40 research outputs found

    Maximizing Green Infrastructure in a Philadelphia Neighborhood

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    While the Philadelphia Water Department (PWD) is counting on Green Stormwater Infrastructure (GI) as a key component of its long-term plan for reducing combined sewer overflows, many community stakeholders are also hoping that investment in greening can help meet other ancillary goals, collectively referred to as sustainable redevelopment. This study investigates the challenges associated with implementation of GI in Point Breeze, a residential neighborhood of South Philadelphia. The project team performed a detailed study of physical, social, legal, and economic conditions in the pilot neighborhood over the course of several years, culminating in the development of an agent-based model simulation of GI implementation. The model evaluates a) whether PWD’s GI goals can be met in a timely manner, b) what kinds of assumptions regarding participation would be needed under different theoretical GI policies, and c) the extent to which GI could promote sustainable redevelopment. The model outcomes underscore the importance of private land in helping PWD achieve its GI goals in Point Breeze. Achieving a meaningful density of GI in the neighborhoods most in need of sustainable redevelopment may require new and creative strategies for GI implementation tailored for the types of land present in those particular communities

    Analysing stormwater temperature at site-specific discharge points along the Liesbeek River, South Africa

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    Increased urban development has resulted in increased impervious landcover and the removal of natural vegetation. The continued anthropic modification of the Earth's surface towards an urban state, has had profound effects on the surrounding natural systems (Thompson et al., 2008). Consequently, recent studies have highlighted a strong link between expanding urbanisation and thermal impacts on streams and rivers draining urban catchments (Roa-Espinosa et al., 2003; Arrington, 2003; Herb et al., 2009b). Anthropogenic perturbations such as thermal pollution can adversely disturb the natural thermal regime of a river (Boothe and Bledsoe, 2009). An important source of thermal pollution is thermally enriched stormwater runoff. During a rainfall event, runoff temperature is elevated as it makes contact with, and passes over surfaces which have a large heat storage capacity, such as pavements, roofs and roads (Young et al., 2013). However, the extent of impervious surfaces and resulting thermal pollution produced by them is poorly understood, although it is thought to be a major contributor to stream degradation. Previous research has focused on investigating the thermal effects of removing riparian vegetation. Additionally, a recent research approach has been to develop models of the urban surface-water-atmosphere systems. Finally, research in the field of fresh-water ecology has investigated the effects of temperature on aquatic biota. Water temperature affects all aspects of freshwater ecosystems and plays an important role in regulating physical and biological characteristics of a river (Olsen et al. 2011). Consequently, any anthropogenic modification to temperature can have devastating effects on the ecological functioning of a river and biodiversity of species within the river habitat. Important findings by Young et al. (2013) suggest the need for a detailed study of stormwater temperature changes in relation to rainfall events, at a catchment scale. Furthermore, data is required to show the point source effects of stormwater runoff from impervious surfaces on the temperature of the receiving water body. Therefore, the aim of this study is: To determine the extent and risk of thermal pollution at site specific discharge points, along the Liesbeek River. In order to achieve this aim, variables which cause temperature variations needed to be identified. The primary research method makes use of Thermocron iButton Temperature Loggers. These were placed in four stormwater outlet pipes, which frequently discharge event-based stormwater runoff into the Liesbeek River. Additionally, iButton loggers were placed in the river channel, to provide a reference temperature to compare stormwater discharge temperature. In addition, hourly rainfall and air temperature was acquired from the South AfricanWeather Service (SAWS) and was used in conjunction with the iButton temperature data

    Siting Urban Agriculture as a Green Infrastructure Strategy for Land Use Planning in Austin, TX

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    Green infrastructure refers to a type of land use design that mimics the natural water cycle by using the infiltration capacities of vegetation, soils, and other natural processes to mitigate stormwater runoff. As a multifunctional landscape, urban agriculture should be seen as a highly beneficial tool for urban planning not only because of its ability to function as a green stormwater management strategy, but also due to the multiple social and environmental benefits it provides. In 2012, the city of Austin adopted a major planning approach titled the “Imagine Austin Comprehensive Plan” (IACP) outlining the city’s vision for future growth and land use up to 2039. The plan explicitly addresses the adoption of green infrastructure as a target for future land use with urban agriculture as a central component. Addressing this area of land use planning will require tools that can locate suitable areas within the city ideal for the development of green infrastructure. In this study, a process was developed to create a spatially explicit method of siting urban agriculture as a green infrastructure tool in hydrologically sensitive areas, or areas prone to runoff, in east Austin. The method uses geospatial software to spatially analyze open access datasets that include land use, a digital elevation model, and prime farmland soils. Through this method a spatial relationship can be made between areas of high surface runoff and where the priority placement of urban farms should be sited as a useful component of green infrastructure. Planners or geospatial analysts could use such information, along with other significant factors and community input, to aid decision makers in the placement of urban agriculture. This spatially explicit approach for siting potential urban farms, will support the integration of urban agriculture as part of the land use planning of Austin

    TEMPORAL TRENDS IN THE SPATIAL DISTRIBUTION OF IMPERVIOUS COVER RELATIVE TO STREAM LOCATION

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    Use of impervious cover is transitioning from an indicator of surface water condition to one that also guides and informs watershed planning and management, including Clean Water Act (33 U.S.C. §1251 et seq.) reporting. Whether it is for understanding surface water condition or planning and management, impervious cover is most commonly expressed as summary measurement (e.g., percentage watershed in impervious cover). We use the National Land Cover Database to estimate impervious cover in the vicinity of surface waters for three time periods (2001, 2006, 2011). We also compare impervious cover in the vicinity of surface waters to watershed summary estimates of impervious cover for classifying the spatial pattern of impervious cover. Between 2001 and 2011, surface water shorelines (streams and water bodies) in the vicinity of impervious cover increased nearly 10,000 km. Across all time periods, approximately 27% of the watersheds in the continental United States had proximally distributed impervious cover, i.e., the percentage of impervious cover in the vicinity of surface waters was higher than its watershed summary expression. We discuss how impervious cover spatial pattern can be used to inform watershed planning and management, including reporting under the Clean Water Act

    PARAMETRIC APPROACHES TO BALANCE STORMWATER MANAGEMENT AND HUMAN WELLBEING WITHIN URBAN GREEN SPACE

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    Through rapid urbanisation, urban green spaces (UGS) have become increasingly limited and valuable in high-density urban environments. However, meeting the diverse requirements of sustainable urban development often leads to conflicts in UGS usage. For example, the presence of stormwater treatment facilities may hinder residents' access to adjacent UGS. Traditional approaches to UGS design typically focus on separate evaluations of human wellbeing and stormwater management. However, using questionnaires, interviews, and surveys for human wellbeing evaluation can be challenging to generalise across different projects and cities. Additionally, professional hydrological models used for stormwater management require extensive knowledge of hydrology and struggle to integrate their 2D evaluation methods with 3D models. To address these challenges, this thesis proposes a novel framework to integrate the two types of analysis within a system for balancing the needs of human wellbeing and stormwater management in UGS design. The framework incorporates criteria and parameters for evaluating human wellbeing and stormwater management in a 3D model and introduces an approach to compare these two needs in terms of UGS area and suitable location. The contributions of this thesis to multi-objective UGS design are as follows: (1) defining human wellbeing evaluation through Accessibility and Usability assessment, which considers factors such as connectivity, walking distance, space enclosure, and space availability; (2) simplifying stormwater evaluation using particle systems and design curves to streamline complex hydrological models; (3) integrating the two evaluations by comparing their quantified requirements for UGS area and location; and (4) incorporating parameters to provide flexibility and accommodate various design scenarios and objectives. The advantages of this evaluation framework are demonstrated through two case studies: (1) the human wellbeing analysis based on spatial parameters in the framework shows sensitivity to site variations, including UGS quantity and distribution, population density, terrain, road context, height of void space, and more; (2) the simplified stormwater analysis effectively captures site variations represented by UGS quantity and distribution, building distribution, as well as terrain, providing recommendations for each UGS with different types and sizes of stormwater facilities. (3) With the features of spatial parameter evaluation, the framework is feasible to adjust relevant thresholds and include more parameters to respond to specific project needs. (4) By quantifying the two different requirements for UGS and comparing them, any UGS with high usage conflicts can be easily identified. By evaluating all proposed criteria for UGSs in the 3D model, designers can conveniently observe simulation and adjust design scenarios to address identified usage conflicts. Thus, the proposed evaluation framework in this thesis would be valuable in effectively supporting further multi-objective UGS design

    Maximizing Green Infrastructure in a Philadelphia Neighborhood

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    Watts Branch Resiliency Master Plan

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    Urban areas are major concentrations of culture, acting as centers of trade, industry, innova - tion, and daily living. Since the industrial revolution, cities have continuously developed and further concen - trated human capital. Urban areas face a multitude of challenges, from efficient transportation to resource distribution to public safety and crime prevention. To - day, the number of people who reside in cities outnum - bers the number of people who reside outside of cities, and the proportion of the population that lives in urban areas is expected to increase to nearly 70% by 2050. As this occurs, we must make sure our cities can effectively day, the number of people who reside in cities outnumbers the number of people who reside outside of cities, and the proportion of the population that lives in urban areas is expected to increase to nearly 70% by 2050. As this occurs, we must make sure our cities can effectively provide residents with the resources and services they need not just to live but to thrive. Meanwhile, climate change threatens the health and safety of all our living spaces, especially in cities. In the near future, our cities will not only have to accommodate more people, they will also have to adapt and respond to the effects of climate change in order to maintain conditions that are safe, healthy, and liveable. The effects of climate change are far-reaching. They include increased precipitation and other extreme weather events—which result in a heightened risk of flooding and the endangerment of lives and property—and the increased fragility of ecosystems and biodiversity as they also attempt to adapt to changing living conditions. Urban environments are especially vulnerable due to large amounts of impervious surfaces, which prevent rain water infiltration and absorb heat, and limited space for ecosystems that can help mitigate these effects. This project is located in the watershed of the Watts Branch, a tributary of the Anacostia River, and spans parts of both Prince George’s County, Maryland, and the District of Columbia. It crosses densely populated urban neighborhoods, some of which are home to socially and economically vulnerable populations. Some of its residents are low-income families or live in affordable housing communities. Washington, D.C. and the State of Maryland have both experienced catastrophic flooding events in the last several years, largely driven by precipitation. Flooding in the Federal Triangle has threatened not just homes and businesses but also irreplaceable national historical documents and artifacts. Similarly, catastrophic and fatal flash flooding suffered in Ellicott City, MD, in 2018, disrupted that city’s leading industry, tourism.2 These events are devastating—as they will occur more frequently as climate change continues to have greater impacts, it is thus essential to ensure that this community is protected against these impacts. One way to address multiple challenges within an urban environment is through planning and designing urban spaces to manage stormwater, provide recreation opportunities, increase biodiversity, and reduce local surface temperatures. A multifaceted process incorporates demographic information, local habitat and biodiversity considerations, and hydrology and terrain analysis to create an urban design that functions better for its residents. These designs prioritize “blue-green” infrastructure in conjunction with traditional “gray” infrastructure. Ramboll, a Danish engineering and design consulting firm, consulting for District of Columbia Department of Energy & Environment (DOEE), and in collaboration with the Army Corps of Engineers (USACE), assembled the first phases of a community resiliency masterplan for the Watts Branch catchment in 2019. Ramboll has conducted a variety of similar projects across the world. Most prominent is a flagship project in Copenhagen, Denmark, in which Ramboll created a resiliency plan to protect the city from flooding caused by significant precipitation events. Similar projects have been conducted in New York City and Singapore. Elements from these projects are used to inform this project. Continuing Ramboll’s work, we identified further areas of concern and analyzed the social and ecological dynamics of the space. With those results, we identified opportunities to improve the site and created a watershed-level masterplan focused on prioritizing areas of concern. We then designed three conceptual “pilot projects” in representative areas of the watershed to highlight the possible infrastructure solutions that could be implemented throughout the watershed. Our infrastructure solutions and pilot projects are sensitive to the ecology of Watts Branch, respectful of its culture and history, and aesthetically responsive to the needs of the space. As urban ecosystems like that of Watts Branch present a unique intersection of ecological and social needs, it is especially important that we deliberately design such spaces to be responsive to this variety of needs for both their current and future populations.Master of Landscape Architecture Master of ScienceSchool for Environment and SustainabilityUniversity of Michiganhttps://deepblue.lib.umich.edu/bitstream/2027.42/154926/3/Watts Branch Resiliency Masterplan_365.pd

    Urban Wetlands: A Review on Ecological and Cultural Values

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    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

    Urban Wetlands: A Review on Ecological and Cultural Values

    Get PDF
    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
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