Search Results (149)

Land requirements and impacts from future development are a significant concern throughout the world. In Florida (USA), the state’s population increased from 18.8 M to 21.5 M between 2010 and 2020, and is projected to reach 26.6 M by 2040. To accommodate these new residents, 801 km² of wetlands were converted to developed uses between 1996 and 2016. These conversions present a significant threat to Florida’s unique ecosystems and highlight the need to prioritize conservation and water resource protection, both for the natural and human services that wetland and upland landscapes provide. To better understand the relationship between future development and water resources, we used future development and event mean concentration (EMC) models for Escambia and Santa Rosa counties in Florida (USA) to assess impacts from development patterns on water quality/runoff and water resource protection priorities. This study found that if future development densities increased by 30%, reductions of 7713 acres for developed land, 17,768 acre feet of stormwater volume, ~88k lb/yr total nitrogen, and ~15k lb/yr total phosphorus could be achieved. It also found that urban infill, redevelopment, and stormwater management are essential and complementary tools to broader growth management strategies for reducing sprawl while also addressing urban stormwater impacts. Full article

This study explores the reuse of high-resolution 3D spatial datasets for multiple urban analyses within a game engine environment, aligning with circular economy principles in sustainable urban planning. The work is situated in two residential test areas in Finland, where watershed analysis, lighting simulation, and change detection were conducted using data acquired through drone photogrammetry and terrestrial laser scanning. These datasets were processed and visualized using Unreal Engine 5.5, enabling the interactive, multitemporal exploration of urban phenomena. The results demonstrate how a single photogrammetric dataset—originally captured for visual or structural purposes—can serve a broad range of analytical functions, such as simulating seasonal lighting conditions, modeling stormwater runoff, and visualizing spatial changes over time. The study highlights the importance of capturing data at a resolution that satisfies the most demanding intended use, while allowing simpler analyses to benefit simultaneously. Reflections on game engine capabilities, data quality thresholds, and user interactivity underline the feasibility of integrating such tools into citizen participation, housing company decision making, and urban governance. The findings advocate for a circular data approach in urban planning, reducing redundant fieldwork and supporting sustainable data practices through multi-purpose digital twins and spatial simulations. Full article

Lake Winona, a 129 ha eutrophic urban lake comprised of two interconnected basins, exceeds state water quality standards for total phosphorus. Historical lake nutrient data and traditional watershed modeling for the lake’s two basins highlighted multiple major pathways (e.g., municipal stormwater discharges, watershed runoff, internal loading, and wetland discharges) for total phosphorus (P) loading, with >900 kg P/year estimated entering the water columns of each basin. Updated data sources and newer watershed modeling resulted in significantly different (both higher and lower) P loading estimates for the various P sources, especially watershed runoff and internal loading. Overall, basin-specific loading estimates using the updated model were significantly lower (28–40%) than previous estimates: 680 and 546 kg P/year mobilized in the western and eastern basins, respectively. To achieve state water quality standards (<60 ppm P for the western basin, <40 ppm for the eastern basin), watershed and internal P loading each would need to be reduced by approximately 120 kg P/year across the two basins. Reductions could be achieved by a combination of alum treatments to reduce internal loading, removal of common carp (Cyprinus carpio) to prevent interference with alum treatments and nutrient releases via excretion and defecation, and six engineered structures to intercept P before it enters the lake. The different P reduction projects would cost USD 119 to 7920/kg P removed, totaling USD 5.2 million, or USD 40,310/hectare of lake surface area. Full article

Natural wetlands are critical water quality regulators, especially in developing tropical countries. The Lubigi wetland is a large urban wetland in Kampala, the largest city in Uganda in Africa. We studied whether stormwater discharge and wastewater effluent from a nearby stormwater channel and a sewage treatment plant in the western part of the city were cleaned as they flowed through the wetland. Despite the significant pollution, the wetland removed ammonium-nitrogen, orthophosphate, and particulate nutrients during both seasons, achieving removal rates ranging from 50 to 60% for orthophosphate but only 20–40% for ammonium-nitrogen. Overall, seasonal differences in loads and retention rates of nutrient and organic matter inputs were minimal. Interestingly, the wetland mostly released nitrate and nitrite during water passage through the wetland, most likely due to the mineralization of organic nitrogen and agricultural run-off during rainy events in the wet season. However, the limited capacity of the sewage treatment plant and untreated stormwater discharge from the Nsooba main channel reduced the wetland’s ability to clean water. The insufficient carrying capacity of the treatment plant and the release of untreated sewage into the wetland significantly impact the self-purification capacity of the Lubigi wetland. Thus, the concept of Nature-Based Solutions is ineffective if the wetland systems are overloaded. Full article

Green roofs (GRs) are increasingly implemented for stormwater management, and retrofitting conventional roofs is emerging as a key strategy for climate change resilience. However, their impact on diffuse pollution, particularly regarding total organic carbon (TOC) and pollutant mass transport, remains insufficiently understood, especially in aged substrates. This study evaluated and compared the runoff quality from aged GRs and ceramic roofs (CRs) by analyzing TOC, pH, electrical conductivity (EC), first-flush occurrence and intensity, and pollutant release patterns. Results showed that GR retrofitting could help mitigate acid-rain effects due to its elevated pH. Despite higher TOC and EC concentrations in runoff, GRs remained within acceptable water quality limits and exhibited a more gradual release of organic matter over time compared with CRs. Statistical analysis revealed that pollutant concentrations in CR runoff followed Lognormal and Weibull distributions, while GR runoff was best described by Normal, Lognormal, and Weibull distributions. These findings reinforce GRs as a viable stormwater management strategy but highlight the need for full runoff treatment when used for rainwater harvesting. The results also emphasize the importance of tailored statistical models to enhance runoff predictions and optimize GR performance in urban water management. The results provide valuable insights for urban planners and policymakers by reinforcing the potential of GRs in stormwater quality management and supporting the development of incentives for green infrastructure. Future research should expand to different GR configurations, climates, and maintenance practices to enhance the understanding of long-term hydrological and water quality performance. Full article

Extreme precipitation events are one of the common hazards in eastern Texas, generating a large amount of storm water. Water running off urban areas may carry non-point source (NPS) pollution to natural resources such as rivers and lakes. Urbanization exacerbates this issue by increasing impervious surfaces that prevent natural infiltration. This study evaluated the efficacy of rain gardens, a nature-based best management practice (BMP), in mitigating NPS pollution from urban stormwater runoff. Stormwater samples were collected at inflow and outflow points of three rain gardens and analyzed for various water quality parameters, including pH, electrical conductivity, fluoride, chloride, nitrate, nitrite, phosphate, sulfate, salts, carbonates, bicarbonates, sodium, potassium, aluminum, boron, calcium, mercury, arsenic, copper iron lead magnesium, manganese and zinc. Removal efficiencies for nitrate, phosphate, and zinc exceeded 70%, while heavy metals such as lead achieved reductions up to 80%. However, certain parameters, such as calcium, magnesium and conductivity, showed increased outflow concentrations, attributed to substrate leaching. These increases resulted in a higher outflow pH. Overall, the pollutants were removed with an efficiency exceeding 50%. These findings demonstrate that rain gardens are an effective and sustainable solution for managing urban stormwater runoff and mitigating NPS pollution in eastern Texas, particularly in regions vulnerable to extreme precipitation events. Full article

This article examines the application of nature-based solutions in stormwater management in the context of the Global South, focusing on a co-created green infrastructure plan and a pilot intervention project in the city of Paranoá-DF, Brazil. Urban challenges such as extreme floods, droughts, landslides, heatwaves, and biodiversity loss call for innovative planning strategies to enhance adaptation and resilience. The research methodology combined technical analyses, field work, community participation, and stormwater runoff modelling to develop integrated and culturally sensitive solutions to the city’s environmental and socio-economic challenges. This article then presents the outcomes of the community-based participatory workshops, which informed the definition of a green and blue infrastructure network incorporating a range of NBS. Community-identified priorities were used to design urban landscape interventions aimed at enhancing water-related ecosystem services and improving quality of life. Additionally, and supported by hydrological modelling, this article details a localised landscape intervention project that provides new perspectives on urban resilience in this context. Acknowledging the unique challenges faced by cities in the Global South—where social inequities and infrastructure deficits intersect with environmental vulnerabilities—this study highlights the importance of adapting NBS to the contexts of precarious urbanisation patterns. With hydrological stress expected to intensify under climate change, the proposed solutions address the heightened risks faced by low- and middle-income households, promoting more equitable and sustainable urban transformations. Full article

Stormwater runoff containing road deicing salts has led to the increasing salinization of surface waters in northern climates, and urban municipalities are increasingly being mandated to manage stormwater runoff to improve water quality. We assessed chloride concentrations in runoff from late-winter snowmelt and rainfall events flowing into an urban Minnesota, USA, lake during two different years, predicting that specific stormwater drainages with greater concentrations of roadways and parking lots would produce higher chloride loads during runoff than other drainages with fewer impervious surfaces. Chloride levels were measured in runoff draining into Lake Winona via 11 stormwater outfalls, a single channelized creek inlet, and two in-lake locations during each snowmelt or rainfall event from mid-February through early April in 2021 and 2023. In total, 33% of outfall runoff samples entering the lake collected over two years had chloride concentrations exceeding the 230 ppm chronic standard for aquatic life in USA surface waters, but no sample exceeded the 860 ppm acute standard. Chloride concentrations in outfall runoff (mean ± SD; 190 ± 191 ppm, n = 143) were significantly higher than in-lake concentrations (43 ± 14 ppm, n = 25), but chloride levels did not differ significantly between snowmelt and rainfall runoff events. Runoff from highway locations had higher chloride concentrations than runoff from residential areas. Site-specific chloride levels were highly variable both within and between years, with only a single monitored outfall displaying high chloride levels in both years. There are several possible avenues available within the city to reduce deicer use, capture and treat salt-laden runoff, and prevent or reduce the delivery of chlorides to the lake. Full article

Rapid population growth and urbanization are transforming natural landscapes into built environments, resulting in increased stormwater runoff, which poses significant challenges for local governments to manage. Water-Sensitive Urban Design (WSUD) techniques have been implemented to enhance urban stormwater quality, but their effectiveness in managing stormwater quantity and quality across different scales remains uncertain. This study examines the capacity of various WSUD approaches to reduce stormwater runoff volume and peak flow rates in a residential allotment transitioning from a single dwelling to a redeveloped condition with two dwellings. The tested techniques included a rainwater tank, infiltration trench, rain garden, vegetated swale, and permeable pavement. For storm events with a 1-in-5-year Annual Recurrence Interval (ARI)—aligning with typical piped drainage design standards—peak flow rates were reduced by 90% in the redeveloped scenario. Smaller storm events, up to a 1-in-1-year ARI, were frequently eliminated, thereby minimizing disturbances to waterways caused by frequent runoff discharges. Among the tested techniques, the combination of a rainwater tank, rain garden, and infiltration trench demonstrated the greatest effectiveness in reducing stormwater runoff volume and peak flow rates despite considerations of life cycle costs. These findings highlight the potential of integrated WSUD techniques in addressing urban stormwater management challenges. Full article

Green stormwater infrastructure (GSI) is advocated for its potential to provide multiple ecosystem services, including stormwater runoff mitigation, wildlife habitat, and aesthetic value. However, the provision of these ecosystem services depends on both facility design and maintenance, which may vary based on whether GSI was installed to fulfill regulatory construction permit requirements or implemented voluntarily as part of urban greening initiatives. We evaluated 76 GSI facilities distributed across Baltimore, MD, USA, comprising 48 voluntary and 28 regulatory facilities. Each facility was scored on indicators related to the provision of stormwater, habitat, and aesthetic ecosystem services. Ecosystem service scores were highly variable, reflecting a wide range of quality and condition, but we found no significant differences between scores for regulatory and voluntary GSI. However, voluntary GSI scores tended to be higher in areas with greater socioeconomic status, while regulatory facilities showed an inverse relationship. Our findings indicate that GSI facilities can degrade quickly, and that official maintenance requirements for regulatory facilities do not guarantee upkeep. Regulatory requirements did have better outcomes in areas with lower socioeconomic status, though. Degraded GSI facilities may do more harm than good, becoming both unsightly and ineffective at providing intended stormwater or habitat benefits. Full article

Anthropization has significantly altered the natural water cycle by increasing impermeable surfaces, reducing evapotranspiration, and limiting groundwater recharge. Permeable Interlocking Concrete Pavements (PICPs) have emerged as a permeable pavement, effectively reducing runoff and improving water quality. This study investigates the base depth for PICPs regarding the strength and permeability. This study examines the hydraulic and structural performance of Permeable Interlocking Concrete Pavements (PICPs) for urban and industrial applications by evaluating the effects of subgrade conditions, traffic loads, and material properties. Using DesignPave and PermPave software, the optimal base layer thickness is determined to prevent rutting while ensuring effective stormwater infiltration beneath 110 mm-thick concrete pavers placed on a 30 mm-thick bedding course. The required base thickness for urban pavements ranges from 100 mm to 395 mm, whereas for industrial pavements, it varies between 580 mm and 1760 mm, depending on subgrade permeability, traffic volume, and loading conditions. The findings demonstrate that PICPs serve as a viable and environmentally sustainable alternative to conventional impermeable pavements, offering significant hydrological and ecological benefits. Full article

Transport areas in urban environments typically cover 10–20% of a city’s area. Due to their hierarchical structure and network layout, they present a unique opportunity to integrate Nature-based Solutions (NbSs) within cities strategically. In Poland, however, the current use of NbSs in streetscapes tends to be sporadic, localized, and often resulting from grassroots initiatives. This study aimed to assess how much the provision of ecosystem services (ESs) in cities depends on and can be enhanced by NbSs. To explore this, simulations were conducted using six NbSs scenarios, selected based on an analysis of solutions specifically designed for streets and their characteristics. This research focused on a densely built and populated district of Warsaw. The findings revealed that applying NbSs can significantly reduce stormwater runoff, increase carbon sequestration, and improve air quality. The level of ES provision depends on the solutions used, with the introduction of woody vegetation, particularly tall shrubs and trees, proving most effective. The results show that the scenario-based approach allows for flexible streetscape design, enabling the application of individually selected NbSs. Moreover, the approach helps to select optimal elements that enhance the provision of ES crucial to adapting cities to climate change. Full article

Urbanization and the expansion of impervious surfaces have increased stormwater runoff volumes, altered runoff timing, and degraded water quality and aquatic ecosystems. Runoff from urban areas carries pollutants such as nitrogen, phosphorus, sediments, and heavy metals, which can adversely impact the physical characteristics of receiving waterbodies. Stormwater management programs aim to mitigate these effects using Best Management Practices (BMPs) to retain and treat stormwater on-site. However, in densely developed areas, space constraints and high costs often make traditional BMPs impractical. This study assessed the effectiveness of expanded shale, an engineered material, as a filtration medium in bioswales, a type of linear BMP commonly used in transportation infrastructure. Thirty scenarios were tested in a 16 ft (4.9 m) long plexiglass flume using expanded shale mixed with sandy clay soil. Due to the limited scope of this study, it focused on assessing the effectiveness of expanded shale in removing suspended sediments and reducing turbidity. Results showed that expanded shale achieved removal efficiencies ranging from 20% to 82% for total suspended solids (TSS) and −4% to 61% for turbidity under different conditions. It outperformed conventional filtration materials such as sand and gravel, requiring less channel length. Remarkably, even in a small-scale laboratory setting, expanded shale met the suspended sediment removal standard of 80%, demonstrating its potential as a highly effective filtration material alternative for urban stormwater management. Full article

In an urban region of eastern Tijuana, there are long-standing water runoff sites which community members have identified as having an impact on residents, including contributing to flooding. This community-based participatory research (CBPR) project in collaboration with the Colectivo Salud y Justicia Ambiental (CSJA) used the geospatial surveying tool Survey 123 to conduct community-based monitoring of five runoff sites. Results from 170 completed surveys showed that water runoff was present at these sites on forty-five percent of the days surveyed, although there was no significant relationship between the temporal factors studied and the water quality characteristics surveyed. These findings contribute to the field of border environmental justice by focusing on the understudied issues of runoff and urban flooding as environmental exposures that some communities experience disproportionately. Moreover, while there was a significant relationship between water runoff volume and precipitation events at the water runoff sites, there were sixty-five surveys collected that showed water present when there had been no precipitation event at the site. This finding supports the CSJA members’ assertions that the runoff experienced in the study area is not always connected to precipitation events or pluvial flooding. This project’s results contribute to policy advocacy by countering the policy narrative that this issue is simply a stormwater issue, and by identifying the specific runoff sites to be prioritized in this region. Full article

This study addresses the persistent issue of urban waterlogging in Wujin District, Changzhou City, Jiangsu Province, using a comprehensive approach integrating an optimized drainage network and low-impact development (LID) measures. Utilizing the Storm Water Management Model (SWMM), calibrated with extensive hydrological and hydraulic data, the model was refined through genetic algorithm-based optimization to enhance drainage efficiency. Key results indicate a substantial reduction in the average duration of waterlogging from 7.43 h to 3.12 h and a decrease in average floodwater depth from 21.27 cm to 8.65 cm. Improvements in the drainage network layout, such as the construction of new stormwater mains, branch drains, and rainwater storage facilities, combined with LID interventions like permeable pavements and rain gardens, have led to a 56.82% increase in drainage efficiency and a 63.88% reduction in system failure rates. The implementation effectively minimized peak flood flow by 25.38%, reduced runoff, and improved groundwater recharge and rainwater utilization. The proposed solutions offer a replicable, sustainable framework for mitigating flooding in urban environments, enhancing ecological resilience, and ensuring the safety and quality of urban life in densely populated areas. Full article