The effects of flooding on mental health: Outcomes and recommendations from a review of the literature

Impact of "blue-green diet" on human health and wellbeing: A systematic review of potential determinants in shaping the effectiveness of blue-green infrastructure (BGI) in urban settings

Discourses concerning the potential health benefits of blue-green infrastructure (BGI) have gained momentum, highlighting its positive influence on human health and wellbeing. While studies have explored the concept of "Nature Pyramid" and the role of exposure to natural environments in promoting health, the role of water elements remains underexplored. Rooted in this concept, this study proposed a notion of "blue-green diet" as a framework to understand the intricate mechanisms and determinants of optimal blue-green exposure. Understanding the relationship between these determinants and their health-related impacts can facilitate the enhancement of BGI design, leading to greater effectiveness in promoting health and wellbeing and supporting sustainable urban development strategies. To enhance the comprehension of the "blue-green diet", this study conducted a systematic literature review to grasp the underlying mechanisms behind its beneficial effects, focusing on two key determinants of "blue-green diet", which are also derived from the concept of the "Nature Pyramid": (1) the type of BGI and (2) the mode of interaction with and within BGIs. Under the search of BGI's overall health impacts, this study selected 54 journal publications concerning BGI's type and interaction mode from Web of Science and Scopus since 2010. The review revealed significant disparities in the health benefits provided by different types of BGI (in terms of artificial extent and scale) and between active and passive interaction modes. It examines how to balance natural and artificial elements for enhancing the benefits of BGI and discusses the attributes of BGI that encourage diverse and meaningful interaction patterns. These efforts collectively aim to optimize BGI design and planning, increase its capacity to promote health, and extend its benefits to a wider range of individuals. Future research should encompass a broader spectrum of determinants, such as diverse BGI settings, visit frequency and duration, and user's social-cultural backgrounds.

Geospatial analytics of driving mechanism of land subsidence in Gulf Coast of Texas, United States

Land subsidence has been an ongoing issue for over a century along the Gulf Coast of Texas in the United States. This study assesses and models the factors contributing to land subsidence covering fifty-six (56) counties along the Gulf of Mexico coastline from Louisiana to the border of Mexico, approximately 300,000 km2. Geospatial statistical techniques and regression models were employed to investigate and predict the fundamental causes of land subsidence by integrating multiple datasets such as Global Navigation Satellite System (GNSS) (147 stations), groundwater extraction (78,420 wells), hydrocarbon production (84,424 wells), precipitation, and population growth. In the last two decades, the overall population rose by 33 % and the compound annual population growth rate increased from 2.08 to 4.10 % in Montgomery, Waller, Fort Bend, and Chambers counties. Emerging hotspot analysis reveals that the groundwater level is persistently declining and the regression model (R2 = 0.92) tested over Harris County predicts that the population growth significantly contributes to land subsidence in this region. The groundwater withdrawal rate is increased from 23 to 96.6 billion gallons in Harris, Montgomery, and Fort Bend counties in the last two decades. A prolonged drought from 2010 to 2015 due to low precipitation affected all fifty-six counties. Oil production increased eightfold and a high extraction rate of 19.5 to 40.1 million bbl/yr of oil in Karnes County was recorded within the last 20 years. The regression model (R2 = 0.73) over this county suggests that oil extraction is a primary contributing factor to the observed subsidence. Although the gas extraction rates for all counties are decreasing over time, some counties in the southern part of the Gulf Coast Aquifer show relatively higher extraction rates. For the first time, this research determines that all fifty-six counties along the Gulf Coast of Texas are undergoing land subsidence and experiencing high population growth, groundwater withdrawal, and hydrocarbon extraction.

Opportunities and challenges in green stormwater infrastructure (GSI): A comprehensive and bibliometric review of ecosystem services from 2000 to 2021

The great challenges induced by global climate change coupled with rapid urbanization underline the growing urgency for a change in stormwater management with a novel integrated approach. This study conducted a comprehensive review on state-of-the-art knowledge in the research field of green storm infrastructure (GSI) using bibliometric analysis. A corpus of 3988 GSI-related publications (2000-2021) extracted from the Web of Science database was used to evaluate the scientific output in GSI research through the "Bibliometrix" R package and "CiteSpace". Ever since 2010, the number of publications per year exhibited an exponential increase, with the annual publication growth rate of 28.61%. Notably, the United States (23.55%) and China (19.58%) contributed most in GSI publications. "Water" (306) was identified as the most relevant journal in GIS research field, followed by "Sustainability" (252) and "Science of the Total Environment" (200). Cluster analysis unveiled the predominant research themes, i.e., "Conceptual development of GSI" (69.25%), "Adaptation of GSI" (46.89%), and "Performance evaluation of GSI practices" (18.28%). Research foci have generally shifted from conventional engineering-based frameworks (e.g., reduce stormwater runoff and enhance water quality) to ecological-based multi-elements (e.g., preserve natural resources, augment urban biodiversity and optimize land-use patterns). This systematic review concludes trends, challenges and future research prospects of GSI, and aims to provide reference and guidance for decision-makers on the development of a more dynamic, resilient, and robust integrated GSI approach for sustainable urban stormwater management.

Climate change impacts on wastewater infrastructure: A systematic review and typological adaptation strategy

Wastewater infrastructures play an indispensable role in society's functioning, human production activities, and sanitation safety. However, climate change has posed a serious threat to wastewater infrastructures. To date, a comprehensive summary with rigorous evidence evaluation for the impact of climate change on wastewater infrastructure is lacking. We conducted a systematic review for scientific literature, grey literature, and news. In total, 61,649 documents were retrieved, and 96 of them were deemed relevant and subjected to detailed analysis. We developed a typological adaptation strategy for city-level decision-making for cities in all-income contexts to cope with climate change for wastewater structures. 84% and 60% of present studies focused on the higher-income countries and sewer systems, respectively. Overflow, breakage, and corrosion were the primary challenge for sewer systems, while inundation and fluctuation of treatment performance were the major issues for wastewater treatment plants. In order to adapt to the climate change impact, typological adaptation strategy was developed to provide a simple guideline to rapidly select the adaptation measures for vulnerable wastewater facilities for cities with various income levels. Future studies are encouraged to focus more on the model-related improvement/prediction, the impact of climate change on other wastewater facilities besides sewers, and countries with low or lower-middle incomes. This review provided insight to comprehensively understand the climate change impact on wastewater facilities and facilitate the policymaking in coping with climate change.

Can flood resilience of green-grey-blue system cope with future uncertainty?

Urban flooding is becoming a great global concern due to growing cities, while climate change and urbanization may pose daunting challenges to both environment and humans. The integrated green-grey-blue (IGGB) system has gained interests worldwide to mitigate flood issues, however, how IGGB system acts in urban flood resilience and whether it can address future uncertainties have not been fully understood. In this study, a new framework, which combined an evaluation index system and coupling model, was constructed to quantify urban flood resilience (FR) and its responses to future uncertainties. The results showed that higher FR upstream than downstream; however, upstream FR declined approximately twice as much as downstream when faced with climate change and urbanization. Generally, climate change appeared to have a greater impact on urban flood resilience than urbanization, resulting to 3.20%-4.28% and 2.08%-4.09% FR reduction, respectively. The IGGB system could greatly improve robustness against future uncertainty, due to the fact that the IGGB without low impact development facilities (LIDs) was about 2 times in FR decline compared with IGGB with LIDs. The increase of LIDs proportion could diminish the impact of climate change, which shifted the dominant factor affecting FR from the interaction between urbanization and climate change to urbanization. Notably, a threshold of 13% construction land increase was quantified, beyond which negative effects of rainfall become dominant again. The results could guide IGGB design and urban flooding management in other similar regions.

Incorporating Microbial Species Interaction in Management of Freshwater Toxic Cyanobacteria: A Systems Science Challenge

Water resources are critically important, but also pose risks of exposure to toxic and pathogenic microbes. Increasingly, a concern is toxic cyanobacteria, which have been linked to the death and disease of humans, domesticated animals, and wildlife in freshwater systems worldwide. Management approaches successful at reducing cyanobacterial abundance and toxin production have tended to be short-term solutions applied on small scales (e.g., algaecide application) or solutions that entail difficult multifaceted investments (e.g., modification of landscape and land use to reduce nutrient inputs). However, implementation of these approaches can be undermined by microbial species interactions that (a) provide toxic cyanobacteria with protection against the method of control or (b) permit toxic cyanobacteria to be replaced by other significant microbial threats. Understanding these interactions is necessary to avoid such scenarios and can provide a framework for novel strategies to enhance freshwater resource management via systems science (e.g., pairing existing physical and chemical approaches against cyanobacteria with ecological strategies such as manipulation of natural enemies, targeting of facilitators, and reduction of benthic occupancy and recruitment). Here, we review pertinent examples of the interactions and highlight potential applications of what is known.

Understanding positive contributions to sustainability. A systematic review

Current approaches for measuring and assessing contributions of companies and their products to sustainability largely focus on reducing negative impacts. However, becoming "less bad" still means having adverse impacts on the environment. Various authors have therefore called for investigating how positive contributions can be made to further sustainable development. This systematic literature review explores how positive contributions to sustainability have been discussed in the environmental management literature dealing with sustainability performance measurement and assessment. Our review of 328 publications reveals an understanding of positive contributions to sustainability that is a mostly implicit or vague use. Inductive analysis, however, reveals three distinct understandings - an operationalization, a stakeholder and a transformation perspective - each of which is embedded in a different theoretical frame, namely decision, stakeholder and transition theory. These perspectives have so far been discussed separately in the literature. By drawing on theoretical foundations of performance measurement, we propose an integrated understanding of positive contributions to sustainability: A positive sustainability contribution has the goal of bringing about a sustainability transformation, considers the environmental, economic and social context through stakeholder participation, and is operationalized to facilitate decision-making and the implementation of effective sustainability measures. A clear definition is of key importance for both research and practice to both reduce negative and increase positive contributions to sustainable development.

Fuzzy Comprehensive Evaluation Model of the Farmers’ Sense of Gain in the Provision of Rural Infrastructures: The Case of Tourism-Oriented Rural Areas of China

During the rapid development of rural infrastructures in China, many important issues such as the real wishes of farmers and the proper management of the infrastructure have been overlooked, resulting in a weak sense of gain among farmers. To propose effective improvement strategies, this research aimed to explore the influence mechanism of the farmers’ sense of gain and to build a comprehensive evaluation model of farmers’ sense of gain in the provision of rural infrastructure. To achieve the above aims, we first proposed hypotheses among four constructs and selected an evaluation index for each construct. Using Structural Equation Modeling (SEM) and a questionnaire survey, we then verified the proposed hypotheses and developed a fuzzy comprehensive evaluation model of the farmers’ sense of gain in the provision of rural infrastructure. The results first showed that the content of gain and the way of gain directly affect the farmers’ sense of gain, and the governance indirectly affects the farmers’ sense of gain. Moreover, the way of gain has the greatest impact on the sense of gain, followed by the governance and the content of gain. Furthermore, the analysis results demonstrate that the developed fuzzy comprehensive evaluation model is feasible and effective in evaluating farmers’ sense of gain in the provision of rural infrastructures. The findings of this study first enrich the relevant theories of farmers’ sense of gain in the provision of rural infrastructure. The findings also provide theoretical support for the government authorities to put forward effective governance strategies for rural infrastructure from the perspective of farmers’ sense of gain.

Impacts of Zagreb’s Urban Development on Dynamic Changes in Stream Landscapes from Mid-Twentieth Century

Urban streams constitute a valuable form of multi-functional blue and green infrastructure (BGI) and can support urban development to generate ecosystem, social, and economic benefits. In global cities, planning for BGI enhancement contributes to climate change adaptation, ecosystem restoration, community health and wellbeing, improved quality of life, etc. This research aims to assess the dynamics of stream landscape change in Zagreb as well as the influence of urban development on the blue and green landscape and related urban values. The analysis of landscape features and their planning is conducted at the level of the stream system of the whole city of Zagreb and at the level of two stream sequences by superimposing spatial data from cartographic sources. By developing an urban planning-social-ecological approach to evaluation, monitoring, and management, a quantitative and qualitative trend in stream landscape changes is identified and indicators for detecting areas of critical urbanization pressure are established. This research confirms the trend of negative changes in the urban BGI, evident in the present state (interruption of open streams, and the reduction, fragmentation, and disconnection of blue and green landscape), as well as in the planned neglect (plans for further stream closures and reduction in public green areas). Stream landscape potential is emphasized as one of the greatest urban assets for improving the system of BGI, and areas needed for their prioritization in urban planning measures, directed towards an increase in multiple landscape values, are determined.

Blue-Green Infrastructure for Flood and Water Quality Management in Southeast Asia: Evidence and Knowledge Gaps

In Southeast Asia, projections of rapid urban growth coupled with high water-related risks call for large investments in infrastructure-including in blue-green infrastructure (BGI) such as forests, parks, or vegetated engineered systems. However, most of the knowledge on BGI is produced in the global North, overlooking the diversity of urban contexts globally. Here, we review the literature on BGI for flood risk mitigation and water quality improvement in Southeast Asian cities to understand the scope of practical knowledge and identify research needs. We searched for evidence of local types of BGI in peer-reviewed and grey literature and assessed the performance of BGI based on hydrological, societal, and environmental metrics. The body of literature on BGI in Southeast Asia is small and dominated by wealthier countries but we found evidence of uptake among researchers and practitioners in most countries. Bioretention systems, constructed wetlands, and green cover received the most attention in research. Evidence from modelling and laboratory studies confirmed the potential for BGI to address flooding and water quality issues in the region. However, practical knowledge to mainstream the implementation of BGI remains limited, with insufficient primary hydrological data and information on societal and environmental impacts. In addition, the performance of BGI in combination with grey infrastructure, under climate change, or in informal settlements is poorly studied. Future research and practice should focus on producing and sharing empirical data, ultimately increasing the regional knowledge base to promote efficient BGI strategies.

Understanding Urban Green Space Usage through Systems Thinking: A Case Study in Thamesmead, London

Urban green spaces provide environmental, economic, societal and health benefits to cities. However, policy and planning interventions aiming to improve usage have often led to unintended consequences, including, in some circumstances, an actual decline in usage. Previous research has identified factors influencing the use of urban green space, more often with a focus on the ‘quality’ and physical features of the space, rather than on the broader social factors. This study aims to unpack the complexity of factors that influence the use of urban green space through the application of Systems Thinking. A qualitative mixed-method approach integrating System Dynamics with rapid ethnography was adopted to elicit the views of local residents in Thamesmead, London. A thematic analysis of interviews was undertaken to systematically map the causal relations between factors, which were compared to wider stakeholders’ views. Our findings highlight the relevance of dynamics and social influences on the use of green space, which include social interactions and stewardship, health conditions, availability of services and amenities. These are factors that are underexplored in the literature and, sometimes, overlooked in urban green space policy by decision-makers. We infer that attendance of urban green spaces requires time, which may be occupied in other practices determined by local conditions and needs. Expanding the spatial and temporal boundaries of investigation, wider than debates on ‘quality’, should, in our view, increase the chances of identifying critical influences and foster an increased use of green space.

Stakeholders’ Perceptions on the Role of Urban Green Infrastructure in Providing Ecosystem Services for Human Well-Being

The perception of linkages between ecosystem services (ES) and the urban green infrastructure (UGI) is evaluated, and their impact on human well-being (WB) is defined. Using a theoretical approach, the UGI’s specific contribution to WB is calculated as the sum of the products of (a) the number of perceived ES per ES group and the WB weight factor divided by the product of (b) the number of respondents and (c) the sum of the products of ES and the WB weight factor. Stakeholders demand more ES than the perceived ES supply from all types of UGI, especially for the social relations component of WB. The highest number of perceived ES and greatest impact on all WB components is provided by urban forests. This method could be helpful in acknowledging ES and involving stakeholders not previously familiar with the ES concept with the aim of introducing ES into UGI governance.

Public preferences for green infrastructure improvements in Northern New Jersey: a discrete choice experiment approach

Significant water pollution caused by flooding due to heavy precipitation and extreme weather events has become a considerable problem in urbanized areas such as in Northern New Jersey. These cities experience heavy downpour-related contamination and water pollution when stormwater and untreated sewage are diverted through combined sewer overflow drainage systems to adjacent water bodies. Green infrastructure has proven a successful intervention method for mitigating these unintended environmental consequences. However, while the effects of CSOs and the ability of GI to reduce them are well documented, there has been considerably less study addressing public preferences and willingness to pay for GI-based solutions. As such, this study seeks to understand these facets of GI management in urbanized areas of New Jersey, focusing on Newark, Paterson, and Elizabeth townships. A discrete choice experiment method was used to analyze the willingness of residents to pay for additional CSO infrastructure through the installation of GI options such as bioretention gardens, rain barrels, and green roofs. Furthermore, study identified attributes such as secondary benefits, proximity, and water retention that respondents found the most utility in when choosing GI stormwater management interventions. We found that several attributes, including improved air quality ($58.60), increased water supply ($49.71), and closer proximity ($110.01-$125.97) had the highest utility and similarly were associated with a higher willingness to pay than other tested attributes. These findings are important in assessing the overall attitude toward these fixtures, and may be critical in crafting local policy and development, especially to address environmental equity.

Impact of sewer overflow on public health: A comprehensive scientometric analysis and systematic review

Sewer overflow (SO), which has attracted global attention, poses serious threat to public health and ecosystem. SO impacts public health via consumption of contaminated drinking water, aerosolization of pathogens, food-chain transmission, and direct contact with fecally-polluted rivers and beach sediments during recreation. However, no study has attempted to map the linkage between SO and public health including Covid-19 using scientometric analysis and systematic review of literature. Results showed that only few countries were actively involved in SO research in relation to public health. Furthermore, there are renewed calls to scale up environmental surveillance to safeguard public health. To safeguard public health, it is important for public health authorities to optimize water and wastewater treatment plants and improve building ventilation and plumbing systems to minimize pathogen transmission within buildings and transportation systems. In addition, health authorities should formulate appropriate policies that can enhance environmental surveillance and facilitate real-time monitoring of sewer overflow. Increased public awareness on strict personal hygiene and point-of-use-water-treatment such as boiling drinking water will go a long way to safeguard public health. Ecotoxicological studies and health risk assessment of exposure to pathogens via different transmission routes is also required to appropriately inform the use of lockdowns, minimize their socio-economic impact and guide evidence-based welfare/social policy interventions. Soft infrastructures, optimized sewer maintenance and prescreening of sewer overflow are recommended to reduce stormwater burden on wastewater treatment plant, curtail pathogen transmission and marine plastic pollution. Comprehensive, integrated surveillance and global collaborative efforts are important to curtail on-going Covid-19 pandemic and improve resilience against future pandemics.

Land Subsidence in the Texas Coastal Bend: Locations, Rates, Triggers, and Consequences

Land subsidence and sea level rise are well-known, ongoing problems that are negatively impacting the entire Texas coast. Although ground-based monitoring techniques using long-term global navigation satellite systems (GNSS) records provide accurate subsidence rates, they are labor intensive, expensive, time-consuming, and spatially limited. In this study, interferometric synthetic aperture radar (InSAR) data and techniques were used to map the locations and quantify rates of land subsidence in the Texas Coastal Bend region during the period from October 2016 to July 2019. InSAR-derived land subsidence rates were then validated and calibrated against GNSS-derived rates. The factors controlling the observed land subsidence rates and locations were investigated. The consequences of spatial variability in land subsidence rates in Coastal Bend were also examined. The results indicated that: (1) land subsidence rates in the Texas Coastal Bend exhibited spatial variability, (2) InSAR-derived land subsidence rates were consistent with GNSS-derived deformation rates, (3) land subsidence in the Texas Coastal Bend could be attributed mainly to hydrocarbon and groundwater extraction as well as vertical movements along growth faults, and (4) land subsidence increased both flood frequency and severity in the Texas Coastal Bend. Our results provide valuable information regarding not only land deformation rates in the Texas Coastal Bend region, but also the effectiveness of interferometric techniques for other coastal rural areas around the globe.

Green Infrastructure and Health

The health benefits of green space are well known, but the health effects of green infrastructure less so. Green infrastructure goes well beyond the presence of green space and refers more to a strategically planned network of natural and seminatural areas, with other environmental features designed and managed to deliver a wide range of ecosystem services and possibly to improve human health. In this narrative review, we found that small green infrastructure, such as green roofs and walls, has the potential to mitigate urban flooding, attenuate indoor temperatures and heat islands, improve air quality, and muffle noise, among other benefits, but these effects have not been linked directly to health. Larger green infrastructure has been associated with reduced temperatures, air pollution, and crimes and violence, but less so with health, although some evidence suggests that it may be beneficial for health (e.g., good health, decreased mortality). Finally, parks and street trees show many health benefits, but it is not clear if they can always be considered green infrastructure.

Beliefs about Human-Nature Relationships and Implications for Investment and Stewardship Surrounding Land-Water System Conservation

When engaging stakeholders in environmental conservation, it is critical to understand not only their group-level needs, but also the individually held beliefs that contribute to each person’s decisions to endorse or reject policies. To this end, we examined the extent to which people conceptualize the interconnected relationship between humans and nature in the context of a hypothetical urban waterway, and the implications thereof for environmental investment and stewardship. We also explored how these beliefs varied based on describing the waterway as having either local or global impacts, and as originating either naturally or through artificial processes. Three hundred and seventy-nine adults from the United States read vignettes about a polluted urban waterway and thereafter reported their investment in river clean-up, their stewardship of the river, and their beliefs surrounding human-nature relationships. Results revealed a common belief pattern whereby humans were believed to impact the urban river disproportionately more than the river impacts humans, suggesting that lay adults often weigh the impacts of humans on the natural world disproportionally. Critically, this disproportionate pattern of thinking inversely predicted investment of time and money in river clean-up. Results also revealed a potential solution to this psychological bias: highlighting local benefits of the waterway decreased the asymmetry of the human-nature relationship. We discuss the psychological factors contributing to this cognitive bias, and the implications of these findings on stakeholder engagement.

Urban Wetlands: A Review on Ecological and Cultural Values

Wetlands are a critical part of natural environments that offer a wide range of ecosystem services. In urban areas, wetlands contribute to the livability of cities through improving the water quality, carbon sequestration, providing habitats for wildlife species, reducing the effects of urban heat islands, and creating recreation opportunities. However, maintaining wetlands in urban areas faces many challenges, such as the reduction of hydrological functions, changed water regimes due to barriers, contamination by wastewater, habitat loss due to land-use change, and loss of biodiversity due to the entry of alien species. In this article, we review the theoretical background of wetlands in urban areas through the existing studies in the literature. We provide knowledge on urban wetlands and highlight the benefits of these wetlands in urban areas. These benefits include sustainability, biodiversity, urban heat islands, social perception, and recreation values. We also summarize the objectives, methodologies, and findings of the reviewed articles in five tables. In addition, we summarize the critical research gaps addressed in the reviewed articles. Our review study addresses the research gaps by performing a rigorous analysis to identify significant open research challenges, showing the path toward future research in the field. We further discuss and highlight the role of policymakers and stakeholders in preserving wetlands and finally present our conclusions.

Assessment of Blue and Green Infrastructure Solutions in Shaping Urban Public Spaces—Spatial and Functional, Environmental, and Social Aspects

Blue and Green Infrastructure (BGI) provide one of the key Nature Based Solution (NBS) approaches for sustainable stormwater management in cities, in conjunction with extending the scope of Ecosystem Services (ES). In both the process of planning and designing highly urbanized areas, the implementation of BGI is important for the improvement of living conditions and counteracting the negative effects of climate change. Based on the literature review, 19 BGI solutions were identified and then valorized in relation to the following three key aspects: spatial and functional, environmental, and social. The results of the assessment were derived using the scoring method and allowed for the identification of BGI solutions with a high, medium or low value for shaping sustainable urban public spaces. Using the potential of analyzed BGI solutions to improve the functioning and attractiveness of urban areas requires a comprehensive approach. Conscious planning and designing should use the knowledge presented to make the implementation of BGI solutions as effective as possible in relation to the above-mentioned aspects of shaping urban public spaces.

A multi-scalar perspective on health and urban housing: an umbrella review

With more than half the world's population living in cities, understanding how the built environment impacts human health at different urban scales is crucial. To be able to shape cities for health, an understanding is needed of planetary health impacts, which encompass the human health impacts of human-caused disruptions on the Earth's natural ecosystems. This umbrella review maps health evidence across the spatial scales of the built environment (building; neighbourhood; and wider system, including city, regional and planetary levels), with a specific focus on urban housing. Systematic reviews published in English between January 2011 and December 2020 were searched across 20 databases, with 1176 articles identified and 124 articles screened for inclusion. Findings suggests that most evidence reports on health determinants at the neighbourhood level, such as greenspace, physical and socio-economic conditions, transport infrastructure and access to local services. Physical health outcomes are also primarily reported, with an emerging interest in mental health outcomes. There is little evidence on planetary health outcomes and significant gaps in the research literature are identified. Based on these findings, three potential directions are identified for future research.

The Potential of Stormwater Management in Addressing the Urban Heat Island Effect: An Economic Valuation

Urban green infrastructure (UGI) within sustainable stormwater management provides numerous benefits to urban residents, including urban heat island (UHI) mitigation. Cost–benefit analyses (CBA) for UGI have been conducted at neighborhood level with a focus on stormwater management, but valuations of reductions in heat-related hospitalizations and mortality are lacking. These benefits create significant social value; the quantification thereof is essential for urban planning in providing a scientific foundation for the inclusion of UGI in UHI mitigation strategies. This study assesses the potential of three UGI scenarios developed for an urban neighborhood in Berlin, Germany. First, climate data analyses were conducted to determine the cooling effects of tree drains, facade greening, and green roofs. Second, a CBA was performed for each scenario to value UHI mitigation by estimating the damage costs avoided in reduced heat-related hospitalizations and fatalities, using the net present value (NPV) and benefit–cost ratio (BCR) as indicators of economic feasibility. The results indicate heat mitigation capabilities of all three UGI types, with tree drains achieving the strongest cooling effects. Regarding economic feasibility, all scenarios achieve positive NPVs and BCRs above one. The findings confirm the potential of stormwater management in mitigating UHI and generating substantial social value.

The climate benefits, co-benefits, and trade-offs of green infrastructure: A systematic literature review

Climate change increases risks to natural and human systems. Green infrastructure (GI) has been increasingly recognized as a promising nature-based solution for climate change adaptation, mitigation, and other societal objectives for sustainable development. Although the climate contribution of GI has been extensively addressed in the literature, the linkages between the climate benefits and associated co-benefits and trade-offs remain unclear. We systematically reviewed the evidence from 141 papers, focusing on their climate benefits, relevant co-benefits and trade-offs, and the GI types that provide such climate (co-)benefits. This study presents a comprehensive overview of the links between climate benefits, co-benefits and types of GI, categorized along a green-grey continuum so that researchers/practitioners can find information according to their topic of interest. We further provide an analysis of trade-offs between various GI benefits. 'Bundles' of major co-benefits and trade-offs for each climate benefit can be identified with recommendations for strategies to maximize benefits and minimize trade-offs. To promote climate-resilient pathways through GI, it is crucial for decision-makers to identify opportunities to deliver multiple ecosystem services and benefits while recognizing disservices and trade-offs that need to be avoided or managed.

Rapid quantification of fecal indicator bacteria in water using the most probable number - loop-mediated isothermal amplification (MPN-LAMP) approach on a polymethyl methacrylate (PMMA) microchip

Fecal contamination of water and its associated pathogens are a major public health concern in both developing and industrialized areas. Fecal indicator bacteria (FIB) are commonly used to assess microbial water quality, but they require a relatively long period of incubation time. Currently, molecular techniques have been applied to rapidly detect FIB. However, these molecular techniques require expensive and sophisticated equipment. In this study, we developed a rapid on-chip gene quantification method based on loop-mediated isothermal amplification (LAMP) PCR. The LAMP assays can measure the target genes of the fecal indicator bacteria (FIB), including E. coli and Enterococcus spp, using the most probable number (MPN) approach. The colorimetric LAMP assay allows for naked-eye observation of the PCR reaction as few as 4 gene copies / well. When the reaction ends, MPN measurement of positive outcomes on the white-based PMMA (polymethacrylic acid) microchips provides the concentrations of the target genes of FIB with a confidence interval. We validated the feasibility of the MPN-LAMP approach by obtaining a strong correlation between the results of the MPN estimations and the qPCR analysis. Moreover, the MPN-LAMP approach was used to quantify the FIB in different environmental water collected from the freshwater reservoirs, beach, agriculture farm, and sewage. Our research demonstrates that the MPN- LAMP method enables us to easily and quickly quantifying FIB genes isolated from the environment without expensive qPCR instruments.

The tree cover and temperature disparity in US urbanized areas: Quantifying the association with income across 5,723 communities

Urban tree cover provides benefits to human health and well-being, but previous studies suggest that tree cover is often inequitably distributed. Here, we use National Agriculture Imagery Program digital ortho photographs to survey the tree cover inequality for Census blocks in US large urbanized areas, home to 167 million people across 5,723 municipalities and other Census-designated places. We compared tree cover to summer land surface temperature, as measured using Landsat imagery. In 92% of the urbanized areas surveyed, low-income blocks have less tree cover than high-income blocks. On average, low-income blocks have 15.2% less tree cover and are 1.5⁰C hotter than high-income blocks. The greatest difference between low- and high-income blocks was found in urbanized areas in the Northeast of the United States, where low-income blocks in some urbanized areas have 30% less tree cover and are 4.0⁰C hotter. Even after controlling for population density and built-up intensity, the positive association between income and tree cover is significant, as is the positive association between proportion non-Hispanic white and tree cover. We estimate, after controlling for population density, that low-income blocks have 62 million fewer trees than high-income blocks, equal to a compensatory value of $56 billion ($1,349/person). An investment in tree planting and natural regeneration of $17.6 billion would be needed to close the tree cover disparity, benefitting 42 million people in low-income blocks.

International Perceptions of Urban Blue-Green Infrastructure: A Comparison across Four Cities

Blue-Green infrastructure (BGI) is recognised internationally as an approach for managing urban water challenges while enhancing society and the environment through the provision of multiple co-benefits. This research employed an online survey to investigate the perceptions of BGI held by professional stakeholders in four cities with established BGI programs: Newcastle (UK), Ningbo (China), Portland (Oregon USA), and Rotterdam (The Netherlands) (64 respondents). The results show that challenges associated with having too much water (e.g., pluvial and fluvial flood risk, water quality deterioration) are driving urban water management agendas. Perceptions of governance drivers for BGI implementation, BGI leaders, and strategies for improving BGI uptake, are markedly different in the four cities reflecting the varied local, regional and national responsibilities for BGI implementation. In addition to managing urban water, BGI is universally valued for its positive impact on residents’ quality of life; however, a transformative change in policy and practice towards truly multifunctional infrastructure is needed to optimise the delivery of multiple BGI benefits to address each city’s priorities and strategic objectives. Changes needed to improve BGI uptake, e.g., increasing the awareness of policy-makers to multifunctional BGI, has international relevance for other cities on their journeys to sustainable blue-green futures.

Social Barriers and the Hiatus from Successful Green Stormwater Infrastructure Implementation across the US

Green stormwater infrastructure (GSI), a nature-inspired, engineered stormwater management approach, has been increasingly implemented and studied especially over the last two decades. Though recent studies have elucidated the social benefits of GSI implementation in addition to its environmental and economic benefits, the social factors that influence its implementation remain under-explored thus, there remains a need to understand social barriers on decisions for GSI. This review draws interdisciplinary research attention to the connections between such social barriers and the potentially underlying cognitive biases that can influence rational decision making. Subsequently, this study reviewed the agent-based modeling (ABM) approach in decision support for promoting innovative strategies in water management for long-term resilience at an individual level. It is suggested that a collaborative and simultaneous effort in governance transitioning, public engagement, and adequate considerations of demographic constraints are crucial to successful GSI acceptance and implementation in the US.

Can Allotment Gardens (AGs) Be Considered an Example of Nature-Based Solutions (NBS) Based on the Use of Historical Green Infrastructure?

The term nature-based solutions (NBSs) is understood as a multidisciplinary umbrella concept that includes aspects such as green/blue infrastructure and urban gardens and forests. However, the important question here is what features of ecosystem-based approaches are essential for them to be considered nature-based? This study aims to answer this question by analysing the potential of allotment gardens (AGs) to be considered as NBSs. To do so, the possibilities and obstacles regarding a Polish case study were analysed based on the following six research questions: (1) How do AGs use blue and green infrastructure? (2) What problem(s) do AGs solve today? (3) What kind of benefits do AGs provide? (4) Do AGs possess implementation and management capabilities? (5) Can AGs be treated as economically efficient? (6) What are the advantages of AGs versus other possible solution(s)? With regards to obstacles, the study has identified: institutional barriers, irregular distribution of benefits, and deficiencies in economic efficiency. Nevertheless, AGs together with other historical urban green/blue infrastructure may be regarded as a kind of unsophisticated NBS, the effectiveness of which is limited. These solutions may be created as independent structures or (historical) green/blue infrastructure may be enlarged, fitted out, linked, and improved to implement NBS projects.

A spatiotemporal analysis of urban resilience to the COVID-19 pandemic in the Yangtze River Delta

The COVID-19 pandemic has severely affected the normal socioeconomic operation of countries worldwide, causing major economic losses and deaths and posing great challenges to the sustainable development of cities that play a leading role in national socioeconomic development. The strength of urban resilience determines the speed of urban social and economic recovery. This paper constructed a comprehensive evaluation index system for urban resilience under the COVID-19 pandemic scenario considering four dimensions-economy, ecology, infrastructure, and social systems-conducted a quantitative evaluation of urban resilience in the Yangtze River Delta of China, revealed its spatiotemporal differences and change trends, and proposed targeted strategies for improving urban resilience. The results show that (1) the Yangtze River Delta urban resilience system is growing stronger every year, but there are significant differences in the level of urban resilience, its spatial distribution and regional urban resilience. (2) In the Yangtze River Delta urban agglomeration, there is less distribution of areas with a higher resilience index, while those with high and medium resilience levels are more distributed. However, the resilience of most cities is low. (3) The resilience index of eastern coastal cities is significantly higher, and the resilience of cities under the COVID-19 scenario presents obvious east-west differentiation. (4) When constructing urban resilience, the individual situation of cities should be taken into account, measures adjusted according to local conditions, reasonable lessons drawn from effective international urban resilience construction, and reasonable planning policies formulated; it is important to give play to the relationship between the whole and the parts of resilience to achieve unified and coordinated development.

Access and Use of Green Areas during the COVID-19 Pandemic: Green Infrastructure Management in the “New Normal”

This study aims to identify the influence of the socioeconomic attributes and environmental contexts of citizens’ residential areas on the access and use of green areas during the COVID-19 pandemic. The results can aid policymaking and facilitate the safe and unrestricted use of green areas during the pandemic. The access and use of green areas were analyzed using a survey conducted after the official COVID-19 emergency in Japan (16 April to 14 May, 2020). Visits to green areas during the pandemic have gained salience globally from multiple perspectives: health, planning, social justice, and equity. The results of this study demonstrated that socioeconomic factors influenced the frequency of visiting green areas. The factors further influenced the use of the three categories of green areas (parks, agricultural lands, and gardens). Environmental contexts, including the land use patterns in residential areas, also influenced the use of specific types of green areas. Thus, policies need to further facilitate visits to green areas by reflecting the socioeconomic attributes of residents and their households, including income, number of children, gender, and age, incorporating those who have less access and considering the spread of COVID-19 locally. Furthermore, policies for the use of specific green areas, including parks, agricultural lands, and gardens, need to take cognizance of the residents’ environmental contexts. Management of specific green areas, like agricultural lands, is required, and residents should be provided with opportunities to use these areas with measures to avoid infection.

Urban stormwater characterization, control, and treatment

This review summarizes over 280 studies published in 2019 related to the characterization, control, and management of urban stormwater runoff. A summary of quantity and quality concerns is provided in the first section of the review, serving as the foundation for the following sections which focus on the control and treatment of stormwater runoff. Finally, the impact of stormwater control devices at the watershed scale is discussed. Each section provides a self-contained overview of the 2019 literature, common themes, and future work. Several themes emerged from the 2019 literature including exploration of substrate amendments for improved water quality effluent from stormwater controls, the continued study of the role of vegetation in green infrastructure practices, and a call to action for the development of new models which generate reliable, computationally efficient results under the physical, chemical, biological, and social complexity of stormwater management. PRACTITIONER POINTS: Over 280 studies were published in 2019 related to the characterization, control, and treatment of urban stormwater. Studies on bioretention and general stormwater characteristics represented the two most common subtopics in 2019. Trends in 2019 included novel substrate amendments, studies on the role of vegetation, and advancements in computational models.

Knowledge, attitudes, intentions, and behavior related to green infrastructure for flood management: A systematic literature review

Green infrastructure (GI), which mimics natural hydrological systems, is a promising solution for flood management at the intersection of urban built infrastructure and natural systems. However, it has not yet achieved widespread uptake, due in part to insufficient understanding of human dimensions of the broader socio-ecological-technical system. We therefore conducted a multidisciplinary systematic literature review to synthesize research on people's existing knowledge about flood risk and GI, and how that shapes their attitudes and motivation to adopt new solutions. We systematically screened 21,207 studies on GI for flood management; 85 met our inclusion criteria. We qualitatively analyzed these studies to extract results on knowledge, attitudes, intentions, and behavior relating to GI for flood management. Overall, knowledge of GI was low across the 44 studies in which it was evaluated. Seventy studies assessed attitudes about GI, including the functional, aesthetic, health and safety, recreational, conservation, financial, and cultural value of GI, albeit their measurement was inconsistent. Willingness to implement or pay for GI varied considerably across 55 studies in which it was measured. Twenty studies measured and documented behavior relating to GI use, and these found low rates of adoption. Few studies systematically assessed the role of demographic, socio-economic, or geographic characteristics that could influence individuals' knowledge, attitudes, intentions or behavior, and thereby the success of GI programs. We recommend that researchers should more systematically capture data on human dimensions of GI (i.e. knowledge, attitudes, intentions, and behavior) across diverse settings to improve program design and uptake, especially among vulnerable populations. Greater attention to the social component of the socio-ecological-technical system will help ensure that GI programs are equitable, inclusive, and sustainable.

Using Different Levels of Information in Planning Green Infrastructure in Luanda, Angola

Integrating natural processes to build areas through the creation of green infrastructure (GI) in Africa with its rapid urbanisation is a challenge because of the information base. The aim of this paper is planning a GI linking biophysical, social, and legal contents in a specific Africa country with an approach that combines different scales and different levels of data and information. The paper proposes a framework beginning at the macro scale to integrate and operationalise the definition of GI in an African context, namely for the Luanda metropolitan area. The approach to nature and ecological structure (GI) has four phases: analysis, integration, diagnosis and proposal. All steps are developed in a GIS environment and consider variations in the biophysical, social, cultural, and legal dimensions. The research discusses the problems in collecting existing information and leads with missing data within the context of urbanisation growth and climate change adaptation. The proposed green infrastructure includes protected areas (existing and proposed), natural values, risk areas, rivers, and agricultural areas, to increase resilience and flexibility in an adaptation context. The results allow to include in the GI the mangrove areas, native flora, vegetated slopes, and riverbanks, providing a buffering function for natural hazards, crucial for these regions, with the aim to achieve the needs of creating a strategic GI to be implemented into the Luanda General Master Plan.

Cost-effectiveness Analysis of Green-Gray Stormwater Control Measures for Non-Point Source Pollution

The control of non-point source pollution (NPS) is an essential target in urban stormwater control. Green stormwater control measures (SCMs) have remarkable efficiency for pollution control, but suffer from high maintenance，operation costs and poor performance in high-intensity rainfall events. Taking the Guilin Road subwatershed in Rizhao, China, as a case study, a scheme for coupling gray and green stormwater control measures is proposed, and the gray SCMs are introduced to compensate for the shortcomings of green SCMs. The System for Urban Stormwater Treatment and Analysis Integration (SUSTAIN) model was employed to investigate the cost-effectiveness of three scenarios (green SCMs only, gray SCMs only, and coupled green-gray SCMs). The results show that the optimal solutions for the three scenarios cost USD 1.23, 0.79, and 0.80 million, respectively. The NPS control ability of the coupled green-gray scenario is found to be better than that of the other two scenarios under rainfall events above moderate rain. This study demonstrates that coupled green-gray stormwater control management can not only effectively control costs, but can also provide better pollution control in high-intensity rainfall events, making it an optimal scheme for effective prevention and control of urban non-point source pollution.

Stakeholders’ Engagement on Nature-Based Solutions: A Systematic Literature Review

Cities are facing a broad range of social and environmental challenges due to the current pressure of global urbanization. Nature-based solutions aim to utilize green infrastructure to improve people’s health and wellbeing. The design of urban environments must embrace the individual ideals of citizens and stakeholders which can only be achieved if effective methods of communication, involvement, and feedback are ensured. Such a procedure creates trust during its implementation, helping to take ownership and stewardship of processes and sites. This systematic literature review explores the current state of the art regarding citizen and stakeholder participation in nature-based solutions (NBS). The search on the SCOPUS database identified 142 papers in total that met the inclusion criteria. The participation analysis was separated in two areas: (a) analysis of perceptions, preferences, and perspectives of citizens and stakeholders, and (b) analysis of the participation process, including challenges and opportunities, motivations, methods and frameworks, and collaborative governance. The results revealed that stakeholder and citizen participation or collaboration in nature-based solutions is increasingly recognized as promising; however, research in several related domains is still lacking.

Green Infrastructure Solutions to Health Impacts of Climate Change: Perspectives of Affected Residents in Detroit, Michigan, USA

Cities worldwide are incorporating green infrastructure to mitigate climate change and achieve health cobenefits. However, green infrastructure projects are often distributed inequitably based on race and class. Residents’ perspectives are necessary to develop and enact effective and equitable ‘green’ strategies to address climate change and its health impacts. This study reports findings from interviews and ethnographic observations with diverse residents of Detroit, Michigan, USA, who have experience with both green infrastructure projects and intense weather events (flooding). Residents expressed widespread support for green infrastructure solutions, while also sharing concerns about unintended health consequences from unsatisfactory governance of green spaces and climate change itself. Residents also held differing perspectives regarding their responsibility for, and capacity to enact, these solutions compared to businesses, city government, and nonprofit organizations. These findings illuminate key factors that city governments and partnering institutions should incorporate into planning processes with residents to achieve greater environmental justice through green infrastructure strategies to mitigate climate change and related health impacts.

Development Trend and Frontier of Stormwater Management (1980–2019): A Bibliometric Overview Based on CiteSpace

The threat of urban floods due to climate change and urbanization has enabled sustained attention to the stormwater management field. Numerous scholars and countries have successively proposed innovative concepts for stormwater management. To grasp the current research focus and status quo and determine the development trend and dynamic direction, this work used CiteSpace, a scientific bibliometric analysis software, to analyze and identify 3080 articles based on the core database of Web of Science from 1980 to 2019. Results show a comprehensive overview of the stormwater management field, including the changes of annual articles with time; the most influential countries, institutions, authors, and articles; and the periodical keywords, highly cited papers, and burst time in the field. A knowledge table in the stormwater management field was obtained, the development context of the field and the research focus of each stage were understood, and the future development trend of the field is inferred. This study aims to provide reference for researchers and practitioners in the stormwater management field.