Performance of lot-level low impact development technologies under historical and climate change scenarios

Low impact development (LID) systems have potential to make urban cities more sustainable and resilient, particularly under challenging climate conditions. To quantify performance capabilities, modeling results for an array of combinations of LIDs are described using PCSWMM at lot-level to examine performance of individual LIDs on volume and peak flow reductions. Among the four LIDs studied: rain barrel (RB), vegetative swale (VS), bioretention cell (BC), and permeable pavement (PP), PP at lot-level demonstrated the best capability for reducing surface runoff volumes and peak runoff rates under historical weather conditions, while BC showed similar capability for reduction of runoff volumes but minimal peak flow reduction. With PP as the controlling method at lot-level, the maximum percentage reduction of runoff volume for a 2-year storm is 58% whereas for a 100-year storm, the runoff volume reduction is 20%. These results mean the extent of flooding that may arise from the 100-year storm is reduced, but not eliminated. Effectively, the 100-year storm volumes with LID are devolved to have flooding equivalent to a 25-year storm. Under climate change scenarios, performance for all LIDs declined at various levels, where BC was the most resilient LID for a climate change scenario, such that projected 2-year or 5-year storms with climate change will have its impact devolved with LID in place, to result in similar volumes and peaks without LID under historical conditions. Furthermore, even with an assembly of lot-level LIDs distributed throughout the community, there is not attenuation to substantial degrees of flooding for major events, but there can be effective control for water quantity for small (2- to 5-years in particular) storm events.     

基于SWMM的铁心桥实验基地内涝防治效果模拟

基于南京水科院铁心桥实验基地的地形、下垫面条件等数据构建了SWMM,模拟了实验基地象目湖观景平台和水上餐厅两个监测点在不同降雨重现期、低影响开发措施、溢流孔设置和水泵强排条件下受淹情况。结果表明,初始水位较低(25.1 m)时,象目湖遭遇500年一遇的降雨事件时水位并未抬升至水上餐厅。初始水位较高(25.6 m)时,200年一遇和500年一遇的降雨事件中水上餐厅受淹持续时间分别为7 h和11 h。采用集水池、雨水花园和生物滞留池3种LID措施对象目湖水位峰值影响模拟结果显示,在5年或10年一遇的降雨事件中雨水花园和集水池可以分别降低象目湖峰值水位0.06 m和0.02 m,生物滞留池没有削减峰值水位。在降雨量为218.5 mm的20160707次降雨事件中LID措施削减象目湖水位效果不明显。水泵抽排流量越大,象目湖水位越早回落到观景平台以下。LID在应对造成城市内涝的低频次、短历时强降雨方面作用有限,铁心桥实验基地象目湖内涝防治应以加强水文气象预测和水位管理、加大溢流孔尺寸和采用水泵强排等措施为主。     

Community Discovery with Location-Interaction Disparity in Mobile Social Networks

With the fast?growth of mobile social network, people ’s inter?actions are frequently marked with location information, such as longitude and latitude of visited base station. This boom of data has led...     

Evaluation of performance of Active,Beautiful and Clean (ABC) on stormwater runoff management using MIKE URBAN: a case study in a residential estate in Singapore

ABSTRACT

Singapore has adopted a low impact development equivalent of stormwater management philosophy under a national program called ‘Active, Beautiful and Clean’ (ABC) employing soft-engineering techniques to manage rainfall runoff in the face of climate change and rapid urbanisation. This study makes use of the MIKE URBAN modelling tool to evaluate the performance of ABC units in a new residential precinct based on flow data collected. Calibration results show an overall good fit between the measured data and simulated results based on three goodness-of-fit stats. The runoff factors computed for scenarios with and without the presence of ABC units show an improvement in the range of 21–72%. This study demonstrates the usefulness of using a calibrated model to evaluate the performance of constructed units using measurements. It is recommended that this modelling tool be also used for evaluating water quality performance of the units as well as applying it for use in the planning and implementation process.     

基于低影响开发理念的雨水控制设计计算

文中介绍了某电影文化综合体项目采用的集中雨水控制利用技术:透水性地面铺装、屋顶绿化、下凹式绿地、微生态雨水处理回用一体机。通过合理划分汇水面积,结合项目实际情况,计算给出了在限定年径流总量控制率的条件下,合理采用多种手段联合,使项目符合《绿色建筑评价标准》(GB/T 50378—2014)中的场地生态设计要求,实现了海绵城市的控制目标,也为类似工程提供了参考思路。     

海绵城市低影响开发措施综合效益评价体系及应用

为对低影响开发(LID)措施综合效益进行量化评价,综合考虑生态、经济及社会等因素,选取径流量削减率、污染物削减率、成本投资、运行效益、雨水利用、生态价值等16项LID措施评价指标,采用层次分析法和熵权法确定指标权重,基于云模型构建了 LID措施综合效益评价体系.将评价体系应用于南京一住宅小区的4个LID措施初步设计方案...     

LID组合措施在杭州低影响开发区项目中的应用研究——基于SWMM模型

结合杭州市低影响开发区对雨水控制的要求,运用SWMM模型模拟常规开发模式、组合LID设施、组合LID+蓄水池对雨洪控制的效果.研究结果表明,组合LID设施可以有效降低场地内洪峰流量、径流系数,并使场地在50 a重现期以下的降雨情况无溢流节点;组合LID+蓄水池可以控制杭州市100 a重现期2 h短历时降雨量的94.3％...     

国外雨水管理理念与实践

近年来,城市暴雨内涝问题得到各界广泛关注,城市雨水管理的重要性日益凸显。本文研究了国外雨水管理的发展历程,概述了"最佳管理实践"、"低冲击开发"、"水敏城市设计"和"可持续性城市排水系统"等国际主流城市雨洪管理策略,同时对近年来世界先进城市防治内涝方面的管理措施进行了归纳总结;最后,在思想意识、排放体制、措施等方面与中国目前排水体制进行了对比,并归纳了三种理念的适用范围,希望根据国内实际条件的不同,因地制宜地制定适合中国特色的雨水管理理念。     

中国海绵城市——一座巨型绿色屋顶实验室

绿色屋顶是雨洪管理中一项重要的低影响开发（LID）措施。由于气候变化和城市快速发展,LID雨洪管理策略对于当下全球的城市设计都至关重要,尤其是在经济蓬勃发展历来又饱受洪水灾害的中国。气候变化导致降水事件及雨水径流峰值流速难以准确预测。面对建筑布局日益稠密、不透水下垫面日益增多的中国城市,设计师们需要随时做好应对城市雨洪问题的准备。2015年提出的“海绵城市”战略为在城市尺度下应用和监测绿色屋顶效益提供了机会。目前业内大多数国际性绿色屋顶的研究应用都局限于小型控制实验区,借海绵城市建设之东风有机会将应用实验扩展到城市规模。中国雨洪管理智慧的历史可以追溯至5 000年前,现今中国正处于成为大尺度绿色屋顶实践世界领先者的机遇期。因此,LID应是城市设计的驱动力量而非事后补救措施。景观设计师不仅能够从场地、城市和区域3个层面上对场地及其周围环境进行全面解读,而且对需要实施LID的其他因素也有全面认知。为探究中国雨洪管理结构提供了新的视角,对景观设计师如何参与LID实践提出了建议。     

基于SWMM模型的LID措施年SS总量去除率计算

由于SWMM(storm water management model)模型在进行污染物模拟时并未考虑LID(low impact development)措施的净化作用,致使计算年SS总量去除率时存在较大误差,为弥补该误差,本研究提出了一种基于SWMM模型并考虑LID措施净化作用的年SS总量去除率值计算方法。以深圳市玉田河流域为例,构建SWMM模型,结果表明,年SS总量去除率值不考虑LID措施净化作用时为23. 2%,考虑LID措施净化作用时为30. 1%,后者为前者的1. 3倍。同时论述了年径流总量控制率和年SS总量去除率的概念差异,指出两者之间并无确定比例关系。因为LID主要截留初期中小降雨,在考虑初期雨水冲刷效应的情况下,典型地块年SS总量去除率值可能大于年径流总量控制率值。