scholarly journals Hydrological Performance and Runoff Water Quality of Experimental Green Roofs

Water ◽  
2018 ◽  
Vol 10 (9) ◽  
pp. 1185 ◽  
Author(s):  
Grzegorz Pęczkowski ◽  
Tomasz Kowalczyk ◽  
Katarzyna Szawernoga ◽  
Wojciech Orzepowski ◽  
Romuald Żmuda ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Green Roofs ◽  
Control Surface ◽  
Substrate Thickness ◽  
Storm Events ◽  
Runoff Water ◽  
Relative Retention ◽  
Runoff Reduction ◽  
Relative Retention Index

Within the scope of the conducted experiment the authors analysed the efficiency of runoff reduction by the system of extensive type green roofs. The observations were based on storm events in the area of Lower Silesia at the Agro and Hydrometeorology Station Wrocław-Swojec. The authors analysed the thickness of plant substrate, and also estimated the quality of runoff waters under the conditions of periodic atmospheric deposition. Also considered were such indicators as electrolytic conductivity, N, NO3−, NO2−, NH4+, P, PO43−. The experiment included roof substrates designed in two variants, with known hydraulic and physical properties of the soil material. The analysis was performed for models with vegetation layer based on pumice and zelolite, covered with five plant species from the sedum family. The modelling of the hydraulic properties was conducted with variably saturated medium, using the Hydrus 1D software. The performance of systems with primary layer thickness of 11 cm and 9, 8, 7, 6 and 5 cm was estimated. The designed models reduced the average peak flows to 89%, and in addition they caused a delay in the initiation of the runoff which was dependent on the intensity and distribution of rainfalls in time, and on the initial moisture of the profiles. Simulations, performed for variable substrate thickness, permit the conclusion that in the case of thin-layer profiles (5 cm), the relative retention index was decidedly lower and amounted to 35.9% for the substrate with zeolite (originally 60.6%) and 41% for the substrate with pumice (originally 65.7%). In the case of total nitrogen and phosphates, statistical analysis revealed significant differences (p < 0.05) in relation to specific concentrations in the rainwater and in the control surface. The total nitrogen in the runoff from the green roof was nearly twice as high as that in the rainwater and amounted to, on average, 8.3 mg L−1.

scholarly journals Analysis of roof greening technology impact on rain and meltwater retention

2020 ◽  
Vol 175 ◽  
pp. 11023
Author(s):  
Elena Sysoeva ◽  
Margarita Gelmanova
Keyword(s):  
High Efficiency ◽  
Green Roof ◽  
Experimental Studies ◽  
Green Roofs ◽  
Climatic Conditions ◽  
Water Runoff ◽  
Substrate Thickness ◽  
Runoff Reduction ◽  
The Usa ◽  
Analytical Review

Over the past 20 years, a large number of studies have been published on reducing storm runoff by various types of green roofs. This article analyzes the results of experimental studies presented in 39 publications on green roof runoff reduction in a climate similar to the climate of Russia: in Canada, the USA, Finland, Norway, France. An analytical review found that the ability of green roofs to retain rainfall varies from 20 to 99.5% depending on climatic conditions (duration and intensity of rains, duration of dry periods, solar radiation, temperature and humidity, wind conditions), the properties of green roof layers (moisture capacity of the substrate and a drainage layer, the substrate thickness), the type of vegetation, the geometry of a green roof (slope and orientation). Green roofs can be a useful tool for reducing urban storm water runoff. However, in order to ensure high efficiency, it is necessary to use green roof technology with other measures to reduce runoff.

An evaluation of rainwater runoff quality from selected white roof membranes

2012 ◽  
Vol 47 (1) ◽  
pp. 66-79 ◽  
Author(s):  
Anthony Cupido ◽  
Brian Baetz ◽  
Yiping Guo ◽  
Anna Robertson
Keyword(s):  
Field Research ◽  
Green Building ◽  
Green Roofs ◽  
Institutional Setting ◽  
Modified Bitumen ◽  
Runoff Water ◽  
Rainwater Runoff ◽  
Thermoplastic Polyolefin ◽  
Runoff Quality

While there has been research on rainwater quality and quantity from green roofs and some conventional roof systems, there does not appear to be any significant study regarding the quality of rainwater harvested from selected white membrane roof systems and subsequently treated for potable use in an urban, institutional setting. A new Leadership in Energy and Environmental Design (LEED®) Canada Gold facility on the campus of McMaster University in Hamilton, Canada offered an excellent opportunity to analyze the quality of rainwater from different roof assemblies. Field research was undertaken on the evaluation of three white roof membranes: modified bitumen finish ply, polyvinyl chloride (PVC), and thermoplastic polyolefin (TPO); and their effects on the runoff water quality were studied. An analysis of the quality of runoff was performed from each of these three membranes and compared with Ontario provincial drinking water standards. This paper provides the results of runoff quality testing on these membranes and their suitability for future institutional green building applications.

EFFECT OF GREEN ROOF AGE ON RUNOFF WATER QUALITY IN PORTLAND, OREGON

2018 ◽  
Vol 13 (2) ◽  
pp. 42-54 ◽  
Author(s):  
Jarrett Okita ◽  
Cara Poor ◽  
Jessica M. Kleiss ◽  
Ted Eckmann
Keyword(s):  
Water Quality ◽  
Urban Areas ◽  
Water Retention ◽  
Green Roof ◽  
Green Roofs ◽  
Dry Season ◽  
Rain Event ◽  
Wet Season ◽  
Runoff Water

Green roofs have become a common method to increase water retention on-site in urban areas. However, the long-term water quality of runoff from green roofs is poorly understood. This study evaluated the water quality of stormwater runoff from a regular (non-vegetated) roof, a green roof installed 6 months previously, and a green roof installed 6 years ago in Portland, Oregon. Samples of runoff were taken during every rain event for 10 months, and analyzed for total phosphorus (TP), phosphate (PO3-4), total nitrogen (TN), nitrate (NO-3), ammonia (NH3), copper (Cu), and zinc (Zn). Runoff from the green roofs had higher concentrations of TP and PO3-4 and lower concentrations of Zn compared to the regular roof. Average TP concentrations from the 6-year old roof and 6-month old roof were 6.3 and 14.6 times higher, respectively, than concentrations from the regular roof, and average PO3-4 concentrations from the 6-year old roof and 6-month old roof were 13.5 and 26.6 times higher, respectively, compared to the regular roof. Runoff from the 6-month old green roof had higher concentrations of TP and PO3-4 than the 6-year old green roof during the wet season, but lower concentrations during the dry season. The 6-month old green roof installations where receiving waters are sensitive or impaired may need additional treatment methods to reduce phosphorus levels. As green roofs age, water retention decreases and phosphorus leaching increases during the dry season.

scholarly journals Runoff and Water Quality in the Aspect of Environmental Impact Assessment of Experimental Area of Green Roofs in Lower Silesia

2020 ◽  
Vol 12 (11) ◽  
pp. 4793 ◽  
Author(s):  
Grzegorz Pęczkowski ◽  
Katarzyna Szawernoga ◽  
Tomasz Kowalczyk ◽  
Wojciech Orzepowski ◽  
Ryszard Pokładek
Keyword(s):  
Performance Indicator ◽  
Green Roofs ◽  
The Elderly ◽  
Control Surface ◽  
Retention Performance ◽  
Green Architecture ◽  
Quality Of Water ◽  
Urban Conditions ◽  
Lower Silesia

Green architecture, including green roofs, can limit the effects of urbanization. Green roofs soften the thermal effect in urban conditions, especially considering the significant increase in the European and global population and that a significant share of the age group, mainly the elderly is exposed to diseases caused by high temperatures. We studied runoff and the quality of water from green roof systems in Lower Silesia, within the area of the Agro and Hydrometeorology Station Wrocław-Swojec, in the years 2012–2016. In the study, two systems with a vegetation layer based on light expanded clay aggregate and perlite were analyzed. The studies were based on the assessment of peak flow reduction, rainwater volume preservation and peak wave reduction. The calculated maximum retention performance indicator, relative to rainfall, for perlite surfaces was up to 65%, and in relation to the control surface up to 49%. In addition, the quality of water from runoff was estimated in the conditions of annual atmospheric deposition, taking into account such indicators as electrolytic conductivity; the content of N, NO3, NO2, NH4, P, PO4; and the content of metals, Cu, Zn, Pb and Cd. The load of total nitrogen exceeded the values of concentration in rainwater and amounted to 7.17 and 13.01 mg∙L−1 for leca and perlite, respectively. In the case of the metal content, significantly higher concentrations of copper and zinc from green surfaces were observed in relation to precipitation. For surfaces with perlite, these were 320 mg∙L−1 and 241 mg∙L−1, respectively, with rainwater concentrations of 50 and 31 mg∙L−1.

Effectiveness of green roofs in reduction of rainfall-fed runoff: A case study in Dublin, Ireland

2021 ◽  
Author(s):  
Bidroha Basu ◽  
Arunima Sarkar Basu ◽  
Srikanta Sannigrahi ◽  
Francesco Pilla
Keyword(s):  
Flood Control ◽  
Water Retention ◽  
Green Roof ◽  
Green Roofs ◽  
City Centre ◽  
Urban Drainage ◽  
Storm Events ◽  
Land Area ◽  
Runoff Reduction

&lt;p&gt;Increase in extreme rainfall and storm events due to climate change and decrease in water retention in soil due to urbanization has increased the risk of flooding in cities globally. Since majority of the cites are mostly developed, expanding the conventional urban drainage system to account for the excess runoff produced by the rainfall event has limited scope. The challenge is to develop sustainable urban drainage systems (SUDS) to reduce runoff and create a flood control system in major cities. One of the SUDS that are becoming popular is the use of nature-based solutions (NBSs). A set of conventional NBSs to mitigate flood risk include bioswales, bio-retention, tree pits, infiltration trenches. However, even though their performance in flood control is found to be effective, they require considerable land area for deployment, which might be difficult to obtain in cities. For this purpose, green roofs have becoming popular as an alternative NBS in flood control, as it does not require any additional land area for deployment. This study investigates the effectiveness of a green roof in reduction of runoff via real-world case study. A green roof deployed in the CHQ building located at the city centre in Dublin, Ireland has been considered for the study. The green roof has a total size of 70 sq. m. Performance of the green roof in runoff reduction was measured based on rainfall and water retention data collected at four modular units, each having 1 sq. meter area, located at the centre of the roof with an IoT weight scale. The data has been collected for 1 week at 3-minute interval, and the reduction in runoff with and without the presence of the green roof has been estimated. The performance of the green roofs in runoff reduction was found to vary between 20-40% depending on the intensity of storm events.&lt;/p&gt;

First flush effects in an urban catchment area in Aalborg

1998 ◽  
Vol 37 (1) ◽  
pp. 251-257 ◽  
Author(s):  
Torben Larsen ◽  
Kirsten Broch ◽  
Margit Riis Andersen
Keyword(s):  
Water Quality ◽  
Catchment Area ◽  
Quality Parameters ◽  
Average Concentration ◽  
First Flush ◽  
Storm Events ◽  
Urban Catchment ◽  
Discharge Measurements ◽  
Quality Measurements

The paper describes the results of measurements from a 2 year period on a 95 hectare urban catchment in Aalborg, Denmark. The results of the rain/discharge measurements include 160 storm events corresponding to an accumulated rain depth of totally 753 mm. The water quality measurements include 15 events with time series of concentration of SS, COD, BOD, total nitrogen and total phosphorus. The quality parameters showed significant first flush effects. The paper discusses whether either the event average concentration or the accumulated event mass is the most appropriate way to characterize the quality of the outflow.

The quality of runoff water collected from a wheat field margin in Greece

2002 ◽  
Vol 89 (1-2) ◽  
pp. 117-125 ◽  
Author(s):  
S.E. Tsiouris ◽  
A.P. Mamolos ◽  
K.L. Kalburtji ◽  
D. Alifrangis
Keyword(s):  
Runoff Water ◽  
Field Margin ◽  
Wheat Field

Fractal tools to analyse the spatial variability of Blue Green Solutions in an urban area

2021 ◽  
Author(s):  
Gustavo Otranto-da-Silva
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Model Performance ◽  
Green Roofs ◽  
Initial State ◽  
Runoff Reduction ◽  
Build Environment ◽  
Input Variables ◽  
Neighborhood Scale ◽  
Design Options

&lt;div&gt; &lt;p&gt;&lt;span&gt;A city's response to a rainfall event depends not only on the rainfall spatial-temporal variability, but also on the spatial distribution and the initial state of its Blue Green Solutions (BGS), such as green roofs. They hold back runoff and may prove being critically important elements of blue-green build environment.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;The aim of this study was first to adapt the existing hydrological model to the urban area of Melun (France), to validate it and then to assess numerically an optimal configuration of green roofs&amp;#160;to mitigate pluvial floods for particularly vulnerable areas. &lt;/span&gt;&lt;span&gt;The main focus was put on the investigation of interactions between rainfall space-time scales and resulting hydrological response over fine scales, all being controlled by the performance assessment of BGS. &lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;This presentation will particularly illustrate how fractal &lt;/span&gt;&lt;span&gt;tools were used to:&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;- highlight the scale dependency of the input variables and its e&lt;/span&gt;&lt;span&gt;ff&lt;/span&gt;&lt;span&gt;ects on gridded model performance;&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;- explore, &lt;/span&gt;&lt;span&gt;analyse&lt;/span&gt;&lt;span&gt; and represent the influence of BGS location and configuration on the mitigation of runoff associated with short-duration, high-intensity rainfall at neighborhood scale;&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;&amp;#160;- identify the urban design options that maximize the potential for runoff reduction&lt;/span&gt;&lt;span&gt;. &lt;/span&gt;&lt;/p&gt; &lt;/div&gt;&lt;div&gt; &lt;p&gt;&lt;span&gt;In overall, these &lt;/span&gt;&lt;span&gt;results may serve as a referential &lt;/span&gt;&lt;span&gt;for upscaling the optimized implementation of BGS in urban areas, by considering other urban infrastructures and their interactions.&lt;/span&gt;&lt;/p&gt; &lt;/div&gt;

scholarly journals Simulation of Low Impact Development (LID) Practices and Comparison with Conventional Drainage Solutions

Proceedings ◽  
2018 ◽  
Vol 2 (11) ◽  
pp. 640 ◽  
Author(s):  
Ioannis M. Kourtis ◽  
Vassilios A. Tsihrintzis ◽  
Evangelos Baltas
Keyword(s):  
Water Management ◽  
Design Process ◽  
Low Impact Development ◽  
Green Roofs ◽  
Storm Water ◽  
Management Model ◽  
Storm Events ◽  
Storm Water Management Model ◽  
Runoff Volume ◽  
Peak Runoff

The present work aims at quantifying the benefit of Low Impact Development (LID) practices in reducing peak runoff and runoff volume, and at comparing LID practices to conventional stormwater solutions. The hydrologic-hydraulic model used was the Storm Water Management Model (SWMM5.1). The LID practices modeled were: (i) Green roofs; and (ii) Permeable pavements. Each LID was tested independently and compared to two different conventional practices, i.e., sewer enlargement and detention pond design. Results showed that for small storm events LID practices are comparable to conventional measures, in reducing flooding. Overall, smaller storms should be included in the design process.

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