Planning and Design of Beautiful Countryside Based on the Concept of Stormwater Resilience: A Case Study of Shanbei Village, Yunfu City, Guangdong Province

Shanbei Village is a village in Yunfu of Guangdong,which has been seriously affected by flood disasters.In the context of the construction of beautiful countryside,utilizing the concept of resilience stormwater,construction ideas of beautiful countryside of combining the prevention and control of village flood disasters with economic and social development and cultural heritage are proposed.The planning methods of adjusting the planting way of crops,demolition of dwellings in submerged areas and development and utilization of ancient dwellings,sorting out drainage systems and planning“large,medium and small sponges”,and improving the drainage capacity of culverts are summarized.

Laboratory Study on Stormwater Runoff Treatment via Sand-Based Micron-scale Pore Pervious Paver

Stormwater runoff samples from a road in China were collected and analyzed for pH,TSS(total suspended solid),TDS(total dissolved solid),COD(chemical oxygen demand),TP(total phosphorus),TN(total nitrogen),Pb,Al,Zn,Fe,Cd,and Mn.Results showed that the pollutant concentrations from road runoff were relatively high.TSS and COD concentrations exceeded the Class B effluent requirement of the Chinese Standards of Pollutant Discharge from municipal WWTPs(wastewater treatment plants).COD,TP,and TN concentrations exceeded Class V of the Chinese Environmental Quality Standard for Surface Water.TSS,Zn,Fe,and Al concentrations exceeded the USEPA(U.S.Environmental Protection Agency)benchmark values.All these indicated proper runoff treatment to avoid negative impacts on the environment is needed.Metal partitioning analysis was conducted and it showed that Pb,Al,Zn,Fe,and Mn exist mostly in particulate forms in the runoff.Thus,gravitational settlement and filtration can still be cost-effective methods for removing most of these metals.Runoff samples were treated through two bench-scale laboratory set-ups,composed of micron-scale pore pervious paver systems and subsoil.The average removal rates of TSS,TP,and TN were 95.2%,81.8%,64.1%,and 64.4%,respectively.The removal rates of Pb,Al,Zn,Fe,and Cd also reached 50%-99.2%.The tested sand-based pervious paver has micron-scale pores with good filtration potential.The system can effectively reduce stormwater runoff pollution,thereby reducing the potential for groundwater pollution.In addition,residues and sediments collected from the surfaces of the pervious pavers were also tested.The metallic constituents in the residues and sediments were correlated to these in the runoff.Pb and Cr were low in the residues,but Zn exceeded the Class A limit of the Chinese Control Standard of Pollutants in Sludge for Agricultural Applications.Thus,proper disposal of the solid wastes generated from the pavers is also to be further investigated.

Application of Urban Green Stormwater Infrastructure in Wetland Park Construction

The positive role of urban green stormwater infrastructure(GIS)and wetland park construction in the process of“sponge city”construction is analyzed by expounding the connotation and problems of“sponge city”construction.Through the analysis of relevant cases,the realization approaches of combing different types of GIS with wetland park landscape design are interpreted,and it is pointed out that different types of GIS can guide the further practice of“sponge city”construction.

Stormwater Quality Characteristics and Reuse Analysis of Different Underlying Surfaces at Wanzhou North Station

In response to the water shortage in Wanzhou North Station(WNS),the authors investigated the stormwater quality characteristics with different underlying surfaces of WNS and carried out stormwater reuse analysis in conjunction with the InfoWorks ICM model.The results show that during heavy,torrential,and moderate rainfall,the road stormwater runoff has the highest concentrations of pollutants,with an average EMC(event mean concentration)value of 206 mg/L for COD.For the square runoff,the average EMC values of COD,SS,TN,and TP are 108 mg/L,395 mg/L,2.113 mg/L,and 0.128 mg/L,in comparison,the average EMC values of the corresponding indexes for the roof runoff are 65 mg/L,212 mg/L,1.449 mg/L,and 0.086 mg/L,respectively,demonstrating their potential for reuse.The R2(coefficient of determination)of SS and COD in both roof and square runoff are greater than 0.85,with a good correlation,indicating that SS removal is the key to stormwater purification.InfoWorks ICM analysis shows that the recyclable volume of rainwater from WNS in 2018 is 29,410 m3,accounting for 61.8%of the total annual rainfall.This study is expected to provide an ideal reference for the stormwater management of public buildings in mountainous areas.

Influence of Physical and Chemical Parameters on the Treatment of Heavy Metals in Polluted Stormwater Using Zeolite—A Review

Zeolite-based technology can provide a cost effective solution for stormwater treatment for the removal of toxic heavy metals under increasing demand of safe water from alternative sources. This paper reviews the currently available knowledge relating to the effect of properties of zeolites such as pore size, surface area and Si:Al ratio and the physico-chemical conditions of the system such as pH, temperature, initial metal concentration and zeolite concentration on heavy metal removal performance. The primary aims are, to consolidate available knowledge and identify knowledge gaps. It was established that an in-depth understanding of operational issues such as, diffusion of metal ions into the zeolite pore structure, pore clogging, zeolite surface coverage by particulates in stormwater as well as the effect of pH on stormwater quality in the presence of zeolites is essential for developing a zeolite-based technology for the treatment of polluted stormwater. The optimum zeolite concentration to treat typical volumes of stormwater and initial heavy metal concentrations in stormwater should also be considered as operational issues in this regard. Additionally, leaching of aluminium and sodium ions from the zeolite structure to solution were identified as key issues requiring further research in the effort to develop cost effective solutions for the removal of heavy metals from stormwater.

Strategies for Enhancing the Efficiency of Bioretention Swales and Basins for Urban Stormwater Management in Temperate Region

Among various schemes to reuse and recycle the limited urban fresh water resources, sustainable urban stormwater management, such as water sensitive urban design and rainwater harvesting, has been recognized as one of the most efficient and economically viable approaches. Storm runoff shall be treated as close as possible to its source before it is reused or discharged into public drainage network or receiving waters to enhance the water environment quality. Bioretention swale/basin, which has been commonly applied to treat runoff from roads, car parks, cyclist and pedestrian paths, rooftops, etc., is recognized to be the most efficient and aesthetic pleasing way to harvest rainwater in urban settings, and other longish shape runoff catchment area. This paper studied over 10 bioretention swales/basins applications in temperate region worldwide covering China, Germany, Norway, Austria, USA, and Australia. Key steps in bioretention swale/basin design and implementation in temperate region were investigated, such as strategic bioretention scheme selection, flow conveyance and hydraulic capacity design, filtering media profile, vegetation scheme selection and maintenance scheme, and suggestion and key design parameters. The critical path and parameters of bioretention swale/basin design which enhanced the effectiveness and efficiency of its application for rainwater harvesting in temperate regions were derived.

On-site stormwater detention for Australian development projects: Does it meet frequent flow management objectives?

On-site stormwater detention (OSD) is a conventional component of urban drainage systems, designed with the intention of mitigating the increase to peak discharge of stormwater runoff that inevitably results from urbanization. In Australia, singular temporal patterns for design storms have governed the inputs of hydrograph generation and in turn the design process of OSD for the last three decades. This paper raises the concern that many existing OSD systems designed using the singular temporal pattern for design storms may not be achieving their stated objectives when they are assessed against a variety of alternative temporal patterns. The performance of twenty real OSD systems was investigated using two methods:(1) ensembles of design temporal patterns prescribed in the latest version of Australian Rainfall and Runoff, and (2) real recorded rainfall data taken from pluviograph stations modeled with continuous simulation. It is shown conclusively that the use of singular temporal patterns is ineffective in providing assurance that an OSD will mitigate the increase to peak discharge for all possible storm events. Ensemble analysis is shown to provide improved results. However, it also falls short of providing any guarantee in the face of naturally occurring rainfall.

Purification of Stormwater Using Sand Filter

Rain water is an important source to feed the groundwater aquifer, whether directly or by harvesting and recharging. The importance of purification is for reducing the risk of pollutants from recharging runoff rainwater. The use of sand filter as a technique considered not expensive and commonly used for removing contaminants from water and wastewater treatment industries. The methodology used laboratory testing, by designing and constructing pilot plant to experiment the sand filter for purification, and made simulation for the infiltration of storm water through sand filter of 2 meters depth, in order to find the relationship between the depth on one hand, and the removal of suspended solids and fecal coliforms bacteria on the other hand, to know the effective depth that gets the purification. The research results during three days of infiltration show that the sand filter can remove fecal coliforms bacteria at a depth of 150 cm, and provide purified water with a concentration of suspended solids less than 20 mg/liter at a depth of 75 cm.

Research on Stormwater Management of Cultural Heritage Ilmpark in Weimar Germany Based on Urban Resilience

With the development of cities, problems like natural and social disasters appeared more and more frequently. For example, rapid urbanization and climate change have caused both increasing flood probability and the severity of flooding. Consequently, there is a need for all cities to develop new strategies to maintain their vitality in numerous challenges and crises. This paper in the first place reviews the concept and research fields of urban resilience;besides, according to the characteristics of the Ilmpark situated in Weimar, This paper analyzes the necessity and potential on stormwater management of this area and then it concludes the alternative strategies of improvement based on the theory of urban resilience.

Low-Cost Stormwater Filtration System to Improve Urban Water Quality: The Case of Addis Ababa, Ethiopia

Urbanization in developing countries often negatively impacts water re-sources by polluting surface waters. Addis Ababa, Ethiopia, is currently experiencing rapid urbanization accompanied by significant water shortages, unmanaged stormwater, and increasing river water pollution. To supplement the need for non-potable water and address stormwater runoff pollution, we constructed a low cost stormwater filtration system. The filtration system is comprised of a sedimentation area followed by three gravel grain sizes arranged horizontally from coarse to medium to fine filter media. We compared the quality of pretreatment water with post-treatment water by measuring physicochemical parameters, heavy metals and nutrients. We found that the filtration system reduced turbidity by 87%, TSS by 80%, Cu by 87% and Zn by 90%. Further, it positively increased the concentration of DO by 42%. However, the filtration system did not remove nitrates and nitrites. Implementing this system at outfalls in the rapidly expanding condominium housing areas can increase residents’ supply of non-potable water and reduce the amount of polluted stormwater entering nearby streams and rivers.

Phenoxyacid Herbicides in Stormwater Retention Ponds: Urban Inputs

Surface water runoff from urban centers is a major source of environmental pollution which impacts water quality in downstream aquatic habitats. Phenoxyacid herbicides are some of the most widely globally used herbicides in agriculture and urban environments for weed control. Their transformation products which in- clude chlorophenols can be more toxic than the active ingredients. We used LC/MS/MS to analyzed simul- taneously these acid herbicides and their transformation products in stormwater retention ponds taken from an urban environment to examine the occurrence and potential release of these herbicides from urban inputs into downstream waters. 2,4-dichlorophenoxyacetic acid and mecoprop were detected in all samples col- lected from the ponds and at the highest concentrations, while 2-methyl-4-chlorophenoxyacetic acid was de- tected only in spring and summer. Two transformation products, 4-chloro-2-methylphenol and 2,4-di- chlorophenol were detected in samples primarily at inlet locations on the ponds indicating that degradation had occurred in surface soils prior to surface water runoff.

Stormwater Management Practices and Green-Blue Infrastructure in Urban Areas: an Overview

Water quality,flooding risk,and water consumption in urban areas are emerging issues.Urban impervious surfaces increase stormwater runoff,affecting ecosystems and leading to hydrogeological instability and flooding risk.Sustainable urban design strategies can contribute to counteract the negative impact of anthropic activities both at city-scale and global scale.Green and Blue Infrastructure(GBI)approaches,in particular,are an alternative to stormwater traditional management.In Europe,Sustainable Drainage System implementation copes with impervious surfaces to achieve water quality,amenity,and biodiversity increase.Best Management Practices,developed mainly in the USA,focus on specific measures for sustainable stormwater treatment.Water Sensitive Urban Design,spread in Australia and England,also aims to minimise the impact of developed areas preventing flood risk,limiting water consumption and enhancing environmental quality.In the USA and Canada,Low Impact Development offers design strategies to manage runoff and deliver structural practices to mimic predevelopment processes of infiltration,filtration and detention.

Applying the Parameter“Irreducible Concentration”in Modelling of Stormwater Treatment Facilities

To design stormwater treatment facilities (STFs), we recommend the use of a model that should include the calculation of runoff quality, to be based on a detailed land use specification, include site-specific design parameters, calculated outflow concentrations and loads of specified pollutants of relevance for the receiving water. This study compiles minimum outflow concentrations from stormwater databases of different types of STFs (e.g. swales, wet ponds, wetlands, biofilters and underground retention basins with filters). These data are used for the suggested values of specific “irreducible concentrations” (Cirr). Suggested Cirr for phosphorus (P) varies from 20-82 μg/L depending on facility type, for copper (Cu) 1.1-3.7 g/L, for zinc (Zn) 2.0-17 μg/L and for total suspended solids (TSS) 2,900-5,700 μg/L. Corresponding data for 70 substances are compiled in the StormTac database and employed in the model StormTac Web. Cirr has significant impact regarding the choice of facility type and its calculated dimensions. This design parameter and the calculated outflow concentrations can be used to investigate the need for combined serial facilities or complemented design elements with more planted vegetation or installed filters. Such elements can be required to decrease Cirr and thereby reach project specific limit outflow concentrations and loads.

Urban stormwater disinfection, quality variability during storage and influence on the freshwater algae: Implications for reuse safety

Stormwater reuse is one of the most important ways to mitigate water resource shortage.However,urban stormwater contains many bacteria species,which threaten the reuse safety.Therefore,stormwater disinfection is highly needed.Although disinfection has been widely conducted in the drinking water and reclaimed water,it is rarely carried out for stormwater.This study collected the roof stormwater and undertook chlorination disinfection.Two typical bacteria,Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)were selected in this study to investigate the disinfection efficiency.It is found that bacteria species present in the stormwater had an important influence on disinfection efficiency while the original stormwater quality did not show an obvious affect.However,when the disinfected stormwater was stored,the stormwater quality was highly variable during its storage process and the variability was affected by bacteria species.The S.aureus containing stormwater showed a high variability of quality and S.aureus significantly regrew.However,the E.coli containing stormwater quality had a relatively low variability and E.coli did not significantly regrew.Additionally,it is noted that after storage,the dissolved form of stormwater was more positive to the freshwater algae’s growth while the particulate form(including bacteria and other particulate matters)was less.This implies that a further treatment such as filtration is needed before the stored stormwater is recharged into receiving waters in order to remove particulate forms.These research outcomes can provide useful insight to effective stormwater disinfection and ensure reuse safety.

Abundance,spatial distribution,and physical characteristics of microplastics in stormwater detention ponds

Despite extensive research on microplastics (MP) in marine environments, little is known about MP abundance and transport in terrestrial systems. There is, therefore, still little understanding of the main mechanisms driving the substantial transport of MP across different environmental compartments. Storm events can transport MP beyond boundaries, such as from the land to groundwater or the ocean, as has already been discovered for organic carbon transport. Urban stormwater detention ponds are suitable environments to study the impact of stormwater on the environmental fate and transport of MP. Herein, we investigate the longitudinal and vertical distribution of MP within two detention ponds with different physical characteristics. Soil samples were collected at various locations and from multiple depths (surface and subsurface layers) for measuring MP concentrations using fluorescence microscopy. Our findings show that MP are retained more near the inlet of the ponds, and MP of larger sizes were found more abundantly near inlets than outlets. We also found that MP mass and sizes decrease from surface soil to subsurface soil. In the pond, where vegetation (grass root network) was more considerable, MP were found more evenly distributed along the depth. In terms of shape, the fragments were the most abundant MP shape.

Green stormwater infrastructure eco-planning and development on the regional scale： a case study of Shanghai Lingang New City, East China

Urban underlying surface has been greatly changed with rapid urbanization, considered to be one of the major causes for the destruction of urban natural hydrological processes. This has imposed a huge challenge for stormwater management in cities. There has been a shift from gray water management to green stormwater management thinking. The green stormwater infrastructure （GSI） is regarded as an effective and cost-efficient stormwater management eco-landscape approach. China＇s GSI practice and the development of its theoretical framework are still in the initial stage. This paper presents an innovative framework for stormwater management, integrating green stormwater infrastructure and landscape security patterns on a regional scale based on an urban master plan. The core concept of green stormwater infrastructure eco-planning is to form an interconnected GSI network （i.e., stormwater management landscape security pattern） which consists of the location, portion, size, layout, and structure of GSI so as to efficiently safeguard natural hydrological processes. Shanghai Lin- gang New City, a satellite new town of Shanghai, China was selected as a case study for GSI studies. Simulation analyses of hydrological processes were carried out to identify the critical significant landscape nodes in the high- priority watersheds for stormwater management. GSI should be planned and implemented in these identified landscape nodes. The comprehensive stormwater manage- ment landscape security pattern of Shanghai Lingang New City is designed with consideration of flood control, stormwater control, runoff reduction, water quality protec- tion, and rainwater utilization objectives which couldprovide guidelines for smart growth and sustainable development of this city.

Pollutant concentrations and pollution loads in stormwater runoff from different land uses in Chongqing

To investigate the distribution of pollutant concentrations and pollution loads in stormwater runoff in Chongqing,six typical land use types were selected and studied from August 2009 to September 2011.Statistical analysis on the distribution of pollutant concentrations in all water samples shows that pollutant concentrations fluctuate greatly in rainfall-runoff,and the concentrations of the same pollutant also vary greatly in different rainfall events.In addition,it indicates that the event mean concentrations （EMCs） of total suspended solids （TSS） and chemical oxygen demand （COD） from urban traffic roads （UTR） are significantly higher than those from residential roads （RR）,commercial areas （CA）,concrete roofs （CR）,tile roofs （TRoof）,and campus catchment areas （CCA）;and the EMCs of total phosphorus （TP） and NH3-N from UTR and CA are 2.35-5 and 3 times of the class-III standard values specified in the Environmental Quality Standards for Surface Water （GB 3838-2002）.The EMCs of Fe,Pb and Cd are also much higher than the class-III standard values.The analysis of pollution load producing coefficients （PLPC） reveals that the main pollution source of TSS,COD and TP is UTR.The analysis of correlations between rainfall factors and EMCs/PLPC indicates that rainfall duration is correlated with EMCs/PLPC of TSS for TRoof and TP for UTR,while rainfall intensity is correlated with EMCs/PLPC of TP for both CR and CCA.The results of this study provide a reference for better management of non-point source pollution in urban regions.

Integral stormwater management master plan and design in an ecological community

Urban stormwater runoff nearly discharges directly into bodies of water through gray infrastructure in China, such as sewers, impermeable ditches, and pump stations. As urban flooding, water shortage, and other environment problems become serious, integrated water environment management is becoming increasingly complex and challenging. At more than 200 ha, the Oriental Sun City community is a large retirement community located in the eastern side of Beijing. During the beginning of its construction, the project faced a series of serious water environment crises such as eutrophication, flood risk, water shortage, and high maintenance costs. To address these issues, an integral storrnwater management master plan was developed based on the concept of low impact development （LID）. A large number of LID and green stormwater infrastructure （GSI） approaches were designed and applied in the community to replace traditional stormwater drainage systems completely. These approaches mainly included bioretention （which captured nearly 85th percentile volume of the annual runoff in the site, nearly 5.4 x 10^5 m3 annually）, swales （which functioned as a substitute for traditional stormwater pipes）, waterscapes, and stormwater wetlands. Finally, a stormwater system plan was proposed by integrating with the gray water system, landscape planning, an architectural master plan, and related consultations that supported the entire construction period. After more than 10 years of planning, designing, construction, and operation, Oriental Sun City has become one of the earliest modem large-scale LID communities in China. Moreover, the project not only addressed the crisis efficiently and effectively, but also yielded economic and ecological benefits.

Surface clogging process modeling of suspended solids during urban stormwater aquifer recharge

Aquifer recharge, which uses urban stormwater, is an effective technique to control the negative effects of groundwater overexploitation, while clogging problems in infiltration systems remain the key restricting factor in broadening its practice. Quantitative understanding of the clogging process is still very poor. A laboratory study was conducted to understand surface physical clogging processes, with the primary aim of developing a model for predicting suspended solid clogging processes before aquifer recharge projects start. The experiments investigated the clogging characteristics of different suspended solid sizes in recharge water by using a series of one-dimensional fine quartz sand columns. The results showed that the smaller the suspended particles in recharge water, the farther the distance of movement and the larger the scope of clogging in porous media. Clogging extents in fine sand were 1 cm, for suspended particle size ranging from 0.075 to 0.0385 mm, and 2 cm, for particles less than 0.0385 mm. In addition, clogging development occurred more rapidly for smaller suspended solid particles. It took 48, 42, and 36 hr respectively, for large-, medium-, and small-sized particles to reach pre-determined clogging standards. An empirical formula and iteration model for the surface clogging evolution process were derived. The verification results obtained from stormwater recharge into fine sand demonstrated that the model could reflect the real laws of the surface clogging process.