scholarly journals Green Roof Design with Engineered Extensive Substrates and Native Species to Evaluate Stormwater Runoff and Plant Establishment in a Neotropical Mountain Climate

2020 ◽  
Vol 12 (16) ◽  
pp. 6534
Author(s):  
Carlos Vicente Rey ◽  
Natalia Franco ◽  
Gwendolyn Peyre ◽  
Juan Pablo Rodríguez
Keyword(s):  
Native Species ◽  
Green Roof ◽  
Oxygen Demand ◽  
Green Roofs ◽  
Environmental Benefits ◽  
Plant Establishment ◽  
Climate Conditions ◽  
Mountain Climate ◽  
Roof Design ◽  
Selection Of

Green roofs are increasingly being implemented in cities for their multiple environmental benefits. Their optimal design requires an appropriate selection of components, including substrates and plant species, to ensure local sustainability in the long term. The present study seeks to assess the runoff quality and quantity of extensive green roofs located in Bogotá (Colombia). The assessment consists of testing different substrates, designed using locally available constituents and a selection of native species. The best performing substrate mixtures, in terms of runoff volume reduction and plant establishment, were jointly evaluated with three native species (i.e., Paepalanthus alpinus, Achryrocline bogotensis and Echeveria ballsii). On average, engineered substrates presented significantly lower concentrations in several water quality parameters (electric conductivity, total phosphorus, phosphates, Total Kjeldahl Nitrogen, nitrates, nitrites, color, biological oxygen demand and chemical oxygen demand) than the commercial extensive substrate used as control. The species Paepalanthus alpinus and Echeveria ballsii showed significant establishment and were considered potentially suitable species for green roofs in Bogotá. The obtained results, therefore, provide recommendations for green roof design in neotropical mountain climate conditions.

scholarly journals Green Roof Design: State of the Art on Technology and Materials

2019 ◽  
Vol 11 (11) ◽  
pp. 3020 ◽  
Author(s):  
Stefano Cascone
Keyword(s):  
State Of The Art ◽  
Green Roof ◽  
Green Roofs ◽  
Future Research ◽  
Climate Conditions ◽  
Drainage Layers ◽  
Innovative Materials ◽  
Protection Filter ◽  
Roof Design ◽  
Selection Of

In order to consider green roofs as an environmentally friendly technology, the selection of efficient and sustainable components is extremely important. Previous review papers have mainly focused on the performance and advantages of green roofs. The objective of this paper is to examine the primary layers: The waterproof and anti-root membranes; the protection, filter, and drainage layers; the substrate; and the vegetation. First, the history, modern applications, benefits and classification are analyzed in order to present a well-defined state of the art of this technology. Then, the roles, requirements, characteristics, and materials are assessed for each green roof layers. This technology was compared to a conventional roof technology, Mediterranean climate conditions and their influence on green roof design were assessed, also comparing them with Tropical area and focusing on irrigation systems, examples about the commercial materials and products available in the market were provided and innovative materials coming from recycled sources were analyzed. Future research should evaluate new materials for green roof technologies, in order to enhance their performance and increase their sustainability. The information provided in this review paper will be useful to develop Mediterranean green roof guidelines for selecting suitable components and materials during the design and installation phases.

scholarly journals Green Roof Design Techniques to Improve Water Use under Mediterranean Conditions

Urban Science ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 14 ◽  
Author(s):  
Teresa Paço ◽  
Ricardo Cruz de Carvalho ◽  
Pedro Arsénio ◽  
Diana Martins
Keyword(s):  
Water Use ◽  
Green Roof ◽  
Green Roofs ◽  
Climatic Conditions ◽  
Native Plant ◽  
Additional Energy ◽  
Climate Conditions ◽  
Native Plant Species ◽  
Roof Design ◽  
Mediterranean Conditions

Green roof typology can vary depending on buildings structure, climate conditions, substrate, and plants used. In regions with hot and dry summers, such as the Mediterranean region, irrigation plays an essential role, as the highest temperatures occur during the driest period of the year. Irrigation might reduce the heat island effect and improve the cooling of buildings during this period, however, the added cost of maintenance operations and additional energy consumption could outrun the benefits provided by the project. Moreover, in situations where water is scarce or primarily channelled to other uses (e.g., domestic, agriculture or industry) during drought occurrence, it is advisable to implement green roof projects with the lowest use of water possible. The objective of the present work is to investigate solutions to optimize water use in green roofs under Mediterranean conditions, such as those of southern Europe. Two case studies are presented for Portugal, and potential techniques to reduce irrigation requirements in green roofs were tested. These addressed the use of native plant species, including the extreme type of a non-irrigated green roof (Biocrust roof) and techniques for plant installation. Plant drought tolerance was found to be an advantage in green roofs under these climatic conditions and, for the species studied, aesthetic value could be maintained when irrigation decreased.

scholarly journals Performance of Green Roofs for Rainwater Control

2020 ◽  
Author(s):  
A. Raimondi ◽  
G. Becciu
Keyword(s):  
Goodness Of Fit ◽  
Probabilistic Approach ◽  
Green Roof ◽  
Green Roofs ◽  
Water Retention Capacity ◽  
Retention Capacity ◽  
Climate Conditions ◽  
Average Return ◽  
Roof Design ◽  
The Given

AbstractGreen roofs can be an effective tool for sustainable urban drainage, since they reduce and retain runoff by delaying its peak. Most studies analysing the retention capacity of green roofs are usually referred to a specific place and roof condition and do not consider the possibility that the roof could be partially pre-filled from previous rainfalls at the beginning of the given event. The aim of this paper is to develop an analytical probabilistic approach to evaluate green roof performance for stormwater control in terms of runoff that could be applied for different sites and climate conditions. To this end, the possibility that the green roof retention capacity could not be completely available owing to pre-filling from previous rainfall events has been considered and equations for an optimum green roof design, relating the runoff average return interval to the water retention capacity, have been proposed. The influence of parameters affecting the runoff process has been examined in depth and a case study to test the goodness of fit of the resulting equations has been developed.

scholarly journals A laboratory study to determine the use of polluted river sediment as a substrate for extensive green roofs

2018 ◽  
Vol 78 (11) ◽  
pp. 2247-2255 ◽  
Author(s):  
Wei Zhang ◽  
Xing Zhong ◽  
Wu Che ◽  
Huichao Sun ◽  
Hailong Zhang
Keyword(s):  
River Sediment ◽  
Peat Soil ◽  
River Sediments ◽  
Green Roof ◽  
Oxygen Demand ◽  
Green Roofs ◽  
Polluted River ◽  
Artificial Rainfall ◽  
Study Laboratory ◽  
Extensive Green Roofs

Abstract In this study, laboratory-scale green (e.g. living) roof platforms were established to assess the potential use of polluted river sediment in their substrate mixture. The mean runoff retention of the green roof platforms, which contained peat and/or river sediment, after 11 artificial rainfall events was >72%, significantly higher than traditional roofs. However, green roof platforms that had been filled with peat soil showed chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) leaching. Green roofs that had used river sediment showed good leaching control for COD, TN and TP. The cumulative leaching masses from the green roofs contained 30% (COD), 42% (TN) and 47% (TP) as much as the total leaching mass from traditional roofs, and the Cu, Zn, Cd and Pb leaching risk from green roofs when river sediments are used as part of a substrate mixture was relatively low. Despite some nutrient leaching in the initial phase of runoff from the green roofs, river sediment has the potential to be used as a substrate for extensive green roofs.

scholarly journals Selecting Potential Moss Species for Green Roofs in the Mediterranean Basin

Urban Science ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 57 ◽  
Author(s):  
Ricardo Cruz de Carvalho ◽  
Zulema Varela ◽  
Teresa Afonso do Paço ◽  
Cristina Branquinho
Keyword(s):  
Climate Change ◽  
Mediterranean Basin ◽  
Vascular Plants ◽  
Green Roof ◽  
Green Roofs ◽  
Potential Candidate ◽  
Moss Species ◽  
The Mediterranean ◽  
The Mediterranean Basin ◽  
Selection Of

Green roofs are important infrastructures to address the effects of climate change in urban areas. However, most studies and applications have been done in cooler and wetter regions of the northern hemisphere. Climate change will lead to more extreme weather events, such as increased drought and decreased precipitation with intense flash rain events. Increase desertification is expected especially in the Mediterranean Basin, where in summer, radiation and temperature are high and water is scarce. Therefore, while vascular plants increase water consumption in green roofs during warmer periods, mosses present themselves as potential candidates due to their poikilohydric nature, responding to the environmental availability of water, completely drying out and recovering upon rehydration. Although criteria for the selection of vascular plants adapted to the Mediterranean and suitable for green roofs have been developed, no information is available regarding the selection of mosses based on scientific criteria. Here we propose selection criteria for moss species based on ecological preferences according to Ellenberg’s values and help to define moss traits suitable for a nonirrigated, nature-based green roof that tolerates the Mediterranean climate. The main result is a table of potential candidate mosses that can be either used as standalone or in conjunction with vascular plants to decrease water usage and/or manage stormwater through an easily applicable selection methodology. For green roof practitioners, we proposed that acrocarpous mosses exhibiting turf/cushion life forms and colonist or perennial life strategies best fit the requirements for such a green infrastructure in extreme climate regions with scarce water resources.

scholarly journals Effects of Extensive Green Roofs on Energy Performance of School Buildings in Four North American Climates

Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 6 ◽  
Author(s):  
Milad Mahmoodzadeh ◽  
Phalguni Mukhopadhyaya ◽  
Caterina Valeo
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Plant Height ◽  
Green Roof ◽  
Green Roofs ◽  
Energy Performance ◽  
Design Parameters ◽  
Soil Thickness ◽  
Area Index ◽  
Roof Design

A comprehensive parametric analysis was conducted to evaluate the influence of the green roof design parameters on the thermal or energy performance of a secondary school building in four distinctively different climate zones in North America (i.e., Toronto, ON, Canada; Vancouver, BC, Canada; Las Vegas, NV, USA and Miami, FL, USA). Soil moisture content, soil thermal properties, leaf area index, plant height, leaf albedo, thermal insulation thickness and soil thickness were used as design variables. Optimal parameters of green roofs were found to be functionally related to meteorological conditions in each city. In terms of energy savings, the results showed that the light-weight substrate had better thermal performance for the uninsulated green roof. Additionally, the recommended soil thickness and leaf area index for all four cities were 15 cm and 5 respectively. The optimal plant height for the cooling dominated climates is 30 cm and for the heating dominated cities is 10 cm. The plant albedo had the least impact on the energy consumption while it was effective in mitigating the heat island effect. Finally, unlike the cooling load, which was largely influenced by the substrate and vegetation, the heating load was considerably affected by the thermal insulation instead of green roof design parameters.

scholarly journals Modeling Green Roof Potential to Mitigate Urban Flooding in a Chinese City

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2082 ◽  
Author(s):  
Li Liu ◽  
Liwei Sun ◽  
Jie Niu ◽  
William J. Riley
Keyword(s):  
Green Roof ◽  
Water System ◽  
Green Roofs ◽  
Subtropical Climate ◽  
Urban Flooding ◽  
Climate Conditions ◽  
Roof System ◽  
Groundwater Levels ◽  
Rain Season ◽  
Peak Runoff

The Middle and Lower Reaches of the Yangtze River (MLRYR) region, which has humid subtropical climate conditions and unique plum rain season, is characterized by a simultaneous high-frequency urban flooding and reduction in groundwater levels. Retrofitting the existing buildings into green roofs is a promising approach to combat urban flooding, especially for a densely developed city. Here, the application potential of the Green Roof System (GRS) and the Improved Green Roof System (IGRS) designed to divert overflowing water from green roofs to recharge groundwater were analyzed in a densely developed city, Nanchang, China. For the first time, the influence of GRS on the hydraulic condition of Combined Sewage System/Storm Water System (CSS/SWS) is analyzed, which is a direct reflection of the effect of GRS on alleviating urban flooding. The simulation results show that GRS can retain about 41–75% of precipitation in a 2-hour timescale and the flooding volumes in the GRS/IGRS region are 82% and 28% less than those of the Traditional Roof System (TRS) in 10- and 100-yr precipitation events, respectively. In the continuous simulations, GRS also enhances Evapotranspiration (ET), which accounts for 39% of annual precipitation, so that reduces the cumulative surface runoff. Considering the IGRS can provide more hydrological benefits than the GRS under the same climate conditions, we may conclude that the widespread implementation of both the GRS and the IGRS in Nanchang and other densely developed cities in the MLRYR region could significantly reduce surface and peak runoff rates.

Simulation of Thin Green Roof for Summer in Seoul

2017 ◽  
Vol 25 (04) ◽  
pp. 1750034 ◽  
Author(s):  
K. H. Byun
Keyword(s):  
Numerical Analysis ◽  
Simple Model ◽  
Green Roof ◽  
Experimental Studies ◽  
Green Roofs ◽  
Weather Data ◽  
Climate Conditions ◽  
Four Seasons ◽  
Planning Experiment ◽  
Insulation Status

The purpose of this paper is to simulate the performance of thin green roofs during summer in Seoul, where there are four seasons. Many experimental studies are available for the green roofs, but there have not been many analytical studies. Numerical analysis is applied to a simple model developed for this study. The effects of the parameters affecting green roof performance are studied using several roof types. The weather data from Korea Meteorological Administration for the summer in Seoul have been used as an input for the simulation model. The results agree with the trends reported in previous studies. The importance of insulation status of the roof before applying green roof and the climate conditions is confirmed. Analysis such as this paper is necessary and useful before applying green roof or planning experiment on green roof.

scholarly journals Technical considerations in green roof retrofit for stormwater attenuation in the Central Business District

2015 ◽  
Vol 33 (1) ◽  
pp. 36-51 ◽  
Author(s):  
Sara Wilkinson ◽  
Jessica Lamond ◽  
David G Proverbs ◽  
Lucy Sharman ◽  
Allison Heller ◽  
...  
Keyword(s):  
Built Environment ◽  
Focus Groups ◽  
Energy Use ◽  
Relevant Literature ◽  
Green Roof ◽  
Green Roofs ◽  
Environmental Benefits ◽  
Design Stage ◽  
Due Diligence ◽  
Content Type

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.

scholarly journals Irrigation Lowers Substrate Temperature and Enhances Survival of Plants on Green Roofs in the Southeastern United States

2011 ◽  
Vol 21 (5) ◽  
pp. 586-592 ◽  
Author(s):  
Julie Guckenberger Price ◽  
Stephen A. Watts ◽  
Amy N. Wright ◽  
Robert W. Peters ◽  
Jason T. Kirby
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Green Roof ◽  
Empirical Evaluation ◽  
Green Roofs ◽  
The United States ◽  
Environmental Benefits ◽  
Plant Selection ◽  
Soil Temperatures ◽  
Cold Hardy

Green roofs are becoming increasingly prevalent in the United States due to their economical and environmental benefits as compared with conventional roofs. Plant selection for green roofs in the variable climate of the southeastern United States has not been well evaluated. Shallow substrates on green roofs provide less moderation of temperature and soil moisture than deeper soils in traditional landscapes, necessitating empirical evaluation in green roof environments to make informed recommendations for green roof plant selection. Nineteen species and cultivars, including succulents, grasses, and forbs, were evaluated under seasonal irrigated and non-irrigated conditions in experimental green roofs. Plants were planted on 26 Oct. 2009 and each evaluated for survival and increase in two-dimensional coverage of the substrate during establishment, after overwintering, and after the first growing season. The winter 2009–10 was colder than normal, and some plants, such as ice plants (Delosperma spp.), considered to be cold-hardy in this climate did not survive through the winter. Irrigation influenced survival for the summer period and only succulent plants like stonecrops (Sedum spp.) survived without irrigation. Irrigated experimental green roofs had significantly lower summer substrate temperatures (up to 20 °F lower) and plants survived in irrigated conditions. Plants that survived both winter and summer under irrigated conditions include pussytoes (Antennaria plantaginifolia), mouse-ear tickseed (Coreopsis auriculata), eastern bottlebrush grass (Elymus hystrix), glade cleft phlox (Phlox bifida stellaria), and eggleston's violet (Viola egglestonii). Irrigation is recommended on extensive green roofs to increase the palette for plant selection by protecting against plant mortality due to drought and extreme soil temperatures.

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