Search Results (22)

Extreme rainfall in urban areas can cause major economic damage, a problem expected to intensify with climate change. Despite this, high-resolution studies at the city scale remain limited. This study analyzes rainfall organization and storm dynamics over Barcelona using data from a dense rain gauge network (1994–2019). The aim is to identify dominant spatial patterns and understand how storms evolve in relation to local urban and topographic features. Principal component analysis and simple scaling analysis revealed signs of a rainfall island effect, possibly linked to the urban heat island and modulated by orographic and coastal influences. Tailored rainfall indices highlighted a division between inland areas shaped by orography and coastal zones influenced by the sea. These spatial structures evolved with rainfall duration, shifting from localized contrasts at a 10 min resolution to more homogeneous distributions at daily scales. Storm tracking showed that 90% of speeds ranged from 5 to 60 km/h and intense rainfall events typically moved east–southeast toward the sea and north–northeast. Faster storms tended to follow preferred directions reflecting mesoscale circulations and possible modulations by local terrain. These findings underscore how urban morphology, local relief, and a coastal setting may shape rainfall at the city scale, in interaction with broader Mediterranean synoptic dynamics. Full article

Rapid urbanization in Karachi, Pakistan, has resulted in increased impervious surfaces, leading to significant challenges, such as frequent flooding, urban heat islands, and loss of vegetation. These issues pose challenges to urban resilience, livability, and sustainability, which further demand solutions that incorporate urban greening and effective water management. This research uses remote sensing technologies and Geographic Information Systems (GISs), to analyze current surface treatments and their relationship to Karachi’s blue-green infrastructure. By following this approach, we evaluate flood risk and identify key flood-conditioning factors, including elevation, slope, rainfall distribution, drainage density, and land use/land cover changes. By utilizing the Analytical Hierarchy Process (AHP), we develop a flood risk assessment framework and a comprehensive flood risk map. Additionally, this research proposes an innovative Sponge City (SC) framework that integrates nature-based solutions (NBS) into urban planning, especially advocating for the establishment of green infrastructure, such as green roofs, rain gardens, and vegetated parks, to enhance water retention and drainage capacity. The findings highlight the urgent need for targeted policies and stakeholder engagement strategies to implement sustainable urban greening practices that address flooding and enhance the livability of Karachi. This work not only advances the theoretical understanding of Sponge Cities but also provides practical insights for policymakers, urban planners, and local communities facing similar sustainability challenges. Full article

The frequent occurrence of urban floods (UFs) poses significant threats to public safety and the national economy. Accurate estimation of urban flood susceptibility (UFS) and the identification of potential hotspots are critical for effective UF management. However, existing UFS studies often fall short due to a limited understanding of UFs’ nature, frequently relying on disaster factors analogous to those used for natural floods while neglecting key urban characteristics, limiting the accuracy of UFS estimates. To address these challenges, we propose a novel framework for UFS assessment. Unlike those studies that focus primarily on topographic and surface characteristics, our approach integrates urban-specific factors that capture the distinctive attributes of the urban environment, including Urban Heat Island Intensity, Urban Rain Island Intensity, Urban Resilience Index, and Impervious Surface Percentage. Guangzhou was selected as the study area, where machine learning methods were employed to calculate UFS, and Shapley Additive Explanation was utilized to quantify the contributions of employed factors. We evaluated the significance of urban factors from three perspectives: classifier performance, map accuracy, and factor importance. The results indicate that (1) urban factors hold significantly greater importance compared to other factors, and (2) the incorporation of urban factors markedly enhances both the performance of the trained classifier and the accuracy of the UFS map. These findings underscore the value of integrating urban factors into UFS assessments, thereby contributing to more precise UF management and supporting sustainable urban development. Full article

Urban public space faces increasing challenges due to the accelerating impacts of climate change, necessitating a paradigm shift in how cities adapt their built environments. This paper presents a case study on integrating Nature-based Solutions(NbSs) with urban infrastructure, focusing on the design and development of Urban Oasis, a modular and multi-sensory urban furniture system. Urban Oasis functions as a climate adaptation tool, incorporating rain gardens to manage stormwater, mitigate urban heat island effects, and enhance biodiversity while integrating smart features such as climate sensors, irrigation systems, lighting, speakers, and electric vehicle chargers. Through a practice-based design methodology, the study explores how transdisciplinary collaboration can inform the development of adaptive, resilient, and equitable urban interventions. The findings demonstrate the potential of NbS-integrated urban infrastructure to address the complexities of climate adaptation while enhancing social, ecological, and technological resilience. The results, validated through an integrated design checklist, contribute to ongoing discussions on urban design frameworks, emphasizing a multi-layered and systemic approach that intertwines architecture, social innovation, multi-species design, and sensory engagement to reimagine public space for future climate resilience. Full article

On 19 September 2021, a strombolian volcanic eruption began on the island of La Palma in the Canary Islands. This event resulted in the destruction of 73 km of roads, urban infrastructure, numerous houses, and agricultural crops, affecting approximately 7200 people and causing losses exceeding 1.2 billion euros. Around 12 km² were covered by aa and pahoehoe lava flows, which reached thicknesses of over 70 m. Following the end of the eruption, thermal, geological, and geotechnical site investigations were carried out for the reconstruction and territorial and urban planning, with the main objectives focused on opening roads through hot lava, constructing new urban settlements in areas covered by lava flows, and facilitating the agricultural recovery. The primary challenges to reconstruction included the very slow cooling rate of the lava, resulting in persistent high temperatures, exceeding 500 °C, its highly heterogeneous geotechnical properties with numerous cavities and lava caves, and the presence of toxic gases. Site investigations included geotechnical boreholes, seismic geophysics and ground-penetration radar, and temperature measurements of lava flows using drones and thermocouple devices inside boreholes. To estimate the cooling rates of the lava flows, two physical cooling models were developed based on thermal behavior and geological–geotechnical data. The results indicated that lava cooling durations in some areas exceed practical waiting times for commencing reconstruction. This led to the development of geological engineering solutions that permit road construction and urban and agricultural reconstruction to begin sooner than estimated by the cooling models. On the other hand, potential hazards arising from the eruption process have also been taken into account. Stability analyses of the 200 m high volcanic cone formed during the eruption indicate the possibility of failure in the event of heavy rain and consequently lahar hazards. The results of the investigations carried out and their applications to post-disaster reconstruction may be useful for other volcanic regions, contributing to minimizing risk to infrastructure and urban settlements. Full article

In recent years, the frequency and intensity of global extreme weather events have gradually increased, leading to significant changes in urban rainfall patterns. The uneven distribution of rainfall has caused varying degrees of water security issues in different regions. Accurately grasping the spatiotemporal distribution patterns of rainfall is crucial for understanding the hydrological cycle and predicting the availability of water resources. This study collected rainfall data every five minutes from 62 rain gauge stations in the main urban area of Kunming City from 2019 to 2021, constructing an unsupervised hybrid dimensionality reduction-clustering (HDRC) model. The model employs the Locally Linear Embedding (LLE) algorithm from manifold learning for dimensionality reduction of the data samples and uses the dynamic clustering K-Means algorithm for cluster analysis. The results show that the model categorizes the rainfall in the Kunming area into three types: The first type has its rainfall center distributed on the north shore of Dian Lake and the southern part of Kunming’s main urban area, with spatial dynamics showing the rainfall distribution gradually developing from the Dian Lake water body towards the land. The second type’s rainfall center is located in the northern mountainous area of Kunming, with a smaller spatial dynamic change trend. The water vapor has a relatively fixed and concentrated rainfall center due to the orographic uplift effect of the mountains. The third type’s rainfall center is located in the main urban area of Kunming, with this type of rainfall showing smaller variations in all indicators, mainly occurring in May and September when the temperature is lower, related to the urban heat island effect. This research provides a general workflow for spatial rainfall classification, capable of mining the spatiotemporal distribution patterns of regional rainfall based on extensive data and generating typical samples of rainfall types. Full article

As the global temperature and rapid urbanization continue to rise, urban heat islands (UHIs) also continue to increase across the world. Following the heat equity concept, UHIs disproportionately impact disadvantaged or overburdened communities. Green infrastructure (GI) has been at the forefront of UHI mitigation efforts, including nature-based solutions like parks, pervious open spaces, wooded areas, green roofs, rain gardens, and shade trees. In this paper, we use a heat equity lens to analyze community perceptions of the intersection of climate change, UHI, and GI in Camden, New Jersey—a post-industrial city with a history of environmental injustices. Based on a mixed-methods analysis of survey responses (n = 107), 11 years of relevant X (formerly Twitter) posts (n = 367), and geospatial data, we present community perceptions of and connections between climate change, UHI, and GI and discuss major themes that emerged from the data: perceived heat inequity in Camden triggers negative emotions; a public knowledge gap exists regarding climate change-UHI-GI connections; and perceived inequitable distribution of GI and certain GI planning and maintenance practices may negatively impact UHI mitigation strategies. We argue these themes are useful to urban planners and relevant professionals while planning for heat equity and mitigating UHI effects in disadvantaged urban communities like Camden. Full article

Vertical greenery not only helps to cool the surfaces of buildings but, more importantly, it can also mitigate the Urban Heat Island effect. The growth of vertical greenery is highly dependent on ongoing maintenance, such as irrigation. Wind-driven rain serves as a natural source of irrigation for vertical greenery. Wind-driven rain simulation was conducted on a typical high-density and high-rise case in Hong Kong to first classify the wind-driven rain harvesting potential on the façade with very high, high, moderate, low, and very low levels. Then, Scenario 1 (very high potential), Scenario 2 (very high + high potential), and Scenario 3 (very high + high + moderate potential) regarding vertical greenery in locations with three levels of wind-driven rain harvesting potential were simulated in ENVI-met to assess its Urban Heat Island mitigation effect. The maximum temperature reduction on the street occurs between 12 p.m. and 3 p.m., indicating the greatest mitigation of the Urban Heat Island effect. Scenario 1, Scenario 2, and Scenario 3 achieve a maximum temperature reduction of 0.76 °C, 0.88 °C, and 1.06 °C, respectively, during this time period. Full article

This paper responds to the research question, “can urban farming in Nepal help create sustainable cities?” Especially after the COVID-19 pandemic, urban residents have begun to realize that food transported from long distances is not always reliable. Urban farming can help produce fresh food locally and help urban residents become self-reliant by engaging in healthy eating habits and practicing sustainable agricultural techniques in food-desert areas, while creating a positive impact on the environment through regenerative agricultural methods. In doing so, urban farms can help the growers save on food expenditures and even earn some additional income, while also improving air quality and minimizing the effects of urban heat islands. This practice also helps reduce greenhouse gases through plant carbon use efficiency (CUE), as vegetation carbon dynamics (VCD) can be adjusted while supporting the circular economy. As urban lands command higher prices than agricultural land, urban farming usually happens on residential yards, roofs, balconies, community gardens, and dedicated areas in public parks. Rainwater harvesting and redirecting can help irrigate urban farms, which can be part of rain gardens. The national census of 2021 identified that 66% of Nepal’s population lives in urban areas. However, the World Bank (2018) showed that only 21 of Nepal’s population was projected to live in urban areas in 2021. It is not debatable that the urbanization process in Nepal is on the rise. Thus, urban agriculture can play an important role in supplementing residents’ food needs. Many cities in Nepal have already successfully adapted to urban farming wherein residents grow food on their building sites, balconies, and rooftop, often growing plants in pots, vases, and other types of containers. The UN-Habitat, with the support of the European Union and local agencies, published a rooftop farming training manual (2014), showing the feasibility of urban farming in Nepal. This paper discusses how public-private partnership (PPP) can promote urban agriculture and make the process more effective and attractive to urban-farming households. It also analyzes how a PPP approach also facilitates the use of better technology, advisory support, and use of research extension activities. This paper draws on a literature review, uses remote-sensing imagery data and data from National Census Nepal 2021, and the authors’ professional experiences related to best practices in the areas to analyze the benefits and challenges related to urban farming both in Nepal and Arizona, USA. The paper provides recommendations for Nepali cities to maximize the benefit provided by urban farming. It is expected to be useful to Nepali policymakers, government agencies, and nonprofit organizations which promote sustainability, and organic farming with a sustainable supply chain. Full article

Operation of source control measures (SCM) in urban drainage in tropical/transitional climates are still a challenge because of higher rain volumes and more intense rains, as well as constraints from sea-level interference. In this study, the performance of a swale to control runoff was detailed and monitored in such an environment. The data on rain, runoff, and sea levels were acquired at a site located in an island in the south coast of Brazil. The results showed that even with higher rain volumes and more intense rains, the mean capture of the swale was 51.7% of the entrance runoff volume, but it depended on seasonal rain variation and interference of sea/tide level. As a result, the swale might be undersized in summer and oversized in winter. Peak flow retardation was observed in 97% of monitored events. The interference of sea/tide level was not directly correlated with infiltration volumes, but in the principal component analysis, the parameters of sea/tide level, along with the hydrological parameters of rain duration, height, and intensity, explained 60% of the variance in the data. In conclusion, the application of SCMs in tropical regions is suitable, but seasonality should be incorporated in the design. The interference of sea/tide level must be further investigated to verify how to incorporate its influence in the design. Full article

Urban areas with dark and impermeable surfaces are known to have a heating effect on air and still water compared to surrounding areas, called the urban heat island effect (UHI). UHI and stormwater discharges’ collective impact on stream temperature, especially regarding seasonal changes, is a less-studied field. In this study, the temperature effect of the urban village Aarslev on Stream Vindinge in Southern Denmark was examined. Loggers (ID A–L) were placed in Stream Vindinge in 2020–2021, measuring temperature (°C) and pressure (kPa). Outlets were analyzed with respect to origin: Direct stormwater outlets (rain ÷ basin), stormwater delayed by ponds (rain + basin), common overflow, and common sewage from WWTP. Data showed the stream temperature rise through Aarslev village in all months (except March) with 0.3–1.9 °C, most notably in the summer months. A one-way ANOVA confirmed that the upstream station A and downstream station K were significantly different (p-values < 0.001). No significant difference in temperatures between the different outlet types was found. An increase in stream temperature was observed in response to rain events, followed by a temperature decrease. This was assumed to be a “first heat flush”. This was speculated to mean less optimal conditions for trout and sensitive macroinvertebrates not because of heat shock, but rather to lower O₂ concentrations and higher mineralization. River and lake temperatures are projected to increase, and this effect might become more pronounced. A decrease in stream temperature was observed after the village (station L). Therefore, it was concluded that the rise in temperature through the village was due to UHI. Full article

Precipitation is a critical factor affecting regional water cycles, water ecology, and socioeconomic development. Monthly precipitation, water vapor pressure, and temperature datasets from 613 meteorological stations across China were used to analyze the spatiotemporal evolution of urban rain island effects at the national scale during periods of slow (1960–1969) and accelerated (2010–2019) urbanization. The combined effects of artificial water dissipation and heat islands on urban precipitation were a key focus of this study. The results showed that rain island effects (0–31.6 mm/month) were primarily distributed along the southeast coast (dominated by the heat island effect) and northwest inland region (dominated by artificial water dissipation). During winter, the relative contribution of artificial water dissipation was higher in urban areas, and the rain island effect was more apparent than in the summer. Comparisons of precipitation prior to and following large-scale urbanization showed that precipitation and rain island intensity along the southeast coast and northwest inland region increased by 0–28 and 0–28.6 mm/month, respectively. These findings indicate that artificial water dissipation is an important water vapor source for urban precipitation, particularly during winter months. Full article

Increasing awareness of global and local climate change and the limited resources of land, surface, water, raw materials, urban green spaces, and biodiversity alter the exigencies of urban development. Already perceivable local climate changes such as heavy rains, droughts, and urban heat islands urge planners to take action. Particularly in densely populated areas, conflicting interests are pre-programmed, and decision making has to include multiple impacts, mutual competition, and interaction with respect to investments into provisioning services. Urban planners and municipal enterprises increasingly work with digital tools for urban planning and management to improve the processes of identifying social or urbanistic problems and redevelopment strategies. For this, they use 2D/3D city models, land survey registers, land use and re-/development plans or other official data. Moreover, they increasingly request data-based planning tools to identify and face said challenges and to assess potential interventions holistically. Thus, this contribution provides a review of 51 current tools. Simple informational tools, such as visualizations or GIS viewers, are widely available. However, databases and tools for explicit and data-based urban resource management are sparse. Only a few focus on integrated assessment, decision, and planning support with respect to impact and cost assessments, real-time dashboards, forecasts, scenario analyses, and comparisons of alternative options. Full article

With the acceleration of urbanization, climate problems affecting human health and safe operation of cities have intensified, such as heat island effect, haze, and acid rain. Using high-resolution remote sensing mapping image data to design scientific and efficient algorithms to excavate and plan urban ventilation corridors and improve urban ventilation environment is an effective way to solve these problems. In this paper, we use unmanned aerial vehicle (UAV) tilt photography technology to obtain high-precision remote sensing image digital elevation model (DEM) and digital surface model (DSM) data, count the city’s dominant wind direction in each season using long-term meteorological data, and use building height to calculate the dominant wind direction. The projection algorithm calculates the windward area density of this dominant direction. Under the guidance of K-means, the binarized windward area density map is used to determine each area and boundary of potential ventilation corridors within the threshold range, and the length and angle of each area’s fitted elliptical long axis are calculated to extract the ventilation corridors that meet the criteria. On the basis of high-precision stereo remote sensing data from UAV, the paper uses image classification, segmentation, fitting, and fusion algorithms to intelligently mine potential urban ventilation corridors, and the effectiveness of the proposed method is demonstrated through a case study in Zhuji City, Zhejiang Province. Full article

The concept of biophilic urban planning has inspired neighborhood greening projects in many older urban communities in the USA and beyond. The strengths (e.g., environmental management, biodiversity, heat island mitigation) and challenges (e.g., greenwashing, green gentrification) of such projects are well-documented. Additional research on the relationship between these projects and various social factors (e.g., public perceptions, feelings, and mental health and well-being) is necessary to better understand how people adapt to said projects while struggling to navigate other more pressing socioeconomic issues, especially in communities facing environmental injustice and health inequity. In this article, we focus on one aspect of biophilic urban planning—green stormwater infrastructure (GSI) (e.g., rain gardens, bio-swales, pervious pavements, and wildflower meadows)—in Waterfront South, a post-industrial neighborhood in Camden, NJ, USA, where residents have faced environmental injustices for decades. Our qualitative analysis of in-depth semi-structured interviews of sixteen residents offered a thorough insight into their perceptions and emotions regarding different types of urban GSI projects. Residents acknowledge the many benefits that GSI offers to combat the neighborhood’s social and environmental injustices, but they are cautious about the possibility of some projects prompting new issues and concerns within the community. Our findings reveal potential implications in GSI planning, research, and practice in this neighborhood and similar urban places elsewhere that have yet to undergo gentrification. Full article