Plant Selection and Application of Rain Garden in Southern China

Based on the basic principles of rain garden infrastructure, optimal species for rain facilities such as vegetated buffer strip, vegetated shallow groove, artificial wetland were selected, characteristics, configuration principles and methods were summarized.

On Waterscapes in Urban Residential Area from the Perspective of Rain Garden and Eco-pool Designs

Due to the high cost for operating and maintaining waterscapes, waterscapes in many residential areas have been laid aside and even become pollution sources. Taking MCC Beiluyuan (Residential Area) in Chongqing Municipality for example, concrete strategies of using natural terrains to design rain garden and eco-pool, collect rainwater, construct bottom of the bath, and combine plants were introduced, so as to explore a new approach of creating green and ecological modern residential landscapes.

Modeling 3D Ex-Filtration Process of a Soak-Away Rain Garden

This paper presents a three-dimensional (3D) model developed using COMSOL Multiphysics to understand the 3D ex-filtration process of a soak-away rain garden. With a design hyetograph of 3-month average rainfall intensities of Singapore, it is found that the average vertical ex-filtration rate that is obtained by dividing the average vertical ex-filtration (drained through bottom of the soak-away rain garden, averaged over the simulation period = 720 min, and expressed in m3) by the surface area of the soak-away rain garden and the simulation time step is almost constant regardless of increase in saturated hydraulic conductivity (K) of the in-situ soil and the surface area of the soak-away rain garden as a percentage of catchment area. However, as depth to groundwater table which is measured from bottom of the filter media increases, in between 0.5 m and 1 m of depth to groundwater table, the average vertical ex-filtration rate decreases significantly (by around 15 - 20 mm/hr) and the decrease is almost twice, compared with that between 1 m and 1.5 m of depth to groundwater table. Furthermore, this study shows that for a given K of in-situ, K of filter media, and depth to groundwater table, as the surface area of the soak-away rain garden increases, the horizontal flow coefficient which is defined as the ratio between total horizontal ex-filtration (drained through sides of the soak-away rain garden, summed over the simulation period, and expressed in m3) and total vertical ex-filtration (drained through bottom of the soak-away rain garden, summed over the simulation period, and expressed in m3) decreases. Moreover, for a given surface area of the soak-away rain garden, K of in-situ, and depth to groundwater table, the horizontal flow coefficient decreases as K of the filter media increases. However, it is found that for a given surface area of the soak-away rain garden, K of in-situ, and K of filter media, the horizontal flow coefficient increases as depth to groundwater table increases.

Easy-to-Use Look-Up Hydrologic Design Charts of a Soak-Away Rain Garden in Singapore

As catchments become urbanized due to population growth the impervious surfaces created by buildings and pavements in the expense of permeable soil, depressions, and vegetation cause rainwater to flow rapidly over the landscape. To mitigate the adverse impact of urbanization such as increased flooding and depleted groundwater recharge, around the world, several best management practices, in other words, green infrastructures have been practised, and soak-away rain garden is one of them. However, to have a rapid assessment of soak-away rain gardens on a range of potential hydrologic conditions (e.g., size of the soak-away rain garden, saturated hydraulic conductivity of the in-situ soil, and saturated hydraulic conductivity of the filter media), hydrologic design guidelines or design charts of soak-away rain gardens that are specific for local conditions are not currently available for many regions including Singapore. Thus, in this paper, with a design hyetograph of 3-month average rainfall intensities of Singapore, hydrologic design charts, especially, design charts on overflow volume (as a % of total runoff volume) of soak-away rain gardens are established for a range of potential hydrologic conditions by developing a mathematical model based on Richard’s equation using COMSOL Multiphysics, a finite element analysis and solver software package for various physics and engineering applications. These easy-to-use look-up hydrologic design charts will be of great utility for local managers in the design of soak-away rain gardens.

Multiple Regression Model of a Soak-Away Rain Garden in Singapore

Under the possible hydrological conditions, with a design hyetograph of 3-month average rainfall intensities of Singapore, multiple regression equations on hydrological processes, specifically on overflow volume, average vertical ex-filtration rate and horizontal flow coefficient, of a soak-away rain garden are established based on simulated results of a mathematical model. The model that is based on Richard’s equation is developed using COMSOL Multiphysics. The regression equation on overflow volume and the regression equation on log of horizontal flow coefficient show a very strong relationship with the independent variables (saturated hydraulic conductivity of the filter media, saturated hydraulic conductivity of the in-situ soil, depth to groundwater table, and surface area of the soak-away rain garden). The coefficients of determination of the fitted equations on overflow volume and log of horizontal flow coefficient were 0.992 and 0.986, respectively. However, the regression equation on average vertical ex-filtration rate has high p-values (p-values > significance level, α = 0.01) for saturated hydraulic conductivity of the in-situ soil and surface area of the soak-away rain garden. Thus, forward stepwise regression was used to develop the best regression equation on average vertical ex-filtration rate with saturated hydraulic conductivity of the filter media and depth to groundwater table. The coefficient of determination of the fitted equation was found to be 0.911. These easy to use regression equations will be of great utility for local mangers in the design of soak-away rain gardens.

An Interface to Model 3D Hydrological Process of a Soak-Away Rain Garden

To mitigate the adverse impact of urbanization around the world, several best management practices, in other words green infrastructures, have been used in a way that protect the natural hydrology of the catchment and are more beneficial to the environment. Soak-away rain garden, shallow, landscaped depressions commonly located in parking lots or within small pockets in residential areas, is one of those best management practices or green infrastructures. However, though in the past few decades the mathematical modeling work and the science of computer simulation have enhanced the understanding of hydrological processes, there is still a lack of modeling studies that focus on understanding the three-dimensional (3D) hydrological processes, such as the 3D ex-filtration process of a soak-away rain garden in a sufficient level of details. Thus, this paper develops a 3D mathematical model to represent the hydrological processes of a soak-away rain garden using COMSOL Multiphysics Java API, a Java-based interface of COMSOL Multiphysics. The developed model is demonstrated with a design hyetograph of 3-month average rainfall intensities of Singapore.

Initial impacts of rain gardens＇ application on water quality and quantity in combined sewer： field-scale experiment

Green infrastructures such as rain gardens can benetit onsite reduction ot stormwater runott, leading to reduced combined sewer overflows. A pilot project was conducted to evaluate the impact of rain gardens on the water quality and volume reduction of storm runoff from urban streets in a combined sewer area. The study took place in a six-block area on South Grand Boulevard in St. Louis, Missouri. The impact was assessed through a comparison between the pre-construction （2011/2012） and the post-construction （2014） phases. Shortly after the rain gardens were installed, the levels of total suspended solids, chloride, total nitrogen, total phosphorous, zinc, and copper increased. The level of mercury was lower than the detection level in both phases. E. coli was the only parameter that showed statistically significant decrease following the installation of rain gardens. The likely reason for initial increase in monitored water quality parameters is that the post-construction sampling began after the rain gardens were constructed but before planting, resulted from soil erosion and wash-out from the mulch. However, the levels of most of water quality parameters decreased in the following time period during the post-construction phase. The study found 76% volume reduction of stormwater runoff following the installation of rain gardens at one of studied sites. Statistical analysis is essential on collected data because of the encountered high variability of measured flows resulted from low flow conditions in studied sewers.

由学生自主营造一个全要素雨水花园的困难与经验

校园营造是指在校园内以师生为主体的参与式设计行动。北京大学自2016年开始尝试学生自主参与校园建设的路径,初步形成了以学生社团为平台、多专业学生合作、多方参与,从被动邀请到主动发起的校园建设模式,探索出由学生主导完成从策划、设计、建造到运营的校园空间更新改造的全程参与经验。以其中一个由学生自主营造的全要素雨水花园的营造过程为例,总结了按照PBL要求的学生自主营造中遇到的困难和经验,详细分析了激发和维护学生自主性的策略,为在建成环境中增建雨水花园和更广泛的自主参与式营造提供了可借鉴的行业经验。

海绵城市源头减排设施运行维护收费标准的研究与建立——以雨水花园为例

在海绵城市建设过程中,海绵城市源头减排设施的运维标准和相应的收费标准是后期维护设施的重要组成内容,目前国内并无相对明确的收费管理措施。选取了海绵城市源头减排设施中最典型的雨水花园为例,结合横琴粤澳深度合作区的海绵城市管养标准,提出了一种不同于现行运维收费标准的方法,旨在明确海绵城市源头减排设施的管养内容和收费依据,保证设施正常、持续发挥作用,同时确保投资的经济合理性,落实海绵城市建设理念。

基于可持续发展的口袋公园雨水花园设计研究

文中以某城市口袋公园雨水花园项目为例,深入探索雨水花园的设计与施工。结果显示,该项目成功利用了150 m^(2)的空间,实现了85%雨水收集率和90%雨水利用率,耗时3 d完成土壤改良工作,将土壤有机质含量提升至3.5%,同时,项目生物多样性指数达到2.8,生态平衡指数达到85%。项目效益超过预期要求,但仍有改进空间,特别是在进一步提高雨水收集率和生态系统优化方面。

LID措施在海绵城市景观设计中的应用

低影响开发(LID)理念是海绵城市的核心要素之一,在海绵城市建设中的措施包括生态植草沟、下凹式绿地、雨水花园、绿色屋顶、地下蓄渗、透水路面等。文章主要从透水铺装、植草沟、雨水花园3方面提出LID措施在市政道路景观设计中的应用研究,并对这些措施下植物的选择提出一定思考。通过实际项目的测试对比得出,当滞留带标准低于10.0mm/min时,道路不存在溢流情况,最大溢流量仅为4.95mm/min,对应的入渗量始终稳定在5.0mm/min以上,可以实现对水资源的有效利用。

防渗型雨水花园在海绵城市建设中的应用

防渗型雨水花园是通过在其底部增设高密度聚乙烯(HDPE)膜防止雨水下渗,设计多层渗透结构和透水盲管,实现雨水净化和收集。文章针对城市内涝和径流污染等问题,分析了防渗型雨水花园的典型应用场景和施工工艺,旨在为后续防渗型海绵城市设施建设提供参考。

基于在线监测的雨水花园系统径流水量控制方法

目前常规的雨水花园系统主要通过搭建绿色屋顶等雨水滞留设施,实现对径流水量的控制,因其缺少对排水管道拓扑结构的分析步骤,导致径流控制效果不佳。针对这一问题,提出基于在线监测的雨水花园系统径流水量控制方法。使用传感设备实现对径流水量的实时监测,并增加蓄存功能;以监测结果为基础,对排水管道拓扑结构差异展开分析,并通过调整模拟降水量、调蓄容积等参数实现对径流水量的控制。结果表明:上述方法可以达成较高的地表径流衰减率,具备良好的径流水量调控能力。

雨水花园在风景园林设计中的应用与优化

雨水花园在风景园林设计中发挥着重要作用,广泛应用于城市公园、居住区和校园景观中,不仅美化环境,还促进雨水资源的有效利用。为进一步提升其生态效益和景观效果,需优化植被选择与配置,确保植物适应性强且具备净化能力;优化结构与功能,确保雨水花园的稳定运行;并引入智能化管理系统,实现实时监测、数据分析和自动调节,提高管理效率。这些优化策略将推动雨水花园在风景园林设计中的可持续发展。

低影响开发在武汉地区中学校园景观设计的应用研究——以武钢三中雨水花园优化设计为例

低影响开发理论已经成为如今城市雨水管道设计中的重要应用基础。而校园景观作为绿地与建筑的重要结合,是与该理论极为匹配的场所。本文希望以武汉地区的中学中心花园为例,探讨低影响开发策略在中学雨水花园设计中所采用的空间与功能相交融的设计模式以及生态与教育相结合的设计目标。并最终将这一模式作为该地区相关改造的典型案例,对更多的校园改造提供建议与借鉴。

海绵城市中雨水花园的建造技术分析——以龙州口袋公园为例

近年来,我国海绵城市建设作为新型的绿色、环保工程已进入快速发展期,海绵城市中雨水花园的建造不仅能有效控制径流污染,还能缓解城市内涝和热岛效应。文章以龙州口袋公园项目为例,对雨水花园碎(砾)石排水层、人工填料层、植被及种植土层、覆盖层和表面蓄水层等各环节的实施进行阐述,总结实践中的经验和教训,为今后海绵城市中雨水花园的建设者提供一定的理论参考。

基于DRAINMOD模型的雨水花园运行效果影响因素

为研究雨水花园对暴雨径流水文调控效果受不同设计参数的影响,在试验研究的基础上,利用排水模型DRAINMOD分析了雨水花园长期运行效果受其蓄水层深度、汇流面积比以及降雨特征等因素的影响。模型测试结果显示,DRAINMOD可以较好地模拟雨水花园内部水文过程;长序列(1951—2007年)模拟结果发现,试验雨水花园对暴雨径流量削减率的年均值为18.5%,经介质净化的水量占雨水径流总量的76.1%;雨水花园蓄水层深度超过某一临界值后对其滞留效果没有影响;汇流面积比增大,排水量和溢流量均增大;在雨水花园内部增加30 cm反硝化作用蓄水层后,排水量下降了19.2%,雨水花园对径流量的削减率提高到33.5%。可见,增加内部蓄水层后雨水花园对水量削减和污染物浓度去除都具有积极作用。

杭州市雨水花园竹类植物资源应用现状与优化策略

竹类植物具有良好的生态效益和极高的美学价值,但目前竹类植物在雨水花园中的相关应用研究基本空白。采用实地调研与数据分析相结合的方法,对杭州市25个雨水花园的竹类植物资源进行分析,包括应用比例、种类组成、生长状况、应用区域和配置模式。结果表明,调研的25个雨水花园中只有5个种植竹类植物,占比为20%。竹类植物种类仅有3种,分别为小琴丝竹(Bambusa multiplex cv.Alphonso-Karri)、箬竹[Indosasa tessellatus(Munro)P.C.Keng]和刚竹(Phyllostachys sulphurea var.viridis R.A.Young),其中小琴丝竹应用最多。应用区域集中在边缘区和缓冲区,蓄水区中没有应用。配置模式主要为丛植和片植。针对杭州市雨水花园竹类植物资源存在应用比例偏低、种类单一、应用区域不够广泛,以及配置模式单调的问题,探讨了雨水花园竹类植物的多样性提升策略、生态适宜性策略,以及种植区域与配置模式拓展策略。研究结果可为雨水花园和海绵城市建设中的竹类植物资源应用拓展和景观多样性提供参考。

湿热地区雨水花园夏季微气候影响效应——基于成都市圣灯公园的实证研究

作为我国理水治国和城市生态转型的重大举措,海绵城市成为解决水资源和热岛等相关问题的重要契机。雨水花园是海绵城市技术措施中非常重要和普遍的一种类型,下垫面、植物设计、地形差异、水体等几个方面与普通绿地存在差异。通过结合实测和模型模拟等方法深入分析雨水花园中下垫面和植物设计在微气候影响方面的差异。既有研究发现,雨水花园下垫面特有的覆盖层、填料层、砾石层以及不同厚度填料层具有不同的蓄水蓄热能力、雨水下渗速率及土壤水分的蒸发强度,从而影响土壤湿度,形成微气候差异,雨水花园下垫面相较普通绿地降温降湿更显著,对相对湿度的影响大,形成的不舒适指数更低。模拟结果显示雨水花园下垫面更厚,降温的效果更明显。在植被方面,当雨水花园与普通绿地植被类型相同时,雨水花园降温的效果优于普通绿地。雨水花园与普通绿地微气候差异与植被乔灌草的搭配类型相关,当植被类型为乔灌草时,雨水花园与普通绿地的温度和相对湿度差值最大,植被类型为草本时,雨水花园与普通绿地的温度、相对湿度差值最小。相应研究可为多功能雨水花园提供理论支撑,并提升海绵设施的科学性,促进海绵城市建设目标和内涵的充分实现。

基于层次分析法的皖南地区雨水花园植物综合评价与选择

对国家海绵城市池州市的12处雨水花园进行现状调查。采用层次分析法,构建雨水花园植物综合评价与选择模型,对27种雨水花园植物从3个约束层和7个标准层进行综合评价分析。结果表明指标中耐水性、耐旱性、净化水质能力以及可观赏性是最重要的四个指标。千屈菜、芦竹等16种植物综合评价等级为一级,是池州市及皖南地区雨水花园首选植物;迎春、山茶等4种植物综合评价等级为二级,可根据雨水花园构造合理选择区域搭配;石竹、海桐等7种植物综合评价等级为三级,是雨水花园建设的慎选植物。