Sustainable Stormwater Management Research Articles

A holistic analysis of Chinese sponge city cases by region: Using PLS-SEM models to understand key factors impacting LID performance

Sponge city is a national sustainable stormwater management program proposed by the Chinese government to deal with urban water issues (e.g., flooding, poor water quality) brought on by climate change and urbanization. Various strategies for sponge city construction are required since environmental constraints differ regionally across the country. To identify regional variations, reveal the inner links between externalities and design elements in sponge city construction, and offer practical suggestions, efforts in two directions are made based on the data of 68 sponge city cases around China: 1) discussing design parameters of four Low Impact Development (LID) facilities, including bioretention cell, permeable pavement, grass swale, and sunken green space, under four regionalization maps of hydrologic, climatic, landform and soil texture factors, and 2) building a holistic Partial Least Squares-Structural Equation Modelling (PLS-SEM) model illustrating the relationship between local characteristics, LID system design, and LID system performance in sponge city construction. The results show that: 1) rainfall and landform factor have great impact on LID facilities design, as their depths tend to be higher in water rich areas and coastal areas. 2) LID types and areas are positively influenced (+0.745) by the total area and permeable portion of a project, while the LID system performance (water quantity and quality control) is negatively impacted (−0.407) by the rainfall amount and clay fraction. 3) comprehensive LIDs choice and design instead of single LID facility shows more significant effect on improving LID system performance. It is recommended to establish different design standards and assessment indexing systems tailored to local environment when constructing sponge city projects.

Innovative and Reliable Assessment of Polluted Stormwater Runoff for Effective Stormwater Management

This article examines the pollution dynamics in urban wet-weather runoff, addressing the statistical characterization and systematic classification of water quality characteristics as key aspects of sustainable and effective urban stormwater quality control and treatment measures. A reliable first flush methodology is applied to discrete water quality data of different pollution parameters from an Italian database for the identification of the Bivio Vela catchment’s representative evolution of mean concentrations and the assessment of the required runoff volume to reduce stormwater pollutant concentrations to background levels. A comparison is carried out between results from two catchments with different land use types (industrial versus residential) and the complexity of the sewerage system, highlighting challenges in tracking pollution trends and delineating peculiar dynamics of different quality parameters in a specific geographic context. Despite appreciably different pollutant dynamics, both catchments achieve background levels for all the examined parameters after 6 mm runoff. The outcome of the analysis has clear implications for the design approach of sustainable stormwater management practices.

Assessment of the Feasibility of Permeable Pavement for Sustainable Stormwater Management Using SWMM

Assessment of the Feasibility of Permeable Pavement for Sustainable Stormwater Management Using SWMM

Assessment of the Implementation of Sustainable Stormwater Management Practices in Asian Countries

Numerous efforts have been undertaken by Asian countries to mitigate the adverse effects of urbanization on stormwater management. However, traditional stormwater systems have become overwhelmed due to extensive development, resulting in excessive runoff and frequent floods. As a result, it is crucial to urgently adopt sustainable stormwater management practices (SSMPs) to effectively control water quantity and quality. The goal of this study is to assess the viewpoints of stormwater practitioners regarding green roofs, rainwater harvesting systems (RHS), grass swales, rain garden/bioretention systems, and porous pavement using a SWOT analysis. This was accomplished by distributing questionnaires and evaluating previous studies. The survey showed that participants mostly agreed with the strengths, weaknesses, opportunities, and threats factors related to the chosen SSMPs. Overall, the respondents favoured the implementation of green roofs and grass swales. Further assessments were conducted on these practices in other aspects, confirming that green roofs are the most preferable SSMP for implementation in Asian countries.

GREEN INFRASTRUCTURE FOR PROTECTING SHIRAZ'S HISTORIC URBAN FABRIC FROM FLOODING

Shiraz, a city known for its rich historical urban fabric, faces increasing challenges posed by climate change and extreme weather events, particularly floods. The rapid urbanization and limited stormwater management infrastructure have exacerbated the vulnerability of the city's historic areas to flooding. Due to the registration of 360 km of Shiraz historical fabric in the national register in 2023, the importance of planning to safeguard this precious heritage has become twice as crucial. This study explores the potential of urban green spaces as a sustainable approach to mitigate flood impacts on Shiraz's historic urban fabric. Through a comprehensive analysis of flood patterns, urban green spaces, and historic buildings, this research aims to identify the most flood-prone areas and assess the effectiveness of existing green spaces in minimizing flood risks. The study also evaluates the role of vegetation and permeable surfaces in stormwater management to reduce floodwater runoff and its impact on historical structures. The findings reveal that strategically designed and maintained urban green spaces can act as natural flood buffers, helping to regulate water flow, reduce surface runoff, and minimize flood-induced damage to historic buildings. By integrating green spaces into urban planning, policymakers can enhance the city's resilience to floods and preserve the unique character and heritage of Shiraz's historic urban fabric. This study advocates for incorporating green infrastructure and sustainable stormwater management practices as integral to urban planning strategies. By embracing nature-based solutions, Shiraz can safeguard its historical treasures and foster a more sustainable and resilient urban environment for current and future generations. This research aimed to assess the implications of reducing urban green spaces, particularly in the green belt surrounding Shiraz's historic urban fabric and Snag-e-Siah neighborhood, on the vulnerability of historical sites to flood damage and potential demolition. With the utilization of urban green spaces, flood damage to Shiraz's built heritage was investigated in this study using both quantitative and qualitative methods simultaneously. The study results showed that the reduction of urban green infrastructure significantly increased the damage caused by floods in the historical area of Shiraz.

Maintenance of low impact development facilities: A case study of pilot sponge cities in China

The concept low impact development (LID) has been provided for over five decades for achieving sustainable stormwater management. However, once installed, LID facilities often suffer from a lack of maintenance, resulting in impaired functionality and substantial wastage of financial resource. Since 2014, many LID facilities have been constructed in Chinese pilot sponge cities. However, to date, there is little knowledge about the post-construction status of these LID facilities. In response, we investigated the current status quo, common problems needing maintenance, and residents’ attitudes towards maintenance of LID facilities. The results showed that, among 467 bio-retention facilities in three surveyed pilot sponge cities, approximately one third of the bio-retention facilities were in a good state; However, more than one thirds are facing issues of decreasing vegetation coverage rate, a deteriorating vegetation growth situation, and the slight silting or blocking of water inlets or overflow ports. Thus, regular maintenance is necessary, but the starting maintenance time can go through in the fifth year after construction. Unfortunately, public participation on the maintenance would be difficult. Even those respondents who willing to pay for the maintenance fee or possessing previous knowledge exhibit reluctance to engage in maintenance practices. The paper provides decision makers with a comprehensive overview of the status quo and common maintenance problems associated with LID facilities in the Chinese pilot sponge cities. It can also equip governments with insights to effectively address maintenance and management issues related to LID facilities.

Exploring community perceptions and engagement of nature-based solutions: The case of Ningbo, a Chinese coastal sponge city

Sustainable stormwater management facilities such as strip bioretention, effectively improve the urban landscape's urban stormwater quality and aesthetics. The progress of Nature-Based Solutions (NBS) and Blue-Green Developments such as the Sponge City Program (SCP) in Chinese cities, is significantly delivering multiple benefits to address urban water, climate and ecosystem services. These practices are transforming the urban environmental context and enhancing the wider aspects of social-environmental interactions and participation. This study will particularly focus on investigating the SCP practices implemented for several years in Ningbo, a selected Sponge pilot city on the east coast of China. There is currently a lack of substantial findings from the perspective of communities towards NBS in China or an understanding of the importance of participation and engagement processes in Sponge or NBS infrastructure in Chinese cities. Through an in-depth semi-structured interview (n = 34), this study will elucidate the previous developments, current challenges and future delivery of constructed NBS infrastructure (e.g. artificial wetland). This article will undertake a detailed investigation of public perceptions, channels of learning, and opportunities for further participation and engagement in the case of Ningbo. In this study, we found that the perception and participation are likely to improve significantly in the future and that public education about SCP practices would foster closer human-nature stormwater connections and co-production to deliver better NBS practices.

The Relationship between Urban Morphology on Impervious Surface Coverage in High-Density Areas - The HK Northern Metropolitan Area as a Case Study

Impervious surfaces are one of the key factors that impact stormwater management, especially for high density urban areas. This study explores the relationship between urban morphology and impervious surface coverage in high-density areas to address stormwater management challenges. Focusing on Hong Kong Northern Metropolitan Area as a case study, the research examines land use planning and diverse urban morphologies to understand the impact of impervious surfaces on stormwater runoff. From land use planning to analyzing different urban morphologies, the study elucidates the amount and distribution of impervious surfaces and their impact on stormwater runoff management in urban design. Findings provide valuable insights for urban design practices, enabling targeted strategies for sustainable stormwater management in high-density areas. By understanding the relationship between Hong Kong's context-specific urban form and properties of impervious surface /properties, targeted strategies can be developed to address the unique challenges, especially in the context of planning for the latest urban growth. Promoting the use of green infrastructure and nature-based solutions, the research contributes to the knowledge on urban stormwater management, emphasizing resilience in Hong Kong’s new urban environment.

Landscape and Horticultural Fertigation Using Roof-Derived Storm Water: The Potential Multiple Benefits of Blue Green Roof Installations

A contribution to the sustainable management of storm water is the use of sustainable drainage (SuDS)-derived water as an unconventional source for irrigation. If storm-water runoff contains dissolved nutrients in excess of those found in conventional irrigation, reusing this water can contribute to the nutrient demands of horticulture or landscaping, which is known as “fertigation”. Green roofs are SuDS devices, and those with below-substrate water storage, blue green roofs, can be additional water sources. The nutrients released from a roof-substrate-growing medium could contribute to the growth of crop and landscape plants, but materials from blue green roofs must not release residues harmful to fertigated plants or receiving soils. This plant growth experiment examined the effects of water from a blue green roof on plant growth and health and the effects on soil and roof-harvested water when functioning as a nutrient-rich irrigation source. Tomatoes and ryegrass were used as examples of horticultural and landscaping plants, respectively. Blue green roof water was compared with potable water irrigation. The blue-green-roof-derived water provided a distinct growth advantage for tomatoes and lower sodium in fruits than tap water, at 285 mg/kg and 636 mg/kg, respectively. For ryegrass, the differences were minimal, but there was no disadvantage to using roof water for fertigation. Following three years of a blue green roof’s operational life, export of inorganic nutrients from the roof, local storage, and then application to plants were effective in contributing additional fertiliser.

Composition of soil bacterial communities associated with urban stormwater detention basins and their predicted functional roles in N cycle.

Stormwater detention basins serve as vital components in mitigating the adverse effects of urban runoff, and investigating the microbial dynamics within these systems is crucial for enhancing their performance and pollutant removal capabilities. The aim of this study was to examine and compare the soil bacterial communities in two stormwater detention basins located on the Edwards Aquifer in Bexar County, Texas, USA, and evaluate how soil physiochemical properties may affect them. Each basin soil was sampled in two different seasons at varying depths and the structure of microbial communities was examined using paired end Illumina sequencing using V3 and V4 region of 16S rRNA gene. PICRUSt2 was used to predict functional genes in the nitrogen cycle. In addition, soil physicochemical properties such as pH, carbon, nitrogen, and phosphorus and particle size were examined. A beta diversity analysis revealed that basins had distinctive microbial communities. Additionally, soil particle size, phosphorus and ammonia significantly correlated with some of the dominant phyla in the basins. Proteobacteria and Acidobacteria showed a positive correlation with the relative abundances of nitrogen-cycling genes, while Actinobacteria showed a negative correlation. This study evaluated the associations between soil physicochemical properties and microbial community dynamics in stormwater basins. The study also predicts the relative abundance of nitrogen cycling genes, suggesting shared functional traits within microbial communities. The findings have implications for understanding the potential role of microbial communities in nitrogen cycling processes and contribute to developing sustainable stormwater management strategies and protecting water quality in urban areas.

A New Method for Selecting the Geometry of Systems for Surface Infiltration of Stormwater with Retention

The application of infiltration basins and tanks is one of the primary means of sustainable stormwater management. However, the methods currently used to size these facilities do not take into account a number of parameters that have a significant impact on their required capacity. In light of this, the aim of this research was to develop a new method for selecting the geometry of the infiltration basins and tanks. Its application in the initial phase of designing stormwater management systems will allow assessing the validity of using such facilities in a given catchment area. This paper also presents the results of local and global sensitivity analyses examining how changes in individual design parameters influence stormwater infiltration facilities. The effectiveness of the developed model was evaluated through the example of a real urban catchment. The study was based on a hydrodynamic analysis of more than 3000 model catchments. The research plan was developed using Statistica software. On the other hand, the analysis of the results of hydrodynamic simulations was made possible through the use of artificial neural networks designed using the Python programming language. The research also confirmed that parameters such as the total catchment area, the percent of impervious area, and the type of soil within the catchment are crucial in the design process of these facilities. The results of this research can be considered when designing infiltration basins and tanks under Polish conditions. The described algorithm can also be used by other researchers to develop similar models based on different rainfall data. This will contribute to increasing the safety of urban infrastructure.

Evaluation of the Implementation of Sustainable Stormwater Management Practices for Landed Residential Areas: A Case Study in Malaysia

In Malaysia, the Stormwater Management Manual for Malaysia (Manual Saliran Mesra Alam or MSMA) was introduced to manage stormwater and solve water-related problems. However, massive development caused the conventional stormwater system to be unable to cater to the excessive runoff and led to flooding, also affecting residential areas. This shows that there is an urgent requirement for a sustainable stormwater management practice (SSMP) in residential areas. This study is conducted to evaluate stormwater practitioners’ opinions on the proposed SSMPs, including green roofs, rain gardens/bioretention systems, and porous pavements, based on Strength, Weakness, Opportunity, and Threat (SWOT) factors through surveys and correlation analysis. The questionnaire was distributed to 14 branches of the Department of Irrigation and Drainage (DID), 14 branches of the City Council, and 28 selected private engineering companies. In total, 118 respondents were targeted to obtain their perspectives on the SWOT factors for each selected SSMP according to the Likert scale. The survey showed that the respondents agreed with most of the SWOT factors on the selected SSMPs. The results of the distributed questionnaire were used as the data for the correlation analysis. The analysis indicated that green roofs, rain gardens/bioretention systems, and porous pavements have a strong positive relationship, with a p-value of less than 0.05 for the Strength and Opportunity factors, and a weak positive relationship, with a p-value of more than 0.05 for the Weakness and Threat factors. This shows that the proposed SSMPs are suitable to implement in residential areas. Observations were conducted to obtain the residents’ opinions on the performance of stormwater management in their residential areas and to evaluate the suitability of the proposed SSMPs to be implemented in the observed areas. Based on the observations, it can be concluded that only rain gardens/bioretention systems and porous pavements are suitable when compared to green roofs. An interview session was conducted with practitioners in stormwater management to gain their opinions on the studies and the proposed SSMPs. The interviewees agreed with the issues and that the SSMPs should be implemented in landed residential areas.

Rooftop water harvesting for managed aquifer recharge and flood mitigation in tropical cities: Towards a strategy of co-benefit evaluations in João Pessoa, northeast Brazil

Intense urbanisation in many coastal areas has led to intensification of groundwater consumption, while reducing permeable areas and increasing the frequency and magnitude of flooding. Among the potential strategies to compensate for these adverse effects, which are expected to become worse as a result of climate change, rooftop rainwater harvesting (RWH) in combination with managed aquifer recharge (MAR), may be indicated. This work investigated the performance of different configurations of such a system, tested as a twofold sustainable stormwater and domestic water management tool in a tropical metropole (João Pessoa, Brazil). This area located over a sedimentary aquifer system illustrates the water security challenges of densely urbanised areas in southern cities. To that end, several configurations of rooftop catchments and storage volumes were evaluated, by simulating a MAR-RWH system connected to the regional unconfined aquifer (Barreiras Formation) through a 6″ diameter injection well. Rainfall-runoff-recharge processes and water balances were simulated using monitored high-temporal resolution rainfall data. The results showed that catchments ranging from 180 to 810 m2, connected to tanks from 0.5 to 30.0 m³, are the optimal solutions in terms of efficient rainwater retention and peak flow reduction. These solutions provided mean annual estimates of aquifer recharge between 57 and 255 m³/yr from 2004 to 2019. The results of this study highlight the opportunity for MAR schemes to reconcile stormwater management and water supply goals.

Assessing urban flooding risk in response to climate change and urbanization based on shared socio-economic pathways

Global climate change and rapid urbanization, mainly driven by anthropogenic activities, lead to urban flood vulnerability and uncertainty in sustainable stormwater management. This study projected the temporal and spatial variation in urban flood susceptibility during the period 2020–2050 on the basis of shared socioeconomic pathways (SSPs). A case study in Guangdong-Hong Kong-Macao Greater Bay Area (GBA) was conducted for verifying the feasibility and applicability of this approach. GBA is predicted to encounter the increase in extreme precipitation with high intensity and frequency, along with rapid expansion of constructed areas, resulting in exacerbating of urban flood susceptibility. The areas with medium and high flood susceptibility will be expected to increase continuously from 2020 to 2050, by 9.5 %, 12.0 %, and 14.4 % under SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, respectively. In terms of the assessment of spatial-temporal flooding pattern, the areas with high flood susceptibility are overlapped with that in the populated urban center in GBA, surrounding the existing risk areas, which is consistent with the tendency of construction land expansion. The approach in the present study will provide comprehensive insights into the reliable and accurate assessment of urban flooding susceptibility in response to climate change and urbanization.

Hydrologic and water quality modelling of bioretention columns in cold regions

AbstractBioretention is widely used in urban sustainable stormwater management; however, limited numerical research has been conducted on its performance in cold regions, particularly for winter snowmelt, spring runoff and summer large storms (>50 mm) for urban flood mitigation. In this study, HYDRUS 1D was used to explore these knowledge gaps. The model was comprehensively calibrated and validated against 2‐year hydrologic and water quality data of four bioretention columns with different designs under lab‐simulated cold region conditions. The Morris method was used to measure the sensitivity and interaction of the calibrated hydraulic parameters. The model revealed that the effective hydraulic conductivity (KS) values of the soil media were similar for winter snowmelt and spring runoff when the soil temperature was around −0.5°C. Preferential flow is likely to occur in soil media during winter or spring in cold regions. The summer modelling showed that bioretention could substantially reduce peak flow, ponding depth and duration for large storm events (even for a 1:100 local storm with 83.4 mm in 4 h). The water quality modelling confirmed experimental results that the bioretention effectively removed phosphate and ammonium but had leaching issues for chloride and nitrate. Finally, optimization and recommendations for bioretention columns were provided.

Assessment of the thermal properties for the geothermal use of a permeable pavement structure for pedestrian and cycle paths

Sustainable Drainage Systems (SuDS) have positioned themselves as one of the most widely applied Green Infrastructure (GI) techniques for sustainable stormwater management. In recent decades, new lines of research have emerged leading to the geothermal use of SuDS. The aim is to optimise available space in cities and minimise dependence on non-renewable energy sources. Previous research has focused on determining the feasibility of combining the two technologies, both in laboratory and field studies. Other aspects such as the influence of the surface geothermal system on the quality of the water present in the SuDS were also studied. This previous research has focused mainly on permeable pavements, positioning them as one of the SuDS techniques of reference in this line of research. This article attempts to give continuity to what has been established by other authors. It studies in depth the thermal properties of a complete section of permeable pavement under different hydraulic operating conditions. To this end, a complete section of a permeable pavement has been simulated in the laboratory using Hot-Box tests as set out in different international standards. With these tests, the values of thermal transmittance and equivalent thermal conductivity were determined. The aim of this research is to establish a test procedure for the thermal properties of permeable floorings, based on standardised equipment. The aim is to better understand the heat transfer procedures inside SuDS. In this way, it will be possible to optimise the design of these in combination with surface geothermal elements.

Navigating flash floods in Kathmandu Valley: Strategies and policy reforms

Flash floods in Kathmandu Valley are a major concern due to urbanization and drainage issues. Effective change requires policy reforms at the national and local levels, offering incentives and clear frameworks for sustainable stormwater management.

Urban Planning and Sustainable Storm Water Management: Gaps and Potential for Integration for Climate Adaptation Strategies

While climate change urges cities to define appropriate strategies for climate adaptation, urban planning practices are still unable to encompass a broader understanding of hydraulic hazards and to exploit the mitigation potential of nature-based solutions (NBS) for stormwater management. This inability is particularly deep in the Italian context, where the integration of climate adaptation strategies within urban planning is very limited; thus, one of the planner’s overriding needs is to determine where NBS can be most effective. The objective of this paper is to identify key drivers and tools for the introduction of hydrological resilience assessments and sustainable storm water management in urban planning practices, as a contribution to climate adaptation strategies. Through a case study in the city of Bari, the paper proposes a method for identifying the most suitable urban areas for implementing NBS, i.e., areas where NBS are able to intercept runoff. On the other hand, the same approach allows one to evaluate in advance the impact of urban planning choices, or rather of the planned land use change. Finally, the planning tools that may favor the adoption of a NBS approach in urban planning are analyzed, with particular reference to the territorial landscape plan of the Apulia region and urban regeneration plans.

Sustainable Stormwater Management at Urban Expansion Areas of Potential Significant Flood Risk

The Preliminary Flood Risk Assessment (PFRA) for the Greek territory, according to European Directive 2007/60/EC, was completed in 2012 and was revised in 2019. Areas of Potential Significant Flood Risk (APSFR) were defined (and revised) for each River Basin District (RBD). Meanwhile, in 2018, the Flood Risk Management Plans (FRMPs) were approved - by Greek Authorities - for each RBD. In the FRMPs specific measures are proposed for the funding of Stormwater Management (SM) projects that will be designed according to the principles of Sustainable Development (SD), i.e., Best Management Practices (BMPs), Green Infrastructure (GI), Low Impact Development (LID), Urban Natural Water Retention Measures (NWRM) and Sustainable Drainage Systems (SuDS). Within this framework, a preliminary study is drawn up in order to specify some innovative proposals for Sustainable Stormwater Management (SSM) in three areas located into the APSFR of RBD ‘EL11’ (Eastern Macedonia), located in Northern Greece. Two of these areas, Perigiali and Nea Peramos are coastal, while the third one, Doxato, is a continental, plain area. Urban expansion plans are approved for all three cases. The study proposes the implementation of an Innovative Stormwater Management Plan (ISMP) for each area.

Multi-stage planning of LID-GREI urban drainage systems in response to land-use changes

Long-term planning of urban drainage systems aimed at maintaining the sustainability of urban hydrology remains challenging. In this study, an innovative multi-stage planning framework involving two adaptation pathways for optimizing hybrid low impact development and grey infrastructure (LID-GREI) layouts in opposing chronological orders was explored. The Forward Planning and Backward Planning are adaptation pathways to increase LID in chronological order based on the initial development stage of an urban built-up area and reduce LID in reverse chronological order based on the final development stage, respectively. Two resilience indicators, which considered potential risk scenarios of extreme storms and pipeline failures, were used to evaluate the performance of optimized layouts when land-use changed and evolved over time. Compared these two pathways, Forward Planning made the optimized layouts more economical and resilient in most risk scenarios when land-use changed, while the layouts optimized by Backward Planning showed higher resilience only in the initial stage. Furthermore, a decentralized scheme in Forward Planning was chosen as the optimal solution when taking costs, reliability, resilience, and land-use changes into an overall consideration. Nevertheless, this kind of reverse optimization order offers a novel exploration in planning pathways for discovering the alternative optimization schemes. More comprehensive solutions can be provided to decision-makers. The findings will shed a light on the exploration of optimized layouts in terms of spatial configuration and resilience performance in response to land-use changes. This framework can be used to support long-term investment and planning in urban drainage systems for sustainable stormwater management.