Spatial diversion and coordination of flood water for an urban flood control project in Suzhou, China

Suzhou City,located in the Yangtze River Delta in China,is prone to flooding due to a complex combination of natural factors,including its monsoon climate,low elevation,and tidally influenced position,as well as intensive human activities.The Large Encirclement Flood Control Project(LEFCP)was launched to cope with serious floods in the urban area.This project changed the spatiotemporal pattern of flood processes and caused spatial diversion of floods from the urban area to the outskirts of the city.Therefore,this study developed a distributed flood simulation model in order to understand this transition of flood processes.The results revealed that the LEFCP effectively protected the urban areas from floods,but the present scheduling schemes resulted in the spatial diversion of floods to the outskirts of the city.With rainstorm frequencies of 10.0%to 0.5%,the water level differences between two representative water level stations(Miduqiao(MDQ)and Fengqiao(FQ))located inside and outside the LEFCP area,ranged from 0.75 m to 0.24 m and from 1.80 m to 1.58 m,respectively.In addition,the flood safety margin at MDQ and the duration with the water level exceeding the warning water level at FQ ranged from 0.95 m to 0.43 m and from 4 h to 22 h,respectively.Rational scheduling schemes for the hydraulic facilities of the LEFCP in extreme precipitation cases were developed ac-cording to food simulations under seven scheduling scenarios.This helps to regulate the spatial flood diversion caused by the LEFCP during extreme precipitation.

Urban flood control strategy based on new relationship of human and flood

China is one of the countries with the most serious flooding disasters.In China,above 70% of big cities,50% of population and 75% of industrial and agricultural output value are distributed in eastern coastal areas with serious flooding.Therefore,enhancement of theoretical study and experience summarization of urban flood control is of great theoretical and practical significance.As economy is developing rapidly,urban scale is expanding fast,and urban flood control stand is promoted.Urban flood control calls for new concept and methods.This paper makes a systematic summarization of concept evolution and advanced methods concerning urban flood control at home and abroad.The concept of urban flood control has transformed from simple flood control and drainage to coexistence with and use of flood.Flood control measures have transferred form emphasis upon engineering ones to priority to both engineering and non-engineering ones,with special attention to ecological flood control,such as making full use of ecological revetment,ecological realignment of a river,multi-objective management of urban flood detention region,turning flood into resources and utilization of wetlands.

Methodological Proposition of an Integrated System for Urban Floods Control

In the State of Santa Catarina, Brazil, especially in the Itajai valley, there are records of accidents and disasters mainly associated to landslides and floods, which have caused significant damages and losses, including human lives. In order to make the coexistence with such natural disasters possible, most particularly with floods, a integration is required among the technical, political, environmental, and human knowledge. Measures that encompass integrated actions for the entire river basin, with the help from an updated technical cadastre and tools, such as the GIS, allow the development of planning tools that might effectively help the people to live with the water, or else to cope with floods in a more appropriate manner. This paper attempts to propose a methodology for urban flood control, based on the integration among the several public entities involved in the flood control, along with the CTM （Multipurpose Technical Cadastre） and GIS tool. In order to solve or minimize the problems, the model proposed here aims at promoting a balance between the agents involved, and enables to rank the degrees of importance assigned to the different needs, thus allowing to eliminate or to improve those areas and processes that are duplicated or superimposed.

Improvement Strategies of Flood Control Landscape in Suburban Villages and Towns from the Perspective of Aquaphilia and Livability

In the context of urban and rural integrated development, many suburban villages and towns are still threatened by both urbanization and natural disasters. In order to explore the improvement strategies of flood control landscape integrating water ecology, water safety, water culture and water landscape, the Luozhou Ancient Town by the Wulong River in Fuzhou City was taken as an example, and the concept of pluralistic symbiosis from the perspective of aquaphilia and livability was proposed through field investigation, data monitoring, site analysis and planning, that is, while retaining the positive attributes of “boundary”, its negative limitation of “pluralistic” space is broken, so as to establish a pluralistic and symbiotic environment with aquaphilia and livability. It can not only effectively alleviate the contradictions between urban and rural areas, between water and land, and between old and new cultures, but also activate the vitality of suburban villages and towns, providing a new idea for the improvement of flood control landscape.

From risk control to resilience: developments and trends of urban roads designed as surface flood passages to cope with extreme storms

Urban roads can be designated as surface flood passages to transport excess runoff during extreme storms, thereby preventing local flooding, which is known as the major drainage system. However, this practice poses significant risks, including human loss and property damage, due to the high flow rate and velocity carried by roads. Moreover, urban roads with low flood-resilience may significantly hamper the transportation function during severe storms, leading to dysfunction of the city. Therefore, there is an urgent need to transform risk-oriented flood passages into resilient urban road-based flood passages. This paper presents a systematic review of existing methodologies in designing a road network-based flood passage system, along with the discussion of new technologies to enhance system resilience. The study also addresses current knowledge gaps and future directions. The results indicate that flood management measures based on the urban road network should integrate accessibility assessment, lifeline and emergency planning to ensure human well-being outcomes. Furthermore, the special needs and features of vulnerable groups must be taken into serious consideration during the planning stage. In addition, a data-driven approach is recommended to facilitate real-time management and evaluate future works.

Effect of Flood Peak Discharge Control by a Small Reservoir in an Urbanized Area—Case Study in the Kurabe River Basin, Japan

Recently severe damage of flooding by urbanization was frequently occurred. To prevent this damage, small reservoir was constructed in the urbanized residential area. This paper describes an effect of flood peak discharge control by a small reservoir (control reservoir) caused by rapidly developed urbanization. Although work for this purpose was conducted, research on the effects of the control reservoir was not conducted until now. This research, conducted by simulation, was a case study in the Kurabe River Basin in the Tedori River Alluvial Fan Area, Japan, based on the precise investigation of the reservoir in the actual field. The study was conducted to determine not only the actual control reservoir capacity for the newly developed residential area but also the ideal capacity for all present residential areas and the largest capacity allowable for a maximum rainfall event that recently occurred. The control reservoir effects between individual blocks and the entire basin area were compared by dividing the test basin into 15 blocks (sub-basins). The results showed that the effects on the capacity per unit area of the residential area in blocks have close relationship with the decreasing ratio of peak discharge in blocks. Consequently, the effects of control reservoir capacity and the limitation were clarified. In the future, control reservoirs should be constructed for all of the already developed residential areas, for example, by utilizing underground car parking lot. The results of this research can contribute to the design of the control reservoir for protection against flooding damage in urbanized areas.

Characteristics of Rainstorm and Flood Disaster in Shaoyang City and Flood Protection Countermeasures

Based on ground meteorological observation data at 10 representative stations of Shaoyang City during 1951-2017 and rainfall data at over 220 automatic weather stations during 2005-2017,statistical analysis on rainstorm and flood disaster in Shaoyang was conducted. Occurrence characteristics and rule of rainstorm and flood disaster were found,and disaster situation was evaluated and analyzed. The results showed that（ 1）there was almost local rainstorm and flood in Shaoyang City every year,with strong seasonal characteristic.（ 2） The loss caused by rainstorm and flood disaster was the most serious in various meteorological disasters.（ 3） Rainstorm and flood disaster generally had the sudden and devastating characteristics. Via the analysis and research on rainstorm and flood disaster,defense measure and countermeasure of rainstorm and flood were proposed,which could provide scientific decision basis for party and government leading flood relief,and had important guidance significance for preventing and mitigating disasters by government agencies.

城市洪涝治理与韧性城市建设:变革、创新与启示

我国城市洪涝治理经历了从工程措施到工程与非工程措施并举,从洪涝分治到洪涝统筹,从城市局部治理到流域系统治理的重大转变。特别是海绵城市和韧性城市理念的引入,显著提升了城市洪涝治理水平,促进了城市可持续发展。经过多年探索与实践,我国在技术应用、政策管理、公众与社会参与等方面取得了显著进展,城市洪涝模拟与风险评估取得重要成果,监测感知系统日趋完善,预报预警技术取得突破,应用场景更加广泛;跨部门协作与联动机制、政府与社会资本合作模式的提出,高效信息传播机制和公众参与程度的加强,均显著增强了城市应对洪涝灾害的能力,为防洪减灾工作提供了有力支撑。借助北斗卫星、激光雷达、物联网、人工智能、大数据等先进技术,我国持续推进数字孪生流域、国家水网与区域水网建设,为洪涝治理和水利高质量发展提供了重要支撑。今后,城市洪涝治理将继续朝着系统化、智能化、生态化方向发展,面对新时代的机遇与挑战,应结合海绵城市与韧性城市建设,坚持系统治理、坚守底线思维、坚持创新发展,通过全局性谋划和整体性推动,不断提升水旱灾害防御水平和水安全保障能力。

沿江城市降雨特性及雨洪关系分析——以四川泸州市为例

沿江城市气候多变,外洪和内涝之间关系复杂,相互影响、相互制约,洪涝统筹是沿江城市面临的最主要问题。分析掌握沿江城市的暴雨、洪水特征,可提前预测不同降雨条件下河道洪水的特性及其对城区排涝的影响,对于城市防洪系统和排涝系统统筹兼顾、合理规划、洪涝预报预警,都具有重要意义。以四川泸州市为例,对暴雨时空分布特征、洪水特征规律等进行了分析探讨,以期为新形势下沿江城市防洪减灾体系建设提供参考。

系统治理理念下东引运河防洪排涝工程体系研究

以系统治理理念为指导,采用河网一维水动力模型和水动力水质耦合模型,对东莞市东引运河进行水文水力计算和水质模拟,提出了考虑供水、国考断面水质保护因素的防洪排涝工程体系为13.5 km河道实施清淤疏浚,2.4 km河道拓宽至50 m,新建分洪闸(总净宽30 m,设计流量299 m^(3)/s),新建两岸堤防(护岸)工程23 km,新建虎门泵站(设计流量70 m^(3)/s),如此可将东引运河防洪标准提高至50年一遇。通过关闭沿线水闸,上游来水全部从虎门水闸、泵站排出的调度方式,可保证泗盛国考断面水质达到Ⅲ类考核目标。所提方案可达到洪、潮、涝、污协同共治的效果,可供当地水务部门决策和类似工程设计参考。

城市曲面应急防洪屏结构优化研究

研发新型防洪抢险装备,对于防御城市洪涝灾害,保障城市生命线安全具有重要的意义。采用数值仿真模拟的方法,分析了城市曲面应急防洪屏(以下简称“防洪屏”)曲面拱度对结构受力特性的影响,进一步对防洪屏的结构体型进行了优化研究。结果表明:在同一挡水工况下,随着曲面拱度的增大,防洪屏在同一挡水条件下,所承受的应力逐渐减小,变形明显改善;根据计算结果提出了优化方案,优化的新体型防洪屏在水深小于0.8 m,流速小于1.0 m/s挡水工况下,结构最大应力小于材料特性指标安全极限阈值,满足挡水安全稳定要求,可以作为定型装备推广应用。研究成果为城市曲面应急防洪屏的优化设计提供了重要参考依据。

基于GIS和SWMM的西安市北郊片区排涝模拟与排水系统优化

为解决西安市北郊河道超载风险问题,通过SWMM和GIS技术构建管网-泵站-河道耦合模型,在不同设计降雨重现期(1、2、5、10、20、50年)下对该区域排水系统进行模拟,进而分析下游河道水位变化规律并提出雨水分流调配与调整泵站调度的协同优化措施。结果显示:在5、10、20和50年降雨重现期下,随着降雨峰值的到达,整个系统88%的排口都存在顶托现象,最长持续时间160min。在重现期为1、2、5和10年降雨条件下,协同优化的措施使得河道峰值流量分别下降了17.6%、4.9%、3.7%和2.6%,河道水位平均下降了35cm,排水系统的超载节点分别减少了16.7%、31.4%、34.2%和27.5%,超载管段的数量分别减少了25.0%、28.6%、30.8%和25.3%。

下沉式地铁车辆基地防洪排涝设计标准研究

[目的]下沉式地铁车辆基地是一种特殊空间利用形式的车辆基地,在防洪排涝方面存在较大风险,但国内现有相关规范和标准中尚无针对这方面的规定。因此,需对下沉式车辆基地防洪排涝设计能力进行深入研究,明确规范和标准中的相关内容,为此类项目建设提供设计依据。[方法]以宁波地铁5号线前殷停车场工程为例,分析了现有规范和标准中有关防洪和排水的设计要求,分析了下沉车辆基地的防洪涝设计方案,分别按50年和100年暴雨重现期对下沉基坑内不同区域防洪涝设计方案进行了对比分析。[结果及结论]下沉式车辆基地应采用“可靠的防、排内涝水措施”来满足防洪排涝的基本要求。在防洪涝方面,下沉式车辆基地防洪墙顶高程和出入口路面高程应高于百年洪水位+安全高,同时防洪墙与周边地面的高差应高于100年暴雨重现期下的所在地块内涝水位。在排涝方面,下沉基坑内的盖体屋面区域排水宜遵循“高水高排”的原则,按100年暴雨重现期设计屋面排水能力,通过重力流方式直排至基坑外;坑内敞开区域采用抽排方式,按100年暴雨重现期设计雨水泵站的总排水能力。

基于高分子材质的L型城市应急防洪屏受力分析

国内关于高分子材质城市内涝应急防御装备的研究较为少见。采用水槽试验与流固耦合数值仿真相结合的方法,对城市应急防洪屏(以下简称“防洪屏”)的结构受力特性展开研究。结果表明,数值仿真模拟与试验结果吻合较好。随着水深和流速的增大,防洪屏的应力和变形逐渐增大,最大应力位于防洪屏的踵部,最大变形位于挡水面顶部两侧。防洪屏的结构受力系数随着来流弗劳德数的增大快速衰减,当弗劳德数大于0.15后,结构受力系数趋于定值;相对于惯性力,防洪屏承受最大应力的影响因素主要是重力。研究结果可为防洪屏的进一步优化设计提供参考。

稻田控制排水对高邮灌区河道洪水过程的影响

以高邮灌区为例,采用水文-水动力模型,研究稻田控制排水措施对河道洪峰流量、水位和洪水过程的影响。结果表明,雨前通过控制灌溉适当降低田间水位可减轻稻田出流峰值,随着稻田控制水位的增加,稻田径流峰值逐渐降低。通过稻田控制排水,可降低田间出口峰值流量,改变灌区河道洪水过程,降低河道洪峰流量和水位,减轻灌区内部以及附近河道的防洪压力。

Design and evaluation of control strategies in urban drainage systems in Kunming city

Real time control （RTC） of urban drainage systems （UDSs） is an important measure to reduce combined sewer overflow （CSO） and urban flooding, helping achieve the aims of ＂Sponge City＇. Application of RTC requires three main steps： strategy design, simulation-based evaluation and field test. But many of published RTC studies are system-specific, lacking discussions on how to design a strategy step by step. In addition, the existing studies are prone to use hydrologic model to evaluated strategics, but a more precise and dynamic insight into strategy performance is needed. To fill these knowledge gaps, based on a case UDS in Kunming city, a studio on RTC strategy design and Management Model （SWMM） - uncier four typical rainfall events characterized by different return periods （1-year or 0.5 year） and different spatial distributions （uniform or uneven）. The equal filling strategy outperformss other two strategies and it can achieve 10% more CSO reduction and 5% more flooding reduction relative to the no-tank case.

基于MIKE FLOOD耦合模型的城市内涝模拟

基于MIKE FLOOD平台,将MIKE URBAN和MIKE 21模型耦合,建立城市内涝模型,对湖南省新化县典型区域的排涝情景进行模拟,结果表明该模型适用于城市内涝风险评估管理。评价结果表明,新化县目前建成的城市管网仍存在部分不合理的管段,水量难以立即排入资江或花山渔场,使老城区的整体排水能力受限,部分区域达不到设计规划的排水标准;城内主要的调蓄湖泊及暗渠均能满足20年一遇的设计标准;虽然现有的泵站系统能满足排水的需要,但区域内的5处易涝点仍需要采用对应的处理方案。

基于城市排水过程的内涝高效模拟方法

从实际城市排水过程的角度出发,提出了基于汇水单元概念的城市内涝高效模拟方法.该方法以雨篦子作为出水口来划分汇水单元,进而计算城市地表产汇流、积水深度及分布.同时,引入了当量宽度的概念,实现了明渠与有压流2种状态下管道流量和水位计算方法的统一.基于水量平衡原理,利用雨篦子耦合城市地表与地下管网,并结合孔口耦合管道与河道,构建了地表-管道-河道一体化的求解矩阵.本文将所提出的模拟方法植入成熟的太湖流域模型,并应用常州市城市产汇流与内涝试验基地的监测数据,对该方法的有效性和模型的可靠性进行了评估,以期为城市内涝模拟提供新思路.

田-沟-塘系统纳洪减污效应研究进展

针对南方地区水资源时空分布不均、水旱灾害频发且极端气候加剧、农业用水效率不高且面源污染严重等水安全问题,探讨稻田、排水沟、塘堰组成的灌溉排水系统(简称田-沟-塘系统)的调蓄纳洪、协同减污效应,以期为灌区雨洪调蓄和节水减排提供理论参考。从灌区雨洪调蓄实际出发,对当前田-沟-塘系统的国内外研究工作和发展进行总结,对田-沟-塘系统承纳洪水、输水蓄水、优化调水、协同防控氮磷流失等基础理论和关键技术等问题进行阐述,提出了田-沟-塘系统的“虚拟水库”模式及其纳洪效应的模型模拟方法。目前关于田-沟-塘系统调水控水的研究还普遍停留在净化水质单方面效用上,水量调蓄方面则多以研究稻田、排水沟、塘堰单个体的水平衡过程为主,缺少田-沟-塘系统联合调度的系统研究,如何提高灌区粮食生产过程中雨洪调蓄利用仍缺乏系统思维和技术手段。未来的研究要进一步拓展和丰富田-沟-塘系统雨水调蓄利用和协同减污功能,揭示稻田作为“隐形蓄水池”的蓄水潜力以及田-沟-塘系统的调洪削峰减污能力。

基于MIKE URBAN的西安市中心城区雨洪过程模拟

城市排水管网的分布与建设是城市基础设施建设的重要组成部分,城市的排水能力关系到城市服务功能的正常运转。通过城市雨洪过程的分析,可以评价城市洪涝灾害。以西安市中心城区为研究对象,利用MIKE URBAN构建排水管网模型,根据模拟结果对研究区管网排水能力进行评估,分析易涝成因。结果表明:MIKE URBAN能够较好地模拟城市管网水位、流量变化及易涝点的分布情况。根据西安市暴雨强度公式,设计不同重现期(1、2、3、5a)的降雨过程,在1a降雨过程下,研究区90%以上管道处于满流状态,60%以上的检查井发生溢流,满流管段数和溢流井个数会随着降雨频率的增加而增加,但增幅相对减少;管道设计标准普遍偏低、下垫面不透水率增大、地形等因素是导致地面积水的主要原因。研究成果可为城市内涝防治及海绵城市建设提供理论基础和技术支撑。