Publikum Nynäshamn docks directly to the west façade of the existing 9 story municipal building with seven floors of open activity space. These surround a full-height atrium across which a two-floor living plant green wall provides the monumental living presence of nature and its ecosystem services in an office environment.  Plants also grace the other side of this two story wall, providing a living backdrop for the heart of the building - the raised three floor high assembly hall. A lunchroom with balconies above the assembly hall provides city views and a roof garden for municipal staff. The two floor high lobby beneath the assembly hall provides a new internal city street between Banana Square and Floravägen – a former back alleyway.  A ground-level colonnade walkway with benches surrounds the new and old buildings, inviting citizens into the building spaces. Public space and circulation is further enhanced with a new passageway opening up the former dead-end southwest corner of Banana Square where the old municipal building met Folkets hus (People’s House). A generous stair complex in this new sunny southern square provides spontaneous seating and meeting spaces as well as additional outdoor access to the two floor café, art gallery, and the largest green roof – one of three accessible green roofs that enhance social and ecological values.  Pedestrian movement can continue through this new passageway directly down to Svandammen (swan pond), and in the opposite direction, directly up to Banana square from the commuter rail station.   The café and two-floor meeting room spaces provide evening and weekend public social spaces for the city residents, complementing existing bars and restaurants in the adjoining Folkets Hus.   Reduced use of energy is encouraged with progressively rising central spaces allowing for the possibility of natural stack ventilation, thermal mass energy storage in concrete (HD/F) slabs, and generous natural daylight through the glazed curtain wall climate shell surrounding the building.  Abstracted winged structures crown the top of the building and grace the building entrances, inspired by the sightings of sea eagles reported in this coastal area, and provides both a signum for the building (instead of a more traditional municipal building tower) and extended surface for rainwater collection that can be used for watering indoor green plant walls and the roof garden vegetation.  The deeper soil of the intensive green roofs not only provides more uptake and retention of rainwater (and thus reduced peak flow rates favorable for stormwater management) but also allows planting of larger, woody plants and bushes, and even small trees, which in turn, among other social and ecological benefits, add natural habitat to a predominantly impervious-surfaced downtown urban area.

Population growth has lead to an increase in development and impervious areas in urban settings. Post-development conditions cause several problems for stormwater management such as limited space for stormwater storage systems and the conveyance of pollution picked up by runoff to near by water bodies. Green Roofs with cisterns have been shown to attenuate the peak flow of storm events and reduce the pollution load leaving a site and entering nearby water bodies. The purpose of this research is to expand the available research data on green roofs with cisterns by investigating the water quality and hydrology effects of different green roof designs including depth of media, an additional pollution control layer beneath the growth media, and different drainage layer materials. Furthermore, a comparison study is performed on the cistern water quality, direct filtrate water quality, and control roof filtrate water quality. Results show that phosphorus concentrations are lower when using a pollution control layer beneath the growing media, and that evapotransporation and filtrate factor values from the 4-inch media and the 8-inch media are approximately equal for one year. However, hydrograph results show that the 8-inch media design has a lower peak flow and longer attenuation when compared to the 4-inch media design for a single storm event. Furthermore, the drainage layer material has no significant effect on the water quality or hydrology of the green roof discharge. The data also emphasizes the importance and effectiveness of the incorporation of a cistern into a green roof system.

No description available.

Yes / There is general agreement on the importance of green roofs as ways of reducing GHG emissions, reducing overall costs and improving sustainability in urban areas. This systematic literature review highlights life cycle sustainability assessment as an essential criterion to evaluate green roofs. A bibliometric analysis was used to quantitatively review relevant literature. The Scopus database was chosen as a bibliographic database of academic publications. Thes period of search started from 2003 and final search was conducted on February 15, 2023. Based on further in-depth reading, 88 publication records which met the selection criteria, including 74 papers and 14 conference papers. Researchers from the United States contributed almost 31 % of the documents. We evaluated leading studies in this field and discussed assessment method, system boundaries and research gaps through a critical literature review and a systematic search review. Finally, we propose a framework and identify a gap and future research. The environmental aspect of green roofs have received more attention than economic issues. We found that most economic evaluations of green roofs are limited to their construction stage. As yet there is no comprehensive social study on green roofs. We considered a unified study of the economic, environmental impact and social evaluation of green roofs to be warranted. Additionally, various measurement methods should be used to assess the economic profitability of green roofs over the long term. In summary, this study provides a deeper understanding of the environmental, social, and economic performance of green roofs and identifies research gaps as well as future research directions. / The full-text of this article will be released for public view at the end of the publisher embargo on 21 Nov 2024.

Yes / There is general agreement on the importance of green roofs as ways of reducing GHG emissions, reducing overall costs and improving sustainability in urban areas. This systematic literature review highlights life cycle sustainability assessment as an essential criterion to evaluate green roofs. A bibliometric analysis was used to quantitatively review relevant literature. The Scopus database was chosen as a bibliographic database of academic publications. Thes period of search started from 2003 and final search was conducted on February 15, 2023. Based on further in-depth reading, 88 publication records which met the selection criteria, including 74 papers and 14 conference papers. Researchers from the United States contributed almost 31 % of the documents. We evaluated leading studies in this field and discussed assessment method, system boundaries and research gaps through a critical literature review and a systematic search review. Finally, we propose a framework and identify a gap and future research. The environmental aspect of green roofs have received more attention than economic issues. We found that most economic evaluations of green roofs are limited to their construction stage. As yet there is no comprehensive social study on green roofs. We considered a unified study of the economic, environmental impact and social evaluation of green roofs to be warranted. Additionally, various measurement methods should be used to assess the economic profitability of green roofs over the long term. In summary, this study provides a deeper understanding of the environmental, social, and economic performance of green roofs and identifies research gaps as well as future research directions. / The full-text of this article will be released for public view at the end of the publisher embargo on 25 Nov 2024.

With over half the world's population now living in cities, urban areas represent one of earth's few ecosystems that are increasing in extent, and are sites of altered biogeochemical cycles, habitat fragmentation, and changes in biodiversity. However, urban green spaces, including green roofs, can also provide important pools of biodiversity and contribute to regional gamma diversity, while novel species assemblages can enhance some ecosystem services. Green roofs may also mitigate species loss in urban areas and have been shown to support a surprising diversity of invertebrates, including rare and endangered species. In the first part of this study I reviewed the literature on urban invertebrate communities and diversity to better understand the role of green roofs in providing habitat in the context of the larger urban mosaic. My review concluded that, while other factors such as surrounding land use and connectivity are also important to specific invertebrate taxa, local habitat variables contribute substantially to the structure and diversity of urban invertebrate communities. The importance of local habitat variables in urban green spaces and strong support for the habitat complexity hypothesis in a number of other ecosystems has led to proposals that "biodiverse" roofs--those intentionally designed with varied substrate depth, greater plant diversity, or added elements such as logs or stones--would support greater invertebrate diversity, but there is currently limited peer reviewed data to support this. In order to address the habitat complexity hypothesis in the context of green roofs, in the second part of this study I surveyed three roofs designed primarily for stormwater management, three biodiverse roofs, and five ground-level green spaces, from March until September of 2014 in the Portland metropolitan area. Beetles (Coleoptera) were sampled bi-weekly as representatives of total species diversity. Biodiverse roofs had greater richness, abundance, and diversity of beetle species compared to stormwater roofs, but were not more diverse than ground sites. Both biodiverse roofs and ground sites had approximately 20% native beetle species while stormwater roofs had only 5%. Functional diversity was also higher on biodiverse roofs with an average of seven trophic groups represented, while stormwater roofs averaged only three. Ground sites, biodiverse roofs, and stormwater roofs each grouped distinctively in terms of beetle community composition and biodiverse roof communities were found to be positively correlated with roof age, percent plant cover, average plant height, and plant species richness. These results support the findings of previous studies on the importance of local variables in structuring urban invertebrate communities and suggest that biodiverse design can reliably increase greenroof diversity, with the caution that they remain no replacement for ground level conservation.

A presente pesquisa teve como objetivo principal analisar experimentalmente o comportamento térmico de um sistema de cobertura verde leve (CVL) e, também, comparar o comportamento térmico entre os diferentes sistemas de cobertura, frente aos ganhos térmicos no período de transição entre as estações primavera-verão, na cidade de São Carlos-SP. Os sistemas de cobertura em análise foram: 1) aço galvanizado, 2) telha de fibrocimento, 3) laje pré-moldada cerâmica, 4) telha cerâmica e 5) cobertura verde leve (CVL). A CVL caracteriza-se por um sistema construtivo que possui laje pré-moldada cerâmica impermeabilizada com resina poliuretana vegetal, geomanta tridimensional leve e flexível para drenagem, camada reduzida de substrato e grama em sua superfície. As vantagens em relação à utilização das coberturas verdes, em geral, estão relacionadas à regulação de temperaturas, a melhora na eficiência energética das edificações, a capacidade de retenção das águas pluviais, ao aumento das áreas verdes, a atenuação dos efeitos das ilhas de calor, além da contribuição estética e social no ambiente urbano. A metodologia adotada baseou-se na definição do dia típico experimental e nos parâmetros da inércia térmica aplicados aos componentes construtivos da cobertura. As medições experimentais foram realizadas em células de teste no canteiro experimental da Universidade de São Paulo (USP), pelo grupo de ecotecnologias: novos materiais e procedimentos. Foram armazenados em um sistema de aquisição automática de dados, registros referentes às temperaturas do ar externo e interno às células de teste e da temperatura superficial interna dos sistemas de cobertura. Como resultado, a CVL apresentou um bom comportamento no que se refere à atenuação das variações de temperaturas internas à edificação, frente às temperaturas do ar externo. Obteve, também, a menor temperatura superficial na face interna do sistema de cobertura, quando comparada aos outros sistemas construtivos. Por tanto, conclui-se que a CVL constitui-se de alternativa viável para construção, devido a sua capacidade de amortecimento e atraso do fluxo térmico (inércia térmica), contribuindo com o estabelecimento de temperaturas internas mais amenas e, além disso, por fundamentar-se em preceitos de uma arquitetura de maior consonância com o ambiente natural. / The present research main objective was to experimentally analyze the thermal behavior of an extensive green roof system and also to compare different roof system thermal behavior, considering their thermal profits in the period of transition between the stations spring-summer, in the city of São Carlos-SP. The roof systems analyzed were: 1) galvanized steel, 2) earth flax, 3) paving-stone, 4) ceramic tile and 5) extensive green roof. The extensive green roof can be characterized as a constructive system that holds a waterproofed paving-stone with vegetable resin, a slight and flexible three-dimensional geomat, used for draining, a reduced layer of substratum and grass in its surface. The green roofs advantages are mainly related to temperatures regulation, improvement of energy efficiency in constructions, possibility of pluvial waters retention (runoff), increase of green areas, attenuation of heat islands effects, beyond the aesthetic and social contribution for the urban environment. The methodology used was based on the definition of the experimental typical day and the parameters of the thermal inertia applied to the constructive components of the cover. The experimental measurements had been carried in test of cells located in the experimental base of the University of São Paulo (USP), by the group of ecotecnologys: new materials and procedures. They were stored in a system of automatic acquisition of facts, records regarding the temperatures of the internal and external air in the test of cells, and the superficial temperature of the internal roof systems. As a result, the extensive green roof presented a good behavior, considering the attenuation of the construction internal temperatures variations, facing the temperatures of the external air. It presented, also, the lesser superficial temperature of the internal face of the roof system, when compared with the other constructive systems. Therefore, one concludes that the extensive green roof consists of a feasible alternative for construction, due to its capacity of damping and delaying the thermal flow (thermal inertia), contributing to the establishment of pleasant internal temperatures and, moreover, for basing its rules on architecture patterns more sensitive to environmental issues.

El presente proyecto propuso un método experimental de medición de temperaturas internas con el fin de estudiar, comparar y entender la respuesta térmica frente al frío y al calor de cuatro células de ensayo denominadas Control (Sin vegetación) y tres células de ensayo con diferentes combinaciones de vegetación (cubiertas y fachadas) instaladas en una región de clima tropical. En ellas fueron medidas las temperaturas superficiales internas (TSI) y temperaturas del Bulbo Seco (TBS) mediante equipos específicos, un data logger, conectado a dos multiplicadores. Los datos fueron recogidos por un año y dentro de ese periodo fueron seleccionados los días críticos a estudiar. Varios datos climatológicos fueron considerados para abordar la influencia de las oscilaciones del tiempo meteorológico (episodios climáticos) en el ambiente interno construido, para lo cual fueron aplicados fundamentos de la Climatología Dinámica frente al comportamiento térmico de las células de ensayo. Los datos de las principales variables climáticas (radiación solar, humedad relativa y precipitación) fueron registradas en la Estación Meteorológica del CRHEA. Los resultados revelan que la célula de ensayo con vegetación en cubierta y fachadas, presenta más resistencia a las variaciones de temperaturas diarias, es decir, mejor comportamiento térmico, ya que muestra las menores amplitudes térmicas, los mayores retrasos térmicos, las menores temperaturas en días de calor extremo y las mayores en días de frío. Durante el día crítico de calor, las mayores diferencias entre las temperaturas máximas internas del aire, se presentan entre la célula construida con materiales convenciones y la célula que posee fachadas verdes y cubierta vegetal, de 2ºC y en torno a 3ºC en el caso de las temperaturas superficiales. Para el día crítico de frío, la diferencia entre ellas es de 1ºC para los valores de temperatura del aire, y de 2.2ºC para valores de temperaturas superficiales. Así, uso de vegetación en los edificios puede ser considerado una técnica capaz de mantener las condiciones internas más placenteras no solo en épocas calurosas, reduciendo la incidencia de la radiación solar directa, sino también en invierno, debido a su propiedad de aislante térmico que impide las rápidas pérdidas de calor, como ocurre en la célula sin vegetación. Los resultados obtenidos ponen de manifiesto que las hipótesis planteadas fueron alcanzadas, comprobando así, que el uso de vegetación combinado en fachadas y cubiertas contribuye a la mejora del comportamiento térmico, favoreciendo las condiciones térmicas internas en periodos de mayor o menor temperatura externa. / The present research proposed an experimental method for measuring internal temperatures of buildings, in order to study, compare, and understand the thermal response of four test cells against cold and heat, determined: control (without vegetation) and three test cells with different combinations of vegetation (on roofs and/or facades); installed in a tropical climate region. Internal surface temperatures (IST) and dry bulb temperatures (DBT) were measured using appropriate equipment, consisting of a data logger connected to two multipliers. Data were collected for one year and, during that period, the critical days that would be assessed were selected. Climatic data were considered in order to evaluate the influence of weather oscillations (climatic events) on the internal built environment, for which the principles of Dynamic Climatology were applied to understand the thermal behaviour of the test cells. The data obtained from the primary climatic variables (solar radiation, relative humidity, and precipitation) were recorded at the CRHEA. The results showed that the test cell with a green roof and green facades displayed higher resistance to changes in daily temperature, i.e., better thermal behavior, since it faced lower temperature intervals, higher thermal delays, lower temperatures on days of extreme heat, and higher temperatures on cold days. With respect to the critical heat day, the main differences between maximum internal air temperatures occurred between the cell constructed with conventional material and the cell that was built with green facades and a green roof, of 2°C in relation to the internal air temperature, and approximately 3°C with respect to surface temperatures. Regarding the critical cold day, the difference between test cells was of 1°C for air temperature values, and 2.2°C for surface temperature values. Therefore, the use of vegetation in construction can be considered a technique capable of maintaining the most pleasant indoor conditions, not only in hot climates, reducing the incidence of direct solar radiation, but also in the winter, due to thermal insulation properties that prevent the rapid loss of heat, which occurs in cells lacking vegetation. The obtained results show that the initial hypotheses were proven, thus confirming that the application of vegetation on facades and roofs contributes to the improvement of thermal performance, favoring internal thermal conditions during periods of higher or lower external temperatures.

A presente pesquisa teve como objetivo principal analisar experimentalmente o comportamento térmico de um sistema de cobertura verde leve (CVL) e, também, comparar o comportamento térmico entre os diferentes sistemas de cobertura, frente aos ganhos térmicos no período de transição entre as estações primavera-verão, na cidade de São Carlos-SP. Os sistemas de cobertura em análise foram: 1) aço galvanizado, 2) telha de fibrocimento, 3) laje pré-moldada cerâmica, 4) telha cerâmica e 5) cobertura verde leve (CVL). A CVL caracteriza-se por um sistema construtivo que possui laje pré-moldada cerâmica impermeabilizada com resina poliuretana vegetal, geomanta tridimensional leve e flexível para drenagem, camada reduzida de substrato e grama em sua superfície. As vantagens em relação à utilização das coberturas verdes, em geral, estão relacionadas à regulação de temperaturas, a melhora na eficiência energética das edificações, a capacidade de retenção das águas pluviais, ao aumento das áreas verdes, a atenuação dos efeitos das ilhas de calor, além da contribuição estética e social no ambiente urbano. A metodologia adotada baseou-se na definição do dia típico experimental e nos parâmetros da inércia térmica aplicados aos componentes construtivos da cobertura. As medições experimentais foram realizadas em células de teste no canteiro experimental da Universidade de São Paulo (USP), pelo grupo de ecotecnologias: novos materiais e procedimentos. Foram armazenados em um sistema de aquisição automática de dados, registros referentes às temperaturas do ar externo e interno às células de teste e da temperatura superficial interna dos sistemas de cobertura. Como resultado, a CVL apresentou um bom comportamento no que se refere à atenuação das variações de temperaturas internas à edificação, frente às temperaturas do ar externo. Obteve, também, a menor temperatura superficial na face interna do sistema de cobertura, quando comparada aos outros sistemas construtivos. Por tanto, conclui-se que a CVL constitui-se de alternativa viável para construção, devido a sua capacidade de amortecimento e atraso do fluxo térmico (inércia térmica), contribuindo com o estabelecimento de temperaturas internas mais amenas e, além disso, por fundamentar-se em preceitos de uma arquitetura de maior consonância com o ambiente natural. / The present research main objective was to experimentally analyze the thermal behavior of an extensive green roof system and also to compare different roof system thermal behavior, considering their thermal profits in the period of transition between the stations spring-summer, in the city of São Carlos-SP. The roof systems analyzed were: 1) galvanized steel, 2) earth flax, 3) paving-stone, 4) ceramic tile and 5) extensive green roof. The extensive green roof can be characterized as a constructive system that holds a waterproofed paving-stone with vegetable resin, a slight and flexible three-dimensional geomat, used for draining, a reduced layer of substratum and grass in its surface. The green roofs advantages are mainly related to temperatures regulation, improvement of energy efficiency in constructions, possibility of pluvial waters retention (runoff), increase of green areas, attenuation of heat islands effects, beyond the aesthetic and social contribution for the urban environment. The methodology used was based on the definition of the experimental typical day and the parameters of the thermal inertia applied to the constructive components of the cover. The experimental measurements had been carried in test of cells located in the experimental base of the University of São Paulo (USP), by the group of ecotecnologys: new materials and procedures. They were stored in a system of automatic acquisition of facts, records regarding the temperatures of the internal and external air in the test of cells, and the superficial temperature of the internal roof systems. As a result, the extensive green roof presented a good behavior, considering the attenuation of the construction internal temperatures variations, facing the temperatures of the external air. It presented, also, the lesser superficial temperature of the internal face of the roof system, when compared with the other constructive systems. Therefore, one concludes that the extensive green roof consists of a feasible alternative for construction, due to its capacity of damping and delaying the thermal flow (thermal inertia), contributing to the establishment of pleasant internal temperatures and, moreover, for basing its rules on architecture patterns more sensitive to environmental issues.

Expansion och förtätning av städer leder till att såväl areal som andel hårdgjord yta ökar i våra stadsmiljöer. Detta genererar en ökad dagvattenavrinning eftersom regnvattnet inte har samma möjlighet att infiltrera i naturmarker och grönområden. Den ökade mängden dagvatten riskerar att orsaka problem i områden där ledningsnätet dimensionerats för de dagvattenmängder som tidigare varit aktuella. Att utöka ledningsnätets kapacitet är ofta mycket kostsamt och det är därför önskvärt att istället minska belastningen på de befintliga systemen. En allt vanligare metod för detta är att byggnaders takyta bekläds med växter, så kallade gröna tak. De gröna taken har potential att minska den avrunna volymen, fördröja avrinningen och dämpa de maximala flödena. Det råder dock osäkerheter kring hur dessa förmågor påverkas av bland annat olika väderförhållanden och takets vattenmättnadsgrad samt vid olika typer av nederbördshändelser.   Syftet med detta examensarbete var att undersöka möjligheten att simulera avrinningen från gröna tak med hjälp av en befintlig funktion i modelleringsprogrammet SWMM från US Environmental Protection Agency samt med hjälp av Mike Urban från företaget DHI. Ett mål var att sedan använda en av modellerna för att utvärdera hur gröna tak kan påverka belastningen på ett befintligt ledningsnät. Mätdata avseende bland annat nederbörd, avrinning och potentiell avdunstning erhölls från Veg Tech AB och AgroTech A/S. Mätningarna hade utförts vid företagens demonstrationsanläggning i Taastrup, Danmark, och omfattade avrinning från gröna tak med tre olika tjocklekar: 4 cm moss-sedum, 7 cm sedum-ört-gräs och 11 cm sedum-ört-gräs, samt ett hårdgjort referenstak. Inledande dataanalyser av de gröna takens kapacitet visade att takens magasineringskapacitet ökade med en ökad taktjocklek, där de tjockare taken kunde fullständigt magasinera större nederbördshändelser än vad som var fallet för det tunnaste taket. En analys av sambandet mellan nederbördsmängd och avrunnen volym visade ett starkare samband för regn med 60 och 120 minuters varaktighet än vad som var fallet för kortare varaktigheter.   Jämförelser av resultaten hos de båda modelleringsprogrammen visade på olika styrkor och svagheter och ingen av programvarorna gav en i alla avseenden tillfredställande simulering av avrinningen. Mike Urban gav generellt en högre förklaringsgrad men gav alltid en överskattning av den avrunna volymen över en längre tidsperiod. SWMM gav en bättre överensstämmelse med uppmätt avrinning än Mike Urban under de första månaderna av simuleringsperioden, men gav generellt en förskjutning av avrinningsförloppet. För kalibreringen mot 4 cm taktjocklek gav SWMM också en mer korrekt avrunnen långtidsvolym, medan den för de andra konstruktionerna gav liknande resultat som var fallet för Mike Urban. I ett exempel användes en av modellerna för att simulera avrinningen från MAX IV-laboratoriet i Lund. Resultaten visade att det då laboratoriet täckts med gröna tak endast behövdes ett en fjärdedel så stort fördröjningsmagasin för att översvämningar skulle undvikas på ett nedströms beläget fiktivt ledningsnät än vad som var fallet för hårdgjorda tak. / Larger and denser cities result in increasing amounts of impervious surfaces in urban areas. This generates an increase in storm water runoff, as the rainwater is prevented from infiltrating in natural soils and instead flows along the paved surfaces. The increased amount of storm water runoff is liable to cause problems in areas where the storm water system has been designed to handle the amounts of runoff previously generated in the area. Upsizing the capacity of the pipelines is usually costly, and it is therefore desirable to instead reduce the load on the existing system. One way of achieving this is to cover the rooftops with vegetation, so called green roofs. Green roofs are growing in popularity and have the potential to reduce the rate and volume of runoff, as well as attenuating the peak discharge. There are however uncertainties regarding how their abilities are affected by for example the antecedent weather conditions and the moisture content of the roof, as well as by various storm events.   The purpose of this Master’s Thesis was to study the possibility to simulate the runoff from green roofs using an existing function in the modelling software SWMM by US Environmental Protection Agency, and using Mike Urban by the company DHI. An additional objective was to use on of the designed models to evaluate how green roofs can affect the load on an existing storm water system. Measurements of precipitation, runoff and potential evapotranspiration were obtained from Veg Tech AB and AgroTech A/S. The measurements had been carried out at their demonstration site in Taastrup, Denmark, and included runoff from green roofs of three different thicknesses: 4 cm moss-sedum, 7 cm sedum-herb-grass and 11 cm sedum-herb-grass, as well as an impervious roof used as reference. Initial analyses of the data showed that the storage capacity increased with an increased roof thickness. The thicker roofs were able to completely retain the rainfall from larger storm events than what was the case for the thinnest roof. An analysis of the relationship between precipitation depth and runoff volume showed a stronger correlation for rains with 60 and 120 minutes duration than what was the case for shorter durations.   Comparisons of the two models’ performance showed different strengths and weaknesses, and none of the models were able to simulate runoff in a way that was satisfactory in all aspects. Mike Urban generally gave a higher coefficient of determination but consistently overestimated the discharged volume for extended time periods. SWMM gave a better conformity in observed runoff than Mike Urban during the first months of the simulation period, but generally gave a time lag in the runoff hydrograph. For the 4 cm roof calibration, SWMM also gave a more correct long-time runoff volume, while both models performed similarly for the other roof thicknesses. In an example, one of the models was used to simulate the runoff from the MAX IV laboratory in Lund. The results showed that in order to avoid flooding in the fictitious downstream storm water network, there had to be a four times larger detention pond in the case where conventional roofs where used compared to the scenario using green roofs.