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1.
Stormwater Green Infrastructure (SGI) systems such as rain gardens, permeable pavement and bioswales are commonly used in municipalities to reduce urban flooding and water pollution. In conjunction with these direct benefits, SGI systems provide additional social and environmental “co-benefits”. Our goal was to investigate the co-benefits of commonly used SGI systems in five cities in the United States, including Baltimore, Denver, New York City, Philadelphia, and Portland. The i-Tree Eco model was used to predict carbon storage and sequestration, air pollution removal, UV reduction, and cooling effects of trees for individual tree species and estimated SGI tree inventories across the five study cities based on observed tree characteristic data. Aspects of SGI design, environmental factors, and model inputs were assessed to understand what parameters impacted SGI co-benefits predicted by the model. We evaluated the most highly influential parameters using a global sensitivity analysis method. As expected, the type of SGI design, and the overall number of trees utilized within those designs, played a large role in determining the overall amount of co-benefits predicted by the model. However, climate also influenced estimation of benefits produced, with similar responses predicted for cities in the same climate zone (e.g. Baltimore, Philadelphia, and New York City). In particular, the global sensitivity analysis showed that variables influencing environmental conditions and tree growth also impacted final co-benefit predictions produced by i-Tree Eco. study revealed how various assumptions and prevailing equations within the i-Tree Eco model can play a major role in the final outcomes predicted by the model. Studies that use i-Tree Eco to analyze potential co-benefits of SGI projects, especially when the goal is to compare projects across climate zones, should consider what aspects of the results are simply a function of the model itself. Overall, the model predicts that more co-benefits are provided in certain climate zones, an assumption currently supported in the literature. 相似文献
2.
Establishment of roadside plantings is often limited by adverse site conditions, particularly poor soil physical and chemical properties. We compared plant establishment of shrubs, herbaceous perennials, and grasses in response to addition of compost and/or tillage before planting in replicated plots at two locations along an interstate highway near Detroit, MI, USA. Plots at each location received one of four site preparation treatments: control (no treatment), compost only (top-dressed with 8 cm of municipal compost), tillage only (soil tilled to 20 cm) or compost + tillage (8 cm of compost added and tilled to 20 cm). Within each site preparation plot, we established sub-plots of 16 selections of shrubs, perennials, and ornamental grasses. Compost addition, plant selection, and location affected (P ≤ 0.05) plant survival, height growth, and % plant cover two years after planting. Tillage did not affect (P > 0.05) plant establishment. Similarly, the interaction of tillage × compost was not significant, indicating that surface application of compost was as effective as tilling compost into the soil. Improved plant establishment with the addition of compost was associated with improved soil and plant nutrition and reduced soil pH and soil bulk density. Within each plant group (i.e., shrubs, perennials, grasses) plant establishment varied widely. Overall, the results indicate that compost addition can improve establishment of diverse roadside plantings, which was associated with improved soil fertility. In contrast, tillage provided comparatively little benefit to plant performance in this trial. 相似文献
3.
The rapid growing urbanization is one of the main threats to urban biodiversity and the ecosystem services (ES) that they provide. Pollination is one of the most affected ES in urban areas mainly due to the decline in urban green areas (UGAs) and other factors derived from urbanization itself. Considering this and the already existing global pollinator crisis, the aim of this work is the evaluation of urban green infrastructure as an opportunity for pollinator conservation. For that purpose, the ornamental vegetation of a medium-sized Mediterranean city (Granada, south-eastern Spain) was determined. The floral origin, phenology and floral traits of the conforming species and the pollinator species that they attract were analysed. Additionally, NMDS analysis were performed in order to determine if the “Pollination Syndromes” are a useful tool to actually predict the pollinator group attracted to a certain plant species. It was found that UGAs have huge potential for pollinator conservation as the major part of its ornamental species have an entomophilic pollination strategy. However, there is an imbalance in the availability of flower resources throughout the year. Hence, the addition of species flowering out of the main flowering season would be advisable in order to get a continuous supply of floral resources for pollinators. A current disproportion in the potentially attracted pollinator groups was also found out, being bees the predominantly attracted ones. However, results showed that the “Pollination Syndromes” are a tool with limitations at the moment and needs to be used with considerations. Thus, the specific plant-pollinator relationship should be determined through field work in each case-study. Further studies considering key factors such as urban connectivity and fragmentation would be desirable to ensure a comprehensive management for urban pollinators. 相似文献
4.
Increasing urbanization, impervious space, and the impact of climate change are threatening the future of cities. Nature-based solutions, specifically urban green infrastructures, are seen as a sustainable strategy to increase resilience against extreme weather events, including the escalating occurrence of stormwater runoff flooding. Consequently, urban planners and decision-makers have pushed their efforts toward implementing green infrastructure solutions to reduce the impact of stormwater floods. Among others, green roofs help store water and decrease stormwater runoff impacts on a local scale. This research aims to investigate the effect of surface permeability and green roof implementation on reducing stormwater flooding and subsequently provide urban planners with evidence-based geospatial planning recommendations to improve urban resilience in Helsinki. First, we modeled the current impact of stormwater flooding using the Arc-Malstrom model in Helsinki. The model was used to identify districts under high stormwater flood risk. Then, we zoomed in to a focus area and tested a combination of scenarios representing four levels of green roof implementation, two levels of green roof infiltration rates under 40-, 60-, 80-, 100 mm precipitation events on the available rooftops. We utilized open geographic data and geospatial data science principles implemented in the GIS environment to conduct this study. Our results showed that low-level implementation of green roofs with low retention rates reduces the average flood depth by only 1 %. In contrast, the maximum green roof scenario decreased most of the average flood depth (13 %) and reduced the number of vulnerable sites. The proposed methodology can be used for other cities to develop evidence-based plans for green roof implementations. 相似文献
5.
Urban stormwater is a major contributor to surface water degradation in the United States, prompting cities to invest in ways to naturally capture, store, and slowly release runoff through green infrastructure (GI). An often overlooked, yet integral, component of GI is urban tree canopy, which functions as GI through the process of rainfall interception (i.e., rainfall captured and stored within the canopy prior to returning to the atmosphere via evaporation). Nine trees from three native species commonly found in urban areas in the southeastern United States were studied in three parks in Knoxville, TN, USA to quantify interception. Throughfall (rainfall that passes through the canopy) and stemflow (rainfall that travels down the trunk) data were collected with continuous measurements by a network of automatic rain gauges positioned underneath each tree canopy. Data were collected from January 2018 to May 2019 which resulted in 98 storm events collected for each red maple (Acer rubrum) and willow oak (Quercus phellos), and 97 storm events collected for each white pine (Pinus strobus). Annually, red maples, white pines, and willow oaks intercepted 24.4%, 52.4%, and 33.2% of gross throughfall, respectively. Seasonally, white pines performed the most consistently with interception varying only from 49.2% to 57.0% between seasons compared to an interception range of 13.2–39.7% and 17.5–54.2% for red maples and willow oaks, respectively. Results demonstrated the effect of event duration, rainfall intensity, and seasonality on the interception potential of each species. Overall, these observations are a step toward allowing the storage capacity of urban trees to be properly credited as part of efforts to reduce stormwater runoff. 相似文献
6.
Urban forests are recognized as a nature-based solution for stormwater management. This study assessed the underlying processes and extent of runoff reduction due to street trees with a paired-catchment experiment conducted in two sewersheds of Fond du Lac, Wisconsin. Computer models are flexible, fast, and low-cost options to generalize and assess the hydrologic processes determined in field studies. A state-of-the-art, public-domain model, which explicitly simulates urban tree hydrology, i-Tree Hydro, was used to simulate the paired-catchment experiment, and results from field observations and simulation predictions were compared to assess model validity and suitability as per conditions in the broader Great Lakes basin. Model parameters were aligned with observed conditions using automatic and manual calibration. Model performance metrics were used to quantify the weekly performance of calibration and to validate predictions. Those calibration metrics differed substantially between the two periods simulated, but most calibration metrics remained positive, indicating the model was not fitting only the period used for calibration. Predicted avoided runoff for a five-month leaf-on period was 64 L/m2 of canopy, 4 % lower than the field-estimated avoided runoff of 66 L/m2 of canopy. Interception was the most directly comparable process between the model and field observations. Based on 5 storms sampled, field estimation of precipitation intercepted and retained on trees averaged 63 % and ranged from 22 % to 81 %, while model estimation averaged 61 % and ranged from 36 % to 99 %. This model was able to fit predictions to observed catchment discharge but required extensive manual calibration to do so. The i-Tree Hydro model predicted avoided runoff comparable with the field study and earlier assessments. Additional field studies in similar settings are needed to confirm findings and improve transferability to other tree species and environmental settings. 相似文献
7.
Urbanization modifies the landscape with green and blue spaces (GBS), which further leads to a functional change along an urban-rural gradient. Emotional improvement is a critical service of GBS, which may be perceived and exposed through facial expressions by visitors. How people react, however, may vary at different locations of a city at varied phases of urbanization. In this study, happy and sad emotions were rated as scores from 7965 Sina-Weibo users who visited 77 GBS across 49 cities of East China in 2020. GBS were located in different regions of a city, either near downtown or in more rural-like regions. Compared to cities near the Hu Huanyong line, those along the eastern coast were built with parks that had smaller green spaces at lower elevations in locations near downtown. They also had larger blue spaces in parks at suburban areas of the same cities. People expressed more happiness in GBS in regions closer to remote rural regions, or in cities further from the eastern coast. Larger green spaces were associated with by the presentation more smiles in parks near downtown, while experiences in large blue spaces evoked positive emotions at suburban areas. Overall, GBS in population-dense regions of more developed cities can be perceived as an activation of exposing higher depression by visitors. More smiles can be exposed in GBS with a large green space near downtown, or with a large blue space at suburban regions of a city in East China. 相似文献
8.
Since early 2020, Coronavirus Disease 2019 (COVID-19) has spread rapidly, quickly becoming a global pandemic. To counter the COVID-19 outbreak, national governments have issued different measures and restrictions, forcing citizens to adapt to a whole new lifestyle. These restrictions have impacted on the use of green spaces by citizens owing to many factors: more available free time, increased flexibility in the work environment, and a need to relax in Nature to relieve anxiety and stress. Urban green spaces provide many benefits for the physical and psychological well-being of citizens (e.g., habitat conservation, pollution control, recreational and leisure opportunities). To understand if citizens’ habits have changed due to the COVID-19 restrictions, this study provides insights from a web-based survey monitoring the use of such spaces before and during the COVID-19 lockdowns in Italy. A web-based questionnaire was conducted via “Facebook Messenger” and “WhatsApp” at the end of the second wave of COVID-19 (May–June 2021). Data collection having been concluded, 1075 completed questionnaires were collected and processed. The results show that while many reduced their weekly frequentation of green areas (−16.5%), the number of people frequenting green areas near their home every day increased (+7.7%). Two main groups of people were identified: the first, those who intensified their visits to green areas being those who desired to spend time in contact with Nature; the second, those who were reluctant to visit green areas for fear of being infected. The results also show most of the respondents felt urban green areas were either very important (82.1%) or important (14.4%). Overall, the results reveal that COVID-19 induced a positive perception of the benefits provided by urban green areas, with a consequent greater use of them, which seems destined to last even once the public health emergency has passed. 相似文献
9.
Modern cities are dominated by impervious surfaces that absorb, store and release heat in summer, create large volumes of runoff and provide limited biodiversity habitat and poor air quality can also be a health issue. Future climate change, including more frequent and extreme weather events will likely exacerbate these issues. Green infrastructure such as parks, gardens, street trees and engineered technologies such as green roofs and walls, facades and raingardens can help mitigate these problems. This relies on selecting plants that can persist in urban environments and improve stormwater retention, cooling, biodiversity and air pollution. However, plant selection for green infrastructure is challenging where there is limited information on species tolerance to heat and water variability or how these species can deliver multiple benefits. Therefore, we draw on research to illustrate how plant performance for green infrastructure can be inferred from plant attributes (i.e., traits) or from analysis of their natural distribution. We present a new framework for plant selection for green infrastructure and use a case study to demonstrate how this approach has been used to select trees and shrubs for Australian cities. We have shown through the case study and examples, how plant traits and species’ natural distribution can be used to overcome the lack of information on tolerance to both individual and multiple stressors; and how species contribute to the provision of benefits such as stormwater retention, cooling, biodiversity and air pollution mitigation. We also discuss how planting design and species diversity can contribute to achieving multiple benefits to make the most of contested space in dense cities, and to also reduce the risk of failure in urban greening. 相似文献
10.
Green roofs provide a number of different urban ecosystem services (UESS), e.g. regulation of microclimate, support of air quality improvement, or stormwater retention. To estimate the spatial variation of green roof UESS across an urban area, a GIS-based mapping and spatial analysis methodology was established and applied to the city of Braunschweig, Germany. Based on the analysis of available geodata, in a first step, a quantity of 14,138 rooftops in the study area (14% of all buildings) was found to be generally suitable for greening. This resulted in a green roof area of 3 km2. Based on criteria such as roof slope and minimum roof size, nearly two-thirds of these buildings (8596 buildings, 8.6% of total number of buildings) were categorised ‘appropriate’ for greening and subject to green roof UESS analysis.The spatial distribution of green roof UESS was estimated based on the categories thermal urban climate, air quality, stormwater retention and biodiversity. Due to their potential benefits in the four UESS categories an overall assessment resulted in a number of 867 roofs (0.9% of total number of buildings) categorised as ‘high benefit’ from rooftop greening. Another 3550 buildings (3.5%) and 4179 buildings (4.2%) were defined as ‘moderate benefit’ and ‘low benefit’, respectively. The inner city area of Braunschweig appears as a hot-spot of green roof UESS, i.e. higher percentage of ‘high benefit’ green roofs in comparison to residential areas. The proposed method is a simple but straightforward approach to analyse urban green roof UESS and their spatial distribution across a city but it is sensitive to the quality of the available input geodata. 相似文献
11.
Judith A. Simon Joel W. Snodgrass Ryan E. Casey Donald W. Sparling 《Landscape Ecology》2009,24(3):361-373
Many amphibian species rely on both aquatic and terrestrial habitats to complete their life cycles. Therefore, processes operating both within the aquatic breeding habitat, and in the surrounding uplands may influence species distributions and community composition. Moreover, changes in land use adjacent to breeding site may degrade aquatic habitats. To assess land use effects on pond-breeding amphibian assemblages, we investigated relationships between land use, breeding habitat conditions, and breeding amphibian use of constructed wetlands in urban environments of the Baltimore metropolitan area, USA. Forest and impervious surface associations with species richness and occurrence occurred at spatial scales ranging from 50 to 1,000 m, with strongest relationships at 500 m. Forest and impervious surface cover within 1,000 m of ponds were also related to water and sediment quality, which in turn were capable of explaining a proportion of the observed variation in species richness and occurrence. Taken together, our results suggest that forest and other land covers within relatively proximal distances to ponds (i.e., within 50–1,000 m) may be influencing species richness directly via the provisioning of upland habitat, and indirectly via influences on within pond habitat quality. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Plant selection for rain gardens along streets and roads in cold climates can be complicated, as the plants are subjected to combined stresses including periodic inundation, de-icing salts, road dust, splashes of water from the road, freezing and thawing of soil, and periods with ice cover during the winter. The purpose of this study was to identify species suited to grow in these conditions and determine their optimal placement within roadside rain gardens. Thirty-one herbaceous perennial species and cultivars were planted in real-scale rain gardens in a street in Drammen (Norway) with supplemental irrigation, and their progress was recorded during the following three growing seasons. The study highlights considerable differences between species’ adaptation to roadside rain gardens in cold climates, especially closest to the road. Some candidate species/cultivars had a high survival rate in all rain garden positions and were developed well. These were: Amsonia tabernaemontana, Baptisia australis, Calamagrostis × acutiflora ‘Overdam’, Hemerocallis ‘Camden Gold Dollar’, Hemerocallis ‘Sovereign’, Hemerocallis lilioasphodelus, Hosta ‘Sum & Substance’, Iris pseudacorus and Liatris spicata ‘Floristan Weiss’. Other species/cultivars appeared to adapt only to certain parts of the rain garden or had medium tolerance. These were: Calamagrostis brachytricha, Carex muskingumensis, Eurybia × herveyi ‘Twilight’, Hakonechloa macra, Hosta ‘Francee’, Hosta ‘Striptease’, Liatris spicata ‘Alba’, Lythrum salicaria ‘Ziegeunerblut’, Molinia caerulea ‘Moorhexe’, Molinia caerulea ‘Overdam’, and Sesleria autumnalis. Species/cultivars that showed high mortality and poor development at all rain garden positions should be avoided in roadside cold climate rain gardens. These include Amsonia orientalis, Aster incisus ‘Madiva’, Astilbe chinensis var. tacquettii ‘Purpurlanze’, Chelone obliqua, Dryopteris filix-mas, Eurybia divaricata, Geranium ‘Rozanne’, Helenium ‘Pumilum Magnificum’, Luzula sylvatica, Polygonatum multiflorum and Veronicastrum virginicum ‘Apollo’. The study also found considerable differences between cultivars within the same species, especially for Hosta cvv. and Liatris spicata. Further investigations are needed to identify the cultivars with the best adaption to roadside rain gardens in cold climates. 相似文献
13.
This paper presents results from a container experiment and a real-scale study in road environments for evaluating the performance of soil mixtures and herbaceous perennials for use in rain gardens. The container experiment included 12 soil mixtures and 4 perennial species. The plants were exposed to three flooding events and one drought period, and their overall vitality was recorded after the floodings. The containers were stored outdoors the following winter and plant survival was observed in spring. Amsonia orientalis did not survive the winter after being exposed to flooding in the growing season and was replaced by Hosta ‘Francee’ in the real-scale study, which was established in Drammen (Norway) in a soil mixture based on optimisation of the best mixtures in the container experiment. Luzula sylvatica performed well in the container study and survived the winter; however, in the field study, individuals of this species that were located close to the road died due to de-icing salt. Eurybia divaricata showed some mortality in both studies, and total mortality occurred in individuals that were close to the road, due to de-icing salt. Hemerocallis cvv. performed well in both experiments and appeared to be useful in all rain garden positions in the cold climate road environment. H. ‘Francee’ developed well in the road environment, except when exposed to splashes of road water. The study highlights considerable differences between species’ adaption to roadside rain gardens in cold climates, and the need for further field investigations. 相似文献
14.
Sara lvarez Alejandra Navarro Sebastin Ban M. Jesús Snchez-Blanco 《Scientia Horticulturae》2009,122(4):579-585
The purpose of this study was to analyze the physiological and morphological response of carnation plants to different levels of irrigation and to evaluate regulated deficit irrigation as a possible technique for saving water through the application of controlled drought stress. Carnations, Dianthus caryophyllus L. cultivar, were pot-grown in an unheated greenhouse and submitted to two experiments. In the first experiment, the plants were exposed to three irrigation treatments: (control); 70% of the control (moderate deficit irrigation, MDI) and 35% of the control (severe deficit irrigation, SDI). In the second experiment, the plants were submitted to a control treatment, deficit irrigation (DI, 50% of the control) and regulated deficit irrigation (RDI). After 15 weeks, MDI plants showed a slightly reduced total dry weight, plant height and leaf area, while SDI had clearly reduced all the plant size parameters. RDI plants had similar leaf area and total dry weight to the control treatment during the blooming phase. MDI did not affect the number of flowers and no great differences in the colour parameters were observed. RDI plants had higher flower dry weight, while plant quality was affected by the SDI (lower number of shoots and flowers, lower relative chlorophyll content). Leaf osmotic potential decreased with deficit irrigation, but more markedly in SDI, which induced higher values of leaf pressure. Stomatal conductance (gs) decreased in drought conditions more than the photosynthetic rate (Pn). Osmotic adjustment of 0.3 MPa accompanied by decreases in elasticity in response to drought resulted in turgor less at lower leaf water potentials and prevented turgor loss during drought periods. 相似文献
15.
Greening cities is of considerable significance to creating sustainable cities. Cost-benefit analyses have shown that urban green is not only ecologically and socially desirable but also economically advantageous. However, maintaining this urban green is becoming challenging due to changing climatic conditions. With frequent heat-waves, droughts and increasing water scarcity in many regions, it is crucial to establish systematic approaches to economise the available water used for irrigation. Currently, cities rely on rough approximations to assess irrigation demand. To address this gap, a linear time series model was developed based on soil water balance and Water Use Classifications of Landscape Species approach. The model uses publicly available data regarding trees, soil, and current and forecasted weather to estimate the irrigation demand of urban street trees on a weekly time scale. The developed model is applied in a case study of a metropolis in a moderate continental climate. The results show more distributed irrigation demand than the currently implemented soil moisture based model of the case study city. Accordingly, the model can support the decision-makers to not only assess the irrigation demand of existing trees but also help in water budgeting of new plantation under varying climatic conditions. 相似文献
16.
Raingardens are increasingly common in sustainable stormwater management in cities around the world. Implementing raingardens will change the appearance of conventional urban streetscapes and this is especially important when retrofitting raingardens into existing streets. Raingardens need to fulfil both technical and aesthetic functions. Aesthetic function, assessed as landscape preference, must be understood to ensure that retrofitted raingardens are appropriately designed and managed. Scholars have long adopted a Likert rating scale- to determine landscape preference. Limitations of this method led market researchers to develop choice-based ranking, including best-worst scaling, to assess preference. Thus, this study uses best-worst scaling to assess landscape preference by residents for pairs of streetscapes with and without raingardens in four suburbs of Melbourne, Victoria, Australia. These preference data, and attitudes towards raingardens, stormwater harvesting and own streetscapes, inform guidelines for design and management of retrofitted raingardens. Findings revealed respondents’ overwhelming support for harvesting and reuse of stormwater, though support for fit-for-purpose stormwater reuse decreased as personal proximity increased. While attitudes towards raingardens were positive and most respondents liked the raingardens in their own street, less than one-quarter helped to maintain them. Across all respondents, maintenance of raingardens in streetscapes was regarded as the responsibility of local government. Nevertheless, many would install raingardens in their own property. Overall, streetscapes with raingardens were preferred to those without. Residency in a street with or without raingardens did not influence preference, however, residency in a particular street did. Indeed, context was important: preference for one’s own streetscape varied statistically significantly between residents of inner- and outer-Melbourne suburbs. Drawing on these results, four guidelines for design and management of retrofitted raingardens are proposed: 1. Understand context; 2. Consider how the street is used; 3. Select appropriate plants and planting style; 4. Ensure adequate maintenance. 相似文献
17.
研究了北京市密云县西沟林场封山育林地区不同封育措施灌木林地土壤物理性状和土壤渗透性能.结果表明:在封造、封禁、封育3种封育措施的灌木林地中,土壤容重为:封造灌木林地>封禁灌木林地>封育灌木林地,土壤总孔隙度、非毛管孔隙度、毛管孔隙度、饱和蓄水量、有效涵蓄量、毛/饱和蓄水量的顺序为:封造灌木林地<封禁灌木林地<封育灌木林地.封育灌木林地土壤初始入渗速率是封禁灌木林地的1.45倍,是封造灌木林地的1.85倍.前30 min累积入渗量顺序为:封育灌木林地>封禁灌木林地>封造灌木林.从土壤物理性状和渗透性能来看,封育措施能更好的改良土壤结构、降低土壤容重和增加土壤总孔隙度,提高灌木林土壤水源涵养和理水调洪功能. 相似文献
18.
In the last decades, urban sprawl and soil sealing led to an increase of urban flooding phenomena. Sustainable Drainage Systems (SuDS) seem able to weaken stormwater-related criticalities, enhancing sustainability and city resilience.Relying on a detailed and feasible preparatory study of SuDS feasible retrofit design, based on a punctual identification of the areas suitable for retrofitting and the most appropriate combination of SuDS technologies, the reported research aimed to assess the effectiveness of a sustainable drainage approach in Sesto Ulteriano (Italy), an urban catchment suffering from stormwater management concerns. In particular, using the approach of a typical scenario analysis, this comparative modeling analysis involved SWMM5 for the assessment of the differences in the catchment hydrological behaviour between the mentioned specific and feasible SuDS retrofitting scenarios and a potential one, where non-specificity is considered for SuDS retrofitting location. Besides, the analyses focused on investigating how rainfall severity, areal extension and land use typical feature could influence the effectiveness of the sustainable redevelopment of the urban area.Results indicate that SuDS projects based on potential designs, which does not account for the feasible suds location, might result in a significant overestimation of the hydrological benefit. They showed, indeed, an improved hydrological performance, with average total volume reductions of the Combined Sewer Overflows up to over 70 % (retrofitting the 8.3 % of the catchment area), that is about 40 % higher than those obtained under the same areal extension by the feasible scenarios. Moreover, it was found that there could be an optimal SuDS retrofitting percentage above which additional hydrological benefits are undetectable. Land use, resulting in the variability in the degree of imperviousness necessarily associated to a variability in the retrofitting potential, also seemed to affect SuDS hydrological performance and for this reason should be included in an overall assessment. SuDS also proved to act successfully on the actual maximum percentage of nodes of the drainage network above a 0.7 filling degree threshold (about 52 % under 10-year return period rainfall) reducing it to 24 % with a feasible retrofitting involving the 8.3 % of the study area. 相似文献
19.
A cross-sectional analysis among 1041 urban residents was done to examine associations between self-reported walking distance to and use of freshwater urban blue space and health-related quality of life in two German cities: a city with “poor” urban blue space supply (Bielefeld; 0.8% blue space) and one with “better” urban blue space supply (Gelsenkirchen; 3.0% blue space). Health-related quality of life was assessed with the SF-12v2, which measures residents’ self-reported mental and physical health. Results showed a significant association between use frequency and perceived walking distance to blue space. Blue space use was a better indicator of health outcomes than perceived walking distance. After controlling for green space, socio-economic and demographic variables, use frequency was associated with higher mental health in Gelsenkirchen. These cross-sectional findings suggest that blue space use increases the probability of being healthier in highly urbanised areas in cities with an appropriate amount of blue space. 相似文献