变化环境对城市暴雨及排水系统影响研究进展

近年来,变化环境（气候变化和城镇化）导致城市暴雨的发生频率或强度增加,加剧了城市暴雨洪涝问题。因此,分析变化环境对城市暴雨及排水系统的影响对城市水资源规划管理、市政规划设计和城市防灾减灾有着重要意义。总结了未来高精度降雨预估技术、变化环境下排水系统设计标准等关键问题的研究进展,综述了变化环境下城市短历时暴雨演变规律及变化环境对城市排水系统影响的研究现状,探讨了变化环境对城市短历时暴雨的影响机理,并归纳了当前研究变化环境对城市暴雨及排水系统影响的主要方法。指出今后应重点加强的研究:①加强气候变化和城镇化对城市短历时暴雨影响机制的研究;②提升区域气候模式对城市区域下垫面和大气相互作用的描述能力,并加强公里尺度对流可解析模型在城市气候变化影响研究中的应用;③加强对变化环境下排水系统设计标准的研究;④综合评估气候变化和城镇化对城市排水系统超载、污染物转移和水安全等的影响。     

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。     

关于城市暴雨强度公式推求的研究

城市暴雨强度公式的准确性直接影响着城市排水管网的规划设计,老一代的暴雨强度公式已经不能正确反映当地的降雨规律,亟需重新修订。本文以郑州市降雨资料为例,采用年最大值法选样和年多个样法选样对公式进行推求,通过对比分析发现年最大值法操作简单,误差更小,该方法有利于新一轮暴雨强度公式修编的普及。     

城市设计暴雨雨型研究

采用模糊模式识别方法对我国四个雨量站的雨型进行分类和统计,获得了短历时暴雨雨型的分布特性;经过模拟分析和比较,找出了一种较好地满足城市排水设计要求的设计雨型。     

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。     

Derivation of short-duration design rainfalls using daily rainfall statistics

Design rainfall intensity–frequency–duration data are a basic input to many water-related development projects. To derive design rainfalls, one needs long period of recorded rainfall data. Although daily rainfall data are generally widely available, short-duration rainfall data are scarce. For many urban applications, design rainfalls for much shorter durations are needed, which cannot be obtained directly from daily read rainfall data. This paper presents a simple approach that can be adopted to derive design rainfalls of short durations using daily rainfall data and other physio-climatic characteristics using a novel ‘index frequency combined with parameter regression technique’. This uses L moments to reduce the impacts of sampling variability in the analysis. Furthermore, this adopts generalised least squares regression to account for the inter-station correlation of the rainfall data in the analysis. The proposed method is applied to a pilot data set consisting of 203 rainfall stations across Australia. An independent Monte Carlo cross-validation test shows that the proposed method is capable of generating consistent and accurate design rainfall estimates from 6-min to 12-h duration. The developed technique can be adapted to other countries where there is a scarcity of short-duration rainfall data, but daily rainfall data are abundant.     

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。     

城市暴雨强度公式研究进展与述评

能够客观反映城市降雨特征与规律的暴雨强度公式是城市排水防涝基础设施建设、海绵城市建设过程中相关工程规划、设计的重要前提。简述了暴雨强度公式推求的过程,从暴雨强度公式型式、暴雨资料选样方法、频率曲线选择、频率曲线参数估计以及暴雨强度公式的参数求解等方面,系统梳理了国内外发展现状,深入分析、归纳了各种方法的优缺点,对暴雨强度公式编制过程中存在的两步最优与直接拟合、公式拟合的"异参同效"、公式及参数合理性分析以及编制长历时暴雨强度公式等问题进行深入剖析,认为暴雨强度公式还需在全要素误差分析、成果合理性检验、降雨空间分布、气候变化对城市未来降雨的影响等方面进行深入研究。     

Multiple rainfall event pollution transport by sustainable drainage systems: the fate of fine sediment pollution

A key design criterion of sustainable urban drainage systems is to mitigate urban stormwater pollution. Current research defines sustainable urban drainage systems (SuDS) pollutant treatment efficiency through the detention of total suspended solids, urban nutrients and heavy metal pollutants within the system during a design flow event, with research focusing on sand (>2 mm) sediment movement. The impact of multiple rainfall–runoff events on the fine sediment (<2 mm) treatment efficiency of SuDS is not yet well defined, and the temporal movement of detained sediment has not been investigated in detail. The field research presented in this paper addresses this research gap, monitoring ongoing fine sediment transport through a best-practice-designed SuDS network over 12 months through the use of a novel rare earth oxide trace methodology. Through time-stepped monitoring of the fine sediment pollution across three SuDS treatment trains (networks), the following key conclusions have been drawn. (1) That fine sediment becomes re-suspended and re-deposited within SuDS assets and the network as a result of ongoing multiple rainfall–runoff events. (2) That this re-suspension continues for over 52 weeks. (3) That by area, linear wetlands (within the monitored networks) outperform wetland and swale assets in multiple event fine sediment detention. And (4) that multiple event monitoring and analysis of fine sediment within a SuDS network highlights the under-performance of SuDS assets against current design event expectations.     

基于MIKE 11的北京市典型区域降雨径流特征研究

以北京城市化发展区凉水河大红门闸控制流域为典型区域,在分析区域20世纪80年代到2000年后下垫面变化特征的基础上,结合区域同时期的降水和径流资料,采用MIKE11软件中的UR-BAN模块构建流域降雨径流模型,以流域模拟流量和实测流量拟合效果最佳为原则,利于多场次的实测降水进行降雨径流的模拟分析,研究区域城市化发展对水文特性变化的影响。     

植草沟滞蓄城市道路雨水的试验及模拟

为定量分析植草沟的水文性能,优化其设计参数取值,通过植草沟滞蓄城市道路雨水的试验设施开展模拟径流试验,验证了SWMM （storm water management model）模型模拟植草沟滞蓄效果的可行性,通过模型情景分析提出了设施的优化设计参数,评估了设施对提高道路排水标准和长期径流削减的影响。研究结果表明:SWMM模型对模拟植草沟水文性能具有较好的精度,对较小的降雨重现期和边坡比,较大的滞蓄深度、植被覆盖率和面积负荷比,植草沟的滞蓄能力更强,建议其设计降雨重现期不超过10年,滞蓄深度为10 cm以上,边坡比至少为3,植被覆盖率为0.5以上,面积负荷比为5%以上。模拟北京某城市道路采用植草沟设施后,可将3年、5年、10年的排水标准分别提高到15年、20年、30年,在长达64年的运行中,植草沟几乎可消纳自身及汇水区域内所有径流,可为道路植草沟的设计和应用提供参考。     

基于GLUE方法的城市雨洪模型参数不确定性分析

以北京市大红门排水片为例,构建基于SWMM(Storm Water Management Model)的城市雨洪模型,并基于GLUE方法(Generalized Likelihood Uncertainty Estimation)对模型参数的不确定性进行了分析。结果表明,所建城市雨洪模型能够较好的模拟区域的雨洪过程。在模型参数中,管道曼宁系数、不透水区洼蓄量以及河道曼宁系数的不确定性对模型结果的影响较为显著。GLUE方法能够在分析模型结果不确定性的同时给出敏感性参数,为城市雨洪模型的参数率定和进一步研制提供了有效工具。     

SCS模型中城市地区土壤AMC确定方法的改进及应用研究

估算径流曲线值(CN)是采用SCS模型模拟径流的重要过程,而土壤前期湿润程度(AMC)是估算径流曲线值的主要影响因素,一般采用某次降雨前5d的降雨量来确定土壤AMC。以松花江流域大中小三种规模城市——哈尔滨市、长春市、佳木斯市、吉林市、梅河口市和勃利县城区为例,分析了土壤AMC计算方法的适用范围及存在的问题,并提出了改进方法。研究表明,原方法适合于城区绿地,但不适合于城区其他土地利用类型。对土壤AMC的计算方法进行改进,以某次降雨前5d降雨量与气象蒸发量差值确定其他土地利用类型的土壤AMC,经过对比分析发现,在除绿地外的其他土地利用类型中,改进方法优于原有方法。     

基于数值模拟的城镇地质灾害危险性评价方法

定量计算城镇尺度地质灾害不同降雨强度下的危险性是地质灾害风险评价中的难点。以红层地区群发性浅层滑坡链式灾害为研究对象,探索一种新的城镇尺度下的地质灾害危险性量化评价方法,为城镇地质灾害风险评价奠定基础。通过查询喜德县米市河区域不同降雨频率下降雨参数,统计分析国家雨量站数据及近50 a的18场群发性地质灾害降雨历时、雨型分布特征。以土层厚度、植被覆盖度及地形数据处理为基础,基于STEM TRAMM数值计算方法及降雨分布曲线计算城镇地质灾害危险性,绘制研究区地质灾害危险性评价图。通过遥感解译数据、地面调查数据及灾害数据库数据与数值计算结果对比,表明应用降雨特征统计及STEM TRAMM数值计算方法精细化评价红层地区城镇地质灾害危险性具有良好的适应性、便捷性及科学性,可为其他不同孕灾背景下的城镇地质灾害危险性评价提供思路。     

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。     

The definition of urban stormwater tolerance threshold and its conceptual estimation: an example from Taiwan

The combination of climate change and urbanization is worsening urban flooding problems. Estimating the amount of rainfall that a city can tolerate without flooding is a fundamental task that is difficult to perform, although large amounts of resources are invested in urban flood control. The purpose of this study is to determine the tolerance threshold for stormwater in a city. Based on hydrometeorological characteristics and existing flood control facilities, the urban adaptive water capacity is analyzed to determine the critical rainfall loading. Different critical levels are defined. The low critical point represents the beginning of the water accumulation, while the intermediate and high critical points are defined as flooding with heights of 300 and 600 cm, respectively, in low-lying areas. This study adopts a simple conceptual method to illustrate the critical levels instead of applying complex hydrologic and hydraulic modeling, which require high-resolution spatial data. Three cities and one township in Taiwan are used as urban case studies and to verify the conceptual method. As the capital, Taipei City utilizes the highest flood control engineering technology of our case studies; it is also the site in which the lowest rainfall thresholds cause the accumulation of water to reach the intermediate and high critical points because its small ‘internal water areas’ increase the height of floods rapidly. Conversely, Taichung City has a large internal water area that can disperse accumulating waters without increasing flood height. The estimations of urban storm tolerance thresholds increase the understanding of the limitations of water protection facilities. These estimations may be combined with rainfall forecasts to increase early warning functions and provide a reference point for subsequent planning related to urban flood adaptation strategies.     

A probabilistic approach for estimating return period of extreme annual rainfall in different cities of Punjab

Multi-day rainfall events are an important cause of recent severe flooding in Pakistan, and any change in the magnitude of such events may have severe impact upon urban structures such as dams, urban drainage systems, and flood. This article uses statistical distributions to define extremes of annual rainfall of different cities of Punjab (Lahore, Murree, Sialkot, and Jhelum) with given return periods. Our calculations suggest that general extreme value is the best-fitted distribution for the extreme annual rainfall of different cities of Punjab. Our calculations show that different cities of Punjab have 5 years return period for receiving more than 100 mm daily rainfall. While they have 30 years return period for receiving more than 200 mm daily rainfall. This asks for construction of new dams in Pakistan.     

Severe wet spells and vulnerability of urban slopes: case of Singapore

Tropical areas like Singapore characteristically receive heavy and prolonged periods of rainfall. During these wet spells, many of the urban engineered slopes become susceptible to landslides, causing much damage to property and causing disruption to urban life. Studies on relationships of wet periods and landslides events reveal that while the weathered materials on urban engineered slopes tend to fail regularly in response to discrete, heavy rainstorm events, they are also closely associated with long periods of antecedent rainfall conditions which often help to reduce the threshold value of discrete rainfall events. Past records of slope failures and recent episodes of failures in Singapore are examined to re-assess this relationship. Study found that there is indeed a close association between the two aspects of any rain event and co-occurrence of the two lead to widespread slope failures.     

城市降水径流的污染来源与排放特征研究进展

综述了城市地表径流污染的成因、来源和排放特征的研究.城市降水径流污染来自3个方面:降水、城市地表和排水系统.其中,城市地表和排水系统是城市降水径流污染的主要来源.在具合流制排水系统的城市,20%~60%的径流污染(SS、COD和BOD₅)来自排水系统.在一次降雨过程中,城市降雨径流污染的排放一般存在初期冲刷效应,径流中污染物浓度的峰值一般提前于径流的峰值.但是由于影响初期冲刷效应的因素多而随机,使得初期冲刷出现的频率和程度存在明显的差异,而且很难建立初期冲刷与降雨特征和流域特征的通用关系.     

浅谈水文地质勘查工作在海绵城市建设中的重要作用

海绵城市是指通过加强城市规划建设管理,充分发挥建筑、道路和绿地、水系等生态系统对雨水的吸纳、蓄渗和缓解作用,有效控制雨水径流,实现自然积存、自然渗透、自然净化的城市发展方式。其本质是要实现有效的径流控制,不仅要从形成雨水径流的源头着手,而且要考虑城市“海绵体”的岩土性质,其渗透能力(降雨渗透系数)、储存雨水能力(地下含水层储存空间大小)及储存雨洪的危险性(诱发环境地质问题)等。这些问题与水文地质勘查工作密切相关,不可或缺,是海绵城市建设规划、设计前的最基础性工作。