5.2% to 47.2%), relative to a late 20th‐century baseline. The magnitude of the largest simulated flood under the ensemble‐average climate change scenario increases by 0.6–41.6% across the three rivers. Simulated changes in suspended‐sediment transport generally follow the changes in streamflow. These changes in discharge and sediment transport will likely produce significant impacts on the study rivers, including changes in flooding, physical habitat, and river morphology. Copyright © 2014 John Wiley & Sons, Ltd.     

英国的洪水风险管理

为了减少洪水造成的破坏和损失，近年来世界各国的洪水管理已从单一的防洪工程向洪水风险管理转变。除了能进行有效的洪水防御外，洪水风险管理还被认为是维持生物多样性、河流及海岸生态系统的重要手段。回顾了英国的洪水风险管理及其组成体系，并分析讨论了未来可能面临的问题及应对措施。结果表明，随着全球气候变化及社会经济发展，洪水发生的频率及其影响正在增加。因此，如何全面综合考虑降雨、径流、河流、洪泛区以及人类活动、社会经济规划、发展和管理等诸多因素是实施洪水风险管理面临的重要课题。     

变化环境下洪涝风险演变特征与城市韧性提升策略

在全球气候变暖与快速城镇化的背景下，极端暴雨洪涝发生的可能性与不确定性在增大，同时洪涝威胁对象、致灾机理、成灾模式、损失构成与风险特性均在发生显著变化。本文基于郑州“7.20”特大暴雨水灾的实地调研与典型案例的剖析，阐述当代社会洪涝风险连锁性、突变性、传递性的演变机理与趋向，结合国际社会与水共存、韧性提升的理念与实践，探讨变化环境下与新时代基本国情相适宜的洪涝灾害防治策略。研究结果表明，应对快速城镇化进程中极端暴雨洪涝灾害，需以流域为单元做好综合治水的统筹规划；韧性城市只有建成不怕淹的城市，才有利于实现人水和谐的目标；在发展不均衡、不充分的现实条件下，完善与健全洪涝灾害风险管理与应急管理体制与运作机制，不仅在于保障安全，而且要为新时代经济社会快速平稳发展保驾护航。     

A customised approach to determining the geomorphic effectiveness of small flood events in a regulated river

The construction of dams significantly alters flow and sediment regimes with subsequent deleterious effects on the morphological and ecological character of rivers. Effective experimental floods can ameliorate the downstream geomorphic impacts of dams. The traditional view is that large floods are required to perform effective geomorphic work, and the geomorphic outcomes of small floods are often overlooked. Many river restoration frameworks do not consider small floods. Yet, there is evidence that the hydrological characteristics that ameliorate specific geomorphic impacts in a river are unique to each river, and a customised approach to setting the right mix of floods (including small experimental floods) is needed. In this study, we modify an existing flood effectiveness model developed for large floods, for determining the geomorphic effectiveness of small floods in a highly regulated Australian river. Two flood classes were added to the model (medium peak stream power and moderate total energy expenditure), and the flood power characteristics were rescaled to reflect the relative difference in the magnitude of the small floods and the magnitude of the geomorphic work performed. Using a step‐wise approach, this customised model determined the geomorphic effectiveness of small floods. The best flood for ameliorating the geomorphic impacts of flow regulation had medium to long duration (10 to 51 days), high peak unit stream power (77 to 123 Wm^?2) and moderate to large total energy expenditure (78,600 to 342,320 × 10³ J). This approach to determining flood effectiveness for small floods is applicable to other geomorphically impacted river channels downstream of dams and can be used to inform experimental flood releases for geomorphic outcomes.     

复杂河网地区气候-水文-水动力耦合模型模拟

以淮河流域中下游结合部的洪泽湖周边滞洪区为研究对象,基于紧耦合技术,将一维和二维水动力模型进行耦合,基于松耦合技术,将气候模型与水文模型、水文模型与水动力模型进行耦合,实现了流域、河网、蓄滞洪区和湖泊复杂系统气候-水文-水动力单向耦合,并对气候变化影响下的复杂河网地区水流演进进行了模拟。结果表明:构建的气候-水文-水动力耦合模型对洪泽湖周边滞洪区洪水演进具有较好的模拟能力和适应性;气候变化导致未来淮河流域洪水量级增加,加大了洪泽湖周边滞洪区的洪水风险。     

Flood Hydrology and Geomorphology of Monsoon-dominated Rivers: The Indian Peninsula

ABSTRACT

The rivers of the southern part of the Indian Peninsula are monsoonal in nature and the hydrological characteristics of these rivers djffer markedly from those of Himalayan rivers. The rivers are subjected to severe floods during the monsoon season. In the last few decades, several large-magnitude floods (peak floods between 10,000 and 80,000 m³/s) have been recorded. In general, floods caused by precipitation from Bay of Bengal depressions include the peak flood of record. Analyses of the systematic, historical, and paleoflood records indicate that, in recent decades, the frequency of high-magnitude floods has increased significantly. Hydraulic estimates reveal that high flows are capable of bedrock erosion and transportation of coarse material.

Such large floods are important, not only from the standpoint of geomorphic work, but also in terms of social impact. Floods in the peninsular region are responsible for colossal loss of human life, crops, and property. In recent years, various measures offlood control and management have been adopted. However, flooding in such large rivers profoundly challenges flood-hazard management, because of the inadequacy of conventional data and high spatio-temporal variability of floods. To understand flood hazards and environmental change it is imperative that engineers and hydrologists utilize historical and paleoflood records to improve risk analyses as well as to estimate probable maximum flood on rivers such as these in a highly flood-prone region.     

淮河流域未来情景描绘

淮河流域位于我国气候过渡带,是"大雨大灾、小雨小灾、无雨旱灾"的洪、涝、旱灾害频繁发生的地区.在分析现有防洪减灾策略存在的不足基础上,提出了以流域为单元的国土综合整治防洪策略,协调人口和经济发展与流域资源、环境、生态承载力之间的关系,提出了蓄滞洪区功能调整和产业结构调整的具体措施,以及新的管理思路,描绘了处于困境的淮河流域和蓄滞洪区发展的未来情景.     

基于MIKE FLOOD模型的西北城市河道橡胶坝群洪水风险分析研究

由于西北城市河道比降大,暴雨和山洪形成河道洪水突发性强,河道橡胶坝群的修建改善了城市生态环境,同时也客观上增大了城市洪水风险.基于MIKE FLOOD水动力学模型,对西北城市橡胶坝群河道典型案例进行了一二维耦合水动力学模型计算,研究了在河道遭遇大洪水时橡胶坝群未塌坝运行的洪水动态演进情况,定量计算了对城市可能造成的淹没情况以及洪灾损失,指明了橡胶坝群未按照防汛预案采取度汛措施而造成的潜在洪水风险,并且提出了降低城市河道橡胶坝群洪水风险的建设管理措施.     

三峡工程对洞庭湖典型洪水的防洪作用分析

根据三峡工程建成后对荆江和城陵矶地区补偿的调度方式,采用大湖演算模型对1996、1998、1999年洞庭湖区3种不同来水组合的典型洪水进行了分析计算.计算结果表明,三峡工程不同的实时调度方案,其作用相差大,且对于不同的来水组合类型的洪水,不同的调度方式其作用大小不一样,对于历时不长,长江干流洪水与湖南省"四水"恶劣遭遇的湖区洪水,作用较大;对于湖南省"四水"来水为主的典型洪水和长江干流与"四水"长历时复峰恶劣遭遇的湖区洪水其作用较小.     

Recent Flood Control Measures for Urban Rivers in Japan: Case Study of the Kanda River in Tokyo

ABSTRACT

Recently, floods occurred frequently almost everywhere in urban areas in Japan. These urban disasters became an important social problem. In the present study, we investigated floods on the Kanda River in Tokyo. The history of flooded areas, and flood control projects in progress, involving river improvements, expansion of sewerage projects, and urbanization, are reviewed. We also have presented our recent survey results for the flood of August 27, 1993 that occurred in the Kanda River Basin. Hydraulic and hydrologic impacts of historical floods are also given, including an investigation of the economic and social impacts. In urban areas, it is difficult to increase the width of the river. Thus, river improvement works essentially consist of the use of underground diversion channels. In Tokyo, Takadanobaba, Edogawabashi, and Suidobashi diversion channels have been completed. Regulating reservoirs along these rivercourses have been constructed in the Myoshoji River Basin and Zenpukuji River Basin. It is quite difficult to buy land along river courses in Japan. An interesting decision was recently made about the 75mm Plan, which introduces a new method for an underground river; the so-called Tokyo Loop 7. The underground river consists of a pipe having a diameter of 10.0–12.5 m. Loop 7 starts from the upstream section of the Shirako River; and draws flood water from ten different rivers, including the Myoshoji, Zenpukuji, and Kanda rivers. The total length of the pipe is 30 km. The flood water through Loop 7 is pumped out to Tokyo Bay.     

Evaluation of Vulnerability to Extreme Climatic Events in the Brazilian Amazonia: Methodological Proposal to the Rio Acre Basin

The southern border of the Brazilian Amazon is one of the most sensitive areas to deforestation in Brazil. In addition to problems related to changes in land use, new issues are emerging, including climate change and its negative effects on the regional hydrological cycle. In recent years considerable research has been undertaken focusing on climate change and its effects on Amazon Biodiversity, carbon cycle, fire incidence and even on regional water resources, but there is very little research linking territorial planning and public policies to prospective planning scenarios and climate change and the necessary adaptation or mitigation actions to address climate vulnerability. This study examines issues pertaining to social, economic and environmental vulnerability, including new challenges posed by climate change. Examples of environmental problems related to climate dynamics of the Rio Acre Basin are floods and dry periods such as the major drought of 2005 and the 2009 flood. The use of methodology for integrated assessment of vulnerability to river basins in Amazon Region constitutes a valuable instrument for territorial planning, since it takes into account both the challenges of poverty and the environmental fragility, as well the possible aggravations of extreme climatic events in the future.     

Bio-geomorphic alteration through shifting flow regime in a modified monsoonal river system in Korea

River processes and patterns are affected by changes in the watershed driven by natural and human-induced causes. A sudden pattern alteration from a “white river” (bare soils) to a “green river” (vegetated) influences riverine biodiversity and can increase flood risk. Despite these significant impacts, knowledge on the triggers that kickstart feedback exacerbating changes in bio-geomorphic patterns is insufficient. In this study, we collected and analyzed detailed monitoring data on a sandy, hydro-morphologically active, and monsoon-driven river in Korea. The surface area covered by vegetation has been increasing; this increase intensified after the 2014–2015 drought, which provided a window of opportunity for vegetation establishment. During the drought, pioneer vegetation densely colonized bare sandbars and temporarily exposed riverbed. Despite partial rejuvenation by several subsequent floods, succession to woody vegetation occurred, resulting in a stable vegetation cover. Narrowing and incision of a low-water channel occurred, and secondary channels formed inside the floodplain. The results of this study show a rapid bio-geomorphic alteration triggered by the shifts in flow regime in a river primed by human-induced changes. Furthermore, modified monsoon-driven rivers might be on the brink of similar bio-physical alterations triggered through shifting flow regime following climate change, leading to increased flood risk and impacts on endemic biodiversity.     

玛纳斯河流域防洪现状及工作建议与对策

玛纳斯河流域自1994年以来相继发生洪水灾害,由于上游缺乏骨干防洪控制性工程,堤防工程数量较少、标准低,洪水灾害频发,严重制约了该流域社会经济的可持续发展。在制定防洪规划、建设大型防洪控制性工程、加快做好重点中小河流治理和山洪灾害防治及保护河道安全行洪等方面,提出了建议和对策。     

Hydrological changes and river regulation in the UK

Water levels of streams and rivers in the United Kingdom have been regulated by weirs for more than one thousand years, but regulation of the flow regime by impoundments began in the latter half on the 19th Century. Organized river flow measurements were not undertaken until 1935, and today the average record length is about 20 years. Only three gauging stations have provided data suitable for pre- and post-impoundment comparisons. Other studies have relied on the comparison of regulated and naturalized discharges. In either case climate and land-use changes make evaluation of the hydrological effect of impoundments problematic. This paper reviews research on hydrological changes due to river regulation in the UK, and presents a case study of the River Severn to evaluate the influence of Clywedog Reservoir on flood magnitude and frequency. Consequent upon dam completion, on average, median flows have been reduced by about 50per cent; mean annual floods have been reduced by about 30per cent; and low flows have been maintained at about 22 per cent higher than the natural Q₉₅ discharge. However, marked differences exist between rivers. The direct effect of reservoir compensation flows and the indirect effect of inter basin transfers for supply have significantly increased minimum flows in most rivers, although in the case of the latter this involves the discharge of treated effluents. In contrast, the effects of impoundments on flood magnitude and frequency is less clear and on the River Severn, at least, changes in flood hydrology during the past two decades are shown to be more related to climate change than to river regulation.     

River regulation in Southern China: Ecological implications,conservation and environmental management

Southern China—i.e. China south of the Chang Jiang (Yangtze River)—has a monsoon climate with pronounced wet and dry seasons and consequent effects on river discharge. There is considerable inter-year variation in the duration and intensity of the monsoon, and the region experiences frequent floods and droughts which cause considerable human misery. The importance of floods as an incentive for river regulation is apparent from the fact that 10% of China's area, inhabited by 65% of the population and responsible for 70% of the agricultural and industrial output, is below the flood level of major rivers. Irrigation and hydroelectric power are additional benefits to be derived from river regulation. China has a 4000 year history of river regulation, but most of the changes that have been made to riverine environments have not taken account of the ecological consequences. This review considers the ecological implications of planned or existing schemes for the regulation of southern Chinese rivers. Particular attention is paid to the Chang Jiang and Zhujiang (Pearl River) which, by volume of discharge, are the two largest rivers in China. Large-scale water-transfer projects and the planned construction of the biggest dam in the world (the Three Gorges High Dam) on the Chang Jiang have the potential to affect fisheries stocks and endangered fish species, to alter inundation patterns in wetlands of international conservation significance and may contribute to the extinction of the endemic and highly endangered Chinese alligator (Alligator sinensis) and Chinese river dolphin (Lipotes vexillifer). In addition, deforestation and soil erosion in the Chang Jiang basin have given rise to siltation and degradation of floodplain habitats. In the Zhujiang, dam construction has caused reductions in fisheries stocks but here, as elsewhere in China, the ecologically damaging consequences of river regulation are exacerbated by overfishing and increasing pollution of rivers by sewage, pesticides and industrial wastes.     

大避暑山庄水战略市区旱河生态水网建设探讨

旱河是承德山城重要的泄洪水道,有雨行洪,无雨干涸.目前市区多条旱河河道干涸,棚盖建筑严重,河道景观、生态、服务功能不能发挥.该文通过探讨旱河河道断面进行优化,结合河流生态学原理,提出了营造旱河生态水网,因河制宜,一河一策,一河一景方案的必要性.     

Impact of regulated releases on periphyton and macroinvertebrate communities: The dynamic relationship between hydrology and geomorphology in frequently flooded rivers.

Flood‐type disturbances affect both periphyton and macroinvertebrate communities depending on their frequency, magnitude and duration, but some impacts can be mitigated by geomorphic constraints. We studied four rivers in the Adirondack Mountains; the Indian River experienced regulated flow releases creating bank‐full floods four times/week whereas other study sites provided a continuum of control conditions for comparison. We sampled periphyton and macroinvertebrate communities in each river along with channel hydrology, hydraulics and geomorphology. Periphyton abundance varied seasonally and among rivers depending on nitrate concentrations and scour. Flow releases created a static mosaic of patches consisting of heavily scoured bed sediment in the thalweg (high shear stress areas—HSS) which had very low periphyton abundance; boulders and rocky shoals created low shear stress areas (LSS) supporting mats of filamentous algae. Macroinvertebrate densities were highest in HSS areas whereas LSS areas had lower macroinvertebrate densities that were more similar to reference rivers, although both LSS and HSS areas had the lowest species diversity and richness. Macroinvertebrate composition in HSS areas was dominated by filter‐feeders, whereas LSS areas had more gatherers and scrapers. While all rivers had high boulder densities, the Indian River could be considered geomorphically moribund—its substrate was immobile and the channel experienced no adjustments in spite of high flood frequencies. These physical characteristics help mitigate the severe hydrologic conditions that releases create because the static mosaic of low and HSS patches allow certain macroinvertebrates adapted to this level of disturbance to persist. This static mosaic is different from the shifting mosaic pattern often observed in streams following flood‐type disturbances. Geomorphically moribund rivers may lack ecological sensitivity to hydrologic disturbances, and decisions to limit flow modification (e.g. recreational flow releases, hydropower generation) should consider whether assumed ecological impacts are likely to occur given local geomorphic conditions and constraints. Copyright © 2010 John Wiley & Sons, Ltd.