Assessing the Retention Capacity of an Experimental Green Roof Prototype

Silva, Mariana da; Najjar, Mohammad K.; Hammad, Ahmed W. A.; Haddad, Assed; Vazquez, Elaine Garrido

doi:10.3390/w12010090

Cited by 25 publications

(23 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This finding is in line with other studies [33,41]. Nevertheless, the range of the retention rate reported in the literature is highly variable and the comparison between different case studies is difficult, since several factors can influence the performance [42], such as the precipitation regime.…”

Section: The Drainage Flow Ratesupporting

confidence: 91%

Factors Controlling the Hydraulic Efficiency of Green Roofs in the Metropolitan Area of Milan (Italy)

et al. 2021

View full text Add to dashboard Cite

Green roofs (GRs) are considered sustainable solutions for the adaptation of urban water management to climate change. The use of GRs is particularly promising in urban environments like the Metropolitan Area of Milan, the most urbanized area in Italy. In this work, we evaluated the subsurface runoff coefficient at the event-time scale, for more than one year of observations, of 68 small-scale test beds comprising different configurations of green roofs (e.g., different vegetations, types and depths of growing media, and different slopes) installed in the Metropolitan Area of Milan. The objectives of this study are three-fold. Firstly, the controlling factors of the hydraulic have been assessed for efficiency. We calculated a mean drainage flow rate of 51%, finding that growing media play a significant role in determining the drainage flow during the spring, at the beginning of the vegetative period. During this season, water retention in fertilized beds increases significantly. At the beginning of the summer, the vegetation cover is able to significantly reduce the drainage flow, playing an even more crucial role with respect to the growing medium material. However, we found that the vegetation type (grass field and Sedum) does not play a significant role in the retention processes. Secondly, the delay of the peak flow rate was determined. We found a precipitation peak delay from 1 to 2 h, which would be sufficient to guarantee environmental benefits for urban drainage. Finally, the factors controlling the hydraulic efficiency of GRs for individual precipitation events were assessed. We found that soil moisture and cumulated precipitation are both significant factors determining the drainage flow rate. In conclusion, we point out that soil moisture is one of the main parameters characterizing GR drainage and should be further considered in future research efforts devoted to the analysis of GR performance.

show abstract

Section: The Drainage Flow Ratesupporting

confidence: 91%

Factors Controlling the Hydraulic Efficiency of Green Roofs in the Metropolitan Area of Milan (Italy)

et al. 2021

View full text Add to dashboard Cite

show abstract

“…These are considerable challenges in terms of maintaining and restoring green spaces within urban areas. Urbanization also affects the hydrological cycle, by reducing infiltration on the one hand and simultaneously increasing runoff on the other [4]. Green roofs (GRs) (also known as living roofs, vegetable roofs, or eco-roofs [5]) are building roofs which are entirely or partially covered with vegetation and growth medium (so called substrate) planted over a waterproofing membrane [6].…”

Section: Introductionmentioning

confidence: 99%

Green Water from Green Roofs—The Ecological and Economic Effects

Bus

Szelągowska

2021

Sustainability

View full text Add to dashboard Cite

Green roofs (GRs) have been one of the most popular solutions for water harvesting in urban areas. Apart from their water retention role and increasing biodiversity, they constitute the missing link between the built and the natural environment, which is required for sustainable human living in cities. This paper aims to calculate the ecological (EE) and economic effect (EcE) of water harvesting via GRs, by contrasting with a traditional roof, and to perform an economic analysis of the social cost benefits that GRs generate during their life cycle, using the Net Present Value (NPV) method. All the calculations and analyses were conducted for both intensive and extensive GRs in 11 of the largest municipalities in Poland, with a population of >250,000 inhabitants. According to the results of this study, water retention and the economic and ecological effects of GRs are highest in the municipalities with the highest assumed number of GRs (Warsaw, Krakow, Wroclaw, and Szczecin). The average EE and EcE equals 507,000 m3/yr and 621,000 USD/yr. The NPV results show that the effectiveness of investments in intensive GRs is, to a certain extent, more significant than in extensive GRs and the average equals 60.77 and 4.47 USD/yr for intensive and extensive GRs, respectively. The results could serve as a reference for the evaluation and optimization of the energy efficiency of rainwater harvesting schemes, in European cities.

show abstract

“…The module is tapped for the control of water output, which goes through a gutter and is carried to the rain box (Garrido Neto 2012). In August 2018, the green roof was rebuilt and the bromeliads were rearranged, as shown in Figure 2 (Silva, 2020). Bromeliads are typical of the tropical and subtropical areas of the Americas; this plant is used here since it is adaptable, requires little maintenance, and resists intense solar radiation, which are necessary elements for the local climate of Rio de Janeiro (Garrido Neto 2016).…”

Section: Methodsmentioning

confidence: 99%

Assessing rainwater quality treated via a green roof system

Sá

Najjar

Hammad

et al. 2021

Clean Techn Environ Policy

Self Cite

View full text Add to dashboard Cite

The shortage of water worldwide is increasingly worrying. Studies in the field suggest that sustainable water resource management via water recycling is fundamental to alleviate the issue. The use of rainwater is an important alternative source that must be considered, mainly, in the water crisis facing the planet. When integrated with the concept of green roofs, the capturing and treatment of rainwater in these structures becomes an even more ecological and sustainable practice. The water drained by the roof can be used for non-potable uses, such as flushing toilet bowls. One of the main concerns when using rainwater, even for non-potable uses, is the quality of the water available, so as not to put users' health at risk. In this way, the present work proposes to experimentally analyze the quality of rainwater drained in a green roof prototype for reuse purposes. The green roof prototype was installed on an experimental bench. After each rain event (four in total), two water samples were collected in the following situations: rainwater captured directly by a container next to the bench, and rainwater drained by the green roof prototype, captured by a container through existing drains at the base of the prototype. The analyzes of the collected samples were carried out at the Environmental Engineering Laboratory (LEMA / UFRJ) and performed according to the Standard Methods for the Examination of Water and Wastewater. Specifically, the experiments examine physicochemical and biological parameters following a rain event on a green roof prototype for sanitary use. Experimental results that were observed and analyzed include color, turbidity, pH, ammonia nitrogen, nitrite, nitrate, orthophosphate, total coliforms, and thermotolerant coliforms to indicate the rainwater quality from green roofs. The majority of parameters assessed were within the value thresholds indicated by the Brazilian standards, while the results of orthophosphate, fecal coliforms, color, and turbidity were not. The greatest divergence is in the concentration of orthophosphate, where a concentration of 10.88mg/L was obtained in this experimental study while other authors present values of 0.1 and 0.01mg/L. Total coliforms also presented high values, but within the expected range. Comparisons with technical documents and international references related to water quality to identify possibilities of the use of rainwater were also conducted. Results indicate that the water quality has the same order of quantity for turbidity, nitrite, and ammonia nitrogen parameters across the standards. Based on such observations, filtration and disinfection processes are therefore required in the green roof system for the use of rainwater for sanitary. Finally, the experimental study of rainwater quality on the green roof presented similar results comparing with international references. The use of green roofs combined with the use of rainwater demonstrates the potential and benefits as an alternative to face the water crisis.

show abstract

Assessing the Retention Capacity of an Experimental Green Roof Prototype

Cited by 25 publications

References 62 publications

Factors Controlling the Hydraulic Efficiency of Green Roofs in the Metropolitan Area of Milan (Italy)

Factors Controlling the Hydraulic Efficiency of Green Roofs in the Metropolitan Area of Milan (Italy)

Green Water from Green Roofs—The Ecological and Economic Effects

Assessing rainwater quality treated via a green roof system

Contact Info

Product

Resources

About