基于 SWMM 的张家港市排水防涝风险评估

在城市内涝频发的背景下,对城市地区的排水防涝风险进行正确评估至关重要。构建了张家港城市排水防涝SWMM模型。根据排水系统与排涝系统的不同需求,推求出适用于城市排水防涝系统的综合设计雨型,将此设计雨型作为上边界输入模型中,绘制了5年一遇、10年一遇和20年一遇的内涝积水深度和积水时间图。运用指标体系法,根据内涝积水深度、积水时间和所在地敏感性定义了排水防涝风险级别,绘制了不同重现期的内涝风险图并分析了易涝原因。结果显示,张家港市大部分地区是内涝产生的低风险区;人员密集的老城市产生涝灾的风险较大;随着暴雨重现期的不断增大,张家港市内受灾范围不断加大,受灾等级也不断提高。为其他城市进行排水防涝风险的评估、完善排水防涝体系提供思路。     

城市下垫面空间格局对社区尺度内涝过程的影响模拟

为研究城市下垫面空间格局对社区尺度内涝过程的影响, 构建社区尺度下的8种不同城市下垫面空间格局, 并建立相应的城市内涝数值模型, 模拟6种不同重现期(2 a, 5 a, 10 a, 20 a, 50 a, 100 a)设计降雨条件下内涝过程; 基于不同下垫面和降雨情景下的内涝数值模拟结果, 分别从内涝淹没特征值、时空变化过程、水动力特性等方面开展分析。结果表明: ①城市下垫面空间格局对社区尺度内涝淹没特征值、淹没时空变化过程和内涝积水流速分布均有一定影响; ②设计降雨重现期为2 a、5 a、50 a和100 a时, 不同城市下垫面空间格局间的积水总量峰值、积水面积峰值、区域最大积水深差别显著, 重现期为10 a和20 a时, 无明显差别; ③内涝积水较大流速分布主要集中在道路交汇处, 在本研究构建的情景中, 最大流速的差值占比为31.9%;④在8种不同城市下垫面空间格局中, 环形放射型格局在应对内涝方面更具弹性。本研究可为城市下垫面空间管控和城市内涝形成机理研究提供科学参考。     

基于动态聚类分析和模糊模式识别法的北京城区汛期降雨时空分布规律研究

以北京城区近十几年汛期50场暴雨过程为样本,利用动态聚类分析和模糊模式识别方法对单站雨型和降雨整体空间分布特征进行了研究,得到北京城区汛期最容易发生的雨型以及时空分布规律。结果表明,北京城区汛期主要发生前单峰型雨,峰值集中且极值雨量大,容易造成内涝积水。发生双峰型雨的次数较少,且极值雨量较小,对内涝积水影响相对较小。     

基于暴雨衰减特性的上海市长历时综合暴雨公式

编制适用于不同历时的综合暴雨公式是协调城市管网排水与区域防洪治涝的重要基础。选用上海市代表雨量站徐家汇站65 a实测雨量资料,建立不同重现期暴雨强度与历时关系,解析暴雨衰减规律,编制单一重现期暴雨公式,结合雨力公式推求适用不同重现期的长历时综合暴雨公式,并推导出暴雨重现期公式。结果表明:不同重现期1~24 h历时暴雨强度均以0.74的衰减指数衰减,据此推求的长历时综合暴雨公式可计算1~24 h任意历时、2~100 a任意重现期的设计暴雨,且平均相对和平均绝对均方根误差分别为1.9%和0.009 mm/min,符合规范要求;暴雨重现期公式可估算1~24 h历时内任意场次暴雨的重现期,高效地服务于城市洪涝防治决策。成果已纳入上海市治涝地方标准,对其他城市具有参考价值。     

鲁北地区"2003·10"特大暴雨分析

2003年10月9-12日,山东省北部地区发生了历史同期罕见的特大暴雨,暴雨历时长、总量大,雨后因排水不畅出现农田大面积积水,内涝严重。依据历史水文资料对暴雨特性进行了分析,以提高人们对暴雨发生规律的认识。     

西宁市短历时暴雨雨型及适用性分析

利用西宁市1954-2017年降水分钟数据建立暴雨统计样本,采用年最大值法推算暴雨强度公式并推求西宁市短历时暴雨雨型。结果表明：西宁市短历时暴雨雨型单峰特征比较明显,单峰峰值出现在前1/3。历时120 min芝加哥设计雨型综合雨峰位置系数0.27,雨峰位置在35 min左右,峰值前（后）雨强迅速增加（减小）,最大1 h降水量为13.14 mm,降水主要集中在20～80 min。各历时的瞬时雨强变化趋势以及分布型基本一致,雨强随着重现期的增大而增大。累计降雨雨峰前（后）增长斜率升（降）最大。西宁市暴雨分布呈现局地性强,空间差异明显特征,芝加哥设计雨型结果对城西和城北区代表性较好,城中和城东区可参考使用。     

南京市近25年短历时暴雨雨型特性

采用南京市7个雨量观测站近25年的逐分钟雨量资料,提取了各站30min、60min、90min、120min、150min、180min历时的暴雨样本,统计了各站暴雨年发生次数变化并比较了空间差异性,采用模糊识别法识别了各暴雨样本的雨型,分析了各历时暴雨样本雨型组成结构,从雨峰数量和雨峰系数方面探究了雨峰的分布规律,并对比了城郊暴雨雨型特征差异性。结果表明,近25年来南京市暴雨发生次数呈增加趋势,暴雨时程分配更加集中;各历时暴雨中以雨型Ⅰ(单峰且雨峰在前部)、Ⅳ(暴雨过程均匀)发生频率较大,雨型发生比例空间差异较小;各站暴雨中约有38.6%~70.2%为单峰暴雨,不同站点暴雨雨峰位置分布类似;城区暴雨发生频次更高,且未来时期持续性强降水发生几率较大,郊区暴雨雨峰出现时间比城区更早。     

基于汇水区分级划分的城市洪涝模拟

为了有效提高城市暴雨洪涝模拟的精度, 针对城区复杂下垫面和雨水井数据缺失情况, 分别提出雨水井节点数据的确定方法和基于空间信息的汇水区分级划分方法。以武汉市青山区为研究区域, 选取2场典型降水过程, 开展SWMM模型的参数率定和验证工作, 并将基于不同方法划分的汇水区模拟结果与实际渍水数据进行对比。结果表明: ①提出的雨水井节点数据确定方法, 在雨水井实测数据缺失的城市洪涝模拟中具有一定的可靠性和适用性。②基于空间信息分级划分法、水文分析结合泰森多边形法和泰森多边形法所划分的汇水区, 模拟的最大积水深度中分别有100%、63%和75%的典型验证点与实际渍水程度相符, 模拟的溢流点中分别有80.0%、76.4%和77.4%的溢流点位置与5年一遇降雨渍水风险图相符。基于空间信息分级划分法所得的汇水区比较符合真实汇水情况, 且模拟结果比其他2种方法更加准确。③ 5年一遇降雨重现期下, 3种方法划分的汇水区所模拟的积水对研究区域影响程度相对较小, 但遇到高于此重现期的暴雨会出现不同程度的内涝。本研究可为城市暴雨洪涝模拟中雨水井节点数据确定与地表空间离散化提供新方法, 模拟结果可为城市防洪减灾提供参考。     

城市暴雨过程对下凹式绿地设计参数的影响研究

为了探索城市暴雨过程对下凹式绿地设计参数的影响,使下凹式绿地的设计更为科学,根据城市暴雨产汇流过程,推导了下凹式绿地设计参数之间的关系,并以北京市大兴区一居民住宅区作为研究实例,对不同城市暴雨重现期、不同拦蓄率下的下凹式绿地设计面积、下凹深度进行了计算,结果表明,城市暴雨重现期对下凹式绿地设计面积影响最大,同时,城市暴雨重现期越长,下凹深度和拦蓄率对下凹面积的影响越大。研究结论可为城市下凹式绿地的设计应用提供参考。     

滨海城市雨潮遭遇联合分布模拟与设计

滨海城市河流常常遭受暴雨和潮汐顶托双重影响导致洪涝灾害,需要重视雨潮遭遇联合分布模拟与设计。以深圳市西乡河为例,采用年最大值法（AM）和超定量序列法（POT）两种选样方法,基于Copula方法模拟24 h暴雨遭遇日高潮位的联合分布特征,对比雨潮遭遇传统重现期和二次重现期差异,根据同频法和权函数法反推计算雨潮设计组合值。结果表明:雨潮边缘分布最优模型均为广义正态分布（GNO）,不同选样方法雨量分布模型参数差异明显。雨潮之间呈现较弱的正相依性,Archimedean Copulas均能较好地模拟雨潮遭遇联合分布特征,最优模型为Gumbel-Hougaard Copula。同频法反推雨潮设计组合值,二次重现期雨量和潮位均大于传统联合重现期,POT选样的潮位大于AM。权函数法选出的雨潮设计组合值,偏重于较高的潮位,雨量设计值较小。当明确了选样方法、联合分布模型和重现期类型,给定联合重现期的雨潮设计组合值是个此消彼长的过程,若选择较大的雨量设计值,则潮位值变小,反之亦然。从防洪潮设计安全角度考虑,POT选样方法及二次重现期设计更为安全。     

基于随机暴雨移置方法的城市设计暴雨分析

城市地区暴雨洪灾发生频繁，合理计算设计暴雨是解决城市洪涝的重要前提。采用随机暴雨移置方法（Stochastic Storm Transposition，SST），设定暴雨移置区并提取出暴雨目录，通过区域性概率重采样与暴雨空间变换相结合的方式进行降雨频率分析，估计本地化的极端暴雨频率。以上海地区为例，研究发现暴雨移置区内暴雨分布具有空间异质性，暴雨随机移置概率不均，计算得到的设计暴雨方案包含了降雨时空分布信息，在不同重现期下设计暴雨的时空结构存在变异性，说明传统方法中采用的简化雨型和均一化空间分布假设会增加设计暴雨的不确定性。     

Integration of inland and coastal storms for flood hazard assessment using a distributed hydrologic model

Due to increasing flood severities and frequencies, studies on coastal vulnerability assessment are of increasing concern. Evaluation of flood inundation depth and extent is the first issue in flood vulnerability analysis. This study has proposed a practical framework for reliable coastal floodplain delineation considering both inland and coastal flooding. New York City (NYC) has been considered as the case study because of its vulnerability to storm surge-induced hazards. For floodplain delineation, a distributed hydrologic model is used. In the proposed method, the severities of combined inland and coastal floods for different recurrence intervals are determined. Through analyzing past storms in the study region, a referenced (base) configuration of rainfall and storm surge is selected to be used for defining flood scenarios with different return periods. The inundated areas are determined under different flooding scenarios. The inundation maps of 2012 superstorm Sandy in NYC is simulated and compared with the FEMA revised maps which shows a close agreement. This methodology could be of significant value to the planners and engineers working on the preparedness of coastal urban communities against storms by providing a platform for updating inundation maps as new events are observed and new information becomes available.     

基于二次重现期的城市两级排涝标准衔接的设计暴雨

使用珠海市1984—2015年R_1h-R_6h、R_1h-R_12h、R_1h-R_24h3个历时暴雨组合推算排水排涝两级标准衔接的设计暴雨水平。应用阿基米德极值Copula与Kendall分布函数构建不同历时暴雨组合的联合概率分布模式。分析各历时暴雨组合的遭遇概率、"或"重现期、"且"重现期和二次重现期,以出现最大可能概率的方法推算各组合的设计暴雨值。结果表明:二次重现期所对应的累积频率更准确地代表了特定设计频率情况下不同历时暴雨组合的风险率;重现期分别为2年、3年、5年、10年、20年、50年、100年推算的二次重现期设计值介于"或"重现期和"且"重现期设计值之间,小于相应的边缘分布重现期设计值,R_1h-R_{6 h}组合推算的设计值相对误差为3.1%~7.1%;R_1h-R_12h组合推算的设计值相对误差为3.3%~9.3%;R_{1 h}-R_{24 h}组合推算的设计值相对误差为3.9%~12.0%。二次重现期推算的不同历时暴雨组合的设计暴雨分位值为内涝工程的风险管理和管渠尺寸提供了优选标准和设计参考。     

Rainfall thresholds for flood triggering. The case of Marathonas in Greece

Basins across Mediterranean coast are often subject to rapid inundation phenomena caused by intense rainfall events. In this flash flooding regime, common practices for risk mitigation involve hydraulic modeling, geomorphic, and hydrologic analysis. However, apart from examining the intrinsic characteristics of a basin, realistic flood hazard assessment requires good understanding of the role of climatic forcing. In this work, peak rainfall intensities, total storm accumulation, average intensity, and antecedent moisture conditions of the 52 most important storms in record, during the period from 1993 to 2008, in northeast Attica, in Greece, are examined to investigate whether there is a correlation between specific rainfall conditions and flood triggering in the area. For this purpose, precipitation data from a network of five rain gauges installed across the study area were collected and analyzed. Storms totals, average intensity, antecedent moisture conditions, and peak intensities variations were calculated and compared with local flooding history. Results showed that among these rainfall measures, only peak storm intensity presents a significant correlation with flood triggering, and a rainfall threshold above which flooding becomes highly probable can be defined.     

Sensitivity analysis of runoff hydrographs due to temporal rainfall patterns in Makkah Al-Mukkramah region,Saudi Arabia

Runoff peak and volume in flood studies are estimated relying on temporal rainfall distribution from various storm patterns. Usually, SCS distributions types (I, II, III, IA) are commonly used. Using these distributions in runoff calculations assume that the in situ temporal rainfall pattern typically behaves as the one described by the SCS-type distribution, which is due to cyclonic frontal storms and actually developed in temperate environment. To what extent such assumption is valid in the arid environment? How much the impacts of rainfall temporal patterns are reflected in runoff volumes and peaks? The aim objectives of the current study are to answer the above two questions and clarify the validity of aforementioned assumption and exemplify such effect. Real rainfall data collected from rain gauges of Makkah Al-Mukkramah region over a period of more than 20 years are utilized. Temporal rainfall patterns and their parameters are deduced. Many hydrological simulations are performed and comparisons, in terms of runoff volume and peak flows, are made to show the effects of the common rainfall storm patterns and the developed rainfall storm patterns in the region based on the current study. Results indicate that major bursts of the design rainfall storm pattern are located in the first time of the storm period in the two quartiles which is mainly due to convective rainfall type in thunderstorms unlike the commonly used by SCS types relying on frontal cyclonic storms. Makkah Al-Mukkramah temporal rainfall pattern does not behave as the “typical pattern” assumed by SCS distributions that are deduced from different environments. The impacts of the temporal pattern reflected as an overestimate in the runoff peak reached to 68 %. The developed hyetographs and tables presented in the current study are recommended to enhance economical and rational design practice in watersheds of Makkah Al-Mukkramah region.     

基于随机暴雨移置方法的城市设计暴雨分析

城市地区暴雨洪灾发生频繁，合理计算设计暴雨是解决城市洪涝的重要前提。采用随机暴雨移置方法（Stochastic Storm Transposition，SST），设定暴雨移置区并提取出暴雨目录，通过区域性概率重采样与暴雨空间变换相结合的方式进行降雨频率分析，估计本地化的极端暴雨频率。以上海地区为例，研究发现暴雨移置区内暴雨分布具有空间异质性，暴雨随机移置概率不均，计算得到的设计暴雨方案包含了降雨时空分布信息，在不同重现期下设计暴雨的时空结构存在变异性，说明传统方法中采用的简化雨型和均一化空间分布假设会增加设计暴雨的不确定性。     

基于改进填洼模型的城市洪涝灾害计算方法

城市水文模型广泛应用于城市雨洪管理研究中,但由于它无法直接给出流域的淹没情况,制约了其在城市洪涝灾害评价中的应用,因此,有必要对其进行改进。本研究开发了考虑下游影响的填洼模型,并将其与较为成熟的城市水文模型相耦合,使改进后的模型可以模拟流域的淹没状况,并在北京市天堂河流域进行了试验研究。结果表明:改进后的模型可以快速模拟流域的淹没水深及淹没范围,其淹没水深结果与相关水动力学方法模拟结果较为一致。天堂河流域河道行洪能力低于20年一遇设计标准,流域洪水风险较大的区域集中在天堂河下游区域和田营沟与永北干渠的交汇处。若在下游区域进行开发,洪水风险还可能会继续增加。     

Simulation of water levels and extent of coastal inundation due to a cyclonic storm along the east coast of India

The devastation due to storm surge flooding caused by extreme wind waves generated by the cyclones is a severe apprehension along the coastal regions of India. In order to coexist with nature’s destructive forces in any vulnerable coastal areas, numerical ocean models are considered today as an essential tool to predict the sea level rise and associated inland extent of flooding that could be generated by a cyclonic storm crossing any coastal stretch. For this purpose, the advanced 2D depth-integrated (ADCIRC-2DDI) circulation model based on finite-element formulation is configured for the simulation of surges and water levels along the east coast of India. The model is integrated using wind stress forcing, representative of 1989, 1996, and 2000 cyclones, which crossed different parts of the east coast of India. Using the long-term inventory of cyclone database, synthesized tracks are deduced for vulnerable coastal districts of Tamil Nadu. Return periods are also computed for the intensity and frequency of cyclones for each coastal district. Considering the importance of Kalpakkam region, extreme water levels are computed based on a 50-year return period data, for the generation of storm surges, induced water levels, and extent of inland inundation. Based on experimental evidence, it is advocated that this region could be inundated/affected by a storm with a threshold pressure drop of 66 hpa. Also it is noticed that the horizontal extent of inland inundation ranges between 1 and 1.5 km associated with the peak surge. Another severe cyclonic storm in Tamil Nadu (November 2000 cyclone), which made landfall approximately 20 km south of Cuddalore, has been chosen to simulate surges and water levels. Two severe cyclonic storms that hit Andhra coast during 1989 and 1996, which made landfall near Kavali and Kakinada, respectively, are also considered and computed run-up heights and associated water levels. The simulations exhibit a good agreement with available observations from the different sources on storm surges and associated inundation caused by these respective storms. It is believed that this study would help the coastal authorities to develop a short- and long-term disaster management, mitigation plan, and emergency response in the event of storm surge flooding.     

沙尘暴灾害致灾因子三维联合分布与重现期探索

探讨多致灾因子对Copula联合分布模型在三维多致灾因子综合分析中的扩展.针对沙尘暴形成的3个基本条件:大风、丰富的沙尘源和不稳定的大气层结,以内蒙古镶黄旗1990-2008年的强沙尘暴灾害事件为案例,建立了经向环流指数、地面平均最大风速和地表土壤湿度3个基本特征变量的联合分布,计算了基于联合分布的联合重现期.研究表明,镶黄旗强沙尘暴事件的三维致灾因子符合Frank Copula函数构建条件,该函数能够很好地描述强沙尘暴灾害3个基本特征变量的联合分布,具备扩展到三维的能力.相对于二维Copula函数拟合效果,三维Frank Copula在中高尾部分的拟合有很大提高.三变量联合重现期的计算结果更加贴近实际情况.