Academic literature on the topic 'Green roofs (Gardening) – Economic aspects'

Green roofs incorporate vegetation into urban environments (specifically buildings), making it possible to replace the plant material that is destroyed during construction processes. Purpose: this study aims to identify the factors that drive the adoption of green roofs in horizontal property by means of a technology acceptance model. Materials and methods. A qualitative methodology is used, and semi-structured interviews are conducted with the community, construction companies, and employees of the Municipality of Sabaneta (Antioquia, Colombia). Findings. According to the results of this study, landscaping, temperature, energy, economic aspects, and quality of life are found to be the factors that determine the adoption of such technology. Conclusion. Therefore, green roofs become a multipurpose strategy that, besides helping to reduce the temperatures of buildings and improving air quality and harmony in landscapes, can also be used as gardens, as stated by some of the study’s participants.

Abstract The impact of urban development on the natural environment creates unique challenges for architects and the need to seek a change in design strategies by building green and sustainable buildings. Designing and displaying green elements such as roofs and walls becomes an important element in this sense. Greenery plays a very crucial role in the city space. Green roofs and walls are the missing link between the built environment and the natural environment. They can complement urban greenery. This paper aims to show the possibilities of green roofs and walls solutions in the city, their aspects and impact on the environment and people. The research method is based on the analysis of selected existing objects with greenery solutions and showing their role in creating a sustainable city. The analysis shows that the green roofs and walls offers many environmental, social and economic benefits. They have the ability to improve the microclimate and increase air humidity. Thus, they affect the health and well-being of the city's inhabitants. This technology should be considered a valuable part of the design process to tackle climate change and the energy crisis. Green roofs and facades are passive techniques and provide benefits in reducing the energy requirements of buildings, among other things, but also play a role in shaping a better visual aspect of the city. In the 21st century, people are slowly beginning to realize the advantages of green architecture, which is considered a new perspective also for the urban heat island problem. Thus, the living roofs and walls are of major importance as part of a sustainable strategy for the urban environment. Sustainable cities will exist when society makes an informed choice to move towards a more sustainable lifestyle. The green roofs and walls these are the solution for the future, for better quality of life.

Purpose – The key aspects that built environment professionals need to consider when evaluating roofs for the purpose of green roof retrofit and also when assessing green roofs for technical due diligence purposes are outlined. Although green or sod roofs have been built over many centuries, contemporary roofs adopt new approaches and technologies. The paper aims to discuss these issues. Design/methodology/approach – A mixed methods design based on a systematic review of relevant literature from parallel disciplines was used to identify and quantify the social, economic and environmental benefits of retrofitted green roofs in commercial districts. The technical issues of concern were drawn from a desk-top survey of literature and from stakeholder focus groups undertaken in Sydney in 2012. Findings – There are perceptions amongst built environmental practitioners that may act as artificial barriers to uptake. There is little direct experience within built environment professionals and practitioners, along with a fear of the unknown and a risk averse attitude towards perceived innovation which predicates against green roof retrofit. Furthermore projects with green roofs at inception and early design stage are often “value engineered” out of the design as time progresses. There is a need for best practice guidance notes for practitioners to follow when appraising roofs for retrofit and also for technical due diligence purposes. Research limitations/implications – The focus groups are limited to Sydney-based practitioners. Although many of these practitioners have international experience, few had experience of green roofs. A limited number of roof typologies were considered in this research and some regions and countries may adopt different construction practices. Practical implications – In central business districts the installation of green roof technology is seen as one of the main contributors to water sensitive urban design (WSUD). It is likely that more green roofs will be constructed over time and practitioners need knowledge of the technology as well as the ability to provide best advice to clients. Originality/value – The benefits of green roofs as part of WSUD are increasingly being recognised in terms of reduced flood risk, reduced cost of drainage, improved water quality and lower energy use, as well as other less tangible aspects such as aesthetics and amenity. This research highlights the lack of understanding of the short- and long-term benefits, a poor appreciation and awareness of these benefits; a lack of technical knowledge and issues to be considered with regard to green roofs on behalf of practitioners. The study has highlighted the need for specific training and up-skilling in these areas to provide surveyors with the technical expertise needed. There is also a need to consider how the emerging retrofit and adaptation themes are best designed into the curriculum at both undergraduate and postgraduate levels. Clearly, if the potential benefits of green roofs are to be realised in the future, building professionals need to be fully conversant with the technology and be able to provide reliable and accurate advice.

В статті розглядається потенціал садів на дахах в озелененні надмірно щільнозабудованих міст. Метою даної статті є визначити позитивні впливи та альтернативи, що може принести в Україну більш активне використання такої технології, оскільки сучасний екологічний стан міст в Україні є незадовільним. Опрацьовано низку українських та закордонних джерел, що розглядають дану проблему. Для створення уяви про те, як відбувався розвиток в сфері озеленення покрівель було вивчено історію виникнення зелених дахів, а також проаналізовано всесвітньо відомі приклади таких архітектурних рішень. Зокрема сади Семираміди, офісну будівлю Acros Fukuoka, пасивний будинок The Muse, ферми Brooklyn Grange. Виявлено, що зелені дахи можуть слугувати не лише як місця для дозвілля міського гаселення і використовуватися як території громадського простору, а й бути місцем для альтернативного влаштування рослинних ферм.З’ясовано, що введення зелених дахів в експлуатацію має високий енергоефективний вплив, що може допомогти економити та покращити управління стічними водами, краще регулювати температури будівель, зменшити вплив міських островів тепла та збільшити території середовищ існування міської дикої природи. В джерелах розглядають два основні типи озеленення покрівель: інтенсивне і екстенсивне озеленення. Вони відрізняються способом влаштування і вимогами у підтримуюючому догляді, проте в обох випадках важливими є правильне влаштування покрівель і підбір рослин. Лише врахувавши всі умови і нюанси, дотримавшись технологій влаштування можна досягти очікуваного результату.Встановлено, що озеленення дахів є важливою складовою у забезпеченні сталості цілісного розвитку в будівництві, масове використання такого способу озеленення може забезпечити не лише естетичні потреби, а й економічні. Враховуючи досвід інших країн існує потреба у введені обовязкового озеленення покріель новобудов на законодавчому рівні. This article explores the potential of green gardens in greening over-dense cities. The purpose of this article was to determine the positive influences and alternatives that a more active use of this technology can bring to Ukraine, since the current ecological state of cities is unsatisfactory. A few Ukrainian and foreign sources dealing with this problem were processed.To create an idea of how the development in the field of green roofing took place, the history of the emergence of green roofs was studied, as well as world-famous examples of such architectural solutions were analyzed. It has been found that green roofs can serve not only as recreational spaces for urban settlements and public spaces, but also as a place for alternative farms.The introduction of green roofs have high energy efficiency impacts that can improve waste water systems, better regulate building temperatures, help to reduce the impact of urban heat islands, and increase urban wildlife habitat. The sources consider two main types of roof gardening: intensive and extensive gardening. They differ in the way they are set up and the requirements for supportive care, but in both cases, the correct roofing and the selection of plants are important. Only considering of all conditions and nuances, adhering to the technology of the installations, it is possible to achieve the expected result.It has been established that roof greening is an important component in ensuring the sustainability of integral development in construction. The massive use of such a greening method can provide not only aesthetic needs, but also economic ones. Considering the experience of other countries, it is necessary at the legislative level to introduce compulsory greening of roofs in new buildings roofs in new buildings at the legislative level.Thus, modern urban planning in Ukraine requires the introduction of such «green oases» according to the level of urbanization of the environment and to the increasing of the negative anthropogenic impact. Thanks to the use of such technologies, it is possible to create a more homogeneous and sustainable ecological environment. In Ukraine, this method of landscaping is only gaining momentum, and, in the future, it is possible to greening many buildings in od to this technology. In the world, the directions of future research are the study of all the beneficial functions of green roofs, as well as solutions for individual functional areas.

Rainwater harvesting to irrigate small-scale gardens enhances food self-sufficiency to overcome rural poverty. So far rainwater harvesting is not encouraged by the Namibian National Water Supply and Sanitation Policy nor supported financially by the Namibian government. This study proposes two rainwater harvesting facilities to irrigate gardens; one collects rain from household roofs with tank storage, the second collects rain on a pond roof with pond storage. The aim of this paper is to assess the benefits of rainwater harvesting-based gardening and to propose policy and financing implications for the Namibian government. We investigate the benefits of rainwater harvesting through a literature review, a cost–benefit analysis, monitoring of project pilot plants and a comparison with the existing irrigation and drinking water infrastructure. The results indicate that rainwater harvesting offers numerous benefits in technological, economic, environmental and social terms. The facilities have a positive net present value under favourable circumstances. However, material investment costs pose a financing problem. We recommend that government fund the rainwater harvesting infrastructure and finance privately garden and operation and maintenance costs. Integrating these aspects into a national rainwater harvesting policy would create the conditions to achieve the benefits of an up-scale of rainwater harvesting based gardening in Namibia.

In recent years, the interest in "green" solutions and in particular towards the use of green roofs and walls in an urban environment, not only for the reduction of the heat flow through the roofing due to the absorption of solar radiation and to its thermal inertia, but also for the mitigation of the heat island effect linked to the evapo-transpiration processes of plants. The benefits concerning comfort, and consequently the reduction of energy and economic costs, linked to the lower energy consumption for air conditioning under these green coverings, and the improvement of the quality of living in urban areas with a wider availability of green areas, which are often usable, are undeniable aspects of a "green" design and are widely investigated and documented. Only recently, however, research has started to address the issue of green design in terms of impacts in the life cycle, calculated according to the Life Cycle Assessment (LCA) methodology. In this research two equivalent coverings are compared in terms of summer thermal performance in the Mediterranean area: an extensive green roof and a ‘high-permeation' tiles roof covering, compiling the environmental performance of the life cycle with the phases of production, use and end of life, based on Environmental Product Declaration (EPD) compliant to the EN15804 standard.

Vertical Green Structures (VGS) emerged as a building skin Nature-based Solution (NbS) aside from green roofs. The motivation underlying this VGS exploitation is fast urbanisation and the need to limit both land consumption and vegetation loss. These structures can provide several ecosystem services like air purification, biodiversity enhancement, and noise reduction. Although the usage of VGS offers different versatile and multi-scalar benefits in the built environment, they still need to respond to all the requirements of social, economic, and environmental sustainability. Over the last decades, technologies of VGS have been developed and new product types have become available in the market. This paper presents the overall development and benefits of VGS, and aims to provide a taxonomy by considering a systematic and interdisciplinary approach. The current market overview analyses and compares different aspects (i.e., environmental and economic features) of the products for a better understanding of the current state-of-the-art—from single component to system scale. The findings of this review lead to some suggestions to enhance the level of sustainability and increase the potential benefits. They look at both research and practice requirements to orient the users in selecting the most optimal VGS solution available in the market.

The utilization of green open space (RTH) in Desa Lambang Sari I, II, III, Kecamatan Lirik Kabupaten Indragiri Hulu used for ordinary services, such as gardening, exercising, and interacting, aims to determine its utilization based on activity types, the actor, vegetation types, utilization time, and its contributions on socio-cultural, economic, and environmental aspects, as well as to build collaboration between the community and the government to create an integrated RTH. The methods applied to achieve these goals included (a) Identifying the existing conditions of public RTH to determine its form, type, and function, (b) identifying the RTH utilization patterns including its types, implementation time, actors and forms of management, frequency of utilization, benefits of activity implementation and, (c) identifying the role of the community in the public RTH utilization, and (d) formulating the development of RTH needed by Desa Lambang Sari I, II, III. In the end, a development master plan was created based on the needs of the community, which became the reference for the development of this green open space.

Nowadays, with the rapid development of urbanization, the traditional agricultural production and development mode has long been unable to meet people's needs for all aspects of agriculture. Compared with the traditional agriculture in the past, modern agriculture is an expression of the latest development form of agriculture. And urban horticulture, as an important part of modern agriculture, is produced with the rapid development of urbanization and industrial modernization, and is an inevitable product of the development of social and economic level to a certain height. Especially with the increasing pressure of work and life in the city, the citizens need more and more important for green and leisure, and the role of urban gardening in urban life is more and more obvious. In this context, this paper will combine urban horticulture with the development theory of modern agriculture, facilities production technology and industrialization management mode as a background. Based on the connotation of urban horticulture, combined with examples, we analyze the development mode and characteristics of urban horticulture, and actively explore the development prospects and countermeasures of urban horticulture in the future.

Sustainable stormwater management approaches in accordance with the EU Water Framework Directive (WFD) allow a source control to handle the quality and quantity of the runoff at local level or near the source. The most popular technologies applied in Europe are green roofs, porous pavements, retention basins and bioswales/raingardens. In this article, two of these solutions (retention tank with reuse, and rain garden, respectively), applied to single dwelling case studies in a suburban area in the Silesia Region (Poland), are illustrated and analyzed. The selected cases consider technical and economic aspects as the most important factors for decision on the selection of onsite stormwater management approach. Both systems have been operational for approximately two years. The retention tank proved a good solution, reducing stormwater overflows and allowing local water reuse for lawn irrigation; however, investment and maintenance costs in this case are relatively higher. The raingarden proved to work efficiently in this small scale implementation and implied much lower initial investment and costs. The economic sustainability of these interventions at single dwelling scale was analyzed, showing interesting returns, with outcome depending on the degree of possible water reuse (lower water bills) and availability of fiscal or fee incentives. Introduction of financial incentive schemes will encourage homeowners and developers to implement stormwater control solutions, allowing rapid amortization of investment costs with additional benefits to the community, such as reduced environmental impact of stormwater overflows and possible economies in the construction and management of stormwater systems.

With the growing urbanized population, cities have become a major contributor to global energy consumption and greenhouse gas (GHG) emission. The urbanization processes also cause local climate change through excessive anthropogenic heat emission and modification of the land biophysical properties. The resultant urban heat island (UHI) effects and aggravating human heat stress have become key environmental issues in city management. Cities can be designed to be climate-conscious and energy-efficient not only to contribute to urban sustainability, but also address global climate-change issues at the local level. Green roof presents a feasible strategy for climate-conscious urban design (CCUD). With the notable thermal effects in microclimate amelioration and energy conservation, it has great potential to help cities tackle local and global climate issues. Understanding the status and underlying mechanism of green-roof thermal effects can inform optimal design and management, and provide scientific basis to promote green-roof application. This study formulates a multidisciplinary framework to assess green-roof thermal effects at building, neighborhood and district scales, based on a case study in Hong Kong. Firstly, the building-scale field measurement found that the 484 m^2 experimental extensive green roof can significantly ameliorate rooftop microclimate and cut building energy consumption. The peak surface and air temperature can be reduced by 11℃ and 4.5℃ on sunny summer days, and 7.2℃ and 2.3℃ on cloudy days, leading to an electrical energy saving of 2.80×〖10〗^4 kWh for a summer of air conditioning. The thermal performance was sensitive to background environmental factors. Solar radiation and relative humidity governs the seasonal and diurnal variation of air and surface temperatures reduction. Substrate moisture can significantly regulate the subsurface temperature but has limited effect on evapotranspiration (ET). Based on correlation and scenario analyses, this study has formulated an irrigation scheme which could balance between plant growth, thermal performance and water efficiency to achieve sustainable management of tropical extensive green roofs. Secondly, the neighborhood-scale modeling revealed that greening all roofs in residential communities can extend the cooling effects from the rooftop to the entire neighborhood. Urban design factors such as building height, distance, site coverage and orientation can affect the diurnal, horizontal and vertical pattern of the “cool-islands” created by green roofs. Green roof can also enhance the rooftop thermal comfort by alleviating the intensity and duration of heat stress. The findings suggest that compact cities can green the roof and podium space to provide thermally comfortable and recreational venues for urban residents. Thirdly, the district-scale cost-benefit analysis found that large-scale construction of green-roof infrastructure in Hong Kong can be well justified by its thermal benefits. The extensive green roof has an annual monetary benefit of HK$0.9–1.7 billion, and the intensive, HK$1.4–2.6 billion, in terms of energy saving, CO2 and air pollutant reduction. The life-cycle benefit-cost ratio (BCA) is 3.7–7 for extensive green roof, and 1.4–2.7 for the intensive, indicating the high cost-effectiveness of both types, with the extensive being more economically attractive than the intensive.
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Geography
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Doctor of Philosophy

This study examines the relationship between environmental sustainability and green schools, seeking to highlight the benefits and determine the Net Present Value (NPV) installing vegetative roofs on all schools in the Atlanta Public Schools District. This study quantifies the costs and benefits of thin-layer, or extensive, green roof systems as they compare to typical flat roofs on Atlanta Public Schools. Quantifiable benefits are detailed and suggestions are made to create the means by which other social benefits may be quantified. The purpose of this thesis is to establish proof to the Atlanta Public Schools District that over a 40 year period there are more benefits associated with installing vegetative roofs on all of their flat roofs than there are costs. While some may argue that greens roof are more costly than traditional roof systems, this study provides evidence that the cumulative benefits over a 40 year life cycle associated with large scale green roof installations, such as on all Atlanta Public Schools, are greater than the initial costs incurred. Factors included in the analysis of benefits were reductions to energy/utility costs, reduced emissions, and avoided best management practices (BMPs). Other considerations include social benefits resulting from the mitigation of storm water runoff, reductions to the urban heat island, productivity level increases (students and teachers), and avoided regulatory fees.

This study presents the results of a modeling effort to explore the role that sustainable roofing technologies play in impacting the rooftop energy balance, and the resultant net sensible heat flux into the urban atmosphere with a focus on the summertime urban heat island. The model has been validated using data from a field experiment. Roofing technologies explored include control dark membrane roof, a highly reflective (cool) roof, a vegetated green roof, and photovoltaic panels elevated above various base roofs. Energy balance models were developed, validated with experimental measurements, and then used to estimate sensible fluxes in cities located in six climate zones across the US. To evaluate the impact on urban air temperatures, a mesoscale meteorological model was used. Sensible flux profiles calculated using a surface energy balance were used as inputs to the mesoscale model. Results for a 2-day period in Portland, OR are analyzed. Average findings indicate that the black roof and black roof with PV have the highest peak daily sensible flux to the environment, ranging from 331 to 405 W/m2. The addition of PV panels to a black roof had a negligible effect on the peak flux, but decreased the total flux by an average of 11%. Replacing a black roof with a white or green roof resulted in a substantial decrease in the total sensible flux. Results indicate that if a black membrane roof is replaced by a PV covered white or a PV covered green roof the corresponding reduction in total sensible flux is on the order of 50%. Mesoscale modeling results indicate peak daytime temperature reduction of approximately 1°C for both white and green roofs. However, there is a nighttime penalty on the order of 0.75°C for the green roof case, which has been attributed to the additional thermal storage of a green roof. Findings also reveal that the addition of PV panels to a roof has a nighttime cooling effect. This is most pronounced on a white roof, with magnitudes of 1°C. The methodology developed for this analysis provides a foundation for evaluating the relative impacts of roof design choices on the urban climate and should prove useful in guiding urban heat island mitigation efforts.

As the numbers of installed greenroofs continue to grow internationally, designing greenroof growing media to reduce the amount of nutrients in the stormwater runoff is becoming essential. Biochar, a carbon-net-negative soil amendment, has been promoted for its ability to retain nutrients in soils and increase soil fertility. This study evaluated the effect on water quality of greenroof runoff after adding biochar to a typical extensive greenroof soil. Prototype greenroof trays with and without 7% biochar (by weight) were planted with sedum or ryegrass, with barren soil trays for controls. The greenroof trays were subjected to two sequential 2.9 in/hr rainfall events using a rainfall simulator. Runoff from the rainfall events was collected and evaluated for total nitrogen, total phosphorus, nitrate, phosphate, total organic carbon, and inorganic carbon. Greenroof trays containing biochar showed lower quantities of nutrients in the stormwater runoff compared to trays without biochar. Biochar-amended soil with and without plants showed a 3- to 25-fold decrease in release of nitrate and total nitrogen concentrations, as well as a decrease in phosphate and total phosphorus concentrations release into the rainfall runoff. Phosphorus results from trays planted with sedum indicate that sedum interacted with both soils to cause a decrease of phosphorus in the greenroof runoff. In correlation with a visual effect in turbidity, biochar-amended soil showed a reduction of total organic carbon in the runoff by a factor of 3 to 4 for all soil and plant trays. Inorganic carbon was similar for all tests showing that inorganic carbon neither reacted with, nor was retained by, biochar in the soil. The addition of biochar to greenroof soil is an effective way to retain nutrients in a greenroof soil, reduce future fertilizer demands, and improve the water quality of the stormwater runoff by reducing nitrogen, phosphorus, and total organic carbon concentrations in the runoff water.

Ozone in indoor environments can pose a health risk to human occupants; around half of exposure to this pollutant occurs inside buildings. One approach to reducing indoor O3 levels is to mitigate O3 as it enters a building via outdoor air ventilation supply. Often, mechanical systems that introduce outdoor air into buildings are placed on building rooftops. At the urban scale, greenery has been shown to reduce levels of some harmful pollutants, including ozone and cities like Portland, OR, are mandating green roofs be built on large commercial buildings to increase urban green surfaces. We investigate if rooftop vegetation may act as a sink for O3 as transport occurs across a green roof. It is known that O3 can react with vegetated surfaces and the ground but there is scant empirical research on said pollutant dynamics on vegetated green roofs, and little data concerning pollutant interactions occurring on other rooftop designs. Essentially unstudied is the potential of rooftop designs to affect local concentrations of pollutants where building outdoor air supply may be co-located. In this study, we investigate O3 dry deposition using resistance uptake theory in an area that includes a green roof on a local big box retail store through a field study conducted during a two-week period in the Summer of 2017. Deposition velocities and subsequently surface resistances were measured. The 10th, 50th, and 90th percentiles for resistances were 54.8 s/m, 195.3 s/m, and 3692.9 s/m respectively. A 2-D advection-diffusion model of rooftop deposition is employed to describe transport across the green roof and sensitivity analysis was performed to compare the impact of different parameters. The sensitivity analysis demonstrated that the fetch length and the vegetation height had the biggest impact, followed by the meteorological parameters; the friction velocity and heat flux. The surface resistance had the least impact on deposition. An ideal case was used to demonstrate that even when conditions are maximized for deposition, the impact on the concentration gradient is minimal at best.

Urbanization has posed great challenges for environmental sustainability, human health, and wellbeing. One of these challenges is stormwater management stemming from widespread imperviousness in urban areas. For many cities, including New York City, stormwater management issues are being exacerbated by the impacts of climate change, which is increasing the frequency and intensity of wet weather flows in multiple regions of the world. In New York City, stormwater runoff is collected with wastewater sewage in a combined sewer system (CSS) that dates back to over a century ago. At the time the system was put in place, it was designed to transport a combination of storm and wastewater to local treatment plants with a capacity of about twice the dry-weather flow. With the expansion of urbanization and population growth, this outdated system is now easily overwhelmed during wet weather flow. In some areas of the City, rainfall of less than a few millimeters can cause untreated combined storm and waste water in excess of the system’s capacity (Schlanger, 2014), to be discharged directly into a nearby surface water. The combination of storm and wastewater is referred to as combined sewerage, and overflow events are referred to as combined sewer overflows (CSOs). CSOs are a leading source of local water body pollution in NYC, as well as countless other older cities in the US and abroad that operate with combined sewer systems. To solve the CSO problem, many cities, including NYC, have adopted green infrastructure (GI) plans that aim to capture stormwater locally before it can make its way into a CSS. In New York City, right-of-way bioswales (ROWBs) are composed of about 60% of the GI that has been implemented to date (The New York City Department of Environmental Protection, 2020) for stormwater management and CSO reduction. However, despite the popularity of ROWBs as a GI intervention, few research studies have focused on quantifying their hydrological performance. This can be attributed, in part, to the greater complexity of ROWB behavior in comparison to other GI interventions, such as green roofs, which have attracted wider research interest. In addition, because ROWBs are located in the public right-of-way, monitoring and measurement of the behavior of these systems also poses additional challenges. The first study in this dissertation presents three new field methods for quantifying the stormwater retention capacity of individual ROWBs. By applying the field methods at a ROWB site located in the Bronx, NYC, the influence of rainfall characteristics and the monitored soil moisture content of the ROWB on the ROWB’s hydrological performance was explored. A definition of a so-called ‘rain peaky event’ (RPE) was introduced to divide an individual storm into several sub-events. A RPE event-based empirical model for predicting the stormwater retention behavior of the ROWB was then developed based on the monitored soil moisture content of the ROWB and the rain depth recorded every 15 minutes during a storm event. This study found that the predicted stormwater retention volume per rain depth per unit drainage area of the studied ROWB, is not significantly different from that of several NYC based extensive green roofs. However, compared to the drainage area of the green roofs, which is the same as the roof’s surface area, the drainage area of the studied ROWB was about 84 times its surface area. Thus, per unit area, the ROWB was found to have significantly higher (almost two orders of magnitude) total stormwater capacity than the extensive green roofs. The second study in this dissertation assessed the applicability of the physics-based one-dimensional finite element model HYDRUS-1D, for simulating the infiltration process of a ROWB during storm events using long-term monitored soil moisture content as an input. The simulation results from the HYDRUS-1D was validated by field measurement results taken at the ROWB site located in the Bronx, NYC, and compared with the RPE event-based empirical model presented in the first study. The HYDRUS-1D model was found capable of predicting the ROWB’s cumulative stormwater retention at intervals of one minute, as well as the total retention volume of stormwater inflows into the ROWB per rain peaky event, except for events with an average stormwater inflow intensity high than 20 cm/hr. The study revealed that HYDRUS-1D has a tendency to under-predict the retention capacity of the studied ROWB for a storm with an inflow intensity high than 20 cm/hr, thus providing a lower bound on ROWB stormwater retention. The current published version of the HYDRUS-1D was also found to be erroneous when simulating the ROWB stormwater infiltration process in cases where the ROWB’s soil moisture content was close to saturation. The third study investigated the effectiveness of increased perviousness on CSO reduction and water quality improvement in NYC, toward an aim of understanding how GI implementation can improve city-wide stormwater management issues. By using the enterococci (ENT) concentration as an indicator of water quality and the runoff coefficient to represent land perviousness over an area, a random forest classification model was developed for predicting whether a water body is swimmable or not at 50 shore sites along the main waterways of NYC. The model revealed the significant contribution of land perviousness, and hence GI interventions and green space, to CSO pollution reduction for CSO-shed areas located adjacent to slower-moving waterways. For CSO-shed areas located adjacent to faster moving waterways, the influence of land perviousness was found to be negligible. The random forest classification model developed in this third study can be used as a tool for city planners and agencies as part of plans for GI implementation that focus on the optimization of local water quality, among other objectives. Overall, the research presented in this dissertation aimed to provide a deeper insight into the factors governing the hydrological performance of the most prevalent GI in NYC – namely right-of-way bioswales. In addition, the research aimed to provide insight into linkages between land perviousness and CSO pollution levels in NYC local waterways, which can be used to inform the implementation and overall performance of the entire NYC GI system.

The conversion of natural landscapes for human use over the past century has led to significant ecological consequences. By clearing tropical forests, intensifying agriculture and expanding urban centers, human actions have transformed local, regional and global hydrology. Urban landscapes, designed and built atop impervious surfaces, inhibit the natural infiltration of rainfall into the subsurface. Deforestation, driven by the demand for natural resources and food production, alters river flow and regional climate. These land cover changes have manifested into a number of water management challenges, from the city to the watershed scale, and motivated investment into landscape re-greening programs. This movement has prompted the need for monitoring, evaluation and prediction of the hydrological benefits of re-greening. The research presented in this dissertation assesses the contribution of different re-greening strategies to water resources management, from multiple scales. Specifically, re-greening at the city scale is investigated through the study of vegetated rooftops (green roofs) in a dense urban environment. Re-greening at the watershed scale is investigated through the study of forest regeneration on deforested and ecologically degraded land in the tropics. First, the benefits of city re-greening for urban water management are investigated through monitoring and modeling the hydrological behavior of a number of green roofs in New York City (NYC). Influence of green roof size and rainfall characteristics on a green roof’s ability to retain/ detain rainwater are explored and the ability of a soil infiltration model to predict green roof hydrology is assessed. Findings from this work present insight regarding green roof design optimization, which has utility for scientific researchers, architects, and engineers. Next, a cost effective tool is developed that can be used to evaluate green roof hydrologic performance, citywide. This tool, termed the Soil Water Apportioning Method (SWAM), generates green roof runoff and evapotranspiration based on minimally measured parameters. SWAM is validated using measured runoff from three extensive green roofs in NYC. Additional to green roofs, there is potential for SWAM to be used in the hydrologic performance evaluation of other types of green infrastructure, making SWAM a relevant tool for city planners and agencies as well as for researchers from various disciplines of study. Finally, the impact of degraded landscape re-greening is investigated using a case study of 15 watersheds in Puerto Rico that have experienced extensive reforestation. The study provides evidence of improved soil conditions following reforestation, which in effect positively impacts streamflow generation processes. Findings from this work fill a gap in knowledge regarding the hydrological benefits of forest regeneration in mesoscale watersheds and provide guidance for future investment into reforestation programs. Land cover will inevitably continue to change to meet the needs of a growing and increasingly urban population. Yet there is potential to offset some of the ecological effects – especially those on hydrology – that result from land cover change. As a whole, this dissertation aims to contribute knowledge that can be used to make the re-greening of altered landscapes more realizable.

A high perceniage of vacani space within downtown Vancouver is composed of inaccessible rooftops that, through green roof implementation, are capable of sustaining a network of accessible open space that supports urban food production. With an increasing local interest in urban agriculture, an organic rooftop food production technology is due to emerge on the marketplace. This study explores the development of urban agriculture within downtown Vancouver as a potential incentive for green roof implementation. Through an analysis of current research and a related case study, a design for an organic herb garden was developed for an existing green roof above a specialty-foods grocery store in downtown Vancouver. This model allows the green roof to support the growing and selling of organic food on-site, bringing the celebration of food production to the public realm, while strengthening the connection between the green roof, its' built form and the surrounding community. The design integrates a highly-productive organic herb garden with social areas for on-site residents and employees. Using developed indicators for sustainability, a final comparative analysis of the proposed design against the related case study and existing site was completed. This study informs new directions for the social function of the green roof, while recognizing how policy and regulations for future urban development can support the advancement of urban agriculture.
Applied Science, Faculty of
Architecture and Landscape Architecture (SALA), School of
Graduate

AbstractGreen roofs are components of the building envelope that have become increasingly popular in urban contexts because other than providing numerous environmental benefits they are also capable of reducing building energy consumption, especially in summer. However, despite all these advantages, green roofs are still affected by some limitations. Specifically, there are some gaps affecting the energy modelling consisting in the absence of a proper database, information (growth stage, leaf area index, and coverage ratio) relative to the different green roof plant species, which technicians could use in case of lack of actual field data to perform energy analysis of buildings equipped with green roofs. These gaps concern also environmental and economic assessments of such technology. In fact, the currently available green roof LCA and LCC studies seem to underestimate the role of the substrate on the overall environmental impact and the role of the disposal phase on the life cycle cost of the green roof. In this chapter, all these aspects are addressed, and contributions to their solution, which arose from both experimental and modelling research, carried out by the authors are presented.

Green roof is a building envelop embedded concept to compensate the consequences of green losses due to building constructions with its numerous benefits in all environmental, economic and social aspects. But the application of green roofs in Sri Lankan buildings is seemed to be limited due to the deficiency in comprehensive awareness of the benefits of the green roof concept among construction stakeholders. Though the global studies on green roof application are widespread among different green roof types, their results do not indicate any consistency between green roof application and climate. This warrants the current study to investigate the benefits offered by green roofs in the local context. A thorough literature synthesis had initially conducted to review the green roof concept, types of green roofs, and benefits offered. Subsequently, a preliminary investigation was performed to identify the green roofs available in Sri Lanka. Thereafter, the case study strategy was adopted to evaluate the benefits of intensive and semi-intensive green roof types through interviews. The collected data were analysed using manual content analysis. Analysis revealed that both intensive and semi-intensive type offers key benefits such as energy conservation, and stormwater run-off reduction in the Sri Lankan context. In addition, the intensive type offers benefits such as carbon emission control, and absorption of urbanized noise which can be aligned with the main criteria of sustainable sites, energy & atmosphere, and indoor environment quality of green rating systems. Therefore, the study suggests that an adequate recognition to green roof implementation in the green rating systems would enhance the green roof application and thereby contribute to achieving sustainability of buildings in terms of these criteria.