Influence of environmental factors on retention of extensive green roofs with different substrate composition

Baryła, Anna; Karczmarczyk, Agnieszka; Bus, Agnieszka; Hewelke, Edyta

doi:10.1051/e3sconf/20198600026

Cited by 6 publications

(11 citation statements)

References 36 publications

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“…Baryła et al found that ADP as well as antecedent volumetric moisture content are the parameters that determine the preceding level of moisture in the substrate. They found that the relationship between these two parameters was moderately negative, whereas ADP did not exhibit statistically significant correlation with retention [Baryła et al, 2019]. It should be emphasized that during the investigations described in the current paper, the lengths of periods elapsed from the previous total saturation PSTS obtained in the case of 6 rainfalls were relatively similar.…”

Section: Resultsmentioning

confidence: 48%

Influence of the Hydrogel Amendment on the Water Retention Capacity of Extensive Green Roof Models

et al. 2020

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The goal of the research was to investigate the retention capacity of six green roof models (SHP1, SHP2, SHP3, SH, S, and SP) constructed with the use of the square-shaped plastic trays, Floradrain FD 25 drainage elements, SF filter sheets, and the specified extensive substrates (with or without the hydrogel amendment). The SHP1 and SHP2 models were constructed in March 2017, SHP3 and SHin November 2017, while S and SPin April 2018. Four models (SHP1, SHP2, SHP3, and SP) contained the plants (the goldmoss stonecrop Sedum Acre), whereas two models (S and SH) did not contain the vegetation. The substrates of SHP1, SHP2, SHP3, and SH models contained the hydrogel admixtures. The investigations were conducted with the use of simulated (and partially natural) precipitations. The water retention capacity of each green roof model was established based on the difference between the precipitation volume and the volume of runoff from a model. The results show that green roofs can be useful stormwater management tools. The calculated stormwater retention rates ranged from 29.50% to 85.15%. In most cases, the best water retention capacity was exhibited by the SHP3 model, constructed in November 2017 and planted in April 2018, containing the substrate amended with superabsorbent (cross-linked potassium polyacrylate). The similarly constructed SHP1 and SHP2 models, which were built in March 2017, in some cases had lower water retention capacity. These models contained older hydrogel and were overgrown with older, smaller, and worse looking plants, partially supplanted by mosses. Such results indicate that the efficiency of hydrogel may decrease over time. In many cases, the S (not vegetated, without hydrogel), SH (not vegetated, with substrate containing hydrogel), and SP (vegetated, without hydrogel) models had slightly lower water retention capacity. The results of investigations indicate that there was a relatively strong positive linear correlation between the retention depth and duration of the antecedent period elapsed from the preceding total (or substantial) saturation of the green roof models (labelled in this article as period since total saturation-PSTS). The weather conditions i.e. air temperature and relative humidity as well as PSTS are very important parameters that influence the retention capacity of the green roof models. The result show that duration of PSTS can be stronger correlated with the retention depth than antecedent dry period (ADP) elapsed from the end of last precipitation, regardless of its depth and intensity.

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Section: Resultsmentioning

confidence: 48%

Influence of the Hydrogel Amendment on the Water Retention Capacity of Extensive Green Roof Models

et al. 2020

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“…Schultz et al [39] reported that both the ADWP and the precipitation depth influence the amount of water retained within green roof during individual rain event. Baryla et al [40] found that both ADWP and the antecedent volumetric moisture content are the parameters that influence the preceding moisture level in the substrate and thus the retention depth. On the other hand, however, they reported not statistically significant correlation between ADWP and retention, but their research was conducted in natural conditions and they have taken into account all precipitations having diversified depths and intensities [40].…”

Section: Resultsmentioning

confidence: 99%

“…Baryla et al [40] found that both ADWP and the antecedent volumetric moisture content are the parameters that influence the preceding moisture level in the substrate and thus the retention depth. On the other hand, however, they reported not statistically significant correlation between ADWP and retention, but their research was conducted in natural conditions and they have taken into account all precipitations having diversified depths and intensities [40]. In another publication Baryla [41] found that the volume of precipitation, the initial moisture substrate, and ADWP have a significant effect on green roof retention.…”

Section: Resultsmentioning

confidence: 99%

Impact of the Hydrogel Amendment and the Dry Period Duration on the Green Roof Retention Capacity

Deska

Mrowieć

Ociepa

et al. 2020

Ecological Chemistry and Engineering S

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Climate changes as well as the urbanisation and economic development influence the characteristics of the stormwater runoff in the cities. The sealing of drainage basin surface leads to an increase of the runoff intensity, thereby decreasing the rainwater infiltration. This situation can lead to the risk of flooding in urban areas. Therefore, especially in great cities there is a need for application of such solutions that will support the operation of the sewage systems. The examples of such solutions are, among others, the green roofs. The paper presents the results of investigation of the water retention capacity of 4 green roof models containing following growing media: (1) the typical green roof substrate without any amendments, (2) the substrate with addition of about 1 % by weight of hydrogel (the cross-linked potassium polyacrylate), (3) the substrate containing about 0.25 % by weight of hydrogel, (4) the substrate with addition of expanded clay and perlite. The models were not vegetated in order to investigate only the water retention capacity of drainage elements and substrates. The water retention capacity of green roof models was investigated in the laboratory conditions with use of artificial precipitations simulated after diverse antecedent dry weather periods (ADWP) amounting to: 1, 2, 5, 7, and 12 days. The intensities of artificial precipitations were relatively high and ranged from 1.14 to 1.27 mm/min, whereas their durations ranged from 7.75 to 12.56 min. These values of intensities and durations corresponded to the design rainfall intensities calculated using Blaszczyk’s equation for annual rain depth equal to 600 mm and the return periods ranged from 5 to 15 years. The obtained results indicate that the water retention capacity of green roof models, expressed as the volumes (or depths) of rainwater retained within their structures, increases with an increase of ADWP. Results indicate that the relation between ADWP and the amount of water retained in the layers of green roofs in the case of relatively short antecedent dry weather periods provided for the analysis (from 1 to 7 days) may be approximately linear. The results of the one-way ANOVA indicate that in the case of all models there is a statistically significant difference between the values of retention depth for specified ADWP (p < 0.001). During more than half of simulated precipitations, especially in the case of longer ADWPs lasting 5, 7, and 12 days the best water retention capacity had Model 3, with substrate containing about 0.25 % by weight of hydrogel. On the other hand, the results show that the weakest retention capacity had Model 2 (with substrate containing 1 % by weight of hydrogel). In the case of longer ADWPs (lasting 7 and 12 days) relatively weak water retention capacity had Model 4 (with substrate containing the addition of expanded clay and perlite). It can be concluded that too large amount of hydrogel added to the substrate can have an unfavourable impact on the water retention capacity of green roofs.

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“…If the vegetated roof reaches its saturation level at a given time and under specific internal conditions, other factor's contribution may be significant (Stovin et al, 2015). Nevertheless, the effect of rainfall depth on retention would compensate for the other factors when the disparity between the two is substantial (Baryła et al, 2019).…”

Section: Rainfall Depth and Intensitymentioning

confidence: 99%

Rooftop Rainwater Control - Combining Storage Tank, Vegetation and Rooftop Retention

Adity

2023

Preprint

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<p>Over the past few years, rapid urbanization, population growth and the projected climate change have contributed to global water scarcity and urban flooding. Thus, the rainwater harvesting system in buildings is getting popular for increasing water efficiency and reducing stormwater runoff. However, it is required to size the rainwater harvesting system adequately for improving its operation. An oversized system increases the capital cost, while an undersized system results in an unreliable water source. Therefore, the storage tank's sizing is the most critical objective for optimizing the overall system in a dense urban location. Rainwater harvesting system and the vegetated roof technology can be particularly promising to address the issue because the vegetated roof and blue roof perform very well as a stormwater management tool by providing reduced stormwater runoff generation. The research identified the factors involved in managing runoff from a complex set of rooftop arrangements, having partially vegetated and non-vegetated areas and developed a set of guidelines to optimize the rainwater harvesting system by utilizing vegetated roofs. The research analyzed four mid-rise buildings of the Ryerson University campus, and the results confirmed that an increase in the total percentage of vegetated area coverage reduces the rainwater storage tank size to a great extent. For a small institutional building, a 40% agricultural roof performs the best for meeting the outside non-potable water demand reducing the annual overflow from the tank. For 60% vegetated area coverage, the municipal service water must supplement the rainwater to meet the total water demand. In terms of substrate depth, 150mm yields the most reasonable benefit. Finally, a blue roof should be combined with a vegetated roof to maximize the stormwater retention and detention onsite. </p>

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Influence of environmental factors on retention of extensive green roofs with different substrate composition

Cited by 6 publications

References 36 publications

Influence of the Hydrogel Amendment on the Water Retention Capacity of Extensive Green Roof Models

Influence of the Hydrogel Amendment on the Water Retention Capacity of Extensive Green Roof Models

Impact of the Hydrogel Amendment and the Dry Period Duration on the Green Roof Retention Capacity

Rooftop Rainwater Control - Combining Storage Tank, Vegetation and Rooftop Retention

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