Green Roof

Green roofs present a viable solution for increasing rainwater retention while improving the energy performance of both new and existing buildings. Considering the widespread occurrence of existing buildings, it is worthwhile to conduct an in-depth analysis of green roof feasibility for retrofitting these buildings. In such cases, the first constraint is related to structural compatibility. Therefore, the use of lightweight systems should be prioritized to minimize overloading of the existing roof. Another possible constraint concerns the viability of green roofs. The main advantages of green roofs are their energy savings and environmental benefits. In this study, different green roof solutions were evaluated and their performance was compared against the findings of previous studies. The analysis was carried out in the Mediterranean city of Catania, and the results show that only green roof solutions with a load limit of 1.46 kN/m 2 are suitable for retrofitting existing buildings. As regards the energy savings, energy consumption for cooling was reduced by 31–35%, and during winter, energy consumption for heating decreased by 2–10%. The environmental benefits were quantified during summer and compared to those of non-vegetated roofs. The results show removals of 1.35 kg m-2 ·y −1 of CO 2 and 0.03 kg m-2 ·y −1 of NO 2. Finally, the economic analysis indicates that the discounted payback time of the investment varies from 13 to 18 years depending on the substrates and vegetation used on the green roof.

Urban growth has been fast for decades. Because money is very important in this urban-based world, humanity focuses on economic development, and is often too busy to deal with sustainability. Therefore, in a world that is constantly changing, creating sustainable cities that contain a diverse range of habitats supporting plant establishment is essential. Some surprising urban habitats in which plants can grow, such as cracks on pavements and walls, rocky areas, abandoned places and roofs might be extremely important for sustainability, while urban spaces are under artificial pressure. In this study, which suggesting a method to create more sustainable green roofs for urban areas, and considering roof vegetation is already important for supporting the ecology of urban areas, we surveyed 37 roofs in an urban part of Trabzon city focusing on the habitat effect. We found 51 plant species growing on these 37 roofs, and determined five different roof vegetation typologies in the research ...

Urban growth has been fast for decades. Because money is very important in this urban-based world, humanity focuses on economic development, and is often too busy to deal with sustainability. Therefore, in a world that is constantly changing, creating sustainable cities that contain a diverse range of habitats supporting plant establishment is essential. Some surprising urban habitats in which plants can grow, such as cracks on pavements and walls, rocky areas, abandoned places and roofs might be extremely important for sustainability, while urban spaces are under artificial pressure. In this study, which suggesting a method to create more sustainable green roofs for urban areas, and considering roof vegetation is already important for supporting the ecology of urban areas, we surveyed 37 roofs in an urban part of Trabzon city focusing on the habitat effect. We found 51 plant species growing on these 37 roofs, and determined five different roof vegetation typologies in the research ...

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Abstract According to projects and practices that the Italian botanists and ecologists are carrying out for bringing “more nature in the city”, new insights for a factual integration between ecological perspectives and more consolidated aesthetic and agronomic approaches to the sustainable planning and management of urban green areas are provided.

Roof garden can be used as natural environment in an urban setting. Rooftop agriculture with green roof systems can become an attractive possibility. The aesthetic value of green roofs is considered important in cities where roof escapes are dominated by gray color and unattractive structures. The instant objective of this research was to examine on question: What is the resident’s preference of awareness regarding urban agriculture at rooftop garden? The purpose of this study is to understand the resident’s preference of awareness regarding urban agriculture at rooftop garden. The awareness and potential of rooftop urban agriculture are examined. In this research a method presented quantitative - survey questionnaire distributed among of residents in The Heritage condominium in Selangor and Sri Putramas 2 in Kuala Lumpur. The result is expected to lead towards cognition and awareness to elevate sustainable building and promoting the usage of urban agriculture at rooftop gardening r...

Green Roofs (GRs) are increasing in popularity due to their ability to manage roof runoff while providing a number of additional ecosystem services. Improvement of hydrological models for the simulation of GRs will aid design of individual roofs as well as city scale planning that relies on the predicted impacts of widespread GR implementation. Machine learning (ML) has exploded in popularity in recent years, however there are no studies focusing on the use of ML in hydrological simulation of GRs. We focus on two types of ML-based model: long short-term memory (LSTM) and gated recurrent unit (GRU), in modelling GRs hydrological performance, with sequence input andsingle output (SISO), and synced sequence input and output (SSIO) architectures. Results of this paper indicate that both LSTM and GRU are useful tools for GR modelling. As the time window length (memory length, time step length of input data) increases, SISO appears to have a higher overall forecast accuracy. SSIO delivers the best overall performance, when the SSIO is close to, or even exceeds, the maximum window size.

One of the key measures to fight urban heat island (UHI) phenomenon is by increasing the
use of green approaches including green technologies and vegetation. However, there is a shortage
of available space for establishing greening elements due to high density of urban development and
high cost of urban land. By using green roofs, the hottest spots of a city can be mitigated. Further
advantages of green roofs include mitigating air pollution, improving management of run-off water,
improving public health and enhancing the aesthetic value of the urban environment. This paper
reviewed, analyzed, and discussed previous literature on green roofs and their role in alleviating
UHI. Previous researches acknowledged the ability of green roofs in UHI mitigation. This paper
recommends using green roofs as a main strategy for decreasing the harmful impacts of UHI
especially the high air temperatures as well as their ability to add to the greening of cities.

Arid region housing in Australia is generally
inadequately designed, southern, temperate-climate,
suburban housing with little concession to the
harsh climate. Bare desert soils are subject to
high temperatures. Plants can be used to moderate
and reduce earth temperature and modify
microclimate. Using landforming and waterconservative
irrigation methods,artificial oases,of
designed plant-communities can be established.
Settlements could be built within these plant
structures. Guidelines for earth sheltered
architecture in hot arid climates are suggested.

Berkembang penduduk bandar menyumbang yang membawa banyak masalah yang berkaitan. Jelas sekali fungsi yang penting dalam bumbung adalah untuk menjaga cuaca daripada bangunan tinggi tetapi, tidak ada bumbung perlu dikekang untuk tujuan ini tunggal, terutama dalam hal ini pembangunan bandar global yang buat adalah amat sukar untuk mencari tanah untuk taman-taman dan taman-taman dan juga kerana, penggunaan pertanian bandar. Kajian ini kami berhasrat untuk memahami subjek yang taman bumbung untuk penggunaan pertanian bandar di taman bumbung di bangunan tinggi. Kertas ini adalah kertas kajian yang cuba untuk beberapa ciri-ciri taman bumbung untuk kegunaan pertanian bandar di taman bumbung di bangunan tinggi. Akhir sekali, penggunaan pertanian bandar di taman atas bumbung adalah sangat berguna untuk penduduk yang tinggal di dalam bangunan yang mempunyai teknologi ini, sebagai contoh ia boleh membantu untuk mencapai kemampanan ekonomi dan alam sekitar. Di samping itu, dengan menggunakan pertanian bandar di taman atas bumbung yang boleh membantu negara-negara yang berbeza untuk keselamatan makanan. Jadi, manfaat taman bumbung dan pertanian bandar digalakkan untuk orang-orang yang, tinggal di bangunan tinggi untuk kegunaan taman bumbung di Malaysia.

One of the key measures to fight urban heat island (UHI) phenomenon is by increasing the use of green approaches including green technologies and vegetation. However, there is a shortage of available space for establishing greening elements due to high density of urban development and high cost of urban land. By using green roofs, the hottest spots of a city can be mitigated. Further advantages of green roofs include mitigating air pollution, improving management of run-off water, improving public health and enhancing the aesthetic value of the urban environment. This paper reviewed, analyzed, and discussed previous literature on green roofs and their role in alleviating UHI. Previous researches acknowledged the ability of green roofs in UHI mitigation. This paper recommends using green roofs as a main strategy for decreasing the harmful impacts of UHI especially the high air temperatures as well as their ability to add to the greening of cities.

Recently, thermal properties of the landscaped rooftops and walls have attracted the interest of researchers because of the potential to minimize energy consumption in urban areas and to aid summer-time thermal control. For this reason the creation of a plant-based shade for walls or above buildings is highly important. In this paper we evaluate using Lygodium japonicum, one of the many ferns and fern allies traditionally used in Japanese gardening, as a component of thermal-buffering green walls. Lygodium japonicum, the only climbing fern species in Japan, is fast-growing, adheres easily to walls and has a climbing nature. A simple thermal analysis of the sun-shading effect of Lygodium canopy suggested that local surface temperature above the ceramic tiles placed on the rooftop of a building can be buffered (lowered in daytime and maintained relatively warm at night) by the presence of leafy climbing ferns covering the tiles, possibly due to the reflection and absorbance of solar radiation. Furthermore, the presence of the plants may also slow the night-time release of heat from the building surface. Because plants installed on tall walls or on the tops of buildings are not easily accessed for manual care, we performed a real-time routine monitoring and control of plant growth status using various optical sensors that could be automated and monitored remotely for large-scale applications. For this purpose, the optical properties of a L. japonicum canopy under solar incident light have been determined. In order to evaluate the natural shading and growing properties of a green canopy, the incident solar radiation spectrum (J), leaf canopy-filtered light spectrum (transmittance, T) and leaf-reflectivity spectrum (R) were measured. By reading the reflectivity spectrum, concomitant chlorophyll fluorescence signals (F) from Lygodium leaves were also detected at 760 nm, which corresponds to the O2-A Fraunhofer line. Our data suggests that the daily change in photosynthetic status (P) can be traced by monitoring the change in relative F in relation to the estimated heat loss (H) and measured J, R, and T using a series of practical equations designed to roughly estimate the gross photosynthetic response within the plant canopy. Using our equations, the photosynthetic capacity in the plant canopy structure could be simply simulated and predictable by optical sensors.

This paper discusses the awareness of green roof technology among Malaysian professionals in built environment industry and its potential in the country’s market. A total of 30 projects of local green roofs has also been identified and used in this study. Online survey is used as the tool to get feedback from the professionals who are the professional, in the construction discipline, the landscape architect, architect, developer, government officer, urban planner, project executive and also academicians.

The ecological approaches has come up in architecture in conjunction with sustainability that has become an important concept especially in the later 20th century. In the framework of this approach, planting practices are increased on the some parts of buildings such as roof, terrace or wall. Roof-terrace gardens is seen as the way of recovering back of open and green areas to urban. There are many contributions of roof-terrace gardens for buildings and urban. The importance of roof gardens gradually increase in our country and the World. There are also economic benefits and social benefits of roof gardens that bring together nature and citizens besides physical benefits. In this study, historical development, types and benefits to buildings and urban of roof gardens are investigated as theoretical. Within the context of findings, four accommodation buildings are chosen which have flat roofs that not used as actively and situated in different location of central district of Edirne. Opportunity to use as roof garden of these buildings is analyzed and brought forward a proposal for planting. As a result, contributions of roof gardens practices to urban ecology is become a current issue effectively specific to Edirne and ecological structuring/accommodation conception is presented to urban shareholders that serve for accommodation sector by means of roof gardens practices.

ABSTRACT Roof garden can be used as natural environment in an urban setting. Rooftop agriculture with green roof systems can become an attractive possibility. The aesthetic value of green roofs is considered important in cities where roof escapes are dominated by gray color and unattractive structures. The instant objective of this research was to examine on question: What is the resident's preference of awareness regarding urban agriculture at rooftop garden? The purpose of this study is to understand the resident's preference of awareness regarding urban agriculture at rooftop garden. The awareness and potential of rooftop urban agriculture are examined. In this research a method presented quantitative-survey questionnaire distributed among of residents in The Heritage condominium in Selangor and Sri Putramas 2 in Kuala Lumpur. The result is expected to lead towards cognition and awareness to elevate sustainable building and promoting the usage of urban agriculture at rooftop gardening residential building. In conclusion of this research contain the result of survey questionnaire that related to awareness of urban agriculture at rooftop garden who residents take part in the survey are agree with this section. Furthermore, this study help to residents for receive a perfect environmental in their live area.

Roof garden can be used as natural environment in an urban setting. Rooftop agriculture with green roof systems can become an attractive possibility. The aesthetic value of green roofs is considered important in cities where roof escapes are dominated by gray color and unattractive structures. The instant objective of this research was to examine on question: What is the resident’s preference of awareness regarding urban agriculture at rooftop garden? The purpose of this study is to understand the resident’s preference of awareness regarding urban agriculture at rooftop garden. The awareness and potential of rooftop urban agriculture are examined. In this research a method presented quantitative - survey questionnaire distributed among of residents in The Heritage condominium in Selangor and Sri Putramas 2 in Kuala Lumpur. The result is expected to lead towards cognition and awareness to elevate sustainable building and promoting the usage of urban agriculture at rooftop gardening residential building. In conclusion of this research contain the result of survey questionnaire that related to awareness of urban agriculture at rooftop garden who residents take part in the survey are agree with this section. Furthermore, this study help to residents for receive a perfect environmental in their live area.

Green roof system is one of sustainable approach for energy consumption reduction and improving the aesthetic value of the built environment. The system has been adopted by most of developed countries; and in Malaysia, research on green roof studies are quite evolving however the implementation of the system is slow due to some perceptions and obstacles. Green roof has potential on providing benefits such as reduction on the urban heat island effect, reduces temperatures, pollution and improves the attenuation of stormwater. This paper will highlights on a preliminary review of the implementation green roof system in Malaysia and explores the performances of Malaysian green roof in order to highlight the performance of green roof under tropical climatic conditions using local configurations.

Dünya nüfusunun artması ve buna bağlı olarak yapılan kentsel göçlerle artan betonlaşma, yeşil alanların azalmasını beraberinde getirmiştir. Bireylerin nefes alabilecekleri ve günlük hayatın stresinden kurtulabilecekleri yeşil alanların azalması, insan sağlığını ve psikolojisini olumsuz yönde etkileyerek kentlerdeki yaşam kalitesinin azalmasına neden olmuştur. Özellikle 20. ve 21. yüzyılda bu durumun farkına varan tasarımcılar ve kullanıcılar yoğun kentsel alanlardaki yapıların çatılarını yeşil bir alana dönüştürmeyi hedeflemiştir. Bu amaç doğrultusunda ortaya çıkan yeşil çatılar, ekolojik ve ekonomik katkı sağlamanın yanı sıra, insanlar için rekreasyon alanı sağlayarak sosyalleşme mekânı yaratabilmektedir. 
Yeşil alanlar, özellikle de çocukların psikolojisine de olumlu etkiler sağlayarak sağlıklı bir yaşam için önem taşımaktadır. Çocuklar yeşil alanları oyun oynama, buluşma vb. amaçlar için kullanmaktadır. Kentteki yeşil alanların azalması çocukların oynayabilecekleri, buluşup konuşabilecekleri, toprakla temas edebilecekleri alanların yok olmasına, çocukların kapalı mekanlarda daha çok vakit geçirerek bu alanlardan uzak kalmalarına neden olmuştur. Bu durum, çocukların en çok vakit geçirdikleri yerler olan anaokullarında yeşil alan kullanımının önemini arttırmıştır. Yapılan çalışmada; 3-7 yaş grubu çocukların eğitim aldıkları anaokullarındaki yeşil çatıların rekreatif amaçlı kullanımlarının çeşitli parametreler doğrultusunda incelenmesi ve karşılaştırılması amaçlanmaktadır. Bu doğrultuda, yurt içi ve yurt dışından, yeşil çatı kullanımına sahip 5 anaokulu tespit edilmiştir. Seçilen beş farklı okul, yeşil çatı türü, çatının özel-yarı özel-kamusal kullanımı, rekreatif amaçlı kullanımı ve ekolojik amaçlı kullanımı olarak parametre üzerinden değerlendirilmiştir. Yapılan değerlendirmeler sonucunda, anaokullarındaki yeşil çatıların oyun, yeme-içme ve dinlenme alanı, tarım faaliyetlerini gerçekleştirme gibi eylemler için kullanılması, yapılan bitkilendirmeler ile çocukların doğa ile bütünleşmesine olanak sağlaması ve yağmur suyu toplama gibi sistemler ile sürdürülebilirliğe katkı sağlaması bakımından oldukça etkili bir çözüm olduğu görülmüştür.
Yeşil ve açık alanların çocuklar için olumlu etkiler sağladığı göz önüne alındığında anaokullarında yeşil çatı kullanımı hem sürdürülebilir hem de yenilikçi çözümler olarak karşımıza çıkmaktadır. Ülkemizde de bu tür bitkilendirilmiş çatıların kullanımının yaygınlaşması sağlanmalı, anaokullarında ve diğer eğitim yapılarında tercih edilmesi için teşvik edilmeli ve bu konudaki akademik çalışmalar arttırılmalıdır.

The increase in the world population and the increase in the concretization caused by the urban migration caused the decrease of the green areas. The decrease in the green spaces where individuals can breathe and get rid of the stress of daily life has negatively affected human health and psychology, causing a decrease in the quality of life in cities. Especially in the 20th and 21st century, designers and users who have become aware of this issue have aimed to turn the roofs of buildings in dense urban areas into a green space. In addition to providing ecological and economic contribution, the green roofs created for this purpose can create a recreation space for people and create a space for socialization.
Green spaces are important for a healthy life, especially by providing positive effects on the psychology of children. Children use green spaces for playing and meeting. The decrease in the green spaces in the city has caused the destruction of the areas where children can play, meet and talk, and come into contact with the soil, causing children to spend more time indoors and stay away from these areas. This increased the importance of using green spaces in kindergartens, where children spend most of their time. In this study, it is aimed to investigate and compare the recreational use of green roofs in kindergartens of 3-7 age group in accordance with various parameters. In this respect, 5 kindergartens with green roof usage were identified from domestic and abroad. Five different schools were evaluated with four parameters: green roof type, private-semi-private-public use, recreational use and ecological use. As a result of the evaluations, it was seen that green roofs in kindergartens are used for actions such as play, eating-drinking and resting area, performing agricultural activities, planting made possible for children to integrate with nature and contributing to sustainability with systems such as rainwater collection.
Considering that green and open spaces have positive effects for children, the use of green roofs in kindergartens is both sustainable and innovative solutions. In our country, the use of such vegetated roofs should be expanded, encouraged to be preferred in kindergartens and other educational structures and academic studies on this subject should be increased.

The integration of vegetation, irrigation and natural materials like soil with the roof structure of a building may be a functional, ecologically sound, and cost-effective design strategy for reducing or dampening the effect of heat gain from solar radiation. This experiment explores the possibilities of reducing the energy consumption of buildings in the arid (hot and dry) climate of Phoenix, Arizona by analyzing the effect of solar radiation on different roof systems. Four roof systems were tested and compared against a reference case (standard roof). The test boxes were instrumented in order to measure temperature at a number of locations within the enclosed space as well as at layers of the roofing system. The purpose was to observe and analyze the effectiveness of the four test roof systems as compared to the standard roof. Analysis of the temperature data acquired from a 24 hour period in early summer 2005 provides clear indicators of the cooling effect of an irrigated planted roof system, while non-irrigated systems may turn out to be counter productive to the goal of reducing heat gain to the interior resulting from solar radiation on the roof.

According to projects and practices that the Italian botanists and ecologists are carrying out for bring- ing “more nature in the city”, new insights for a factual integration between ecological perspectives and more consolidated aesthetic and agronomic approaches to the sustainable planning and manage- ment of urban green areas are provided.

This article aims to assess the spatial distribution of the IST (internal surface temperatures) in the ceiling and DBT (dry bulb temperatures) of a LGR (light green roof) in a test cell. Cover systems known as green roofs have the potential to retain rainwater and help reduce runoff. However, the characteristic considered in this work is the insulation capacity of this kind of coverage. To evaluate the spatial distribution of temperatures in an environment with light green roof, we proposed a new method for acquisition of series of climatological data and temperatures according to spatial and temporal approaches of dynamic climatology. Climatological data were provided by an automatic weather station and temperatures were collected in a test cell with light green roof. The spatial distribution of surface temperatures and internal air temperature (DBT) are based on the concepts of a climatic episode and typical experimental day from the study of the dynamic climatology. The results l...

Zazeleňovanie horizontálnych a vertikálnych častí budov nie je v súčasnosti ničím novým. Takmer v celej Európe (okrem stredomorských oblastí) ale aj v niektorých afrických krajinách vychádzal vývoj obydlí zo stavieb zahĺbených do zeme. V staroveku nachádzame zmienky o strešných záhradách, z ktorých mnohé boli veľkolepými architektonickými dielami. Azda najznámejším objektom s uplatnením prvkov strešnej, ale aj vertikálnej zelene sú takzvané „visuté záhrady kráľovnej Semiramis“, ktoré dal kráľ Nabukadnesar II. postaviť pravdepodobne pre svoju ženu Amytis, a sú jedným zo Siedmych divov Sveta. Zelené strechy pôsobia v krajine prirodzene, nenarúšajú ju a vytvárajú symbiózu s okolitým prostredím. Zvlášť pri ruinách hradov, kostolov či iných opustených stavbách, kde si prirodzenou sukcesiou nachádza zeleň svoje miesto osídľovaním puklín, korún múrov či rôznych výklenkov, sa použitie zelených striech javí ako najvhodnejší spôsob zastrešovania zakonzervovaných častí stavieb. Ak nie je možné z nejakého dôvodu prekryť rekonštruovaný objekt jeho pôvodným typom strechy s tradičnou krytinou, obvykle sa objekt zastreší pultovou strechou. Pri takomto type sa ako najvhodnejšie javí použitie extenzívnej zelenej strechy. Podobne možno postupovať pri obnovách klenieb či domurovaniach veľmi širokých múrov.

Urban growth has been fast for decades. Because money is very important in this urban-based world, humanity focuses on economic development, and is often too busy to deal with sustainability. Therefore, in a world that is constantly changing, creating sustainable cities that contain a diverse range of habitats supporting plant establishment is essential. Some surprising urban habitats in which plants can grow, such as cracks on pavements and walls, rocky areas, abandoned places and roofs might be extremely important for sustainability, while urban spaces are under artificial pressure. In this study, which suggesting a method to create more sustainable green roofs for urban areas, and considering roof vegetation is already important for supporting the ecology of urban areas, we surveyed 37 roofs in an urban part of Trabzon city focusing on the habitat effect. We found 51 plant species growing on these 37 roofs, and determined five different roof vegetation typologies in the research area. The main goal in any artificial green roof is to cover roof surfaces with vegetation, and success is considered a perfect coverage rate. We found roof surface size, species richness, size of the sunlit part, daily sunlight duration, and depth of the substrate are the most effective habitat attributes on vegetation coverage on rooftops in the research area.

Constructing a model for predicting the thermal effect of green roofs and walls on the built environment
Quantifying the microclimatic effects of green roofs and walls
From theory to practice: challenges and opportunities
The case of the Municipality of Athens: policies and implementation

In a country like India, where temperatures may reach 40 degrees Celsius, everyone wants relief from the sweltering heat, but only a few can afford it. As a result, passive cooling is a low or no energy approach that relies on heat gain management and heat dispersion to offer thermal comfort. Heat Protection, Heat Modulation, and Heat Dissipation are the three basic types of passive cooling systems. The combined effect of approaches from each category on a prototype room is examined in this research, which includes shading and green roofs for heat protection, thermal mass (PCM) for heat modulation, and cross ventilation for heat dissipation. Thermal mass is a term that describes a substance's ability to store heat. The three primary phases of a Thermal Energy Storage (TES) system are thermal charging, thermal storage, and thermal discharging. Phase Change Materials or PCM are latent heat storage materials. The roof is one of the most exposed parts of a house to the sun, accounting for over half of the heat gain in a single-story home. As a result, heat protection might be a viable option for lowering heat gain via the roof. A green roof, or a roof with vegetation, is one such system that operates on the principle of evapotranspiration, which is the combined action of soil evaporation and plant transpiration. Another effective method of heat shielding that is used in everyday life is shading. Shading is a basic technique for blocking sunlight before it enters a structure by using structural components such as overhangs, light shelves, horizontal louvres, or blind systems. Cross ventilation is a natural cooling method that uses wind to force cold air into a structure through an opening while driving warm air out. Natural ventilation of this sort is low-cost and ensures that a structure is suitably cooled. There are many such different passive cooling techniques used in different regions of the world in the form of individual as well as hybrid system. This project focuses mainly on Hybrid Systems. Thus, the objective of this project is to integrate PCM and other secondary passive cooling techniques for creating a hybrid passive cooling system to provide thermal comfort.

Green 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...