Search Results (217)

Low-impact development (LID) and nonpoint-source pollution reduction facilities are increasingly expected to function as long-term components of urban infrastructure rather than as isolated environmental features. Their sustainability depends not only on technical design but also on institutional review, construction assurance, operation and maintenance, performance verification, information continuity, and adaptive policy learning. This study comparatively examines the content and structure of three major South Korean guidance documents issued in 2013, 2016, and 2020: the national LID Technology-Element Guideline, Seoul’s Guidance for the LID Prior-Consultation System, and the national Manual for the Installation and Management/Operation of Nonpoint-Source Pollution Reduction Facilities. A directed qualitative content analysis was conducted using seven literature-informed lifecycle-governance dimensions covering problem framing, planning and approval, facility selection and sizing, installation and construction control, operation and maintenance, monitoring and performance verification, and adaptive feedback. Documentary provisions were assessed using a four-level ordinal scale ranging from absent to strong coverage. The analysis indicates a functional expansion of governance provisions across the three documents, from LID principles and technology selection to pre-permit review, quantitative runoff-management requirements, installation guidance, operation and maintenance, monitoring, and performance testing. However, the documents collectively show discontinuities between approval and construction verification, construction and long-term operation, maintenance and compliance, monitoring and policy learning, and lifecycle information management. In response, this study proposes a six-stage lifecycle-governance framework linking planning, pre-permit verification, construction commissioning, asset registration, risk-based maintenance and monitoring, and adaptive policy learning. The framework is presented as an analytical and normative synthesis rather than an empirically validated governance model. Because the study is limited to documentary analysis, the findings do not demonstrate actual implementation effectiveness, regulatory compliance, maintenance quality, or environmental performance and should be validated through future empirical and comparative research. Full article

Urban stormwater poses a threat to urban safety and development. The systematic spatial planning of low-impact development (LID) facilities is increasingly recognized as a sustainable approach to enhancing urban flood resilience. Previous studies have largely focused on empirically-based design approaches or have employed uncoupled computational methods, resulting in a lack of accuracy in flood simulation results. In this study, a novel framework was proposed. The Non-dominated Sorting Genetic Algorithm II was employed to perform multi-objective optimization of the spatial layout of LID facilities, and a coupled model of SWMM and TELEMAC was developed to simulate surface flooding based on the optimized schemes. Under three rainfall scenarios, three schemes on the Pareto Front—representing the lowest cost, the optimal compromise and the least overflow—were selected to investigate how scheme parameters and overflow are influenced by rainfall intensity and design preferences. The results indicate that scheme parameters and node overflow show greater variation under the influence of different design preferences than under different rainfall conditions. Taking the schemes selected in this study as examples, under the lowest-cost scheme, LID coverage was less than 10%, resulting in a limited reduction in node overflow; but when ‘minimum overflow’ was set as the design preference, node overflow was virtually eliminated, with peak water levels at flood-prone locations reduced to 0.05 m, 0.08 m and 0.10 m under 50-year, 100-year and 200-year storm conditions, respectively. The framework for urban flooding simulation and flood control scheme design proposed in this study is potentially applicable to comparable settings, subject to similar data availability and physical conditions, serving as a reference for enhancing urban resilience to flooding. Full article

Given the scarcity of initiatives to charge for urban stormwater services in Brazil and the need to recognise users’ efforts in adopting technologies such as Low Impact Development (LID), a proposal was developed for a stormwater drainage fee and incentives for environmental services in a Brazilian municipality, based on flows retained by LIDs, specifically infiltration wells. To this end, simulations were carried out using the Storm Water Management Model (SWMM) for a 0.5 km² area in a Brazilian city that does not yet implement such charges. Based on the identification of the total flow retained by users within the watershed, the avoided cost to the drainage system was estimated. The charging model was defined using the avoided cost method associated with the Simplified Equivalent Residential Unit (SERU). In the baseline scenario that allocates the operation and maintenance cost, the estimated annual fee was USD 17.22 per household without LID and USD 14.64 per household with LID, and the SERU area was 371.11 m², used as a property-area reference; in an incentive scenario designed to reduce the user payback period to approximately 10 years, the fee for households without LID was set at USD 73.78. An economic incentive policy was identified, consisting of fee discounts upon adoption of LIDs, as well as support for their installation and maintenance. Thus, it was validated that combining a drainage fee with economic incentives is both feasible and motivating for both system users and managers. Full article

Indian metropolitan cities such as Mumbai grapple with rapid urbanisation, extreme urban density, high built-up areas, loss of green cover, and shrinking open spaces, resulting in increased impermeable surfaces, urban heat island effects, and frequent flooding occurrences. Modern stormwater management has increasingly been characterised by integrated grey-green approaches; however, cities in the Global North benefit from established policies, technical expertise, and financial resources that enable the systematic and large-scale integration of Blue-Green Infrastructure (BGI) through district-wide geospatial assessment frameworks, unlike many cities in the Global South. Despite growing interest in nature-based stormwater solutions, there remains a dearth of geospatial empirical research from India examining the placement, distribution, performance, and functionality of BGI integrated with existing stormwater management systems in cities such as Mumbai. Furthermore, hydrological modelling using tools such as the Storm Water Management Model (SWMM) for the design, planning, and implementation of BGI in Indian cities remains largely unexplored. This study explores the role of BGI strategies in improving urban stormwater management within high-density Indian cities under a 25-year return period extreme rainfall scenario. Using an integrated approach that combines QGIS-based spatial analysis with EPA-SWMM hydrologic-hydraulic modelling, the research examines runoff behaviour, identifies flooding hotspots, and evaluates the effectiveness of Low Impact Development (LID)-based BGI measures such as permeable pavements, infiltration trenches, and green roofs applied at the ward level in Mumbai’s F/North and G/North Wards. Detailed land use classification, spatial mapping, and rainfall simulation corresponding specifically to a 25-year return period rainfall event was used to assess pre- and post-intervention conditions. The findings indicate that the applied BGI measures led to a 12.6% reduction in peak runoff (137.6 m³/s to 120.2 m³/s) and a 5.5% decrease in total runoff volume (783,510 m³ to 740,410 m³). More importantly, the peak flooding flow rate decreased by 45% (94.1 m³/s to 51.7 m³/s), demonstrating that BGI measures can efficiently reduce peak flooding flows by extending runoff hydrographs during extreme rainfall events. These findings are specifically applicable to the simulated 25-year return period extreme rainfall scenario and may vary under different rainfall intensities or return periods. Less extreme events could potentially experience even greater relative reductions or prevent flooding altogether, while also easing downstream hydraulic loads. Overall, strategically placed BGI interventions can significantly reduce surface runoff and peak flow, thereby enhancing stormwater resilience within spatially constrained urban environments. This study provides a replicable, data-driven framework for catchment-scale stormwater planning in dense Indian cities under extreme rainfall conditions, offering practical insights into methods, local contextual considerations, and spatial planning strategies for policymakers and urban planners seeking to retrofit and adapt existing infrastructure under increasing hydrologic stress and climate variability. Full article

Low-impact development (LID) facilities can significantly mitigate runoff and purify pollutants. However, their operational efficiency is highly influenced by regional rainfall characteristics, posing challenges to sustainable development in urban water management. This study investigates the degradation of runoff control efficacy in two LID installations located in Xi’an (semi-humid region) and Yangzhou (humid region) and examines the impact of continuous rainfall across different climatic zones. The results reveal that in both study areas, over 75% of annual rainy days experienced continuous rainfall, accounting for more than 80% of total rainfall volume. During continuous rainfall, the declining infiltration capacity of LID facilities reduces their performance, and the operational effectiveness of the LID facilities may deviate to some extent from the design goals. The lower attenuation coefficients observed in Yangzhou indicate that its LID facilities were more strongly affected by continuous rainfall than those in Xi’an. Regarding the designed annual runoff control targets, Xi’an achieved an average effectiveness of 83.7% at 60–85% design levels, outperforming Yangzhou by 12.09%. When increasing design rainfall, Xi’an exhibited increments of 41.0–200.7% for targets ranging from 60% to 80%, whereas Yangzhou required substantially larger increases for targets of 60–70%. Notably, achieving control targets above 85% in Xi’an and 75% in Yangzhou solely through increased design rainfall proved unfeasible. The study highlights that continuous rainfall affects LID performance in both humid and semi-humid regions, with facilities in more humid climates being particularly susceptible. These findings underscore the need for climate-adaptive LID design strategies to support long-term sustainable urban development goals. Full article

Urban pluvial flooding is becoming more severe in rapidly urbanizing cities under increasingly frequent extreme rainfall. Although Low Impact Development (LID) is widely used to improve infiltration and on-site stormwater retention, its hydrological performance may differ greatly across urban functional zones with distinct land-cover patterns, development intensity, and retrofit constraints. To address the lack of comparative evidence under consistent conditions, this study mapped land cover in five representative functional zones in Nanjing—old residential, new residential, commercial, industrial, and cultural/educational areas—and applied a unified CITYgreen (SCS-CN) framework under a 72 mm, 24 h, two-year design storm to simulate four standalone LID measures: ground-level greening, permeable pavement, green roofs, and grassed swales. Results showed big zone-dependent differences in hydrological benefits. Runoff reduction was greatest in highly impervious industrial and commercial areas, whereas the new residential zone showed only a marginal improvement due to its relatively favorable baseline retention conditions. Across all zones, measures that enhanced infiltration and near-surface storage performed best, with ground-level greening and permeable pavement achieving the highest retention efficiency. These findings highlight the importance of zoning-based, context-sensitive LID prioritization for urban renewal, sponge-city retrofitting, and stormwater planning in rapidly urbanizing cities. Full article

Effective microclimate regulation and rainwater management have become critical challenges in residential environments. Bioretention (BR) facilities are widely applied low-impact development (LID) measures that provide co-benefits in runoff control and microclimate regulation. However, the effects of BR designs and runoff control targets on microclimate performance remain unclear. Using ENVI-met simulations, this study evaluated the microclimate regulation performance of simple and engineered BR configurations under varying total annual runoff control rates (RCRs) across 28 scenarios in a community in Nanjing, China, considering sunny and post-rainfall conditions. Results showed the following: (1) Simple and engineered BR facilities exhibit distinct microclimate regulation pathways: simple BR shows a stable improvement in microclimate regulation with increasing facility area, whereas engineered BR shows declining effectiveness when RCR exceeds 75%. (2) Rainfall enhances the cooling and humidifying effects of both BR alternatives, enhancing microclimate regulation on post-rainfall conditions. (3) BR selection should be aligned with RCR targets. When RCR ≤ 75%, no substantial difference is observed between the two BR alternatives, while simple BR demonstrates better cooling effectiveness and higher implementation efficiency at higher RCRs. This study provides practical guidance for optimizing bioretention design to balance runoff control and microclimate regulation in residential-scale LID planning. Full article

Historic cities face a dual challenge of managing waterlogging risks while adhering to strict preservation constraints. Traditional drainage upgrades often require extensive excavation, threatening cultural heritage. This study establishes a quantitative assessment framework for the historic urban district of City B using a 1D-2D-coupled hydrodynamic model (InfoWorks ICM). The model was calibrated using continuous monitoring data, achieving a Nash–Sutcliffe Efficiency (NSE) of 0.91. Its spatial accuracy was subsequently validated against historical waterlogging records, showing a strong consistency between simulated flood-prone areas and observed flood locations. We simulated waterlogging distribution under rainfall events with return periods of 0.5 to 5 years. Results reveal two key deficiencies in the current drainage system under a 0.5-year return period storm event. Firstly, 75.3% of the pipe segments are hydraulically overloaded, failing to meet the design standard. Secondly, this widespread network overload contributes to surface waterlogging, with 9.58 ha (1.80% of the total area) being waterlogged. We evaluated three strategies: Low Impact Development (LID), underground storage tanks, and intercepting sewers. A hybrid grey-green infrastructure (HGGI) system was proposed, integrating source reduction and terminal storage. The HGGI system reduced waterlogged areas by 83.58% (0.5-year event) and 64.87% (5-year event), outperforming single measures. Crucially, this hybrid system achieves minimal intervention in historic street patterns through trenchless construction for intercepting sewers, decentralized LID layout and underground storage tanks, avoiding large-scale road excavation while enhancing flood resilience. This study demonstrates that hybrid strategies can effectively balance flood resilience with environmental and cultural preservation in high-density historic districts. Full article

Conventional centralized drainage systems exacerbate urban flooding, pollution, and water stress. Low-impact development (LID) is a decentralized alternative; however, its multifunctional benefits, which go beyond the control of stormwater, are often undervalued in planning. This study fills this gap by developing an integrated benefit valuation framework to systematically quantify and estimate the economic value of the co-benefits of five widely implemented LID facilities (vegetated swale, green roof, in-filtration ditch, infiltration trench, and permeable pavement) in Seoul, South Korea. The framework combines annual benefits in four key sectors: water management (runoff reduction), energy savings (building cooling/heating demands), air quality (pollutant deposition and avoided emissions) and climate change (carbon sequestration and mitigation). Applying a transparent, localized spreadsheet model, the results indicate significant multifunctional value for LID systems. While water management provides the primary benefit, there is substantial added value in energy, air quality, and climate co-benefits. In the case of green roofs, such ancillary benefits can exceed hydrological values. The analysis further reveals a consistent scale-benefit relationship and a clear trade-off between the magnitude of benefits and the cost of implementation. This provides evidence of the need for context-sensitive, portfolio-based LID planning. The proposed framework is a practical decision support tool for urban planners and policymakers to consider LID not only as a stormwater solution but also as multifunctional green infrastructure that simultaneously promotes urban water security, energy efficiency, environmental quality, and climate resilience. Full article

Old urban areas are often prone to waterlogging and sewage contamination owing to their haphazard spatial arrangements, extensive impervious surfaces, and insufficient drainage infrastructure, thereby posing significant risks to both public safety and aquatic ecosystems. Sponge City retrofitting offers a viable solution. Currently, the study area is facing issues of waterlogging and pollution caused by rainfall. Conventional modeling approaches for optimizing the spatial allocation of Low-Impact Development (LID) practices typically quantify only the overall retrofit proportion. However, these methods fail to specify the optimal placement of individual facilities to balance hydrological benefits against construction costs. To bridge this gap between theoretical optimization and practical implementation, this study proposes an iterative approximation framework. First, the Non-Dominated Sorting Genetic Algorithm II (NSGA-II) was coupled with the Storm Water Management Model (SWMM) to generate a Pareto front, from which optimal solutions were selected using the Analytic Hierarchy Process (AHP). The configuration was further refined through multiple iterations of “exhaustive search combined with Euclidean distance” analysis to determine the optimal types and locations of LID facilities. The results show that: In Scenario 3, the Euclidean distance after LID retrofitting achieved a narrowing gap from 5 to 3 to 1. This indicates that the proposed progressive approximation solving process can be directly applied to specific retrofit targets, providing concrete construction guidance for LID retrofitting in older communities’ areas. Conclusions showed that (1) the specific locations for implementing LID facilities within sub-catchments become progressively clearer, ultimately defining precise retrofitting sites. (2) The proposed progressive approximation approach effectively and systematically reduces this disparity. (3) Retrofitted LID measures effectively managed stormwater and controlled pollution. Full article

Climate change and rapid urbanization are increasingly disrupting urban water cycles by intensifying runoff and reducing infiltration, particularly in watersheds designated for future development. However, most existing studies have focused on fully urbanized areas, with limited attention given to semi-rural or urban–rural transition watersheds at the planning stage. In this context, the Dawoon watershed in Ulsan, Republic of Korea, represents a critical case, as it is currently undeveloped but designated for large-scale urban expansion. This study evaluates the effectiveness of Low Impact Development (LID) strategies in restoring water-cycle soundness under anticipated urbanization conditions. A hydrological model of the Dawoon watershed was developed using the Storm Water Management Model (SWMM), and multiple land-use-specific LID scenarios were designed to reflect realistic planning-stage applications. Long-term simulations were conducted to assess changes in runoff, infiltration, evapotranspiration, and overall water-cycle performance. The results indicate that urban development substantially increases surface runoff while reducing infiltration and evapotranspiration. The integrated application of LID measures significantly mitigated these impacts, reducing total runoff by approximately 3% and improving the water cycle recovery rate to nearly 99%, restoring hydrological conditions close to the pre-development state. Among the evaluated scenarios, the combined implementation of vegetated swales, infiltration–storage basins, green roofs, and permeable pavements showed the highest effectiveness. These findings highlight the importance of incorporating LID strategies at the early stages of urban planning to enhance climate resilience and prevent long-term water cycle degradation. The proposed framework provides practical guidance for setting water-cycle management targets and selecting effective LID measures in developing or peri-urban watersheds. Full article

Global warming is modifying precipitation patterns, and hence increasing the hazards of severe and extended rainstorms. Addressing the gap in integrating economic and environmental assessments into urban stormwater management—a key challenge in urban water resource analysis—this study utilizes the analytical hierarchy process (AHP) and SUSTAIN model to identify and evaluate low-impact development (LID) stormwater management strategies, assessing their impacts on runoff volume, peak flow reduction, chemical oxygen demand (COD), and suspended solids (SS) across four planning scenarios under five rainfall recurrence intervals, culminating in a cost–benefit analysis to ascertain the optimal scenario. The reduction rates for COD and SS varied from 41.85% to 87.11% across different scenarios, with Scenario Three (RM03) demonstrating the highest efficacy in pollutant management. (The four labels RM01–RM04 are used throughout the text to represent the four scenarios) Implementing the best plan may result in a reduction of yearly carbon emissions of 189.70 metric tons, with emissions from the operational load of the drainage network and COD pollution treatment potentially decreasing by 2.44% and 2.06%, respectively, indicating an overall annual reduction of 85.46%. This approach not only mitigates urban rainwater and flooding issues but also prevents resource wastage, optimizes resource utilization and benefits, offers a scientific foundation for urban construction and planning, and serves as a reference for sponge city development in other regions. Full article

In arid regions, rainfall is scarce, summer-concentrated, and prone to extreme events, while evaporation exceeds precipitation, creating fragile ecosystems that need scientific stormwater management for flood resilience. Sponge cities, through the implementation of green infrastructure, can alleviate urban flooding, improve rainwater utilization, and enhance the urban ecological environment. Under the “dual carbon” target, sponge city construction has gained new developmental significance. It must not only ensure core functions and minimize construction costs but also fully leverage its carbon reduction potential, thereby serving as a crucial pathway for promoting urban green and low-carbon development. Therefore, this study focused on Xining, a typical arid city in Northwest China, and couples the Non-dominated Sorting Genetic Algorithm-III (NSGA-III) with the Storm Water Management Model (SWMM) to construct a multi-objective optimization model for Low Impact Development (LID) facilities. The layout optimization design of LID facilities is conducted from three dimensions: life cycle cost (LCC), rainwater utilization rate (K), and carbon emission intensity (CI). Hydrological simulations and scheme optimizations were performed under different design rainfall events. Subsequently, the entropy-weighted TOPSIS method was utilized to evaluate and compare these optimized schemes. It is shown by the results that: (1) The optimized LID schemes achieved a K of 76.2–80.43%, an LCC of 2.413–3.019 billion yuan, and a CI of −2.8 to 0.19 kg/m²; (2) Compared with the no-LID scenario, the optimized scheme significantly enhanced hydrological regulation, flood mitigation, and pollutant removal. Under different rainfall return periods, the annual runoff control rate increased from 64.97% to 80.66–82.23%, with total runoff reduction rates reaching 46.41–49.26% and peak flow reductions of 45–47.62%. Under the rainfall event with a 10-year return period, the total number of waterlogging nodes decreased from 108 to 82, and the number of nodes with a ponding duration exceeding 1 h was reduced by 62.5%. The removal efficiency of total suspended solids (TSS) under the optimized scheme remained stable above 60%. The optimized scheme is highly adaptable to the rainwater management needs of arid areas by prioritizing “infiltration and retention”. Vegetative swales emerge as the primary facility due to their low cost and high carbon sink capacity. This study provides a feasible pathway and decision-making support for the low-carbon layout of LID facilities in arid regions. Full article

The development of urban areas and the proliferation of impervious surfaces have significantly altered natural hydrological cycles, resulting in an increase in stormwater runoff and substantial risks to groundwater quality. This review synthesizes current research on the transport mechanisms of stormwater contaminants, including toxic elements, nutrients, pathogens, and emerging pollutants such as microplastics and pharmaceuticals, into aquifers. This study analyzes the physicochemical and biological processes that affect pollutant mobility and retention in urban soils, emphasizing the vulnerability of groundwater systems, particularly in areas with permeable soils and shallow water tables. The article evaluates a range of green infrastructure (GI) and low-impact development (LID) strategies—including rain gardens, bioswales, infiltration basins, constructed wetlands, and urban forestry—to assess how effectively they can mitigate stormwater pollution and improve groundwater protection. Case studies from North America illustrate the practical implementation and performance of GI systems, emphasizing the importance of site-specific design, monitoring, and adaptive management. The review also discusses global policy frameworks and community engagement strategies that support sustainable stormwater management. Ultimately, it advocates for an integrated, multidisciplinary approach that combines engineering, ecological science, and public policy to safeguard groundwater resources in the face of climate variability and urban expansion. Full article

Outcomes for urban green infrastructure (GI) and low-impact development (LID) vary; thus, we ask when and how public participation affects performance. We apply a four-dimensional framework—breadth (who participates), depth (decision influence), identity (values/place attachment), and potential (incentives/capacity)—to conduct a literature review of Web of Science, Scopus, and Google Scholar. After deduplication and screening, 107 English-language studies were coded and compared across cases. Across contexts, early and representative engagement combined with clearly specified decision rights was associated with designs better aligned with local hydrologic and social conditions. Processes that attend to identity were consistently linked to stewardship behaviors. Institutionalized incentives and capacity, such as dedicated funding, defined roles, and feedback mechanisms, coincided with more durable operations and maintenance (O&M). Conversely, broad outreach without decision influence or feedback tended to remain tokenistic, with technical complexity and resource limits attenuating public influence. Effects appeared configurational rather than linear, with particular combinations of the four dimensions more often associated with success. Embedding codesign and feedback across the project lifecycle, pairing equity safeguards with community partnerships, and resourcing participation through clearly defined roles and incentives may help translate participation into resilient ecological and social outcomes. Full article