scholarly journals A comparative study on rainfall runoff control indicators of green roof

2020 ◽  
Vol 20 (6) ◽  
pp. 2036-2042
Author(s):  
Ke Zhou
Keyword(s):  
Comparative Study ◽  
Green Roof ◽  
Reduction Rate ◽  
Green Roofs ◽  
Mean Value ◽  
Rainfall Runoff ◽  
Control Effect ◽  
Runoff Reduction ◽  
Runoff Control ◽  
Reduction Effect

Abstract The rainfall runoff reduction effect on green roofs was analyzed and tested by comparative rainfall runoff monitoring on impermeable roofs (sloping, plane). The evaluation index of rainfall runoff interception benefit (relative runoff reduction rate, rainfall control rate) on green roofs was studied. The results show that compared with sloping and level roofs, the change range of green roof runoff reduction rate relative to level and sloping roofs is 20.0–98.3% and 3.8–92.3%, and the mean value is 48.4% and 34.3% respectively. It is obvious that the green roof has better rainfall runoff reduction effect. It can be seen from the single rainfall control effect that the variation range of green roof rainfall runoff control rate is 36.0% to 99.0%, and the total rainfall control rate is 57.6%, which reflects that the green roof has the better rainfall control effect. Through comparative study, it can be concluded that the rainfall runoff control rate is more suitable for the design index of green roofs.

Simulating rainfall runoff and assessing low impact development (LID) facilities in sponge airport

2020 ◽  
Vol 82 (5) ◽  
pp. 918-926
Author(s):  
Jing Peng ◽  
Xiang Zhong ◽  
Lei Yu ◽  
Qianqian Wang
Keyword(s):  
Water Depth ◽  
Low Impact Development ◽  
Green Roof ◽  
Reduction Rate ◽  
Low Frequency ◽  
Normal Operation ◽  
Return Periods ◽  
Rainfall Runoff ◽  
Reduction Effect ◽  
Total Inflow

Abstract The appearance of extreme weather causes frequent airport flooding, which has a serious impact on the normal operation of an airport. In this study, three simulation scenarios are set in order to study the effect of low impact development (LID) facilities (green roof and vegetative swale) on the water depth of overflow junctions and total inflow to the study area outlet in an airport at different rainfall return periods (2 a, 5 a, 20 a and 50 a). Vegetative swale has better reduction effect on water depth of overflow junctions than has green roof. The reduction rate of vegetative swale is about 25–52% at different rainfall return periods, but the effect of green roof is not obvious. For the double peak rainstorm, the reduction effect on the water depth of overflow junctions after setting vegetative swale for the first rain peak is better than that for the second rain peak. Under the condition of 2 a, 5 a, and 20 a, the total inflow reduction rates of study area outlet after applied green roof and vegetative swale are 16.85%, 20% and 22.17% respectively, and the effect is poor (only 2.26%) at low-frequency return period (50 a). This study can provide theoretical guidance for the design of LID facilities of a sponge airport.

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.

scholarly journals Runoff Reduction Effect of Rainwater Retentive Green roof

KIEAE Journal ◽  
2016 ◽  
Vol 16 (1) ◽  
pp. 67-71 ◽  
Author(s):  
So-Young Baek ◽  
Hyun-Woo Kim ◽  
Mi-Kyeong Kim ◽  
Moo-Young Han
Keyword(s):  
Green Roof ◽  
Runoff Reduction ◽  
Reduction Effect

scholarly journals Monitoring and Modeling the Long-Term Rainfall-Runoff Response of the Jacob K. Javits Center Green Roof

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1494 ◽  
Author(s):  
Noura Abualfaraj ◽  
Joseph Cataldo ◽  
Yara Elborolosy ◽  
Daniel Fagan ◽  
Sloane Woerdeman ◽  
...  
Keyword(s):  
New York ◽  
Environmental Protection Agency ◽  
Green Roof ◽  
Substantial Reduction ◽  
Cost Effective ◽  
Green Roofs ◽  
The United States ◽  
Rainfall Runoff ◽  
Substrate Depth

Drainage from the 27,316-m2 Jacob K. Javits Convention Center (JJCC) green roof was investigated in the field to quantify the system’s long-term rainfall-runoff response. The JJCC hosts one of the largest extensive green roofs in the United States. Utilizing four years of rooftop monitoring data collected using a weather station, custom designed and built drainage systems, three Parshall flumes equipped with pressure transducers, and weighing lysimeters, this study quantified the 25.4-mm-deep green roof’s ability to decrease the volume and peak rate of runoff. With parameters derived from the site, the Environmental Protection Agency Stormwater Management Model (EPA-SWMM) predicted event total runoff volume and event peak runoff rates to within +10% to −20% and +25% to −15% of the observations, respectively. The analysis further indicated that approximately 55% of the cumulative precipitation that fell on the JJCC extensive green roof during the monitoring period (warm weather months, June 2014–November 2017) was captured and retained. The average percent retained on an event-basis was 77%, and average event runoff coefficient was 0.7, implying a substantial reduction in the volume and rate of runoff generated from the roof compared to the pre-green roof condition, when most, if not all, of the precipitated water would have immediately resulted in runoff. Our research suggests that, on average, 96% of rainfall events 6.35 mm or less were retained within the green roof, whereas 27% of the total event volume was retained for events greater than 12.7 mm in depth. A sensitivity analysis suggests if the substrate depth were increased, better stormwater capture performance would be achieved, but only up 127 mm, whereas increased precipitation coupled with warmer temperatures as a result of climate change could decrease the performance by up to 5%, regardless of substrate depth. An equivalency analysis suggested that even shallow green roofs can significantly reduce the required stormwater detention volume that New York City requires on new development. This particular green roof appears to be more than 18 times as cost-effective as a subsurface cistern would be for managing an equivalent volume of stormwater in Midtown Manhattan.

scholarly journals Assessing the significance of evapotranspiration in green roof modeling by SWMM

2018 ◽  
Vol 20 (3) ◽  
pp. 588-596 ◽  
Author(s):  
Aviva Gabriel Limos ◽  
Kristine Joy Bernardo Mallari ◽  
Jongrak Baek ◽  
Hwansuk Kim ◽  
Seungwan Hong ◽  
...  
Keyword(s):  
Urban Areas ◽  
Low Impact Development ◽  
Green Roof ◽  
Green Roofs ◽  
Management Model ◽  
Rainfall Runoff ◽  
Storm Water Management Model ◽  
Hydrologic Processes ◽  
Runoff Modeling ◽  
Modeling Software

Abstract Green roof is a low impact development (LID) practice used to mitigate imperviousness in urban areas and to reduce flood risks. In order to have sufficient designs and accurate runoff predictions, computer models should be utilized with full understanding of green roofs' hydrologic processes. Evapotranspiration is usually considered important by researchers in the water balance modeling of a green roof. The Storm Water Management Model (SWMM) version 5.1 is widely utilized rainfall-runoff modeling software which has LID controls capable of modeling green roofs. A previous study has evaluated the performance of this model in green roof simulations for single events without considering evapotranspiration in its application, but attained negative outcomes. Thus, the objective of this study is to determine the significance of considering evapotranspiration in producing accurate runoff simulations specifically using SWMM 5.1. The results of this study have shown that when evapotranspiration was not considered, simulations failed to agree with observed values, whereas when evapotranspiration was considered, simulated runoff volumes attained a very good fit with the observed runoff volumes proving the significance of evapotranspiration as an important parameter in green roof modeling.

scholarly journals Water Resilience by Centipedegrass Green Roof: A Case Study

Buildings ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 141 ◽  
Author(s):  
Shuai Hu ◽  
Lijiao Liu ◽  
Junjun Cao ◽  
Nan Chen ◽  
Zhaolong Wang
Keyword(s):  
Soil Moisture ◽  
Green Roof ◽  
Green Roofs ◽  
Saturated Soil ◽  
Water Retention Capacity ◽  
Water Runoff ◽  
Retention Capacity ◽  
Runoff Reduction ◽  
Eremochloa Ophiuroides ◽  
Rain Events

Centipedegrass (Eremochloa ophiuroides) is a low-maintenance turfgrass. The first extensive green roof of centipedegrass was established in TongZhou Civil Squares in 2014. However, storm-water-runoff reduction, water-retention capacity, and plant-water requirements by a centipedegrass green roof has not yet been defined. The soil moisture dynamics, rainwater-retention capacity, runoff reduction, and plant evapotranspiration were investigated by simulated centipedegrass green roof plots, which were constructed in the same manner as the green roofs in TongZhou Civil Squares in 2018. The results showed that the centipedegrass green roof retained 705.54 mm of rainwater, which consisted 47.4% of runoff reduction. The saturated soil moisture was 33.4 ± 0.6%; the excess rainfall over the saturated soil moisture resulted in runoff. The capacity of rainwater retention was negatively related to the soil moisture before rain events and was driven by plant evapotranspiration. Drought symptoms only occurred three times over the course of a year when the soil moisture dropped down to 10.97%. Our results indicate that the rainwater retained in the soil almost met the needs of plant consumption; a further increase of rainwater retention capacity might achieve an irrigation-free design in a centipedegrass green roof.

scholarly journals Experimental study on the selection of common adsorption substrates for extensive green roofs (EGRs)

2021 ◽  
Vol 83 (4) ◽  
pp. 961-974
Author(s):  
Chen Xu ◽  
Zaohong Liu ◽  
Guanjun Cai ◽  
Jian Zhan
Keyword(s):  
Synergistic Effects ◽  
Low Cost ◽  
Reduction Rate ◽  
Green Roofs ◽  
High Porosity ◽  
Retention Capacity ◽  
Factors Affecting ◽  
Runoff Reduction ◽  
Practical Engineering ◽  
Selection Of

Abstract Adsorption substrate in the substrate layer of an extensive green roof (EGR) is one of the most important factors affecting rainwater retention and pollution interception capacity. However, the contact time between runoff and adsorption substrate is extremely short in actual rainfall, and adsorption substrate cannot show fully rainwater retention and pollution interception capacity. So, selection of adsorption substrate based on its physical properties and theoretical adsorption capacity is unreliable. In this study, eight commonly-used adsorption substrate experimental devices are constructed with the same configuration. The delayed outflow time and runoff reduction rate of each device, along with event measurement concentration (EMC), average EMC, and cumulative pollutant quantity of SS, ammonium (NH4+), nitrate (NO3−), total nitrogen (TN), and total phosphorus (TP) in each device outflow under nine simulated rainfall events are measured and evaluated. The results indicate that vermiculite has a significant interception effect on NH4+ and TP with the advantages of low bulk density, high porosity, low cost, and a good rainfall runoff retention capacity under torrential rain and downpour events. In future practical engineering and related studies of EGR, attention should be paid to ameliorating the deficiencies of the adsorption substrates and optimizing their synergistic effects when combined with nutrient substrates.

scholarly journals In-situ monitoring of energetic and hydrological performance of a semi-intensive green roof and a white roof during a heatwave event in the UK

2019 ◽  
Vol 30 (1) ◽  
pp. 56-69 ◽  
Author(s):  
Yangang Xing ◽  
Phil Jones
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Performance Monitoring ◽  
Green Roof ◽  
Weather Conditions ◽  
Green Roofs ◽  
In Situ Monitoring ◽  
Runoff Reduction ◽  
Peak Runoff ◽  
The Uk

Due to the increasing magnitude and high frequency of urban heatwaves, recently, there has been a surge of interest in the reflective roofs and the vegetative green roofs. Along with the rising temperature, there are also more frequent droughts and rainfall which have led to wider changes in weather conditions subsequently affecting the performance of green roofs and white roofs. However, there is still a lack of research in comparing dynamic energetic and hydrological performance of green roof and white roofs during heatwave events. This paper introduces a newly constructed outdoor test rig (installed with a semi-intensive green roof and an aluminium white roof) and a few initial monitoring results. The hydrological performance monitoring results showed that, although a noticeable peak runoff reduction of the white roof was observed, more significant water retention of green roofs had been established. The energetic performance monitoring results indicated that the green roof performed better than the white roof during the heatwave event reducing solar heat gains by 76% during day time, improving U-value by 28% and reducing indoor air temperature by 2.5°C. The peak indoor air temperature reduction in the green roof space occurred during late afternoons (around 7 pm).

scholarly journals Theoretical Framework to Assess Green Roof Performance in Mitigating Urban Flooding as a Potential Nature-Based Solution

2021 ◽  
Vol 13 (23) ◽  
pp. 13231
Author(s):  
Arunima Sarkar Basu ◽  
Francesco Pilla ◽  
Srikanta Sannigrahi ◽  
Rémi Gengembre ◽  
Antoine Guilland ◽  
...  
Keyword(s):  
Simulation Study ◽  
Literature Search ◽  
Green Roof ◽  
Green Roofs ◽  
Flood Management ◽  
Literature Survey ◽  
Urban Flooding ◽  
Soil Permeability ◽  
Runoff Reduction ◽  
Different Types

Increases in extreme hydro-meteorological events due to climate change and decreases in soil permeability and infiltration due to urbanization have increased the risk of flooding, particularly in cities. The limitation of the expansion of conventional drainage systems to manage excess stormwater leads to the application of nature-based solutions (NBS) to control flooding. This study explores potential of green roof NBS for rainfall-fed flood reduction, which can utilize existing roof space for deployment. A detailed literature survey using systematic literature-search procedures was conducted to investigate the performance of extensive/intensive green roofs in runoff reduction using monitoring/modeling approaches. Since limited studies have explored the use of semi-intensive green roofs for flood management, a new simulation study has been developed to compare the effectiveness of semi-intensive green roofs. The performance of different types of vegetation used on green roofs in runoff reduction was investigated using a simulation study, which was validated using a real-world green roof deployed in Dublin.

scholarly journals Simulating the Hydrological Impact of Green Roof Use and an Increase in Green Areas in an Urban Catchment with i-Tree: A Case Study with the Town of Fontibón in Bogotá, Colombia

Resources ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 68 ◽  
Author(s):  
David Bautista ◽  
Carlos Peña-Guzmán
Keyword(s):  
Green Roof ◽  
Green Roofs ◽  
Complete Removal ◽  
Total Flow ◽  
Vegetation Removal ◽  
Green Cover ◽  
Green Areas ◽  
Runoff Control ◽  
Social Environmental ◽  
The Town

Urbanization has produced various social, environmental, and hydrological impacts, such as reduced biodiversity, increased urban temperatures, ecosystem degradation, air and water pollution, changes to hydrological processes, groundwater recharge alterations, increased prevalence of floods, vegetation removal, and potential increases in unstable soils. Finding solutions to mitigate the impacts of urbanization is of vital importance in the development and planning of cities, and particularly so for developing countries. One strategy gaining momentum is the use of green roofs and larger green areas (greater green cover under trees, with the purpose of increasing the permeable area) for runoff control. In this study, a simulation was carried out using the i-Tree Hydro software that involved the urban basin in the Fontibón area of Bogotá, Colombia, with the aim of observing the hydrological benefits of trees, green areas, and permeable zones. Five scenarios were proposed in which green roof coverage was implemented (20% and 50% increases in green areas in Scenarios 1 and 2), coverage under existing trees was enhanced (50% and 100% increase in Scenarios 4 and 5), and finally a complete removal of green zones in Fontibón was simulated (Scenario 3). The town is relatively susceptible to a reduction in its existing green areas, with an increase in total flow of more than 50% for one scenario considered. Thus, an increase in the permeable coverage under trees (50% and 100% increased coverage under existing trees) provided the best strategy for mitigating the impacts of urbanization by reducing the total, maximum, and average impervious flow by 3%, 4%, and 8%, respectively. Finally, an increase in permeable zones corresponding to plants was proposed via the implementation of green roofs. However, this strategy showed a response to the reduction in the lowest total flow at 1%.

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