Semi-probabilistic design of rainwater tanks: a case study in Northern Italy

The paper proposes a semi-probabilistic approach for the design of rainwater tanks. In particular, the cumulative distribution function of the active storage is derived as a function of rainfall moments. The model is validated through continuous simulation of the hydraulic behaviour of a hypothetical rainwater tank located in Milan (North Italy) using as input a series of rainfall records.     

初期雨水调蓄池运行效率的计算机模型评估

利用排水系统水力模型对上海世博园区的规划雨水系统进行了水力模拟,评价了初期雨水调蓄池控制城市面源污染的长期效果.结果表明：按照调蓄容量为30 m3/hm2的设计标准,在上海市平水年降雨条件下,调蓄池每年能够拦蓄约50%的雨水径流量;在分流制雨水系统具有一定初期效应的情况下,上述初期雨水调蓄池污染物的去除率为42.9%～67.4%;对于半分流制系统,在降雨期间允许向污水总管截流初期雨水的条件下,调蓄池具有更高的截流比例.     

Modelling the performance of rainwater collection systems: towards a generalised approach

The collection of rainwater from roofs, its storage and subsequent use make a significant saving in the use of potable water. This paper investigates how spatial and temporal fluctuations in rainfall can be incorporated into behavioural models, which simulate the performance of rainwater collectors. Temporal variations are considered at two different time scales, that is daily and monthly intervals. The first model uses a daily time interval to model system performance. A set of rainwater collector performance curves for five geographic locations is developed. From the location-specific curves, a set of average curves is determined which is shown to be sufficiently accurate for estimating rainwater collector performance. The second model uses a larger time interval of one month. The effect of daily fluctuations in rainfall is incorporated into this model using a storage operating parameter. Values of the parameter were determined by matching the output from the daily model with that of the monthly model. Generally the rainwater collector performance predicted by the monthly model using average values of the storage operating parameter is shown to correlate well with the corresponding values determined using a daily time interval model. The monthly model provides a simple and versatile method of modelling the performance of rainwater collectors.     

基于北方平原城市特点的雨水系统优化设计

针对北方平原城市地势平坦、河道水位顶托、夏季降雨集中的特点,对集流时间、汇水面积、径流系数、暴雨重现期、淹没流速、雨水口等几个市政雨水管网设计中的要素进行分析,提出了最佳取值的选取方法,以达到优化设计的目的。     

Rainfall input requirements for hydrological calculations

Rainfall is the most important input for many hydrological and hydraulic design calculations. Ideally, long historical rainfall series should be used and a statistical analysis should be performed on the hydraulic results afterwards. In combination with the detailed models that are commonly used nowadays, this leads to huge calculation times. This research was set up in order to verify which kind of simplifications can be made with respect to the rainfall input. One must find an optimum between accuracy of the modelling results and calculation effort. This optimum can be different for different applications. The different types of rainfall simplifications which are considered here are composite design storms, short selected rainfall series and modified single storm events. In many cases the optimum is more likely a simplified model in combination with continuous long term simulations. Well-calibrated (physically based) simplified models can reach almost the same accuracy as the corresponding detailed models within a fraction of the calculation time. Furthermore, these simplified models are very useful in order to select or compose the proper rainfall input for detailed modelling.     

如何优化城市住区绿地布局形态管理场地雨洪？ ——基于重庆某住区的模拟实证研究

国内外学者针对雨水管理目标下的 城市住区场地设计展开了较多研究,但对住 区绿地系统的形态特征和径流控制的定量关 系还缺乏相关探讨。研究对住区绿地形态特 征与径流水系特征进行归纳分类,然后选择 Uwater Drainage作为场地场次降雨径流的 模拟软件,基于重庆某住区设计方案展开降 雨径流的实证模拟研究。研究了住区建筑布 局与绿地形态对降雨径流的影响特征,探索 了整合雨水管理功能的住区绿地系统复合结 构。通过将雨水管理目标融入住区规划设计 阶段,有利于住区更加有效地实现雨水管理 目标。     

干旱区雨水蓄水池容积的设计计算

通过分析雨水蓄水池有效容积与其工程投资、节水效益之间的关系,以降雨资料为基础,建立了根据小区面积推求该小区雨水蓄水池的经济容积的计算方法。以西安市某建筑小区为例,结合西安市的降雨资料,计算得出该小区的雨水蓄水池最佳设计容积。同时,通过折算不同规模和组成的小区的占地面积,确定了不同产流面积下的雨水蓄水池经济容积。     

上海市降雨特性统计与雨水存储池容积计算

介绍了雨水利用系统存储池容积的设计方法.通过统计分析上海市近20年的降雨资料,获得了独立降雨事件的降雨量、降雨历时和降雨间隔的平均值以及各降雨特性参数的概率密度函数,在此基础上运用概率统计方法进行了雨水存储池集蓄效率的分析计算.通过对概率密度函数的积分,获得了不同容积下存储池的集蓄效率及相应的年均集蓄水量.结合雨水利用系统的投资、运行费用与预期水价,可确定相关存储池的合理容积.应用该方法评价了上海世博园区屋面雨水集蓄工程存储池的合理容积.该方法对雨水集蓄利用工程的设计具有普遍意义.     

计算机模拟技术在镇江市城区排水管理中的应用

根据镇江市的地面积水点、排水管道水位、雨量自动监测和天气预报数据,应用SWMM5.0软件建立了城区排水管网的计算机模拟模型,它可对不同强度的降雨是否产生城市内涝灾害进行模拟,预测特定地点在降雨之后的积水状况,预警暴雨灾害,发布沥涝预警信息,及时为城市暴雨事故抢险和雨季交通管理等提供科学决策依据.     

西北半干旱地区老旧小区海绵化改造研究——以西宁试点区湟水花园为例

老旧小区海绵化改造是在国家海绵城市试点建设过程中源头治理的重点和难点。以西宁市试点区湟水花园为例,探讨在西北地区半干旱气候条件下老旧小区海绵化改造的方法和技术,实现径流控制、削峰延时、环境提升等综合目标。利用地表组织径流雨水,采用低影响开发设施调蓄雨水,并局部结合管渠排水的方式,增加了小区雨水调蓄、传输、排水能力。在3年一遇2 h降雨条件下,小区2处雨水管网排出口流量值分别降低了44.07%、50.38%,峰值时间分别延迟了5、3 min,起到了一定的削峰延迟效果;在50年一遇的降雨条件下,小区无内涝积水现象。同时,通过构建SWMM模型,以2018年全年连续降雨进行模拟,得出小区年径流总量控制率达82.5%,实现了设计目标要求;充分说明了湟水花园采用的改造方法成功有效,能够为今后西北半干旱地区老旧小区的海绵化改造提供借鉴和经验。     

侨香村雨水收集与利用系统的设计

介绍了侨香村小区工程概况、设计原则，进行了雨量计算，并做了雨水收集与利用系统设计的介绍，最后提到了雨水收集与利用系统对建筑设计的影响。     

A Pb isotope and trace element study of rainwater from the Massif Central (France)

Lead isotope ratios and Zn, Pb, Cu, Cd, Sb and Rb contents were measured in samples of rainwater collected over a period of 15 months from the Massif Central (France). Each sample, collected automatically at monthly intervals, represents a series of rainfall events. Rainwater chemistry was interpreted in terms of the chemical contributions from wet deposition and from different source regions for dust in the centre of France. Trace element concentrations in rainwater samples showed a wide range, particularly for Pb (1.30-465 microg/l), with variations decreasing for Cd (0.07-1.70 microg/l), Zn (1.00-54.00 microg/l), Cu (0.20-25.00 microg/l), Sb (approximately 0-0.33 microg/l) and Ni (approximately 0-15.00 microg/l). Trace element contents do not correlate with rainfall amount and no inter-element correlations are evident in the data. Lead is the most common trace metal found in the rainwater (mean value = 996 microg/m2/y) while Sb is the least common element measured (mean value = 1.12 microg/m2/y). The composition of rainwater collected from the Massif Central shows a range in Pb isotope ratios from 17.935 to 19.22 (206Pb/204Pb), 15.578 to 15.73 (207Pb/204Pb) and 37.559 to 38.606 (208Pb/204Pb). A five-component mixing model involving contributions from the natural background, gasoline inputs from industrial and agricultural activity and a source resulting from mining waste may be used to explain both the Pb isotope signature and the fluctuations in trace metal contents of Massif Central rainwater.     

厦门雨水利用设计

介绍厦门降雨概况和淡水资源严重缺乏的现状,结合厦门某小区雨水收集回用方案及主要设计参数的取值,提出了对厦门雨水利用设计的几点建议。     

雨水利用在公园景观设计方面的应用

雨水利用具有重要的经济与生态效益,将雨水利用纳入城市景观设计,不仅有助于缓解水资源的短缺,改善生态环境,同时还能创造出多功能的水域空间和景观.文中探讨了城市公园雨水利用的设计方法,并以深圳某公园为例进行具体设计和分析.     

Effectiveness of filter gabions against slope failure due to heavy rainfall

Slope failures due to heavy rainfall events are phenomena that can cause serious damage to social infrastructures and the loss of lives. Based on previous studies, natural slope failures are generally shallow and originate at the slope toe where infiltrated rainwater has accumulated and saturated it. Hence, it is extremely important to prevent these initial failures from inducing entire slope failures. In the present study, firstly, 1 g model tests, called G series tests, were conducted. In the tests, a gabion filled with filter materials was placed at the slope toe of each model for reinforcement and to drain the accumulated rainwater from the slope toe. Filter gabions have been found to shrink the failure regions and to significantly extend the time until slope failures occur. The failure mechanism in the G series tests was almost similar to that in cases without filter gabions if focus was placed on the slope above the filter gabions. However, the drainage effect was small. Secondly, P series tests, in which a filter gabion with a pipe was introduced for each model, were conducted. The results of these tests indicated that the displacements significantly decreased as the diameter of the pipe and the depth of the pipe’s insertion to the surface layer increased. Water did not discharge through the pipe until the pore water pressure around the pipe reached positive values. The failures always started when a phreatic surface appeared on the slope surface. Thus, it is very important to prevent a phreatic surface from forming on the slope surface. The adequate arrangement of a filter gabion with a drainage pipe may increase the potential for slope stability.     

设置调蓄池的雨水管道设计计算

设置雨水调蓄池是城市雨水利用的有效措施,但目前国内还未有设置调蓄池的雨水管道设计计算方法.为此,结合雨水管道设计的推理法和管道空隙容积理论,提出了通过设置雨水调蓄池,使上游雨水全部持续进入调蓄池而延长下游管道的汇流时间t,的合理假设,计算下游雨水管道的降雨历时应包括地面集水时间t1、折减条件下管道流行时间mt2和上游管道的设计流量充满调蓄池的时间t3,从而得到了适用于设置调蓄池的雨水管道设计公式,并将其应用于西北某规划科技园的雨水利用系统的管道设计中,与传统的设计方法相比,提高了系统的雨水调蓄功能,并降低了管道造价.     

城市雨水集蓄利用工程规模的优化

通过分析雨水贮存池容积、多年平均日降雨量、满蓄次数等关系，依据贮存池的工作过程和费用效益分析原理提出了雨水贮存池经济规模优化求解方法，进而对优化设计中常见的关键问题进行了讨论，如贮存池满蓄次数、可收集水量、投资与成本、综合效益、资金时间价值等。该方法具有一定的通用性和实用性，可以作为城市雨水利用工程优化设计的理论依据和实用技术。最后对北京地区某工程实例进行了应用分析。     

水质调蓄池在分流、合流制排水系统中的应用

在水质型缺水的城市,设置水质调蓄池,可以减少雨水或合流污水排放至河道的量;在降雨历时较短、降雨总量较小时,还可以做到雨水或合流污水对河道的零排放,从而减小排入水体的污染物总量。结合上海市大定海排水系统工程设计实例,介绍了水质调蓄池在分流、合流制排水系统中的作用、有效容积计算、定性和定量地分析截污效果。最后介绍了水质调蓄池运行模式。     

昆明市城市雨水工程设计降雨量的选取及案例分析

根据昆明市截污、节水的实际情况及要求,以低影响开发理念为依托,确定了近期昆明市城市雨水利用工程的设计降雨量,并通过实际工程案例的分析,证实从控制雨水外排径流量、削减径流污染的角度选取25.5 mm/d的设计降雨量是可行的,同时对工程案例中存在的问题提出了针对性的措施和建议。     

《建筑与小区雨水利用工程技术规范》编制探讨

雨水利用工程的适用条件、水量平衡计算、下垫面径流系数的确定等是《建筑与小区雨水利用工程技术规范》编制中需要解决的关键技术。从工程总体、雨水入渗系统、收集回用系譬，方面进行了详细的技术探讨。另外分析了流量径流系数和雨量径流系数，并提出利用径流系数实现对雨水利用工程效果的评估。