scholarly journals Site Conditions, Maintenance Costs, and Plant Performance of 10 Extensive Green Roofs in the Research Triangle Area of Central North Carolina

2020 ◽  
Vol 30 (6) ◽  
pp. 761-769
Author(s):  
Julieta Trevino Sherk ◽  
Wenyan Fu ◽  
Joseph C. Neal
Keyword(s):  
North Carolina ◽  
Plant Cover ◽  
Green Roof ◽  
Green Roofs ◽  
Economic Benefits ◽  
Plant Performance ◽  
Site Conditions ◽  
Maintenance Costs ◽  
Research Triangle ◽  
Highly Correlated

Compared with traditional roofing, green roofs (GRs) have quantifiable environmental and economic benefits, yet limited research exists on GR plant survival, maintenance practices, and costs related to plant performance. The objective of this study was to assess plant cover, site conditions, and maintenance practices on 10 extensive GRs in the Research Triangle Area of North Carolina. Green roof maintenance professionals were surveyed to assess plant performance, maintenance practices, and maintenance costs. Vegetation cover on each site was characterized. Relationships among plant performance and environmental and physical site characteristics, and maintenance practices were evaluated. Survey respondents ranked weed control as the most problematic maintenance task, followed by irrigation, pruning, and debris removal. No single design or maintenance factor was highly correlated with increased plant cover. Green roof age, substrate organic matter, and modular planting methods were not correlated with greater plant cover. Results showed a trend that irrigation increased plant cover. Plants persisting on GRs included several species of stonecrop (Sedum sp.), but flame flower (Talium calycinum) and ice plant (Delosperma basuticum) were also present in high populations on at least one roof each. Green roof maintenance costs ranged from $0.13/ft2 to $3.45/ft2 per year, and were greater on sites with more weeds and frequent hand watering.

Green roof hydrologic performance and modeling: a review

2013 ◽  
Vol 69 (4) ◽  
pp. 727-738 ◽  
Author(s):  
Yanling Li ◽  
Roger W. Babcock
Keyword(s):  
Peak Flow ◽  
Green Roof ◽  
Field Measurements ◽  
Green Roofs ◽  
Economic Benefits ◽  
Design Parameters ◽  
Technical Literature ◽  
Factors Affecting ◽  
Model Soil ◽  
Runoff Volume

Green roofs reduce runoff from impervious surfaces in urban development. This paper reviews the technical literature on green roof hydrology. Laboratory experiments and field measurements have shown that green roofs can reduce stormwater runoff volume by 30 to 86%, reduce peak flow rate by 22 to 93% and delay the peak flow by 0 to 30 min and thereby decrease pollution, flooding and erosion during precipitation events. However, the effectiveness can vary substantially due to design characteristics making performance predictions difficult. Evaluation of the most recently published study findings indicates that the major factors affecting green roof hydrology are precipitation volume, precipitation dynamics, antecedent conditions, growth medium, plant species, and roof slope. This paper also evaluates the computer models commonly used to simulate hydrologic processes for green roofs, including stormwater management model, soil water atmosphere and plant, SWMS-2D, HYDRUS, and other models that are shown to be effective for predicting precipitation response and economic benefits. The review findings indicate that green roofs are effective for reduction of runoff volume and peak flow, and delay of peak flow, however, no tool or model is available to predict expected performance for any given anticipated system based on design parameters that directly affect green roof hydrology.

scholarly journals Wind drives drought responses of green roof vegetation in two substrates

2018 ◽  
Author(s):  
Arkadiusz Przybysz ◽  
Konstantin Sonkin ◽  
Arne Sæbø ◽  
Hans Martin Hanslin ◽  
Keyword(s):  
Biological Diversity ◽  
Green Roof ◽  
Green Roofs ◽  
Plant Performance ◽  
Succulent Plant ◽  
Hieracium Pilosella ◽  
Key Factor ◽  
Substrate Moisture ◽  
Species Specific ◽  
Functional And Phylogenetic Diversity

The multifunctionality and delivery of ecosystem services from green roofs is improved by biological diversity of the roof vegetation. However, the frequency and intensity of drought episodes on extensive green roofs may limit the use of non-succulent species and the potential functional and phylogenetic diversity of the vegetation. Wind accelerates water use by plants and desiccation of the green roof substrate, and may be a key factor in selection of non-succulent plant species for green roofs. In this study, we tested wind interactions with green roof substrate composition and the effects on plant and substrate water balance, overall plant performance, and wilting and survival of three non-succulent species (Plantago maritima L., Hieracium pilosella L., and Festuca rubra L.) under realistic prolonged water deficit conditions. We found that, regardless of species or substrate tested, wind accelerated drought response. Drought-stressed plants exposed to wind wilted and died earlier, mostly due to more rapid desiccation of the growth substrate (critical substrate moisture content was 6-8%). The moderate wind levels applied did not affect plant performance when not combined with drought. Species with contrasting growth forms showed similar responses to treatments, but there were some species-specific responses. This highlights the importance of including wind to increase realism when evaluating drought exposure in non-succulent green roof vegetation.

scholarly journals Surface temperature analysis of conventional roof and different use forms of the green roof

2019 ◽  
Vol 28 (4) ◽  
pp. 632-640
Author(s):  
Anna Baryła ◽  
Agnieszka Bus ◽  
Agnieszka Karczmarczyk ◽  
Joanna Witkowska-Dobrev
Keyword(s):  
Green Infrastructure ◽  
Urban Areas ◽  
Imaging System ◽  
Plant Cover ◽  
Effective Means ◽  
Green Roof ◽  
Green Roofs ◽  
Temperature Changes ◽  
Urban Heat ◽  
Thermal Imaging System

Increasing urban populations raises a number of problems and risks that are strengthened by observed and projected climate change. An increase in green areas (so-called green infrastructure) has turned out to be an effective means of lowering temperature in the city. Green roofs can be one of the possible measures leading to achieving this aim. The aim of the study was the analysis of temperature changes of different roof surfaces (conventional roof, board, intensive roof substrate without plant cover, substrate covered with plants (shrubs). Studies on comparing the temperature between a conventional roof and green roofs were carried out in the period from April to September 2015 on the roof of the building of the Faculty of Modern Languages, University of Warsaw. The measurement was performed using the FLIR SC620 thermal imaging system. As a result of the tests, it was found that in the summer months the differences between the temperature of the green roof and the conventional roof amounted to a maximum of 31.3°C. The obtained results showed that the roof with vegetation can signifi cantly contribute to the mitigation of the urban heat island phenomenon in urban areas during summer periods.

scholarly journals Physical Characteristics of and Seed Germination in Commercial Green Roof Substrates

2015 ◽  
Vol 25 (2) ◽  
pp. 221-227 ◽  
Author(s):  
Derald A. Harp ◽  
Cheng Chen ◽  
Curtis Jones
Keyword(s):  
Seed Germination ◽  
Block Design ◽  
Green Roof ◽  
Chemical Properties ◽  
Green Roofs ◽  
Economic Benefits ◽  
Physical Characteristics ◽  
Internal Cooling ◽  
Pinto Bean ◽  
Expanded Shale

Green roofs provide multiple environmental and economic benefits, such as roof surface temperature reduction, reduced internal cooling needs, storm water management, and extended life span of roofing materials. However, green roof substrates must be relatively lightweight, so it is typically coarse with limited water holding capacity. We hypothesize the physical characteristics that make the substrates successful on a roof are likely to reduce seed germination. For this study, we tested the germination of three perennial species and one annual: shasta daisy (Leucanthemum ×superbum), yarrow (Achillea millefolium), and indian blanket (Gaillardia pulchella), and pinto bean (Phaseolus vulgaris) (as a control) across five different substrates: peat/perlite/large expanded shale, compost/sand/expanded shale, compost/black dirt/expanded shale, compost/expanded shale, and peat/perlite (control). Substrate physical and chemical properties were analyzed, and a germination test conducted using a randomized complete block design, with each species/substrate combination appearing once per block. Germination was defined as seedling emergence, and monitored every 7 days for 28 days. Pinto bean had the highest germination (76.2%) across all substrates, compared with 43.4% for indian blanket, 40.4% for yarrow, and 23.0% for shasta daisy. Seed germination, across all species, was lower in green roof substrates. Germination success was very strongly correlated with seed length, seed width, and seed area, while no relationship was found between seed germination and substrate pH or electrical conductivity (EC). Therefore, it is likely that the physical characteristics of green roof substrates create poor conditions for seed germination.

scholarly journals Substrate Depth Influences Sedum Plant Community on a Green Roof

HortScience ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 401-407 ◽  
Author(s):  
Kristin L. Getter ◽  
D. Bradley Rowe
Keyword(s):  
Plant Community ◽  
Plant Stress ◽  
Green Roof ◽  
Green Roofs ◽  
Plant Performance ◽  
Blue Spruce ◽  
Waterproofing Membrane ◽  
Substrate Moisture ◽  
Substrate Depth

Because the waterproofing membrane beneath green roofs is estimated to last at least 45 years, long-term plant performance beyond initial establishment is critical. Plants that survive initially on a green roof may not exist in the long term because of variability in climate and other factors. This study evaluated the effect of green roof substrate depth on substrate moisture, plant stress as measured by chlorophyll fluorescence, and plant community development and survival of 12 Sedum species over 4 years in a midwestern U.S. climate during 4 years of growth. Plugs of 12 species of Sedum were planted on 8 June 2005 and evaluated biweekly for absolute cover (AC). Most species exhibited greater growth and coverage at a substrate depth of 7.0 cm and 10.0 cm relative to 4.0 cm. For the species evaluated, substrate depths of at least 7.0 cm are highly recommended. AC of Sedum was significantly greater at this substrate depth than at 4.0 cm. Mean volumetric moisture content of the three substrate depths followed the same pattern as AC. When averaged over time, the 4.0-cm substrate depth held less moisture than depths of 7.0 or 10.0 cm, whereas the 7.0- and 10.0-cm substrate depths were statistically the same. Species exhibiting the greatest AC at all substrate depths were S. floriferum, S. sexangulare, S. spurium ‘John Creech’, and S. stefco. In general, species that are less suitable at these substrate depths are S. ‘Angelina’, S. cauticola ‘Lidakense’, S. ewersii, S. ochroleucum, and S. reflexum ‘Blue Spruce’.

Research of Extensive Green Roof (Spring) for Create Comfortable Environment in Taiwan City

2015 ◽  
Vol 749 ◽  
pp. 420-424
Author(s):  
Chiou Chuan Chen
Keyword(s):  
Energy Saving ◽  
Air Conditioning ◽  
Room Temperature ◽  
Green Roof ◽  
Electricity Consumption ◽  
Green Roofs ◽  
Economic Benefits ◽  
Control Area ◽  
Building Roof ◽  
Extensive Green Roof

March to May at noon control area (exposed roof) temperature of 37.56°C, test below (green roofs) surface only 24.69°C, 24.79°C room temperature on the second floor, planting mean temperature of 27.6°C, effectively prevent the roof surface temperature rise, and thus reduce the interior roof of the second temperature 12.77°C . Building extensive green roofs to cooling, mainly to reduce the building room temperature of 3.76°C;reducing air conditioning electricity consumption , accomplish cooling and energy-saving benefits.March to May at noon (12:00-13:00), ANOVA analysis of cooling efficiency, the temperature difference between the building control area as the dependent variable, compare independent variables, and found that different monitoring areas of solar radiation cooling effect,2 floor indoor cooling temperature 13.9083°C, efficiency the most significant.Roofs of buildings spring will be applied as extensive green roof in spring, creating building roof thermal comfort (24.88°C) and Auliciems (1981) estimate room comfort temperature (24.55°C) are similar, significant benefits to achieve room thermal comfort.Buildings is applied for green roofs in the spring can reduce home power consumption (reducing air conditioning systems use frequency), to energy-saving (58.17%) of the economic benefits.

Study on Landscape Design of Roof Garden

2013 ◽  
Vol 838-841 ◽  
pp. 2993-2996
Author(s):  
Ying Sun ◽  
Guang Lin Gao
Keyword(s):  
Green Roof ◽  
Complex Form ◽  
Green Roofs ◽  
Economic Benefits ◽  
Landscape Design ◽  
Garden Design ◽  
Performance Arts ◽  
And Performance ◽  
Roof Design ◽  
Roof Garden

The roof garden is a complex form of roofs landscape. Advanced green roof design played a huge ecological and economic benefits gradually being recognized for the significance of green roofs and classification, this paper study the roof garden design principles and key technologies for preliminary summary and discussion, proposed green roof functioning and performance arts beautiful landscape design methods.

INVESTIGATING THE ENVIRONMENTAL IMPACTS OF GREEN ROOF INSTALLATION

2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Amir Mahdiyar ◽  
Arham Abdullah ◽  
Sanaz Tabatabaee ◽  
Leily Mahdiyar ◽  
Saeed Reza Mohandes
Keyword(s):  
Urban Areas ◽  
Green Roof ◽  
Environmental Issues ◽  
Green Roofs ◽  
Developed Countries ◽  
Economic Benefits ◽  
Environmental Benefits ◽  
Adverse Impacts ◽  
Increasing Trend ◽  
Rural Places

Green roof installation has been used as a sustainable approach for many years in order to reduce the adverse impacts of environmental issues all around the world. These environmental issues include: global warming, air pollution, flood, carbon footprint and so on. Green roofs are practical as a sustainable approach, especially in developed countries; however, there is an increasing trend of implementing green roofs in developing countries. This paper is reviewing the benefits of green roof installation and how green roof might contribute to reduce the negative environmental issues. The environmental problems that can be solved or reduced by these benefits are discussed separately in this paper. It is concluded that due to the environmental benefits of green roof installation, it leads to many economic benefits. Moreover, green roof implementation is beneficial in both urban areas and rural places.

scholarly journals Life cycle benefits and challenges of large – scale green roof implementation in a mediterranean compact city: the case of Thessaloniki

2021 ◽  
Vol 899 (1) ◽  
pp. 012010
Author(s):  
E Koroxenidis ◽  
T Theodosiou
Keyword(s):  
Life Cycle ◽  
Green Infrastructure ◽  
Urban Areas ◽  
Large Scale ◽  
Energy Savings ◽  
Green Roof ◽  
Green Roofs ◽  
Economic Benefits ◽  
Economic Life ◽  
Waste Production

Abstract Green roof installation is considered to be an effective practice in restoring green spaces to high – density urban areas, in an effort to mitigate environmental problems that arise from their growing expansion. The present study attempts to further investigate this claim by assessing the environmental and economic life cycle benefits and challenges of two extensive green roof large – scale implementation scenarios (on existing or on well – insulated roofs) in the compact mediterranean city of Thessaloniki, Greece. In both scenarios green roofs provided energy savings (13-19%), greenhouse gas emissions (22-29%) and waste production (57-60%) reductions but also led to a significant increase in water consumption (279-291%), with performance being better in the latter case. They also accrued significant public economic benefits in both a low and high discount rate scenario, although they were not an efficient choice for private owners in the second one. These results seem to imply that green roofs could potentially be a viable urban green infrastructure solution, if their water use is minimized in a sustainable way and additional state incentives are considered.

The ecosystem service benefits of green-roof as a part of smart ecosystem-based management: A case study in Dublin, Ireland

2021 ◽  
Author(s):  
Srikanta Sannigrahi ◽  
Bidroha Basu ◽  
Arunima Sarkar Basu ◽  
Francesco Pilla
Keyword(s):  
Ecosystem Service ◽  
Green Roof ◽  
Green Roofs ◽  
Well Being ◽  
Environmental Problems ◽  
Economic Benefits ◽  
Water Infiltration ◽  
Water Runoff ◽  
Ecosystem Based Management ◽  
Extreme Precipitation Events

<p>The concept of Ecosystem-Based Management (EBM) as part of Nature-Based Solutions (NBS) have frequently been adopted in different strategic planning as a cross-sectoral mechanism to manage environmental problems. The EBM combines all relevant approaches, methods, tools, and software that collectively provide key scientific and socioeconomic evidence and eventually address environmental issues more sustainably. The specific application of EBM in different environmental problems, including flooding, have been proven effective in many cases. This ensures the superiority of EBM approaches for designing collaborative programs for solving environmental problems. The EBM offers a variety of sustainable interventions such as reducing impervious surface through porous paving, green parking lots, brownfield restoration, and deployment of green-roofs, which collectively attenuates water runoff and peak discharge, and offers protection against extreme precipitation events by enhancing water infiltration. In addition to the targeted benefits and cost-effectiveness of EBM, the supply of potential ecosystem service co-benefits that usually comes with EBM can contribute substantially to generating environmental benefits and adds community well-being. In order to analyse the superior effects of green-roof as a part of a smart-EBM framework, which has been deployed in CHQ building in Dublin, Ireland, a conceptual upscaling scenario framework has been formulated for measuring the city scale impact of green-roofs in providing multiple-valued ecosystem services. The biophysical and economic benefits of smart green-roof EBM will be estimated using varied ecosystem service modelling and standard cost-benefit analysis. The proposed smart green-roof framework is expected to have a more significant impact in minimising the flooding problems in Dublin city and expected to provide multiple regulating, supporting provisioning, and cultural benefits that can collectively surpass the deployment cost of green-roofs in the long run.</p>

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