雨水径流总量控制目标确定与落地的若干问题探讨

径流污染控制和开发前自然水文状态恢复是雨水径流总量控制的出发点,径流体积控制是关键途径。总量控制包括径流体积和径流污染物总量,工程设施的工作原理不同,影响实际工程落地效果的因素包括降雨间隔时间与雨型、汇水面不透水率、设施排空时间与规模等。设施规模的确定基于降雨统计分析和模型连续计算,应根据降雨数据精度与方法各自的特点进行选择。实践中应考虑经济性、极端暴雨影响等,因地制宜地确定总量控制目标。总量控制目标的考核方式包括施工图审核与工程踏勘和模型连续计算。期望为我国雨水径流总量控制目标更科学、有效地落地提供指导。

汇水区节点选取对城市雨洪模拟结果的影响

利用Info Works ICM模型建立深圳市光明新区新城公园雨水管网模型,分别以检查井和雨水口作为模型的节点划分汇水区,分析不同的汇水区划分方式对公园出口流量模拟结果的影响。结果表明:在中小降雨条件下,汇水区节点选取对峰值流量模拟结果的影响不明显;在暴雨或特大暴雨的条件下,汇水区节点选取对峰值流量模拟结果的影响较大;与以检查井为节点的划分方式相比,以雨水口为节点的划分方式产流时间会有一定程度的推迟;在模型建立过程中应综合考虑研究目标、区域尺度和降雨特征等对汇水区进行合理划分。

Stormwater management of urban greenway in China

In order to improve the stormwater regulation functions of urban greenways on the basis of literature research and case study the relationships between urban greenway and low impact development LID and green stormwater infrastructure GSI are analyzed. Then the classification system of urban greenways is proposed based on their stormwater regulation function and the suitable technical measures for stormwater management which can be used in different kinds of greenways are selected. According to China’s urban planning system the greenway planning method combined with the urban drainage system is developed and the design methods of the greenway stormwater system and individual stormwater facilities are put forward. The relationships between the greenway stormwater system and other systems are also analyzed in terms of stormwater inlet vertical design and overflow.Finally the waterfront greenway and street greenway demonstration projects in Jiaxing City which adopts the above concept and method are introduced. The results show that the reduction rates of annual total stormwater runoff and average total runoff contaminants TSS of the stormwater system are not less than 30% and 40% respectively.

Adsorption characteristics of Pb from urban stormwater runoff by construction wastes

Construction wastes were selected as the adsorbents and static and dynamic adsorption batch experiments were carried out to investigate the adsorption of Pb to construction wastes with different particle size gradations in the simulated stormwater runoff system.The experimental results show that the pseudo-second-order kinetics model can better characterize the adsorption process of Pb than the pseudo-first-order kinetics model.The adsorption equilibrium data can be well fitted by the Freundlich isotherm model. The construction wastes with different tested size gradations can greatly remove Pb from stormwater runoff and their average removal rate can reach up to 99%.The construction wastes with narrow size distribution can better remove Pb but with worse permeability than those with wide size distribution. The particle size gradation of construction wastes greatly influences the equilibrium time rate and the capacity of Pb adsorption.The equilibrium adsorption rate and capacity are 18.1 μg/min and 5.5 μg/g respectively for the construction wastes with the size of 2.36 to 4.75 mm which are the greatest among the different size gradations.The present study provides a scientific basis for effectively controlling Pb pollution from stormwater runoff and the construction wastes resource utilization.

海绵城市建设指南解读之基本概念与综合目标

《海绵城市建设技术指南——低影响开发雨水系统构建(试行)》中涉及一系列新的基本概念、参数和方法,其控制目标也与传统排水系统有很大差异。对这些基础问题、关系与要点的透彻理解和把握,是落实海绵城市建设的重要基石。作为系列解读文章的第一篇,结合编制过程中的深入思考及长期研究和实践经验,着重阐述海绵城市的基本概念与内涵、狭义与广义低影响开发雨水系统与海绵城市的关系,以及综合目标的构建与各子目标之间的关系等基础问题,以期更清晰、科学地指导后续规划设计和建设工作的推进。

海绵城市建设指南解读之降雨径流总量控制目标区域划分

为切实贯彻《海绵城市建设技术指南——低影响开发雨水系统构建(试行)》,科学合理地确定控制目标,落实年径流总量控制,对我国大陆地区设计降雨量的地域分布特征及成因进行了分析,并结合年径流总量控制率目标确定的影响因素,论述了我国大陆地区径流总量控制目标区域划分的原则、方法及应用的注意事项,以指导相关规范标准和地方性技术导则的编制,及各地因地制宜地确定年径流总量控制率及其对应的设计降雨量目标。

海绵城市建设指南解读之城市径流总量控制指标

基于我国目前城市规划体系,提出了城市径流总量控制指标及其量化分解方法,并通过案例,利用SWMM模型对该方法进行了验证,典型年的连续模拟结果表明,利用该方法对规划区域内各地块进行控制指标分解,很好地达到了城市总体规划提出的年径流总量控制目标,可用于指导我国实施径流总量控制。

海绵城市建设指南解读之城市雨洪调蓄系统的合理构建

调蓄是城市雨洪控制利用系统和排水内涝防治规划中最重要的组成部分,通过对调蓄设施的合理设计、应用,可以很好地控制径流污染、削减径流总量和峰值、缓解洪涝灾害、利用雨水资源等。针对国内在城市雨洪调蓄的研究、规划设计和工程实施中存在的一些主要问题,首先厘清调蓄设施的不同种类及功能特点,进而提出调蓄系统的概念、构建城市雨洪调蓄系统的框架,分析调蓄系统与城市雨洪控制利用相关子系统的联系及相互衔接关系,为我国城市雨洪调蓄系统相关标准的制定、规划设计与建设提供更科学的思路和技术路线。

蓝色屋顶调节城市雨水径流的方法及可行性分析

针对我国目前一些城市所面临的开发强度大、场地受限、内涝频发、雨水径流污染严重等突出问题,介绍了利用平屋顶调节城市雨水径流的方法——蓝色屋顶。以某城市片区为例,借助SWMM模型对该片区在不同重现期下采用不同比例蓝色屋顶的雨水径流控制效果进行了模拟分析,并比较了在一定开发强度下屋顶调节与场地开发前的水文条件。结果表明:屋顶调节是削减场地开发后峰值流量的一种有效方法,尤其对一定重现期内的强降雨事件削峰效果更明显。因此,蓝色屋顶可作为城市内涝和雨水径流污染控制的有效手段之一,提高城市的"海绵"功能,尤其对于高强度开发区域,以及国内许多城市旧城改造中内涝问题的解决具有一定的借鉴意义。